Investigation On Viscous Heating And Spool Deformation Of Throttle Valve

The thesis presents a numerical analysis of the viscous heating and spool deformation of throttle valves. The CFD method is used to simulate the temperature distribution around the notch of the throttle valve, due to the viscous heating effect caused by high speed flow of large-viscosity hydraulic oil. Basing on the CFD result, the FEA method is used to simulate the spool deformation of the throttle valve due to the high local temperature, which is supposed to be the causation of the jam fault.Temperature distributions of U-shape and V-shape throttle valves are simulated. The influence of three factors on the temperature distributions are investigated, including the U-shape notch structure parameters, the pressure drop and the notch type. Several conclusions are obtained: with the depth of the U-shape notch increasing, the increasing rate of the maximum temperature to the fluxes is decreased; and there is a linear relation between the maximum temperature and the inlet-outlet pressure drop; the high local temperature of U-shape throttle valve appears near the contour lines of the notch, while that of V-shape throttle valve occurs on the bottom face of the notch.In order to study the spool deformation, the heat transfer and thermal stress on the spool of U-shape throttle valve are simulated. It is observed that the peak radial deformation of the U-shape notch spools of small radii are occurred in both side walls of the notch, and that of big depth are occurred in the semicircle wall. In the former situation, the increasing rate of the maximum radial spool deformation to the fluxes is decresed.The thesis provides a deep insight into the jam fault problems. These conclusions presented above are important for improving the design of throttle valves to get rid of the jam fault. The experience of application of the coupling CFD and FEA provides a reference for the research of the heat transfer and deformation.