In order to meet the requirements of output torque, efficiency and compact shape of micro-spindles for small parts machining, a two-stage axial micro air turbine spindle with an axial inlet and outlet is proposed. Based on the k-ω turbulence model of SST, the flow field and operation characteristics of the two-stage axial micro air turbine spindle were studied using computational fluid dynamics (CFD) combined with an experimental study. We obtained the air turbine spindle under different working conditions of the loss and torque characteristics. When the inlet pressure was 300 KPa, the output speed of the two-stage turbine was 100,000 rpm, 9% higher than that of a single-stage turbine output torque. The total torque reached 6.39 N·mm, and the maximum efficiency of the turbine and the spindle were 42.2% and 32.3%, respectively. Through the research on the innovative structure of the two-stage axial micro air turbine spindle, the overall performance of the principle prototype has been significantly improved and the problems of insufficient output torque and low working efficiency in high-speed micro-machining can be solved practically, which laid a solid foundation for improving the machining efficiency of small parts and reducing the size of micro machine tool.

为了满足小零件加工中微主轴的输出转矩，效率和紧凑型的要求，提出了一种带有轴向入口和出口的两级轴向微型空气涡轮机主轴。基于SST的k-ω湍流模型，利用计算流体力学（CFD）结合实验研究，研究了两级轴向微型空气涡轮机主轴的流场和工作特性。我们获得了空气涡轮机主轴在不同工作条件下的损耗和扭矩特性。当入口压力为300 KPa时，两级涡轮的输出转速为100,000 rpm，比单级涡轮的输出扭矩高9％。总扭矩达到6.39 N·mm，涡轮和主轴的最大效率分别为42.2％和32.3％。