【作者】 李燕；

【导师】 金东旭；

【作者基本信息】 大连理工大学 ， 制冷及低温工程， 2013， 硕士

【摘要】 随着现代工业的迅速发展,以能源为中心的环境、生态等问题日益加剧,节能是非常重要的,也是当务之急。强化换热技术的应用不但节能环保,而且节约了投资和运营成本。所以强化换热技术一直以来都是一个非常重要的课题,尤其是脉动流动强化换热受到各国研究者的青睐。本文采用实验的方法对凹槽通道内层流脉动流动强化换热进行了实验研究,分析了在不同的雷诺数、脉动频率、脉动振幅以及凹槽通道的槽深(6mm,9mm和12mm),槽宽(12mm,18mm,24mm)各种参数的影响下,强化换热效果的变化情况。并且在实验段其压力进行了测量,分析压力梯度随脉动的变化情况。结果表明对流体施加脉动扰动能够显著地提高凹槽通道的传热能力。稳态时,局部努赛尔数随着雷诺数的增大而增大；脉动时,努赛尔数也随着雷诺数的增大而增大,但都高于对应稳态时的努赛尔数,且强化传热因子随着脉动频率先增大后减小,存在最优的脉动频率。并且强化换热效果受槽深及槽宽的影响。压力梯度的振幅分别随着雷诺数、脉动振幅以及脉动频率的增大而增大。更多还原

【Abstract】 With the rapid development of modern industry, the problems of environmental and ecological are increasing severely, so energy conservation is very important, and imperative. The application of the heat transfer enhancement technology can not only conserve energy and protects the environment, but also reduce the investment and the operating cost. So the heat transfer enhancement technology is always a very important topic, especially the heat transfer enhancement by the pulsating flow which is studied by researchers from all over the world.In this paper, the heat transfer enhancement by laminar pulsating flow in rectangular grooved channels was experimentally investigated. Effects of Reynolds number, pulsation frequency, pulsation amplitude and groove depth (6mm,9mm and12mm), groove width (12mm,18mm and24mm) on the heat transfer enhancement were studied. And in the experiment section, two pressure points are used to measure its pressure respectively, and we have an analysis on the changes of pressure gradient along with the changes of the pulsating flow.Results show that pulsating disturbance can significantly improve the heat transfer ability of the grooved channel. In the steady state, the local Nusselt number increases with the increase of Reynolds number. In the pulsating flow, the Nusselt number also increases with the increase of Reynolds number. But the Nusselt number in the pulsating flow is higher than the Nusselt number of the corresponding steady-state. The heat transfer enhancement factor first increases and then decreases with the pulsation frequency and the Strouhal number, so there exist an optimal pulsation frequency. The heat transfer enhancement factor is influenced by the groove width and groove depth. The amplitude of pressure gradient increases with the increase of Reynolds number, the pulsation amplitude and the pulsation frequency.更多还原