本文旨在運用雙孔徑毛細結構增強迴路式熱管之熱傳性能。文中採用兩種不同粒徑的同種粉末,實際製造出具備兩種孔徑毛細結構,包括雙層型及混粉型。藉以增加更多而有效之蒸氣產生區域進而提昇整體迴路式熱管之性能。文中並同時製作出單孔徑毛細結構以利比較,最後將其分別置入迴路式熱管系統中,測試其性能表現,包括其熱傳能力和熱阻。 在毛細結構製作上,燒結程序中,歷經繁覆的試驗程序,找出各不同粉徑毛細結構與燒結成形溫度的關係,據此並獲得雙孔徑燒結的最佳燒結建議,成功製作完成雙孔徑毛細結構。在毛細結構的性能上,孔隙度在相近的狀態下,雙粉燒結之1:1混粉型式滲透度比單孔徑毛細結構可提升約30%。 綜整實驗結果,比較單粉鬆裝燒結和選用雙粉鬆裝燒結所製作出來的雙孔徑毛細結構之熱性能測試。發現此兩種型式之雙孔徑毛細結構在高瓦數時,達到穩態的時間較單孔徑毛細結構為短,顯示雙孔徑毛細結構較單孔徑毛細結構擁有較佳的液汽分布以便能快速地達到穩態。在同樣設定操作溫度80℃下,單孔徑毛細結構表現出之最佳性能為200W,熱阻為0.26℃/W;選用雙粉鬆裝燒結所製作出的毛細結構,在混粉型式重量比例達1:1時,可達到最大瓦數為300W,熱阻為0.17℃/W。初步量測結果顯示,具雙孔徑毛細結構之迴路式熱管在熱傳性能的提升方面,頗有相當之潛力。
In this paper, bidisperse wick structures were manufactured for enhancing the heat transfer capabilities of the loop heat pipe. Use two particle sizes of the same material to manufacture two types of the bidisperse wick structures, called “the two layers” and “the powders mixed” for increasing more effective vapor region to promote the performance of the loop heat pipe. In the meanwhile, the monodisperse wick structure is manufactured for a contrast. Both of the monodisperse and the bidisperse wick structures were then installed into the loop heat pipe, then the heat transfer performance of the loop heat pipe system was tested. Find the relationship among the different particle sizes with the temperature of the forming wick structures by many times of sintering experiment. Based on the relationship, acquire a proposal of manufacturing bidisperse wick structures successfully. In the wick structure’s parameters, the permeability of “the powders mixed” is enhancing 30% by the monodisperse wick structure when the ratio of the two types of the powders is 1:1 , meanwhile, the porosity of the bidisperse wick structure is close to the one of the monodisperse wick structure. Summing up the tested results of the loop heat pipe with the bidisperse and with the monodisperse wick structures, the two types of the bidisperse wick structures have a shorter time of reaching steady state than the time of the monodisperse structure. Indicating the bidisperse structures improves the vapor and liquid distribution in the porous media when vaporization phenomena occur in it. Series of testing results showed that the maximum heat transport capacity of the loop heat pipe with monodisperse structure was up to 200-Watts and the thermal resistance was 0.26℃/W , meanwhile , the one with bidisperse structure of “the powders mixed” by the ratio is 1:1 was up to 300-Watts and the thermal resistance was 0.17℃/W at 80℃ allowable temperature.On the preliminary measuring, the loop heat pipe with bidisperse wick structures is referred to have high potential for the application.