High mass flux flow boiling and critical heat flux in microscale

► Flow boiling and CHF experiments were performed in microtubes at high mass fluxes. ► CHF has a stronger relationship with mass flux compared to the trend in literature.
- Heated length over diameter ratio has a significant effect on CHF. ► Microtube diameter has an inverse relation with CHF. ► New CHF correlations were developed using Least Squares Method.