本文主要探討高溫不銹鋼板AISI304在受到兩種不同型號之扇形噴嘴衝擊的快速冷卻的情形並進行分析，透過實驗的方式量測溫度等物理量並結合ANSYS中的Fluent模組結合Fortran運算的簡易共軛梯度法程式來進行最佳化理論的計算及分析進而求解出其熱傳係數h值的分佈情形。為了達到鋼材所需的機械性質和高品質的目標，以快速冷卻控制鋼材的相變態藉以提高鋼鐵的機械性質及品質，來增加材料的附加價值以提升在全球市場上的競爭力。
本研究分析扇形噴嘴在不同流量下時以噴嘴噴流衝擊噴束快速冷卻一高溫不銹鋼板，透過鋼板內部熱電偶量測到的溫度變化進而求得出其鋼板表面熱傳係數分佈趨勢及冷卻效果，並藉由流場觀察來分析其扇形噴嘴的流動特性及干涉效應。在研究中透過改變噴嘴流量從2.5(L/min)到8.5(L/min)的範圍內以五組不同流量下量測到的溫度變化來進一步計算出其熱傳效果及冷卻速率，並觀察在不同流量下時的流場變化情形。熱傳係數的計算部分吾人主要透過三維逆向熱傳導的方法來求解，其演算法主要使用了共軛梯度法作為逆向計算方法並透過最佳化方式來計算出其鋼板表面之熱傳係數分佈。共軛梯度法主要是透過疊代的方式來對熱傳導方程式進行逆向計算並在過程中向收斂的方向進行搜尋，在達到設定的目標函數下停止疊代計算的過程以求得出最佳之熱傳係數分佈的趨勢及值級。
實驗系統加熱試件部分主要以一與電熱管一體成形的不銹鋼板作為加熱試件，在實驗噴嘴水供給系統部分主要透過一水循環的管路線並由一泵浦來做為整體水循環的推動裝置。本研究首先針對單噴嘴及雙噴嘴的流場觀察進行分析，在單噴嘴的流場觀察中隨著流量的提升衝擊橢圓區域以及噴嘴寬幅會隨之上升。在雙噴嘴的流場觀測中兩噴嘴在特定的間距下交互作用時會產生干涉的現象，此間距在加熱不銹鋼板冷卻時會在此處形成薄膜沸騰的現象，此現象不僅會影響流場流動情形同時亦會大幅降低熱傳效果。從共軛梯度法逆向計算的結果得到在扇形噴嘴衝擊冷卻高溫不鏽鋼板的表面熱傳係數上，第一種型號噴嘴有相對較好的熱傳效果。當流量Q=2.5、5、7.4(L/min)增加的過程中其整體平均熱傳係數依序從2807.70、4572.23增加至5352.76(W/m2-K)，同時對應之平均冷卻速率分別為4.29、5.42、5.71(°C/s)。同時當兩種型號噴嘴分別達到恰好衝擊加熱不銹鋼板流量範圍時，其平均熱傳係數大約為5000(W/m2-K)的大小對應之平均冷卻速率為5.5 (°C/s)。

This study discusses and investigates the high-temperature stainless steel plate AISI304 through the rapid cooling by two different types flat fan nozzles. Through the experimental measured temperature data and combine the Fluent module in commercial software ANSYS, connecting with the simple conjugate gradient method of Fortran program to calculate and analyze the distribution of heat transfer coefficient h value.
In this study, the flat fan nozzle is used to rapidly cool a high-temperature stainless steel plate with different flow rates. The temperature distribution of the steel plate is measured by the thermocouple inside the steel plate, then the h value distribution and the cooling effect is further obtained. The flow characteristics and interference effects of the nozzles were observed by flow field observation. The heat transfer coefficients for 2 different kind of flat fan nozzles and 5 different flow rates( 2.5L/min to 8 L/min) are calculated by the 3-D inverse heat transfer models solved by an algorithm developed with the conjugate-gradient method. The conjugate gradient method was an iterative method for solving an equation and used to optimize the heat transfer coefficient distribution.
The experimental system is divide into heating part and nozzle water supply part. For the double nozzle, the two nozzles will interfere when they interact at a specific spacing. This spacing will form a film boiling phenomenon when cooling the heated stainless steel plate which heated over the boiling point. This phenomenon will not only affect the flow field flow. The situation will also greatly reduce the heat transfer effect.
From the inverse calculation of the conjugate gradient method, the surface heat transfer coefficient of the flat fan nozzle jet impingement cooling high-temperature stainless steel plate is obtained. The first type of nozzle has a relatively good heat transfer effect. When the flow rate increases from Q=2.5, 5, 7.4 (L/min), the overall average heat transfer coefficient increases from 2807.70, 4572.23 to 5352.76 (W/m2-K) respectively, and the corresponding average cooling rate is 4.29, 5.42, 5.71 (°C/s) respectively. At the same time, when the two types of nozzles respectively reach the flow range of the impact-heated stainless steel plate, the average heat transfer coefficient is about 5000 (W/m2-K) corresponding to an average cooling rate of 5.5 (°C/s).

[1] Martin, H., “Heat and Mass Transfer between Impinging Gas Jets and Solid Surfaces”, Advances in Heat Transfer, Vol. 13, pp. 1-60, 1977.
[2] Stevens, J. and Webb, B., “Local Heat Transfer Coefficients under an Axisymmetric, Single-Phase Liquid Jet”, Journal of Heat Transfer, Vol. 113. No.1, pp. 71-78, 1991.
[3] Liu, X., Lienhard, J. and Lombara, J., “Convective Heat Transfer by Impingement of Circular Liquid Jets”, Journal of Heat Transfer, Vol. 113. No.3, pp. 571-582, 1991.
[4] Garimella, S.V. and Rice, R.A., “Confined and Submerged Liquid Jet Impingement Heat Transfer”, Journal of Heat Transfer, Vol. 117. pp. 871-877, 1995.
[5] Fitzgerald, J. A. and Garimella, S. V., “Flow Field Effects on Heat Transfer in Confined Jet Impingement”, Journal of Heat Transfer, Vol. 119, pp. 630-635, 1997.
[6] Cho, M. J., Thomas, B.G. and Lee, P. J. , “Three Dimensional Numerical Study of Impinging Water Jets in Runout Table Cooling Processes”, Metallurgical and Materials Transactions B, Vol. 39, No. 4, pp. 593-602, 2008.
[7] Passandideh-Fard, M. and Khavari, M., “Numerical Simulation of the Impingement of a Vertical Liquid Jet on a Solid Surface”, 17th Annual(International) Conference in Mechanical Enginnering, 2009.
[8] Son, S., Son, G., Park, L. and Lee, P., “Numerical Study of Flow and Cooling Characteristics of Impinging Liquid Jets on a Moving Plate”, 14th International Heat Transfer Conference, ASME, pp. 555-562, 2010.
[9] Hosain, M. L., Fdhila, R. B., Raudensky, M. and Daneryd, A., “Heat Transfer by Liquid Jets Impinging on a Hot Flat Surface”, Applied Energy, Vol. 164, pp.934-943, 2016.
[10] Liu, Z. D., Feaser, D. and Samarasekera, I. V., “Experimental Study and Calculation of Boiling Heat Transfer on Steel Plates during Runout Table Operation”, Canadian Metallurgical Quarterly, Vol. 41, No. 1, pp. 63-74, 2002.
[11] Júnior, H. L., da Silva, A. F. C. and Passos, J. C., “Analysis of The Cooling Effect of a Water Jet on a Hot Steel Plate”, 19th International Congress of Mechanical Enginnering, 2007.
[12] Wang, H., Yu, W. and Cai, Q.W., “Experimental Study of Heat Transfer Coefficient on Hot Steel Plate during Water Jet Impingement Cooling”, Journal of Materials Processing Technology, Vol. 212, No. 9, pp. 1825-1831, 2012.
[13] 陳詡濙, “爐渣顯熱熱回收與水噴流衝擊冷卻熱液動分析”, 機械工程研究所, 國立成功大學碩士論文, 指導教授：張錦裕, 2017.
[14] 鄭喬鴻, “Spray Droplet Diameter and Flowfield Characteristic Analysis”機械與機電工程研究所, 國立中山大學碩士論文, 指導教授：謝曉星, 2012.
[15] Deiters, T. A. and Mudawar, I., “Optimization of Spray Quenching for Aluminum Extrusion, Forging, or Continuous Casting”, Journal of Heat Treating, Vol. 7, No. 1, pp. 9-18, 1989
[16] Becker, E. U., Birkemeier, G., Buchele, W. Degner, M., Devrient, L. Nowak, M. and Thiemann, G., “Optimization of Descaling Nozzles in a Hot Strip Mill”, Metallurgical Plant and Technology International(Germany), Vol. 23, No. 5, pp. 92-94, 2000
[17] Bendig, L., Raudenský, M. and Horský, J., “Descaling with High Pressure Nozzles”, ILLAS-Europe, pp. 2-6, 2001.
[18] Frick, J. W., “Optimisation of Nozzle Arrangements on Descaling Headers”, 4th International Conference on Hydraulic Descaling, London, 2003.
[19] Horsky, J., Raudenský, M. and Vavrecka, L., “Experimental Study of Heat Transfer in Hot Rolling”, 16th IAS Rolling Conference, 2006.
[20] Karwa, N., Kale, S. R. and Subbarao, P. M. V., “Experimental Study of Non-Boiling Heat Transfer from a Horizontal Surface by Water Sprays”, Experimental Thermal and Fluid Science, Vol. 32, No. 2, pp. 571–579, 2007.
[21] Zuckerman, N. and Lior, N., “Radial Slot Jet Impingement Flow and Heat Transfer on a Cylindrical Target”, Journal of Thermophysics and Heat Transfer, Vol. 21, No. 3, pp. 548–561, 2007
[22] Etemoglu, A. B. et al., “Investigation into the Effect of Nozzle Shape on the Nozzle Discharge Coefficient and Heat and Mass Transfer Characteristics of Impinging Air Jets”, Heat Mass Transfer, Vol.46, No.11-12, pp. 1395-1410, 2010.
[23] Hnizdil, M., Isman, M. K. and Can, M., “Heat Transfer during Spray Cooling of Flat Surfaces with Water at Large Reynolds Numbers”, Journal of Flow Control, Measurement & Visualization, Vol.4, No.3, pp. 104-113, 2016.
[24] Jarny, Y., Ozisik, M. N. and Bardon, J. P., “A General Optimization Method Using Adjoint Equation for Solving Multidimensional Inverse Heat Conduction”, International Journal of Heat and Mass Transfer, Vol.34, No. 11, pp. 2911-2919, 1991.
[25] Huang, C. H. and Wang, S. P., “A Three-Dimensional Inverse Heat Conduction Problem in Estimating Surface Heat Flux by Conjugate Gradient Method”, International Journal of Heat and Mass Transfer, Vol. 42, No. 18, pp. 3387-3403, 1999
[26] Huang, C. H., Hsu, G. C. and Jang, J. Y., “A Nonlinear Inverse Problem for the Prediction of Local Thermal Contact Conductance in Plate Finned-Tube Heat Exchangers”, Heat and Mass Transfer, Vol. 37, No. 4, pp. 351-359, 2001.
[27] Chen, W. L., Yang, Y. C. and Lee, H. L., “Inverse Problem in Determining Convection Heat Transfer Coefficient of an Annular Fin”, Energy Conversion and Management, Vol.48, No. 4, pp. 1081-1088, 2007.
[28] Zhang, J. and Delichatsios, M. A., “Determination of the Convective Heat Transfer Coefficient in Three-Dimensional Inverse Heat Conduction Problems”, Fire Safety Journal, Vol. 44, No. 5, pp. 681-690, 2009.
[29] 中日噴霧股份有限公司，產品介紹，一流體標準扇型噴嘴，檢自http://www.ikeuchi.com.tw/front/bin/ptdetail.phtml?Part=vvp_series&Category=20
[30] Cheng, C. H., and Chang, M. H., “A Simplified Conjugate-Gradient Method for Shape Identification Based on Thermal Data”, Numerical Heat Transfer, Part B, Vol. 43, No. 5, pp. 489-507, 2003.