科技日新月異，處處充滿在我們的生活四周，人們使用電子產品的機會也日漸增多，而公司必須要生產更多電子產品，趕上人們汰換的速度，必須不斷地開發許多技術。
本實驗主要探討孔徑為1.6 mm的二流體噴嘴，經由改變不同的實驗參數，如噴霧高度(H= 40 mm、50 mm、60 mm)、空氣液體質量比(R= 0.145、0.194、0.242、0.259、0.323)及表面溫度(Tw= 25 oC、75 oC、125 oC)，觀察流場及溫度場的變化。
實驗中，加熱系統由銅塊及加熱棒組成，以去離子水做為工作流體，利用微質點影像測速儀 (μPIV) 觀察速度分佈及全像干涉粒徑分析儀 (IPI) 觀察液滴粒徑等流場現象；溫度場量測，使用熱電偶(K-Type)進行冷卻實驗，並透過計算、分析以獲得最佳的臨界熱通量 (Critical Heat flux)。
實驗結果顯示，最佳臨界熱通量及最小的粒徑皆發生在噴霧高度為50 mm、氣液比為0.242。

This experiment mainly discusses the twin-fluid nozzle with the diameter of 1.6 mm by changing different experimental parameters, such as the spray height (H=40 mm, 50 mm, 60 mm), the mass ratio of air to liquid (R = 0.145, 0.194, 0.242, 0.259 , 0.323) and the surface temperature (Tw = 25 oC, 75 oC, 125 oC) to observe the flow field and temperature field.
In the experiment, the heater system consisted of the copper block and heating rods, DI water is used as the working fluid. The velocity distribution is observed by μPIV and the dimension of the particle is observed by IPI; the temperature field measurements, using the thermocouple (K-Type) for the cooling experiment, calculate and analysis to obtain the optimal critical heat flux (CHF).
The experimental results show the optimal critical heat flux and the smallest particle size occurs when the spray height of 50 mm and the gas-liquid ratio of 0.242.

[致謝+i]
[中文摘要+ii]
[ABSTRACT+iii]
[TABLE OF CONTENTS+iv]
[LIST OF TABLES+vi]
[LIST OF FIGURES+vii]
[NOMENCLATURE+ix]
[CHAPTER 1 INTRODUCTION+1]
[1.1 Motivation and background+1]
[1.2 Research purposes+2]
[1.3 Literature review+2]
[CHAPTER 2 EXPERIMENTAL SETUP+17]
[2.1 Optical measurement system+17]
[2.2 Fluid circulation system+19]
[2.3 Heater system+20]
[2.4 Data acquisition system+21]
[2.5 Other equipment+21]
[CHAPTER 3 EXPERIMENTAL PROCEDURE+33]
[3.1 Fluid circulation system+33]
[3.2 Optical measurement system+34]
[3.3 Temperature measurement system+36]
[CHAPTER 4 THEORETICAL ANALYSIS+41]
[4.1 Air to liquid ratio (R)+41]
[4.2 Slip ratio (S)+41]
[4.3 Void fraction (α)+41]
[4.4 Reynolds number (Re)+42]
[4.5 Weber number (We)+42]
[4.6 Heat flux (q")+43]
[4.7 Heat transfer coefficient (h)+43]
[CHAPTER 5 UNCERTAINTY ANALYSIS+45]
[CHAPTER 6 RESULTS AND DISCUSSION+48]
[6.1 μPIV measurements+48]
[6.2 IPI measurements+51]
[6.3 The cooling measurements+52]
[CHAPTER 7 CONCLUSIONS AND RECOMMENDATIONS+83]
[7.1 Conclusions+83]
[7.2 Recommendations+84]
[REFERENCES+85]
[APPENDIX A+90]

[1] R. Kong and S. Kim, "Characterization of horizontal air–water two-phase flow," Nuclear Engineering and Design, vol. 312, 2017, pp. 266-276.
[2] M. Ghodbane and J. Holman, "Experimental study of spray cooling with Freon-113," International Journal of Heat and Mass Transfer, vol. 34, 1991, pp. 1163-1174.
[3] K. A. Estes and I. Mudawar, "Correlation of sauter mean diameter and critical heat flux for spray cooling of small surfaces," International Journal of Heat and Mass Transfer, vol. 38, 1995, pp. 2985-2996.
[4] J. Yang, L. Chow, and M. Pais, "Nucleate boiling heat transfer in spray cooling," Journal of Heat Transfer, vol. 118, 1996, pp. 668-671.
[5] J. D. Bernardin, C. J. Stebbins, and I. Mudawar, "Mapping Of Impact And Heat Transfer Regimes Of Water Drops Impinging On A Polished Surface," International Journal of Heat and Mass Transfer, vol. 40, 1997, pp. 247-267.
[6] K. Oliphant, B. W. Webb, and M. Q. McQuay, "An Experimental Comparison of Liquid Jet Array And Spray Impingement Cooling In The Non-Boiling Regime," Experimental Thermal and Fluid Science, vol. 18, 1998, pp. 1-10.
[7] J. Bernardin and I. Mudawar, "The Leidenfrost point: experimental study and assessment of existing models," Transactions-American Society of Mechanical Engineers Journal of Heat Transfer, vol. 121, 1999, pp. 894-903.
[8] R.-H. Chen, L. C. Chow, and J. E. Navedo, "Effects of spray characteristics on critical heat flux in subcooled water spray cooling," International Journal of Heat and Mass Transfer, vol. 45, 2002, pp. 4033-4043.
[9] R.-H. Chen, L. C. Chow, and J. E. Navedo, "Optimal spray characteristics in water spray cooling," International Journal of Heat and Mass Transfer, vol. 47, 2004, pp. 5095-5099.
[10] L. Lin and R. Ponnappan, "Heat Transfer Characteristics Of Spray Cooling In A Closed Loop," International Journal of Heat and Mass Transfer, vol. 46, 2003, pp. 3737-3746.
[11] W. Jia and H. H. Qiu, "Experimental Investigation Of Droplet Dynamics And Heat Transfer In Spray Cooling," Experimental Thermal and Fluid Science, vol. 27, 2003, pp. 829-838.
[12] S.-S. Hsieh, T.-C. Fan, and H.-H. Tsai, "Spray cooling characteristics of water and R-134a. Part I: nucleate boiling," International Journal of Heat and Mass Transfer, vol. 47, 2004, pp. 5703-5712.
[13] S. S. Hsieh, T. C. Fan, and H. H. Tsai, "Spray cooling characteristics of water and R-134a. Part II: transient cooling," International Journal of Heat and Mass Transfer, vol. 47, 2004, pp. 5713-5724.
[14] A. G. Pautsch and T. A. Shedd, "Spray Impingement Cooling With Single- And Multiple-Nozzle Arrays. Part I: Heat Transfer Data Using FC-72," International Journal of Heat and Mass Transfer, vol. 48, 2005, pp. 3167-3175.
[15] T. A. Shedd and A. G. Pautsch, "Spray Impingement Cooling With Single- And Multiple-Nozzle Arrays. Part Ii: Visualization And Empirical Models," International Journal of Heat and Mass Transfer, vol. 48, 2005, pp. 3176-3184.
[16] S. S. Hsieh and C. H. Tien, "R-134a Spray Dynamics and Impingement Cooling in the Non-Boiling Regime," International Journal of Heat and Mass Transfer, vol. 50, 2007, pp. 502-512.
[17] S.-S. Hsieh and H.-H. Tsai, "Thermal and Flow Measurements of Continuous Cryogenic Spray Cooling," Archives of dermatological Research, vol. 298, 2006, pp. 82-95.
[18] N. Karwa, S. R. Kale, and P. M. V. Subbarao, "Experimental study of non-boiling heat transfer from a horizontal surface by water sprays," Experimental Thermal and Fluid Science, vol. 32, 2007, pp. 571-579.
[19] M. Visaria and I. Mudawar, "Theoretical and experimental study of the effects of spray inclination on two-phase spray cooling and critical heat flux," International Journal of Heat and Mass Transfer, vol. 51, 2008, pp. 2398-2410.
[20] M. Visaria and I. Mudawar, "Effects of High Subcooling on Two-Phase Spray Cooling and Critical Heat Flux," International Journal of Heat and Mass Transfer, vol. 51, 2008, pp. 5269-5278.
[21] Y. Wang, M. Liu, D. Liu, K. Xu, and Y. Chen, "Experimental Study on the Effects of Spray Inclination on Water Spray Cooling Performance in Non-boiling Regime," Experimental Thermal and Fluid Science, vol. 34, 2010, pp. 933-942.
[22] Y. Wang, M. Liu, D. Liu, and K. Xu, "Heat Flux Correlation for Spray Cooling in the Nonboiling Regime," Heat Transfer Engineering, vol. 32, 2011, pp. 1075-1081.
[23] Y. Tao, X. Huai, L. Wang, and Z. Guo, "Experimental characterization of heat transfer in non-boiling spray cooling with two nozzles," Applied Thermal Engineering, vol. 31, 2011, pp. 1790-1797.
[24] W. L. Cheng, F. Y. Han, Q. N. Liu, and H. L. Fan, "Spray characteristics and spray cooling heat transfer in the non-boiling regime," Energy, vol. 36, 2011, pp. 3399-3405.
[25] Y. Hou, X. Liu, J. Liu, M. Li, and L. Pu, "Experimental Study on Phase Change Spray Cooling," Experimental Thermal and Fluid Science, vol. 46, 2013, pp. 84-88.
[26] Z. Zhang, J. Li, and P.-X. Jiang, "Experimental Investigation of Spray Cooling on Flat and Enhanced Surfaces," Applied Thermal Engineering, vol. 51, 2013, pp. 102-111.
[27] T. Orzechowski and S. Wciślik, "Instantaneous Heat Transfer for Large Drops Levitating Over a Hot Surface," International Journal of Heat and Mass Transfer, vol. 73, 2014, pp. 110-117.
[28] R. Guo, J. Wu, H. Fan, and X. Zhan, "The Effects of Spray Characteristic on Heat Transfer During Spray Quenching of Aluminum Alloy 2024," Experimental Thermal and Fluid Science, vol. 76, 2016, pp. 211-220.
[29] N. Zhou, F. Chen, Y. Cao, M. Chen, and Y. Wang, "Experimental investigation on the performance of a water spray cooling system," Applied Thermal Engineering, vol. 112, 2017, pp. 1117-1128.
[30] G. E. Lorenzetto and A. H. Lefebvre, "Measurements of Drop Size on a Plain-Jet Airblast Atomizer," AIAA Journal, vol. 15, 1977, pp. 1006-1010.
[31] A. H. Lefebvre, X. F. Wang, and C. A. Martin, "Spray characteristics of aerated-liquid pressure atomizers," Journal of Propulsion and Power, vol. 4, 1988, pp. 293-298.
[32] Byung-Joon Rho, S.-J. Kang, J.-H. Oh, and S.-G. Lee, "Swirl effect on the spray characteristics of a twin-fluid jet," KSME International Journal,, vol. 12, 1998, pp. 899-906.
[33] A. Kuerath, B. Wende, and W. Leuckel, "Influence Of Liquid Flow Conditions On Spray Characteristics Of Internal-Mixing Twin-Fluid Atomizers," International Journal of Heat and Fluid Flow, vol. 20, 1999, pp. 513-519.
[34] N.P.Yadav and A. Kushari, "Behavior of Spray in a Twin- Fluid Atomizer," vol. 2011,
[35] P. Watanawanyoo, H. Hirahara, H. Mochida, T. Furukawa, M. Nakamura, and S. Chaitep, "Experimental Investigations on Spray Characteristics in Twin-Fluid Atomizer," Procedia Engineering, vol. 24, 2011, pp. 816-822.
[36] Z. Li, Y. Wu, C. Cai, H. Zhang, Y. Gong, K. Takeno, K. Hashiguchi, and J. Lu, "Mixing and Atomization Characteristics in an Internal-Mixing Twin-Fluid Atomizer," Fuel, vol. 97, 2012, pp. 306-314.
[37] P. Krawczyk, K. Badyda, and S. Młynarz, "Effect of The Air to Water Ratio on The Performance of Internal Mixing Two-Fluid Atomizer," Chemical and Process Engineering, vol. 37, 2016,
[38] Y. Xia, L. Khezzar, M. Alshehhi, and Y. Hardalupas, "Droplet Size and Velocity Characteristics of Water-Air Impinging Jet Atomizer," International Journal of Multiphase Flow, vol. 94, 2017, pp. 31-43.
[39] M. Zaremba, L. Weiß, M. Malý, M. Wensing, J. Jedelský, and M. Jícha, "Low-Pressure Twin-Fluid Atomization: Effect of Mixing Process on Spray Formation," International Journal of Multiphase Flow, vol. 89, 2017, pp. 277-289.
[40] Tilton, Donald E ; Pais, Martin R ; Chow, Louis C, " High Power Density Spray Cooling," 1988.
[41] J. H. Kim, S. M. You, and S. U. S. Choi, "Evaporative Spray Cooling Of Plain And Microporous Coated Surfaces," International Journal of Heat and Mass Transfer, vol. 47, 2004, pp. 3307-3315.
[42] J. Shen, J. A. Liburdy, D. V. Pence, and V. Narayanan, "Droplet Impingement Dynamics: Effect of Surface Temperature during Boiling and Non-boiling Conditions," J Phys Condens Matter, vol. 21, 2009, pp. 464133.
[43] R. Srikar, T. Gambaryan-Roisman, C. Steffes, P. Stephan, C. Tropea, and A. L. Yarin, "Nanofiber Coating of Surfaces for Intensification of Drop or Spray Impact Cooling," International Journal of Heat and Mass Transfer, vol. 52, 2009, pp. 5814-5826.
[44] D. S. Zhu, J. Y. Sun, S. D. Tu, Z. D. Wang, L. Guo, D. D. Joseph, Y. Matsumoto, Y. Sommerfeld, and Y. Wang, "Experimental Study of Non-boiling Heat Transfer by High Flow Rate Nanofluids Spray," vol. 2010, pp. 476-482.
[45] H. Bellerová and M. Pohanka, "Spray Cooling by Multi-walled Carbon Nanotubes and Fe Nanoparticles," vol. 1, 2011, pp. 293-304.
[46] T.-B. Chang, S.-C. Syu, and Y.-K. Yang, "Effects of Particle Volume Fraction on Spray Heat Transfer Performance of Al2O3-Water Nanofluid," International Journal of Heat and Mass Transfer, vol. 55, 2012, pp. 1014-1021.
[47] H. Bostanci, D. P. Rini, J. P. Kizito, V. Singh, S. Seal, and L. C. Chow, "High Heat Flux Spray Cooling With Ammonia Investigation of Enhanced Surfaces for HTC," International Journal of Heat and Mass Transfer, vol. 75, 2014, pp. 718-725.
[48] Z. Zhang, P.-X. Jiang, X.-L. Ouyang, J.-N. Chen, and D. M. Christopher, "Experimental Investigation of Spray Cooling on Smooth and Micro-Structured Surfaces," International Journal of Heat and Mass Transfer, vol. 76, 2014, pp. 366-375.


[49] Z. Zhang, P.-X. Jiang, D. M. Christopher, and X.-G. Liang, "Experimental Investigation of Spray Cooling on Micro-,Nano-,and Hybrid-Structured Surfaces," International Journal of Heat and Mass Transfer, vol. 80, 2015, pp. 26-37.
[50] S. Sarangi, J. A. Weibel, and S. V. Garimella, "Effect of Particle Size on Surface-Coating Enhancement of Pool Boiling Heat Transfer," International Journal of Heat and Mass Transfer, vol. 81, 2015, pp. 103-113.
[51] R. J. Moffat, "Describing the uncertainties in experimental results," Experimental Thermal and Fluid Science, vol. 1, 1988, pp. 3-17.
[52] J. R. Taylor, "An Introduction to Error Analysis: The Study of Uncertainties in Physical Measurements" University Science Books, 1997.