摘要
本文对余热利用中常用安装有H型翅片的管翅式换热器在波动流动条件下的换热性能和流阻特性进行了数值模拟研究。揭示了非稳态波动流动的不同波动时均速度、波动幅度和波动周期对流动和换热的影响机理。结果表明,在不同时均速度下,Nu数随Re数的变化趋势基本一致,而Eu数具有明显的迟滞现象;在不同波动幅度下,Nu数和Eu数的变化都很大,在Re数的极小值附近尤为明显;在不同波动周期下,Nu数和Eu数在所有Re数范围内均基本相同,影响可以忽略。最终获得了波动流动下换热和阻力计算的关联式。
In this paper,a comprehensive transient three-dimensional model for heat transfer performance and flow resistance is applied to investigate the characteristics of fm-and-tube heat exchanger with H-typed fin.The overall and local dynamic response performance of Nu number and Eu number under volatile flow conditions are analyzed in details.The results indicate that under different time-averaged velocity,the tendency of the Nu number is basically the same within the same cycle time.For the Eu number,both the value and change tendency are very different from each other.Under different volatile amplitude,the tendency of Nu number shows obvious distortion near the minimum of Re number.Meanwhile,the Eu number also has been distinctly influenced by the volatile amplitude,especially at smaller Re number conditions.Simulations also carried out for different cycle times from normal to small,results indicate that all the values and tendencies of both Nu number and Eu number are varying within a small range and can be ignored within the range of this study.Correlations of Nu number and Eu number for each case of volatile flow conditions are Dresented.
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
2015年第6期1286-1293,共8页
Journal of Engineering Thermophysics
基金
国家重点基础研究发展计划(973计划)项目(No.2013CB228304
No.2013CB228303)
关键词
余热利用
H型翅片
波动流动
数值模拟
回归关联式
waste heat utilization
volatile flow
h-typed fin
numerical simulation
parametric study
