Off-design performance prediction of centrifugal pumps by using TEIS model and two-zone model

In this study, an off-design performance prediction program for centrifugal pumps is developed. To estimate the losses in an impeller flow passage, two-zone model and Two-Element In Series(TEIS) model are used. At impeller exit, the mixing process occurs with an increase in entropy. In two-zone model, there are both primary zone and secondary zone for an isentropic core flow and an average of all non-isentropic stream tubes respectively. The level of the core flow diffusion in an impeller was calculated by using TEIS model. While internal losses in an impeller are automatically estimated by using the above models, some empirical correlations for estimating external losses, for example, disk friction loss, recirculation loss and leakage loss are used. In order to analyze the vane less diffuser flow, the momentum equations for the radial and tangential directions are used and solved together with continuity and energy equations