Investigation Of The Draft Tube Variations Against The First Stage And The Second Stage Flow Of Banki Turbine
Sirojuddin, Lukman Kusuma Wardhana and Ahmad Kholil

Mechanical Engineering, State University of Jakarta, Indonesia

Abstract

Cross Flow Turbine usually for micro hydro-electrical power plant application especially for the isolated area. Increasing power efficiency still the most interesting topic for researches. There were many methods to increase power efficiency, one of them was to control the inflow of water from the first stage to the second stage of banki blades to be a good flow trajectory and did not strike the shaft using a draft tube. This research aimed to investigate the draft tube length variations against the flow from the first stage to the second stage of Banki turbine, so that good flow trajectory, uniform color velocity contour and not struck the shaft could be obtained. There were 2 variants runner casing and 3 variants length of draft tube, 140 mm, 240 mm, and 340 mm. 2D and 3D geometry were drawn in CAD software, while Flow Simulation test using Solidwork Flow Simulation with a discharge of water 2m^3/min and head 5.5 m. From simulation results, shown the second variant C2-2 with a length of draft tube L = 1,2 D1 = 240 mm was the best flow trajectory from the first stage to the second stage of the blade, good velocity contour and did not strike the shaft. All of those results were expected to increase the power efficiency of the turbine.

Keywords: Draft tube; Flow trajectory; Investigation; Power efficiency; Velocity contour

Topic: Mechanical Engineering