Microfluidic systems have witnessed rapid development in recent years. As one of the most common structures, the micro-orifice is always included inside microfluidic systems. Hydrodynamic cavitation in the micro-orifice has been experimentally discovered and is harmful to microfluidic systems. This paper investigates cavitating flow through a micro-orifice. A rectangular micro-orifice with a l/d ratio varying from 0.25 to 4 was selected and the pressure difference between the inlet and outlet varied from 50 to 300 kPa. Results show that cavitation intensity increased with an increase in pressure difference. Decreasing exit pressure led to a decrease in cavitation number and cavitation could be prevented by increasing the exit pressure. In addition, the vapor cavity also increased with an increase in pressure difference and l/d ratio. Results also show the pressure ratio at cavitation inception was 1.8 when l/d was above 0.5 and the cavitation number almost remained constant when l/d was larger than 2. Moreover, there was an apparent difference in cavitation number depending on whether l/d was larger than 1.

https://www.mdpi.com/2072-666X/10/3/191/pdf

Cavitating Flow through a Micro-Orifice

Adjustment method and energy consumption of centrifugal pump based on intelligent optimization algorithm

To determine the effect of rotor eccentricity on the vibration of multistage pumps, a five-stage centrifugal pump with vaned diffusers was selected to experimentally measure the vibration character...

https://journals.sagepub.com/doi/pdf/10.1177/1461348419854610

Influence of rotor eccentricity on vibration characteristics in a five-stage centrifugal pump with vaned diffusers:

Experiments on Pressure Distribution of a Low Specific-Speed Centrifugal Pump with Atypical Open Impeller

Large-scale vaned-voluted centrifugal pump is a key component in water conveyance engineering. Hydraulic performance and pressure pulsation are important assessment indicators for operation efficiency and stability. During the common operation, the impeller eccentricity is easy to occur due to installation error, radial force and other reasons, which results the changes of hydraulic performance and pressure pulsation. In this study, the hydraulic performance and pressure pulsation in the vaneless region are analyzed by computational fluid dynamics method. The influence of eccentric impeller on the hydraulic performance in each components and the pressure pulsation is studied. Results show that the eccentric impeller causes the increasing of hydraulic dissipation especially in the volute. However, decreasing of the hydraulic dissipation happens in the draft tube. Impeller eccentricity significantly enhances the amplitude of rotation frequency, but has no obvious effect on the blade passing frequency and its harmonics. The peak-peak value of pressure pulsation of eccentric impeller increases rapidly with the eccentricity ratio. The results of this study provide scientific support for solving the stability problem caused by eccentric impeller in engineering cases.

Chengbin Wang

Papers

Experimental Measurement of Cavitation-Induced Vibration Characteristics in a Multi-Stage Centrifugal Pump

Influence of rotor eccentricity on vibration characteristics in a five-stage centrifugal pump with vaned diffusers: