• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>International Journal of Heat and Mass Transfer >Experimental study of buoyancy effect and its criteria for heat transfer of supercritical R134a in horizontal tubes
【24h】

Experimental study of buoyancy effect and its criteria for heat transfer of supercritical R134a in horizontal tubes

机译：超临界R134a在水平管中的浮力效应及其传热准则的实验研究

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Supercritical organic Rankine cycles (ORCs) are a promising waste heat recovery technology because of their high thermal efficiency and lower exergy loss. Heat transfer characteristics must be considered for vapor generator design in ORCs. This paper focuses on the buoyancy effect on heat transfer characteristics in horizontal tubes of supercritical R134a, a widely used ORC working fluid, whose supercritical heat transfer characteristics have been less widely studied. Experiments of supercritical R134a flowing in horizontal tubes with different inner diameters of 10.3 mm and 16 mm were conducted to obtain basic experimental data. The influences of heat flux, mass flux, and tube diameter on heat transfer were investigated with an emphasis on the buoyancy effect. This study attempts to extend the applicability of existing buoyancy criteria to organic fluids in horizontal tubes to quantitatively analyze the buoyancy effect. Existing buoyancy criteria, which were developed for water, were evaluated and the threshold values determining the onset of the buoyancy effect in heated horizontal tubes were determined for the present data. A simple parameter of qd (0.7)/G(12) not based on wall temperature was developed to be correlated with the maximum temperature difference between the top and bottom surfaces for convenience in engineering use. This parameter was validated with both the present data and supercritical water data from the literature. (C) 2018 Elsevier Ltd. All rights reserved.
机译：超临界有机朗肯循环（ORC）是一种很有前途的废热回收技术，因为它们具有较高的热效率和较低的火用损失。对于ORC中的蒸汽发生器设计，必须考虑传热特性。本文着重研究浮力对超临界R134a水平管传热特性的影响，超临界R134a是一种广泛使用的ORC工作流体，其对超临界传热特性的研究较少。进行了超临界R134a在不同内径为10.3 mm和16 mm的水平管中流动的实验，以获得基本的实验数据。研究了热通量，质量通量和管径对传热的影响，重点是浮力效应。这项研究试图将现有浮力标准的适用性扩展到水平管中的有机流体，以定量分析浮力效果。评估了针对水制定的现有浮力标准，并针对当前数据确定了确定加热水平管中浮力作用开始的阈值。为了方便工程使用，开发了一个不基于壁温的简单参数qd（0.7）/ G（12）与顶部和底部表面之间的最大温差相关。现有数据和文献中的超临界水数据均验证了该参数。 （C）2018 Elsevier Ltd.保留所有权利。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号