針對一往後傾斜10o的橫風噴流火焰，利用聲波激擾燃料噴流，在一開放式的風洞中以實驗方法研究噴流的擾動強度對燃燒火焰的行為及熱化學特性的影響。橫風雷諾數與噴流雷諾數分別固定為1527與2165，噴流對應橫風之動量通量比為0.1，激擾史卓數為0.73，噴流的擾動強度變化為0至1.26。使用高速攝影機記錄燃燒火焰的演化過程;藉由R-type的熱電偶線量測燃燒火焰的溫度場;利用氣體分析儀偵測燃燒火焰的燃燒生成器組成。隨著噴流擾動強度的改變，噴流燃燒火焰形成三種主要的火焰特徵模態，分別為下洗火焰模態、過渡火焰模態及發展火焰模態。下洗火焰模態形成在擾動強度低於0.163時，火焰行為與未受激擾的燃燒火焰相似，只是火焰迴流泡、下洗火焰及火焰長度隨著擾動強度的增強而減小。過渡火焰模態形成在擾動強度界於0.163與0.66之間，火焰行為是雙火焰，雙火焰的長度隨著擾動強度的不同而有所差異。發展火焰模態形成在擾動強度界於0.66與0.987之間。當擾動強度大於1.26時，燃燒火焰熄滅。針對不同的燃燒火焰特徵模態，量測燃燒生成物與溫度分佈。燃燒火焰生成物中的未燃燒燃料C3H8、NO及CO的濃度結果顯示，在靠近噴流管口下游處，下洗火焰模態及過渡火焰模態中低擾動強度時具有較高的濃度分佈。溫度量測的結果顯示，過渡火焰模態的溫度分佈較廣，並且峰值溫度較高。

The aim of the present study is to experimentally investigate the effect of pulsation intensity on the behavior and thermal chemistry of the transverse reacting jet inclined at a small backward angle of 10ᵒ in an open-loop wind tunnel when the fuel supply is acoustically excited. The jet-to-crossflow momentum flux ratio was 0.1 and excitation Strouhal number was 0.73. The jet pulsation intensity was varied from 0 to 1.26. Flame-evolution processes were studied using streak images of flame obtained by high speed camera. The temperature field was measured by using a fine-wire R-type thermal couple. The concentration measurement of the combustion products (O2, CO, CO2, UHC and NO) was carried out using NOVA gas analyzer. Three characteristic flame modes are observed when the pulsation intensity increases from 0 to 1.26. Downwash dominated flame mode occurs at Ipul < 0.163 and the lengths of recirculation bubble, downwash flame, and total flame reduces with increasing pulsation intensity. Transition flame mode formed at 0.163 < Ipul < 0.66 with the appearance of dual flame. The flame length of the dual flame changes at various pulsation intensities. Developed flame mode appears at 0.66 < Ipul < 0.987, in which the downwash flame disappears and the dual flame merges together. The flame blows off at Ipul > 1.26. The concentration of combustion induced pollutants such as unburned hydrocarbons (UHC), NO and CO near the burner tube field is higher for downwash dominated flame mode and low range pulsation intensities within the transition mode as compared to the high range pulsation intensities of transition and developed flame mode. The temperature measurement in median (y = 0) and transverse plane for transition mode records higher temperature peaks as compared to downwash dominated and developed flame mode.

[1] Brzustowski, T. A. (1976). Prog. Energy Combust. Sci.2 , 129-141.
[2] El Behery, R. E., Mohamad, A., & Kamal, M. (2005). Combustion enhancement of a gas flare using acoustical excitation. Combustion science anf technology, Vol. 177, No. 9, 1627-1659.
[3] Ginevsky, A., Vlasov, Y. V., & Karavosov, R. (2004). Acoustic control of turbulent jets. Springer-Verlag, Berlin, .
[4] Gollahalli, S. R., & Nanjudappa, B. (2007). Burner wake stabilized gas jet flames in cross-flow. combustion science and technology, 109, 327-346.
[5] Han, D., Orozco, V., & M.G. Mungal. (2000). Simultaneous measurements of velocity and CH. AIAA J. 38 (2000), 1643-1649.
[6] Hsu, C. M., & F., H. R. (2011). Effects of acoustic excitation at resonance strouhal numbers on characteristics of elevated transverse jet. experimental thermal and fluid science vol. 35, 1370-1382.
[7] Huang, R. F., & Chang, J. M. (1994). The stability and visualized flame structures of acombusting jet in cross flow. combustion and flame vol. 98 No.3 , 267-278.
[8] Huang, R. F., & Wang, S. M. (1999). Charateristic flow modes of wake-stabilized jet flames in a transverse air stream. combustion and flame, Vol. 117, No.- 1-2, 59-77.
[9] Huang, R. F., & Yang, M. (1996). Thermal and concentration fields of burner attached jet flames in crossflow. combustion and flame 105, 211-224.
[10] Huang, R. F., & Hsu, C. M. (2012). Turbulent Flows of an acoustically excited elevated transverse jet. AIAA journal 50 , 1964-1978.
[11] Ishizawa, M., Shinoda, M., Yamishita, H., Katagiri, H., Kitagawa, K., & A.K., G. (2004). Effect of oscillating excitation on a methane-air diffusion flame. 42nd AIAA aerospace sciences meeting and exhibit,.
[12] Jessen, W., WSchroder, W., & Klass, M. ( 2007,). Evolution of jets effusing from inclined holes into crossflow. International Journal of heat and fluid flow, 1312–1326.
[13] Kalghatgi, G. T. (1981). Blow-out stability of gaseous jet diffusion flames part-iii: effect of burner orientation to wind direction. Combustion science and technology, vol 28, 241-245.
[14] Khan, Z. U., & Johnson, J. (2000). On vortex generating jets. International Journal of Heat and Fluid Flow, 506-511.
[15] Kostiuk, L., Majeski, A., Poudenx, P., Johnson, M., & Wilson, D. (2000). Scaling of wake-stabilized jet diffusion flames in a transverse air stream. Proceedings of the combustion institute, Vol. 28, 553-559.
[16] M’Closkey, R. T., King, J. M., Cortelezzi, L., & Karagozian, A. R. (2002). The actively controlled jet in crossflow. journal of fluid mechanics Vol. 452, 325-335.
[17] Marr, K. C., Clemens, N. T., & Ezekoye, O. (2012). Mixing Characteristics and emissions of strongly forced non-premixed and partially premixed jet flames in cross flow. Combustion and flame, vol. 159, 707-721.
[18] Mohammad Goudarzi Khouygani a, R. F. Huang (2015). Flow characteristics in median plane of a backward-inclined elevated. Experimental Thermal and Fluid Science, 164-174.
[19] Savas, O., Huang, R. F., & Gollahalli, S. (1997). Structure of the flow field of a nonpremixed gas jet flame in cross-flow. Journal of energy resources technology, vol.119, 119-137.
[20] Wang, R. F. Huang (1999). Characteristics flow modes of wake stabilized jet flames in a transverse air stream. combustion and flame 117, 59-77.
[21] Yaras, M. I. (2004). Measurements of Surface-Roughness Effects on the Development of a Vortex Produced by an Inclined Jet in Cross-Flow. J. Fluids Eng 126, 346-354.
[22] Eroglu, A. and Breidenthal R. E., “Structure, Penetration, and Mixing of Pulsed Jet in Crossflow,” AIAA Journal, Vol. 39, No. 3, 2001, pp. 417-423.
[23] Johari, H., “Scaling of Fully Pulsed Jets in Crossflow,” AIAA Journal, Vol. 44, No. 11, 2006, pp. 2719-2725.
[24] Megerian, S., Davitian, J., Alves, L. S. de B., and Karagozian, A. R., “Transverse-Jet Shear-Layer Instabilities. Part 1. Experimental Studies,” Journal of Fluid Mechanics, Vol. 593, 2007, pp. 93-129.
[25] Davitian, J., Hendrickson, C., Getsinger, D., M’Closkey, R. T., and Karagozian, A. R., “Strategic Control of Transverse Jet Shear Layer Instabilities,” AIAA Journal, Vol. 48, No. 9, 2010, pp. 2145-2156.
[26] Ginversky, A. S., Valsov, Y. V., and Karavosov, R. K., Acoustic Control of Turbulent Jet, Springer-Verlag, Berlin, 2004.
[27] Kinsler, L. E. and Frey A. R., Fundamentals of Acoustics, Second ed., Wiley, New York, 1982.
[28] Tennekes, H. and Lumley, J. L., A First Course in Turbulence, MIT Press, Cambridge, 1972, pp. 248-261.
[29] Tritton, D. J., Physical Fluid Dynamics, Oxford University Press, Oxford, 1988, pp. 123-151.
[30] Pope, S. B., Turbulent Flows, Cambridge University Press, Cambridge, 2000.
[31] Y. Minamoto, H. Kolla, R.W. Grout, A. Gruber, J.H. Chen, Effect of fuel
composition and differential diffusion on flame stabilization in reacting
syngas jets in turbulent cross-flow, Combust. Flame 162 (2015) 3569–3579.
[32] R.V. Bandaru, S.R. Turns, Turbulent jet flames in a crossflow: effects of some
jet, crossflow, and pitot-flame parameters on emissions, Combust. Flame 121
(2000) 137–151.
[33] A.M. Steinberg, R. Sadanandan, C. Dem, P. Kutne, W. Meier, Structure and
stabilization of hydrogen jet flames in cross-flow, Proc. Combust. Inst. 34
(2013) 1499–1507.
[34] V.R. Katta, D.L. Blunck, N. Jiang, A. Lynch, J.R. Gord, S. Roy, On flames
established with air jet in cross flow of fuel-rich combustion products, Fuel 150
(2015) 360–369.
[35] J.L. Ellzey, J.G. Berbe, E.Z.F. Tay, D.E. Foster, Total soot yield from a propane
diffusion flame in cross-flow, Combust. Sci. Technol. 71 (1990) 41–52.
[36] J.A. Wagner, S.W. Grib, M.W. Renfro, B.M. Cetegen, Flowfield measurements
and flame stabilization of a premixed reacting jet in vitiated crossflow,
Combust. Flame 162 (2015) 3711–3727
[37] G.T. Kalghatgi, The visible shape and size of a turbulent hydrocarbon jet
diffusion flame in a cross-wind, Combust. Flame 52 (1983) 91–106
[38] A. Askari, S.J. Bullman, M. Fairweather, F. Swaffield, The concentration field of a turbulent jet in a cross-wind, Combust. Sci. Technol. 73 (1990) 463–478
[39] E. Bourguignon, M.R. Johnson, L.W. Kostiuk, The use of a closed-loop wind
tunnel for measuring the combustion efficiency of flames in a cross flow,
Combust. Flame 119 (1999) 319–334.