南京航空航天大学学报（英文版）2026，Vol.43Issue(1)：95-109,15.DOI:10.16356/j.1005-1120.2026.01.008
封闭腔体内双加热元件热羽流的传热特性与流动转变
Heat Transfer and Flow Transitions of Thermal Plumes Generated by Double Heating Elements in a Confined Enclosure
摘要
Abstract
The buoyancy-induced flow constitutes a core scientific issue for thermal management of electronic devices and thermal design of energy systems,where accurate characterization of flow and heat transfer is essential to improve thermal efficiency.In this work,buoyancy-induced flow above two heating elements flush-mounted at the bottom of a square enclosure containing air is numerically investigated over a range of Rayleigh numbers(0＜Ra≤1.5×108),with a focus on equal and unequal heat flux conditions under a constraint of constant total thermal energy input.Distinct flow transitions are observed in both cases,leading to the identification of three flow regimes:Steady,periodic unsteady,and chaotic unsteady.Two types of periodic flows are distinguished,in which the first is a periodic flow dominated by a fundamental frequency(FF)and its integer-multiple frequencies(INTMF),while the second is a more complex periodic flow featuring FF,INTMF,and their sub-harmonics.The transitions between these regimes are affected by the relative heat flux of the two heaters.When the heat flux of the two heaters is unequal,the range of Rayleigh numbers corresponding to periodic flow is suppressed.It is also found that the time-averaged maximum temperature of the strong heater increases more rapidly with Ra,while that of the weak heater increases more slowly,reflecting the interaction between buoyancy-driven flow dynamics and asymmetric heat input.Analysis of the time-averaged Nusselt number demonstrates that heat dissipation from the isothermal walls remains roughly equivalent,even when the heat flux of the two heaters differs by a factor of two.These findings highlight the critical roles of Rayleigh number,the number of heaters,and the heat flux ratio of the heaters in determining heat transfer and flow characteristics for buoyancy-driven convection systems,providing important theoretical support and design references for engineering scenarios such as electronic devices and design of new energy systems.关键词
自然对流/热羽流/双加热元件/流动转变/传热效率Key words
natural convection/thermal plume/double heating elements/flow transitions/heat transfer分类
航空航天引用本文复制引用
王莹,许哲健,杨文,马鑫宇..封闭腔体内双加热元件热羽流的传热特性与流动转变[J].南京航空航天大学学报（英文版）,2026,43(1):95-109,15.基金项目
This work was supported by the Tian-jin Education Commission Research Program Project(No.2024KJ105). （No.2024KJ105）
