| Hydro-viscous drive (HVD) transmits power by using shear force of oil film, which is a new type of fluid power transmission, and has characteristics of high-efficiency and energy-saving, synchronous drive, small start impact and stepless speed regulation. HVD has tremendous potentials in a wide range of applications such as speed regulation and start in large belt conveyors, fans, and pumps. Therefore, it has great practical significance to carry out HVD technology research in our country. According to the existing problems, the following aspects are thoroughly researched in the dissertation.Variation of working oil viscosity with temperature is measured in experiment. The viscosity-temperature equation of the working oil is obtained. Based on the distribution of temperature between interfaces, the analytic solutions for pressure, dynamic load capacity, and torque transferred by oil film between friction pair with and without grooves are deduced. Compared with constant viscosity, the transmission characteristics of oil film are analyzed. The influence of temperature on oil film transmission characteristics is revealed.On the basis of heat conduction theory, a theoretical model of transient thermal stress coupling for steel disk under mixed friction stage is established. Heat flow distribution coefficient and heat flux between friction pair are determined. Combining heat flux, initial conditions and boundary conditions, the theoretical model is solved using finite element method, the distribution law of temperature field and stress field of steel disk are found. The influence of time, thickness of steel disk, and material of friction pair on temperature field and stress field are analyzed. The deformation style of the steel disk is measured by using CNC three-coordinate measuring instrument.3-D physical models of oil film between parallel interface and deformed interface are built. The models are calculated by using computational fluid dynamics software FLUENT in numerical simulation. The temperature field, pressure field, velocity field and the characteristics of streamline of oil film are obtained. The distribution law of pressure field and temperature field along radial and circumferential direction, and the influence law of temperature field and deformed interface on torque transferred by oil film are obtained.A special HVD test-bed is developed. Based on a large number of experiments, the influence of flow rate, rotational speed difference and deformed interface on temperature field, pressure field, and transferred torque is researched. The experimental results approximately agree with the theoretical analysis results and the validity of theoretical analysis is proved. The research results play a guiding role in the thorough research on HVD technology, and provide technical support for the design of HVD device and application and popularization of HVD technology. |
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