現代生活水平提昇，汽車也不再只是以往單純的代步工具，更多的功能、更好的品質、更加的舒適性皆為汽車發展的趨勢。本文中將對於車艙內的熱舒適性做研究，以實驗搭配數值計算的方式來得到PMV指標與PPD指標的參數，並計算各乘客的熱舒適性指標與最佳溫度。在實驗方面，實驗車款是Nissan Sentra 2000房車，車艙內空調系統設定在25°C，並分為無乘客時與有乘客時共三個不同的實驗，並在各實驗中對冷氣出風口在不同等級出風量時，做溫度與出風口風速與相對濕度的量測。在數值模擬方面，是採用商用套裝軟體FLUENT，在不考慮化學反應、重力及輻射熱傳下，以SST(Shear-Stress Transport) K-ω紊流模式，並將實驗量測到的邊界溫度與出風口風速代入做計算求解車艙內的流場與溫度場，再將計算的溫度場與各量測點量到的溫度做比對，以驗證模擬的正確性。最後便可由模擬的車艙內流場得到的相對風速，搭配實驗量到的相對濕度，進而求出PMV指標與PPD指標與最佳溫度。由模擬結果得知，每組模擬與實驗的溫度平均誤差階小於3°C。結果顯示空車時模擬非穩態的溫度對時間變化與實際量測的大致相符合。而在熱舒適性評估方面，從有駕駛員的實驗與數值模擬結果可以發現，當出風口向下吹時，所預測的最佳溫度最高，而出風口向上吹時，所預測的最佳溫度最低；在有四位乘客的實驗與數值模擬中可以發現，坐在前座乘客座的人所需的最佳溫度會較其他三人高約0.2至0.8°C。

With the increase of living standard nowadays, automobiles are not only a mean of transportation tool but also equipped more capability functions, better quality and much comfort. In this study, by using experiment and numerical simulation, thermal comfort for passengers in an air-conditioned automobile cabin is numerically investigated with a PMV indicator and a PPD indicator for finding a best temperature. For the experiment part, the model of an experimental car used is a car of Nissan Sentra 2000. The air conditioning system in the cabin was set at 25°C. There were three different cases of experiments: empty car, a driver in the cabin, and four passengers in the cabin. In each case, temperature, wind velocity at the fan and relative humidity were measured in different fan levels. In the numerical simulation part, the commercial software FLUENT were used. Without regard to chemical reaction, gravity and radiant heat transfer, the boundary temperature and the wind velocity at fan measured by experiment were the inputs for calculation in the K-ω turbulent model. For code validation, the temperatures calculated by numerical simulation were compared with these for experiment. Finally, the air velocity found by numerical simulation and the relative humidity measured by experiment, we can find the values of the PMV indicator, PPD indicator, and best temperature. From our simulation results, computed temperature distribution for each case is compared well with that in experiment, and their difference measured by mean error is less than 3°C. The computed and experimental temperatures in unsteady case are very close for the case of empty car. For the evaluation of thermal comfort, it is found that for the case of upward-direction fan, the predicted best temperature is the highest. But, for the case of downward-direction fan, the predicted best temperature is the lowest. For the case of four passengers seated in the cabin, the best temperature for man who seated in passenger’s seat is slight higher (0.2 to 0.8°C) than others.

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