- 學位論文
微型迴路式熱管之模擬與製造
Simulation and Manufacturing of The Miniature Loop Heat Pipe
摘要
本文以吾人自行發展的EES人機介面軟體來模擬穩態迴路式熱管的熱傳情形並考慮熱洩漏的情況。吾人藉由軟體模擬所得到的設計參數與熱傳量來發展一微型迴路式熱管，並依照本實驗室熱阻量測標準流程，來進行驗證。 經由實驗結果得知，由軟體模擬所得設計參數而製作出的迴路式熱管在穩態操作上是符合物理現象的。在工作流體為液態氨並量測不同填充率對於系統性能的影響中，得到最佳填充率為80％；並在改變工作流體為R-134a（填充率亦為80%為最佳）時，得知在低熱負載（＜25W）時，系統熱阻值約為0.22℃/W較工作流體為液態氨時的熱阻值0.32℃/W來的低；而當熱負載繼續增加（＞25W）時，以填充液態氨為工作流體的系統，熱阻值為0.27℃/W比填充R-134a的熱阻值0.41℃/W來的低；在不超過蒸發器最大溫度（Max Te）110℃，系統填充液態氨為工作流體的熱負載（50W），比填充R-134a（40W）為工作流體時的熱負載來的高。 本實驗迴路式熱管由測試得知，最小啟動瓦數為5W與Maydanik[41]提到的最小啟動瓦特數相同。由池沸騰（pool boiling）會有大量液體瞬間汽化之現象而產生溫度突降的變化中，吾人得知熱負載＞10W時，突降溫度減緩；熱負載＜10W時，因汽化不足並無溫度突降的情形。因此將10W定為本系統的最佳啟動瓦特數。 最後，由軟體模擬出的最大熱傳量為44W與藉由實驗測試所得到的50W，有約13.6%的誤差。
並列摘要
This article is to describe that the EES software is developed by myself to simulate the heat-conduction situation of steady-state of a miniature loop heat pipe and to consider its heat-leakage condition. I use software simulation to get the design parameter and the heat load to develop a miniature loop heat pipe, and testify it by our laboratory standard process of thermal resistance measure . According to the result of experiment, we know that this loop heat pipe designed by design parameter from software simulation fits the physical phenomenon under stable-circumstance operation. When working fluid is ammonia and we measure the influence of system function by different fill rate，we get the optimal fill rate 80%. Under the circumstance of low heat laod (＜25W), when we change the working fluid to R-134a whose optimal fill rate is also 80%, we know thermal resistance of the LHP is 0.22℃/W which is lower than the thermal resistance of the LHP 0.32℃/W when using ammonia as the working fluid. However, when heat load increases （＞25W), the system of ammonia has the thermal resistance 0.27℃/W which is lower than the thermal resistance 0.41℃/W from the system of R-134a. Without exceeding the Max Temperature of evaporator temperture 110℃, heat load of ammonia system is 50W higher than R-134a system's 40W. From this experiment of loop heat pipe examination, the minimum start-up power is 5W which is as the same as the minimum start-up power mentioned by Maydanik[41]. From the phenomenon that pool boiling and results in lowering the temperature dramatically, we know when heat load is more than 10W, temperature lowers slowly; when heat load is less than 10W, temperature doesn't lower dramatically due to insufficient vaporization. Therefore, we regard 10W as the optimal start-up power in this system. Finally, compared with the maximum heat load of software simulation, 44W with the 50W one from the experiment, there is an approximately 13.6% error.