Investigation effect of the expansion ratio and propellant specifications on performance parameters of a nozzle and validation using experimental test

In this paper, the effect of variation in the expansion ratio of the convergent-divergent nozzle on the performance parameters such as specific impulse, nozzle output velocity and output temperature is investigated using thermodynamic relations for different propellant. Then, three nozzles with different expansion ratios are manufactured and their thrust force with three different propellants is measured using experimental tests. The results show that with increasing the area expansion ratio, specific impulse, nozzle output velocity, output Mach number and thrust coefficient increase nonlinearly and the nozzle output temperature decreases. In addition, it is observed that with increasing the specific heat ratio of propellants, the output Mach number increases and the thrust coefficient and output temperature decrease. Also, with increasing the specific heat ratio and increasing the specific constant of the gases, the specific impulse and the nozzle output velocity increase. Furthermore, the thrust force increases with increasing nozzle expansion ratio and decreases with increasing propellant heat ratio. Finally, by comparing the thrust force obtained from the thermodynamic relations and their counterpart measured thrust force, the accuracy of the calculations is confirmed