Simulation and Experimental Study on Thermal Characteristics of Linear Conjugate Internal Gear Pumps

This study presents a systematic investigation on the thermal power characteristics of linear conjugate internal gear pumps. Through analyzing the heat sources of each friction pair in the internal gear pump, mathematical heat generation models for key friction pairs are derived based on mechanical efficiency and volumetric efficiency. Furthermore, the simulation model of the gear pump was established, and the losses of the internal gear pump under different working conditions were calculated and analyzed. The variation patterns of mechanical efficiency and volumetric efficiency under different pressures and speeds are studied, revealing significant declines in both efficiencies under complex operating conditions, with inefficiencies primarily occurring under low-speed high-pressure and high-speed low-pressure scenarios. The results show that the deviation between the simulation results of mechanical efficiency and the experimental value is less than 1.6%, and the deviation between the simulation results of volumetric efficiency and the experimental value is less than 1%. Variations in speed and pressure significantly impact both mechanical and volumetric efficiencies, with notable efficiency drops observed under low-speed/high-pressure conditions. In high-pressure environments, intensified radial unbalanced forces lead to increased frictional heat generation.