1、SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and enginee ring sciences. The use of this report is entirelyvoluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefr
2、om, is the sole responsibility of the user.”SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invit es your written comments and suggestions.Copyright 1997 Society of Automotive Engineers, Inc.All rights reserved. Printed in U.
3、S.A.QUESTIONS REGARDING THIS DOCUMENT: (412) 772-8510 FAX: (412) 776-0243TO PLACE A DOCUMENT ORDER: (412) 776-4970 FAX: (412) 776-0790400 Commonwealth Drive, Warrendale, PA 15096-0001AEROS PACE INFORM ATION REPORTSubmitted for recognition as an American National StandardAIR984 RE V. CIssued 1969-04R
4、eaffirmed 1989-05Revised 1997-05Superseding AIR984BA ir B leed O bjective for H elicopter T urbine E nginesFOREWORDChanges in this revision are format/editorial only.1. SCOPE:This SAE Aerospace Information Report (AIR) defines the helicopter bleed air requirements which may be obtained through compr
5、essor extraction and is intended as a guide to engine designers.2. REFERENCES:There are no referenced publications specified herein.3. GENERAL:3.1 Bleed air on helicopter installations may be used as a source of heated air for the following purposes:a. Engine inlet de-icing and anti-icingb. Cabin co
6、nditioning and pressurizationc. Windshield de-fogging, de-frosting, and anti-icing3.2 A secondary use is for a small power source for driving one to two accessories and possible cross starting for multi-engine installation.SAE AIR984 Revision C- 2 -4. DISCUSSION:4.1 It is recognized that, in general
7、, compressor bleed air is an inefficient source of power. It is necessary, therefore, to limit bleed extraction to those uses in which an overall advantage to the helicopter will accrue. As a source of energy for those applications listed in and , bleed air performs a service that could otherwise re
8、quire considerably more equipment with increased weight, cost, size, and complexity; otherwise, its use should be limited to the conditions where the reduction in engine power is not detrimental to helicopter performance. This document is not all encompassing and the engine manufacturer should consi
9、der specific bleed air requirements for engine ground idle operation with the helicopter rotor locked.4.2 If the use of bleed air for cabin conditioning during hot weather proves desirable to overall helicopter optimization, it is recommended that engine designers consider anticipated compressor ble
10、ed air need.5. DEFINITIONS:5.1where:W BL = Weight of bleed air in pounds/hour (kg/s)C p = Specific heat at constant pressure in BTU/lb - F (KJ/kg - C)T BL = Bleed port air temperature, F (C)T ambient = Freestream air temperature, F (C)Bleed Energy = BTU/hour (KW)5.2 Assume sea level or note if other
11、wise.6. QUALITATIVE OBJECTIVE:6.1 To be acceptable for the purpose of cabin conditioning and pressurization, the bleed air must be free of detrimental contamination. The engine manufacturer should address the problem of bleed air contamination resulting from compressor bearing seal failures. This re
12、quirement is imposed on FAA certificated helicopters by FAR 29.831 (b) and (d). Approved test methods for assaying air samples may be obtained from one of the following:a. American Industrial Hygiene Association, 14125 Prevost, Detroit, Michigan - Request “Hygiene Guide for (name of substance).“b. “
13、The Chemistry of Industrial Toxicology,“ 2nd edition - Henry B. Elkins, John Wiley and Son, Inc., 1959, Chapter 17, pp 280-416, Analytical Methods and Procedures.c. “Analytical Chemistry of Industrial Poisons, Hazards and Solvents,“ M. B. Jacobs.d. “Chemical Methods in Industrial Hygiene,“ F. H. Gol
14、dman, M. B. Jacobs, Interscience Publisher, 1953.e. MIL-E-8593A.BTU/hour (KW)WBLCp TBLTambient()=SAE AIR984 Revision C- 3 -7. QUANTITATIVE OBJECTIVE:7.1 The primary requirement for bleed air is for environmental control. It is expedient to specify the requirement in terms of BTU per hour per horsepo
15、wer. This leaves the pressure, temperature, and mass flow at which bleed air is supplied to the discretion of the engine designer. It is desirable to provide the same bleed energy determined from the curves in Figure at all gas generator operating conditions down to flight idle power (i.e. 100% powe
16、r turbine speed zero output torque). Specific stated engine operating conditions may require other considerations. Currently, helicopter environmental control units require bleed air at entry pressure levels of 3 to 4 atmospheres.7.2 Figure shows a range of heat requirements as a function of the amb
17、ient temperature. Curve A is a minimum requirement for de-icing or anti-icing for an airframe induction system. Curve B shows the relationship of bleed energy requirements for cabin conditioning.7.3 It is considered that the objective for future engine designs is to provide bleed capacity described
18、by the total of curves A and B. The quantities of energy recommended by curves A and B may collectively amount to an impractically large flow of compressor bleed air when applied to certain low pressure ratio engines. In such cases, it is recommended that the engine designer provide at least suffici
19、ent air for curve A.7.4 Generally, the extraction of bleed air for the purpose of driving accessories is not recommended, principally for the reason that helicopter hot day performance is affected adversely. Satisfactory installation may be possible in the case of accessories requiring bleed air onl
20、y while on the ground or where the power required is very small. It is not considered necessary to stipulate an additional increment of bleed air for these purposes beyond the heating requirements. Any continuous power demand for running accessories is considered an individual installation problem a
21、nd beyond the scope of this information report.7.5 The engine manufacturer should take the responsibility of precluding surge or other engine malfunctions anywhere within the specified bleed air extraction range. It is desirable that the engine be provided with automatic safeguards to preclude detri
22、mental engine overtemperature during bleed air usage.7.6 It is desired that the engine manufacturer provide a single bleed port at each compressor station for which bleed is available. A single bleed port minimizes the complexity of the helicopter pneumatic plumbing; therefore, full bleed capability
23、 should be available from any single port.7.7 The engine manufacturer should establish a maximum bleed flow allowable for the failed airframe plumbing condition.SAE AIR984 Revision C- 4 -8. NOTES:The change bar ( l ) located in the left margin is for the convenience of the user in locating areas whe
24、re technical revisions, not editorial changes, have been made to the previous issue of this document. An (R) symbol to the left of the document title indicates a complete revision of the document.PREPARED BY SAE COMMITTEE S-12, HELICOPTER POWERPLANTSAE AIR984 Revision C- 5 -FIGURE 1 - Helicopter Bleed Air Requirements at 100% Normal Rated Power(Maximum Continuous)
