Design and Development of Guide Vane Cascade Test Rig

Abstract Flow instabilities around guide vanes of the Francis turbine directly contribute to the pressure pulsation, which is caused by rotor-stator interaction at the inlet of the runner. An experimental guide vane cascade rig is being developed at the Indian Institute of Technology Roorkee, whose flow field is set up to match the actual turbine’s. The test rig is designed for a maximum discharge of 0.06 m3/s in the closed loop, and provisions are made for particle image velocimetry to investigate the flow field around the clear plexi guide vane. Periodic walls of the flow channel between guide vanes are identified as the starting profile for the boundary of the cascade. The cascade will be made of a transparent acrylic sheet with a PIV window size of 230 mm X 59 mm to use a laser system. A 6 mm diameter pressure sensor measures pressure at the suction and non-suction sides of the guide vane. This paper presents the design and arrangements of the test rig components according to the discharge condition. Scale-down design calculations for the turbine are done using IEC 60193. The numerical model of guide vane cascade is prepared using ANSYS CFX. The numerical flow field investigation of the cascade is carried out to find the pressure and velocity distribution at the mid-span location and around the pressure and suction side of the guide vane at best efficiency point. The cascade’s inlet and outlet flow conduits have been optimized through computational fluid dynamics to check the pressure drop across the cascade and match the flow field to the actual turbine. Based on CFD results, the final layout of the test setup will be designed and manufactured.