Document
SECURITY INFORMATION i .
—.— ANALYTICAL EVALUATION OF EFFECT OF EQUIVALENCE RATIO INLET-AIR TEMPERATURE, AND COMBUSTION PRESSURE ON PERFORMANCE OF SEVERAL POSSIBLE l RAM-JET FUELS By Leonard K. Tower end Benson E. Gammon Lewis Flight Propulsion Labor atory Cleveland, Ohio
NATIONAL ADVISORY COMMITTEE
FOR AERONAUTICS
WASHINGTON September 14, 1953 , TBCH LIBRARY NAFB, Nkl —-—.
lx
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W RM E53G14 .
NATIONAL AIJvI&oRY coMMITTm FOR AERONAIJTICS &+&/WH Ml?J@2RMIXlM.
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ANALYTICAL EVAIUN?ION OF EIIF’13CT OF EQUIVAIZN2E RATIO, --AIB ~, AND C(2MHJSTIXlN PNHSURE ON PEN?ORMANCE aF0EvER4L POSSIBLE RAM-JET FUELS By Leonard K. Tower and Benson E. (lanmon An analytical Investigation conducted to determine the theoretical air specific impulse perfomnance of several fuels over a range of equi- valence ratios, inlet-air temperatures, and combustion pressures is reported herein. The fuels include octene-1, 50-percent-magnesimn slurry, boron, pentaboranej diborane, hydrogen, carbon, and aluminum.
Inlet-air temperatures between 100° and 900° F are considered at a com- bustion pressure of 2 atmospheres j a conibustion pressure of 0.2 atmos- phere is also considered at an inlet-air temperature of 1.OOOF.
l The benefit to b specific impulse of an increase in inlet-air temperature at the higher equivalence ratios was reduced by such high temperature effects as dissociation and increased specific heats of .
the cmibustion products. An increase in cmibustion pressure from 0.2 to 2 atmospheres raised the air specific impulse level as much as 5 seconds at higher equivalence ratios.
The fuel consumption of penta- borane and tiborane remained below that of octene-1 despite the adverse effect of boron oxide vaporization on the performance of fuels contain- ing boron at combustion temperatures exceeding 3000° Rj the fuel con- sumption of boron became higher than that of octene-1 above this tem- perature. Boron, as well as diborane and pentaborane, provided higher air specific impulse than octene-1 at an equivalence ratto of 1.0.
Means are shown for extending the data to inlet conditions beyond the limited range of inlet-air temperatures and ccmbustion pressures considered. Also discussed are the determination of air specific im- pulse efficiency and cmbustion efficiency for qerimsntal data by the use of theoretical results and the estimation of the relative amounts of the various fuels required to maintain a fixed level of thrust in an engine.
NACA 1#1E53G14 .
INIROIXJCTION- The ever increasing performance required of high-speed ~rcraft ._ places new &minds--upon the propulsion system. Improved range, thrust, combustion efficiency, and couibustion stability characteristics may possibly be obtained by the use of the higbenergy $et-engine fuels.
These materials promise advantages over conventional hydrocarbon fuels because of their higher heating value on a gravimetric or volumetric basis, or because of the ease and stability of their combustion. Cur- rently designated among the htgh-ener~ Jet-engine fuels are certain of the light elements such as boron, aluminum, and magnesium, alloys and hydrides of these elements, and paintlike suspensions of the soltd ma- terials in a liquld hydrocarbon (slurries). -.
Considerable e~erimental work, summarized in reference 1, has been conducted with certain high- energy fuels to determine their suitability for selected applications .— in aircraft.
The NACA Lewis laboratory has determined some of the - physical properties and co?ibustion properties,of diborane, boron, mag- nesium, and aluminum, the metals having been burned in the form of powder, wire, and slurries (refs. 1 to 5).
The theoretical performance of M.@-energy rem-jet fuels 1s of interest both in evalualxkg experimental req~ts and in Judging the potentialities of proposed but untested materials. Theoretical com- parisons of fuels burned in a great excess of cool air maybe based upon heating valueq_ per pound of fuel, per pbund of air, or per cubic foot of fuel. When the temperatures obtained in the conibustlon process become very high, however, considerable energy is absorbedby dissocia- “ tion, vaporization, fusion, and increases in specific heats of the com- bustion products. The performance of fuels at elevated temperatures is thus determined both by the heating value of_the fuel andby the thermal properties of its conibustion products. Thus.the theoretical performance — of a fuel nmst be determined by an analytical method which can account -- for as many thermal effects as possible. ‘ By means of such an analytical method, the theoretical performance of many high-energy jet-engine fuels has been studied at a single com- bustor Inlet-air temperature of 100° F and at a combustion pressure of 2 atnmspheres (ref. 6). These data canbe compsred with ~erimental — data at the ssme conditions to evaluate the combustion test performance — of an engtie.
In practice, of course, few cases will be encountered where an engine is operating precl.selyat an inlet temperature of 100° F — and a combustion pressure of 2 atmospheres. :.
The present report extends the theoretical data of reference 6 for several fuels to”other couibustion pressures ~d inlet-air tezqperatures and thus facilitates the evaluation of experimental data.
The fuels .
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NACA RM E53G14 3 .
considered herein include octene-1, slurry of 50-percent magnesium in octene-1, boron, pentaborane, diboraue, hydrogen, carbon, and aluminum.
b Some exaiples ire given of tke manner In which this theoi%tical informa- tion can be used in the operation of engines and in the evaluation of experimental data.
SYMBOLS The folluwing symbols are used In this report: area, Bq ft A F stream thrust, lb Fn net tnternal thrust, lb acceleration tie to gratity, 32.17 ft/sec2 g sum of the sensible enthalpy end chedcal energy at t~erature
(q
T and at standard conditions, kcal/mole Mach nuIliber molecular weight of a constituent ii mean mlecular weight .
n mniber of moles of a constituent static pressure, lb/sq ft P universal gas constant, ft-lb/(lb)(%) R Sa air specific impulse, lb-see/lb air fuel-weight specific -e, lb-see/lb fuel Sf,w T total temperature, % t static temperature, % velocity, ft/sec v .
w weight flow, lb/see x weight fraction of solids in exhaust gases .
4 NACA RM E53G14 l .- ratio of specific heats r ..
_ -.
efficiency v .
— air specific.impulse efficiency .
‘Sa equivalence ratio; ratio of actual to stoichiometric fuel-air rat10 9(M) stream-thrust correctd.on factor to M Subscripts: a c combustion, conibuetoroutlet Cr crystal e exhaust-nozzle outlet experimental f fuel .
gas “ i denotes ith constituent of combustion products in engine inlet 2 ltqtid 0 solid t theoretical w weight Superscript: * a station having a Mach nw?iber”of unity “ denotes .
ANALYTICAL METHOD Suitable thrust parameters for both theoretical and actual Set- F engine fuel performance have been found to be air specific impulse and r.
NACA RM E53G14 fuel specific impulse, or total stream momentum per pound of air and per pound of fuel, respectively. lkb?specific impulse is defined as (1) where w =Wa+wf “ and fuel-weight specific me Is defined as (2) sf,w “ sJJ30 be ~resaed as Air specific impulse can (3)
‘a=(’+wy
where ~ is an effectlve ratio of specific heats. The net internal thrust of an engine can be determined simply from the relation +X!I (4) ~ in
)
(see ref. 6), where CP(M) is a function relating stream thrust at any ;tation to stream thru& at a station hating a Mach number of unity.
(See eqs. (A2) and (A3) of the appendix.) The significance and the utility of these concepts are discussed in more detail in reference 7.
The theoretical determination of air specific impulse and fuel specific impulse for the fuels considered herein involved two principal steps: (1) The conibustion temperature and burned-product composition were determlned at the assigned ccmibustion pres6ure$ and (2) an isen- tropj.c~ansion h the exhaust nozzle over an ~ansion ratio of 2:1 determined the exkust-nozzle-outlet static temperature and velocity.
The results of step (2) were used to compute air and fuel specific im- pulse.
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6 NACA RM E53G14 The method of computing combustion temperature and composition was - “...
that of reference 8. A set of simultaneous equations was solved which - involved mass balance, heat balance, pressizre,phase changes, and dis- L sociation of solid, liquid, and gaseous molecules. The necessary the& — modynemlc properties of almost all the dissociated and undissociated combustion producte were taken from tables-included in reference 8. An empirical equation given in reference 9 for the specific heat of mag- nesium oxide was used to obtain tabulated values of specific heat~ en- thalpy, and entropy for magnesium oxide; the standard state entropy of d magnesium oxide was taken from reference 10.
E Thermal properties which were required-in setting up the equation of heat balance for the fuels considered herein are presented in table I. - Shown in table 1“1s either the heat of formation, or the heat of combus- tion, or both for.each fuel. By means of the heat of formation or the related heat of combustion, an assigned enthalpy, presented In table 1} was computed for each fuel. This enthalpy was consistent with the arbi- trary base of reference 8. Because of them arbitrary bases, the en-.
thalpies assigned to the fuels give.no Indication of the heat liberated in combustion.
: The following assmnptions were made concerning the combustion pro- — (1) All fuels were pure; (2) cess in order to simplify the analysis: air was composed @.3.78 moles of nitrogento every mole of oxygen; (3) M conihustion inlet-air velocity was negligible so that the combustion static temperature and the combustion total’temperature were eqtij (4) all gases were idealj and (5) ccmibustion was adiabatic and complete, . ~ — that is, chemical equilibrium was assumed. .When solids or liquids were present In the conibustton products, the volume occupied by the condensed materhl. was negligible, and thermal and vebcity equilibrium existed ““ between the different phases.
The woducts of adiabatic conibustion of each fuel which were con- sidered possible in the computations of composition are listed in table 11. They were gaseous except as noted. The posstble formation I of nitrides of boron, mgnesium, and aluminum was neglected because of inadequate thermodpmuic data. For the same reason, dissociation, fusion, and vaporization of magnesium oxide.were neglected.
— The exhaust-nozzle-outlettemperature was determlnedby computing :.
an isentropic expapsion from the cmibustio ntemperature=d pressure over a pressure ratio of 2:1. It was assumed that In the nozzle (1) composition was fixed during the Wansion process, (2) the mlume occupied by condensed materials was negligible, and (3) condensed ma- terials were in thermal and velocity eq@.librlum wtth the gas phase. . . 9 The jet velocity was then calculatedly using the following equation (ref. 11): .
N4CA RM E53G14 7 v= .=294.98/~ (5) ~ The air specdf?icimpulse was then Wf Ve Rte Sa= 1+= —+~ (1 - x) (6)
( )[
g ~ve The jet velocity Ve, determined for an ~ansion ratio of 2:1 in the exhaust nozzle, covered a range of Mach nuu.itiers near unity. The error introduced into the air specific impulse function by assuming a Mach nwiber of 1 for Ve) determined thus, was 0.5 percent or less (ref. 12). The air speclflc impulse was not corrected for this error.
PRESENTATION OF DATA The effects of conibustorinlet conditions upon the theoretical com- bustion performance of the fuels are shown In figures 1 to 8. The flg- ures pertain to the fuels as follows: Octene-l (llq.). . . . . . . . . . . . . . . . . . . . . . . . . . .1 .
Slurry of 50-percent magnesium in octene-1 . . . . . . . . . . . . . 2 Carbon (graphite) . . . . . . . . . . . . . . . . . . . . . . . . .3 .
Boron (cr@. )........ . . . . . . . . . . . . . . . . . ..4 Pentaborane (ltq.)...... . . . . . . . . . . . . . . . . . ..5 Di.borane(lid.)........ . . . . . . . . . . . . . . . . . .6 Hydrogen (llq.) . . . . . . . . . . . . . . . . . . . . . . . ...7 Aludmum(crest.).. . . . . . . . . . . . . . . . . . . . . . . .8 The effect of inlet-air temperature and equivalence ratio or fuel- air ratio upon couibustton performance at a combustion pressure of 2 atmospheres is shown in parts (a), (b), and (c) of each figure. Equi- valence ratios of 0.1 to 1.0 and inlet-air temp~atures of 100°, 500°, and 900° F ~e considered.
For aluminum, data are shown only for inlet- air temperatures of 100° and 500° F.
The variation of conibustion temperature with inlet-air temperature and equivalence ratio is presented in parts (a)3 the varlatlon of air specific impuhe with inlet-air temperature and equivalence ratio is presented in parts (%), and the variation of the reciprocal of fuel- weight specific impulse with air specific impulse and inlet-air tempera- .
ture is presented in parts (c).
Also shown on parts (c) are lines of constant fuel-air ratio.
Reciprocal fuel-weight speciftc impulse has . been used instead of fuel-weight specific impulse to imprcwe reatibility of the curves.
These PEU%S (c) of the figures may he employed to com- pare the performance of different fuels at the same inlet conditions 8 MICA RM E53G14 ..-~ -.
-- as explained in the section Determlnation”of relative fuel-flow require- ments for given engine. Parts (c) cannot,be used to compare the theo- retical performance of a fuel at one inlet condition with the perform- e ance of the same fuel at mother ~t c~d~tla~ since changes in .
inlet-alr temperature are obtained In the free-flylng ram Jet onlyby change in altitude or fll.ght Mach tier. The net t4rust of the engine is then no longer determined by the air specific im se alone, but is also affectedly the changing Inlet condltlon (eq. 4 .
%) A a The effect of conibustion pressure and equivalence ratio on the alr E specific impulse of each fuel except aluminum is presented in parts (d) and (e) of each figure.
Equivalence ratios rangin$ fromO.7 to 1.0 and combustion pressures of 0.2 and 2 atmospheres =e considered at an inlet-air temperature of 100° F. In parts (d), the variation of alr specific impulse with eqplvalence ratio is presented at the two com- .- bustion pressures, and, in parts (e), air specific impulse is presented against the log=lthm of combustion pressure at four equivalence ratios.
Figure parts (e) are useful.in adjusting theoretical alr specific h- pulse determined fo~ any inlet-air temperature to any desired ccmibustion pressure, as discussed h *he section Determination of air specific im- pulse at cozzibustor inlet conditions other than those reported.
ANALYSIS OF DATA .
Octene-1, 5U-pe rcezrt-magnesium slurry, and carbon. - Figures l(a), 2(a), and 3(a) for octene-l, SO-percent-magnesium slurry, and carbon, l respectively, show that a given Increase in inlet-air temperature results in a diminishing gain in corriitlon tempera@zre as eqplvalence ratio is raised. For example, the cdbustion temperature of octene-1 (fig. l(a)) at an equivalence ratio of 0.1 is increased 7+5° Rby raising the inlet- air temperature from 100° to 900° F, while at an equivalence ratio of 1.0, the same increase tn inlet-air temperature raises the com~tlon tezqperatures only 320° R. The elevated comb@tton temperatures occurring at the higher equivalence ratios result in increased specific heats and more dissociation of ccmibustion products. Much of the heat made avail- able by an Increase in inlet-alr temperature is thereby absorbed without a corresponding gain in couibustion temperature.
Since alr specific impulse is a function.of ccm@stion temperature (eq. (3)), the gain in air specific impulse aishieved by a given increase in inlet-air temperature becomes less when eqp.ivalence ratio is raised, as shown in figures l(b), 2(b), and 3(b). Ra@ing the inlet-air tem- perature from 100° to 900° F increased the d.k.specific impulse of .
octene-1 by 24.6 seconds at an equivalence ratio of 0.1, but onlv by -.
7.3 seconds at en eqtlivalence ratio of 1.0 (fig. l(b)).- .
‘-’’wiamu*-* 2x NACA RM E53G14 .
In figures l(d), 2(d), and 3(d), it is shown that the air specific Impulse at a co?ibustion pressure of 0.2 atmosphere is less than that - at a conibustion pressure of 2 atmospheres within the range of equivalence ratios shown (O.; to 1.0). Moreover, the loss tn alr specific impulse tith this decrease in mdmstion pressure is greatest at the richer A decrease in couibustion pressure shifts the chemi- equivalence ratios.
cal equilibrium among all the couibustion products toward the condition of more dissociation. The resulting absorption of thermal energy lowers the air specific impulse. S1.ncedissociation becmes greater at the % higher combustion temperatures associated with richer equivalence ratios, m F’ the loss in air specific impulse with luwered ccmibustion pressures be- comes more serious as equivalence ratio is raised.
Although the data of figures l(e), 2(e), and 3(e) were computed for only two combustion pressures, a straight J3ne of air specific @pulse against the Iogsrithm of cozibustion pressure for each equivalence ratio has been drawn between combustion pressures of 0.2 and 2 atmospheres.
For fixed ~ansion ratios and equivalence ratios, the theoretical im- pulse v~g of a rocket Wies veryne~~ ~~~~ththe ~g~ithm This semilogarithmic re- of chsziber pressure as shown in reference 13.
lation Is e.xLended herein to ram-set air specific impulse against com- bustlon pressure. As a verification, atr specific impulse at an equi- $ valence ratio of 1.0 was computed for octene-1 at two additional com- These data are represented bustion pressures of 0.6 and lo atmospheres.
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This semilogsrithmic relation on figure l(e) by the circled points.
between air specific impulse and couibustion pressure is ~ected to be . valid for allleight fuels reported here at equivalence ratios from 0.7 Extrapolation of the hes from 2 to 10 atmospheres combustion to 1.0.
pressure is less satisfactory than interpolation between 0.2 and 2 atmos- pheres. All lines have therefore been shown broken above 2 atmospheres.
Mron, pentaborane, diborane, and hydrogen. - These fuels comprise a seauence In which boron is ccmibined with Increasing percentages of One of the couibustion products, boron otide, vaporizes be- hyti”gen.
tween 3000° and 3S00° R, tith a loss in ah specific impulse resulting from heat absorption. In the following table are shown the mle frac- tions of boron and hydrogen in the fuels and the approximate heat ab- sorbed by vaporizing the boron oxide formed from a puund of each fuel.
Also shown is the approximate heat absorbedby vaporizing the boron For con- oxide formed from a pound of stoichiometric fuel-air mtxture.
venience, these heats of vaporization have been evsluated at a tempera- ture of 3240° R.
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10 -- NACA RM E53G14 *.
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Fuel Mole fraction of Heat absorbed by constituents vaporization of boron oxide Boron Hydrogen Btu/lb Btu/lb stoichio- fuel metric fuel-air mixture Boron 1.0 0 5314 503 Pentaborane .357 .643 4551 323 .250 Diborane .750 4J.53 261 Eydrogen o 1.00 0 0 —.. .— As the amount of boron in the fuel decreases, the heat absorbedby vapor- — .- ization of boron oxide also decreases. ‘- Comparison of figures 4(a), 5(a), and 6(a) shows irregularities in the curves of combustion temperature againstr.~quivalence ratio, beginning at about 3000° R, caused by vaporization of the boron oxide.
The irregu- larities become progressively less severe as the hydrogen content of the fuel is raised, because of.the decreasing smtint of heat absorbedby ““ vaporization of boron oxide.
The effect of this vaporization on the .
thrust performance .of the fuels is shown in figures 4(b), 5(b), and 6(b) (variation of air specific impulse with equivalence ratio and inlet-air.
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temperature) and in”figures 4(c), 5(c), and G(c) (variation of reciprocal fuel-weight specific impulse with air specific impulse and inlet-air tem- perature). It is ti interest to compare the reciprocal fuel-weight specific impulse (fuel consumption) of these .fuelswith that of octene-1 (fig. l(c)) at levels of air specific impulse below and above the vapor- ization region of boron oxide.
For”ievels of eir specific impulse less than 140 seconds and at any inlet-air temperature, a higher reciprocal fuel-weight specific impulse (greater fuel consumption) is experienced with octene-1 than with boron, pentaborane, & diborane.
At air specific impulses exceeding 140 seconds, octene-1 actu811y shows a lower fuel- welght specific impulse (less fuel consumption) than boron, for any — .- inlet-dir temperature. While the reciprocal ~el-weight specific im- pulses of both pentaborane and cllborane rise ~harplyat an air specific .- impulse of about 140 seconds, their fuel consumption remains lower than that of octene-1 at all levels of air specifi~ impulse. At an eqdva- — .— lence ratio of 1.0, boron, as well as Mborane and ~entaborme, provides .
a higher air specific impulse than octene-1 (figs. 4(b), 5(b), and 6(b)).
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Id NACA FM E!53G14 .
It is shown in figure 4(d) that the air specific impulse of boron at an equivalence ratio of 1.0 is raised 5 seconds by increasing the This, the largest gain .
conibustion pressure from-O.2 to 2.0 atmospheres.
~eriencedby any of the fueh considered herein, results from sup- pressing the dissociation made possible by the high cmnbustion tempera- ture of boron.
Liqtid hydrogen has by far the lowest reciprocal fuel-weight speci- fic i-e (lowest fuel consumption) of any of the fuels considered herein, at any level of air specific impulse (fig. 7(b)). Despite its outstanding couibustion properties, liqtid hydrogen does not appear prom- is~ as a r-am-jetfuel because of its low liquid density (ref. 6) and difficulties of handling and storage.
Aluminum. - Aluminum produces an otide which vaporizes at elevated tempe~ ~s vaporization has an adverse effect on the couibustion performance of alumiuum, as the irregularities in the curves of fig- ures 8(a) to (c) indicate.
APPLICATIONS CR?DATA M se at combustor inlet conditions Determination of air specific @ul know the other than those reported. - In many instances it is desiredto air specific impulse at inlet conditions other than those for which the A~roximate values of air specific data of figures 1 to 8 were computed.
impulse at other inlet conditions maybe determined as follows: .
At the lower equivalence ratios (below 0.7) the effect of pressure The sir specific impulse at these lower equiva- is usually negligible.
lence ratios can be read directly from the curves of air specific im- pulse against eqyivslence ratto and Inlet-air temperature (Parts (b) of the figures) without consideration of corfibustion pressure. An exception to this srises with materials containing boron, where the vaporization of boron oxide in the vicinity of an equivalence ratio of 0.4 is pressure dependent. A direct computation is then necessary.
At equivalence ratios exceeding 0.7, the effect of conibustion pres- sure upon air spectiic impulse becomes important for all fuels. The effect of combustion pressure on air specific @mlse in this region can The air specific impulse at the be determined in the following manner: desired inlet-air temperature, determined from psrts (b) of the figures, is entered in parts (e) at a pressure of 2 atmospheres. The W specific impulse is then corrected to the desired pressure along a J3ne of con- .
stant composition (constant equivalence ratio). For exuple~ the ah 12 NACA RM E53G14 .
specific impulse of boron at an equivalence ratio of 0.8, an inlet-air - temperature of 800° F, and a combuation pressure of 0.3 atmosphere can — be found as follows: From figure 4(b) the air specific impulse is i determined as 182.6 seconds for the conditions stated, but at a com- — bustion pressure of 2 atmospheres. The value obtained is entered In figure 4(e) at this pressure and air specific impulse (point A), and a line of constant composition is followed to a pressure of 0.3 atmos- phere (point B).
The desired air specific i.urpube is found to be 178.8 seconds. This is very close to the value of.178.83 seconds determined by direct computation for a pressure of 0.3 Qtmsphere.
Fil-
In making a pressure correction, it maybe necessary occasionally to enter data in a figure such as 4(e) at an & specific impulse exceed- tng the highest line of air specific impulse against conibustion pressure.
For example, figure 4(b) Indicates an air specific @pulse of 190.5 sec- onds for an equivalence ratio of 1.0, an inlet-air temperature of 900° F, and a combustion pressure of 2 atmospheres.
A point C is thus located on figure 4(e) which is above the highest line already present.
A cor- rection to a combustion pressure of 0.2 atmosphere, made along a dashed line converging toward existing lines at the ssme rate with which they converge toward each other, locates an air specific impulse of 184.6 sec- onds at point D. By direct computation, tkL~e sought is found to be 184.7 seconds.
Determination of air specific impulse efficiency and conibustion .
efficiency. - Both air specific impulse efficiency and conibustion effi- ciency may be found for experimental data by the use of curves presented .
herein. Air specific impulse efficiency is defined as the ratio of the ~rimental air specific impulse to the theoretical air specific im- pulse at the same equivalence ratio:
*
*a,t ~ @ constant) (7) l-lsa =
()
The experimental air specific impulse must be.computed from experimental measurements as discussed in.the appendix~ the theoretical air specific iqpulse Is read from the curves of air specific impulse against equiva- lence ratio at the burner-inlet temperature appmng to the ~erimental.
data. It may thenbe correctedto the conibustion pressure used in the actual.engine by the method described previously.
A codn.u!tion efficiency which is often useful can be defined as the ratio of the theoretical equivalence ratio to:the experimental equiva- lence ratio required to produce a given ab specific impulse: .
q (Sa constant) (8) 7= = *— eq Sa
()
NACA RM E53G14 u .
deftnitton is valid Ilzel-airratios maw replace equivalence ratios. This when the e~erimental data ox for equivalence ratios of 1.0 or less.
pressure correction are obtained at premures other than 2 atmospheres a ~ be conveniently applied to the theoretical equivalence ratio as follows: The ~eri.mental air specific impulse and conibustlon pressure are entered on the semllogarithmic graph of theoretical ah specific im- pulse against combustion pressure (parts (e) of the ftgs.), and a line of constant composttton is followed to a conibustton pressure of 2 atmos- pheres. The & speclflc impulse, ad@sted to the 2-atmosphere standard, and the ~erimental inlet-air t~erature are then used on the plots of air specific impulse against inlet-air temperature and equivalence ratio to find the theoretical equivalence ratto. For exsmple, boron burned at an inlet-air temperature of 500° F, a conibustion pressure of 0.2 atmos- phere, and an equivalence ratio of 1.0 produces an ~erimental air specific fmpube of 180 seconds, which locates point E on ftgure 4(e).
Following the dashed MIS of constant composition to point F determines a pressure-adjusted air specific -se of 184.9 seconds. Locating a point in figure 4(b) at 184.9 seconds and at an inlet-air t~erature of -o F determines a theoretical equivalence ratio of 0.885. A combustion efficiency of 0.885 is then found bymesns of equation (8).
Determination of relative fuel-flow requirements for given engine. - IQ instances where several fuels are being considered for an engine, it may be desired to know the relative amounts of each fuel required to ob- tain a fixed thrust level. The curves of air specific impulse against reciprocal fuel-weight specific impulse may conveniently be used for determining the smounts of ftzelif advantage is taken of the following assumptions: The ccmibustion efficiency is the same for each fuel, and momentum and other internal pressure losses sre nearly the ssme for each fuel at a given thrust level.
For exazqple,a ram-jet engine is operate& wtth octene-1 or any other reasonably similar hydrocarbon at a fuel-air ratto of 0.05, an inlet-ah temperature of no F, and a conibustion pressure of 2 atmospheres. l?kau figure l(c), the air specific impulse for octene-1 at this fuel-air ratio and inlet-air temperature is 153.4 seconds~ the reciprocal fuel-weight specific impulse is 0.000326 seconds-l.
By use of the curves (fig. parts (c)) of reciproc~ fuel-weight specific impulse against air specific im- pulse for the other fuels at an inlet-air temperature of 100° F, fuel-sir ratios, reciprocal fuel-weight specific impulses, and relative fuel flows required to produce an air specific hpul.se of 153.4 seconds sxe titer- mined. They are presented in the followlng table: NACA RM E53G14 Fuel-air Reciprocal fuel-weight Fuel Relative ratio specific .~lse, Oec-l fuel flow Octene-1 0.05 0.326X10-3 1.00 50-Percent- .065 .423 1.30 magnesium slurry 3oron l 054 .353 1.08 Pentaborane .042 .274 .84 Diborane .038 .247 .76 .
The relative fuel flcnicam be defined in this case as either the ratio of the reciprocal.fuel-weight specific impulse of the substitute fuel to .—.
that of octene-1, or the ratio.of the fue~-iilr ratio of the substitute fuel to that of octene-1, since, at a constsnt air specific impulse, the fuel-weight specific @pulses of two fuels &re in the ratio —. —.
Wf Sf,wl 7 z (J —.
= .
(9) Sf,wz Wf =1 .- () .
(seeeq. (2)).
A correction”mf fiel-air ratios for ccmibustIon pressures other than 2 atmospheres canbe made in the manner previously described for equi- valence ratios used to determine combustion efficiency.
CONCLUDING REMARKS The effect of inlet-air temperature, co?ibustion pressure, and equi- valence ratio upon theoretical air specific ,hpulse performance was inves- — tigated for the following fuels: octene-1, m-percent-magnesium slurry, - boron, pentaborane,. dllorane, hydrogen, carbon, and aluminum. Considered -.
were inlet-air temperatures from 100° to 900° F at a conibustion pressure of 2 atmospheres and a conibustion pressure of 0.2 atmosphere at an imlet- — — air temperature of “100°F.
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NACA RM E53G14 .
The benefit to air specific impulse of an increase in inlet-air temperature was observed to decrease at higher equivalence ratios, be- cause of increasing specific heats and dissociation of the couibustion products resulting from higher combustion temperatures. The fuel con- sumption of pentaborane and dtborane remained below that of octene-1 despite the adverse affect of boron oxide vaporization on the performance of boron-containing fuels at combustion temperatures exceeding 3M1° RJ the fuel consumption of boron became higher than that of octene-1 above this temperature. The & specific impulse performance of boron, di- borane, and pentaborane exceeded that of octene-1 at high equivalence ratios. An increase in conibustion pres6ure from 0.2 to 2.0 atmospheres caused gains in air specific impulse at higher equivalence ratios of as much as 5 seconds.
Because a Mmited range of inlet-air tempera~es and ccmibustion pressures were considered, methods of extending the data to other tnlet conditions were presented. Determination of air specific impulse effi- ciency and combustion efficiency for ~erimental combustion by means of the theoretical data herein was discussed. The use of the theoretical performance data in determining the relative flows of the various fuels to an engine operating at a fixed thrust level was elso discussed.
Lewis Flight Propulsion Laboratory National Advisory Committee for Aeronautics Cleveland, Ohio, JWy 14, 1953 NACA RM .
AEPENDrx - COMITJTATIOIV OF AJR SPECIFIC J31K%GSE FROM — l EXPEKU@NTAL DATA The determination of air specific iqpulse efficiency requires that the experimental air specific impulse be computable. Suitable measure- ments of pressure, drag, end thrust must be made on the e~erimental — -.
engine or combustor to permit computation of the stream thrust at the .
end of the exheust nozzle: d % N Fe = PA+:e (Al) — () This equation Is then reduced to the stream thrust function at a conti- .
tion of sonic flow (A2) .- where (A3) .
‘(%) ‘./+
“ The e~erlmental air specific impulse is then (A4) The Mach nuuiberat the exhaust-nozzle outlet .
csm be estimated from the — equation ‘gJ eve (Aq - %= re8PeAe ,
r
For convenience, ~(~) may be found ffim tables 30 to 35 of refer- ence 14 as the term F/F*.
The expression 9(M) Is rektively insensi- tive to T, in the nei”&iborhood of M equal to-l, as shown in-the follow- ing table: .
.
.- NACA RM E53G14 .
T F/F l = ~(%)
--i .
1.4 1.1 1.0599 1.0451
G
.8 1.0231 1.0185 .9 1.0051 1.0034 1.0000 1.0000 1.0 1.1 1.0041 1.0030 1.0108 1.2 1.014S 1.3 1.0305 1.0217 (A5), then It must be observed that if l& is determined by equation the error h ye, will ex- ~(~)s resUlt~ from an ticorrect choice of y teed that shown h the preceding table. Data in reference 3 show that a ~ at him combustIon temperatures (or high air satisfactcmy value of T specific impulse) would ~e 1.2 to 1.3J at low air specific impube or cored bustion temperature, values of 1.3 to 1.4 can be employed.
.
.
HEKERENCES 1. OISOUJ Walter T., and Gibbons, Louis C.: Sta- of Cc@ustion Research on High-Energy Fuels for Ram Jets. ltACARM E51D23, 1951.
2. Lord, Albert M.: ~ ~nt~ ~v-ti-tl~ of the c-st~n ~0- perties of a Hydrocarbon Fuel and Several Magnestum and Boron Slurries. NACA RM E52B01, 1952.
3. Tuwer, Leonaxd K.: Effect of Water Vapor on Co?ibustionof Magnesium- Hydrocs&bon Slurmy Fuels in a Small-Scale Afterburner. IACA RM E52H25, 1952.
4. Gibbs, James B., and Cook, Preston N.~ Jr. : Preparatim and Physical Properties of Metal Slurry Fuels. KACA RM E52A23, 1852.
5. Branstetter, J. Robert, Gibbs, James B., and Kaufman, Warner B. : Magnesium-Slurry ConibustionPerfo~ce in 6.5-Inch-Diameter Ram- .
Jet Engine Mounted in Connected-Pipe Factllty. NACA RM E53E27, 1953.
NACA RM E53G14 .
6.
Breitwieser, Roland, Garden, Sanford, and Gemon, Benson: Summary . .
Report on Analytical Evaluation of Air and Fuel Specific-Uzpulse Characteristics of Several Nonby&ocerbon Jet-Engine Fuels. NACA .
RM E52L08, 1953.
7. Rudnick, Philip: Momentum Relations in Propulsive Ducts. Jour. Aero.
Sci., vol. 14, no. 9, Sept. 1947, pp. !540-544.
.— 8. Huff, Vearl N., Gordon, Sanford, and Mortiell,Virginia E.: General ~ d Method sad Thermodynamic Tables for Ccmtputation of Equilibrium m N Co~osition and Temperature of Chemical Reactions. NACA Rep. 1037, 1951. (Supersedes NACATN’s 2113 and 2161.)
9. Perry, John H., ed.: ChemiceJ Engineers’. Handbook. Third ed., McGraw-~11 Book Co., Inc., 1950.
10. KelJ.ey,K. K.: Contributions to the Data on Theoretical Metallurgy.
IX. The Entropies of Inorganic Substances. Bull. 434, Bur. Mines, 1941.
U. Huff, Vearl N., Calvert, Clyde S., and Erdmann, Virginia C.: Theo- retical Performance of Diborane as a Rocket Fuel.
NACA RM E8117a, 1949.
.
12. Gammon, Benson E.: Preliminary Evaluation of the Air and Fuel Specific-Impulse Characteristics of Several Potential Ram-Jet Fuels. I - Octene-1, Aluminum, and Aluminum - Octene-1 Slurries.
.
NACA RM E51C12, 1951.
13. Gordon, Senford, and Huff, Vearl N.: Theoretical Performance of Liquid Hydrazine and Liquid Fluorine as a Rocket Propelhnt. NACA — RM E53E12, 1953.
14.
Keenan, Joseph H., and Kaye, Joseph: GEL@Tables-Thermodynamic Pro- perties of Air, Products of Conibustion and Component Gases, Com- pressible Flow Functions. John WUey LSSons, Inc., 1948.
15, Smith, Marion L., and Stinson, Karl W.: Fuels and Cdibustion.
McGraw-Hill Book Co., Inc., 1952.
16.
Rossini, l!&ederick D., et al.: Selected Values of Properties of Hydrocarbons. Circular C461, Nat. Bur. Standards, Nov. 1947.
17 l RossiniJ Frederick D.} et al.: Selected Values of Chemical Thermo- C500, Nat. Bur. Standards, Feb. 1952.
-C R’Operties. Circular .
IOWA Bbi E53G14 19 18. Beckett, C. W., Clarke, J. T., and Johnston, H. L.: Tentative Thermal Ftmcttons for Diborane. Joint Rep. 7 on Proj. 319 and .
Rep. 4 on Proj. 309, Ohio State Univ. Res. Foundation, Aug. 1, 1948. (USAF Contract W33-038-ac-17721 and ONR Contract H60nr- 225, T. O. IX, NR 058 061.)
19. Woolley, Harold W., Scott, Russell B., and Brickwedde, F. G.: Com- pilation of Thermal Properties of ~drogen in Its Various Isotopic and Ortho-Para Modifications. Nat. Bur. Standards Jour. Res., vol. 41, no. 5, Nov. 1948, pp. 379-475.
.
.
.
.
TAPU I. -mEmALEwEmIES oF8g16FlJEEl Ee03t of Ccdnlutid+ Fuel Fcmmlla Phaee TeIqyk% - of fcn’mltlim,
-@- w- -~
kc@ole Cdhletim
“???
plvdllcts kc+ole b,~.~ 18,889 octane-l cfy~ IQlid 298.I.8 1285.28 (w)gJ (%4 I&20 4.8M8Z Mg Cqwwi s41.56 50-PaCent- 288. ld %ote (l@o)@ (WJg + c$~ -~~ (q)g J B 288.I.8 %.0 %1.o 25,104 (B20TJ)= 17s.5.6 288.lG 22,127 Pentamlntla ‘%.8 %022.9 (E@)g, (Ws)m %%. ~- -“~ lM.63 Llqpid %7B.1 S.)021 (lx#)& (%#3)= =7.8 -- > ‘%s.m3 87.64 My ~>~ (E@g ,2Q*= c 288.18 ‘%.0 ‘%4.C62 U,087 82.18 (202)8 (%% r“ Al Crystal 288. = %0 ‘%29.545 2s4.70 ~,= ‘(%05)= .
%fexence -M. - At of f-tam of Hg * referemce 17.
bf!tveen 180.6p ad 268.18° K tram refelwlce 18.
@eat Of vaPoKLa&kxI md enthalPY &WI&I beiiumem 20.22° ad 298.l@ K fma refemme 18.
~.
.
.
, & -mz , , .
NACA RM E53G14 l!AmE II. -PROIUC51!SC0.WE~-~A6 ARESULT OF ADIABATIC cm3usTlDlr k-tam-l x x x x x x x X x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x
is=
--3
%aEmc4W except aE Ilutea.
NACA RME53G14 .
.
5ooo- - Ho Inlet-ah II OF .
2000 ~ .
0 .2 .4 .6 .8 1.0 Equivalence ratio, @ (a) Variation of conitw.etion temperature with equivalence ratio and inlet-air temperature. Conibu”tion pressure, 2 at~spheres.
Figure 1. - Effect of rem-jet conibuetorinlet conditions on theoretical ccmibuetion performance of liquid octene-1.
.
..
NAOA RM E!53G14 .- blet-air OF .
.
o .2 .4 .6 .8 1.0 Equivalence ratio, @ (b) Variation of atc specific Impulse with inlet-ah temperature and equivalence ratio. Co?ibustionpressure, 2 atmospheres.
.
Figure 1. - Continued. Effect of rem-~et ccmtmstor inlet condi- tions on theoretIcal cmibustion performance of liquid octene=l.
NACARME53G14 .
. 44cLo-~ .
8toichlmmtrLc \l .40 \ \ 0.0678 } .36 / / { ‘ .02 ~ .32 / .$ ‘.05 \ ) a .28 d s.
\ $ f-l i a- .24 u lm .
; / .20 - i l b !
3 { / + .16 / ‘.a?
/ \ j .U - / i .
.02 / .c4- 120 140 160 180 60 20 100 zoo * Ah Epecific impuhe, Sa, lb-eec/lb am (c) Vcmiatlon of reciprocal --weight epaciflc Iq7ulee with air epeciflc impulee .
d inlet-air t6nperature. Contbuetion preeeura, 2 l tnmepheran.
ram-~etcodbuetar inletcomlitione on theoretical Figure1. - Continued.Effectd Colblletion perf~ e of liquidoctene-1.
4x NACA RM E53G14 .
170tH5zd=l
.— - I 1 1 I I I 15U r
i!
.7 .8 .9 1.0 Equivalence ratto, 0 (d) Variation of ah specific Impulse with com- bustion pressure and equivalence ratio. Met- ati temperature, 100° F.
Figure 1. - Continued. E&fect or ram-jet ccmibustorInlet condltlona on theoretical com- bustion performance of llquld octene-1.
.
NACA RM E53(314 , .
I I I Equivalence o 1.0 - --- -- --- ~ -— 9 - - - > 164. - —“ a m I o AIMitional data —aeterldndby ’” direct computa- 0?
tion J 160 m ---- -- — .8 9 - ~ 1 — — — — .
~ 156 i m .
.7 -——. -—- -— .
148.
.2 .4 .6 .8 1 2 4 6 8 10 Combustion pressure, atm (e)Variation of Eti speclf Ic hpulse with coinbuetlon pressure at selected equivalence ratios. Inlet-ahtaqperature, l(X1° F.
Effect of raukJet ccmibuetor inlet conditions on thee- Figure 1. - concluded..
retical combuetlon perfornwE e of liquid octepe-1. — .
.
NACA RME53G14 .
moo Inlet-ah tempe ature, % .
— 900 .
I .2 .4 .6 .8 1.0 “ Equivalence ratio, @ (a) Variation of codbustlon temperature with equivalence ratio and inlet-air temperature.
Combustion pressure, 2 atmospheres.
Figure 2. - Effect of ram-~et conibustcm Inlet conditions on theoretIcal comhusti.on performance of 50-percent-ms&nes ium slurry.
NACA RM E53(314 .
.
z
r Inlet-air -, OF Uo .
. , # 900 f
$!
500 { -.
0 .2 .4 . .“6 .8 1.0 Equivalence ratio, 0 (b) Variation of air specific impulse with inlet-air temperature and equivalence ratio. Wmilmstlon pressure, 2 atmospheres.
Figure 2. - Continued.
Effect of ram-jet ccmibustor inlet conditlone on theoretical combustion performance of 50-percent-magnesium slurry.
.
NACA RM E53G14 .70X10-3
1 I I I I I I 1 I I I
I !
FueLair ratio l Btolchiometric I I I
\
o.1.137
Ad
Alr specific iqpulse, Sa, lb-see/lb alr (c)V=iation of reciprocal fuel-weight epecflic Iqwlsewith alr specific -se W Inlet-air temp-ature. Conbuetion pressure, 2 atmepheres.
Figure 2. - continued .
Effect of rem-~et conibuetorinlet condltlone on theoretical.comibuet ion performance e of 50-percent-magnesium slurry.
NACA RM E53G14 l Ccmhmtion pressure, atm I2.0/ ‘ .
$!
.
I 1 I I I UJ 1 .7 .8 .9 1.0 Equivalence ratio, 0 (d) Variation of air specific impulse with com- bustion pressure and equivalence ratio.
Inlet-alr temperature, 100° F.
Figure 2. - Continued. Effect of rem-~et combustor Wet conditions on theoretical combustion performance of 50-percent- _esim slurry.
.
.
l . .
NACA RM E53G14 b .
h MO I I I II
0?
I I I I I Ill
i!
. n .
164 — I ~ “
I I I I I
I 2 .4 .6 .8 1 2 4 6 8 10 Ccmibu8tion ~eaaure, atm (e] Variation of alr npeclflc impulse with cmibuetion pressure at selected equivalenceratios. Inlet-ah temperature, 100° F.
Figure 2. - Concluded. Hfect of ram-~et conibuetor inlet codltions on theo- retkal combuetlon performan ce of 50-percent-megnesim elurry.
32 NACA RM E53G14 .
Iillet-air ‘ / .
.
f 0 .2 .4 .6 .8 1.0 Equivalenceratio,0 (a) Variation of conbuetiontemperaturewith equivalence ratio and Inlet-alrtemperature. Combustionpressure, 2 atmospheres.
Figure 3. - Effect of rem-~et cxmibuetor Inlet condition on theoretical. comhuetlon performanceof carbon (graphite).
5X NAOA RM E53G14 33 h .
l-l g N o l 2 .4 .6 .8 1.0 Equivalence ratio, @ (b) Veris.tlonof air specific Impulse with equivalsme ratio and Inlet-air temperature. Conibustion pressure, 2 atmospheres.
Figure 3. - Continued. Effect of ram-~et conibuetorinlet con- dit tons on theoretical combustion performanc e of carbon (graphite).
NACA IME53G14 .
.
iij .
Air specific impulse, SE) lb-oec/lb alr (c)Variatlonofreciprocal fuel-weight specific Iq@sewith air speclflc Iqmlse and Inlet-alr temperature.Combustion pressure, 2 atmospheres.
Figure ?i.- Continued. EMect of rankdet caubustor inlet conditions on theoretical combuetIon performance of carbon (graphite).
.
.
NAC.A RM E53G14 .
170.
colIibustor Ji pressure, .
2.0 .
$!
.
I .7 .8 .9 1.0 Equivalence ratio, 0 (d) Verlation of ah specific impulse with com- bustion pressure and equivalence ratio.
Inlet-air temperature, l~” F.
Figure 3. - Continued.. Effect of ram-~et combustor inlet conditions on theoretical codbustion performance of carbon (graphite).
.
.
NACAEM E53G14 .
.
168- .
+ + Equivalence .
/ +- ratio, - - ~ ~ ~ “ — 164 _ ~ — -- a .9 — - ~ 160 ~ — — — — — — — — — — — — — — — — a m ; - md ; 156 ——- -—- — .8 !
, : 152 } .
.7 ———, —— .
6 8 10 combustion pressure, ah (e) Variation of alr specific impulse” with caibuetion pressure at selected equivalence ratloa.
Inlet-air temperature, 100° F.
Figure 3. - Concluded.
Effect of ram-~et combuetor inlet conditions on theo- retical combustion performance e of carbon (graphite).
.
.
NACA FM E53G14 6000“ Inlet-air lm o .2 .4 .6 .8 1.0 Equivalence ratio, @ (a) Varlatlon of cmibuetion temperature with equivalence ratio .
and Met-air temperature. ConibuEt ion pressure, 2 atmospheres Figure 4. - Effect of rem-jet combuetcm inlet condition on theoretical conibuetlon performance of crystalline boron.
NACA FM E53G14 l 20C .
16C — 14a / Met-air temperature, + — / MC r / / 10C / 8C .4 .8 1. 0 .2 .6 Equivalence ratio, @ — Variation of air specific @ulse with inlet-air temperature and equivalence ratlo. Combustion pressure, 2 atmospheres.
l Figure 4. - Continued. Effect of ram-jet combuetor inlet conditions on theoretical combustion performance of crys- . .
talline boron.
NACA RM E53G14 .
~~-3 Fuel-ah u a!
m .09 hlet-dr “ .07 temp~ature, a- ‘.06 I =1 I I I / “-.03 t 3 100 120 140 160 Iao 200 Alr specific @ul.ee, Sa, lb-see/lb ah (c) Variation of reciprocal fuel-weight specific impulse with air sp@flc Iqpulse and Inlet-air t~erature. Conibuetionpressure, 2 atmm@u3re8.
Figure 4. - Continued. Effect of raw$et cmbuetor inlet condition on theoretical combustion performance of crystalline boron.
NACA I&fE53G14 b .
I CombustIon atm 2.0 .7 .8 .9 1.
Equivalence ratio, @ (d) Vsriation of air specific impulse with combustion pressure and equivalence ratio.
Inlet-air teqerature, 100O F.
Figure 4. - Centinued.
Effect of ram-~et ccmibustor Inlet conditions on theoretical combustion performance of crystalline boron.
.- l .
6X NACA EM E53G14 .
.
d m ml
i!
6 8 10 Combuetlon preseure, ah (e) Variation of air specific impulse with conibuetlon pressure at selected Inlet-air teqerature, 100O F.
equNelence ratios.
Effect of r~~et conibuetor inlet cotiltlone on theo- Figure 4. - concluded.
e of cryetelline boron.
retical combuet ion performance .
.
NACA RM E53G14 .
Inlet-air temperature, OF 20CKI 500 a f 1000 I o .2 .4 .6 .8 1.0 Equivalence ratLo, @ (a) Variation of.conhetion tenrperature with equivalence ratio and Inlet-alr temperature. Combustion pressure, 2 atmospheres.
Figure 5. - Effect of ram-Jet combuator inlet conditions on theoretical combustion performance of liquid pentaborane.
.
.
.
Lnlet-alr temperature, OF 1.20 900 ‘ .2 .4 .6 .8 1 Equivalence ratio, @ (b) Variation of air specific impulse with Inlet-air temperature and equivalence ratio. Combustion pressur~ 2 atmoepherea.
Figure 5. - Conthued. Effect of ram-jet conibustorInlet condltione on theoretical combustion performance of liquid pentaborane.
44 NACA RM E53G14 ___ .-— rlldair ratio .
.40 .36 .’32 .
— .28 .
Inlet-alr % 100 .24 - .
.
\ .20 v .
} -.
.16 /~ .
/ / , A .12 .
{ / .W + .O1 / ..
--- — 80 lW 120 MO 1s0 lso 200 liir epecific imgwlee, S~, lb-see/lb air .
(c)Variation of reciprocal fuel-weight spec~ic impihe withair specific .
Ccmbudion~eOsure, 2 atm@eres.
we d inlet-n-temperature.
‘cfram-Jet canbuator inletwnditionnau F-e 5. - continued.Effect theoretical ccmbuetion performance e d IJ.quid pentaborue.
. .
NAOA IM E53G14
““rrrrrrl
!
Combustion atm 2.
f!
I I I I 1-$’”-1
. 8 .9 1.
.7 Equivalence ratio, 0 (d) V=l.ation of air specific impulse with com- bustion pressure and equivalence ratio. Inlet- air temperature, 100° F.
Effect of rem-jet ccmihwtcm Figure 5. - Contdnued.
inlet condition on theoretical ccmhetion per- formance of liquid pentaborane.
l .
NACA RM E53G14 .
.
..- 192- ratio,
I I o I I L---l
4-
.
-- -- -- .
— - — 2 4 .2 .4 .6 .8 1 Conibuetlon pressure, atm (e) Varlatlon Or air specific @ulse with codmetion preesure at selected .- .
-.
equivalencerat10s. Inlet-air temperature,10& F.
.
Figure 5. - Concluded. Effect of rem-Jet cambuetor inlet condltlone on theo- retical combuetlonPerf=-ce of llquld Petitaborane.
.
NACA RM E53G14 .
6000 ‘ 5000 — — — — — — — — ?sOL?Q ~e&fi “ temperature, l OF .
.
2000 — 100 f 0 l 2 .4 .6 .8 1.0 Equivalenceratio, O (a) Verlatlon of combuetlontemperaturewith equivalenceratio and inlet-airtemperature. Cmibuetionpressure, 2 atmos- pheres.
Met conUlt ione on Flgu.me 6. - Effect of rem-Jet cmiketor theoreticalcombuet Ion performance e of liquid diborane.
NACARK E53G14 .
.- .
v’ ‘“
1.20 *“” 0 .2 .4 .6 .8 1.0 Equivalence ratio, ?
(b) Variation of stirspecific impulse with inlet-air temperature and equivalenceratio. Ccmibuetion pres.
sure, 2 atmcmpkres.
.
Figure 6. - Continusd. Effect of ram-Jet combustor inlet con- ditions on theoretical combustion perfqce of Mquid diborane. .
7x NACA RM E53G14 .
(C) VuAetion of reciproc~ W-~@t epecflfi -se ~th * ~Pec~lc Conibuetion pressure,2 a~ep~~.
-e ed inlet-alrttellperatwe.
Figure 6. - Continued. Effect of ra5-Jet cmibuetor inlet condltloneon theoreticalcmibuetlonperformanceof liquid diborene.
NACA W E53G14
““rrrrrll
I Combustion presmre, / atm
I
2.0
5!
I I I I I I 160 I 1.0 .7 .8 .9 Equivalence ratio, 0 (d) Variation of air specific Impulse with com- -—— bustion pressure and equivalence ratio.
.
Inlet-air temperature, 100° F.
Figure 6. EHect of rem-jet - - continued.
combustor inlet conditions on theoretical combustion performance -of liquid dlborane.
NACA RM E53G14 .
‘l=mI
Equivalence I I ...— .— ..- ) Combustion preesure, atm (e) Variatton of alr epecfiic impulee with combuetton preseme at eelected equivalence ratioe. Wet-ah temperature,M@ F.
Effect of ram-jet couibuetor Inlet condition on theo- Figure 6. - Concllded.
retical conibuetion performance e of liquid diborane.
.
.
NACA FM E53G14 .
— { w / .
.2 .4 .6 .8 1.0 Equivalenceratio, O (a) Varlatlon of coibuetiontemperaturewith equl.valence ratio and inlet-airtemperature. Conbuetionpressure,2 atm8- pheres.
Figure 7. - Effect of ram-:et combuetorinlet condltionaon theoreticalcombustionperformanceof liquld hydrogen.
RM E53G14 .
20C l MC 16C 14C 12c 10C W .2 .4 .6 .8 1.0 Equivalence ratio, @ (b) Variation of ati specific impulse with Inlet-air temperature and equivalence ratio. Cwibustion pressure, 2 atmospheres.
Figure 7. - Continued.
Effect of ram-$et combustor Inlet con- ditions on theoretics conibust ion performance of llquid hydrogen.
\ NACA RM E53G14 W d .
v.. .
.Wlo-s l N co 0) .16, r rJ — ~ .
$ .U2 A 0’ Inlet-air i .10 $ # .08 $ $!!
$ .06 & z Ui — .04 / l m 80 100 120 140 -.”160 180 200 Alr specific impulse, 8a, lb:6ec/lb 8fi (c) Variation of reciprocal fuel-weight specific impulse with alr spectiic Im@.se and inlet-air temperature. Cmnbuetion pre~sure, 2 atmomphereB.
.
Figure 7. - Conttiuea. Effect of ram-Jet ccxiimstor inlet conditions on – theoretical combuetIon performance of liqwl.dhydrogen.
NACA RM E53G14 .
.
d a m ml 1 1 , I t Combustion pressure, atm r w .
I I I I
.7 .8 .9 1.0 Equivalence ratio, @ (d) Variatfon of air specific impulse with cam.
Wtion pressure and.equivalence ratlo. Jnlet- air temperature, 100” F.
Figure 7. - Centinued. Effect of rem-set ccmibustorInlet conditions on theoretical com- bustion perfornumce of liquid hydrogen.
.
.
.
NACA RME53G14 , .
.
.
I@ivelence- .
-/ ratio, + - / ~ 1.0 ~ – - = .- v b - -- .9 172 ~ .
.1 ——— —— 2 .4 .6 .8 1 2 4 6 8 10 Ccaibuet Ion pressure, e+tm (e) ?%xiatlon of air mpeciflc impulse with conibuetion ~easure at selected — equivalenceratios. Inlet-air t~eraturej “100°F.
. . ..- Figure 7. - Concluded..Effect of ram-Jet ccm.ihuetor inlet condition on theo- retical conibustion performance of liquid hydrogen.
.
.
8X NACA RM E53G14 .
-1 D n u Equivalence ratio, Q (a) Variation of cotiuetion temperature with equivalence ratio and inlet-air temperature. Conibuetlon presmre, 2 atmo- spheres.
l Figure 8. - Effect of ram-jet codbuetor Imlet conditione on theoretical conibuetion performance of cryetall.ine alumlnum.
-.
NACA RM E53G14 / A Inlet-air / temperature, OF. , A 180 ~ ‘loo k v’ .
/ .— .2 .4 .6 .
1.o”-- .
Equivalence ratio, Q (b) Variation of air specific impulse with inlet-air temperature and equivalence ratio.. Cmibustion pres- sure, 2 atnmspheres.
Figure 8.
- Continued. Effect of ram-Jet combustor Inlet conditions on theoretical ccmibustion performance of crys- tlimne aluminum.
.
NACA FM E53G14 1 .40xlo-3 Fuel-air ratio 0.2607 .
stokhion&ric .20 I // ..00 I I I I I I I 1 I 11 1 I .80 Iniet-dr tenmereture. .14
I -am “/v, I I I
I I I I t ~-’ -.-/’/; I I
I I I v I I I I
.60 / -.08 \ .40 / \ # .20 ~ -.02 , w specific impulse, Se, lb-see/lb air .
(c) Variation of reciprocal fuel-weight specific lqulse with air specific impulse end inlet-air taqperature. Combut3tion pressure, 2 atnuspheres.
Figure 8. - concluded. EXfect of ram-~et combustor inlet conditions on theo- retical combustion performance e of crystalline aluminum.
MAcA-Lmglq - o-14-sa -am