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4、side USA)Fax: 724-776-0790Email: CustomerServicesae.orgSAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedbackon this Technical Report, please visithttp:/www.sae.org/technical/standards/AIR4869AAEROSPACEINFORMATION REPORTAIR4869 REV. AIssued 1995-10Revised 2009-05Reaffirmed 2015
5、-09Superseding AIR4869Design Considerations for Enclosed Turbofan/Turbojet Engine Test CellsRATIONALEAIR4869A has been reaffirmed to comply with the SAE five-year review policy.FOREWORD One of the strongest motives for documenting the considerations which are judged important in the design of enclos
6、ed ground-level testing facilities for turbofan and turbojet engines as described in this work was the generally poor understanding of the aerodynamics associated with the test cell environment. In those instances where the understanding was not so poor, there sometimes remained a lack of appreciati
7、on for the fundamental importance of the aerodynamics of the engine testing environment. It is known that such a poor understanding or a lack of appreciation for the importance of the aerodynamics of the testing environment can and does lead to disastrous consequences. Recent research work has led t
8、o a much improved understanding and heightened awareness of the fundamental importance of the aerodynamics of the engine testing environment and has resulted in significantly improved engine test facilities now in use worldwide. This document is intended for individuals associated with the ground-le
9、vel testing of large and small gas turbine engines and particularly those who might be interested in upgrading their existing or acquiring new test cell facilities. Turbofan and turbojet engines operating in a ground-level test cell can encounter a number of problems which are directly attributable
10、to the characteristics of the test cell environment. Some of the more important factors which must be considered in the development of test cell designs leading to desired engine operational stability, aerodynamic performance, and acoustic control are described. Test cell performance goals which typ
11、ically might be used to define “excellent“ cell performance are included. When these cell performance goals are achieved, stable and repeatable engine operation can be assured. Recent research conducted in scale model test studies, reinforced by results from a number of full-scale operational experi
12、ences, has assisted the evolution of engine test cell design and attacked the need for improved engine test facilities. TABLE OF CONTENTS 1. SCOPE 3 1.1 Purpose . 3 2. REFERENCES 3 2.1 Applicable Documents 3 2.2 Symbols and Abbreviations 4 2.2.1 Parameters 4 2.2.2 Abbreviations 5 2.2.3 Subscripts .
13、5 3. TECHNICAL BACKGROUND . 5 4. TEST CELL SYSTEM DESIGN CONSIDERATIONS . 6 4.1 Inlet Plenum 7 4.2 Test Chamber . 7 4.3 Augmentor . 7 4.4 Exhaust Stack . 8 5. FACTORS FOR EVALUATING TEST CELL PERFORMANCE . 8 5.1 Front Cell Velocity Distortion . 8 5.2 Front Cell Airflow . 9 5.3 Bellmouth Total Pressu
14、re Distortion . 9 5.4 Cell Bypass Ratio 10 5.5 Cell Depression . 11 6. GENERAL TEST CELL REQUIREMENTS AND GOALS 11 7. CONCLUSIONS 12 8. NOTES 12 APPENDIX A AIRFLOW EQUATIONS . 13 FIGURE 1 GENERAL DESIGN CONCEPTS FOR AN ENGINE TEST CELL FOR A LARGE, HIGH-BYPASS TURBOFAN ENGINE 6 FIGURE 2 BELLMOUTH-IN
15、GESTED VORTEX FORMATION RESULTS AS A FUNCTION OF CELL BYPASS RATIO AS DETERMINED FROM VIDEO TAPE RECORDS OF FLOW VISUALIZATION (FROM REFERENCE 2.1.2) . 10 SAE INTERNATIONAL AIR4869A 2 OF 141. SCOPE This SAE Aerospace Information Report (AIR) has been written for individuals associated with the groun
16、d-level testing of large and small gas turbine engines and particularly for those who might be interested in upgrading their existing or acquiring new test cell facilities. 1.1 Purpose There are several purposes served by this document: a. To provide guidelines for the design of state-of-the-art gro
17、und-level enclosed test facilities for turbofan and turbojet engine testing applications. b. To address the major test cell/engine aerodynamic and acoustic characteristics which can influence the operation of a gas turbine engine and its performance stability in a test cell. c. To consider acoustic
18、environmental impact and methods to control it. 2. REFERENCES The following publications for a part of this document to the extent specified herein. The latest issue of SAE publications shall apply. The applicable issue of the other publications shall be the issue in effect on the date of the purcha
19、se order. In the event of conflict between the text of this document and references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 2.1 Applicable Documents The foll
20、owing is a list of some applicable references and documents used in the preparation of this document: 2.1.1 Karamanlis, A. I., Sokhey, J. S., Dunn, T. C., and Bellomy, D. C.: “Theoretical and Experimental Investigation of Test Cell Aerodynamics for Turbofan Applications“, AIAA Paper No. 86-1732, Pap
21、er presented to the AIAA/ASME/SAE/ASEE 22nd Joint Propulsion Conference, Huntsville, Alabama, June 16-18, 1986 2.1.2 Freuler, R. J., and Dickman, R. A.: “Current Techniques for Jet Engine Test Cell Modeling“, AIAA Paper No. 82-1272, Paper presented to the AIAA/SAE/ASME 18th Joint Propulsion Conferen
22、ce, Cleveland, Ohio, June 21-23, 1982 2.1.3 Karamanlis, A. I., Freuler, R. J., Lee, J. D., Hoelmer, W., and Bellomy, D. C.: “A Universal Turboshaft Engine Test Cell - Design Considerations and Model Test Results“, AIAA Paper No. 85-0382, Paper presented to the AIAA 23rd Aerospace Sciences Meeting, R
23、eno, Nevada, January 1985 2.1.4 Grunnet, J. L., and Ference, E.: “Model Test and Full-Scale Checkout of Dry-Cooled Jet Runup Sound Suppressors“, AIAA Paper No. 82-1239, AIAA/SAE/ASME 18th Joint Propulsion Conference, Cleveland, Ohio, June 21-23, 1982 2.1.5 “Gas Turbine Engine Test Cell Correlation“,
24、 SAE Aerospace Recommended Practice ARP741, Society of Automotive Engineers, Warrendale, Pennsylvania, Issued March 1976, Reaffirmed October 1982. (Note: This ARP was revised and reissued as ARP741 Revision A in September 1993 and Revision B in November 2002; the original March 1976 version is the s
25、pecific reference here) 2.1.6 Oran, F. M., and Schiff, M. I.: “Design of Air-Cooled Jet Engine Testing Facilities“, Industrial Acoustics Company, Bronx, New York, 1979. 2.1.7 Ashwood, P. F., et al.: “Operation and Performance Measurements on Engines in Sea Level Test Facilities“, AGARD Lecture Serie
26、s No. 132 (AGARD-LS-132), Advisory Group for Aerospace Research and Development, North Atlantic Treaty Organization, Neuilly Sur Seine, France, 1984 SAE INTERNATIONAL AIR4869A 3 OF 142.1.8 Freuler, R. J.: “An Investigation of Jet Engine Test Cell Aerodynamics by Means of Scale Model Test Studies wit
27、h Comparisons to Full-Scale Test Results“, Ph.D. Dissertation, The Ohio State University, Columbus, Ohio, December 1991 2.1.9 Freuler, R. J.: “Recent Successes in Modifying Several Existing Jet Engine Test Cells to Accommodate Large, High-Bypass Turbofan Engines“, AIAA Paper No. 93-2542, Paper prese
28、nted to the AIAA/SAE/ASME/ASEE 29th Joint Propulsion Conference, Monterey, California, June 28-30, 1993 2.1.10 MacLeod, J. D.: “A Derivation of Gross Thrust for a Sea-Level Jet Engine Test Cell“, Division of Mechanical Engineering Report No. DM-009, National Research Council Canada, Ottawa, Ontario,
29、 1988 2.1.11 Bryan, J. J.: “Turbofan and Turbojet Engine Test Facilities Exhaust System Low Frequency Noise and Infrasound“, Engineering Report, General Electric Engine Facility Design Center, Cincinnati, Ohio, September 20, 1985 2.1.12 Karamanlis, A. I., and Pucher, S.: “Strother/Kansas CFM56/F110
30、GE Test Facility Scale Model Test“, General Electric Technical Memorandum, TM No. 85-334, GE Aircraft Engines, Cincinnati, Ohio, July 1985 2.1.13 Dickman, R. A., Hoelmer, W., Freuler, R. J., and Hehmann, H. W.: “A Solution for Aero-Acoustic Induced Vibrations Originating in a Turbofan Engine Test Ce
31、ll“, AIAA Paper No. 84-0594, Paper presented to the AIAA 13th Aerodynamic Testing Conference, San Diego, California, AIAA Conference Proceedings CP841, March 1984, pp. 99-108 2.1.14 “Gas Turbine Engine Inlet Flow distortion Guidelines“, SAE Aerospace Recommended Practice ARP1420, Society of Automoti
32、ve Engineers, Warrendale, Pennsylvania, Issued March 1978, Reaffirmed May 1991 2.1.15 “Inlet Total Pressure Distortion Considerations for Gas Turbine Engines“, SAE Aerospace Information Report AIR1419, Society of Automotive Engineers, Warrendale, Pennsylvania, Issued May 1983 2.1.16 Freuler, R. J. a
33、nd Montgomery, K. A.: “Reducing Large Pressure Fluctuations in an Engine Test Cell by Modifying the Exhaust Blast Basket End Configuration“, CEAS/AIAA Paper No. 95-128, Paper presented to the First Joint CEAS/AIAA Aeroacoustics Conference (16th AIAA Aeroacoustics Conference), Munich, Germany, Procee
34、dings of the First Joint CEAS/AIAA Aeroacoustics Conference, Vol. 2, June 1995, pp. 903-909. 2.1.17 “Inlet Airflow Ramps for Gas Turbine Engine Test Cells”, SAE Aerospace Information Report AIR5306, Society of Automotive Engineers, Warrendale, Pennsylvania, Issued July 2000 2.1.18 “Frequency-weighti
35、ng Characteristic for Infrasound Measurement”; ISO 7196:1995 2.2 Symbols and Abbreviations The following parameters, abbreviations, and subscript notations are used in this report: 2.2.1 Parameters A - cross-sectional area Cd- flow coefficient g - gravitational constant M - Mach number p - pressure
36、R - gas constant for air T - temperature V - velocity W - airflow rate a - cell bypass ratio g - ratio of specific heats SAE INTERNATIONAL AIR4869A 4 OF 142.2.2 Abbreviations AIAA American Institute of Aeronautics and Astronautics AGARD Advisory Group for Aerospace Research and Development BM bellmo
37、uth FC front cell ft/s feet per second L/D length-to-diameter ratio m/s meters per second rpm revolutions per minute SAE Society of Automotive Engineers 2.2.3 Subscripts amb ambient condition avg average BF cell bypass flow BM bellmouth Dist distortion ENG engine FC front cell flow flow function max
38、 maximum min minimum s static t total 3. TECHNICAL BACKGROUND A ground-level jet engine test cell may be defined as an enclosed structure with an engine mounting mechanism which is intended to provide conditions for stable, repeatable, and accurate engine performance testing. Turbofan and turbojet e
39、ngines operating in a test cell can encounter a number of problems which are directly attributable to the characteristics of the test cell environment. These problems can be as minor as unsteady engine speed and thrust variations. This leads directly to increased uncertainty about other engine perfo
40、rmance measurements, since many engine performance parameters are referenced either to engine inlet conditions at the compressor or fan face, or to the engine rpm. In these cases, the engine performance is unstable and not repeatable and often can cause an unnecessary test rejection and a subsequent
41、 costly rebuild. In the worst situations, more severe problems such as fan or core stalls may occur and can result in serious engine damage. The above problems are generally caused by pressure or temperature distortions arising from aerodynamic characteristics peculiar to the flow field of the test
42、cell. More specifically, the problems are related to the design of the cell inlet and exhaust systems and to the cell bypass ratio, which is the ratio of the airflow bypassing the engine completely to that which directly enters the engine inlet or bellmouth. When one test cell is used for several ty
43、pes of engines differing in configuration and orientation, in engine thrust levels, in bellmouth inlet flow requirements, and in exhaust temperatures, the probability of distorted flows with some engines is increased. And although poor cell inlet designs can obviously contribute to distortions in th
44、e flow, it is often the case that insufficient or low cell bypass flow is primarily responsible for the formation of engine-ingested vortices, which should be avoided. A modern ground-level jet engine test cell facility must be able to accommodate the larger engines of todays aircraft as well as a w
45、ide range or mix of engines types with differing thrust levels. Such a facility must also provide an aerodynamic environment of good quality for the operation of the engine, have small errors due to test cell interference effects or performance measurement instrumentation inaccuracies, and include b
46、etter acoustic treatment to minimize environmental disturbances. Enclosed test cell design concepts have evolved as turbofan and turbojet engines and their operational needs have developed, although not as rapidly. Test cell related engine operational problems can arise because the newer, higher thr
47、ust families of engines require substantially more cell airflow than earlier models. Recent research involving scale model test cells has assisted the evolution of engine test cell design and attacked the need for improved engine test facilities (2.1.1, 2.1.2, 2.1.3, 2.1.4). SAE INTERNATIONAL AIR486
48、9A 5 OF 14As an example of this evolutionary change in test cell design, consider for a moment the velocity of the airflow in the front cell region. Previously, design of guidelines usually suggested that the front cell velocity preferably be less than 32 ft/s (9.8 m/s) (2.1.5, 2.1.6, 2.1.7). The re
49、asoning was that if the airflow velocity in the test cell is significant, then the operation of the engine in the cell is equivalent to “flying“ the engine at a ram pressure ratio greater than 1.0 and at a somewhat higher altitude. Combined with the fact that there are pressure losses through the cell inlet system, it follows that the correction to engine performance measurements to sea level static standard day conditions is greater, since
