In aerospace fields and industrial sectors, high-speed centrifugal pumps are prevalent and in increasingly strict demand regarding characteristics such as the long life, small volume, light weight, and low noise. In this study, we present a novel high-speed centrifugal water pump with hydrodynamic bearings used to employ work fluid as lubricant. A three-dimensional numerical study of the turbulent fluid flow was carried out to predict the performance of the pump. The computational model was validated against experimental results during hydraulic tests. Additionally, the effect of the blade number on the head and efficiency of the pump was researched. The blade number of the impeller was changed from 4 to 8 and that of the stay vane was from 3 to 14. The results indicate that the blade number and the matching characteristic of the impeller and the stay vane significantly influenced the performance of the pump. The structure based on the seven-blade impeller and the six-blade stay vane had the highest efficiency (30.8%). Numerical investigations of this study may help reduce the significant cost and time of experimental work for a particular design.

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With the rapid development of information technology, researchers have paid attention to the pump-driven two-phase cooling loop technology for data centers, which imposes requirements on the efficiency and size of the pump. A fluid self-lubricating centrifugal pump with R134a refrigerant was developed to reach a higher rotation speed and oil-free system, resulting in a more diminutive size. Due to the high rotation speed and refrigerant pressure approaching saturated vapor pressure, the internal flow characteristics and cavitating characteristics are critical and complex. This paper focuses on the prototype’s head and cavitation performance based on experimental and numerical data. The experiments indicated that the head coefficient of the pump under design conditions is 0.9881, and the pump’s critical cavitation number and breakdown number are 0.551 and 0.412, respectively. The numerical results can predict the head and cavitation with deviations less than 2.6%. To study changing patterns in flow characteristics under the different operating conditions in the refrigerant centrifugal pump, the numerical model based on a modified Sauer-Schnerr cavitation model was built to analyze the distributions of pressure, temperature, relative velocity, and bubble volume across every hydraulic component and different degrees of cavitation, and proposed the influence of the thermal effect on refrigerant cavitating. The cavitating flow characteristics were obtained with the aim of providing guidance for the hydraulic design of a refrigerant centrifugal pump.

A novel centrifugal pump with axial directional inlet and outlet flow was presented. The system fluid was employed as the lubricant for the hydrodynamic bearings by which the pump can operate at the maximum speed of 8100 r/min without oil lubrication or rigid support. The performance curves related to the efficiency, head, and volume flow rate were obtained via a water cycle test rig. The efficiency at best efficiency point reached 36.14% with a volume flow rate of 4.13 m3/h and a head of 27.34 m at 7800 r/min. The maximum head reached 37.28 m, with a volume flow rate of 0.568 m3/h at 7800 r/min. The maximum volume flow rate of 6.05 m3/h was obtained with a head of 19.45 m at 8100 r/min. Then, the three-dimension computational fluid dynamics model with Reynolds-averaged Navier–Stokes equations and shear stress transport k- ω turbulence model for the pump and bearings was set up individually. The numerical results agreed well with the experimental data.