Research on energy loss mechanism and optimization method of liquid ring vacuum pump based on entropy production theory

To solve the problem of high energy consumption of liquid ring vacuum pumps and serious hydraulic losses that make it difficult to improve the efficiency of the pumps. Firstly, the mechanism of the influence of radical clearance on the energy loss of liquid ring vacuum pumps is investigated, and a directional and quantitative analysis of the energy loss in the flow field within a liquid ring vacuum is made based on the entropy production theory. Then the structural parameter control model oriented to the maximum suction capacity and minimum wall effect entropy production of the liquid ring vacuum pump is established. The results indicate that turbulent entropy production and wall entropy production dominate the energy losses of liquid ring vacuum pumps with radial clearance of 24 mm, 28 mm, 32 mm, and 36 mm. The entropy production caused by the wall effect mainly occurs at the shell of the gas compression region. The optimized liquid ring vacuum pump model achieves an increase in suction capacity of 8.74 %, an increase in isothermal compression efficiency of 3.75 %, and a reduction in wall effect entropy production of 19.7 %. •The type and spatial distribution of entropy production in liquid ring vacuum pumps are studied.•The mechanism of the effect of radial clearance on the energy loss of liquid ring vacuum pumps is revealed.•An optimization model of structural parameters with high efficiency and low energy consumption is developed.