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. 2024 May 29;15(6):717.
doi: 10.3390/mi15060717.

Study on the Pumping Performance and Structure Parameters Optimization of High-Speed Small Compound Molecular Pump

Zhi Chen  1   2 , Lei Zhang  1 , Zhizuo Li  1 , Zhizhong Zhang  3 , Guojun Zhang  2 , Fenglin Han  1
Affiliations

Study on the Pumping Performance and Structure Parameters Optimization of High-Speed Small Compound Molecular Pump

Zhi Chen et al. Micromachines (Basel). .

Abstract

A molecular pump is the core component of vacuum systems in portable mass spectrometers and other analytical instruments. The forms of the existing molecular pumps mainly are the combinations of vertical bleed and compression channel, which have the shortcomings of heavy mass and large volume, which seriously restricts the application and development of portable mass spectrometers. Aiming at the problems of low strength and insufficient pumping performance under the miniaturization constraints (mass of 1.8 kg; exhaust diameter of 25 mm) of molecular pumps, a compound pump consisting of a horizontal bleed channel and multi-stage spiral compression channel is proposed. The pumping principle of the compound molecular pump is analyzed to obtain its preliminary structural size parameters. The test particle Monte Carlo method is presented for establishing an aerodynamic model for a high-speed small compound molecular pump, which can be used to investigate the pumping performance of bleed blades and compression channels in a thin air environment. On the basis of the aerodynamic model, the NNIA multi-objective optimization algorithm is presented to optimize the structural parameters of the compound molecular pump. After structural parameter optimization, the maximum flow rate and compression ratio of the compound molecular pump are increased by 13.6% and 41.6%, respectively. The experimental results of the pumping performance show that the predicted data of the aerodynamic model are in good agreement with the experimental data, with an error of 12-27%. Namely, the established aerodynamic model has high accuracy and the optimized structural parameters of the compound molecular pump can provide basic conditions for the large-scale application and promotion of portable mass spectrometers.

Keywords: aerodynamic model; compound molecular pump; pumping performance; structure parameters optimization; thin air environment.

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Conflict of interest statement

All authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Figures

Figure 1
Figure 1
The structural diagram of the high-speed small compound molecular pump pumping unit.
Figure 2
Figure 2
The pumping principle of bleed stage rotor.
Figure 3
Figure 3
The schematic diagram of the bleed stage rotor pumping structure.
Figure 4
Figure 4
The structural diagram of the compression stage rotor.
Figure 5
Figure 5
The structure diagram of the compression stage stator.
Figure 6
Figure 6
The boundary condition of inlet and outlet.
Figure 7
Figure 7
The simulation model and boundary condition of the bleed stage rotor.
Figure 8
Figure 8
The simulation results of single blade channel at the speed of 90,000 rpm.
Figure 9
Figure 9
The multi-stage spiral gas compression channel of the compression stage rotor.
Figure 10
Figure 10
The simulation results of single-stage compression channel at the speed of 90,000 rpm.
Figure 10
Figure 10
The simulation results of single-stage compression channel at the speed of 90,000 rpm.
Figure 11
Figure 11
The interaction of blade spacing and blade chord length on the flow rate.
Figure 12
Figure 12
The interaction of blade inclination angle and blade chord length on the flow rate.
Figure 13
Figure 13
The interaction of blade spacing and blade inclination angle on the flow rate.
Figure 14
Figure 14
The interaction of blade spacing and blade chord length on the compression ratio.
Figure 15
Figure 15
The interaction of blade inclination angle and blade chord length on the compression ratio.
Figure 16
Figure 16
The interaction of blade spacing and blade inclination angle on the compression ratio.
Figure 17
Figure 17
The Pareto solution set for the structural parameters of compound molecular pump.
Figure 18
Figure 18
The experimental platform for testing the pumping performance of the high-speed small compound molecular pump.
Figure 19
Figure 19
The comparison results of the experimental value and simulation predicted value of the maximum compression ratio.
Figure 20
Figure 20
The comparison results of the experimental value and simulation predicted value of the maximum flow rate.
Figure 21
Figure 21
Ultimate pressure test results of small compound molecular pump.
See this image and copyright information in PMC

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