Abstract
The application of two-phase flow in microchannel needs further research to achieve a more stable and highly-performed heat sink. Utilizing self-rewetting fluid is one of the promising ways to minimize the dryout area, thus increasing the heat transfer coefficient and critical heat flux (CHF). To investigate the heat transfer performance of self-rewetting fluid in microchannel flow boiling, a numerical investigation is carried out in this study utilizing the VOF method, phase-change model and continuum surface force (CSF) model with surface tension versus temperature. Athree-dimensional numerical investigation of bubble growth and merger is carried out with water and 0.2%wt heptanol solution. The single bubble growing cases, two x-direction/y-direction bubbles merging cases and three bubbles merging cases are conducted. Since the bubbles never detach the heated walls, the dryout area and regions nearby the contact line with thin liquid film dominated the heat transfer process during the bubbles' growth and merger. The self-rewetting fluid is able to minimize the local dryout area and achieve the larger thin liquid film area around the contact line due to the Marangoni effect and thermocapillary force, thus result in higher wall heat flux when compared to water. The two x-direction bubbles merging case performed best for heat transfer in the microchannel, in which self-rewetting fluid achieves heat transfer enhancement for over 50 percent compared with water.
Numerical investigation of volume of fluid and level set interface capturing methods for bubble growth and detachment
