Continuum-based slip model and its validity for micro-channel flows

来源 :Chinese Science Bulletin | 被引量 : 0次 | 上传用户:wensiuu
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
In this paper, the low Mach number he- lium and nitrogen flows in micro-channels are inves- tigated numerically with variations of inlet to outlet pressure ratios, aspect ratios, out pressures and fluid mediums by using different continuum-based slip models. Theoretical solutions based on perturbation expansions of the Navier-Stokes equations have been developed under different order slip conditions. The validity of slip models has been examined by the corresponding experiments and the DSMC method at different Knudsen numbers. Simulations have shown good predictions of the compressibility, rarefaction and thermal creep effects on micro-channel flows with the present slip models. The higher order slip models relatively decrease the rarefaction effects comparing with a first-order slip model. Both of the Knudsen number and the Reynolds number have been identified as key parameters, which govern the rarefaction effects and thermal creep effects, respec- tively. The present slip models have been also dem- onstrated to be appropriate for micro-channel nitro- gen flows with the Knudsen number less than 0.15, and the higher order slip conditions improve the Na- vier-Stokes predictions in the slip flow regime with Kn<0.08. However, the continuum-based slip models significantly under-predict the rarefaction effects in the transitional flow regime as the Knudsen number exceeds 0.2. In this paper, the low Mach number he- lium and nitrogen flows in micro-channels are in-tigated numerically with variations of inlet to outlet pressure ratios, aspect ratios, out pressures and fluid mediums by using different continuum-based slip models. Theoretical solutions based on perturbation expansions of the Navier-Stokes equations have been developed under different order slip conditions. The validity of slip models has been examined by the corresponding experiments and the DSMC method at different Knudsen numbers. Simulations have shown good predictions of the compressibility, rarefaction and thermal creep effects on micro-channel flows with the present slip models. The higher order slip models are less than the rarefaction effects comparing with a first-order slip model. Both of the Knudsen number and the Reynolds number have been identified as key parameters , which govern the rarefaction effects and thermal creep effects, respecively-tively. The present slip models hav e been also dem-onstrated to be appropriate for micro-channel nitro-gen flows with the Knudsen number less than 0.15, and the higher order slip conditions improve the Na-vier-Stokes predictions in the slip flow regime with Kn <0.08. However, , the continuum-based slip models significantly under-predict the rarefaction effects in the transitional flow regime as the Knudsen number exceeds 0.2.
其他文献
  背景介绍封装电源/地网络的主要电性能指标真实的封装设计案例结论
会议
目的 分析微骨一号外敷治疗急性痛风性关节炎的护理效果.方法 选择我院急性痛风性关节炎患者共80例,数字表随机分2组每组40例,对照组的患者给予常规治疗和护理,观察组在该基
目的 探讨家属参与式护理在小儿喘息性支气管炎伴发热症状护理中的应用效果.方法 以2018年1月~2019年2月接受治疗的100例小儿支气管炎伴发热患者作为研究对象,按照入院先后顺
目的 分析指状式10%盐水冰袋联合利多卡因胶浆在肛周手术术后的应用效果.方法 选择我院2019年2月到2019年11月收治的97例痔疮切除术患者,按照随机分组方式,将其分为观察组与对
目的 对1例晚期肾癌患者在服用帕唑帕尼后出现严重不良反应给予综合护理.方法 对患者各种不良反应,采取对应护理措施.结果 患者不良反应明显改善.结论 有效护理措施能很好的
目的 探析在慢性盆腔炎患者应用盆腔治疗仪治疗时实施整体护理模式的护理效果.方法 选取我院2018年11月~2019年11月收治的42例慢性盆腔炎患者作为研究对象,所选患者均于我院应
会议
目的 分析综合护理干预对改善慢性肾衰患者心理状态的护理效果.方法 选取我院2018年6月~2019年6月收治的慢性肾衰患者共90例,采取随机分类的方法分为观察组和实验组,对比两组
会议
会议