Numerical model to estimate subcooled flow boiling heat flux and to indicate vapor bubble interaction
Journal article, 2021

There are numerous technical applications where hot components, with uneven temperature distribution, require cooling. In such applications, it is desired to provide efficient local cooling of the hot spots, while avoiding unnecessary over-cooling of the other regions. Such an approach, known as precision cooling, has several advantages. In addition to the fact that it reduces the effort for cooling, it limits the unintended heat lost to the cooling medium. In liquid cooled systems, such as Internal Combustion Engines (ICE), subcooled flow boiling offers immense potential for precision cooling. The primary challenges in extracting this potential are understanding the complexities in the subcooled flow boiling phenomenon and estimating the risk of encountering film boiling. The present study introduces a numerical model to estimate the wall heat flux in subcooled flow boiling and the model includes a mechanistic formulation to account for vapor bubble interaction. The formulation for vapor bubble interaction serves two purposes: (a) blends two well-established models in the literature, one in the isolated bubbles regime and other in the fully developed boiling regime, to estimate the wall heat flux; and (b) provides information to limit boiling in order to not encounter film boiling. The results from the new model are validated with two different experiments in the literature and the wall heat flux estimated by the model is in agreement with experimental results and responsive to different input parameters, such as bulk velocity, operating pressure and inlet subcooling. The new model requires only input of local flow quantities and hence implementation in Computational Fluid Dynamics (CFD) is straightforward.

Boiling regimes

Precision cooling

Active nucleation site density

Vapour bubble interaction

Subcooled flow boiling

Author

Sudharsan Vasudevan

Chalmers, Mechanics and Maritime Sciences, Fluid Dynamics

Sassan Etemad

Volvo Cars

Lars Davidson

Chalmers, Mechanics and Maritime Sciences, Fluid Dynamics

Gonzalo Montero Villar

Chalmers, Mechanics and Maritime Sciences, Fluid Dynamics

International Journal of Heat and Mass Transfer

0017-9310 (ISSN)

Vol. 170 121038

Subject Categories

Applied Mechanics

Energy Engineering

Fluid Mechanics and Acoustics

DOI

10.1016/j.ijheatmasstransfer.2021.121038

More information

Latest update

3/16/2021