Research on the modeling and simulation of reaction thrust characteristics of water jet

This paper is to investigate the effects of nozzle geometry on reaction thrust characteristics under various nozzle dimensions, inlet and outlet conditions. The reaction thrust formula is deduced based on the elementary momentum theory through the theoretical analysis. CFD simulations are conducted to acquire the pressure and velocity distributions on the outlet cross-section of nozzles. The pressure and velocity distributions are substituted into the reaction thrust formula and therefore the computational results of reaction thrust are calculated. The results indicate that the water jets issuing from the streamline nozzle produce considerably lager reaction thrust compared to the other two geometries. The reaction thrust reaches the maximum when the aspect ratio (length to diameter ratio) l/d=1. Under the same flowrate and aspect ratio, the bigger the diameter, the smaller the reaction thrust. The reaction thrust shows linear and quadratic growth with increasing inlet pressure and flowrate, respectively. The outlet pressure has little effect on reaction thrust.