熱風循環烘箱熱傳特性研究

本文主要籍由基本熱傳遞學，來探討一個三維、紊流、穩態的熱風循環烘箱，其腔內空間均溫性的數值模擬。其中紊流模式採用標準k-ε模型。數值計算主要分為兩部分，第一部分為模型物理幾何參數不變，改變烘箱元件之參數，如電熱器瓦數、風扇流量及隔熱材k值，第二部分為改變模型物理幾何參數，如熱風入口板上的數量及位置、隔熱材的厚度。熱風循環烘箱主要運作方式為烘箱內有一風扇，其主要將電熱器室內之工作流體送至濾棉（HEPA）過濾整流後，再經由沖孔板上之孔洞送至烘箱物件烘烤區，最後再回到電熱器室內再被風扇所吸入排出，以完成一整個熱風循環。第一部分研究結果顯示烘箱物件烘烤區之平均溫度隨著電熱器瓦數的增加而提高，而風扇流量增加及隔熱材k值的增大，都會使得烘箱物件烘烤區之平均溫度下降。第二部分研究結果可發現到對於此機台沖孔板上較合適的數量為48個，此時烘箱物件烘烤區之平均溫度為所需求的範圍內；而孔洞位置的分布，從結果可看出不適合於沖孔板上半部之位置開洞，以避免工作流體溫度過高；從隔熱材厚度來看，越厚越能使得烘箱物件烘烤區內之能量較不容易散失出去，故可以令我們將電熱器瓦數降低，已達到節能之目的。

關鍵字

熱風循環烘箱；均溫性；標準k-ε模型

並列摘要

The flow and heat transfer characteristics of a hot recirculating oven are studied. Three-dimensional, steady, turbulent flow is simulated using a k-εmodel to study the temperature distribution with the chamber of the oven. The numerical results can be divided into two parts. For the first part, the geometry parameters of the model are fixed and we change the conditions of the component of the oven. For example, power of electric heater, flow rate of fan and thermal conductivity of insulator. In the second part, we change the geometry parameters of the model and the conditions of the component of the oven are fixed. For example, change the hole numbers or position of a plate and the thickness of insulator. Results show that the mean temperature of chamber of the oven are raised by increasing power of the electric heater. When the flow rate of the fan or the thermal conductivity of the insulator are increased, the mean temperature of chamber is decreased. For the second part, we find that the 48 holes on the plate are suitable for the oven, and the mean temperature of the chamber reach the target value. The inlet holes should not be placed in the upper part of the inlet plate. Because this would increase the mean temperature of the chamber to higher than the target value. Using thicker insulation reduces the hat loss, and thus increases the mean temperature and saves energy input.

並列關鍵字

hot recirculating oven ； uniform temperature ； k-ε model

參考文獻

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熱風循環烘箱熱傳特性研究

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