Molten salt pump is one type of centrifugal pump, which is used for transporting high temperature molten salts in the different industries such as solar power plants and refineries. Generally, the performance curves of the pump are obtained experimentally using water as working fluid. In utilizing centrifugal pumps for transporting fluids with various viscosities, the important point is that the performance of the pumps is affected significantly by the fluid viscosity. Therefore, the performance of centrifugal pumps needs to be modified when they service high viscosity flu-ids due to increase in losses.