Flow characteristics of external gear pumps considering trapped volume

Abstract

This article investigates the volume change law of trapped fluid in the meshing process and the flow characteristics of external gear pumps under the following two cases: the pump design with and without relief groove. In this study, a mathematical modeling of gear pairs is deduced based on the meshing theory and a complete set of mathematical equations of tooth profile, and the flow rate equation is derived based on law of conservation of mass across the changing boundaries of a control volume. During the process, the function of the pump displacement is established, which is formed by two parts: tooth space volume and trapped volume. In addition, using a control volume approach, the trapped volume and flow rate characteristics of the pump under different design parameters of gears are discussed. The results show that the curve of trapped volume is similar to a parabola and the pump designed with a large number of teeth, module, and pressure angle easily obtained good flow rate characteristics under the same condition, which have a great benefit for designing the relief grooves and external gear pumps.

Experimental Hydraulic Device for the Testing of Hydraulic Pumps and Liquids

“…Increased of flow rate depending on the speed is consistent by authors [16,17]. Dobrota et al [18] evaluated the flow efficiency of the hydraulic pump at the nominal speed η = 95.73 % depending on the pressure p = 20 MPa and Michael et al [19] evaluated the flow efficiency at the nominal speed η = 95 %. These values corresponded with our results.…”

Design and Modeling of an Experimental Hydraulic Device

“…On the basis of the theoretical processing of the authors Hao et al (2016), Chrastina et al (2013) and Casoli et al (2005), it is possible to determine the coefficient of loss of liquid kQ, which affects the resulting liquid flow. Displacement gear pumps:…”

Experimentation and 2D Fluid Flow Simulation over an External Gear Pump

“…For each model, four distinct speeds of 2000 rpm, 2500 rpm, 3000 rpm, and 3500 rpm were used with three diverse output pressures of 2500 psi, 3000 psi, and 3500 psi. Xiaoru Hao et al [5] examined the volume variation law of surrounded fluid in the meshing procedure as well as the flow features of external gear pumps with and without a relief groove. The 2-D CFD analysis of a hydraulic gear pump was carried out by Hyun Kim et al [6].…”