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数值研究了热压自然通风作用下太阳能烟囱的回流特性,采用流线和热线实现烟囱内空气流动和热量传递的可视化,并探讨了玻璃侧离散热源空间位置和热源尺寸等因素对回流过程的影响.当吸热壁面热源强度即热瑞利数Rayleigh(Ra)超过104,烟囱出口处开始出现回流;随着Ra数增大,烟囱回流穿透深度增加.分析表明,左侧热源个数及高度分别为N=1、D_0=1时,其与底部距离S_0以1的步长向上移动,均能有效地避免出口处的回流,其中S_0=0诱导的无因次体积流量最大.而在热源高度D_0=D_1=0.5、N=2、S_0=0时,在与D_0的距离S_1与N=1中S_0(S_0>0)的值相等时,N=2诱导的空气量均大于N=1时诱导的空气量.该研究将有利于提升未来低能耗建筑自然通风的利用效率.
The recirculation characteristics of the solar chimney under the effect of heat and pressure natural ventilation are numerically investigated. The flow and heat transfer of the chimney are visualized by using the flow line and the hotline. The influence of spatial location and heat source size of the glass-side heat source on the reflux process is also discussed .When the intensity of the heat-absorbing wall heat source, ie, the Rayleigh (Ra) of heat Rayleigh number exceeds 104, reflux occurs at the outlet of the chimney; as the Ra number increases, the depth of the chimney’s backflow penetrates increases. The analysis shows that the number and height of the left heat source Respectively, when N = 1 and D_0 = 1, the distance from the bottom to the bottom of S_0 moves upward by one step, both of which can effectively avoid the backflow at the exit, where the dimensionless volume flow induced by S_0 = 0 is the largest, When the value of S_0 (S_0> 0) is equal to the distance S_1 of D_0 and N = 1, the air quantities induced by N = 2 are all greater than N = 1 when height D_0 = D_1 = 0.5, N = 2 and S_0 = When the amount of air induced by the study will help to improve the efficiency of the natural ventilation of low-energy buildings in the future.