Utility of CFD in the design and performance analysis of hydraulic turbines - A review

Design and performance analysis of hydraulic turbines are two very crucial aspects of any hydro power project which ensure economical and efficient functioning of these plants. In this context, numerical hydrodynamic analysis of water turbines has been bringing revolutionary changes in the process since the last decade. In the recent years, advancements in computational resources have made the job quite easier and more reliable but brought new challenges as well. Appropriate use of various models and numerical solution schemes in order to capture different hydrodynamic phenomena is highly debatable, even today, due to the lack of generality and robustness. This paper illustrates various utilities of computational fluid dynamics (CFD) in simulating hydraulic turbine operations. The work is mainly aimed at critically reviewing various computational methodologies for achieving different objectives of hydraulic design and performance evaluation of water turbines. Regarding this, different objectives of computational investigations of hydraulic turbines such as derivation of performance characteristics, analysis of various unsteady phenomena, prediction and analysis of cavitation and determination of various losses are discussed in detail. A discussion on boundary conditions and turbulence modeling for capturing different hydrodynamic phenomena at design and off-design operations of hydraulic turbines is one of the major scopes of the paper. Also, various optimization techniques in combination with CFD for hydraulic performance optimization of the turbines are briefly discussed. This work is a dedicated attempt to bring various aspects of computational hydrodynamic investigation of hydraulic turbines on a single platform. Having done the extensive literature review of the CFD utilities for the turbines along with disseminating the best practices, certain research gaps and loose ends are identified and given as future scopes which are also the major highlights of the work. (C) 2020 Published by Elsevier Ltd.