Document
NASA/TM—2003-212395 AIAA–2003–0903
Mixed-Phase Icing Simulation and Testing
at the Cox Icing Wind Tunnel
Kamel Al-Khalil and Eddie Irani Cox & Company, Inc., New York, New York Dean Miller Glenn Research Center, Cleveland, Ohio
September 2003
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AIAA–2003–0903
NASA/TM—2003-212395
Mixed-Phase Icing Simulation and Testing
at the Cox Icing Wind Tunnel
Kamel Al-Khalil and Eddie Irani Cox & Company, Inc., New York, New York Dean Miller Glenn Research Center, Cleveland, Ohio Prepared for the 41st Aerospace Sciences Meeting and Exhibit sponsored by the American Institute of Aeronautics and Astronautics Reno, Nevada, January 6–9, 2003 National Aeronautics and Space Administration Glenn Research Center
September 2003
Acknowledgments This program was sponsored by the FAA through a contract to Wichita State University. The support of these two organizations is well appreciated. Participation of the NASA Glenn Research Center in this program provided valuable imaging techniques and recorded visualization.
The Propulsion and Power Program at NASA Glenn Research Center sponsored this work.
Available from NASA Center for Aerospace Information National Technical Information Service 7121 Standard Drive 5285 Port Royal Road Hanover, MD 21076 Springfield, VA 22100 Available electronically at http://gltrs.grc.nasa.gov MIXED PHASE ICING SIMULATION AND TESTING AT THE COX ICING WIND TUNNEL † Kamel Al-Khalil* and Eddie Irani Cox & Company, Inc.
New York, New York 10014 ‡ Dean Miller National Aeronautics and Space Administration Glenn Research Center Cleveland, Ohio 44135 ABSTRACT A new capability was developed for indoor simulation of snow and mixed-phase icing conditions. This capability is useful for year-round testing in the Cox closed-loop Icing Wind Tunnel. Certification of aircraft for flight into these types of icing conditions is only required by the JAA in Europe. In an effort to harmonize certification requirements, the FAA in the US sponsored a preliminary program to study the effects of mixed-phase and fully glaciated icing conditions on the performance requirements of thermal ice protection systems. This paper describes the test program and the associated results.
1.0 INTRODUCTION Since the ATR-72 accident, the FAA and the JAA have been working on joint programs in order There are requirements and advisory materials harmonize the certification requirements. The FAA under Joint Airworthiness Requirements (JAR) in issued a document detailing its in-flight aircraft icing Europe that must be satisfied prior to flight into plan, the purpose of which is to increase flight safety mixed icing and snow conditions [1]. To achieve [11]. Among the list of tasks is Task 13. Here, the certification for flight into these conditions, aircraft objective is to characterize SLD aloft and assess must demonstrate compliance with those mixed phase conditions in the atmospheric flight requirements. In the USA, the Federal Aviation environment. Specifically, Task 13C states that Administration (FAA) has issued no such “The FAA will conduct a study to determine the requirements to date other than those restricted to magnitude of the safety threat that is posed by falling and blowing snow with no mention of mixed phase conditions.” airspeed [2].
Consequently, the FAA sponsored a specialists' In recent years, several flight programs were workshop on mixed-phase and glaciated icing conducted in order to re-characterize the conditions in Dec 1998. Several presentations were atmosphere at different locations around the globe. given on the topic as indicated by References [12] Most of these programs were geared towards and [13]. The experience of authors and experts in Supercooled Large Droplets (SLD). Among these the field is that both snow and mixed icing programs are the NASA Glenn Research Center conditions could constitute flight hazards beyond icing research flights throughout the Great Lakes those recognized formally. Insidious accumulations region, the Canadian Freezing Drizzle Experiment of ice and packed snow in engine inlets and at (CFDE) and the Alliance Icing Research Study various locations on the airplane can occur. As (AIRS). References [3] through [10] include already mentioned, the JAA recognizes the discussions on those programs. SLD icing hazardous nature of mixed phase and snow conditions are believed to have been a factor in the conditions and requires testing for engines and air 1994 fatal crash of an ATR-72 commuter aircraft. data probes and instrumentation.
There is evidence from those flight research The effect of these conditions on heated or programs that mixed phase icing conditions can be unheated lifting surfaces has not been encountered relatively frequently. In mixed icing systematically evaluated and documented. In order conditions, ice crystals and supercooled water to address this issue, the FAA sponsored a program droplets coexists. to investigate the impact of mixed phase and snow conditions on thermal ice protection systems. An exploratory test was conducted in the Cox & Company Icing Wind Tunnel (IWT) in July 2002.
This was a collaborative effort between the FAA, * Manager, LIRL Icing Wind Tunnel, Senior Member AIAA †Aerospace Research Engineer, Member AIAA Wichita State University, Cox & Company, and ‡Icing Research Engineer, Member AIAA NASA Glenn Research Center.
NASA/TM—2003-212395 1 many of the tests were conducted at the same Total 2.0 OBJECTIVES AND APPROACH Water Content (TWC). The ratio of ice water content to supercooled liquid water content was Cox developed a new capability in its IWT (Figure 1) varied between 0%, 50%, and 100%. The IPS to simulate mixed phase and glaciated icing operation in the two different modes was conducted conditions. The development program was carried at the following temperatures: out through NASA Glenn SBIR Phase-I and Phase-II awards. This capability was necessary to Evaporative Anti-icing: surface near 150 °F conduct the current program.
Running-Wet power: surface near 50 °F The primary objective of this experimental program was to study the effect of mixed phase and The surface temperature in the evaporative mode glaciated icing conditions on the performance of was higher than the normally used, 120°F. This thermal ice protection systems. The secondary was a result of the low air speed which gives a low objective was to study the physics of ice particle evaporation rate, and also because water near the behavior on airfoil leading edge surfaces (impact, stagnation has a greater tendency to bead up at low bouncing, sticking, melting, etc.). A team of speed and then run back, producing a frozen ridge engineers from NASA Glenn Research Center beyond the heated zone.
carried out the visualization effort using state-of-the- art imaging tools and techniques. In both heated modes, the power distribution and total power was determined through a closed-loop A heated and instrumented airfoil model was used control system. In the unheated cases, the surface in the studies. The heated section consisted of physics and erosion effects of the incoming particles multiple zones that were individually controlled as on the ice structure were studied and documented.
described later. The model was previously developed for the NASA Code Validation Test 3.0 ICING CLOUD SIMULATION Program that was conducted in the NASA IRT as described in References [14], [15] and [16]. The The simulation of the different icing clouds was original airfoil model was trimmed from 6 ft to 4 ft made possible by using a combination of ice and/or span in order to fit in Test Section-2 of the Cox IWT. supercooled water. The latter was produced using This test section was chosen to allow atomized the common spray bar method where filtered and particles from the Snow Gun, described later, to de-ionized water was atomized using compressed nearly fully freeze prior to impact on the model heated air. The ice particles were produced using leading edge. two different methods: Testing was conducted with the model heaters OFF Snow gun: and ON. The objective of keeping the heaters OFF was to explore and document the icing physics on Water was atomized through a nozzle using the surface, including ice particles impacting the cold compressed air as shown in Figure 2. The surface, bouncing off, partially sticking, melting, etc. cooling of the atomized water droplets produced In the heater ON case the objective was to near spherical ice particles.
document the changes in the icing physics and to determine the power required to maintain the Ice Shaver: surface at a certain preset temperature.
Water was frozen in large ice blocks.
There are two anti-icing modes of operation of a Subsequently, these blocks were fed at a thermal Ice Protection System (IPS): evaporative determined rate through a mechanical shaver and running-wet. In the evaporative mode, the that consisted of multiple rotating blades. The surface is heated sufficiently to evaporate the shaved ice was then introduced into the impinging ice/water particles and prevent runback freestream via a blower. The ice particles beyond the heated zone. This requires a surface produced using this technique are usually temperature near to or in excess of 120°F. In the irregular in shape and larger than those running-wet mode, the surface is heated to prevent produced using the snow gun. Also, the the impinging ice/water particles from freezing within particles are fully frozen as they are produced.
the heated zone. This requires a surface Those generated using the snow gun required temperature above 32°F, in practice between 40 some residency time in the freestream in order and 50°F. to freeze prior to impacting the test model.
In order to quantify the effects of ice/water content Since differences in particle size and shape can in the cloud on thermal IPS power requirements, affect impact characteristics, it was desired to NASA/TM—2003-212395 2 document particle features. An OAP 2D-Grey laser conducted in Test Section-2 where the speed is probe was used to characterize details of ice limited to 120 mph. This section was chosen to particles from the snow gun and the ice shaver. insure that all ice particles produced using the snow The instrument was installed at the same location gun were fully frozen. The goal was to obtain as the test model prior to the test program. Ice additional information from effect of ice particle size particle images from the snow gun and the ice and shape using the two different simulation shaver are shown in Figure 3. Sample results of methods.
particle size distribution are shown in Figures 4 and 5 for the snow gun and ice shaver, respectively. The airfoil was mounted horizontally in Test Corresponding Mean Volume Diameters (MVD’s) Section-2 as shown in Figure 6. All tests were were approximately 150 and 185 microns, conducted at a single, zero degree angle of attack respectively. In general, ice shaver particle MVD due to the extent of the tasks to be accomplished was near or above 200 microns. within the limited time period. A detailed description of the 3 ft chord by 4 ft span NASA0012 heated The Ice Water Content (IWC) using the snow or the airfoil model is provided in Reference [14]. It ice shaver was calibrated prior to testing. This was consisted of 14 individually powered and controlled accomplished using the Nevzorov TWC instrument, heater zones. The layout and numbering of the which consists of two sensors: (1) a LWC sensor, heaters is shown in Figure 6. Seven heaters were and (2) a TWC sensor. The IWC is computed from duplicated spanwise for redundancy. Additionally, the difference between the TWC and the LWC. due to the airfoil symmetry and zero degree flow Generally, the IWC is slightly under-estimated since angle of attack, top and bottom redundancy the LWC sensor has some thermal response from resulted.
ice particles, which are assumed to bounce off that sensor. Ice particles are assumed to be collected, The model was fitted with several sensors. Only along with water particles, on the TWC sensor. This those that measured the surface temperature near does not account for few ice particles bouncing off the mid-span were used to acquire data and control the TWC sensor, especially in the fully glaciated the heater power. These were located at +/-4.5 conditions. Correspondingly, the IWC might be inches on either side of the mid-span, centered slightly underestimated. The overall accuracy of the within each heater width.
Nevzorov probe is acceptable and meets the purpose of this test program. The video imaging setup is shown in Figure 7.
Three cameras were used to image the leading The cloud simulations were as follows: edge of the test article: Supercooled: 1) A High Definition (HD) video Camera and Recorder were used to capture close-up Tunnel Spray Bars : NASA type nozzles details of ice particle impact in high (MOD-1) resolution 2) A high speed close-up camera to allow slow Glaciated: motion analysis of impact (Phantom V High- frame rate) Snow Gun : Air assisted atomization and 3) A mini digital video camera with a wide field freeze-out of water particles of view to provide context for the other two cameras Ice Shaver : Mechanically shaved frozen ice blocks and dispersed in the freestream 5.0 DATA ACQUISITION AND CONTROL Mixed: The Cox Thermal Test Management System Supercooled + Ice Shaver (TTMS) was used to power the 14 heated zones Supercooled + Snow Gun and record the data. The TTMS is a computer based test management and data acquisition 4.0 TUNNEL TEST SETUP system. Power was regulated to each particular zone to maintain the specified constant surface The IWT shown in Figure 1 can simulate airspeeds temperature for each of the two anti-icing modes of in excess of 200 mph at temperatures below –22 °F operation (evaporative and running-wet).
(–30 °C) in its upstream Test Section-1. This section measures 28 inches wide by 46 inches high. In most cases, the TTMS modulated the power The tunnel has a diffuser expanding linearly below 100% duty cycle to maintain the surface at between this test section and the larger (48”x48”) 50°F in the running-wet modes. However, the hilite Test Section-2 downstream. All tests were heaters (#4 and #11) were running at full power in NASA/TM—2003-212395 3 evaporative cases as well as in several running-wet stagnation region, this region has low collection cases. The corresponding surface temperature was efficiency and high local tangential speeds that may lower than the preset values, but higher than the cause increased erosion of the accretions. The freezing temperature. Specific details are discussed rime accretions tended to have a smoother in the thermal results section. appearance in the mixed rime conditions due to the “sand-blasting” effects of the particles.
6.0 ICING TUNNEL TESTS In mixed glaze ice conditions erosion effects are Testing was conducted at various environmental clearly more significant. To illustrate these effects conditions. Table 1 lists the icing test conditions to two cases were conducted at 22°F. Figure 9 be explored. Generally, a mid-range ambient illustrates ice tracings from Runs 9 and 10. In temperature (12°F - glaze) and a cold ambient Run 9, only supercooled liquid water at 0.7 g/m condition (0°F - rime) were considered. All tests was used. The clear ice accumulation in the were run at 120 mph and zero degree angle of stagnation region and the beginning formation of attack. Generally, the TWC was near 0.7 g/m . horns away from the stagnation was an indication of Other variations were also explored. The list of glaze ice accretion where the freezing fraction was icing runs and associated icing conditions from less than unity. In Run 10, 0.7 g/m of frozen ice Table 1 are shown in Table 2. This table also particles were added to the cloud, producing a TWC indicates the IPS heater mode of operation in each of 1.4 g/m . Surprisingly, the accreted ice was run. The duration of the icing conditions in all the decreased instead of increased. The ice feathers runs was 10 minutes or until stable results were and “horns” disappeared compared to the previous obtained. case. In addition, a slight reduction in accreted ice around the stagnation area is visible from the 6.1 IMAGING AND VISUAL RESULTS tracings. This could be caused by a combination of erosion and splashing of the existing liquid layer in A detailed analysis of the visualization data has not that area due to the low freezing fraction.
been performed yet. However, a few general Interestingly, the accreted ice changed from clear to observations about the data are possible. opaque white as in the rime cases with a slight bumpy texture. The explanation could be that Bouncing of ice particles was observed in all runs, impacting ice particles leave residuals that get with a heated or unheated surface, and with or trapped by the liquid layer. In addition, the smaller without a supercooled liquid water spray. With the ice particles may actually stick to the surface when current visualization and imaging instruments, it is a liquid layer exists. In rime cases, the supercooled not yet possible to quantify the amount of particles water droplets freeze on impact, leaving a smooth that bounce off the surface. Figure 20, located at hard surface for ice particles to strike and bounce the end of this document, illustrates these effects as off, the same as in the case of the fully glaciated captured during Run 37 (Condition 10). icing conditions.
In the unheated tests in glaciated conditions, only a When the surface is heated, significant liquid water layer of frost was visible on the surface with no is observed on the surface around the stagnation further accumulation as time progressed. This layer region in the evaporative case and over the entire is thought to be the residual of ice particles heated region and beyond in the running-wet case.
impacting the surface. This was observed for both This was observed whether the icing conditions the ice shaver and the snow gun. In mixed phase were due to all liquid supercooled water, mixed- unheated conditions, the phenomenon of erosion phased, or fully glaciated conditions. This indicates was observed on the accreted ice. The effects were that ice will stick, at least partially, to heated temperature dependent. surfaces. The videos still showed particles bouncing, but the magnitude could not be quantified Figure 8 illustrates the effect of erosion on accreted with current imaging tools. Splashing is another ice in mixed rime icing conditions. These phenomenon observed that could not be readily correspond to Runs 19 and 20. Based on the quantified.
known conditions and collection efficiency of the supercooled water droplets, it is apparent that the For each test run, a movie sequence has been ice shapes were a result of the supercooled water created from the available video camera footage droplets in the mixed cloud. The existence of the and any still photos of the resulting ice accretion.
ice particles in the mix did not seem to significantly affect the amount of accreted ice. The only 6.2 THERMAL TEST RESULTS noticeable effect of the ice particles was the erosion of the feather-like ice growths close to the The validity of the thermal data relies on the impingements limits. Compared to near the following: NASA/TM—2003-212395 4 value. Figure 12 illustrates the normalized total powers at 0°F ambient temperature.
• Accuracy of the tunnel simulation capability of the various conditions In the following discussions and figures, “Spray • Model design and instrumentation Bars” indicates only supercooled liquid water, • TTMS data acquisition and control “MixGun” and “MixShaver” indicates a mixed-phase condition with 50% water content, and “Shaver” or The repeatability of the tunnel capabilities in “Gun” indicates fully glaciated icing conditions. The supercooled liquid water conditions has been dry condition data is shown for reference. The established over the last several years. Considering spanwise and chordwise symmetric data have been that the mixed phase simulation is a new addition to averaged so that the results for seven heaters only the tunnel simulation capabilities, its accuracy will are presented.
have to be proven by repeated testing over the next few months or years. However, the following results The general trend observed suggests that the indicate that the data is meaningful and predictable maximum power in a decreasing order for the in relation to the corresponding conditions.
evaporative cases is as follows: A dry heated test is a very good measure of 1) All supercooled water droplets repeatability of other tunnel conditions (airspeed 2) Mixed-phase icing conditions and temperature), the model instrumentation, and 3) Fully glaciated icing conditions the TTMS data acquisition and control. In most runs, the model was stabilized to evaporative Looking at the actual distribution of these powers surface temperature conditions. The individual sheds more light on the effects of ice particles in the heater powers were measured by the TTMS. The cloud. Figure 13 illustrates the distributions resulting data was used to compute the external corresponding to evaporative powers at 0°F. The heat transfer coefficient for each heater. Results at case labeled “Gun low LWC” corresponds to ice two ambient conditions are shown in Figures 10 and crystals only at 0.35 g/m . The results showed a 11. It is clear that the results are very consistent reduction of power required for that case. There are between all the different runs. The slight non- two interesting phenomena to observe: symmetry in the results is associated with the hilite heaters (#4 and #11) being offset chordwise by as 1) Power on the edge heaters, specifically #2 much as 0.1 to 0.18 inch from the hilite. At the aft and #6, are reduced in the case of mixed or most heaters (Numbers 1, 7, 8, and 14), an increase glaciated conditions. This could be another in the heat transfer coefficient was noticed. This indication for erosion.
was due to transition from laminar to turbulent flow.
2) The power required on the hilite, heater #4, Due to the large volume of data to be presented, is near 31 W/in . This corresponds to the cases for the two different ambient temperatures will maximum heater design power. In those be discussed separately. However, It will be shown cases, the hilite heater ran below the that the colder conditions were more severe, specified surface temperature of 150°F.
requiring more power, than the warmer ones for the same cloud conditions.
Similarly, the results corresponding to evaporative conditions at 12°F ambient temperature are shown The total power was computed for all heaters for the in Figures 14 and 15. The trend observed here is following conditions: identical to the colder case. But the respective normalized powers are slightly lower due to the 1) Evaporative at 0°F ambient decrease in the convective and evaporative losses.
2) Evaporative at 12°F ambient However, the erosion effects are more visible in 3) Running-wet at 0°F ambient Figure 15 in the heated regions just downstream of 4) Running-wet at 12°F ambient the hilite than in the corresponding Figure 13 for the 0°F case.
6.2.1 Evaporative Anti-icing 6.2.2 Running-wet Anti-icing All the results are presented for a TWC of 0.7 g/m unless otherwise specified. The highest power Now consider the running-wet anti-icing cases.
required of all of the runs was determined to Figure 16 illustrates the normalized total powers at correspond to the case of supercooled liquid water 0°F ambient temperature. Clearly, the total required only, at 0°F ambient temperatures, and in the fully power is much less than in the evaporative cases.
evaporative case. Consequently, all the powers The trend shown here indicates that the power from the different runs were normalized to that required in decreasing order corresponds to the NASA/TM—2003-212395 5 mixed phases, followed by the fully glaciated and atmosphere. In fact, the total power requirements supercooled droplets clouds. may be reduced in mixed-phase conditions as a result of the observed erosion effects.
Detailed inspection of the actual power distributions shown in Figure 17 indicates that for most running- Running-wet thermal systems on lifting surfaces can wet cases the power on the hilite is also the be overwhelmed at the stagnation region by high ice maximum available, as in the evaporative cases. contents when insufficiently heated, but the overall Notably, the heaters just downstream of the hilite power requirements are still insignificant compared required very little heat in mixed and glaciated to evaporative cases. Consequently, if a system is conditions. There are two possible reasons for that: designed to operate at or near evaporative power levels, it should function satisfactorily in mixed- 1) The ice accumulation on the hilite required phase conditions. In running-wet operations, the high power as a result of the additional heat power requirements were generally highest in mixed of fusion required to melt the ice crystals. icing conditions compared to fully glaciated or Some of the heat generated on the hilite supercooled liquid only cloud conditions.
conducts in the chordwise direction to adjacent heaters. The test methodologies and imaging tools developed in this program can be transferred to an 2) The erosion effects observed on the aircraft test bed for flight studies in natural icing unheated model in glaze ice conditions conditions. However, extensive data should be could have played a role here. The liquid collected to be conclusive. An actual flight test runback water downstream of the hilite may program might prove very difficult due to the high have been removed from the surface by the fluctuations in ambient conditions.
solid particles, which strike those regions and bounce off the surface producing a Other applications for mixed phase testing in the “sand blasting” effect as presented in the tunnel include the investigation of heated ice tracing earlier. instrumentation and air data probes. Also, if the ice shaver is used, higher speed effects and better Finally, the results corresponding to running-wet close-up imaging can be conducted in TS-1 of the cases at 12°F ambient temperature are shown in Cox IWT since current data is limited to a speed of Figures 18 and 19. The trend observed here is 120 mph.
similar to that of the 0°F case as far as the power distributions and erosion effects. Generally, the The studies were conducted with currently available powers in this warm case are small compared to the simulation methods and visualization techniques.
evaporative cases.
Although the ice particles simulated here may represent only a small percentage of the types that 7.0 CONCLUDING REMARKS may exist in nature and direct correlations to nature may not be possible, the trends observed are A new capability to simulate glaciated and mixed- expected to be valid. This is especially true in the phase icing conditions was developed and case of heated surfaces.
demonstrated in the Cox IWT. An experimental program, sponsored by the FAA, was conducted to 8.0 REFERENCES quantify the effects of mixed-phase and glaciated icing conditions on the power requirements of 1. JAR Requirements - Mixed Phase Icing: JAR thermal ice protection systems. The investigation 25.1419 and ACJ 25.1419.
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NASA/TM—2003-212395 7 Figure 1: Layout of the IWT at the Cox LeClerc Icing Research Laboratory Figure 2: Snow gun in the Cox IWT
Snowgun Shaved Ice
1 mm
Figure 3: Ice Particle imaging using the OAP-2Dgrey probe NASA/TM—2003-212395 8 Example Drop Size Distribution - Snow Gun Example Particle Size Distribution - Ice Shaver 9 8 LWC (%) LWC (%) 15 45 75 105 135 165 195 225 255 285 315 345 375 405 435 16.6 45.4 105 135 165 195 225 255 285 315 345 375 405 435 Particle Size (microns) Particle Size (microns) Figure 4: Sample snow gun particle distribution Figure 5: Sample ice shaver particle distribution Figure 6: NACA0012 Model (36” chord) Installed in TS-2 Figure 7: Video Imaging Setup NASA/TM—2003-212395 9 Table 1: Icing Test Conditions Icing True Total Spraybar * Snow Gun Ice Shaver Test AirSpeed Temp. LWC IWC IWC TWC 3 3 3 3 Condition (mph) (°F) (g/m ) (g/m ) (g/m ) (g/m ) WARM 1 120 12 0.70 0.70 2 120 12 0.35 0.35 0.70 3 120 12 0.30 0.70 1.00 4 120 12 0.70 0.30 1.00 5 120 12 0.35 0.35 0.70 6 120 12 0.70 0.70 7 120 12 0.70 0.70 COLD 8 120 0 0.70 0.70 9 120 0 0.35 0.35 0.70 10 120 0 0.35 0.35 0.70 11 120 0 0.70 0.70 12 120 0 0.70 0.70 13 120 0 0.30 0.30 WARMEST (TRACINGS ONLY) 14 120 22 0.70 0.70 15 120 22 0.70 0.70 1.40 * Supercooled water droplets, MVD = 20 microns Table 2: Matrix of Icing Test Runs Tunnel Icing IPS Tunnel Icing IPS Run Test Thermal Run Test Thermal No. Condition Condition No. Condition Condition 7/16/2002 7/18/2002 (continued) 1 6 Off 24 9 Off 2 6 Off 25 8 Evap 3 5 Off 26 8 Run-wet 4 5 Off 27 11 Evap 5 1 Off 28 11 Run-wet 6 11 Off 7/19/2002 7 10 Off 29 2 Evap 8 8 Off 30 2 Run-wet 7/17/2002 31 7 Evap 9 14 Off 32 7 Run-wet 10 15 Off 33 9 Evap 11 1 Evap 34 9 Run-wet 12 1 Run-wet 35 12 Evap 13 5 Evap 36 12 Run-wet 14 5 Run-wet 37 10 Evap 15 6 Evap 38 10 Run-wet 16 6 Run-wet 39 10 Off 17 6 Run-wet 40 13 Evap 7/18/2002 7/23/2002 18 2 Off 41 12 Evap 19 3 Off 42 12 Run-wet 20 4 Off 43 9 Off 21 7 Off 46 12 Evap 22 13 Off 44 11 Evap 23 12 Off 45 11 Run-wet NASA/TM—2003-212395 1 0 Run 20 Run 20 Run 19 Run 19 Figure 8: Erosion effects on ice accretions in rime conditions Run 9 Run 9 Run 10 Run 10 Figure 9: Erosion effects on ice accretions in glaze conditions NASA/TM—2003-212395 1 1 Heat Transfer Coefficient Heat Transfer Coefficient Dry Data at 12°F Ambient and Evaporative Powers Dry Data at 0°F Ambient and Evaporative Powers Run 11 Run 25 Run 13 Run 33 Run 15 .°F)] Run 35 Run 29 Run 37 Run 31 Average Average HTC [Btu/(hr.ft HTC [Btu/(hr.ft2.°F)] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Heater Number Heater Number Figure 10: Tunnel Sample Dry Data at 12 °F Figure 11: Tunnel Sample Dry Data at 0 °F Evaporative Power Distributions (OAT = 0 °F) Normalized Evaporative Anti-Icing Power (OAT = 0°F) 1.0 0.9 0.8 0.7 ) 0.6 0.5 0.4 Bars 0.3 Mix-Gun q" (W/in 0.2 Mix-Shaver Normalized Total Power 0.1 Shave 0.0 Gun Gun low-LWC 0°F 0°F 0°F (LWC-) Dry 0°F MixGun Gun 0°F Gun 0°F 1 2 3 4 5 6 7 MixShaver Shaver 0°F Spray Bars Heater No.
Figure 12: Summary of Normalized Evaporative Total Power at 0°F Figure 13: Evaporative Power Distributions at 0°F Evaporative Power Distributions Normalized Evaporative Anti-Icing Power (OAT = 12 °F) (OAT = 12°F) 1.0 0.9 0.8 0.7 0.6 ) 0.5 0.4 0.3 15 Bars q" (W/in 0.2 Normalized Total Power Mix-Gun 0.1 Mix-Shaver 0.0 Gun Shaver 12°F 12°F 12°F Shaver 0 Spray MixGun Dry 12°F Gun 12°F Bars 12°F MixShave 1 2 3 4 5 6 7 Heater No.
Figure 14: Summary of Normalized Evaporative Total Power at 12°F Figure 15: Evaporative Power Distributions at 12°F NASA/TM—2003-212395 1 2 Normalized Running-Wet Anti-Icing Power Running-wet Power Distributions OAT = (0 °F) (OAT = 0°F) 1.0 Mix-Shaver 0.9 Mix-Gun 0.8 Gun1 0.7 Gun2 0.6 ) 2 Shaver1 0.5 Shaver2 0.4 Bars 0.3 0.2 q" (W/in Normalized Total Power 0.1 0.0 0°F 0°F Spray Dry 0°F MixGun Gun 0°F Bars 0°F MixShaver Shaver 0°F 1 2 3 4 5 6 7 Heater ID Figure 16: Summary of Normalized Running-Wet Total power at 0°F Figure 17: Running-Wet Power Distributions at 0°F Running-wet Power Distributions Normalized Running-Wet Anti-Icing Power (OAT = 12 °F) (OAT = 12°F) 1.0 Shaver1 0.9 Shaver2 0.8 Gun 0.7 Mix-Gun ) 0.6 Mix-Shaver 0.5 Bars 0.4 0.3 q" (W/in 0.2 Normalized Total Power 0.1 0.0 12°F 12°F 12°F Shaver Shaver 12°F Spray MixGun Dry 12°F 1 2 3 4 5 6 7 Gun 12°F Bars 12°F MixShaver Heater ID Figure 18: Summary of Normalized Running-Wet Figure 19: Running-Wet Power Distributions at 12°F Total power at 12°F Figure 20: Ice Particle Impact/Bounce captured during Run 37 NASA/TM—2003-212395 1 3 Form Approved REPORT DOCUMENTATION PAGE OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188), Washington, DC 20503.
2. REPORT DATE 3. REPORT TYPE AND DATES COVERED 1. AGENCY USE ONLY ( Leave blank) Technical Memorandum September 2003 4. TITLE AND SUBTITLE 5. FUNDING NUMBERS Mixed-Phase Icing Simulation and Testing at the Cox Icing Wind Tunnel WBS–22–708–20–03 6. AUTHOR(S) Kamel Al-Khalil, Eddie Irani, and Dean Miller 8. PERFORMING ORGANIZATION 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) REPORT NUMBER National Aeronautics and Space Administration John H. Glenn Research Center at Lewis Field E–13978 Cleveland, Ohio 44135 – 3191 10. SPONSORING/MONITORING 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) AGENCY REPORT NUMBER National Aeronautics and Space Administration NASA TM—2003-212395 Washington, DC 20546– 0001 AIAA–2003–0903 11. SUPPLEMENTARY NOTES Prepared for the 41st Aerospace Sciences Meeting and Exhibit sponsored by the American Institute of Aeronautics and Astronautics, Reno, Nevada, January 6–9, 2003. Kamel Al-Khalil and Eddie Irani, Cox & Company, Inc., New York, New York 10014; Dean Miller, NASA Glenn Research Center. Responsible person, Dean Miller, organization code 5840, 216–433–5349.
12b. DISTRIBUTION CODE 12a. DISTRIBUTION/AVAILABILITY STATEMENT Unclassified - Unlimited Subject Categories: 03 and 34 Distribution: Nonstandard Available electronically at http://gltrs.grc.nasa.gov This publication is available from the NASA Center for AeroSpace Information, 301–621–0390.
13. ABSTRACT (Maximum 200 words) A new capability was developed for indoor simulation of snow and mixed-phase icing conditions. This capability is useful for year-round testing in the Cox closed-loop Icing Wind Tunnel. Certification of aircraft for flight into these types of icing conditions is only required by the JAA in Europe. In an effort to harmonize certification requirements, the FAA in the U.S. sponsored a preliminary program to study the effects of mixed-phase and fully glaciated icing conditions on the performance requirements of thermal ice protection systems. This paper describes the test program and the associated results.
14. SUBJECT TERMS 15. NUMBER OF PAGES Supercooled large droplets (SLD) icing conditions; ATR-72 accident; Mixed-phase; 16. PRICE CODE Glaciated icing conditions; Alliance icing research study (AIRS); Canadian freezing drizzle experiment (CFDE) 19. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION 17. SECURITY CLASSIFICATION 20. LIMITATION OF ABSTRACT OF ABSTRACT OF THIS PAGE OF REPORT Unclassified Unclassified Unclassified NSN 7540-01-280-5500 Standard Form 298 (Rev. 2-89) Prescribed by ANSI Std. Z39-18 298-102