Correlations for forced convective heat transfer coefficients at the windward building façade with vertical louvers
Correlations for forced convective heat transfer coefficients at the windward building façade with vertical louvers
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DOI：
10.1016/j.buildenv.2023.110611
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发表时间：
2023-08
影响因子：
7.4
通讯作者：
Shi Tao;Nanyang Yu;Fujian Jiang;Xiaowen Su;K. Zhao
中科院分区：
文献类型：
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作者：
Shi Tao;Nanyang Yu;Fujian Jiang;Xiaowen Su;K. Zhao
垂直百叶窗是一种广泛使用的外遮阳系统，用于控制建筑物的自然采光和太阳能得热。然而，当安装在建筑物立面上时，它们会扰乱立面周围的流场，影响建筑物外表面的外部对流传热过程。基于k-ωSST模型对垂直百叶窗-立面系统的强迫对流换热进行了CFD模拟，并进行了详细的验证。采用扩展的牛顿冷却方程描述百叶窗、建筑立面和空气之间的热交换过程，产生四个传热系数：hwa、hba、hbw。研究了无因次温差（θ）、倾角（φ）、百叶窗宽度（B）和安装距离（W）对换热系数的影响。结果表明，θ对平均传热系数影响不大，当φ= 75 °时，hwa达到最小值，h接近最大值。B值从0.3 m增加到1 m时，hwa增加55.3%，hbad减少21.9%。当W从0.25 m增加到1 m时，hw减小5.6%，hba增大39.6%。还解释了百叶窗和建筑立面之间的传热系数（hwbandhbw）的变化。最后，建立了新的成对传热系数的关联式作为φ，B，W和风速（U 10）的函数。这些相关性的准确性进行评估，通过比较计算值与模拟结果。
Vertical louvers are a widely used external shading system to control natural lighting and solar heat gain for buildings. However, when installed on a building façade, they can disrupt the flow field around the façade and affect the external convective heat transfer process of building's exterior surfaces. To this end, this paper conducted CFD simulations to clarify the forced convective heat transfer patterns in a vertical louver-facade system based on thek-ωSST model with a detailed verification. The extended Newton's cooling equation is used to describe the heat exchange process between louvers, building façade, and air, which generates four heat transfer coefficients:hwa,hwb,hba,andhbw. Then the impacts of dimensionless temperature difference (θ), louver angle (φ), louver slat width (B), and installation distance (W) on the heat transfer coefficients are investigated. The results show thatθdoes not affect the average heat transfer coefficients.hwareaches a minimum value andhbareaches a maximum value whenφ= 75o. In addition,hwaincreases by 55.3% andhbadecreases by 21.9% asBincreases from 0.3 m to 1 m. WhenWincreases from 0.25 m to 1 m,hwadecreases by 5.6% andhbaincreases by 39.6%. The variation in the heat transfer coefficients (hwbandhbw) between the louvers and building façade is also explained. Finally, new correlations of paired heat transfer coefficients are established as a function ofφ,B,W, and wind velocity (U10). The accuracy of these correlations is evaluated by comparing calculated values with simulated results.