不同開口對風壓通風量之數值模擬

Numerical Simulation of Wind-driven Ventilation for Buildings with Multiple Openings

陳侃君(Kan-Jun Chen)

指導教授 ： 朱佳仁

國立中央大學/工學院/土木工程學系/碩士(2015年)

摘要

自然通風在建築物設計上是相當重要的課題之一，而窗戶的配置及風向對於風壓通風有著相當重要的影響。本研究採用計算流體動力學模式研究開口的配置對於室外風壓及通風量的影響，並利用積分法及通風模式計算通風量。主要探討的參數為風向角及開口的位置。結果顯示除了兩個開口放置在迎風面，其他的窗口配置會隨著風向角增大導致通風量變小。當窗口的配置導致剪力通風時，通風效果變差，在計算通風量時會有明顯的誤差。另一方面，三個窗口分別配置於建築三面外牆上的流況，利用積分法計算得之通風量遵守質量守恆定律與通風模式預測之值。本研究繪製之壓力分佈圖及速度分佈圖可幫助瞭解空氣在建築物室內室外之流動狀況。

關鍵字

自然通風 ； 風壓通風 ； 大渦模擬 ； 風向角

並列摘要

This study used a three-dimensional Large Eddy Simulation (LES) model to investigate the influences of wind-driven ventilation of a cubic building with multiple openings. Five different configurations of openings are considered with three different wind directions. The ventilation rate Q through the building openings was calculated by two different methods. The first method is to integrate the predicted time-averaged velocities normal to the openings, another method is to substitute the predicted pressure coefficients Cp1 and Cp2 at the openings into a ventilation model. The results indicate that, the ventilation rates predicted by two different methods agree with each other when the openings were on different walls, but have large discrepancy when the openings were on the same wall. For buildings with three openings on three different external walls, the ventilation rates computed by the integration method satisfied the law of mass conservation, and agreed with the values predicted by the ventilation model. The simulated pressure distribution and velocity vectors around and inside the building can help us to understand the ventilation process.

並列關鍵字

Wind-driven cross ventilation ； Computational Fluid Dynamics ； Large Eddy Simulation ； Wind direction

參考文獻

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