Effects of particle size and reciprocating frequency of the plunger on performance and flow characteristics of a diaphragm pump

The present study aims to reveal characteristics of the diaphragm pump applied in transporting the mixture of liquid and solid particles. The computational fluid dynamics (CFD) technique was used in combination with the six degree of freedom (SDOF) method to simulate the solid-liquid two-phase flow in the diaphragm pump. The zero-gap overlapping grid technique was employed to treat unsteady gap flows near the two valves. Effects of particle size and the reciprocating frequency of the plunger were investigated. The results indicate that solid particles pass smoothly through the diaphragm pump. When particle size increases from 2.0 mm to 3.0 mm, the solid volume fraction (SVF) in the pump chamber increases. When the reciprocating frequency of the plunger increases from 150 to 250 cycles per minute, the SVF increases and then decreases. When the reciprocating frequency of the plunger increases, the performance of the diaphragm pump declines, whereas the distribution of particles in the pump chamber is gradually uniformized due to the disturbance of the reversed flow from the pump outlet.