空調區間空氣流動數值模擬

Numerical Simulation of Air Flow in An Air-Conditioned Room

韓親民(Chin - Min Harn)

指導教授 ： 林誠興

元智大學/工程學院/機械工程學系/碩士(1995年)

摘要

隨著時代之進步，室內已成為現代人類主要之生活場所，而空氣流
動方式是影響室內空氣品質、舒適感、健康、安全性及空調設備效率的主
要因素。一般而言，空調區間內空氣流場十分複雜，其流動方式受進口風
速、進口溫度、入射角度、區間內傢具擺設方式、區間內熱源位置及大小
等因素所影響，因此我們有必要提供一工具來計算/預測室內空氣流場的
分佈特性。由經驗明顯知道室內流場通常是處於一十分紊亂的狀態，其空
氣流動方式從層流、過渡流、完全紊流都有可能，除此之外室內空氣和牆
壁之間的熱傳狀態可能是自然對流、混合對流、強制對流之中的任一種，
所以空氣流動特性極難直接由經驗做出正確判斷，在本研究中使用目前最
普遍的雙方程式模式 k－E Model 來計算紊流流場。空調區間空氣流動之
行為特性除應用於室內空調設計外，在能源工程的應用方面，諸如室內空
氣品質控制、溫度調節、有毒氣體擴散、冷凍庫房設計問題、大樓之通風
系統設計、廚房之排煙問題、核子反應爐之熱傳、建築物火災行為中排煙
系統設計分析等等，應用相當廣泛。本研究採用數值模擬方法來分析流場
特性並利用適合模擬室內流場的K-E紊流模式來模擬紊流流場，在數值計
算過程中分別解流場的連續方程式、動量方程式、能量方程式、濃度方程
式、及紊流動能方程式及紊流動能逸散方程式。本研究擬評估進口風速、
進口溫度、壁溫高低、壁溫差、受日照壁面位置等邊界條件對於流場的影
響，其結果將可輔助日後智慧型空調系統開發設計時的參考，另外也將數
值計算所得速度場、溫度場、紊流動能場等數據，經由目前最常使用的舒
適感模式Predicted Mean Vote （PMV）模式和Percentage of
Dissatisfied （PD%）模式來分析舒適程度變化，以提供空調設計時參考
依據,另外由PD(IAQ)模式來預測計算室內空氣品質之良劣。

關鍵字

空氣流場 ； 數值分析 ； 舒適感 ； 空氣品質

並列摘要

Up to 90﹪of a typical person''s daily life is spent indoors
either in a residential or commercial building. Therefore, the
quality of indoor air is increasingly being recognized as an
important factor for overall health and comfort. During the past
decade, indoor air pollution emerged as an international health
issue. Indoor air movement/motion are also an essential
component for thermal comfort ,which in turn would greatly
affect the operation efficiency of air condition systems. Hence,
it is necessary to provide means/tools to compute/predict air
distributions within rooms. Investigations of indoor airflow
pattern ,air quality and thermal comfort will be carried out by
numerical simulations in this research project. It is well known
that turbulence occurs as a chaotic state of air motion in
buildings. It is difficult to identify whether a room airflow is
a transitional airflow ,locally artificially induced turbulent
flow or fully developed turbulent flow. Besides, the convective
heat transfer mode(between air/wall) could be one of the three
modes -natural ,mixed and forced convection. The
characteristics/dynamics of air flow patterns are therefore
extremely complicated. In this project, the commonly used two
equation model,(i.e. ,Low Reynolds k-E model) is used to account
for the airflow turbulence. The continuity ,momentum and energy
and concentration equations are numerically solved to predict
airflow movement. The engineering models for thermal comfort
(PMV/PD)and air quality(PD) will be then incorporated with the
airflow analysis. The important factors affecting the airflow
patterns will be studied in details.

並列關鍵字

Indoor Air Movement ； Numerical Simulation ； Thermal Comfort ； Indoor Air Quality