摘要
应用层流模型及湍流模型数值模拟方法,结合两种边界条件处理方法分别对两种纵向内翅片管内的流动与传热性能进行了研究,其中湍流计算采用可实现k～ε两方程模型。将两种计算模型数值结果与实验结果进行了对比,结果表明:湍流模型数值模拟结果较层流更接近于实验值,同时发现两种内翅片管内流动从层流发展到湍流的临界雷诺数远小于传统光管的临界雷诺数。针对湍流模型模拟结果分别拟合出了两种内翅片管Nu-Re及f-Re的关联式,拓宽了实验数据的应用范围;通过场协同原理定量对比分析了两种内翅片管强化换热机理,研究表明纵向突起内翅片管的场协同程度好于纵向平翅片管,起到强化传热的作用。
With a laminar flow model and a turbulent flow model-based numerical simulation method being adopted and in combination with two kinds of boundary-condition treatment methods,a study has been conducted respectively of the flow and heat transfer performance of two types of longitudinally and internally finned tubes.During the study,a realizable k-ε two equation model was used for the turbulent flow calculation.The numerical simulation results obtained from the two calculation models were compared with test results.It has been found that the simulation results obtained from the turbulent flow model are closer to the test values than those obtained from the laminar flow model.In the meanwhile,it has also been found that the critical Reynolds Number for the flow in both internally finned tubes when developing from a laminar flow to a turbulent one is far less than that for the traditional bare tube.In the light of the simulation results obtained from the turbulent flow model,correlation formulae were obtained through a fitting for the two types of internally finned tubes of Nu-Re and f-Re respectively,thus extending the applicable scope of the test data.Through a field synergy principle,a contrast analysis of intensified heat exchange mechanism for both types of internally-finned tubes was quantitatively conducted.The results of the study show that the field synergy degree of longitudinally-ridged and internally-finned tubes is better than that of longitudinally flat-finned tubes,thereby playing a role of intensified heat transfer.
出处
《热能动力工程》
CAS
CSCD
北大核心
2008年第5期527-530,共4页
Journal of Engineering for Thermal Energy and Power
关键词
内翅片管
强制对流
传热特性
数值模拟
internally-finned tube,forced convection,heat transfer characteristics,numerical simulation
