This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.Two phase flow initiates at Onset of Nucleate Boiling, where the first bubble emerges in the
downstream flow direction. Bubble nucleation and growth in microchannel heat sinks is very conspicuous
phase as the growing bubble can completely block the flow cross-section area at high heat flux. Hence,
microchannels are more susceptible to flow boiling instability. In this paper effort has been put to study the
bubble dynamics during bubble growth at nucleation site for microchannel in terms of non-dimensional
energy ratio numbers and their variation from bubble inception until departure. New non dimensional energy
ratio is also proposed, which can be useful to differentiate inertia controlled and thermal diffusion controlled
region during bubble growth at nucleation site
