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Thermodynamics of Incompressible and Compressible Fluid Flow

2019-04-11
CURRENT
AIR1168/1A
The fluid flow treated in this section is isothermal, subsonic, and incompressible. The effects of heat addition, work on the fluid, variation in sonic velocity, and changes in elevation are neglected. An incompressible fluid is one in which a change in pressure causes no resulting change in fluid density. The assumption that liquids are incompressible introduces no appreciable error in calculations, but the assumption that a gas is incompressible introduces an error of a magnitude that is dependent on the fluid velocity and on the loss coefficient of the particular duct section or piece of equipment. Fig. 1A-1 shows the error in pressure drop resulting from assuming that air is incompressible. With reasonably small loss coefficients and the accuracy that is usually required in most calculations, compressible fluids may be treated as incompressible for velocities less than Mach 0.2.
Standard

Thermodynamics of Incompressible and Compressible Fluid Flow

2011-06-20
HISTORICAL
AIR1168/1
The fluid flow treated in this section is isothermal, subsonic, and incompressible. The effects of heat addition, work on the fluid, variation in sonic velocity, and changes in elevation are neglected. An incompressible fluid is one in which a change in pressure causes no resulting change in fluid density. The assumption that liquids are incompressible introduces no appreciable error in calculations, but the assumption that a gas is incompressible introduces an error of a magnitude that is dependent on the fluid velocity and on the loss coefficient of the particular duct section or piece of equipment. Fig. 1A-1 shows the error in pressure drop resulting from assuming that air is incompressible. With reasonably small loss coefficients and the accuracy that is usually required in most calculations, compressible fluids may be treated as incompressible for velocities less than Mach 0.2.
Standard

The Advanced Environmental Control System (AECS) Computer Program for Steady State Analysis and Preliminary System Sizing

2003-10-31
HISTORICAL
AIR1706B
Many different computer programs have been developed to determine performance capabilities of aircraft environmental control systems, and to calculate size and weight tradeoffs during preliminary design. Many of these computer programs are limited in scope to a particular arrangement of components for a specific application. General techniques, providing flexibility to handle varied types of ECS configurations and different requirements (i.e., during conceptual or preliminary design, development, testing, production, and operation) are designated “company proprietary” and are not available for industry-wide use. This document describes capabilities, limitations, and potentials of a particular computer program which provides a general ECS analysis capability, and is available for use in industry. This program, names AECS1, was developed under the sponsorship of the U.S. Air Force Flight Dynamics Laboratory (References 1 and 2).
Standard

THE ADVANCED ENVIRONMENTAL CONTROL SYSTEM (AECS) COMPUTER PROGRAM FOR STEADY STATE ANALYSIS AND PRELIMINARY SYSTEM SIZING

1986-10-01
HISTORICAL
AIR1706A
Many different computer programs have been developed to determine performance capabilities of aircraft environmental control systems, and to calculate size and weight tradeoffs during preliminary design. Many of these computer programs are limited in scope to a particular arrangement of components for a specific application. General techniques, providing flexibility to handle varied types of ECS configurations and different requirements (i.e., during conceptual or preliminary design, development, testing, production, and operation) are designated "company proprietary" and are not available for industry-wide use. This document describes capabilities, limitations, and potentials of a particular computer program which provides a general ECS analysis capability, and is available for use in industry. This program, names AECS1, was developed under the sponsorship of the U.S. Air Force Flight Dynamics Laboratory (References 1 and 2).
Standard

TESTING OF PROTOTYPE AIRPLANE AIR CONDITIONING SYSTEMS

1960-03-01
HISTORICAL
ARP217A
These recommendations are written to cover the testing of air conditioning equipment functioning as a complete and installed system in prototype civil aircraft for the purpose of: A Demonstrating the safety of the installation and equipment. B Demonstrating performance of the installation and equipment. a Source of heat b Source of fresh air and/or ventilation c The cooling system d Distribution system including ducting, joints, etc. e Water separator f Exhaust system g Temperature control system. h Cabin pressurisation system including flow and pressure controls. C Obtaining data for future design and to aid in the analysis of in-service performance of the systems and equipment.
Standard

TEMPERATURE CONTROL EQUIPMENT, AUTOMATIC, AIRPLANE CABIN

1956-03-15
HISTORICAL
ARP89B
This recommended practice covers automatic cabin temperature control systems of the following types for pressurized and unpressurized cabins: Type I - Proportioning. Type II - On-Off, or Cycling. Type III - Floating, including modifications thereof.
Standard

TEMPERATURE CONTROL EQUIPMENT, AUTOMATIC, AIRCRAFT COMPARTMENT

1992-03-01
HISTORICAL
ARP89C
The recommendations of this ARP are primarily intended to be applicable to temperature control of compartments, occupied or unoccupied, of civil aircraft whose prime function is the transporting of passengers or cargo. The recommendations will apply, however, to a much broader category of civil and military aircraft where automatic temperature control systems are applicable.
Standard

TEMPERATURE CONTROL EQUIPMENT, AUTOMATIC AIRPLANE CABIN

1943-01-01
HISTORICAL
ARP89
These specifications are written to cover automatic temperature controls under three classifications, namely: A AUTOMATIC TEMPERATURE CONTROLS - GENERAL - Dealing with features applicable to all types and uses. B AUTOMATIC TEMPERATURE CONTROLS - MILITARY AND COMMERCIAL - Covering features applicable to military aircraft and commercial aircraft. C DESIRABLE DESIGN FEATURES - General information for use of those concerned in meeting the requirements contained herein.
Standard

Spacecraft Life Support Systems

2011-06-20
HISTORICAL
AIR1168/14
A life support system (LSS) is usually defined as a system that provides elements necessary for maintaining human life and health in the state required for performing a prescribed mission. The LSS, depending upon specific design requirements, will provide pressure, temperature, and composition of local atmosphere, food, and water. It may or may not collect, dispose, or reprocess wastes such as carbon dioxide, water vapor, urine, and feces. It can be seen from the preceding definition that LSS requirements may differ widely, depending on the mission specified, such as operation in Earth orbit or lunar mission. In all cases the time of operation is an important design factor. An LSS is sometimes briefly defined as a system providing atmospheric control and water, waste, and thermal management.
Standard

Spacecraft Boost and Entry Heat Transfer

2008-02-19
HISTORICAL
AIR1168/11
The prediction of vehicle temperatures during ascent through the earth’s atmosphere requires an accurate knowledge of the aerodynamic heating rates occurring at the vehicle surface. Flight parameters required in heating calculations include the local airstream velocity, pressure, and temperature at the boundary layer edge for the vehicle location in question. In addition, thermodynamic and transport air properties are required at these conditions. Both laminar and turbulent boundary layers occur during the boost trajectory. Experience has shown that laminar and turbulent heating are of equivalent importance. Laminar heating predominates in importance in the stagnation areas, but the large afterbody surfaces are most strongly affected by turbulent heating. Once the local flow conditions and corresponding air properties have been obtained, the convective heating rate may be calculated for a particular wall temperature.
Standard

Spacecraft Boost and Entry Heat Transfer

2011-07-25
CURRENT
AIR1168/11A
The prediction of vehicle temperatures during ascent through the earth’s atmosphere requires an accurate knowledge of the aerodynamic heating rates occurring at the vehicle surface. Flight parameters required in heating calculations include the local airstream velocity, pressure, and temperature at the boundary layer edge for the vehicle location in question. In addition, thermodynamic and transport air properties are required at these conditions. Both laminar and turbulent boundary layers occur during the boost trajectory. Experience has shown that laminar and turbulent heating are of equivalent importance. Laminar heating predominates in importance in the stagnation areas, but the large afterbody surfaces are most strongly affected by turbulent heating. Once the local flow conditions and corresponding air properties have been obtained, the convective heating rate may be calculated for a particular wall temperature.
Standard

OZONE PROBLEMS IN HIGH ALTITUDE AIRCRAFT

1996-07-01
HISTORICAL
AIR910A
The purpose of this report is to provide information on ozone and its control in high altitude aircraft environmental systems. Sources of this information are listed in the selected bibliography appearing at the end of this report, to which references are made throughout.
Standard

NBC Protection Considerations for ECS Design

2014-07-01
CURRENT
AIR4362A
This SAE Aerospace Information Report (AIR) provides Nuclear, Biological and Chemical (NBC) protection considerations for environmental control system (ECS) design. It is intended to familiarize the ECS designer with the subject in order to know what information will be required to do an ECS design where NBC protection is a requirement. This is not intended to be a thorough discussion of NBC protection. Such a document would be large and would be classified. Topics of NBC protection that are more pertinent to the ECS designer are discussed in more detail. Those of peripheral interest, but of which the ECS designer should be aware are briefly discussed. Only radiological aspects of nuclear blast are discussed. The term CBR (Chemical, Biological, and Radiological) has been used to contrast with NBC to indicate that only the radiological aspects of a nuclear blast are being discussed.
Standard

Liquid Cooling Systems

2016-09-10
WIP
AIR1811B
The purpose of this Aerospace Information Report (AIR) is to provide guidelines for the selection and design of airborne liquid cooling systems. This publication is applicable to liquid cooling systems of the closed loop type and the expendable coolant type in which the primary function is transporting of heat from its source to a heat sink. Most liquid cooling system applications are oriented toward the cooling of electronics. Liquid cooling techniques, heat sinks, design features, selection of coolants, corrosion control, and servicing requirements for these systems are presented. Information on vapor compression refrigeration systems, which are a type of cooling system, is found in Reference 1.
Standard

High Temperature Pneumatic Duct Systems for Aircraft

2022-03-21
WIP
ARP699F
This Recommended Practice is intended to outline the design, installation, testing, and 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 industry.
Standard

High Temperature Pneumatic Duct Systems for Aircraft

2015-11-09
CURRENT
ARP699E
This Recommended Practice is intended to outline the design, installation, testing, and 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 industry.
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