1、AEROSPACERECOMMENDEDPRACTICEARP1665REV.AIssued 1983-03Revised 1997-12Superseding ARP1665Definition of Pressure Surge Test andMeasurement Methods for Receiver AircraftFOREWORDChanges in this revision are format/editorial only.TABLE OF CONTENTS1. SCOPE .12. REFERENCES .23. CRITICAL PARAMETERS34. SURGE
2、 PRESSURE DEFINITION.55. INSTRUMENTATION56. PRETEST CALIBRATION 67. TEST PROCEDURE.78. SYSTEM SIMULATION 81. SCOPE:The test procedure applies to the refueling manifold system connecting the receiver aircraft fuel tanks to the refueling source fuel pump(s) for both ground and aerial refueling. The te
3、st procedure is intended to verify that the limit value for surge pressure specified for the receiver fuel system is not exceeded when refueling from a refueling source which meets the requirements of AS1284 (reference 2). This recommended practice is not directly applicable to surge pressure develo
4、ped during operation of an aircraft fuel system, such as initiating or stopping engine fuel feed or fuel transfer within an aircraft, or the pressure surge produced when the fuel pumps are first started to fill an empty fuel manifold.SAE Technical Standards Board Rules provide that: “This report is
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8、tp:/www.sae.org Reaffirmed 2007-12SAE ARP1665 Revision A- 2 -1.1 Purpose:The need for large fuel loads requires high refueling rates for both ground and aerial refueling to minimize refueling time. Stopping the high refueling fuel velocity in a short period of time causes a pressure in the refueling
9、 system (both aircraft systems and refueling equipment) higher than the normal operating pressure. This higher pressure, called surge pressure, or water hammer, is described in reference 1, section 3.10, “Fluid Transients.” The intensity of the surge pressure is dependent upon the interaction betwee
10、n the aircraft refueling system and the refueling source system. This document establishes a standard procedure for testing an aircraft refueling system when combined with a refueling source (refueling truck, hose cart, hydrant system, or aerial refueling tanker) to verify that the surge pressure wi
11、thin the receiver aircraft does not exceed the value specified for the system.2. REFERENCES:1) Aerospace Fluid Components Designers Handbook, Revision C, Technical Documentary Report No. RPL-TDR-64-25, November 1968.2) AS1284, Standard Test Procedure and Limit Value for Shutoff Surge Pressure of Pre
12、ssure Fuel Dispensing Systems3) Coordinating Research Council (CRC) Aviation Handbook, Fuels and Fuel Systems, NAVAIR06-5-504, dated 1 May 19674) MIL-F-87154 (USAF), Fuel Systems, General Design Specification, dated 15 Aug 80.5) MIL-F-17874B, Fuel Systems: Aircraft Installation and Test of; dated 20
13、 Aug 656) MIL-T-83219 (USAF), Truck Tank A/S32R-97) Fuel Transient Analysis (FUELTRAN) Computer Program Technical Memorandum,ENFEF-TM-81-03, dated March 1981.8) Aircraft Hydraulic System Transient Analysis (HYTRAN) Report MDCA3060, Revision A, dated 3 March 1975.SAE ARP1665 Revision A- 3 -3. CRITICA
14、L PARAMETERS:3.1 Refueling Source:1. Refueling source pump(s) characteristics (pressure versus flow) measured at the inlet of the refueling nozzle or refueling coupling.2. Pressure or flow regulator characteristics (if applicable).3. Surge damper characteristics (if applicable).4. Check valve charac
15、teristics (if applicable).3.2 Receiver Aircraft:1. Pressure drop versus flow characteristics (including pressure drop versus flow of refueling source nozzle or coupling).2. Shutoff or level control valve characteristics (closure time versus flow rate at beginning of closure and rate of flow area cha
16、nge during closure).3. Surge damper characteristics (if applicable).4. Pressure or flow regulator characteristics (if applicable).5. Check valve characteristics (if applicable).SAE ARP1665 Revision A- 4 -3.3 Combined System:1. Length of combined refueling source piping and aircraft receiver system p
17、iping.2. Pressure wave velocity through combined systems. The pressure wave velocity can be estimated by the following equations which illustrate the relationship of the system parameters and the material properties.(Reference 1 Equation 3.10.3C)Where: Vs = Velocity of pressure waves, ft/secondW = S
18、pecific weight, lbf/ft3B = Bulk modulus of fluid, lbf/in2d = Pipe inside diameter, inchE = Modulus of elasticity of pipe, lbf/in2b = Pipe wall thickness, inchThe value of the pressure wave velocity for a compound system consisting of several pipes of different diameters in series, wall thickness and
19、 material can be estimated as follows:(Reference 3, paragraph 2.4.5.2.5)Where: Vse = Equivalent pressure wave velocity for compound system, ft/second1t= Total length of pipe, ft11, 12, 13= Length of particular section, ftVs1, Vs2, Vs3= Pressure wave velocity of particular section, ft/secondVs68.094W
20、1B-dEb-+-=Vse1t11Vs1-12Vs2-13Vs3-+-=SAE ARP1665 Revision A- 5 -4. SURGE PRESSURE DEFINITION:Surge pressure is generally defined as a transient pressure rise or fall in fluid pressure, usually as a result of operation of system valves. For receiver system testing, surge pressure limit is defined as t
21、he total pressure anywhere within the receiver system consisting of the normal static fuel pressure, plus the incremental pressure rise resulting from valve closure. The parameter of interest is the total pressure in the system, and not the value for the normal and surge components of the total pres
22、sure.References 4 and 5 use the term surge pressure or maximum surge pressure for the limit of total pressure which occurs when fuel flow is stopped or reduced within the system.5. INSTRUMENTATION:Quantity and LocationSufficient pressure measurement points should be provided in the system to charact
23、erize the surge pressure wave in the system. A pressure measurement should be made just downstream of the pump(s) and at a point approximately midway between the flow cutoff instrumentation point(s) and the pump(s) instrumentation point(s). Additional pressure measurements should be added at any pos
24、ition considered critical for the system. A pressure measurement should be made at the dead end of any side branch of the main flow line.Multiple pressure measurement points allow the pressure wave to be identified and the wave speed to be verified as well as providing backup capability in case of p
25、ressure transducer failure.A pressure versus time trace obtained from a measurement point just upstream of a flow cutoff valve will exhibit fewer pressure increase/decrease cycles during the valve closure than a trace taken from an instrumentation point closer to the pumps. Slow closing shutoff valv
26、es may produce only one major pressure increase/decrease cycle during the valve closure. Pressure measurements taken upstream of the shutoff valve should exhibit the period of the pressure wave and produce several pressure increase/decrease cycles during the valve closure.Strain gages may be desired
27、 for installation on the fuel tube near the shutoff valve or other critical areas in the system. This instrumentation would provide a backup if other transducers in the system are lost or are overcome by noise, interference or air bubbles.SAE ARP1665 Revision A- 6 -5. (Continued):ResponseThe instrum
28、entation should have sufficient response to measure the pressure pulse resulting from rapid valve closure. A rapid valve closure is when closure time T is equal to or less than 2L/Vs (Reference 1)Where L = pipe length from shutoff valve to refueling source pumpVs = effective pressure wave velocityA
29、pressure transducer of the strain gage type with a response in the order of 1 to 10 milliseconds is recommended with the pressure recorded in a continuous trace using a galvanometer light beam type oscillograph with a response time compatible with the pressure transducer. This type equipment is spec
30、ified by references 4 and 6. A minimum paper speed of 1 inch per second should be used to provide a good display of the pressure trace.Transducer Location, Accuracy and RangePressure transducer entrance points should be located to minimize the effects of air in the system and cavitation bubbles or e
31、ddying turbulence. A pick-up point on the side of the line is recommended. In pick-up point selection, consider the effects of close proximity to sharp bends or a line expansion or reduction. Verify, by static pressure calibration that the error of the transducer and recorder measured at 120 psig (8
32、30 kPa) is not greater than 1%. The range of the pressure transducer/recorder should be suitable for the ultimate pressure rating of the system.6. PRETEST CALIBRATION:Each refueling source to be used in testing a receiver system should be pretested in accordance with AS1284 (reference 2). This stand
33、ard requires the use of a test system incorporating a test shutoff valve which closes “within 0.5 seconds in a near linear manner.” AS1284 does not define “near linear manner,” however, it is generally interpreted to mean a linear change of flow area with respect to time.A tolerance or allowable dev
34、iation from linear is not specified.The flow area reduction characteristics of the test shutoff valve during the 0.5 second interval is critical.The flow area (or poppet/gate position) versus time of the test shutoff valve should be measured during the pretest for all flow rates expected during the
35、test to determine the extent of deviation from the specified near linear closure.With an actual refueling source or an accurate simulation of the refueling source(s) and a detailed characterization of the test shutoff valve, the worst case refueling source need not be fabricated and tested, however,
36、 this case can be evaluated analytically for effect on the receiver system. A transient analysis technique using a digital simulation process has been developed which treats the fluid lines with distributed parameters, applying the concepts of wave mechanics and including the effects of nonlinear fr
37、iction. The fluid line equations are solved with the help of the method of characteristics. A Fuel Transient Analysis (FUELTRAN) computer program (reference 7) has been developed by the Air Force using as a basis the Hydraulic Transient Analysis Program (HYTRAN) (reference 8).SAE ARP1665 Revision A-
38、 7 -6. (Continued):Using this approach to obtain a computer simulation match of the actual test condition, the computer simulation of the refueling source can be modified to evaluate the effects of the worst case refueling source.Prior to conducting the surge test, the following stead state data sho
39、uld be measured on the test hardware:a. Pressure versus flow of the refueling source measured at the inlet to the refueling nozzle or refueling coupling.b. Pressure drop versus flow for the receiver system, including the pressure drop of the refueling nozzle or refueling coupling. Data should be mea
40、sured for each receiver fuel tank open singularly and all likely tank open combinations.c. Flow area versus time during closure for each flow control valve in the receiver system (both fuel level control valves and system isolation valves) for flow/pressure ranges to be encountered in service. The p
41、ressure distribution across the poppet of a fuel level control valve is critical in relation to the valve closure time, therefore, the test hardware preceding the valve inlet should duplicate the aircraft installation.For fuel level control valves which have a surge relief feature, the cracking pres
42、sure and main poppet response time should be determined.7. TEST PROCEDURE:Conduct pressure surge tests by establishing maximum stabilized fuel flow for the specified tank open condition for a minimum of 10 seconds and then stopping the fuel flow by closing the shutoff valve.Each mode of closing the
43、valves (primary and secondary solenoid, precheck activation, etc.) should be tested to determine the most critical (fastest) closure mode. Tests should be repeated until repeatable data are obtained for the test condition. Maximum fuel flow is obtained by applying rated refueling operating pressure,
44、 normally 55 psig (380 kPa), to the inlet of the refueling connection. Actual refueling source hardware may not have sufficient flow capacity to maintain rated refueling operating pressure at the inlet to the refueling connection, especially for high capacity, low pressure drop receiver systems. Sur
45、ge test results from an insufficient capacity refueling source cannot be extrapolated to verify surge compatibility for higher capacity refueling sources.Measure surge pressure under the following conditions:a. Each tank refueling individually - Close level control valveb. All tanks refueling simult
46、aneously - Close system isolation valveSAE ARP1665 Revision A- 8 -7. (Continued):c. Combinations of tanks refueling (tank combinations which will give the greatest velocity reduction per valve closure time). Close level control valves simultaneously.d. Emergency modes such as failure of relief valve
47、s or surge suppressors in the receiver or refueling source.8. SYSTEM SIMULATION:Actual refueling source systems and receiver systems should be used for surge testing. However, due to non-availability of production hardware in the required time frame, a simulation of the receiver system and refueling
48、 source may be required. The simulation should include as much as possible of the actual production hardware (pumps, valves, regulators, connectors, piping, etc.). In the following list are parameters which influence surge levels in a flowing system, listed in what is considered to be their approxim
49、ate relative order of importance:1) Flow control valve closure time and flow area reduction characteristics2) Pump pressure and flow response characteristics3) Surge relief devices, air pockets or traps in system.4) Line length - for given valve closure rate and characteristic5) Line diameter - affects surge by determining velocity for given flow rate.6) Line stiffness - made up of:a. Line materialb. Line wall thicknessc. Connector expansiond. Line rigidity (
