关键词: 超高速电机, 风摩损耗, 流体分析, 温度场分析

Abstract: Downhole compressors in natural gas wells are driven by ultra-high-speed motors to generate high-pressureratio gas flows, thereby enhancing production and water drainage gas recovery. For downhole confined spaces, AC motors need to meet the requirements of small size, ultra-high speed, and high temperature resistance, with the characteristics of high power density and high aspect ratio. At the same time, they should also achieve fast start stop and smooth speed regulation. The poor heat dissipation conditions downhole are not conducive to reducing the temperature of the motor, and long-term high load operation will affect the working performance and service life of the motor. This study focuses on the friction and heat dissipation analysis of a self-developed ultra-high-speed motor, which has a rated speed of 30 000 r/min and a rated power of 120 kW. Windage losses flow models and heat conduction models within microchannels are established to calculate the effects of different rotor speeds, stator slot dimensions, and media on rotor surface windage losses and motor temperature distribution. The research indicates that rotor surface windage losses is proportional to the 2. 947 1th power of rotor speed. It is positively correlated with stator slot width and slot opening chamfer, with a 15. 94% reduction in windage losses observed when the slot width is 2. 0 mm and the slot depth is 1. 0 mm. When helium is used as the air-gap medium, it can effectively reduce wind friction loss, achieving a reduction of 79. 1% compared to air. High temperatures and
pressures lead to increased medium density, thereby elevating windage friction loss. By simulating the downhole environment and incorporating heat flux, the maximum rotor temperature of the motor is found to be 402 K, with a temperature difference of approximately 21 K between the rotor and stator. This study provides key data support for the design and performance optimization of downhole motors under complex and harsh working conditions. Based on this data, effective measures to reduce motor temperature, improve operating efficiency and reliability can be further explored to better meet the practical needs of downhole operations.

Key words: ultra-high-speed motors, windage losses, fluid analysis, temperature field analysis