含离散颗粒热喷流颗粒分布特征数值研究及验证
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摘要
气溶胶红外隐身技术是针对飞机发动机喷口的热部件及发动机排出的高温燃气在3~5μm及8~14μm波段的红外辐射而研究的一种有效的隐身方法,在相同的材料特性条件下,气溶胶粒子的分布特征成为影响气溶胶红外辐射抑制效果的主要因素。
本文基于气固两相流理论,借助商业CFD计算软件FLUENT,对含离散颗粒的热喷流进行数值计算。首先对含离散颗粒热喷流计算模型进行研究,分析不同计算模型对计算结果的影响,其中,湍流模型对气相的速度场的计算结果影响较大,而对温度场和组分浓度场的计算结果影响不大。经比较发现Realizable k-ε湍流模型更适合于本文的研究对象。在计算中,计算域长度需要取到L/D≈26。然后运用实验的方法对所选计算模型的合理性进行验证。设计了一套含离散颗粒喷流试验系统,包括供气系统、下粉装置、喷嘴及PIV测量系统。实验中采用PIV测量技术对含离散颗粒喷流的速度场和颗粒浓度场进行测量,结果与数值模拟结果基本一致。在实验验证了计算模型的合理性的基础上,着重分析了不同离散颗粒喷射量、喷射角度、喷射速度及外围气流速度对离散颗粒在流场中的分布特征的影响规律:当外界气流M =0时,增加颗粒喷射量能有效提高气溶胶颗粒在空间各点的浓度,但对颗粒在空间的分布影响较小;增加颗粒喷射速度对离散颗粒浓度分布影响较小;喷射角度为0度时空间各点浓度分布比较均匀;随外界气流速度提高,颗粒与气流开始发生掺混的位置逐渐后移,外界气流速度越大,颗粒浓度场的扩散角越小,且空间各点颗粒浓度越小。
Aerosol obscure is an effectual technique of I.R. suppression, which is applied to decrease the I.R. radiation of heat exhaust and hot nozzle in the bands from 3μm to 5μm and 8μm to14μm. In the same material condition, the distribution characteristics of discrete should be the main factor that affects the suppression effect.
Based on the gas-solid two-phase flow theory, numerical simulation of heat exhaust with particles is done by using the commercial CFD software FLUENT. First of all, we do research on the calculation model of heat exhaust with particulates, try to find the influence of different models on the calculation results. It is Realized that the turbulence models have great influence on the velocity field and little influence on the temperature field and concentration field. By comparison, Realizable k-εmodel is the best suitable one for this calculation model. The calculation domain needs to be L / D≈26 in length. And then an experiment is done to verify the reasonableness of our calculation model. This experimental system mainly includes gas supply system, particle dropping system, aerosol injection system and PIV measurement system. We get the velocity field and the concentration field in the experiment. Within limits, the numerical calculation results closely fit the experimental results. After the reasonableness of the calculation model is proved, the analysis focuses on the influence law of injection amount, velocity, angle and the velocity of external stream on the distribution of discrete particles. When the velocity of external stream is 0, to increase the particle injection amount can effectively increase the particle concentration in space, but the distribution of particles in space is less influenced and so do the increase of injection velocity. When the injection angle is 0 degree, the concentration of the particles is evenly distributed. With increase of the external stream velocity, the position that the particles and hot exhaust begin to mix together is getting further. The higher the velocity of the external stream is, the smaller the diffusion angle of the particle concentration field and the particle concentration value is.
本文基于气固两相流理论,借助商业CFD计算软件FLUENT,对含离散颗粒的热喷流进行数值计算。首先对含离散颗粒热喷流计算模型进行研究,分析不同计算模型对计算结果的影响,其中,湍流模型对气相的速度场的计算结果影响较大,而对温度场和组分浓度场的计算结果影响不大。经比较发现Realizable k-ε湍流模型更适合于本文的研究对象。在计算中,计算域长度需要取到L/D≈26。然后运用实验的方法对所选计算模型的合理性进行验证。设计了一套含离散颗粒喷流试验系统,包括供气系统、下粉装置、喷嘴及PIV测量系统。实验中采用PIV测量技术对含离散颗粒喷流的速度场和颗粒浓度场进行测量,结果与数值模拟结果基本一致。在实验验证了计算模型的合理性的基础上,着重分析了不同离散颗粒喷射量、喷射角度、喷射速度及外围气流速度对离散颗粒在流场中的分布特征的影响规律:当外界气流M =0时,增加颗粒喷射量能有效提高气溶胶颗粒在空间各点的浓度,但对颗粒在空间的分布影响较小;增加颗粒喷射速度对离散颗粒浓度分布影响较小;喷射角度为0度时空间各点浓度分布比较均匀;随外界气流速度提高,颗粒与气流开始发生掺混的位置逐渐后移,外界气流速度越大,颗粒浓度场的扩散角越小,且空间各点颗粒浓度越小。
Aerosol obscure is an effectual technique of I.R. suppression, which is applied to decrease the I.R. radiation of heat exhaust and hot nozzle in the bands from 3μm to 5μm and 8μm to14μm. In the same material condition, the distribution characteristics of discrete should be the main factor that affects the suppression effect.
Based on the gas-solid two-phase flow theory, numerical simulation of heat exhaust with particles is done by using the commercial CFD software FLUENT. First of all, we do research on the calculation model of heat exhaust with particulates, try to find the influence of different models on the calculation results. It is Realized that the turbulence models have great influence on the velocity field and little influence on the temperature field and concentration field. By comparison, Realizable k-εmodel is the best suitable one for this calculation model. The calculation domain needs to be L / D≈26 in length. And then an experiment is done to verify the reasonableness of our calculation model. This experimental system mainly includes gas supply system, particle dropping system, aerosol injection system and PIV measurement system. We get the velocity field and the concentration field in the experiment. Within limits, the numerical calculation results closely fit the experimental results. After the reasonableness of the calculation model is proved, the analysis focuses on the influence law of injection amount, velocity, angle and the velocity of external stream on the distribution of discrete particles. When the velocity of external stream is 0, to increase the particle injection amount can effectively increase the particle concentration in space, but the distribution of particles in space is less influenced and so do the increase of injection velocity. When the injection angle is 0 degree, the concentration of the particles is evenly distributed. With increase of the external stream velocity, the position that the particles and hot exhaust begin to mix together is getting further. The higher the velocity of the external stream is, the smaller the diffusion angle of the particle concentration field and the particle concentration value is.
引文
[1]刘世良.红外隐身技术与热隐身材料的研究进展.飞航导弹,4:55～59.
[2]蔡毅.浅谈现代战斗机的红外隐身技术.红外技术,1994,6(6):6～10.
[3]康青.红外隐身机理与应用.红外技术,1996,18(1):25～27.
[4]钟华,李自力.隐身技术,北京:国防工业出版社,1999.
[5]吴凤明.导弹:战争的革命,北京:海潮出版社,2001.
[6] [美]理查特,丹尼斯.气溶胶手册,北京:原子能出版社,1987.
[7]崔杰.红外隐身技术在动力系统中的应用.推进技术,1995,3:81～83.
[8]吴明忠,刘怀忠.红外隐身技术在飞行器中的应用.红外技术,1998,20(2):9～12.
[9]谈浩元,吴林山,吴文龙.颗粒气溶胶抑制红外辐射的影响因素.隐身技术,1993,(4):6～13.
[10]刘世良.红外隐身技术的研究及发展.湖北航天科技,1993,(4):7～12.
[11]李毅.非球形微粒及其形成烟幕的消光机理研究.南京:南京理工大学,2001.
[12]张净玉,常海萍.球形离散颗粒抑制热喷流红外辐射规律研究.博士学位论文,南京:南京航空航天大学,2008.
[13]聂传虹,韩无杰.粉末气溶胶红外消光作用的试验与理论分折.桂林电子工业学院学报,2002,2(2):50～55.
[14]韩启祥,谈浩元.气溶胶抑制尾喷口红外辐射的试验研究.南京航空航天大学学报,1995,27(3):341～345.
[15]段瑞伟,常海萍.气溶胶红外隐身材料的选择研究.硕士学位论文,南京:南京航空航天大学,2003.
[16]么东升,常海萍.气溶胶红外消光特性机理研究.硕士学位论文,南京:南京航空航天大学,2005.
[17]陈雄斌,常海萍.气溶胶喷射系统的设计及其性能研究.硕士学位论文,南京:南京航空航天大学,2005.
[18]周昊,孙国俊,郑立刚等.带有侧边风的气固两相射流混合特性的试验研究.中国电机工程学报,2003,23(8):187～190.
[19]张东东,许宏庆,何枫.气固两相射流瞬时速度场和浓度场的PIV研究.清华大学学报(自然科学版),2003,43(11):1491～1494.
[20]许宏庆,何文奇,李良杰等.应用PIV技术对气固两相射流场进行瞬时测量.第五届全国流动显示学术会议,239～246.
[21]余常昭.紊动射流.北京:高教出版社,1993.4.
[22] Shaughnessy, E. J. and Morton, J. B. Laser light-scattering measurements of particle concentration in a turbulent jet. J. Fluid. Mech.
[23] Becker,H. A. Hottel,H. C. and Willian,G. C. The nozzle-fluid concentration filed of the round turbulent free jet. J. Fluid Mech, 1967, Vol. 30:285~303.
[24] Chevary, R. and Tutu, H. K. Intermitterly and preferential transport of heat in a round jet, J. Fluid Mech, 1978, Vol. 88(1): 133~160.
[25] Birch, A. D. Brown, D. R, Dodson, M. G, and Thoma, J. R. The Turbulent concentration field of a me thane jet. J. Fluid Mech, 1978, Vol. 88(3): 431~449.
[26] Cruyningen I venetal. Quantiative imaging of concentration by planar laser-induced fluorescene. Experiments in Fluids, 1990, 10.
[27] Yoda, M. and Fieldler, E. H. The round jet in a uniform counterflow visualization and mean con centration measurements. Experiments in Fluids. 1996, Vol. 21: 427~436.
[28] Nickels, T. B. and Perry,A. E. An experiments in Fluids. 1996,Vol. 21: 427~436.
[29] Weisgraber, T. H. and Liepman, D. Turbulent structure during transition to self-similarity in a round jet. Exp. Fluid. 1998. Vol. 24: 210~224.
[30] Davidson, M. J. and Pun, K. L. Weakly adwected jets in crossflow J. Hydr. Engrg. ASCE,1999, Vol. 123(1): 47~58.
[31] Adrian, W. K. L. and Hongwei Wang. Simultaneous velocity and concentration measurements of buoyant jet discharges with conbined DPIV and DLIF. In: proceeding of Enviromental Hydraulics, eds. , Lee, Jayawardena and Wang, 1999 Balkema, and Rotterdam. 129~134.
[32]吴飞雪,董守平,时铭显.激光粒子成像技术测定旋风分离器内颗粒浓度场的实验研究.石油大学学报,2000(6):72~76.
[33]马银亮.高浓度气固两相流的数值模拟研究.博士学位论文,浙江:浙江大学,2001.
[34]周力行.多相湍流反应流体力学.北京:国防工业出版社,2002.
[35] Yuu-S, Umekage-T, Tabuchi-M, Direct numerical simulation for three-dimensional gas-solid two-phase jet. using two-way method and experimental verification. JSME International Journal, 1996, B39(2): 230～238.
[36] Yuu-S, Ikeda-K, Umekage-T, Flow-field prediction and experimental-verification oflow-Reynolds-number gas-particle turbulent jets, Collids and Surfaces, 1996, A109: 13～27.
[37] Uthuppan J,Aggarwal S K,Grinstein F Fetal,Particle dispersion in a transitional axisym metric jet numerical simulation,A/AA Journal,1994,32(10):2004～2014.
[38]范全林,张会强,郭印诚等.气粒两相平面湍射流拟序结构的大涡模拟.燃烧科学与技术,2001,7(1):21～26.
[39]范全林,张会强,郭印诚等.入流滑移条件对两相射流特性影响的大涡模拟研究. 2001年,7(1):99～103.
[40] FLUENT User Guide,FLUENT Incorporated,1998.
[41] FLUENT Help 6.1.
[42] A. Coppalle and P. Vervisch. The Total Emissivities of High-Temperature Flames: Combust. Flame. 1983.49:101-108.
[43] T. F. Smith, Z. F. Shen, and J. N. Friedman. Evaluation of Coefficients for the Weighted Su m of Gray Gases Model. Heat Transfer, 1982. 104: 602-608.
[2]蔡毅.浅谈现代战斗机的红外隐身技术.红外技术,1994,6(6):6～10.
[3]康青.红外隐身机理与应用.红外技术,1996,18(1):25～27.
[4]钟华,李自力.隐身技术,北京:国防工业出版社,1999.
[5]吴凤明.导弹:战争的革命,北京:海潮出版社,2001.
[6] [美]理查特,丹尼斯.气溶胶手册,北京:原子能出版社,1987.
[7]崔杰.红外隐身技术在动力系统中的应用.推进技术,1995,3:81～83.
[8]吴明忠,刘怀忠.红外隐身技术在飞行器中的应用.红外技术,1998,20(2):9～12.
[9]谈浩元,吴林山,吴文龙.颗粒气溶胶抑制红外辐射的影响因素.隐身技术,1993,(4):6～13.
[10]刘世良.红外隐身技术的研究及发展.湖北航天科技,1993,(4):7～12.
[11]李毅.非球形微粒及其形成烟幕的消光机理研究.南京:南京理工大学,2001.
[12]张净玉,常海萍.球形离散颗粒抑制热喷流红外辐射规律研究.博士学位论文,南京:南京航空航天大学,2008.
[13]聂传虹,韩无杰.粉末气溶胶红外消光作用的试验与理论分折.桂林电子工业学院学报,2002,2(2):50～55.
[14]韩启祥,谈浩元.气溶胶抑制尾喷口红外辐射的试验研究.南京航空航天大学学报,1995,27(3):341～345.
[15]段瑞伟,常海萍.气溶胶红外隐身材料的选择研究.硕士学位论文,南京:南京航空航天大学,2003.
[16]么东升,常海萍.气溶胶红外消光特性机理研究.硕士学位论文,南京:南京航空航天大学,2005.
[17]陈雄斌,常海萍.气溶胶喷射系统的设计及其性能研究.硕士学位论文,南京:南京航空航天大学,2005.
[18]周昊,孙国俊,郑立刚等.带有侧边风的气固两相射流混合特性的试验研究.中国电机工程学报,2003,23(8):187～190.
[19]张东东,许宏庆,何枫.气固两相射流瞬时速度场和浓度场的PIV研究.清华大学学报(自然科学版),2003,43(11):1491～1494.
[20]许宏庆,何文奇,李良杰等.应用PIV技术对气固两相射流场进行瞬时测量.第五届全国流动显示学术会议,239～246.
[21]余常昭.紊动射流.北京:高教出版社,1993.4.
[22] Shaughnessy, E. J. and Morton, J. B. Laser light-scattering measurements of particle concentration in a turbulent jet. J. Fluid. Mech.
[23] Becker,H. A. Hottel,H. C. and Willian,G. C. The nozzle-fluid concentration filed of the round turbulent free jet. J. Fluid Mech, 1967, Vol. 30:285~303.
[24] Chevary, R. and Tutu, H. K. Intermitterly and preferential transport of heat in a round jet, J. Fluid Mech, 1978, Vol. 88(1): 133~160.
[25] Birch, A. D. Brown, D. R, Dodson, M. G, and Thoma, J. R. The Turbulent concentration field of a me thane jet. J. Fluid Mech, 1978, Vol. 88(3): 431~449.
[26] Cruyningen I venetal. Quantiative imaging of concentration by planar laser-induced fluorescene. Experiments in Fluids, 1990, 10.
[27] Yoda, M. and Fieldler, E. H. The round jet in a uniform counterflow visualization and mean con centration measurements. Experiments in Fluids. 1996, Vol. 21: 427~436.
[28] Nickels, T. B. and Perry,A. E. An experiments in Fluids. 1996,Vol. 21: 427~436.
[29] Weisgraber, T. H. and Liepman, D. Turbulent structure during transition to self-similarity in a round jet. Exp. Fluid. 1998. Vol. 24: 210~224.
[30] Davidson, M. J. and Pun, K. L. Weakly adwected jets in crossflow J. Hydr. Engrg. ASCE,1999, Vol. 123(1): 47~58.
[31] Adrian, W. K. L. and Hongwei Wang. Simultaneous velocity and concentration measurements of buoyant jet discharges with conbined DPIV and DLIF. In: proceeding of Enviromental Hydraulics, eds. , Lee, Jayawardena and Wang, 1999 Balkema, and Rotterdam. 129~134.
[32]吴飞雪,董守平,时铭显.激光粒子成像技术测定旋风分离器内颗粒浓度场的实验研究.石油大学学报,2000(6):72~76.
[33]马银亮.高浓度气固两相流的数值模拟研究.博士学位论文,浙江:浙江大学,2001.
[34]周力行.多相湍流反应流体力学.北京:国防工业出版社,2002.
[35] Yuu-S, Umekage-T, Tabuchi-M, Direct numerical simulation for three-dimensional gas-solid two-phase jet. using two-way method and experimental verification. JSME International Journal, 1996, B39(2): 230～238.
[36] Yuu-S, Ikeda-K, Umekage-T, Flow-field prediction and experimental-verification oflow-Reynolds-number gas-particle turbulent jets, Collids and Surfaces, 1996, A109: 13～27.
[37] Uthuppan J,Aggarwal S K,Grinstein F Fetal,Particle dispersion in a transitional axisym metric jet numerical simulation,A/AA Journal,1994,32(10):2004～2014.
[38]范全林,张会强,郭印诚等.气粒两相平面湍射流拟序结构的大涡模拟.燃烧科学与技术,2001,7(1):21～26.
[39]范全林,张会强,郭印诚等.入流滑移条件对两相射流特性影响的大涡模拟研究. 2001年,7(1):99～103.
[40] FLUENT User Guide,FLUENT Incorporated,1998.
[41] FLUENT Help 6.1.
[42] A. Coppalle and P. Vervisch. The Total Emissivities of High-Temperature Flames: Combust. Flame. 1983.49:101-108.
[43] T. F. Smith, Z. F. Shen, and J. N. Friedman. Evaluation of Coefficients for the Weighted Su m of Gray Gases Model. Heat Transfer, 1982. 104: 602-608.