Document
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[11] Patent Number: 5,184,460
United States Patent [191
[45] Date of Patent: Feb. 9, 1993
Franciscus et al.
References Cited [54] MULTI-HEAT ADDITION TURBINE t561 ENGINE U S . PATENT DOCUMENTS 2,407.166 9/1946 Kreitner et al. ................... 60/39.17 [75] Inventors: Leo C. Franciscus, Lakewood: 2,501.181 4/1950 Constant ............................ 60/226.1 Theodore A. Brabbs, Cleveland, both Seville ................................ 60/39.17 2,584.232 2/1952 of Ohio 2,654,993 10/1953 Owner ................................ 60/39.16 3,867,813 2/1975 Leibach ................................. 60/225 4,206,593 6/1980 Su et al. ............................. 60/39.04 [73] Assignee: The United States of America as represented by the Administrator, Primory Exominer-Louis J . Casaregola National Aeronautics and Space Attorney, Agent, or Firm-Gene E. Shook; Guy Miller; Administration, Washington, D.C. James A. Mackin ABSTRACT NO.: 647,902 [21] Appl.
A multi-heat addition turbine engine (MHATE) incor- porates a plurality of heat addition devices to transfer [22] Filed: Jan. 30,1991 energy to air and a plurality of turbines to extract en- ergy from the air while converting it to work. The MHATE provides dry power and lower fuel consump-
[51] Int. C1.5 ........................... F02K 3/04; FO2K 3/08
tion or lower combustor exit temperatures.
[52] U.S. C1. ................................... 60/226.1; 60/39.17 [58] Field of Search ................. 60/39.04, 39.17, 226.1, 2 Claims, 4 Drawing Sheets 60/39.161, 262, 263
Sheet 1 of 4 5,184,460
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U.S. Patent
Sheet 2 of 4 5,184,460
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U.S. Patent
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U.S. Patent
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FIG. 4
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DISCLOSURE OF T H E INVENTION MULTI-HEAT ADDITION TURBINE ENGINE A gas turbine engine constructed in accordance with ORIGIN OF T H E INVENTION the present invention utilizes heat addition devices be- The invention described herein was made by an em- 5 tween multiple turbines. The heat addition devices transfer energy to air. The turbines extract energy from ployee of the United States Government together with air and convert it to work.
a contractor employee performing work under a NASA This multi-heat addition turbine engine (MHATE) contract and is subject to the provisions of Section 305 provides dry power and lower consumption Or of the National Aeronautics & Space Act (1958), Public 10 lower combustor exit temperatures. The preferred em- Law 85-568 (72 Statute 435; 42 USC 2457).
bodiment comprises a two spool turbofan with six com- TECHNICAL FIELD bustors and six turbines.
This invention is directed to a multi-heat addition BRIEF DESCRIPTION OF THE DRAWINGS turbine engine (MHATE). The invention is particularly 15 The objects, advantages, and novel features of the concerned with a gas turbine engine which incorporates invention Will be more fUlly apparent from the follow- heat addition devices between multiple turbines. The ing detailed description when read in connection with invention further relates to heat addition devices which the accompanying drawings wherein: transfer energy to air, as well as turbines which extract FIG. 1 is a schematic view, in section, of a multi-heat energy from air and convert it to work.
It is desirable to obtain as much dry power from a 2o addition turbine engine constructed in accordance with the present invention; turbine engine as possible. Another goal in the turbine FIG. 2 is a graph showing specific fuel consumption engine art is to lower fuel consumption at the same or plotted against thrust to show comparisons of perfor- lower combustor exit temperatures than utilized in prior mance of multi-heat addition turbine engines (MHATE) art turbine engines.
It is, therefore, an object of the present invention to 2 5 each having a maximum combustion exit temperature of 3260" R. compared with a conventional single combus- provide an improved gas turbine engine whose fuel tor engine having a maximum combustor exit tempera- consumption is lower than conventional turbine en- gines. ture of 3260" R.; FIG. 3 is a graph similar to FIG. 2 with the maximum A further object of the invention is to provide an 3o combustor exit temperature of the multi-heat addition improved gas turbine engine which has the same thrust turbine engines being 2800" R.; and as conventional turbine engines at lower combustor exit FIG. 4 is a graph similar to FIGS. 2 and 3 showing temperatures as well as higher thrust for the same com- bustor exit temperatures as conventional gas turbine the parameters of a four combustor multiple heat addi- engines. 35 tion turbojet having a maximum combustor exit temper- A still further object of the invention is to provide a ature of 2800" R. compared to a conventional single gas turbine engine having longer engine life, lower combustor turbo-jet with a maximum combustor exit temperature of 3260" R.
turbine cooling air requirements, and a potential for lower NO, levels.
BEST M O D E FOR CARRYING O U T T H E B A C K G R O U N D A R T INVENTION U.S. Pat. No. 2,654,993 to Owner is concerned with Referring now to FIG. 1 there is shown a gas turbine gas turbine engines, each comprising a main turbine engine 10 having multiple heat addition devices con- having a pair of rotating rotors through which gas is structed in accordance with the present invention. The passed in succession and an auxiliary turbine to drive 45 engine 10 has a compressor 12 that is powered by a pair the engine which is driven by gasses drawn off from the of turbines 14 and 16. The compressor 12 as well as the rotors of the main turbine. Each engine comprises an turbines 14 and 16 are mounted on a shaft 18.
axial-flow compressor, combustion equipment, and an A fan 20 is mounted adjacent to the compressor 12.
axial flow turbine having a pair of independent rotors The fan 20 is powered by a pair of turbines 22 and 24.
through which the combustor gas is passed in succes- 50 The fan 20 as well as the turbines 22 and 24 are mounted sion. More particularly, gas is bled from between the on a shaft 26.
high and lower pressure turbines, respectively. This In operation engine air indicated by the arrow E goes bled gas powers an auxiliary turbine which may be used through and is compressed in the fan 20. Because the to power an auxiliary engine and/or aircraft accesso- engine 10 is a turbofan, the fan discharge air is split into ries. 55 two streams. The first of these streams indicated by the U.S. Pat. No. 3,867,813 to Leibach is directed to a arrow D is discharged through a bypass nozzle 28. The turbine engine having an additional fan, burner and other stream indicated by the arrow C is compressed turbine to increase power during takeoff and landing. further in the compressor 12 and heated in a combustor These added components are not intended for operation 30.
at other flight conditions. The air passes through the turbine 14 where energy is 60 U.S. Pat. No. 4,206,593 to Su et a1 describes a gas extracted from this air for turbine power causing a de- turbine comprising an air compressor, one or more crease in the air temperature and pressure. The air is combustion chambers, and one o r more expansion tur- heated again in a second combustor 32. This heated air bines. The air compressor, the combustion chambers then passes through the turbine 16 where energy is and the turbines can be placed on one shaft o r on sepa- 65 extracted for turbine power causing still another de- rate shafts so long as the gasses flow in a direction from crease in the air temperature and pressure.
the compressors to the combustion chambers and then The air then is heated in a third combustor 34. This to the turbine. heated air then passes through the turbine 22 where
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energy is extracted for turbine power causing a de- combustor exit temperature (CET,,) of 2800" R. is illus- crease in the air temperature and pressure. trated by the line 64.
The air is again heated in a fourth combustor 36. This The MHATE achieves 20% higher maximum dry heated air then passes through the turbine 24 n.here thrust than the conventional higher temperature turbo- energy is extracted for turbine power, thereby causing a 5 jet. With after burning. the conventional turbojet can decrease in the air temperature and pressure. achieve the same thrust as the MHATE turbojet. At An important novel feature of the MHATE is the lower thrust of 15,000 l b j the SFC's of the M H A T E are placement of the heat addition devices which are the 4% better than the conventional turbojet.
combustors (30,32,34 and 36) between the turbines FIGS. 2, 3 and 4 illustrate a number of advantages of (14,16,22 and 24). The heat addition devices can be any 10 the M H A T E over a conventional single combustor device to transfer energy to the air. The turbines can be engine. These graphs show that the M H A T E exhibits any device capable of extracting energy from the air lower fuel consumption, the same thrust at lower com- and converting it to useful work. The arrangement of bustor exit temperatures, and higher thrust for the same the heat addition devices and turbines is not restricted combustor exit temperature. This results in longer en- to one combustor followed by one turbine, but may be 15 gine life, lower turbine cooling air requirements and a in any combination. NOx levels.
potential for lower Comparisons of the performance of three MHATE While the preferred embodiment of the invention has turbofans with a single combustor turbofan are shown been shown and described it will be appreciated that in FIG. 2. These curves are for a flight mach number of various modifications may be made to the engine with- 2.4 at an altitude of 55,000 feet. The 600 Ib,/sec. turbo- 20 out departing from the spirit of the invention or the fan engines each have a bypass ratio of 1.0. The maxi- scope of the subjoined claims.
mum combustor exit temperature (CET,) is 3260"R. We claim: The performance of a conventional single combustor 1. A multi-heat addition turbine engine (MHATE) engine is illustrated by a curved line 40 having a straight having reduced turbine air requirements and lower after burning portion. The performance of a multi-heat 25 NOx levels comprising
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addition turbine engine ha;ing two combustors is illus- a fan for compressing engine air, trated by the line 42. The line 44 illustrates the perfor- a first shaft for mounting said fan for rotation, mance of an M H A T E having four combustors, while a a compressor for receiving a portion of the com- six combustor M H A T E is shown in line 46. pressed air from said fan and further compressing FIG. 2 shows that at high thrust of 18,000 Ibj the 30 the same.
specific fuel consumption (SFC) of the M H A T E is a second shaft for mounting said compressor for rota- about 13% lower than the single combustor turbofan tion, at least one first combustor for transferring energy to engine. At 10,000 l b j thrust the specific fuel consump- tion of the four types of engines is about the same. said compressed air from said compressor by heat- Referring now to FIG. 3, the performance of a con- 35 ing the same thereby raising the temperature of said ventional single combustor engine with a maximum compressed air, combustor exit temperature of 3260" R. is shown by the a first turbine adjacent to said first combustor and in line 50 having a curved portion at the lower thrust and constant communication therewith for converting a substantially straight line after burning portion at the energy from said heated compressed air to work in higher thrust. The performance of a MHATE having 40 turning said second shaft thereby driving said com- four combustors with an exit temperature of 2800" R. is pressor whereby the temperature of said com- illustrated by the line 54, while a M H A T E having six pressed air is decreased, combustors with an exit temperature of 2800" R. is at least one second combustor adjacent to said first shown by the line 56. turbine and in constant communication therewith The single combustor engine performance illustrated 45 for transferring energy to said energy extracted air by the line 50 is substantially the same as in FIG. 2 with from said first turbine for transferring energy to a maximum combustor exit temperature of 3260" R. said energy extracted air by heating the same Even though the MHATE combustor exit temperatures thereby raising the temperature of said energy ex- are about 460" R. lower than the single combustor en- tracted air, and gine, the maximum dry thrust of the M H A T E engines is 50 a second turbine adjacent to said second combustor higher than that of the conventional single combustor and in constant communication therewith for con- engine and the specific fuel consumptions (SFC), are verting energy from said heated air from said sec- somewhat lower.
ond combustor to work in turning said first shaft Referring now to FIG. 4, the performance of a con- thereby driving said fan whereby the temperature ventional single combustor dry turbojet having a maxi- 5 5 of said heated air is decreased thereby lowering the mum combustion exit temperature (CET,) of 3260" R. NOx levels of the air discharged from said turbine.
is shown by the curved line 62 having a substantiallv 2. A M H A T E as claimed in claim 1 wherein the first straight aftkr burning portion. The performance of shaft is coaxial with the second shaft.
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four combustor MHATE turbojet having a maximum