Research On Performance Of The Condenser And Spiral Cyclone Sparator Used For The Hydraulic System Appliable To Dusty Environment

As an important hydraulic accessory, the cooler has an important role during normal operation of the hydraulic system. Compared with refrigerant cooler, the air-cooled cooler has poor cooling effect and the overheat problem of hydraulic oil can't be solved completely. So, as for the refrigerant cooler used in construction machinery, it's necessary to research on the cooler and its component parts. The condenser and spiral cyclone separator studied in this paper can lay the foundation for the development of the refrigerant cooler, which will be used for the hydraulic system of the construction machinery adapted to dusty environment. Therefore, for the normal work of refrigerant cooler, it's significant to analyze the dust deposition mechanism on the heat transfer and select a reasonable method to reduce the content of dust in the air flow.In this paper, based on the hydraulic system of an application object, the design calculation of the finned tube condenser is completed according to the calculated heat dissipation power. Combined with the atmospheric environment of the port, the impact of port environment on heat transfer performance of the condenser is analyzed. On the basis of comparison, the spiral cyclone separator is selected as the dust removal device of the refrigerant cooler used in dusty environment, and numerical simulation on the separator is completed by the computational fluid dynamics (CFD) analysis method. The three-dimensional strongly swirling flow in the separator is simulated based on the nonisotropic RSM model, the characteristics of speed, pressure and turbulence, which can reveal the flow state and energy loss inside the spiral cyclone separator, have also been obtained by simulation. The gas-solid two-phase flow inside the separator is simulated based on DPM model, the classification efficiency of the separator is obtained and the paths of particles are tracked with the coupling discrete random walk model. On the basis of changing the operation and structure parameters, the separation characteristics are analyzed when the wind speed, the number of spiral circle and the height of cone are different. These can provide basis for the structure optimization of the separator.Based on the calculated parameters of the finned tube condenser, the heat transfer model of the finned tube is built. The coupled heat transfer of fins is analyzed by simulation, and the corresponding relation between the heat transfer performance and wind speed is obtained. The species of fouling are described in this paper, and the deposition model of particle fouling is built, at last, the mechanism of particle deposition on the heat exchanger surface is revealed and the main factors that affect the particle deposition are analyzed. In addition, the heat transfer performances of the finned tube condenser with different fouling thickness are obtained by simulation. The results show that the increase of the fouling will lead to lower wind speed and higher flow resistance. Compared with the clean heat transfer surface, the heat transfer rate of the finned tube has decreased by16%when the thickness of fouling reaches to0.25mm.