稳态与瞬态冲击射流换热性能实验对比
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摘要
为了对比研究稳态与瞬态单孔冲击射流的传热性能,采用热色液晶测温技术获取实验件被冲击表面的传热系数分布。实验中改变了冲击雷诺数Re和冲击孔直径比L/d,利用工业相机拍摄实验件凹表面颜色变化过程,计算并对比两种射流条件下局部努塞尔数Nu_D的分布,并与文献值进行比较。研究表明相对于稳态冲击射流,瞬态冲击射流的传热性能更佳。通过记录整个冲击射流过程,得到Nu_D随时间t变化关系。驻点附近NuD随冲击的进行逐渐减小并趋于稳定。随冲击雷诺数Re增大或冲击孔直径比L/d接近6,瞬态冲击射流的强化传热效果逐渐明显,强化效果可达15%以上。
In order to compare the heat transfer performance of the steady and transient single hole impingement jets, the heat transfer coefficient distribution of the impact surface was obtained by thermochromic liquid crystal. In the study, the impact Reynolds number Re and the impact distance to diameter ratio L/d were changed.The color change process of the concave surface of the experimental part was photographed by the industrial camera. The local Nusselt number Nu_D distribution of two kinds of jet conditions was calculated and compared. In addition, the results were compared with the literature value. The research shows that the heat transfer performance is better than that of steady jet under transient jet impingement. By recording the whole impinging jet process, the relationship was obtained between Nu_D and impact time t. The Nu_D around stagnation point gradually decreases with the impact going and tends to be stable. With the increase of the Re or L/d close to 6, the heat transfer enhancement effect of transient impinging jet is obvious, and the enhancement result is more than 15%.
In order to compare the heat transfer performance of the steady and transient single hole impingement jets, the heat transfer coefficient distribution of the impact surface was obtained by thermochromic liquid crystal. In the study, the impact Reynolds number Re and the impact distance to diameter ratio L/d were changed.The color change process of the concave surface of the experimental part was photographed by the industrial camera. The local Nusselt number Nu_D distribution of two kinds of jet conditions was calculated and compared. In addition, the results were compared with the literature value. The research shows that the heat transfer performance is better than that of steady jet under transient jet impingement. By recording the whole impinging jet process, the relationship was obtained between Nu_D and impact time t. The Nu_D around stagnation point gradually decreases with the impact going and tends to be stable. With the increase of the Re or L/d close to 6, the heat transfer enhancement effect of transient impinging jet is obvious, and the enhancement result is more than 15%.
引文
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[11]Eibeck P A,Keller J O,Bramlette T T,et al.Pulse Combustion:Impinging Jet Heat Transfer Enhancement[J].Combustion Science and Technology,1993,94:147-165.
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[13]周静伟,杨兴贤,耿丽萍,等.非稳态冲击射流强化传热试验研究[J].机械工程学报,2010,46(6):144-148.
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[15]Yan X.A Preheated-Wall Transient Method Using Liquid Crystals for the Measurement of Heat Transfer on External Surfaces and in Ducts[D].Davis:Dissertation University of California,1993.
[16]Baughn J W,Yan X.An Insertion Technique Using the Transient Method with Liquid Crystals for Heat Transfer Measurements in Ducts[J].ASME Fouling and Enhancement Interactions,1991,164:77-83.
[17]Oriana C,Gabriel G,Gweneal H,et al.Experimental and Numerical Investigation of a Fully Confined Impingement Round Jet[J].International Journal of Heat and Mass Transfer,2013,65:873-882.
[18]Kline S J,Mcklintock F A.Describing Uncertainties in Single Sample Experiments[J].Mechanical Engineering,1953,75(1):3-8.
[19]Baughn J W,Shimizu S.Heat Transfer Measurements from a Surface with Uniform Heat Flux and an Impinging Jet[J].Journal of Heat Transfer,1989,111(4):1096-1098.
[20]Lytle D,Webb B W.Air Jet Impingement Heat Transfer at Low Nozzle-Plate Spacings[J].International Journal of Heat&Mass Transfer,1994,37(12):1687-1697.
[21]Kim K,Wiedner B,Camci C.Fluid Dynamics and Convective Heat Transfer in Impinging Jets through Implementation of a High Resolution Liquid Crystal Technique,Part II:Navier-Stokes Computation of Impulsively Starting Heat Transfer Experiments[C].Tokyo:International Symposium on Air-Breathing Engines,1993.
[22]Lee C H,Lim K B,Lee S H,et al.A Study of the Heat Transfer Characteristics of Turbulent Round Jet Impinging on an Inclined Concave Surface Using Liquid Crystal Transient Method[J].Experimental Thermal and Fluid Science,2007,(31):559-565.
[2]耿铁,李德群,周华民,等.冲击射流及其强化换热的研究进展[J].机械设计与制造,2006,14(6):154-156.
[3]王超,常士楠,吴孟龙,等.过冷大水滴飞溅特性数值分析[J].航空动力学报,2014,29(4):1004-1011.
[4]Cao Y H,Wu Z L,Su Y.Aircraft Flight Characteristics in Icing Conditions[J].Progress in Aerospace Sciences,2015,74(5):62-80.
[5]周莉,徐浩军,龚胜科,等.飞机结冰特性及防除冰技术研究[J].航空动力学报,2010,25(6):105-110.
[6]李军,曹从咏,徐强.固体火箭燃气射流近场形成与发展的数值模拟[J].推进技术,2003,24(5):410-413.(LI Jun,CAO Cong-yong,XU Qiang.Numerical Simulation of the Form and Development of Rocket Gas Near Flow Field[J].Journal of Propulsion Technology,2003,24(5):410-413.)
[7]王克菲,朱惠人,李中洲,等.出流方式对阵列冲击换热的影响[J].航空动力学报,2010,25(10):2273-2278.
[8]王克菲,朱惠人,张斌,等.带气膜孔出流和侧向出流的冲击换热实验[J].航空动力学报,2010,25(5):1011-1017.
[9]王磊,张靖周,杨卫华.密集型阵列冲击射流换热特性实验[J].航空动力学报,2009,24(6):1264-1269.
[10]周静伟,王玉刚,耿丽萍.粗糙表面对非定常冲击射流传热的影响[J].工程热物理学报,2009,30(4):687-690.
[11]Eibeck P A,Keller J O,Bramlette T T,et al.Pulse Combustion:Impinging Jet Heat Transfer Enhancement[J].Combustion Science and Technology,1993,94:147-165.
[12]Zumbrunnen D A,Aziz M.Convective Heat Transfer Enhancement Due to Intermittency in an Impinging Jet[J].ASME Journal of Heat Transfer,1993,115:91-98.
[13]周静伟,杨兴贤,耿丽萍,等.非稳态冲击射流强化传热试验研究[J].机械工程学报,2010,46(6):144-148.
[14]Kim K,Camci C.Fluid Dynamics and Convective Heat Transfer in Impinging Jets Through Implementation of a High Resolution Liquid Crystal Technique,Part I:Flow and Heat Transfer Experiments[J].International Journal of Turbo and Jet Engines,1995,12(1):1-12.
[15]Yan X.A Preheated-Wall Transient Method Using Liquid Crystals for the Measurement of Heat Transfer on External Surfaces and in Ducts[D].Davis:Dissertation University of California,1993.
[16]Baughn J W,Yan X.An Insertion Technique Using the Transient Method with Liquid Crystals for Heat Transfer Measurements in Ducts[J].ASME Fouling and Enhancement Interactions,1991,164:77-83.
[17]Oriana C,Gabriel G,Gweneal H,et al.Experimental and Numerical Investigation of a Fully Confined Impingement Round Jet[J].International Journal of Heat and Mass Transfer,2013,65:873-882.
[18]Kline S J,Mcklintock F A.Describing Uncertainties in Single Sample Experiments[J].Mechanical Engineering,1953,75(1):3-8.
[19]Baughn J W,Shimizu S.Heat Transfer Measurements from a Surface with Uniform Heat Flux and an Impinging Jet[J].Journal of Heat Transfer,1989,111(4):1096-1098.
[20]Lytle D,Webb B W.Air Jet Impingement Heat Transfer at Low Nozzle-Plate Spacings[J].International Journal of Heat&Mass Transfer,1994,37(12):1687-1697.
[21]Kim K,Wiedner B,Camci C.Fluid Dynamics and Convective Heat Transfer in Impinging Jets through Implementation of a High Resolution Liquid Crystal Technique,Part II:Navier-Stokes Computation of Impulsively Starting Heat Transfer Experiments[C].Tokyo:International Symposium on Air-Breathing Engines,1993.
[22]Lee C H,Lim K B,Lee S H,et al.A Study of the Heat Transfer Characteristics of Turbulent Round Jet Impinging on an Inclined Concave Surface Using Liquid Crystal Transient Method[J].Experimental Thermal and Fluid Science,2007,(31):559-565.