A Numerical Study of the Flow and Heat Transfer in the Near Field of a Cylindrical Bubble Moving in a Narrow Channel
A direct numerical simulation is performed of a cylindrical bubble moving in a pressure-driven flow of Novec-649 in a heated channel. The upper wall is an electrically heated metal foil, and the bubble diameter is on the order of the channel spacing. Phase change is not included to isolate the contribution of the liquid motion to the heat transfer. The simulation is performed with FluentTM, the volume-of-fluid method tracks the interface, and the reference frame translates with the bubble. The heat transfer coefficient increases tenfold due to the bubble passage. A lobed structure immediately behind the bubble forms in the surface heat flux, and the surface temperature is depressed over several bubble diameters. A complex horseshoe-like vortex system wraps the bubble and drives the heat flux lobes. The evolution of the heat flux at a point on the surface compares well to predictions of an existing quenching/diffusion model.
Bubble, Forced Convection, Subcooled Flow, Minichannel
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