Thermodynamic characteristics research of a water lubricating axial piston pump

Abstract

A water lubricating axial piston pump (WLAP) is one of the key components in water hydraulic systems. However, the characteristics of water, including low viscosity, strong corrosiveness, and easy vaporization, results in the increase of friction and wear of pairs, and the increase of temperature. Compared with oil pumps, the thermodynamic characteristic of WLAP is more serious. In this paper, the integrated thermodynamic model of WLAP, which includes heat generation of pairs and heat conduction of water and air, is established to improve pump design. The calculation results show that the water temperature of WLAP exceeded 90 ℃, and the pump could not work normally in extreme conditions (the inlet water temperature and ambient temperature are both 50 ℃). Consequently, a cooling design of WLAP, which circulates the inlet water in the pump chamber, is carried out. Then, the thermodynamic model was modified. Based on this model, the temperature rise characteristics and heat dissipation characteristics of the WLAP are analyzed. The steady-state water temperature of pump shell under extreme conditions is obtained. The temperature sensors and a thermal imaging were used to measure the temperatures of the WLAP. The results indicate that the water temperature of WLAP decreases significantly. The difference of the steady-state temperature of WLAP between simulation and experiment is less than 4 ℃, and its temperature distribution is uniform. Therefore, the cooling design of WLAP is effective and it can work normally under the maximum speed and pressure in extreme conditions.