Recently, the single screw compressor (SSC) has been applied in the low-temperature heat pump system with the purpose of achieving higher system efficiency. However, the traditional SSC with even-grooves screw rotor behaves high torque fluctuation to the motor, thanks to its work synchronously and doubled compressed gas-induced torque on the screw rotor axis. It is more serious in the low-temperature heat pump system because of the higher pressure ratio. In this paper, an odd-grooves screw rotor design is proposed to smooth the compressed gas-induced torque on the screw rotor axis, by arranging the two compression chambers work alternatively. A dynamic model for the screw rotor is established to calculate the gas force and the gas-induced torque on screw rotors under different working conditions. The results show that the odd-grooves screw rotor design can remarkably reduce the gas-induced torque fluctuation of the SSC. Meanwhile, the maximal load on the bearing caused by the odd grooves design could be controlled below the maximum allowable load of the bearing.

近来，单螺杆压缩机（SSC）已应用于低温热泵系统，以实现更高的系统效率。然而，传统的带有偶数槽螺杆转子的SSC由于其同步工作并且在螺杆转子轴上加倍压缩气体引起的扭矩，因此对电机表现出较大的扭矩波动。在低温热泵系统中，由于压比较高，这种情况更为严重。在本文中，提出了一种奇数槽螺杆转子设计，通过布置两个压缩室交替工作来平滑螺杆转子轴上的压缩气体引起的扭矩。建立了螺杆转子动力学模型，计算了螺杆转子在不同工况下的气体力和气体感应扭矩。结果表明，奇数槽螺杆转子设计可以显着降低SSC的气体引起的扭矩波动。同时，奇数槽设计对轴承造成的最大载荷可以控制在轴承的最大允许载荷以下。