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首页> 外文期刊>Journal of Heat Transfer >Heat Transfer Enhancement Due to Frequency Doubling and Ruelle-Takens-Newhouse Transition Scenarios in Symmetric Wavy Channels
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Heat Transfer Enhancement Due to Frequency Doubling and Ruelle-Takens-Newhouse Transition Scenarios in Symmetric Wavy Channels

机译：对称波浪通道中由于倍频和Ruelle-Takens-Newhouse过渡方案而导致的传热增强

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摘要

Heat transfer enhancement characteristics, through a transition scenario of flow bifurcations in symmetric wavy wall channels, are investigated by direct numerical simulations of the mass, momentum, and energy equations using spectral element methods. Flow bifurcations, transition scenarios, and heat transfer characteristics are determined by increasing the Reynolds numbers from a laminar to a transitional flow for the geometrical aspect ratios r =0.125 and r =0.375. The numerical results demonstrate that the transition scenario to transitional flow regimes depends on the aspect ratio. For r = 0.375, the transition scenario is characterized by one Hopf flow bifurcation in a frequency-doubling transition scenario, where further increases in the Reynolds number always lead to periodic flows; whereas, for r =0.125, the transition scenario is characterized by a first Hopf flow bifurcation from a laminar to a time-dependent periodic flow and a second Hopf flow bifurcation from a periodic to a quasiperiodic flow. For r = 0.125, the flow bifurcation scenario is similar to the Ruelle-Takens-Newhouse (RTN) transition scenario to Eulerian chaos observed in asymmetric wavy and grooved channels. The periodic and quasiperiodic flows are characterized by fundamental frequencies ω_1, and ω_1 and ω_2, respectively. For the aspect ratio r= 0.375, the Nusselt number increases slightly as the Reynolds number increases in the laminar regime until it reaches a critical Reynolds number of Re_c≈126. As the flow becomes periodic, and then quasi-periodic, the Nusselt number continuously increases with respect to the laminar regime, up to a factor of 4, which represents a significant heat transfer enhancement due to a better flow mixing.
机译：通过使用对称谱波方法对质量，动量和能量方程进行直接数值模拟，研究了对称波浪壁通道中分流过渡情况下的传热增强特性。对于几何长宽比r = 0.125和r = 0.375，通过增加层流到过渡流的雷诺数，可以确定分流，过渡情况和传热特性。数值结果表明，向过渡流态的过渡情况取决于长宽比。当r = 0.375时，过渡方案的特征是在倍频过渡方案中出现一个霍夫夫分流，雷诺数的进一步增加总是导致周期性的流动。反之，对于r = 0.125，过渡场景的特征是从层流到与时间有关的周期性流的第一霍普夫流分叉，从周期性到准周期的第二霍普夫流分叉。当r = 0.125时，分流情况类似于在不对称波浪和沟槽通道中观察到的Ruelle-Takens-Newhouse（RTN）向欧拉混沌过渡的情况。周期性和准周期性的流动分别由基本频率ω_1，ω_1和ω_2表征。对于纵横比r = 0.375，在层流状态中，随着雷诺数的增加，努塞尔特数会略有增加，直到达到Re_c≈126的临界雷诺数。随着流量变为周期性，然后变为准周期性，相对于层流状态，Nusselt数不断增加，直到因子4，由于更好的流量混合，代表了显着的传热增强。

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  • 来源
    《Journal of Heat Transfer》 |2009年第9期|76-83|共8页
  • 作者

    Amador M. Guzman; Raul A. Hormazabal; Tania A. Aracena;

  • 作者单位

    Departamento de Ingenieria Mecanica,Universidad de Santiago de Chile,Casilla 10233 Alameda 3363,Estacian Central,Santiago, Chile;

    Departamento de Ingenieria Mecanica,Universidad de Santiago de Chile,Casilla 10233 Alameda 3363,Estacian Central,Santiago, Chile;

    Departamento de Ingenieria Mecanica,Universidad de Santiago de Chile,Casilla 10233 Alameda 3363,Estacian Central,Santiago, Chile;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    heat transfer enhancement; flow transition scenarios; symmetric wavy channels;

    机译：传热增强;流过渡方案;对称波浪通道;

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