Search

The scroll compressor is a kind of positive-displacement compressor applied in refrigeration systems, heat pump systems, and air conditioner systems. Using the spring smoothing method and considering the heat transfer, the numerical simulation model of the scroll compressor is established under standard working conditions. The results show that the CFD model is well validated by the experiment result. The compressor performance and the working process are analyzed. The pre-compression and the over-compression phenomenon are also studied. Moreover, the temperature distribution and velocity distribution of gas flow in the compressor are illustrated. The result shows that the pre-compression can improve the performance of the scroll compressor and the optimization of the suction channel geometry can provide a smoother suction process. Under the combined effect of the pre-compression and heat transfer, the refrigerating capacity is increased by approximately 0.54 kW and the volume efficiency is increased by approximately 2.2%. The additional power loss due to over-compression is 47.6615 W, and the setting of over-compression discharges can reduce the pressure and power loss. This study is helpful to the performance prediction and the structural optimization of the scroll compressor. [ABSTRACT FROM AUTHOR]

The dry scroll vacuum pump is a kind of variable capacity dry vacuum pump that is applied in chemical, pharmaceutical, semiconductor, and scientific instruments. Analyzing the thermodynamic characteristics of the scroll vacuum pump and studying the impact of operating temperature on its consistent performance are necessary for the design and application of the cooling system of the scroll vacuum pump. Based on the dynamics mesh method, the computational fluid dynamics (CFD) simulation model of a multi-stage dry scroll vacuum pump is established in this study. Under the suction pressure of 1000 Pa, the simulation calculation is carried out at different operating temperatures of fixed scrolls (25 °C, 45 °C, and 65 °C). The results show that the pumping speed, the gas compression power, and the energy efficiency ratio are significantly affected by different temperatures. The operating temperature of the pump has been reduced from 65 °C to 25 °C, the pumping speed is increased by approximately 5.97%, the gas compression power is increased by approximately 4.32%, and the energy efficiency ratio is increased by approximately 1.745%. This research provides a transient simulation method using dynamic mesh technology for the study of the dry scroll vacuum pump, and the results can provide a theoretical basis for the design and application of the cooling system of the dry scroll vacuum pump. [ABSTRACT FROM AUTHOR]

The dry scroll vacuum pump is a kind of variable capacity dry vacuum pump that is applied in chemical, pharmaceutical, semiconductor, and scientific instruments. Analyzing the thermodynamic characteristics of the scroll vacuum pump and studying the impact of operating temperature on its consistent performance are necessary for the design and application of the cooling system of the scroll vacuum pump. Based on the dynamics mesh method, the computational fluid dynamics (CFD) simulation model of a multi-stage dry scroll vacuum pump is established in this study. Under the suction pressure of 1000 Pa, the simulation calculation is carried out at different operating temperatures of fixed scrolls (25 °C, 45 °C, and 65 °C). The results show that the pumping speed, the gas compression power, and the energy efficiency ratio are significantly affected by different temperatures. The operating temperature of the pump has been reduced from 65 °C to 25 °C, the pumping speed is increased by approximately 5.97%, the gas compression power is increased by approximately 4.32%, and the energy efficiency ratio is increased by approximately 1.745%. This research provides a transient simulation method using dynamic mesh technology for the study of the dry scroll vacuum pump, and the results can provide a theoretical basis for the design and application of the cooling system of the dry scroll vacuum pump.

Based on CFD method and dynamics mesh method, the transient flow simulation model of dry scroll vacuum pump was established. Numerical calculation was carried out under three kinds of typical working conditions of viscous flow state including under-compression, slightly over-compression and over-compression. Simulation results are in line with the results of experiment or theoretical calculation on the whole. The maximum error of pumping speed between the simulation and the experiment is about 30%, and the minimum is close to 10%. The predicted compression power accords with the theoretical prediction of approximate polytropic process. The simulation pressure inside the pump also has a consistent change process with experimental results. The contrast and analysis of the simulation model and the physical experiments suggest that the further correctly modified geometric parameters and boundary conditions according to practical situations can significantly improve the accuracy of the numerical calculation. Further analysis of the main flow phenomena and characteristics of scroll compression chamber at the discharge side during the discharge process confirms that under-compression and over-compression lead to the large variation of gas pressure and dramatic fluctuation of compression torque. [ABSTRACT FROM AUTHOR]