Title: Numerical investigation of cavitating flow in elbow type draft tube

Authors: Pankaj P. Gohil; R.P. Saini

Addresses: Alternate Hydro Energy Centre, Indian Institute of Technology, Roorkee 247667, India ' Alternate Hydro Energy Centre, Indian Institute of Technology, Roorkee 247667, India

Abstract: Cavitation is a complex flow phenomenon which causes the damage to the hydraulic turbine components. In this paper, an attempt has been made to carry out CFD-based flow analysis of cavitation of an elbow type draft tube of hydro turbine. Under different operating conditions the performance parameters of draft tube have been analysed in ANSYS CFX using shear stress transport (SST) turbulence model and Rayleigh Plesset equation for different values of cavitation number and mass flow rate. Results are presented in the form of head loss, head recovery coefficient, efficiency, cavitation rate and distribution of the vapour volume fraction of elbow type draft tube. Based on the CFD analysis, it has been found that at low values of cavitation number the efficiency is decreased, however, other parameters such as head loss, head recovery coefficients and cavitation rates are to be increased.

Keywords: draft tube; computational fluid dynamics; CFD; efficiency; cavitation rate; head loss.

DOI: 10.1504/PCFD.2017.084345

Progress in Computational Fluid Dynamics, An International Journal, 2017 Vol.17 No.3, pp.172 - 179

Received: 14 Jul 2014
Accepted: 03 Jun 2015

Published online: 31 May 2017 *

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