Practical Measurement of The Burning Rate of Solid Propellant (Polyester) Using Crawford's Method

Abstract

 With the Crawford Strand Burner method of burn rate measurement, a small sample of propellant is burned in a closed cylinder firing vessel at a certain constant (or approximately constant) pressure. Each propellant sample is electrically ignited at one end, and the duration for the strand to burn along is measured. The strands are usually completely insulated to ensure that burning only occurs vertically on the surface. Various means are used to measure the duration. the paper depends on the method of changing the pressure. the burning rate depended on the length of the sample and the burning duration. Nitrogen is used to pressurize the firing vessel. To effectively characterize the burn rate in relation to pressure relationship for a particular propellant, 10 or more tests may be performed at pressures ranging from 20 bars to 100 bars or more.