Numerical Study on the Transient Pneumatic Characteristics of a Piston-Type Air Compressor During the Compressing Process

To investigate the pneumatic characteristics of a piston-type air compressor during the rapid transient processes of intake and compression, this study establishes a computational model incorporating the tank, valves, cylinder, intake and discharge pipe, etc. Utilizing the dynamic mesh method combined with user-defined functions, numerical calculations were performed to analyze the compression process, focusing on pressure variation patterns at various positions inside the cylinder and their impact on compressor performance. The purpose is to enhance understanding of these dynamics. Key findings reveal that during the intake phase, pressure at all monitored points rapidly decreases, with the most significant pressure changes occurring directly below the intake valve. Pressure variations on the surfaces of the intake and discharge valves exhibit high consistency. However, during compression, negative pressure changes become more pronounced. The pressures on the top, side walls, and bottom of the cylinder rapidly decrease as the compression ends. Furthermore, as air flows into the storage tank, its pressure decreases but remains mostly stable until equilibrium is reached, causing the tank pressure to rise. Finally, significant low-pressure areas were observed in small corners below the pipe, while higher pressure values were found in larger corners above the side, demonstrating flow characteristics and energy loss under different geometric conditions.