Experimental investigations concerning cavitation in radial flow pump for three different leading edge profiles of the vane were carried out in an open circuit system. The operating condition of the radial flow pump under cavitating case was understood by measurement of noise and vibration along with the pump parameters for various speeds and flow rates. The outcome of the experimental results revealed that the noise and vibration were better predictors of inception and development of cavitation. Further observation inferred from critical net positive suction head (NPSH) curve of 3% head drop and critical NPSH value of noise and vibration are presented.

For a pump, the inlet condition of flow determines the outlet conditions of fluid (i.e., energy). As a rule to minimize the losses at the entry of pump, the bends should be avoided as one of the methods. But for the case of vertical inline pump, it is unavoidable in order to save the space for installation. For the purpose of investigation in inlet pipe of vertical inline pump, the unsteady Reynolds-averaged Navier–Stokes equations are solved using the computational fluid dynamics (CFD) code. The results have been shown that there is a good agreement between the performance characteristics obtained from the simulation and experiments. The velocity coefficient from the simulation along the inlet pipe sections is well matched with the theoretical values and found to have variation near the exit of inlet pipe. The pressure and velocity coefficients studies depict the flow physics at each section along with the study of helicity at the exit of inlet pipe to determine the recirculation effects. It is observed that the vortices associated with the motion of the particles are moved toward the surfaces and are more intense than the mean flow. The trends of pressure coefficient at the exit of inlet pipe were addressed with reference to the various flow rates for eight set of radial lines. Hence, this work concludes that for inlet pipe, the generation of circulation was due to the stream path and the reverse flow from the impeller and was reconfirmed with the literature.

As an indispensable equipment in thermal power plants, the high-power coolant pump is necessary for high hydraulic performance with good structural safety for transferring of heat produced by fuels. However, the design of blade thickness for coolant pump especially at the off-design condition is still empirical and arbitrary. In the present work, the hydraulic performance, internal flow pattern, and structural response arising from the variations of blade thickness in coolant pump have been investigated using computational fluid dynamics and fluid–structure interaction methods. The numerical results have been verified by experimental performance and found to be good. To improve the accuracy of head calculation at the overload condition, a modified equation is proposed with the help of multi-island genetic algorithm and the average deviation is reduced from 58.50 to 1.59%. With the blade thickening process, the hydraulic performance is gradually deteriorated especially at the overload condition, and the flow behavior is changed with the proportion of high velocity near the pressure surface enlarging, the proportion of low velocity near the suction surface decreasing, and the pressure fluctuation intensity rising. Besides, increasing the blade thickness beyond 23.0 mm, the stress reduction is not effective. However, it helps to increase the natural frequency for suppressing the resonance. Finally, considering the optimal hydraulic and structural performances, the blade thickness is optimized to 23.0 mm.