背向階梯結構簡單但現象多變，應用十分廣泛，而當加入壁面噴流後流場機制與混合行為更加複雜。本文藉由實驗方法，探討在背向階梯之分離流場中，壁面蒸散之流體對於流場行為以及冷卻機制之影響，透過定性之流場觀測以及定量之量測，進一步釐清了文獻中對於噴流所造成之流場模態結構與流場特性未解之處。另一方面，再透過蒸散壁面之噴流區域的控制，藉由薄膜模態之噴流質量流率比在不同噴流區域的選定下，研究整體流場之溫度表現與冷卻行為，並探討低溫噴流與高溫進口流之間的混合現象，進一步深入瞭解蒸散冷卻之機制與效應。
實驗中透過流場觀測，細察各流場模態間不同區域之流場特徵，再藉由速度場之量測瞭解流場速度分佈及紊流特性，並針對流場之壓力及擾動進行量測分析。在控制噴流範圍之條件中，進一步透過流場溫度以及壁面溫度之穩態及暫態量測，探討溫度分佈以及降溫程度，並進行熱傳係數之估算，以便瞭解流場及壁面之冷卻行為。

在四種流場模態之結構歸納中，透過局部之觀測歸納出四種流場模態更為完整之流場型態，可確實區分各流場模態之結構，並以速度量測結果作一對照與印證，發現四種模態之階梯角落、主迴流區、再接觸區、以及下游渦漩逸散之結構皆有其不同之表現。在局部噴流的條件中，分別針對0-7H、3.5-10.5H、7-14H之噴流位置的選定來進行分析，其中局部噴流0-7H所得之流場冷卻區域較為廣闊，然而下游區域之流場受到高溫主進口流之強烈混合與衝擊效果，因而表現出較高之紊流動能以及較差之低溫冷卻表現，而噴流區域之壁面由於擁有內機制之冷卻，因此擁有較佳之冷卻趨勢，顯示出蒸散冷卻對壁面之良好保護冷卻效果；另一方面，降溫係數之結果顯示，低溫區域與最大降溫幅度非重疊之區域，可做為不同應用之參考。在熱傳係數方面，透過壁面史丹頓數之計算，可判斷各條件下壁面熱傳分佈趨勢。除此之外，在局部噴流0-7H之條件下，於流場下游約27H位置加上一結構後，對於14H前方之流場整體的降溫效果與冷卻趨勢造成巨大之改善與突破，整體低溫區域大幅增加，特別值得重視。

Abbott, D. E., and Kline, S. J., 1962, "Experimental Investigation of Subsonic Turbulent Flow Over Single and Double Backward-facing Steps," ASME Journal of Basic Engineering, Vol. 84D, pp. 317-325.
Abu-Hijleh, B. A/K, 2000, "Heat Transfer from a 2D Backward Facing Step with Isotropic Porous Floor Segments," International Journal of Heat and Mass Transfer, Vol. 43, pp. 2727-2737.
Adams, E. W., and Eaton, J. K., 1988, "An LDA Study of the Backward-Facing Step Flow, Including the Effects of Velocity Bias," Journal of Fluids Engineering, Vol. 110, pp. 275-282.
Adams, E. W., and Johnston, J. P., 1988, "Flow Structure in the Near-Wall Zone of a Turbulent Separated Flow," AIAA Journal, Vol. 26, pp. 932-939.
Armaly, B. F., Durst, F., Pereira, J. C. F., and Schonung, B., 1983, "Experimental and Theoretical Investigation of Backward-facing Step, " Journal of Fluid Mechanic, Vol. 127, pp. 473-496.
Aung, W., 1983, "An Experimental Study of Laminar Heat Transfer Downstream of Backsteps," Journal of Heat and Mass Transfer, Vol. 105, pp. 823-829.
Boizumault, F., Harmand, S., and Desmet, B., 2000, "Influence of the Characteristics of a Aerodynamically Perturbated Flow on the Local Heat Transfer by Convection from a Wall," International Journal of Heat and Mass Transfer, Vol. 43, pp. 791-806.
Bradshaw, P., and Wong, F. Y. F., 1972, "The Reattachment and Relaxation of Turbulent Shear Layer," Journal of Fluid Mechanics, Vol. 52, pp. 113-135.
Brown, G. L., and Roshko, A., 1974, "On Density Effects and Large Structure in Turbulent Mixing Layers, " Journal of fluid Mechanics, Vol. 64, Part 4, pp. 775-816.
Cheng, Y. C., Hwang, G. J., and Ng, M. L., 1994, "Developing Laminar Flow and Heat Transfer in a Rectangular Duct with One-Walled Injection and Suction," International Journal of Heat and Mass Transfer, Vol. 37, pp. 2601-2613.
Chiang, T. P., Sheu, Tony W. H., and Fang, C. C., 1999, "Nimerical Investigation of Vortical Evolution ib a Backward-facing Step Expansion Flow, " Applied Mathematical Modeling, Vol. 23, pp. 915-932.
Collier, Jr. F. S., and Schetz, J. A., 1984, "Injection into a Turbulent Boundary Layer through Different Porous Surfaces," AIAA Journal, Vol. 22, No. 6, pp. 839-841.
Eaton, J. K., and Johnston, J. P., 1981, "A Review of Research on Subsonic Turbulent Flow Reattachment," AIAA Journal, Vol. 19, pp. 1093-1100.
Eckert, E. R. G., and Cho, H. H., 1994, "Transition from Transpiration to Film Cooling," International Journal of Heat and Mass Transfer, Vol. 37, Suppl. 1, pp. 3-8.
Ganji, A. R., and Sawyer, R. F., 1980, "Experimental Study of the Flowfield of a Two-Dimensional Premixed Turbulent Flame," AIAA Journal, Vol. 18, No. 7, pp. 817-824.
Giovannini, A., and Bortolus, N. V., 1997, "Heat Transfer in the Reattachment Zone downstream of a Backward-facing Step," Revue Generale de Thermique, Vol. 37, pp. 89-102.
Hsu, C. H., Chang, Y. P., and Chen, B. C., 1999, "Transient Mixed Convection of a Second-grade Fluid past a Backward-facing Step," International Journal of Non-Linear Mechanics, Vol. 34, pp. 881-893.
Isomoto, K., and Honami, S., 1989, "The Effect of Inlet Turbulence Intensity on the Reattachment Process Over a Backward-Facing Step," Journal of Fluids Engineering, Vol. 111, pp. 87-92.
Kim, J., Kline, S. J., and Jonston, J. P., 1980, "Investigation of a Reattaching Turbulent Shear Layer: Flow Over a Backward-Facing Step," Journal of Fluids Engineering, Vol. 102, pp. 302-308.
Kondoh, T., Nagano, Y., and Tsuji, T., 1993, "Computational Study of Laminar Heat Transfer Downstream of a Backward-Facing Step," International Journal of Heat and Mass Transfer, Vol. 36, pp. 577-591.
Lee, S. C., Yang, J. T., and Chao, Y. C., 2001, "Large Eddy Simulation of Transition from Transpiration to Film Cooling over the Backstep Flow," Book of Abstracts PSFVIP-3, March 18-21, Maui, Hawaii, U.S.A., pp.149-150.
Robet, J. C., Campolina-Franca, G. A., Robert, P. Pagnier, and Lallemand, A., 1997, "Experimental Study of Transpiration Gas Cooling through a Porous Wall," Revue Generale de Thermique, Vol. 37, pp. 89-102.
Soong, C. Y., and Hsueh, W. C., 1993, "Mixed Convection in a Suddenly-Expanded Channel with Effects of Cold Fluid Injection," International of Journal Heat and Mass Transfer, Vol. 36, pp. 1477-1484.
Tihon, J., Legrand, J., and Lgentilhomme, P., 2001, "Near-wall Investigation of Backward-facing Step Flows," Experiments in Fluids, Vol. 31, pp. 484-493.
Tsai, C. H., Yang, J. T., and Yang, H. T., 1993, "Experimental Investigation of Heat Transfer and Fluid Dynamics of a Hot Flow in a Combustor," Proceeding of the Third World Conference on Experimental Heat Transfer, Fluid Mechanics and Thermodynamics, Hawaii, October 31-November 5, pp. 1130-1140.
Tsou, F. K., Chen, S. J., and Aung, W., 1991, "Starting Flow and Heat Transfer Downstream of a Backward-Facing Step," Journal of Heat Transfer, Vol. 113, pp. 583-589.
Yang, J. T., Gu J. D., and Ma W. J., 2001, "Transient Cooling Effect by Wall Mass Injection After Backstep in High Temperature Flow Field," International Journal of Heat and Mass Transfer, Vol. 44, pp. 843-855.
Yang, J. T., and Tsai, C. H., 1996, "High Temperature Heat Transfer of Separated Flow over A Sudden-Expansion with Base Mass Injection," International Journal of Heat and Mass Transfer, Vol. 39, pp. 2293-2301.
Yang, J. T., and Ma, W. J., 2001, "Flow Patterns after a Backstep with Wall Mass Injection," Journal of Fluid Mechanics (submitted).
Yang, J. T., Ma, W. J., and Tsai, C. H., 1998, "Transient Effect of Micro-Jet Cooling on a Flat Plate in Separated Flow Field," Proceedings of the Eleventh International Symposium on Transport Phenomena, Hsinchu, Taiwan, R. O. C., November 29- December 3, pp. 278- 282.
Yogesh, G. P., and Raghunandan, B. N., 1989, "Flow Structure and Heat Transfer Characteristics Behind a Diaphragm in the Presence of a Diffusion Flame," International Journal of Heat and Mass Transfer, Vol. 32, No. 1, pp. 19-28.
馬萬鈞，2000，分離流場之蒸散冷卻現象研究，國立清華大學動力機械工程學系博士論文。
陳躍仁，2000，高溫紊流之壁面蒸散冷卻模態研究，國立清華大學動力機械工程學系碩士論文。
蘇裕傑，2001，高溫分離流場之壁面蒸散冷卻暫態研究，國立清華大學動力機械工程學系碩士論文。
顧景德，1996，高溫紊態分流場中壁面噴流冷卻效應之暫態研究，國立清華大學動力機械工程學系碩士論文。