Forced convection in the wakes of sliding bubbles

7th European Thermal-Sciences Conference

Meehan, O'Reilly^1,2 ; Donnelly, B.^2 ; Persoons, T.^1 ; Nolan, K.^2 ; Murray, D.B.^1

Dept. Mechanical and Manufacturing Engineering, Trinity College Dublin, Ireland^1

Thermal Management Research Group, Efficient Energy Transfer (ET) Department, Bell Labs Research, Blanchardstown Business and Technology Park, Snugborough Rd, Dublin 15, Ireland^2

关键词: Convective heat transfer;    Flux enhancement;    Hairpin vortices;    Heat transfer rate;    Inclined surface;    Surface temperatures;    Thermal boundary layer;    Wake structures;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/745/3/032117/pdf
DOI  :  10.1088/1742-6596/745/3/032117

来源: IOP

【 摘 要 】

Both vapour and gas bubbles are known to significantly increase heat transfer rates between a heated surface and the surrounding fluid, even with no phase change. However, the complex wake structures means that the surface cooling is not fully understood. The current study uses high speed infra-red thermography to measure the surface temperature and convective heat flux enhancement associated with an air bubble sliding under an inclined surface, with a particular focus on the wake. Enhancement levels of 6 times natural convection levels are observed, along with cooling patterns consistent with a possible hairpin vortex structure interacting with the thermal boundary layer. Local regions of suppressed convective heat transfer highlight the complexity of the bubble wake in two-phase applications.