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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 Life Support Systems

2012-10-15
CURRENT
AIR1168/14A
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 Equipment Environmental Control

2011-07-25
CURRENT
AIR1168/13A
This part of the manual presents methods for arriving at a solution to the problem of spacecraft inflight equipment environmental control. The temperature aspect of this problem may be defined as the maintenance of a proper balance and integration of the following thermal loads: equipment-generated, personnel-generated, and transmission through external boundary. Achievement of such a thermal energy balance involves the investigation of three specific areas: 1 Establishment of design requirements. 2 Evaluation of properties of materials. 3 Development of analytical approach. The solution to the problem of vehicle and/or equipment pressurization, which is the second half of major environmental control functions, is also treated in this section. Pressurization in this case may be defined as the task associated with the storage and control of a pressurizing fluid, leakage control, and repressurization.
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

NBC Protection Considerations for ECS Design

2008-08-19
HISTORICAL
AIR4362
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.
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