Simulation of high speed single screw compressor in fuel cell

According to the volume compressor's quasi-linear relationship between flow rate and rotational speed,it was pointed out that the high speed compressor which provides large flow rate under small package can satisfy the basic demand of fuel cells on vehicles.A mathematical model for high speed single screw compressor was established.The compressing process was modeled on the assumption of the working chamber as a control volume,to which the conservation equations of mass and energy were applied,while the heat exchange and air leakage were taken into consideration.According to the model,the physical properties of compressed air,the compressor's volume efficiency and energy dissipation under different rotational speed were calculated.Simulation results show that the ratio of mass flow to device volume obviously increases with increase of the rotational speed. On the assumption of fixed mass flow,increasing the compressor's rotational speed can decrease the device's volume.However more energy is dissipated because the heat transfer effect is weakened.