A generalized correlation for two-phase forced flow heat transfer—second assessment

Abstract

A generalized correlation for two-phase forced flow heat transfer (nucleate boiling and vaporization) is suggested which is valid for vertical and horizontal channels with a fully wetted perimeter. It represents, with a mean absolute deviation equal to 14.4%, experimental data for 21 different liquids (water, organic liquids, freons and cryogens) in the following ranges of the main parameters: pressure, 0.61–196 bar; heat flux density, 10−8 × 10 6 W m −2; mass flow rate, 5.6–6240 kg m −2 s −1; channel diameter, 0.47–74.7 mm. It has been found that both the nucleate boiling and the vaporization heat transfer intensity depend on the thermal conductivity of the channel wall material. It is demonstrated that nucleate boiling heat transfer is described by a single equation in dimensionless variables containing an individual constant for each of the four groups of fluids (water, organic liquids, freons and cryogens). Vaporization heat transfer is described by a single equation with a constant universal for all the fluids.