Study of piston offset inhibition method based on the biased center port

The linear compressor is one of the main energy-consuming components in domestic and space refrigeration systems. Due to the asymmetric leakage in the clearance, the piston offset unavoidably causes the piston to deviate from its designed equilibrium position and worsens the compressor performance. In this paper, a new method is proposed to inhibit the piston offset. A biased center port is employed to direct gas from the back chamber to the front at the position close to the back chamber to balance the pressure on the two sides of the piston. To verify this method, a numerical simulation was performed to calculate the mass flow through the clearance and center port channel, and the average pressure difference across the piston. An experimental bench was established to compare the offset of the structures with no center port, unbiased center port and biased center port. Results show that the biased center port can almost eliminate the piston offset at the designed operating condition.