Downloaded from https://www.everyspec.com MIL-STD-81OC Required information: a. Chamber air temperature during test: 27° C (81”F) b. Fuel temperature: 24°C (75”F). c. Specific gravity of fuel at 16° C (61”F): 0.704. d. Test altitude: 20,000 feet (P = 6.75 lbs./in2). e. Air-vapor ratio (desired): 13-tO-l. Step 1 - Employing the following equation, calculate the apparent air-vapor ratio: AV (desired) = AAV = (-) 1“04 ( 14.:96 -0.04 1.04 where: AAv = Apparent air-vapor ratio AV = Desired air-vapor ratio P.
Pressure equivalent of altitude, lbs./in2 At or above 10,000 feet altitude, with chamber air temperature above 16°C (61”F) and at AV ratio of 5 or greater, air-vapor ratio = air-fuel ratio (AF) for 100/130 octane fuel. Since the conditions of the explosion test under Considerationwill always be well above these values,AV will equal AF in all cases. ! I Step 2 - Since AV = AF, use figure 511.1-1 to determine weight of air (WA) and divide by AAV to obtain uncorrected weight of fuel required (WFU), w WA & . 0.116 lbs, fuel weight FU’~= 29.68 (uncorrected). Figure S11.1-1 pertains to a specific test chamber and shall not be used for all test facilities.
It is utilized herein for illustrationof the method of employment only. Each test chamber must have its own chamber volume chart. MSTHOD 511.1 511.1-2