Research Projects

The proposed study is focused towards integrating the potential of phase change phenomena occurring in one of the fluids (referred to as secondary fluid (high volatile liquid)) of an immiscible mixture of fluids towards inducing turbulent mixing in the primary (lighter) fluid, which dissipates heat under the regime of natural convection. The fact that local turbulence in the primary heat dissipating fluid is being created due to the upward moving vapor chunks, produced as a result of heating of the high volatile (heavier) fluid above its saturation temperature, which in turn undergoes phase change, one may achieve significant heat transfer enhancement in a complete passive mode under natural convection regime itself. Important bubble dynamic parameters that ultimately govern the phase change process and the associated whole field temperature distributions in the vicinity of the heated lower plate as well as around the growing vapor bubble have been proposed to be simultaneously mapped using infrared thermography and refractive index-based imaging techniques. In this direction, gradients-based imaging technique is proposed to be employed to simultaneously visualize the bubble growth as well as the space and time resolved temperature field for calculation of relative contributions of different heat transfer mechanisms. In order to accurately predict the microlayer thickness at different stages of bubble growth process, the transient evolution of microlayer is proposed to be mapped using laser-based thin film interferometry technique. IR camera would be used in conjunction with the rainbow schlieren imaging method and thin film interferometer to map the real time, space-resolved temperature distribution field on the heated substrate surface on which boiling of the secondary fluid takes place. One of the primary objectives of the proposed work is to carry out the performance evaluation of the interfacial and dynamical behavior of the interface of two immiscible liquid layers with higher density fluid undergoing phase change (through nucleate boiling) at the bottom plate and condensation at the top (cold) plate and the associated heat transfer enhancement (caused due to turbulent mixing in the primary fluid) in a differentially-heated closed cavity under the realm of natural convection. Efforts would be made to develop a detailed understanding of the plausible mechanisms through which the high volatile liquid influence some of the fundamental sub-processes/parameters, such as bubble departure frequency, microlayer growth and its real time dynamics, growth and development of superheated layer, dynamic contact angle etc. of nucleate boiling phenomena for various height of high volatile fluid.