• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>International Journal of Heat and Mass Transfer >Numerical simulation of laminar breakdown and subsequent intermittent and turbulent flow in parallel-plate channels: Effects of inlet velocity profile and turbulence intensity
【24h】

Numerical simulation of laminar breakdown and subsequent intermittent and turbulent flow in parallel-plate channels: Effects of inlet velocity profile and turbulence intensity

机译：平行板通道中层流破裂及随后的间歇和湍流流动的数值模拟：入口速度分布和湍流强度的影响

获取原文
获取原文并翻译 | 示例
       
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The nature of flow development in a parallel plate channel has been investigated by making use of a newly developed model of intermittency. That model, taken together with the RANS equations of momentum conservation, the continuity equation, and the SST turbulence model, was employed to provide a complete chronology of the development processes and the derived practical results. A major focus of the work is the effect of inlet conditions on the downstream behavior of the developing flow. It was observed that the flow development process depends critically on the specifics of the inlet conditions characterized here by the shape of the velocity profile and the magnitude of the turbulence intensity. Two velocity profile shapes (flat and parabolic), are regarded as limiting cases. Similarly, two turbulence intensities, Tu = 1% and 5%, are employed. From the standpoint of practice, the relationship between the friction factor and the Reynolds number is most significant. It was found that this relationship reflects that of standard practice for only one of the investigated cases (flat velocity profile, Tu = 5%). For the other cases (flat profile, Tu = 1% and parabolic profile, Tu = 1% and 5%), the breakdown of laminar flow is delayed and the onset of full turbulence occurs rather abruptly at Re ～10,000. Three unique fully developed flow regimes are existent, depending on the inlet conditions and on the value of the Reynolds number. In addition to the standard laminar and fully turbulent regimes, another regime, fully developed intermittent, can occur. Specifically, in the latter regime, laminar and turbulent flows occur intermittently.
机译：通过使用新开发的间歇模型，研究了平行板通道中流动发展的本质。该模型与动量守恒的RANS方程，连续性方程和SST湍流模型一起使用，可为开发过程提供完整的时间顺序并得出实际结果。这项工作的主要重点是入口条件对正在发展的水流下游行为的影响。已经观察到，流动发展过程主要取决于入口条件的具体情况，在此以速度分布图的形状和湍流强度的大小为特征。两种速度轮廓形状（平面和抛物线形）被视为极限情况。类似地，采用两个湍流强度Tu = 1％和5％。从实践的角度来看，摩擦系数和雷诺数之间的关系最为重要。结果发现，这种关系仅反映了一种情况下的标准实践（平面速度曲线，Tu = 5％）。对于其他情况（平面轮廓，Tu = 1％，而抛物线轮廓，Tu = 1％和5％），层流的破裂被延迟，并且在Re〜10,000时突然发生了完全湍流。根据入口条件和雷诺数的值，存在三种独特的充分发展的流动状态。除了标准的层流和完全湍流状态外，还可能出现另一种完全发展的间歇性状态。具体地，在后一种情况下，层流和湍流间歇地发生。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号