Research on Air-Gap Windage Loss in High-Speed Motorized Spindles Based on Computational Fluid Dynamics
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摘要:
针对高速永磁电主轴因气隙内空气摩擦损耗引发的散热与能效设计难题,揭示定子槽口与轴向通风冷却的耦合作用下风摩损耗的形成机理及涡流演变规律. 首先,分别建立光滑壁面的理想气隙模型与包含18个定子槽口的实际气隙模型;其次,通过对比2种气隙模型在无轴向通风条件下的能量耗散差异,定量评估定子槽口的独立影响;最后,通过施加不同流速的轴向冷却气流,系统评估通风强度对气隙内部流场结构及能量耗散特性的非线性调控作用. 结果表明:定子槽口是导致风摩损耗激增的决定性因素,与光滑壁面理想气隙相比,定子槽口引起的附加损耗增幅近80%;在含定子槽口气隙中,轴向通风对损耗的调控呈现显著的非单调、分阶段特性:在引入微弱轴向通风后,损耗在2.00 m/s时降至最低,降幅超过19%;当流速进入6.00~10.00 m/s的临界区间,流场失稳导致能量耗散急剧跃升超过26%;而当流速超过10.00 m/s后,涡系压制效应主导流场恢复稳定,能量耗散在骤降后呈稳定单调增长趋势.
Abstract:To address the design challenges of heat dissipation and energy efficiency caused by air friction loss in the air gap of high-speed permanent magnet motorized spindles, the formation mechanism of windage loss and the evolution laws of vortex flow under the coupled effect of stator slots and axial ventilation cooling were revealed. First, an ideal air-gap model with smooth walls and a realistic air-gap model containing 18 stator slots were established, respectively. Second, the independent impact of stator slots was quantitatively evaluated by comparing the energy dissipation differences between the two air-gap models under the condition of no axial ventilation. Finally, the nonlinear regulation effect of ventilation intensity on the internal flow field structure and energy dissipation characteristics of the air gap was systematically evaluated by applying axial cooling airflows at different velocities. The results indicate that stator slots are the decisive factor leading to the surge of windage loss. Compared with the ideal air gap with smooth walls, the increase in additional loss caused by stator slots is nearly 80%. In the air gap containing stator slots, the regulation of loss by axial ventilation exhibits significant non-monotonic and multi-stage characteristics: After weak axial ventilation is introduced, the loss decreases to the minimum at 2 m/s, with a decrease of more than 19%; when the flow velocity enters the critical range of 6–10 m/s, the flow field instability leads to a sharp surge in energy dissipation by over 26%; when the flow velocity exceeds 10 m/s, the vortex suppression effect dominates the flow field to restore stability, and the energy dissipation shows a steady and monotonic increasing trend after a sudden drop.
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表 1 电主轴主要参数
Table 1. Main parameters of motorized spindle
参数 取值 额定功率/kW 25 额定转速/r•min–1 30 000 转子护套内外径/mm 76/80 转子护套长度/mm 158 电磁气隙长度/mm 1 槽数/极数/相数 18/4/3 永磁体材料 N35SH 表 2 网格收敛指数(GCI)估算结果
Table 2. Estimation result of grid convergence index (GCI)
参数 数值 N1/N2/N3 2 107 860/3 647 184/4 641 151 r21/r32 1.200 5/1.083 7 P1/W 135.23 P2/W 163.15 P3/W 163.38 p 36.121 ea21 0.206 463 ea32 0.001 41 Pext/W 163.14 GCI21 0.035 1% GCI32 0.010 2% 表 3 理想光壁气隙风摩损耗误差分析
Table 3. Error analysis of windage loss of ideal smooth-walled air gap
转速/(r•min–1) 雷诺数 CFD模拟/W 式(1)预测值/W 绝对误差/% 20 000 5 570 28.62 32.11 10.87 22 000 6 127 37.41 40.76 8.22 25 000 6 963 53.62 56.10 4.42 28 000 7 798 73.80 74.48 0.91 30 000 8 355 89.70 88.50 1.36 35 000 9 748 138.50 130.11 6.45 40 000 11 140 202.23 187.68 7.75 45 000 12 533 277.69 261.00 6.39 50 000 13 925 366.39 350.56 4.52 55 000 15 317 470.58 457.79 2.79 60 000 16 710 592.05 584.08 1.36 65 000 18 102 734.82 730.81 0.55 70 000 19 495 900.76 899.34 0.16 75 000 20 888 1 087.09 1 090.99 0.36 表 4 临界失稳阶段风摩损耗波动特性统计
Table 4. Statistics of windage loss fluctuation characteristics at critical instability stage
Vaxial
/(m•s–1)Pwind/W
最小值Pwind/W
最大值幅值ΔP
/W6.0 171.04 182.44 11.40 7.0 174.01 184.03 10.02 8.0 175.74 185.81 10.07 9.0 177.24 188.33 11.09 10.0 181.55 189.11 7.56 -
[1] 张曙, 张柄生, 卫汉华. 机床的主轴单元(上)[J]. 机械设计与制造工程, 2016, 45(5): 1-10. doi: 10.3901/JME.2014.11.144ZHANG Shu, ZHANG Bingsheng, WEI Hanhua. Machine tool spindle unit (Part1)[J]. Machine Design and Manufacturing Engineering, 2016, 45(5): 1-10. doi: 10.3901/JME.2014.11.144 [2] 高宏力, 孙弋, 郭亮, 等. 机械加工质量预测研究现状与发展趋势[J]. 西南交通大学学报, 2024, 59(1): 121-141. doi: 10.3969/j.issn.0258-2724.20220085GAO Hongli, SUN Yi, GUO Liang, et al. Research status and development trend of machining quality prediction[J]. Journal of Southwest Jiaotong University, 2024, 59(1): 121-141. doi: 10.3969/j.issn.0258-2724.20220085 [3] 郝磊, 刘孟奇, 韩云龙, 等. 高精密机床制造热性能分析与热管理技术研究[J]. 航空精密制造技术, 2024, 60(6): 1-4, 8.HAO Lei, LIU Mengqi, HAN Yunlong, et al. Research on thermal performance analysis and thermal management technology for high precision machine tool manufacturing[J]. Aviation Precision Manufacturing Technology, 2024, 60(6): 1-4,8. [4] Staton D A, Cavagnino A. Convection Heat Transfer and Flow Calculations Suitable for Electric Machines Thermal Models[J]. IEEE Transactions on Industrial Electronics, 2008, 55(10): 3509-3516. doi: 10.1109/TIE.2008.922604 [5] Zhu Z Q, Liang D. Perspective of Thermal Analysis and Management for Permanent Magnet Machines, with Particular Reference to Hotspot Temperatures[J]. Energies, 2022, 15(21): 8189. doi: 10.3390/en15218189 [6] Wang R, Fan X, Li D, et al. Comparison of Two Hollow-Shaft Liquid Cooling Methods for High Speed Permanent Magnet Synchronous-Machines[C]//2020 IEEE Energy Conversion Congress and Exposition (ECCE). Detroit: IEEE, 2020: 3511-3517. [7] Gai Y, Widmer J D, Steven A, et al. Numerical and Experimental Calculation of CHTC in an Oil-Based Shaft Cooling System for a High-Speed High-Power PMSM[J]. IEEE Transactions on Industrial Electronics, 2020, 67(6): 4371-4380. doi: 10.1109/TIE.2019.2922938 [8] Camilleri R, Beard P, Howey D A, et al. Prediction and Measurement of the Heat Transfer Coefficient in a Direct Oil-Cooled Electrical Machine With Segmented Stator[J]. IEEE Transactions on Industrial Electronics, 2018, 65(1): 94-102. doi: 10.1109/TIE.2017.2714131 [9] Chong Y C, Goss J, Popescu M, et al. EXPERIMENTAL CHARACTERISATION OF RADIAL OIL SPRAY COOLING ON A STATOR WITH HAIRPIN WINDINGS[C]//The 10th International Conference on Power Electronics, Machines and Drives (PEMD 2020). Online Conference: IEEE, 2020: 879-884. [10] Liu C, Xu Z, Gerada D, et al. Experimental Investigation on Oil Spray Cooling With Hairpin Windings[J]. IEEE Transactions on Industrial Electronics, 2020, 67(9): 7343-7353. doi: 10.1109/TIE.2019.2942563 [11] Ghahfarokhi P S, Podgornovs A, Kallaste A, et al. Oil Spray Cooling with Hairpin Windings in High-Performance Electric Vehicle Motors[C]//2021 28th International Workshop on Electric Drives: Improving Reliability of Electric Drives (IWED). Moscow: IEEE, 2021: 1-5. [12] Liu C, Gerada D, Xu Z, et al. Estimation of Oil Spray Cooling Heat Transfer Coefficients on Hairpin Windings With Reduced-Parameter Models[J]. IEEE Transactions on Transportation Electrification, 2021, 7(2): 793-803. doi: 10.1109/TTE.2020.3031373 [13] Xu Z, Rocca A L, Arumugam P, et al. A semi-flooded cooling for a high speed machine: Concept, design and practice of an oil sleeve[C]//IECON 2017-43rd Annual Conference of the IEEE Industrial Electronics Society. Beijing: IEEE, 2017: 8557-8562. [14] Zhu T, Wang Y, Geng W, et al. Rotor air-friction loss and thermal analysis of high-speed rotor for axial flux PM motor[C]//2021 23rd European Conference on Power Electronics and Applications (EPE'21 ECCE Europe). Ghent: IEEE, 2021: 1-12. [15] Taras P, Nilifard R, Zhu Z Q, et al. Cooling Techniques in Direct-Drive Generators for Wind Power Application[J]. Energies, 2022, 15(16): 5986. doi: 10.3390/en15165986 [16] Saari J. Thermal Analysis of High-Speed Induction Machines[D]. Helsink: Helsinki University of Technology, 1998. [17] Fang H, Li D, Qu R, et al. Rotor Design and Eddy-Current Loss Suppression for High-Speed Machines With a Solid-PM Rotor[J]. IEEE Transactions on Industry Applications, 2019, 55(1): 448-457. doi: 10.1109/TIA.2018.2871095 [18] Geng W, Zhu T, Zhang Y, et al. Rotor Air-Friction Loss and Thermal Analysis of IPM Rotors for High Speed Axial-Flux Machine[J]. IEEE Transactions on Industry Applications, 2023, 59(1): 779-788. doi: 10.1109/TIA.2022.3210896 [19] 梁腾和, 黄宏立, 马乐, 等. 涡轮机械转子在CO2工质中风摩损耗的数值分析[J]. 厦门大学学报(自然科学版), 2020, 59(4): 547-552. doi: 10.6043/j.issn.0438-0479.201905021LIANG Tenghe, HUANG Hongli, MA Le, et al. Numerical analysis of windage loss of turbomachinery rotor in CO2[J]. Journal of Xiamen University (Natural Science), 2020, 59(4): 547-552. doi: 10.6043/j.issn.0438-0479.201905021 [20] Bilgen E, Boulos R. Functional Dependence of Torque Coefficient of Coaxial Cylinders on Gap Width and Reynolds Numbers[J]. Journal of Fluids Engineering, 1973, 95(1): 122-126. doi: 10.1115/1.3446944 [21] 赵弟宏, 覃珌潭, 张文佳, 等. CO2轴向流动对转子风摩损耗的影响[J]. 厦门大学学报(自然科学版), 2023, 62(5): 842-847. doi: 10.6043/j.issn.0438-0479.202208012ZHAO Dihong, QIN Bitan, ZHANG Wenjia, et al. Effect of CO2 axial flow on rotor windage loss[J]. Journal of Xiamen University (Natural Science), 2023, 62(5): 842-847. doi: 10.6043/j.issn.0438-0479.202208012 [22] 毛玉红, 陈超, 李亚蓉, 等. Taylor-Couette波状涡流场环隙波动的变化特征[J]. 西南交通大学学报, 2025, 60(2): 425-433. doi: 10.3969/j.issn.0258-2724.20230308MAO Yuhong, CHEN Chao, LI Yarong, et al. Fluctuation characteristics of wavy vortex field within annular gap in Taylor-Couette[J]. Journal of Southwest Jiaotong University, 2025, 60(2): 425-433. doi: 10.3969/j.issn.0258-2724.20230308 [23] Dai Y, Li W, Qu H, et al. Study on parameters of T-type cooling system for motorized spindle based on thermal characteristics[J]. The International Journal of Advanced Manufacturing Technology, 2024, 131(9): 5265-5276. [24] Zhao J, Ding Y, Zhang T, et al. Investigating the impact of cruciform stepped spoiler bars on floc formation and flocculation kinetics parameters[J]. Separation and Purification Technology, 2025, 358: 130371. doi: 10.1016/j.seppur.2024.130371 [25] Zhang S, Wang F, Zhang Y, et al. A Comparative Study on Coupled Fluid–Thermal Field of a Large Nuclear Turbine Generator with Radial and Composited Radial–Axial–Radial Ventilation Systems[J]. Machines, 2024, 12(5): 326. doi: 10.3390/machines12050326 [26] 康啊真, 殷瑞涛, 祝兵, 等. 基于LES的跨海桥梁施工期围堰波流力数值模拟[J]. 西南交通大学学报, 2020, 55(3): 537-544, 589.KANG Azhen, YIN Ruitao, ZHU Bing, et al. Numerical simulation of wave-current forces acting on cofferdam for sea-crossing bridge based on large eddy simulation[J]. Journal of Southwest Jiaotong University, 2020, 55(3): 537-544,589. [27] 郑云, 刘志祥, 余志祥, 等. 基于PIV试验的积雪平屋面风场特性研究[J]. 西南交通大学学报, 2023, 58(2): 430-437, 461. doi: 10.3969/j.issn.0258-2724.20210262ZHENG Yun, LIU Zhixiang, YU Zhixiang, et al. Wind field characteristics of snow-covered low-rise building roof based on PIV experiments[J]. Journal of Southwest Jiaotong University, 2023, 58(2): 430-437,461. doi: 10.3969/j.issn.0258-2724.20210262 [28] Bilde K G, Hærvig J, Sørensen K. On the design of compact hydraulic pipe flocculators using CFD-PBE[J]. Chemical Engineering Research and Design, 2023, 194(1): 151-162. doi: 10.1016/j.cherd.2023.04.045 [29] Wang X, Cui B, Wei D, et al. CFD-PBM modelling of tailings flocculation in a lab-scale gravity thickener[J]. Powder Technology, 2022, 396(1): 139-151. doi: 10.1016/j.powtec.2021.10.054 [30] Celik I B, Ghia U, Roache P J, et al. Procedure for Estimation and Reporting of Uncertainty Due to Discretization in CFD Applications[J]. Journal of Fluids Engineering, 2008, 130(7): 78001-78004. doi: 10.1115/1.2960953 [31] Sedrez T A, Decker R K, Da Silva M K, et al. Experiments and CFD-based erosion modeling for gas-solids flow in cyclones[J]. Powder Technology, 2017, 311: 120-131. doi: 10.1016/j.powtec.2016.12.059 -
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