Computational investigation of surface enhancements in jet impingement boiling*

Numerous studies identify jet impingement boiling as an effective method to transfer energy in high heat flux applications. While most experimental studies so far focus on flat surfaces, there is some evidence that surface enhancements improve the Critical Heat Flux (CHF). Local dry-out is a consequence of stagnating flow initiated by flow obstruction. However, the influence of stagnating flow on CHF due to surface augmentation is an unanswered question. Here, we numerically investigate the effect of surface augmentation in the form of grooves and pin fins, particularly to understand the effect of surface configuration and layout on heat transfer, phase change, and turbulent exchange between the two phases. Heat transfer is predicted using the Eulerian multiphase framework in conjunction with the Rensselaer Polytechnic Institute (RPI) boiling model. Numerical results correspond well with reported surface enhancements subjected to single and array of round jets. A 2D flow boiling study over consecutive micro-grooves suggests that groove dimensions can prevent local dry-out due to the manipulation of flow patterns. A strong correlation is found between flow Reynolds number, average turbulent kinetic energy, and Heat Transfer Coefficient (HTC). A 3D parametric study suggests that surface augmentation can improve heat transfer at the stagnation region if local dry-out is avoided.