High Vacuum Dry Pump

Miniaturization and integration are important trends in the development of dry vacuum pumps. High vacuum dry pump is a representative new type of dry pump. In this paper, the single helix rotor, one of the important components of high vacuum dry pump, is studied numerically. By analyzing the important parameters of geometric model and combining the program idea of direct simulation Monte Carlo, the working process of single helix rotor is simulated. The influence mechanism of geometric parameters of single helical rotor on pumping efficiency is simulated, and the parameter adjustment mechanism which affects the performance of high vacuum dry pump is obtained, which provides theoretical basis and guidance for the design of high vacuum dry pump.
In recent years, the screw vacuum pump (screw pump) has attracted much attention. Its rotor adopts spiral space curve, which has many obvious advantages, such as smooth transmission medium, low noise, high allowable speed, compact structure, long service life and so on. Screw pumps are widely used in industry and national defense, such as chemical pharmaceuticals, aerospace, petrochemical, semiconductor equipment, special gas recovery, general industry and so on. Single screw pump is a kind of screw pump. It uses high-speed rotating rotor surface to carry gas molecules, so that the gas is continuously pumped out of the pump body. It has the characteristics of minimal disturbance and smooth transmission.
Cleaning, miniaturization and simplification are important trends in the development of vacuum acquisition equipment and systems, among which the most representative is the dry vacuum acquisition technology directly discharged into the atmosphere in the high vacuum range. The high vacuum dry pump is composed of a variety of high-speed rotating uniaxial pumps, and a single helical rotor is used near the suction side to complete the suction transmission process of large displacement. In the process of gas transmission, the selection of structural design parameters such as blade shape, number, size and inclination of helical rotor will have a great influence on its pumping performance.
The basis of direct simulation Monte Carlo (DSMC) method is to track the trajectory of the simulated molecules. This process starts from the given initial state. The selection of the initial state is arbitrary under the condition that the MACRO-FLOW is a steady flow. In the tracking process, the parameters of the simulated molecules in different states are recorded, and then the macro-state of the gas can be obtained by further statistical averaging. The parameters of states. The helical stage is mainly located in the molecular flow region in the working process. Based on Bird's improved DSMC method, the numerical simulation method of the gas flow field in the helical groove channel in the rotor model can be established.
In the application of high vacuum dry pump, the performance of helical rotor can be simulated effectively.
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