Three-Dimensional Jet Impingement Boiling on a Flat Plate

Abstract

The non-axisymmetric three-dimensional boiling flow of a<br><br>planar impinging jet on a hot flat plate has been investigated by<br><br>using similarity solution approach, taking into account<br><br>additional diffusivity terms in momentum and energy equations<br><br>as a result of bubble-induced mixing in flow. The free jet stream<br><br>along z-direction impinges on the surface and produces a flow<br><br>with different velocity components. The governing equations<br><br>have been transformed into ordinary differential equations by<br><br>introducing appropriate similarity variables and an exact<br><br>solution has been obtained for three-dimensional flow boiling<br><br>problem for the first time. The total heat flux, transferred from<br><br>the surface to the flow has been estimated as summation of the<br><br>single-phase heat transfer due to forced convection and the<br><br>nucleate boiling heat flux due to bubble-induced diffusion. The<br><br>effects of the velocity components ratio (  ) and the ratio<br><br>between the maximum total diffusivity to the molecular<br><br>diffusivity ( + ) on the flow field and heat transfer<br><br>characteristics have been obtained and discussed and illustrated<br><br>graphically. Also, a comparison of the predicted heat flux has<br><br>been made with previously published experimental data. A<br><br>reasonable accuracy of the results in the range of -32% to 0.5%<br><br>with average deviation of 15.7% from the experimental data for<br><br>three-dimensional simulation, and in the range of -35% to -<br><br>3.5% with average deviation of 19% for two-dimensional case,<br><br>simplified simulation of the three-dimensional problem, has<br><br>been obtained. As expected, the average deviation values show<br><br>relatively more accurate results for the three-dimensional<br><br>simulation than the two-dimensional one because of being<br><br>closer to the experimental conditions.