防颱百葉之三維流場模擬與性能分析

A study of Three Dimensional Flow Field Simulation and Performance Analysis on Storm-Resistant Louver

鄭晏弦(Yan-Shian Jeng)

指導教授 ： 簡良翰

國立臺北科技大學/機電學院/冷凍空調工程系所/碩士(2010年)

https://doi.org/10.6841/NTUT.2010.00551

摘要

本研究探討防颱百葉於各種不同外氣風速、雨量與送風量條件下之性能及流場結構。利用計算流體力學分析軟體(Fluent)以模擬防颱百葉單一流道在穩態、三維、假設不可壓縮的工作流體條件下的流場特性，研究在不同風速下阻雨葉片、百葉間距對阻雨性能及風壓之影響。經實驗量測數據比較，驗證本研究提出之模擬所得之壓降數據正確、流場結構合理。模擬主要是由六面體網格網格所組成的正交網格，採用有限體積法離散控制方程式，以SIMPLEC法耦合速度和壓力以求解統禦方程式，並以κ-ε紊流模式配合體積分率法處理三維流場。模擬雨滴流動軌跡及阻雨率分析時，進雨量設定為76mm/h，使用離散相（DPM）進行模擬。模擬結果發現阻雨葉片可影響內部流場分佈，而其擺置位置與渦流產生及壓降的增加有密切關係；液滴因流動路徑的改變造成因慣性力沿著切線方向撞擊壁面，因此可在彎道壁面處設置阻雨葉片，將撞擊過後的液滴補集使液滴順著阻雨葉片往下流出排水口。過多的阻雨葉片、連續S型彎道設計和流道過於曲折使得流體每流經一流道時，流道截面積大幅變化造成速度變化明顯並產生渦流，最後導致入出口壓差過大。本研究依氣流場模擬結果，改良阻雨葉片與流道的設計，和多阻雨葉片設計的百葉有一樣的阻雨效率，卻可達到更低壓損、更大流道收縮比的設計目標。

關鍵字

計算流體力學 ； 有限體積法有 ； DPM

並列摘要

This study investigates the storm-resistant louver in a variety of outside air wind speed, rainfall and air flow conditions of the performance and flow field structure. Computational fluid dynamics software (Fluent) was used to simulate a three dimensional channel of storm-resistant louver in steady state, assuming incompressible fluid. Water penetration effectiveness and pressure performance of various louver and drainable blade parameters were investigated for different air velocity. The numerical simulation was verified by experimental data of pressure drops, and reasonable flow field structure. Finite volume method with hexahedron grids were used in discretizing the governingcontrol equations, and solved with SIMPLEC algorithm and the κ-ε turbulent model. The discrete phase model (DPM) was used in the simulation of raindrop flowing path and water penetration effectiveness analysis, and rainfall rate of 76mm/h was assumed. The simulation result revealed that drainable blade can affect the internal flow field distribution, inappropriate position of the blade results in vortexes generation, which increases the pressure drop. Because the droplets flow route change make it due to inertia force along the tangent hit the wall surface,therefore may set The simulation showed that the drainable blade shoud be located at the extruding curve to prevent the raindrops passed the curve tangentially by inertia force. Number of curves should be reduced to reduce pressure drop. Number of the drainable blades is as important as the position of the blade. The flow channel cross-section should be as smooth as possible and prevent sharp variation of cross-sectional area which would generate vortexes and increase pressure drop. From a series of simulations, an improved storm resistant louver was proposed. It has better water penetration effectiveness, lower pressure drop, and greater channel contraction ratio.

並列關鍵字

Computational Fluid Dynamics ； TheFinite Volume Method ； DPM

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