Abstract
近來煉鋼業中, 連續鑄造因有節省能源, 生產速度快,品質穩定等優點,已成為重要的生產方法. 因此有許多人努力於此方面的研究. 本文是利用數值方法來模擬鋼鐵連續鑄造過程中的溫度場, 壓力場和速度場.以往研究此方面的問題, 在實驗方面困難太多, 無法真正量測液態區內的速度和溫度. 而在數值方面又因數質方法的限制, 必需對問題做不合理的假設,所以無法充份瞭解液態區內的重要現象.本文共分為七章. 第一章前言;第二章文獻回顧; 第三章問題選擇; 第四章數學分析; 第五章解題方法;第六章結果與討論; 第七章結論.在本計算中考慮由進料噴嘴產生的強制對流的影響. 所採用的方法, 以 APPLE algorithm 計算速度和壓力場.以新發展的潛熱法計算溫度場. 因採用新的單區法, 所有計算均在直角座標中完成而不需經座標轉換或網格產生.配合 Modified W.F.S. 以及SIS 使的數值收斂快而精準.文中對鋼板的不同抽拉速度和噴嘴寬度作計算並和假設無流場的狀況比較. 由計算結果顯示, 連續鑄造製程中進料噴嘴對液固界面的形狀無太大的影響, 但對液態區內的溫度梯度影響很大.這項結果顯示噴嘴所造成的強制對流可加大液固界面附近的溫度梯度, 以抑制等軸晶的成長,可以改善產品的機械性質.To simulate a continuous casting process the temperature andflow field during solidification of steel in a moving slab isconsidered. The analysis includes forced convection effects inthe liquid pool. In the present investigation, the APPLEalgorithm and the modified weighting function scheme areapplied to the solidication process of the continuous casting.All of the computations are performed on a Cartesian coordinatesystem without recourse to coordinate transformation or gridgeneration for the shape of the solidification interface. Inconjunction with an enthaopy formulation, solutions of thecoupled mass continuity, momentum and energy have beenobtained. The effects of withdrawal velocity and the size ofnozzle were investigated and compared with that from slug flow.The present numerical technique produces smooth streamlines,isobars and isotherms even in the vicinity of thesolidification interface. The results reveals that near thebottom of the pool, the jet seems to result in a temperaturegradient higher than it's counter part in case of slug flow.