Rapid Computations to Match Impellers With Inducers

Simplifying assumption are examined to quicken the fluid dynamic design of centrifugal pump impellers when an upstream inducer is applied. First a complete inducer with a complete impeller is computed. Second a more rapid calculation method is investigated which utilizes only one inducer passage and one impeller passage. Pitchwise averaging is performed at their interface. A third and even more rapid approach replaces the entire inducer with simulated velocity and pressure boundary conditions upstream of a single impeller passage. In all 3 computed cases a vaned channel diffuser is included at the impeller outlet. The 3 computed cases are compared to the measured pump pressure and efficiency characteristic. In terms of computational intensity the complete calculation presented here took 5 days to generate a 9 point characteristic curve. For the same number of points the averaged case took 2.5 days while the simulated case took 1.5 days to compute. In terms of the results the 3^rd simulated method is reasonable until the final centrifugal impeller design phase is reached, when more accurate calculations are required.