Translated Abstract
The water flooded single screw compressor has many advantages such as simple structure, excellent mechanical balance, oil free compressed gas and low exhaust temperature, etc. It has good development potential in food, textile, pharmaceutical and other fields. The research results of domestic and foreign scholars and the market selection indicate that water-lubricated sliding bearings will be the future trend. But the gaterotor water-lubricated hydrodynamic thrust bearing used for the water flooded single screw compressor on the market at present cannot achieve hydrodynamic lubrication, and it can easily cause bearing abrasion and affect performance of the compressor. Compared with the hydrodynamic thrust bearing, the hydrostatic thrust bearing can make the friction pair in the full liquid friction state. However, little attention has been focused on the hydrostatic thrust bearing used in the water flooded single screw compressor. The paper puts forward the annular recess hydrostatic thrust bearing so as to improve the lubrication performance of the gaterotor thrust bearing, and the research work are shown as follows:
The mathematical models of the compression chamber volume and gas pressure in the screw groove are established in this paper, based on geometrical characteristics and meshing pair of the water flooded single screw compressor. A dynamic analysis of the gaterotor shafting was made to obtain the changes of the stress on gaterotor thrust bearing. These studies provide the basis for the design of main parameters of the gaterotor hydrostatic thrust bearing and for the lubrication analysis.
According to the working principle of hydrostatic thrust bearing, the paper puts forward the gaterotor hydrostatic thrust bearing with the structure of an annular recess and also proposes the design of main parameters by taking the water flooded single screw compressor with the exhaust volume of 20 m3·min-1 as an example. Then the paper studies the influences of several main structural parameters, such as throttle ratio, supply pressure and bearing clearance, on bearing stiffness and obtains the optimal selection range of these main structural parameters, and summarizes general design process for the gaterotor hydrostatic thrust bearing. The optimal parameters of the thrust bearings can be quickly calculated by programming for different models under different conditions.
The governing equations of the water film in the gaterotor hydrostatic thrust bearing clearance is presented in the paper, based on the N-S equation. The paper also applies the numerical simulation method to analyze pressure distribution of the water film and the load capacity under different main structural parameters of bearings. The result indicates that the load capacity of the bearings reduces with the increase of the thickness of the water film, the load capacity of the bearings first increases and then remains basically unchanged with the increase of the diameter of the inlet opening or the depth of the water tank, and the load capacity of the bearings slightly decreases with the increase of the rotating speed of the bearing, and an increase in supply pressure led to a linear increase in load capacity. The feasibility of the numerical model is verified through comparing the simulation results with the design results. It appears that the performance of annular recess hydrostatic thrust bearing is better than that of cross recess hydrodynamic thrust bearing. These results provide a reference for optimal design of structural parameters and lubrication analysis of the gaterotor hydrostatic thrust bearing.
Translated Keyword
[Hydrostatic thrust bearing, Load capacity, Single screw compressor, Water lubrication]
Corresponding authors email
