性能預測的關鍵是對泵內各種損失的計算。臥式離心泵內的水利損失主要是葉輪和蝸殼內的損失。性能預測采用的方法可歸納為兩種：
損失模型法。通過對各部分水力損失的物理本質及其影響因素的分析，尋求水力損失與結構參數的關系，對流場作一定的假設、簡化，建立水力損失的計算模型。該方法的優(yōu)點是可以全面考慮諸如二次流、進口回流、邊界層分離、漩渦和尾跡等各種因素的影響，對實際的性能預測有很高的實用性和準確性。
數值方法，又稱為數值試驗或計算試驗法。目前純數值方法主要是基于計算流體力學對泵內流場進行數值模擬，得到泵內流場信息，進而計算出臥式離心泵的揚程、功率、效率和流量之間的關系，實現對臥式離心泵性能的預測(圖\文www.www.monolithcanada.com/)。
中譯英：
Performance prediction is the key to pump a variety of loss calculation. Horizontal centrifugal pump water loss is the loss of impeller and volute. Performance prediction methods can be classified into two:
Loss model method. Based on the physical nature of each part hydraulic loss and analysis of its influence factors, seek hydraulic loss and the relationship between the structural parameters of flow field, make certain assumptions, a simplified, establishing the hydraulic loss calculation model. The advantage of this method is that can be considered in a comprehensive way such as two flow, inlet reverse flow, boundary layer separation, vortex and wake and the influence of various factors, the actual performance prediction is of high practicability and accuracy.
Numerical method, also known as the numerical experimental or computational experimental method. The pure numerical method is mainly based on the computational fluid dynamics numerical simulation of the flow field inside the pump, get the pump flow information, then to calculate the horizontal centrifugal pump head, power, efficiency and the relation between flow, realize the horizontal centrifugal pump performance prediction.