| Summary: | 碩士 === 國立中山大學 === 機械工程學系研究所 === 89 === A turbomolecular pump (TMP) with good performance must have higher compress ratio and higher pumping speed. At the same time, the performance of turbomolecular pump depends on blade geometries and the rotational speed. When design the blade of Turbomolecular Pump, the blade geometries including, the blade angle, the blade spacing, the blade chord, the spacing-chord ratio, the tip diameter, the root diameter, and the number of blades and as well as the rotational speed of the rotor must be considered.
In this paper the simulation for gas molecular behavior is obtained by the Monte Carlo method. Therefore, a Maxwellian distribution of particles at the inlet and outlet of the flow region and diffuse reflection for the particles that collide with the walls are assumed. Models of this type have been applied to the two-dimensional case. The most important result is to compare the performance between turbomolecular pumps with curve style and plane style of blades. Furthermore, that direct multi-stage simulation (DMS) by Monte Carlo method is used in this paper. The compression ratio multiplication (CRM) method is the improved due to the considering the change of velocity distribution of molecular at the adjacent stages.
From results of the simulation, the effect upon the geometric parameters of the blades and the arrangement in the multi-stage are concluded, that are very useful in designing the turbomolecular.
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