- 學位論文
雙氣簾展示櫃中內、外出風口風速影響冷卻效應之數值研究
Numerical Study on the Cooling Effect of Different Inner and Outer jet Velocities for Display Cabinet with Double Air Curtains
摘要
本研究針對直立型開放式雙氣簾展示櫃進行電腦模擬分析，在固定內氣簾風速並調整不同外氣簾風速下，分成五種案例來加以分析比較，其分別為內（外）氣簾風速0.3m/s（0 m/s ~1.5 m/s）、0.6 m/s（0 m/s~1.5 m/s）、0.9 m/s（0 m/s~1.5 m/s）、1.2 m/s（0 m/s~1.5 m/s）、1.5 m/s（0 m/s~1.5 m/s），並利用展示櫃溫度指標、冷風洩漏量、冷卻能力、性能指標之方法來了解此展示櫃最佳化設計參數之效應。本文運用以有限體積法的套裝軟體PHOENICS來計算，採用Standard k-ε紊流模式來模擬展示櫃二維穩態之流場，根據上述研究方法及多次的模擬結果發現： 1. 在所有案例中，單氣簾展示櫃（亦即外氣簾風速0m/s）其冷卻能力以及性能均比雙 氣簾還要來的差。 2. 在5種不同的內氣簾風速案例中，對展示櫃內溫度分佈與展示櫃整體耗能而言，其最佳 的搭配分別為內（外）氣簾0.3 m/s（0.3 m/s）、0.6 m/s（0.5 m/s）、0.9 m/s （0.7 m/s）、1.2（0.7m/s）、1.5（0.9 m/s）。其平均溫度分別為6.5℃、4.2℃、 3.2℃、3.0℃、2.5℃，而耗能分別為444 W/m、648 W/m、780 W/m、910.4 W/m、 1064.6W/m。 3. 對冷卻效果而言，最佳搭配的內（外）氣簾風速為0.3 m/s（1.5m/s）、0.6 m/s （1.5 m/s）、0.9 m/s（1.5 m/s）、1.2 m/s（1.5 m/s）、1.5 m/s（1.5m/s），其冷 卻效果的值分別為2964 W/m、4666W/m、6229 W/m、7790 W/m、9398 W/m。 4. 對冷卻值而言，其代表穩態時整體展示櫃內的冷卻能力，此值大代表瞬間冷卻效果 佳，但立刻會造成溫昇。
並列摘要
This research focuses on the numerical simulation of an open type vertical display cabinet with double air curtains. The velocities of inner and outer air curtains are separately divided into five conditions for comparison and those are 0.3m/s, 0.6 m/s, 0.9 m/s, 1.2 m/s, and 1.5 m/s. This work introduces the temperature index of display cabinet, cold air leakage, cooling capacity, and CPI (cabinet performance index) to check the effect of this display cabinet and then to find its optimum operating conditions. The software package of PHOENICS was used to simulate the flow field of this 2-D display cabinet. Standard k-ε turbulence model was used in simulation. According to the foregoing method and numerous simulate results, here can find 1. In all situations, the cooling capacity and function of the display cabinet due to single air curtain is worse than that of double air curtains. 2. Considering the temperature distribution of the display cabinet and total energy consumption in all five types of situations, the best collocations of velocity on inner(outer) air curtain are set as 0.3 m/s(0.3 m/s), 0.6 m/s(0.5 m/s), 0.9 m/s(0.7 m/s), 1.2(0.7m/s), and 1.5(0.9m/s), respectively, where the average temperature of display cabinet can be keep on 6.5℃、4.2℃、3.2℃、3.0℃、2.5℃, and the energy consumption are 444 W/m, 648 W/m, 780 W/m, 910.4 W/m, and 1064.6 W/m, respectively. 3. Focusing on the cooling effect, the best collocation between inner and outer curtain velocity are 0.3 m/s(1.5m/s), 0.6 m/s(1.5 m/s), 0.9 m/s(1.5 m/s), 1.2 m/s(1.5 m/s), 1.5 m/s(1.5m/s), where the value of cooling effect are 2964 W/m, 4666 W/m, 6229 W/m, 7790 W/m, 9398 W/m, respectively. 4. For the magnitude of cooling capacity, it only represents the cooling capability of the whole display cabinet in steady state. The larger value it is, the great cooling effect would be get. However, it will also cause the temperature raising immediately.