氣冷式冷卻背心內襯流道流場與熱傳現象之探討

織物的透氣與散熱特性對人體的舒適度有極大的影響，若人體長期處於高溫環境下工作，可能使體內熱調節機制失調，甚至出現熱衰竭(Heat Exhaustion)、熱中暑(Heat Stroke)等症狀。所以在過熱工作環境下，如何有效提升織物散熱效果，以達成人體溫度良好控制是值得探討的問題。目前已有戶外與熱環境工作者穿著氣冷背心(Air-cooling Vest)以提高織物對人體的散熱，本研究針對財團法人紡織產業綜合研究所設計的氣冷式冷卻背心，應用計算流體力(Computational Fluid Dynamics, CFD)商業軟體ANSYS FluentR考慮三維、穩態、不可壓縮紊流及k-ε紊流理論模式之質量、動量、能量統御方程式以模擬內襯流道氣流流動及熱傳現象。此外，本研究將模擬預測流道出口中心軸向速度結果與實驗結果做比對，以驗證模擬結果的準確性，並探究內襯流道的複雜流場和熱傳特性。模擬結果指出，與氣流流動同方向的出口設計，由於具有相對較低的流動阻力，故可產生更高的流道內速度，並達到更好的空氣冷卻效果。除此之外，我們以不同的出口設計、進氣速度和環境溫度做為研究參數，預測在各種變化情形下對氣冷式冷卻背心內表面熱對流係數分佈的影響。

關鍵字

氣冷式冷卻背心；計算流體力學；對流熱傳遞係數

並列摘要

The effects of fabric’s ventilation and cooling are important to human comfort in design of clothes. Persons in a high-temperature environment can cause imbalance of thermoregulation, and in turn result in the symptoms of heat exhaustion and heat stroke. This research aims to achieve cooling enhancement by wearing air-cooling vests as the effective measures for proper control of human thermoregulation in hot environs. In this study, Taiwan Textile Research Institute devised a new air-cooling vest featured with seven internal flow channels. The computational fluid dynamics (CFD) software ANSYS/FluentR was applied using the three-dimensional conservation equations of mass, momentum and energy to simulate the airflow and heat transfer phenomena within the internal channels. The incompressible turbulent flow was also treated with a standard k-ε two-equation model for turbulence closure. We compared the predicted steady axial velocities at the centers of channel exits with the measured data for software validation. The simulated results were employed to investigate the complicated flowfield and heat transfer phenomena around internal channels of the air-cooling vest. In practice, the design with the outlet arranged along the airflow direction produces a higher flow rate due to a relatively lower flow resistance, and thereby achieves better air-cooling outcomes. To enhance the cooling performance, simulations were also conducted to examine the influences of channel outlet design, inlet temperature and velocity on the convective heat transfer coefficient distributions over the inner channel surface of the vest.

並列關鍵字

Air-cooling vest ； CFD simulation ； Convective heat transfer coefficient

參考文獻

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氣冷式冷卻背心內襯流道流場與熱傳現象之探討

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