China Mechanical Engineering ›› 2022, Vol. 33 ›› Issue (18): 2161-2171.DOI: 10.3969/j.issn.1004-132X.2022.18.002

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Simulation and Experimental Research about Temperature Fields of PDMS Cooled by Liquid Nitrogen Jet Impingement

LIU Xu1;SUN Yuli1;ZHANG Guiguan1;QIAN Bingkun1G;AO Hang2;ZUO Dunwen1   

  1. 1.College of Mechanical & Electrical Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing,210016
    2.School of Mechanical Engineering,Dalian University of Technology,Dalian,Liaoning,116024
  • Online:2022-09-25 Published:2022-10-05

液氮射流冲击冷却聚二甲基硅氧烷的温度场仿真和实验研究

刘旭1;孙玉利1;张桂冠1;钱炳坤1;高航2;左敦稳1   

  1. 1.南京航空航天大学机电学院,南京,210016
    2.大连理工大学机械工程学院,大连,116024
  • 通讯作者: 孙玉利(通信作者),男,1970年生,教授、博士研究生导师。研究方向为精密超精密加工技术,现代表面工程技术。E-mail:sunyuli@nuaa.edu.cn。
  • 作者简介:刘旭,男,1997年生,硕士研究生。研究方向为低温磨料气射流加工。
  • 基金资助:
    国家自然科学基金(52075254);大连理工大学精密与特种加工教育部重点实验室研究基金(JMTZ201901);江苏省研究生科研与实践创新计划(KYCX20_0183)

Abstract: In order to explore the changes and distributions of the temperature of PDMS sample being impacted and cooled by the liquid nitrogen jet during the cryogenic micro-abrasive air jet machining the PDMS microchannels, this paper proposed a systematic research method of temperature that composed of temperature measurement experiments, Becks inverse estimation method fitting and APDL temperature field simulation. The errors between the final simulation results and the temperature measurement ones are only 1.735%. The simulations find that it will take 5.747 s for the surfaces to reach the obvious embrittlement temperature -147 ℃. PDMS may not reach a machinable embrittlement state at the moment of contact with liquid nitrogen, so it is necessary to pay attention to the pre-cooling time before machining. The simulation data was used to fit the cooling rate of PDMS to -147 ℃, and the cooling rate was used as a reference to predict the pre-cooling time required in the actual machining. By comparing the cooling rate, it is found that the cooling rate in the depth range of 0~100 μm from the surface of the PDMS specimen is 22.054% faster than that in the depth range of 0~1500 μm, and the cooling rate of the aluminum alloy workbench is about 22.311% higher than that of the adiabatic workbench.

Key words:  , polydimethylsiloxane(PDMS), cryogenic micro-abrasive air jet, Becks inverse estimation method, APDL(ANSYS parametric design language) temperature field simulation

摘要: 为探究低温微磨料气射流加工聚二甲基硅氧烷(PDMS)微流道过程中PDMS试样受液氮射流冲击冷却的温度变化和分布,提出了测温实验Beck反求算法拟合APDL温度场仿真的系统研究方法,仿真结果与测温结果的误差仅1.735%。仿真发现,表面到达明显脆化温度-147 ℃需要5.747 s,说明PDMS无法在接触液氮的瞬间就达到可加工的脆化状态,有必要重视加工前的预冷却时间;又通过仿真数据拟合了PDMS冷却至-147 ℃的冷却速度,以冷却速度为参考预测了实际加工中所需的预冷却时间。对比冷却速度发现,距PDMS试样表面0~100 μm深度范围内的冷却速度比0~1500 μm深度范围内冷却速度快22.054%,PDMS试样放置在铝合金工作台上的冷却速度比绝热工作台上快22.311%。

关键词: 聚二甲基硅氧烷(PDMS), 低温微磨料气射流, Beck反算法, APDL温度场仿真

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