Application of entropy production theory for energy losses and other investigation in pumps and turbines: A review

As the demand for energy consumption saving and emission reduction become an urgent need in the contemporary world, the requirements for pumps and turbines need to pay more attention, by placing more emphasis on advanced technical methods and theoretical models to improve their energy efficiency. One of these methods is the entropy production theory, which may introduce the possibility of improving the performance of the rotating machine by appropriate modelling of flow phenomena occurring to reduce the entropy production and energy dissipation. Compared to the traditional methods of analysing the hydraulic losses, the entropy production process description accurately highlights and predicts the area distribution of the power loss, assessing the pressure drop and computing a detailed distribution of hydraulic losses in the pump components. It also provides accurate and intuitive reference information for researchers and subsequent improvement. Recently, the importance of this method is getting increased in the research area of investigating the internal flow mechanism and optimizing the pump's design. In this paper, the entropy production in pump flow have been reviewed, including energy loss analysis, design optimization, cavitation analysis, and fault diagnosis. Different perspectives were presented for future works and introduction to other methods such as kinetic energy dissipation theory to obtain procedures that reveal energy loss to improve the pump performance and try to understand the causes of pump failure. This review provides theoretical guidance for optimal design and assessment of the operational condition in terms of irreversible flow losses in the pumps.