共查询到20条相似文献,搜索用时 484 毫秒
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为了获得开缝布置方式对开缝翅片管换热器传热与阻力特性的影响规律,对5种不同翅片管换热器进行了数值模拟研究,并进行了模化试验验证。结果表明:增加开缝会提高翅片管换热器的传热性能,但阻力也随之增加;与开缝位置相比,开缝数量对开缝翅片管换热器传热与阻力特性的影响更大;在Re=4800~7500日时,开缝翅片管换热器综合流动传热性能 随着Re数的增大而增大;在5种翅片中,开缝翅片的综合流动传热性能高于普通平直翅片;数值模拟与试验结果偏差较小,采用数值模拟方法能够比较准确地分析开缝翅片管换热器的传热与阻力特性。 相似文献
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根据大型电站锅炉省煤器的运行工况,对单H形和双H形翅片管束气侧的传热与阻力特性进行了模化试验研究,并利用Fluent软件对H形翅片管束的流场和温度场进行了数值模拟,得到单H形和双H形翅片管束的传热与阻力特性变化规律.结果表明:H形翅片管束的传热和阻力特性与气体的Re有关,随着气体Re的增大,气侧Nu不断增大,传热性能提高,而Eu则逐渐减小,并趋于定值;在相同Re下,单H形翅片管束气侧Nu大于双H形翅片管束气侧Nu,而气侧Eu则小于双H形翅片管束气侧Eu;数值计算结果与试验结果误差较小,采用数值计算方法能比较准确地分析H形翅片管束的流动与传热特性. 相似文献
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为了增强螺旋盘管的传热性能,对现有的普通螺旋盘管进行优化设计,提出一种管壁向内凸起形成环肋的异型管,称为横纹螺旋盘管。通过数值模拟方法对横纹螺旋盘管和普通盘管内部流动和传热过程进行模拟。应用场协同原理对其速度场和温度场的协同作用进行分析。实验数据与仿真结果的误差在5%以内,验证了数值模拟方法的正确性。在不同Re(雷诺数)条件下,计算两种盘管的Nu(努塞尔数),进而与Gnielinski(格尼林斯基)修正公式计算结果进行比较,误差在10%以内。结果表明:环肋结构通过工质旋转流动破坏边界层厚度,改善了管内速度场与温度场的协同程度,从而实现了强化传热。在较高的Re范围内,横纹螺旋盘管的Nu为普通盘管的1.29~1.43倍。因此,横纹螺旋盘管具有更好的传热性能,为异型螺旋盘管的研究及工程应用提供一定的理论依据。 相似文献
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建立微型燃气轮机CW(交叉波浪型,Cross Wavy)原表面回热器三维周期性充分发展数值计算模型,对芯体内传热和阻力特性进行了分析,确定了质量流量和温度水平对换热量及压降的影响,给出了CW原表面芯体板内阻力、传热因子以及努塞尔数与雷诺数之间的经验关联式。传热及阻力性能分析结果表明:随着雷诺数的增大,回热器芯体单元传热系数增大,传热量逐渐增加,并且随着低压高温烟气侧的进口温度升高,传热量增加幅度增大;回热器芯体单元回热度随雷诺数的增大而减小,随燃气进口温度升高而减小。 相似文献
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This paper presents the study of the flow structure and heat transfer, and also their correlations on the four walls of a radial cooling passage model of a gas turbine blade. The investigations focus on heat transfer and aerodynamic measurements in the channel, which is an accurate representation of the configuration used in aeroengines. Correlations for the heat transfer coefficient and the pressure drop used in the design of radial cooling passages are often developed from simplified models. It is important to note that real engine passages do not have perfect rectangular cross sections, but include corner fillet, ribs with fillet radii and special orientation. Therefore, this work provides detailed fluid flow and heat transfer data for a model of radial cooling geometry which possesses very realistic features. 相似文献
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This paper presents exergetic and engineering analyses as well as a simulation of gas turbine-based cogeneration plants consisting of a gas turbine, heat recovery steam generator and steam turbine. The exergy analysis is based on the first and second laws of thermodynamics. The engineering analysis is based on both the methodology of levelized cost and the pay back period. To simulate these systems, an algorithm has been developed. Two cogeneration cycles, one consisting of a gas turbine and the other of a gas turbine and steam turbine and process to produce electricity and process heat have been analyzed. The results showed good agreement with the reported data. 相似文献
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This paper presents the study of the influence of channel geometry on the flow structure and heat transfer,and also their correlations on all the walls of a radial cooling passage model of a gas turbine blade.The investigations focus on the heat transfer and aerodynamic measurements in the channel,which is an accurate representation of the configuration used in aeroengines.Correlations for the heat transfer coefficient and the pressure drop used in the design of internal cooling passages are often developed from simplified models.It is important to note that real engine passages do not have perfect rectangular cross sections,but include a comer fillets,ribs with fillet radii and a special orientation.Therefore,this work provides detailed fluid flow and heat transfer data for a model of radial cooling geometry which has very realistic features. 相似文献
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板翅式换热器是舰载燃气轮机首选换热器形式。针对平直型翅片的矩形通道的结构特点,建立了流动换热分析的耦合计算模型,采用计算流体动力学(CFD)方法对间冷器的通道流场进行了数值模拟。给出并分析了计算区域内多个截面的温度、压力、速度、局部传热系数等参数的分布图形和变化趋势,并考察了不同工况下间冷器的工作能力。 相似文献