Swirling flow in a conical diffuser generated with rotor-stator interaction

Application Area 6: Turbomachinery Internal Flow

Application Challenge AC6-14

Abstract

The flow unsteadiness generated in a swirl apparatus is investigated experimentally and numerically. The swirl apparatus, shown in figure below, is designed and measured in Timi\c{s}oara, Romania. The LDA measurements are performed along three survey axes in the test section to provide the characteristics of the swirling flow in the conical diffuser. The swirling flow configuration corresponds to part load operation of a Francis turbine. A series of numerical simulations is undertaken to study a highly swirling turbulent flow generated by rotor-stator interaction in a swirl generator. The purpose is to assess the applicability of different turbulence models in swirling flow with a high level of unsteadiness and a significant production and dissipation of turbulence in the flow away from the wall. Nine turbulence models are compared: four high-Reynolds number URANS, two low-Reynolds number URANS and three hybrid URANS-LES models.