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首页> 外文期刊>International Journal of Heat and Mass Transfer >Measured and predicted heat transfer coefficients for boiling zeotropic mixed refrigerants in horizontal tubes
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Measured and predicted heat transfer coefficients for boiling zeotropic mixed refrigerants in horizontal tubes

机译：测量和预测水平管中沸腾共沸混合制冷剂的传热系数

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摘要

The use of mixed gas working fluids has become common in Joule-Thomson type cryocoolers for a variety of applications. However, there is a scarcity of data currently available with supporting theory capable of predicting the heat transfer coefficients associated with two-phase, multi-component mixtures at cryogenic temperatures. This paper aims to fill this void by providing experimental data for the heat transfer coefficient associated with of multicomponent zeotropic mixtures boiling in small channels over temperatures ranging from 100 K to room temperature. The sensitivity of the measured heat transfer coefficient to parameters such as heat flux, mass flux, pressure, tube diameter, and mixture composition is also presented. The results indicate that the heat transfer process is driven, principally, by convective boiling; however, composition, diameter, and surface roughness affect the measured heat transfer coefficient. Evaporating pressure has less relevance compared to the other parameters. The actual experimental data collected as part of this effort and additional data from Nellis et al. (2005) are used to evaluate models to characterize the heat transfer process for boiling zeotropic mixtures in horizontal tubes. The heat transfer coefficient data is predicted well using correlations described by Granryd (1991) and Little (2008). The Granryd correlation is the recommended correlation to predict heat transfer coefficient of zeotropic mixtures because it shows the best accuracy with an Absolute Average Deviation (AAD) of 16% and predicts 83% of the data with a relative error lower than 25%. The Little correlation exhibits greater accuracy at high Reynolds number, high thermodynamic quality, or both; however, its accuracy is substantially reduced for low qualities and low Reynolds number.
机译：在焦耳-汤姆森（Joule-Thomson）型低温冷却器中，混合气体工作流体的使用已变得很普遍，可用于多种应用。但是，目前缺乏支持理论能够预测与低温下的两相，多组分混合物相关的传热系数的支持理论的数据。本文旨在通过提供与在100 K至室温范围内在小通道中沸腾的多组分共沸混合物相关的传热系数的实验数据来填补这一空白。还介绍了测得的传热系数对诸如热通量，质量通量，压力，管径和混合物组成等参数的敏感性。结果表明，传热过程主要是由对流沸腾驱动的。但是，成分，直径和表面粗糙度会影响测得的传热系数。与其他参数相比，蒸发压力的相关性较小。作为这项工作的一部分，收集了实际的实验数据以及Nellis等人的其他数据。 （2005年）用于评估模型，以表征水平管中沸腾的共沸混合物的传热过程。使用Granryd（1991）和Little（2008）描述的相关性可以很好地预测传热系数数据。建议使用Granryd相关性来预测共沸混合物的传热系数，因为它具有16％的绝对平均偏差（AAD）并能预测83％的数据，且相对误差低于25％，显示了最佳的准确性。较小的相关性在高雷诺数，高热力学质量或同时在这两者下表现出更高的准确性；但是，对于低质量和低雷诺数，其精度会大大降低。

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  • 作者

    Rodrigo Barraza; Gregory Nellis; Sanford Klein; Douglas Reindl;

  • 作者单位

    Department of Mechanical Engineering, University of Wisconsin, 1500 Engineering Drive, Madison, WI 53706, USA,Department of Mechanical Engineering, Universidad Tecnica Federico Santa Maria, Av. Espana 1680, Valparaiso, Chile,Vicuna Mackenna 3939, Santiago, Chile;

    Department of Mechanical Engineering, University of Wisconsin, 1500 Engineering Drive, Madison, WI 53706, USA;

    Department of Mechanical Engineering, University of Wisconsin, 1500 Engineering Drive, Madison, WI 53706, USA;

    Department of Mechanical Engineering, University of Wisconsin, 1500 Engineering Drive, Madison, WI 53706, USA;

  • 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 coefficient; Joule-Thomson; Zeotropic; Mixed gas; Mixture; Non-azeotropic;

    机译：传热系数;焦耳-汤姆森共沸混合气体混合物;非共沸的;

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