鋼軋延製程前，鋼胚必須再加熱。鋼胚在加熱爐加熱過程中，溫度分佈均勻性會影響後續軋延製程的順暢性及產品品質，因此加熱爐之溫控技術為製程能力提升的關鍵技術。中鋼公司運轉中之加熱爐隨著爐齡增長而面臨改造的需求，為提升加熱爐之效能，急需建立完整加熱爐之溫控核心技術。
本文利用數值方法研究動樑式加熱爐內流場分析和鋼胚的受熱情形，把鋼胚視為一高黏滯係數的流體進行模擬，將鋼胚和爐內高溫氣體進行耦合，進而得到加熱爐內流場分佈、速度場分佈、以及鋼胚溫度分佈。整體三維加熱爐模型包含燃燒噴嘴、靜動樑系統、爐壁厚度、鋼胚等等，全文分成兩個物理模型分別為全尺寸模組和簡化五分之一模組。模擬結果顯示兩個物理模型得到的誤差經比較過後差距不大，全尺寸模組和簡化五分之一模組在第一加熱區、第二加熱區及均溫區鋼胚溫度誤差均小於10%，因此參數分析選用簡化五分之一模組進行探討。
研究參數包含不同燃料流率(0.48kg/s及0.53kg/s)以及改變墊塊(skid button)高度，分別為60mm、90mm及120mm下進行數值運算，進而探討不同參數下對鋼胚溫度均勻性的影響。結果指出鋼胚所吸收的熱能超過90%的熱能來自於熱輻射傳遞，只有少部份來自對流，加熱爐效率約在65%，而鋼胚下表面會有受熱不均勻的情形，主要原因來自於靜動樑輻射遮蔽效應，另一原因為冷卻系統也會藉由墊塊從鋼胚下表面帶走熱量而讓該接觸點產生溫度最低點，這種鋼胚上下表面溫度不均勻現象稱為冷痕(skid mark)。結果顯示在墊塊高度120mm、90mm和60mm下，鋼胚上下表面溫度最大差距依序為70.4K、81.2K和105K，此乃因墊塊高度增加，會降低輻射遮蔽效應，使得冷痕現象獲得改善。此外，當入口流率增加為0.53kg/s時，爐溫和鋼胚溫度因為流率增加而提高，冷痕溫度為70K，而當流率為0.48kg/s時，冷痕溫度為81.4K，鋼胚的溫度均勻性也會有所提升。

This thesis numerically analyzed the flow field in the walking-beam-type reheating furnace and heat transfer in the slab. The slab is modeled as a laminar flow having a high viscosity. The temperature distributions of the slab and velocity distributions of the gas mixture are obtained through a coupled calculation. The geometric model takes care of all components of the furnace, including the burners, the walking-beam systems, furnace thickness, slab, and so on. There are two physical models considered in this study: full-scale module and simplified one-fifth module. For both models, the numerical predictions of the slab temperature error are less than 10 %compared with those of experimental data. The numerical results showed the radiation heat transfer dominates the heating process in the combustion furnace; it is around 90% of total input heating energy only few by convection. The furnace efficiency is about 65%. The temperatures of the slab on the upper surface are higher than those at lower surface due to the shield effect by the walking beams. Furthermore, the results also revealed when the skid button height is 60mm, 90mm, 120mm, respectively, the slab largest temperature difference is 70.4K, 81.2K, 105K. It means the slab skid mark can be improved by increasing the height of the skid button. Furthermore, when the fuel inlet flow rate from is increased from 0.48 kg/s to 0.53kg/s, the skid mark temperature difference is decreased from 81.2K to 70K.

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