Downloaded from https://www.everyspec.com MIL-STD-1311D METHOD 1155 COOLANT-PRESSURE DROP VERSUS COOLANT FLOW (Forced air or fluid-cooled types) 1. General. When applicable, the following conditions shall be specified on the TSS for each separate cooling system: a. Coolant type(s), flow (volume and velocity), direction of flow, area and method of application, limits of incoming temperature, system pressure (if other than atmospheric). b. Appropriate meters, indicators, and methods of measurement. c. Accessories such as air socket or distributor, water (or fluid) jacket, auxiliary radiators (terminals, etc.), and air directors or reflectors.
When relevant, manufacturer's part number, catalog number, etc., for commercially available components shall be specified or complete detailed drawings shown. 2. Procedure. a. With conditions as specified on TSS (conditions shall include exceptional conditions or environmental requirements such as closed systems, altitude, inert gases, etc.), the pressure drop(s) shall be within limit(s) specified. Pressure measurement shall be made as close to the TUT as possible. b. Formula: P = P inlet - P outlet Fluid systems: P is the gauge/pressure in pounds/square inch (psi). Forced-air systems: P is the static-head pressure in inches of water (W.G.). METHOD 1155 1155-1 19 April 1968