摘要
为了研究非稳态尾迹对平板表面流动和换热的影响,本文将非稳态尾迹引起的主流速度脉动简化为正弦变化,通过数值的方法研究了脉动频率和振幅对平板壁面边界层流动和换热的影响,研究结果表明:边界层内的速度、壁面温度、壁面摩擦系数和平均换热系数随着时间的变化做周期性脉动;边界层内流动与主流之间存在着相位差,壁面距离越小,相位差越大;边界层内的速度和壁面摩擦系数脉动幅度的大小与主流脉动频率和振幅成正比;壁面温度和壁面平均换热系数的波动大小与主流脉动频率成反比,与脉动振幅成正比,当主流脉动频率和脉动振幅增加到一定值后,靠近壁面的地方出现回流,回流强度与脉动频率和振幅成正比。
In order to study the effect of unsteady wake on the flow and heat transfer of a plate, main stream velocity fluctuation caused by unsteady wake is simplified as sine wave variety. Numerical analysis is conducted to investigate the influence of inflow pulsating frequency and amplitude on the near wall flow characteristics and heat transfer. Results show that due to velocity within boundary layer, wall temperature, surface friction coefficient and average wall heat transfer coefficient are periodically changed. Phase difference is found between main flow and bounder layer flow, while a smaller wall distance corresponds to larger phase difference. Velocity amplitude within boundary layer and surface friction coefficient are both in proportion to the inflow velocity amplitude and frequency. Wall temperature and average wall heat transfer coefficient are in direct proportion to the inflow velocity amplitude, but inversely proportional to frequency. When the inflow velocity amplitude and frequency increase large enough, backflow occurs near the wall, and bigger frequency and amplitude means a stronger back flow.
出处
《科学技术与工程》
北大核心
2013年第13期3670-3675,共6页
Science Technology and Engineering
关键词
层流脉动流
平板壁面
边界层流动
laminar pulsating flow flat plate boundary layer flow
