Gasshastighet og trykk i en rakettmotors dyseutløp : beregninger og målinger

The pressure ratio, k, between the nozzle exitplane and the motorchamber, and the gas velocity at the nozzle exitplane, has been calculated. The results have been used to create propellant composition dependent expressions for these two parameters as a function of the nozzle expansion ratio. Theoretical pressure ratios, k, have been used together with experimental firing results to estimate the gas velocity at the nozzle exitplane. However, in four firings the pressure near the nozzle exitplane was measured, and the pressure ratio, k, from these measurements were compared with theoretical values. In order to conduct these measurements a new steel/molybdenum nozzle had to be constructed. The firings were performed with small scale rocket motors with radial burning grain (ca 0.3 kg). Two propellants with a slight performance difference, were used.