Hello. Sign In
Standards Store

SAE AIR1168/1

1990 Edition, March 31, 1990

Complete Document

Thermodynamics of Incompressible and Compressible Fluid Flow

Includes all amendments and changes through Reaffirmation Notice , June 2011

Detail Summary

Active, Most Current

Price (USD)
Single User
In Stock
Add to Cart

People Also Bought These:

ASME B18.16.6

Product Details:

  • Revision: 1990 Edition, March 31, 1990
  • Published Date: June 2011
  • Status: Active, Most Current
  • Document Language: English
  • Published By: SAE International (SAE)
  • Page Count: 156
  • ANSI Approved: No
  • DoD Adopted: No

Description / Abstract:

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 gas is incompressible introduces an error of a magnitude that is dependent on the fluid velocity and on the 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. At higher velocities and for large loss coefficients (Kt and 4fL/D), compressible flow analysis should be used.
AIA/NAS Aerospace Standards