Distributed steady and dynamic modelling of dry-expansion evaporators

被引:58
作者
Jia, X
Tso, CP [1 ]
Jolly, P
Wong, YW
机构
[1] Nanyang Technol Univ, Sch Mech & Prod Engn, Singapore 2263, Singapore
[2] Carrier Transicold S Pte Ltd, Singapore, Singapore
来源
INTERNATIONAL JOURNAL OF REFRIGERATION-REVUE INTERNATIONALE DU FROID | 1999年 / 22卷 / 02期
关键词
dry-expansion evaporator; steady state; transient state;
D O I
10.1016/S0140-7007(98)00043-7
中图分类号
O414.1 [热力学];
学科分类号
摘要
A general distributed parameter model is presented to describe both steady and dynamic behaviors of dry-expansion evaporators. The homogeneous and three different non-homogeneous two-phase flow models are used to evaluate the impact of different how models on the accuracy of the simulation. The experimental work was carried out on a full-scale refrigeration system with R-134a as the working fluid and without frost formation at the evaporator. Comparison between the modelling and experimental measurements shows that the drift flux flow models give satisfactory predictions. The simulation results indicate that an even air temperature distribution off the evaporator may be obtained by controlling liquid dry-out point at the two ends of the coil. The study also indicates that the counterflow configuration provides a higher heat exchange efficiency with a slower transient response compared with the cocurrent-flow configuration. A general distributed parameter model is presented to describe both steady and dynamic behaviors of dry-expansion evaporators. The homogeneous and three different non-homogeneous two-phase flow models are used to evaluate the impact of different flow models on the accuracy of the simulation. The experimental work was carried out on a full-scale refrigeration system with R-134a as the working fluid and without frost formation at the evaporator. Comparison between the modelling and experimental measurements shows that the drift Bur flow models give satisfactory predictions. The simulation results indicate that an even air temperature distribution off the evaporator may be obtained by controlling liquid dry-out point at the two ends of the coil. The study also indicates that the counterflow configuration provides a higher heat exchange efficiency with a slower transient response compared with the cocurrent-flow configuration. (C) 1999 Elsevier Science Ltd and IIR. All rights reserved.
引用
收藏
页码:126 / 136
页数:11
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