空調區間流場與濃度場之數值分析

Numerical Analysis of Flow Field and Concentration Field in an Air-Conditioning Enclosure

張旻光(Min-Kuang Chang)

指導教授 ： 林誠興博士

元智大學/工程學院/機械工程學系/碩士(1997年)

摘要

隨著工商社會之快速腳步，空調區間內已成為現代人類主要之生活場所。由於空調空間中有許多污染物的產生源，會隨著對流或擴散運動散佈四周，使空調空間內的空氣品質變得較差，甚至會危害人體的健康及降低工作人員的工作效率造成產能的損失，因此空調設備就扮演著室內通風及污染物移除的重要地位。空氣流動的型態相當複雜，流體的對流行為又有自然對流、強制對流、混合對流等方式，加上所模擬室內空調其流場特性大部分是屬於矩形區間強制對流，其流場型態大部分是處於紊流流場，於是對於區間內空氣流動的特性將非常難直接用經驗做出正確的判斷。本文主要是利用PHOENICS套裝軟體來分析限定區間內的流場結構，並規劃出三個模型來分別討論。希望藉由不同的進風口、出風口的位置、速度、壁面溫度、紊流強度、污染源位置等參數，來探討這些參數的改變對於室內空氣品質與污染物移除效率之影響。

關鍵字

自然對流 ； 強制對流 ； 室內空氣品質 ； 污染物移除效率

並列摘要

People are now more interested in improving their living conditions as we enter the post-industrial revolution. Indoor Air-conditioning has played an important factor in improving the quality of life. Concentration levels of indoor pollutants are sometimes higher than the levels of urban air. It could harm our health, which causes a decrease in worker’s efficiency and production. Therefore, air-conditioning plays an important role in removal of pollutants and ventilation. This thesis performs a numerical study of three models: the first is a transient removal of pollutants from a slot-ventilated enclosure with inlet and outlet, the second is steady state removal of contaminant generated by a discrete source in a slot ventilated enclosure, and the other is natural convection in a difference wall temperature three dimensional enclosure. The evolution of the flow field is numerically simulated using low Re number turbulent model. Major parameters of the flow field are calculated and their impacts on the efficiency of contaminant removal are addressed.

並列關鍵字

natural convection ； force convection ； indoor air quality ； efficiency of contaminant removal

參考文獻

【21】趙中興，"計算流體力學模擬軟體應用在室內空氣流動、空氣品質、溫度調節與有毒氣體擴散等分析上的發展與前景(下)"，中國冷凍空調雜誌，Vol.8，pp95~105 (1993).

【27】胡石歐"冷凍庫氣流模擬研究"，中國冷凍空調雜誌，Vol.14，pp95~102 (1994).

【3】林誠興，陳漢興，蕭堅彬，"具隔版效應之傾斜密閉區間內自然對流現象數值模擬分析"，第18屆全國力學會議，1994。

【4】D. E. Cormack, L. G. Leal, and Imberger, "Natural Convection in a shallow Cavity with Differentially HeatedEnds walls. Part l. Asymptotic Theory", Journal of Fluid Mechanics, Vol.65, pp.209-229 (1974)

【5】K. Hanjalic, S. Vasic, "Computation of turbulent natural convection in rectangular enclosures with an algebraic flux model", Int. J. of Heat and Mass Transfer Vol.36, No, 14, pp. 3603-3624 (1993)