A Numerical Method of Free Jet from a Cross-flow Turbine Nozzle

Abstract

The nozzle of a cross-flow turbine has to give a certain circumferential velocity and an optimum angle to the flow at the nozzle exit (runner inlet). Therefore, the nozzle shape has an important influence upon the turbine performance. Its shape is asymmetric and complicated, and the exit flow from it has free boundaries. The flow from such a nozzle has not been analyzed enough until now because of complexity of its flow. In this report, the flow from a nozzle with arbitrary asymmetric curved surfaces is calculated numerically by Schwarz-Christoffel method. In order to estimate the accuracy of this method, the calculation results of the flow from a cross-flow turbine nozzle are compared with experimental ones. Furthermore, the effects of nozzle shape on the exit flow are investigated.