SAE AIR 5771-2015 The Measurement of Engine Thrust in an Altitude Test Facility.pdf

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1、_SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising theref

2、rom, is the sole responsibility of the user.”SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions.Copyright 2015 SAE InternationalAll rights reserved. No part of this publi

3、cation may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE.TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada)Tel: +1 724-776-4970 (out

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/AIR5771AEROSPACEINFORMATION REPORTAIR5771Issued 2015-09The Measurement of Engine Thrust in an

5、 Altitude Test FacilityRATIONALEThe aim of the document is to assemble and record the current knowledge of the use of an Altitude Test Facility (ATF) in support of In-Flight Thrust Determination (IFTD). There is a particular need to identify and understand the defined test processes that have the gr

6、eatest influence on the accuracy of the result. The document will address the key concerns and recommend best practices for optimizing them.FOREWORDThis document describes how an altitude test facility may be used for the measurement of engine thrust at simulated flight conditions in support of in-f

7、light thrust determination.Most of the major altitude facilities around the world are generally similar in construction and operation; however, at the detailed level each is unique and in attempting to provide a general description of ATF use, this document necessarily overlooks many of the details.

8、 An engineer responsible for measuring the performance of an engine using an ATF is therefore advised to take time to become familiar with the operation of the facility, its attributes and limitations.The scale, power consumption and complexity of an altitude test facility makes it more costly both

9、to operate and to maintain than a ground level test facility. This emphasizes the need for an ATF test engineer to reduce testing time to a minimum and to optimize the testing time that is used. A planned approach to test planning and on-line data assessment, making full use of on-line computing sys

10、tems is essential and is covered in this document.In order to determine thrust accurately in an ATF, it is especially important to accurately determine the air mass flow through an engine. This document describes how air flow is derived.The accuracy of an altitude test facility, in terms of thrust m

11、easurement in steady state and flight condition control in transient needs to be seen in terms of technical feasibility. Measurement uncertainty assessments are essential to understand the source of any shortfall in accuracy and how they may be addressed.Altitude test facilities also have an importa

12、nt role in many other forms of functional engine testing that are not covered in this document.SAE INTERNATIONAL AIR5771 Page 2 of 50TABLE OF CONTENTS1. SCOPE 5 1.1 Scope of the Initial Issue. 5 2. REFERENCES 6 2.1 Applicable Documents 6 2.1.1 SAE Publications. 6 2.1.2 ISO Publications 6 2.1.3 AIAA

13、Publications 6 2.1.4 ASME Publications 6 2.1.5 Applicable References 6 2.2 Nomenclature 7 2.2.1 Fundamental Parameters 7 2.2.2 Greek Parameters. 7 2.2.3 Parameters Used In This Document. 7 2.2.4 Abbreviations 8 2.3 Use of SI (Metric) Units. 9 3. DESCRIPTION OF ALTITUDE TEST FACILITY 9 3.1 Overview o

14、f the ATF . 9 3.2 Test Cell Air Supply Systems 11 3.3 Inlet Duct . 12 3.3.1 Overview . 12 3.3.2 Slip Joint 13 3.3.3 Effects of Air Humidity. 13 3.4 Thrust Stand 14 3.4.1 Overview . 14 3.4.2 The Engine Support 15 3.4.3 The Floating Frame or Thrust Bed 15 3.4.4 Axial Data Load Train 15 3.4.5 Axial Cal

15、ibration Load Train 15 3.4.6 Ground Frame. 15 3.4.7 Vertical Support Columns . 15 3.4.8 Lateral Supports 15 3.4.9 Safety Stops 15 3.4.10 Load Cells . 16 3.4.11 Thrust Stand Distortion . 16 3.5 Test Cell Chamber 17 3.6 Test Cell Exhaust Systems . 18 3.7 Measurement Systems . 19 3.7.1 Overview . 19 3.

16、7.2 Pressure 19 3.7.3 Temperature 20 3.7.4 Force . 20 4. TEST OPERATIONS 20 4.1 Test Program 20 4.1.1 Project Plan. 21 4.1.2 Technical. 22 4.1.3 Test Optimization 23 4.2 Testing. 25 4.2.1 Monitoring . 25 4.2.2 Data Recording . 25 4.2.3 Test Log 25 4.2.4 Measurement Log . 26 4.2.5 Results 26 SAE INTE

17、RNATIONAL AIR5771 Page 3 of 504.2.6 Reporting. 26 4.2.7 Comparison with Expectations 26 4.2.8 Lessons Learned. 26 4.3 Data Assessment 26 4.3.1 Overview . 26 4.3.2 Flight Conditions . 26 4.3.3 Assessment of Flight Conditions. 27 4.3.4 Influence Coefficients (Sensitivity) 27 4.3.5 Data Assessment Meth

18、ods . 28 5. TECHNICAL DISCUSSION 30 5.1 Overview . 30 5.2 Air Mass Flow Determination 30 5.2.1 General Principles. 30 5.2.2 Air Mass Flow Measurement Using an Air Meter . 31 5.2.3 Air Mass Flow Measurement Using an Array of Venturis . 35 5.2.4 Additional Mass Flow Measurement. 39 5.3 Approach Duct a

19、nd Slip Joint 39 5.3.1 Overview . 39 5.3.2 Total Pressure. 39 5.3.3 Static Pressure 40 5.3.4 Duct Losses 40 5.3.5 Slip Joint 40 5.4 Derivation of Thrust. 43 5.4.1 Overview . 43 5.4.2 Principles of the Gross Thrust Equation . 44 5.4.3 Gross Thrust Calculation in Practice. 44 5.4.4 Net Thrust . 45 5.5

20、 Correction of Data to Nominal Conditions. 45 5.5.1 Overview . 45 5.5.2 Look-Up Tables. 46 5.5.3 Quasi-Dimensionless Groups . 46 5.5.4 Performance Model Based Referrals 46 5.6 Measurement Uncertainty. 46 5.6.1 Overview . 46 5.6.2 Defined Measurement Process. 46 6. NOTES 48 6.1 Revision Indicator 48

21、APPENDIX A USE OF NON-SI (METRIC) UNITS 49 Figure 1 General arrangement of an ATF . 9 Figure 2 Typical flight envelope for a subsonic transport aircraft 10 Figure 3 Generic air supply system. 11 Figure 4 Inlet duct 12 Figure 5 Slip joint detail (without seal) 13 Figure 6 Floor-mounted thrust stand.

22、14 Figure 7 Overhead thrust stand. 15 Figure 8 Altitude test cell chamber 17 Figure 9 Exhaust system. 18 Figure 10 Outline program 20 Figure 11 Example profile plots. 29 Figure 12 Example performance plots 29 Figure 13 Single air meter in inlet duct 32 Figure 14 Single venturi tube 35 Figure 15 Vent

23、uri flow coefficient 36 Figure 16 Venturi array 37 Figure 17 Venturi pressure ratio characteristics 38 SAE INTERNATIONAL AIR5771 Page 4 of 50Figure 18 Venturi pressure loss curves. 38 Figure 19 Slip joint with seals 42 Figure 20 Relative contributions to net thrust 45Table 1 Effect of +1% error in i

24、nputs on thrust and SFC results . 28Table 2 Slip joint design considerations. 41 SAE INTERNATIONAL AIR5771 Page 5 of 501. SCOPE1.1 Scope of the Initial IssueThis report covers engine tests performed in Altitude Test Facilities (ATFs) with the primary purpose of determining steady state thrust at sim

25、ulated altitude flight conditions as part of the in-flight thrust determination process. As such it is complementary to AIR1703 and AIR5450, published by the SAE E-33 Technical Committee. The gross thrust determined using such tests may be used to generate other thrust-related parameters that are fr

26、equently applied in the assessment of propulsion system performance. For example: net thrust, specific thrust, and exhaust nozzle coefficients.The report provides a general description of ATFs including all the major features. These are:x Test cell air supply system. This controls the inlet pressure

27、 and includes flow straightening, humidity and temperature conditioning.x Air inlet duct and slip joint. Note that the report only covers the case where the inlet duct is connected to the engine, not free jet testing.x Thrust stand force measurement systemx Test cellx Cell exhaust systemx Measuremen

28、t systemThe report provides detailed technical information on how the facilities are operated, including:x Program planning guidelinesx Optimization of the testsx Setting and control of flight conditionsx Assessment of the dataA technical discussion provides the underlying physics for:x Air mass flo

29、w determinationx Determination of the conditions in the inlet duct and slip jointx Derivation of thrust and related parametersx Correction of data to nominal flight conditionsx Measurement uncertaintyThe initial issue of this report primarily address ATF testing of engines intended for use on subson

30、ic, transport aircraft.Future revisions to the report will include greater content relevant to the testing of engines for supersonic aircraft, including the wider and higher flight envelopes associated with such aircraft and the technical issues raised by these flight conditions.SAE INTERNATIONAL AI

31、R5771 Page 6 of 502. REFERENCES2.1 Applicable DocumentsThe following publications form a part of this document to the extent specified herein. The latest issue of SAE publications shall apply. The applicable issue of other publications shall be the issue in effect on the date of the purchase order.

32、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.2.1.1 SAE PublicationsAvailable from SAE Int

33、ernational, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or +1 724-776-4970 (outside USA), www.sae.org.SAE Technical Standards Board Governance PolicySAE Aerospace Council of the SAE Technical Standards Board - Organization and Operating Procedures (R)

34、AS755 Aircraft Propulsion System Performance Station DesignationAIR1678 Uncertainty of In-Flight Thrust DeterminationAIR1703 In-Flight Thrust DeterminationAIR5450 Advanced Ducted Propulsor In-Flight Thrust DeterminationAIR5925 Measurement Uncertainty Applied to Cost-Effective Testing2.1.2 ISO Public

35、ationsAvailable at http:/webstore.ansi.org/ISO 2533:1975 Standard Atmosphere2.1.3 AIAA PublicationsAvailable from American Institute of Aeronautics and Astronautics, 1801 Alexander Bell Drive, Suite 500, Reston, VA 20191-4344, Tel: 703-264-7500, www.aiaa.org.AIAA 99-0304 Experimental measurement of

36、Venturi discharge coefficient including sensitivity to geometric and flow qualities variables, D.K. Beale.AIAA 93-2452 Engine Testing at Simulated Altitude Conditions, J.H. Roberts, B Mancuso, J. Babilon, M McIlveen, 19932.1.4 ASME PublicationsAvailable from ASME, P.O. Box 2900, 22 Law Drive, Fairfi

37、eld, NJ 07007-2900, Tel: 800-843-2763 (U.S./Canada), 001-800-843-2763 (Mexico), 973-882-1170 (outside North America), www.asme.org.ASME PTC19.1:2013 Test Uncertainty2.1.5 Applicable ReferencesThermodynamics by E. F. Obert and R. A. Gaggioli, McGraw and Hill, 1963Gas Turbine Performance by P. Walsh a

38、nd P. Fletcher, Blackwell Science, 1998SAE INTERNATIONAL AIR5771 Page 7 of 502.2 NomenclatureThe nomenclature listed below applies to this document. The list partly derives from AS755D (Aircraft Propulsion System Performance Station Designation and Nomenclature).2.2.1 Fundamental ParametersA= AreaF

39、= ForceM = Mach NumberP = Pressurer = radiusT= Temperaturet = TimeV= VelocityW = Mass Flow Rate2.2.2 Greek Parameters. = Coefficient of Thermal Expansion = Ratio of Specific Heat Capacities/ = Partial Derivative or Inlet Pressure Ratio = Influence Coefficient or Inlet Temperature Ratio = Kinematic V

40、iscosity! = Density2.2.3 Parameters Used In This DocumentAn = Area at location nAT = Geometric area corrected for thermal expansionCD = Discharge coefficientCVF = Venturi flow coefficientDI = DiameterFG = Gross thrustFM = Measured thrust stand force (aka frame reaction force)SAE INTERNATIONAL AIR577

41、1 Page 8 of 50FN = Net thrustgc = Gravitational unit conversion factorM0 = Flight mach numberMn = Mach number at location nPTn = Stagnation pressure at location nPSn = Static pressure at location nPSCELL = Wall pressure in the test cellR = Gas constant for airRE = Reynolds numberRx = Radius at locat

42、ion xSFC = Specific fuel consumptionTM = Material temperatureTSn = Static temperature at location nTTn = Stagnation temperature at location nWAn = Air mass flow rate at location nWAIS = Isentropic air mass flow rate2.2.4 AbbreviationsATF = Altitude Test FacilityCFD = Computational Fluid DynamicsGLTF

43、 = Ground Level Test FacilityIFTD = In-Flight Thrust DeterminationISA = International Standard AtmosphereRTD = Resistance Temperature DetectorSI = Systme International (dUnits)SL = Sea LevelSLS = Sea Level StaticSAE INTERNATIONAL AIR5771 Page 9 of 502.3 Use of SI (Metric) UnitsThis document conforms

44、 with the SAE Policy regarding the use of SI (metric) units as defined in SAE Technical Standards Board Standard Governance Policy, TSB003 and in the Organization and Operating Procedures of the SAE Aerospace Council.The application of this policy implies that formulae must be set out as if SI units

45、 are being used. However, it is common within the aerospace industry to employ English units, for which the use of the gravitational unit conversion factor, gc, is necessary. For example the equation:() = 9 8 +# (2 5F2 4)is correct when using SI units and is equivalent to:() =9 8C+# (2 5F2 4)when En

46、glish (Imperial) units are used.Accordingly, it is important that the reader applies the gravitational factor appropriately. Many references exist for this:“Thermodynamics” by Obert and Gaggioli is a good example.Appendix A provides the correct formulae to be used with English units.3. DESCRIPTION O

47、F ALTITUDE TEST FACILITY3.1 Overview of the ATFThe atmosphere in which all aero engines must work is not of constant pressure, temperature or density. Consequently, the performance of engines will vary with changes in any of these properties. Therefore, it is necessary for an engine manufacturer to

48、determine variations in the characteristics of an engine due to the atmospheric conditions using a number of different tools - one of which may be the altitude test facility. A generic diagram of an ATF is shown in Figure 1.Figure 1 - General arrangement of an ATFWhile pressure, temperature and dens

49、ity of the air in the earths atmosphere all generally fall with increasing altitude, they are also affected by local climatic conditions that introduce fluctuations in these properties and the effects of humidity. In order to set aside such meteorological variations, an International Standard Atmosphere (ISA) is used to define standard, static, conditions. The International Standard At