Abstract

New empirical models for evaluating heat-transfer coefficients for condensation on banks of tubes were developed using an experimental database of over 4000 individual data points for 7 different condensing fluids and 13 different tube bank configurations. New empirical models within each of the free and forced convection flow regimes for both of the steam and non-steam fluids separately were obtained, including the relevant dimensionless groups that may affect the heat transfer during the condensation. Two models within the free-convection flow regime for the non-steam were proposed due to large volume and variation of data in this regime. While comparing the results of the new empirical models with the recent database; it was proposed that the overestimation for some of the non-steam data of Shah (1978 and 1981) was due to the presence of the non-condensable gas (air) within the flowing fluid. In terms of predicting the tube bank thermal performance and condensation of flowing fluid, the results of the newly developed models were seen to be the most reliable and accurate when compared with the existing models mentioned in this paper. An overall agreement was seen with the existing experimental database within an average absolute of the errors of about 15%. For steam data, the present models were seen to yield the most accurate results for the inline and staggered tube banks when compare with other empirical and analytical models. However, for non-steam fluids (R-12, R-21 and R-113 only) flowing through staggered tube bank, Honda et al. (1989) model is recommended.

中文翻译：

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普通管束冷凝的新经验模型

摘要

使用7个不同冷凝液和13种不同管束配置的4000多个单独数据点的实验数据库，开发了用于评估管束上冷凝水的传热系数的新经验模型。获得了分别针对蒸汽和非蒸汽流体的自由对流流动模式和强制对流流动模式内的新经验模型，包括可能影响冷凝过程中传热的相关无量纲组。由于这种情况下的大量数据和变化，提出了非蒸汽自由对流流动模式内的两个模型。在将新的经验模型的结果与最新的数据库进行比较时；有人提出，对Shah（1978和1981）的一些非蒸汽数据的高估是由于流动的流体中存在不可凝气体（空气）。在预测管束的热性能和流动流体的冷凝方面，与本文中提到的现有模型相比，新开发的模型的结果被认为是最可靠，最准确的。在现有的实验数据库中，总体平均误差在15％左右。对于蒸汽数据，与其他经验模型和分析模型相比，当前模型对于直列和交错管束产生了最准确的结果。但是，对于流经交错管束的非蒸汽流体（仅R-12，R-21和R-113），Honda等人。