A Consolidated Model for the Turbine Operation of Centrifugal Pumps

A consolidated model for the turbine operation of centrifugal pumps comprising accurate prediction, optimum selection, and rigorous evaluation has been the primary need and the most challenging tasks for the industry to deal with. This paper introduces a consolidated model that is developed from experimental results of different pump shapes (20–80 rpm) and turbomachine fundamentals directly resulting in the parsimony feature of the model. The model also creates a new basis for dealing with uncertainties. The prediction model segment of the consolidated model requires only the pump shape and size as input parameters for bringing out the complete turbine characteristics. The selection model segment, on the other hand, requires the site head and flow as fixed input parameters and turbine speed as the control parameter to prescribe suitable pumps available in the market. The evaluation model segment compares the absolute turbine characteristics of the suitable pumps and recommends the most suitable pump for the given site. The model also includes an acceptance criterion that relates the deviation of the “pump as turbine” operating parameters with the site parameters, and it is very useful at the evaluation stage. The features of the consolidated model are illustrated with two case studies, which highlight the importance of evaluation in addition to the prediction and basic selection of pumps operating as turbines. In order to increase the accuracy and robustness of the model, the paper recommends an optimization routine stage on the existing model that comprises results of more pump shapes (obtained through field projects or extended laboratory work). The optimization procedure suggested would come a long way to provide a lasting solution for the search of a reliable pump as turbine model.