No abstract

No abstract

No abstract

No abstract

The hydraulic design optimization and performance analysis of a mixed-flow pump for marine waterjet propulsion has been carried out using mean streamline analysis and three-dimensional computational fluid dynamics (CFD) code. In the present study, conceptual design optimization has been formulated with a nonlinear objective function to minimize fluid dynamic losses and then a commercial CFD code was incorporated to allow for detailed flow dynamic phenomena in the pump system. The newly designed mixedflow model pump has been tested in the laboratory. Predicted performance curves by the CFD code agree fairly well with experimental data for a newly designed mixed-flow pump over the normal operating conditions. The design and prediction methods presented herein can be used efficiently as a unified hydraulic design process of mixed-flow pumps for marine waterjet propulsion. NOTATIONb width D in diameter of the inlet duct D s nondimensional specific diameter ¼ D 2t (gH) 0:25 = ffiffiffi ffi Q p D 2t impeller diameter at the exit tip Diff LE diffuser leading edge Diff TE diffuser trailing edge g gravitational acceleration H total head (m) Imp LE impeller leading edge Imp TE impeller trailing edge N s nondimensional specific speed ¼ o ffiffiffi ffi Q p =(gH) 0:75 PS pressure surface p atm atmospheric pressure P in input shaft power (W) p s static pressure Q volume flow (m 3 /s) SS suction surface U 2t impeller speed at the exit tip V absolute velocity W relative velocity Z number of bladesimpeller rotational speed (rad/s)