气体横掠顺排管束流动特性实验研究

Experimental Investigation on Characteristics of Cross Flow Over Inline Tube Bundles

螺旋管式换热器换热系数高且结构紧凑,被用于高温气冷堆蒸汽发生器及中间换热器。这类换热器壳侧为有壁面包围的横掠管束流动,而壁面的存在会对横掠管束流动产生一定影响。本文中采用分裂式热膜测量了不同管距管径比(P/D)和不同雷诺数(Re)下横掠顺排管束流动管间和管后的速度分布。讨论了流动充分发展区域P/D、Re对管间和管后时均速度分布的影响。然后分析了P/D、Re对管间和管后雷诺正应力分布的影响。选取Re=35875的结果,从频谱角度分析了产生不同雷诺正应力分布的原因,并比较了P/D对管间速度频谱的影响。

Helical tube heat exchangers are used for Steam Generators(SGs)and Intermediate Heat Exchangers(IHXs)of High Temperature Gas-cooled Reactor(HTGR)for their high heat transfer coefficient and compactness.Flow pattern in the shell side of these heat exchangers is cross fow over tube bundles with bounded walls.The bounded wall will influence the characteristics of cross flow over tube bundles.In the present investigation,a split hot flm is used to measure the velocity distributions among and after tubes in tube bundles with different pitch to diameter ratio(P/D)and Reynolds number(Re).The influence of P/D and Re on time averaged velocity distributions is discussed.Then,the infuence of P/D and Re on the time averaged Reynolds normal stress distributions are analyzed.The frequency spectrum of time series measured with Re=35875 are used to analyze the time averaged Reynolds normal stress distributions.Finally,the influence of P/D on velocity frequency spectrum is discussed.