Heat Flux Enhancement in Microstructure System

Pool boiling heat transfer mechanism is a general phenomenon for understanding the heat flux enhancement. In this case, micro/nano surface modification over the plain surface play vital role for enhancement of heat flux. Diversity of micro/nanostructures has been built on plain surfaces, which have guided to improvement in the heat transfer. Particularly, Development of nanowires, nanotubes and micro/nanoparticles deposition; regular micro/nano-geometries (pillars, fins, and microchannels) have already done. Modified surface affects the heat flux which can be classified into two groups: surface topography and the number density. Microstructure or nanostructure modified surface influences the surface wettability which has a significant role in enhancing heat transfer. In this work, the significance of surface modification with micro-structures in heat transfer enhancement has been studied. Two types of metal-metal oxides were selected such as Ti-TiO 2 and Al-Al 2 O 3 for designing geometry. Constant Heat Flux and HTC were applied and the change in surface temperature has been determined. Primarily, Ti metal plain surface showed 30.4 °C as well as Al metal plain surface showed 29.9 °C which is lower than Ti plain surface. Moreover, microstructure surface modification with varying height showed better result. Ti-TiO 2 showed 28.9 °C as well as Al-Al 2 O 3 showed 28.9 °C for 19 by 19 matrixes which is comparatively lower than plain metal surface. Hence, micro modified surface with increasing microstructure density as well the aspect ratio of those structures tends to alter the heat transfer behavior. Maximum heat flux observed 31 W/cm 2 by Ti–TiO 2 and Al -Al 2 O 3 by 35 W/cm 2 . For both cases, enhancing surface area enhance the heat flux. On the other hand, increasing the wall superheat influence the heat flux enhancement.