Effect of Groove Sectional Shape on the Lubrication Characteristics of Hydraulic Spool Valve

Abstract

The spools in most all the hydraulic spool type control valve have several circumferential grooves to prevent well known hydraulic locking problems which result in high friction force and excessive wear. In this paper, a commercial computational fluid dynamics (CFD) code, FLUENT is used to investigate the effects of groove sectional shapes and its sizes on the flow and lubrication characteristics of single grooved hydraulic spool valve. The streamlines, velocity and pressure distributions in the groove, and leakage flow through the clearance are obtained for various groove depths and sectional shapes. For shallow groove, the streamlines and leakages are highly affected by groove shapes and depths. However, for relatively deep groove, the pressure distribution and leakage are nearly uninfluenced by groove depth. It is newly found that there occurred vortices inside groove beyond a certain ratio of groove depth to width. The vortex can play as contaminants collector so contribute to reduce abrasive wear. The numerical method adopted in this paper and results can be used in optimum design of spool valves.

Optimization Algorithm and Joint Simulation to Micro Thermal Deformation Using Temperature Measurement in the Orifice of Hydraulic Valve

“…The hydraulic pumping station (1) provided oil for the experiment. The oil filter (3), throttle valve (4), inlet pressure gauge (5) and inlet thermometer (6) (used to test the inlet temperature of CH10) are integrated into the inlet integration block (8). The outlet pressure (9) gauge and outlet thermometer (10) (used to test the device outlet temperature of CH11) are integrated into the outlet integration block.…”

“…The size of a clearance should be set with regard to the following: the clearance should be small enough to prevent internal leakage, yet big enough to provide the sufficient space needed to ensure smooth action [6,7]. Barriers to achieving ideal clearance include factors such as roughness variation [8][9][10][11], particle pollution [12][13][14][15][16][17] and thermal deformation of valve orifices. Thermal deformation occurs when viscous heating generated by fluids increases the temperature of the valve orifice.…”