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4、0 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/ARP699EAEROSPACERECOMMENDED PRACTICEARP699 REV. E Issued 1960-02 Revised 1997-12R
5、eaffirmed 2015-11 Superseding ARP699D High Temperature Pneumatic Duct Systems for Aircraft RATIONALE ARP699E has been reaffirmed to comply with the SAE five-year review policy. FOREWORDChanges in this revision are format/editorial only.TABLE OF CONTENTS1. SCOPE .32. REFERENCES .33. TERMINOLOGY .34.
6、INSTALLATION CRITERIA AND LIMITATIONS .74.1 Introduction 74.1.1 Structural Deflections .74.1.2 Thermal Expansion 74.1.3 Thermal Shock.84.1.4 Space Allocation 84.1.5 Additional Duct Load Considerations.84.1.6 Typical Duct Material94.1.7 Fluid Flow Considerations94.1.8 Environment.104.1.9 Maintenance
7、Requirements .134.1.10 Installation Tolerances144.1.11 Reliability154.2 Types of Duct Systems 164.2.1 Tension.174.2.2 Compression174.2.3 Tension-Compression 17TABLE OF CONTENTS (Continued)5. DUCT SYSTEM AND DUCT COMPONENT DESIGN CRITERIA195.1 Design Criteria195.1.1 Ducts 195.1.2 Compensation Devices
8、 for Thermal Expansion .325.1.3 Compensation Devices for Airframe Deflection, Growth and Contractionfrom Temperature Effects, and Installation Tolerances 495.1.4 Duct Coupling Requirements .525.1.5 Duct System Design Loads695.1.6 Duct System Supports .705.1.7 Thermal Insulation .725.2 Qualification
9、Requirements775.2.1 Qualification of Components775.2.2 System Qualification 945.3 Production Inspection Requirements .975.3.1 Duct Components 975.3.2 Insulation975.3.3 Installed System.986. FIELD MAINTENANCE AND INSPECTION CRITERIA .986.1 Introduction 986.2 Recommended Check Points.986.2.1 New Duct
10、Systems.986.2.2 Preflight Inspection 1006.2.3 Inflight Inspection .1006.2.4 Post Flight Inspection.1006.2.5 Progressive or Periodic Maintenance 1016.2.6 General Comments103SAE INTERNATIONAL ARP699E 2 OF 1031. SCOPE:This Recommended Practice is intended to outline the design, installation, testing, a
11、nd field maintenance criteria for a high temperature metal pneumatic duct system, for use as a guide in the aircraft industry. These recommendations are to be considered as currently applicable and necessarily subject to revision from time to time, as a result of the rapid development of the industr
12、y.2. REFERENCES:WADC Technical Report 56-187, dated September 1956, “Investigation of Aircraft Ducting Components at High Subsonic Speeds”Air Force Aero Propulsion Laboratory Technical Report 71-86, dated November 1971, “Ignition of Aircraft Fluids by Hot Surfaces Under Dynamic Conditions”3. TERMINO
13、LOGY:BELLOWS: A convoluted unit consisting of one or more convolutions used to obtain flexibility.BELLOWS, BRAIDED: A convoluted unit surrounded by a woven wire sleeve attached to the ends which restricts the movements of the unit.BELLOWS, FREE: A convoluted unit which does not incorporate any devic
14、e or part for the purpose of restricting movement.BELLOWS, RESTRAINED: A convoluted unit incorporating a means of restraint, other than braid, to prevent axial movement.BLEED AIR: Air extracted from the compressor of a gas turbine engine or propulsion unit.BLEED PORT: An outlet in the gas turbine co
15、mpressor casing through which air is extracted or bled from the compressor.BRACKET: A support or structural part which attaches and holds a duct to the vehicle structure.BRACKET, ADJUSTABLE: A bracket that allows some freedom in the location of the duct, which it supports, during installation. After
16、 the duct is located satisfactorily, the bracket is tightened and the duct is held fixed.BRACKET, ANCHOR: A main duct support at a point on the duct system that remains fixed in respect to duct system expansions, contractions or deflections.BRACKET, GUIDE: A support designed to provide for movement
17、of a duct in a predetermined direction while supporting it in all other directions.BRACKET, SLIDING: A bracket which allows a duct to slide in a controlled direction while supporting it in all other directions.SAE INTERNATIONAL ARP699E 3 OF 1033. (Continued):BRACKET, SWING: A linkage which supports
18、a duct and allows movement along the arc of the swing-ing bracket.BRAID: Woven wire sleeving used to limit movements of a bellows.BULKHEAD SEAL: A fitting allowing the passage of a duct through a wall or bulkhead to prevent the leakage through the bulkhead around the outer periphery of the duct.BY-P
19、ASS: A duct that conveys air around a system or system components.CAP, PRESSURE: A part which can be used to cover tightly the end of a duct to sustain the internal pressure.CAP, PROTECTIVE: A part used to cover an end or opening in a duct for the purpose of excluding for-eign matter.CLAMP: A normal
20、ly circular device which adjusts the circumferential length of the band. it is used to bind two members together by the exertion of radial pressure.COMPRESSION SYSTEM: A duct system wherein the fluid column loads due to internal pressure are reacted by the support structure.COUPLING: A fitting or cl
21、amping device that serves to join the mating ends of adjacent ducts or other components.DEFLECTION: A displacement of a duct or joint due to operating conditions.DUCT: An enclosed passageway made of sheet metal or other suitable material for the conveyance of fluids.DUCT ASSEMBLY: Detail parts fitte
22、d and joined together to form an integral part.EXPANSION, THERMAL: Duct growth due to an increase in temperature.FLEX-SECTION: These devices when incorporated in a duct system permit relative motion in one or more planes. The term “flex-section” may include bellows, flexible sections and flexible jo
23、ints which are devices possessing flexibility resulting from the method of construction or the utilization of flexible materials.HALF-SHELL: Die-formed duct halves.HEAT RING: A ring or flange used between the duct and support to reduce the transfer of heat from the ducts to the supporting structure.
24、SAE INTERNATIONAL ARP699E 4 OF 1033. (Continued):HOSE: Tubing, either flexible by construction or made of flexible material, which is attached to the ends of adjacent ducts, tubes or fittings. The term generally implies flexible tubing with a length to diameter ratio (L/D) of three (3) or greater.IN
25、STALLATION: A completed set of duct assemblies and duct supports incorporated in a vehicle.INSULATION: A material (applied around the duct) which is used to reduce heat exchange.JOINT: A device or complete assembly which unites or establishes continuity between adjacent ducts or other components.JOI
26、NT, BALL: A joint which permits relative angular movement and rotation of two adjacent ducts.JOINT, COMPENSATING: A pressure (thrust) compensated assembly allowing axial motion which maintains the duct walls in tension.JOINT, EXPANSION: Any of many types of joints which can permit axial movement wit
27、hout failure and therefore permit the duct system to expand or contract.JOINT, FLEXIBLE: A non-rigid joint, convoluted tubing, hose or ball joint assembly which joins two ducts and permits relative motion of the ducts in one or more planes.JOINT, RESTRAINED: A flex-section assembly in which an angul
28、ar deflection can occur with a tension load being transmitted by an external or internal device.JOINT, ROTARY: A joint which permits relative rotation of two adjacent ducts.JOINT, SLIP: A joint having sleeve assemblies, one sliding inside the other, to allow axial motion.LINE MOUNTING: Refers to a c
29、omponent mounted on and supported by the duct, instead of direct attachment to a support or bracket.LINEAR OFFSET: Distance between the duct centerlines of two joining ducts.LINER: A cylindrical part within a flex-section assembly.LIVE LENGTH: The convoluted length of a flex-section assembly.LOAD: T
30、he resultant force exerted upon restraining brackets (and structure) due to internal fluid static and dynamic pressures, thermal expansion or contraction, structural deflection, and component weight.LOAD, LIMIT: The maximum combined load due to all internal and external pressure and forces that a du
31、ct or duct system can encounter at any time in service.SAE INTERNATIONAL ARP699E 5 OF 1033. (Continued):LOAD, PNEUMATIC: The force determined by the product of the internal differential pressure and the duct cross-sectional area.LOAD, PRE-: The force imposed on a duct or duct system prior to, or dur
32、ing, installation.LOAD ULTIMATE: The maximum load on a duct or duct system can sustain without failure.MISALIGNMENT: Error in alignment between the axes of two joining parts; the error may be linear, angular or both.OMEGA BEND: A bend whose shape resembles the Greek letter omega and is used to accom
33、modate contraction or expansion in a duct system.PRESSURE: A force distributed over a unit area.PRESSURE, ATMOSPHERIC: The force per unit area caused by the weight of the atmosphere.PRESSURE, BURST: Maximum internal pressure above ambient which duct must withstand without rupture.PRESSURE, DESIGN: T
34、he selected normal operating pressure.PRESSURE, DIFFERENTIAL: The difference between the internal pressure at a point in a duct and a reference pressure (ambient) or, in a flowing system, the difference in pressure between the two points due to pressure drop.PRESSURE ENVELOPE: The range of pressures
35、 to which a part is subjected in normal operation.PRESSURE, MAXIMUM OPERATING: The maximum pressure a duct will experience under all possi-ble operating conditions.PRESSURE, PROOF: The maximum test pressure a duct or duct installation must sustain without per-manent deformation.RUPTURE: A break in a
36、 duct or duct assembly.SYSTEM: A combination of ducts, duct supports, duct joints and fluid control devices which will regu-late and convey fluids from a source to a point or points of use.TEMPERATURE, AUTOGENOUS IGNITION: That temperature at or above which a self-sustaining combustion of a critical
37、 volume of fluid will take place without the presence of an external source of ignition, such as a spark or flame.TEMPERATURE, DESIGN: The selected normal operating temperature.SAE INTERNATIONAL ARP699E 6 OF 1033. (Continued):TEMPERATURE, DIFFERENTIAL: The difference between the internal temperature
38、 in a duct and a reference temperature, or in a flowing system, the difference in temperature between two points due to temperature drop.TEMPERATURE, ENVELOPE: The range of temperatures to which a part is subjected in normal oper-ation.TEMPERATURE, MAXIMUM OPERATING: The maximum temperature a duct w
39、ill experience under all possible operating conditions.TENSION SYSTEM: A duct system wherein the fluid column or longitudinal forces due to internal pres-sure are not transmitted to the supporting structure. The fluid column loads of such a duct system are reacted by axial tension in the duct walls.
40、4. INSTALLATION CRITERIA AND LIMITATIONS:4.1 Introduction:Employment of high temperature pneumatic ducts in modern aircraft entails the consideration of several requirements which may be encountered during operation, maintenance, and installation assembly. The requirements are as follows:4.1.1 Struc
41、tural Deflections: The aircraft structure on which the duct installation is mounted will usually deflect sufficiently to require a flexible duct installation. Axial, torsional, and bending deflections must be considered. Installations which traverse a wing are usually exposed to the largest deflecti
42、ons. In magnitude, the axial deflections may be as high as 0.06 inches per foot of duct length. Torsional deflections may require 3 degree to 5 degree rotation about the duct centerline. Bending deflections (angular) may be in the range of 3 degrees to 7 degrees for a typical wing installation. Para
43、graph 4.2 indicates some methods of compensation for structural deflection.4.1.2 Thermal Expansion: Duct materials under high temperature exhibit a growth or expansion, which can be of considerable magnitude. If some means is not provided to compensate for this expansion, an axial compressive force
44、tending to cause failure of the ducts or supports will be developed. Duct connections to the engine should consider engine growth radially and axially due to dimensional increases caused by high temperatures. The motion envelope of the engine for normal operation and under airplane design limit load
45、 factors relative to its fuselage or nacelle structure should be established and considered. The difference in length due to contraction of the airframe at low temperature and expansion of the duct at high temperature usually results in the largest relative duct motion. Paragraph 4.2 indicates some
46、methods for compensating for thermal expansion.SAE INTERNATIONAL ARP699E 7 OF 1034.1.3 Thermal Shock: Design of the duct system should take into account the effect of thermal shock. The minimum temperature, maximum temperature, and rate of temperature rise for thermal shock should be determined by a
47、nalysis based on the expected areas of aircraft operation. Usually, the extreme condition occurs with ground operation following cold soak at the minimum design temperature.4.1.4 Space Allocation: Space allocation is another limitation in the duct installation. High priority should be given to the d
48、uct routing for the following reasons:A. Operation - A straight duct provides a minimum pressure drop.B. Installation Assembly - Sufficient space should be provided to make possible the easiest and cleanest installation assembly to provide structural deflection and thermal expansion compensation, an
49、d ease of maintenance and inspection.C. Safety - Adequate space allocation can mean proper isolation of the high temperature duct from combustibles and components sensitive to high temperature. It is recommended that high temperature ducts be located above and/or isolated from ducts transporting combustible fluids by routing the ducts as far away from each other as possible or providing separate compartments. A shutoff valve should be
