Abstract:In order to design machine tool rapidly, Research on the definition method of user defined feature, which are restricted by Feature-based constraints. It provide the unique discretional method for features, finally built the commonly UDF library of machine tool. Combine with Pro/ENGINEER secondary development package Pro/toolkit, the UDF information could be accurate extracted and reused, develop the UDF feature library system. It provides advanced rapid design tools for machine tools and other products for three-dimensional design, improve design efficiency and lay the founded of computer-aided design. The internal friction of the bearing assembly of centrifugal compressor during high-speed operation generates a lot of heat, which leads to the problem of excessive temperature in the flow field. In this paper, the flow and heat transfer characteristics of refrigerant gas in the rolling bearing assembly of centrifugal compressor are studied. Taking angular contact ball bearings 6009 as research objects, a numerical analysis model for the inner cavity of bearing assembly is established.By comparing the internal temperature field at different rotational speeds, the effect of rotational speed on the heat transfer characteristics in the bearing assembly cavity is revealed. The results show that rotation of bearings causes rotational flow, which increases the flow rate and increases the pressure inside the bearing assembly. With the increase of rotational speed, the velocity of flow field increases and the temperature in bearing chamber decreases to a certain extent. However, as the speed continues to rise, the friction loss increases sharply, the heat generated is greater than the heat transfer capacity of the gas, and the temperature increases accordingly. Finally, the speed under better heat dissipation conditions is obtained.