Thermal balance and gap flow of high-pressure, large-scale plunger pairs

Abstract

Fitting gaps are a critical factor affecting the efficiency of high-pressure, large-scale plunger pumps. In actual work, fitting gaps change under liquid pressure and temperature rise, and the fluid flow in the annular channel changes under the fitting gap, in turn affecting the fitting gap. Therefore, on the basis of the thermo-fluid–structure interaction, a thermodynamic analysis model of plunger friction pairs is established in this work. The model considers the heat production due to plunger pair friction, frictional head loss, local head loss and heat dissipation caused by the fluid and air. Given that heat production and dissipation are greatly affected by annular channel flow, the deformation and leakage equations of the large-scale annular channel are established on the basis of pressure and temperature rise. In consideration of the gap deformation, gap flow, heat production, and heat dissipation of the plunger, a thermal balance equation is established, and the temperature rise of the plunger pair under different initial gaps is analyzed. In addition, a plunger pump experiment system is built to test the temperature rise of the plunger pair. Results show that the model can effectively predict the temperature of the plunger friction pair. The research results can provide a theoretical basis for the design of large-scale, high-pressure gap seals.