Convective heat transfer and pressure drop characteristics of near-critical-pressure hydrocarbon fuel in a minichannel

The convective heat transfer and pressure drop characteristics of a kerosene kind hydrocarbon fuel were experimentally investigated in an electrically heated minichannel with an inside diameter of 2.0 mm, in the range of fuel temperature: 25-600 degrees C at near-critical pressures. In the single phase liquid flow, considerable free convection in laminar flow stabilizes the flow at Reynolds number (Re) up to 3600, the heat transfer coefficients can be predicted by Gnielinski correlation with deviations no more than 20.0% at Re > 4000; the adiabatic friction factor well agrees with the Moody diagram and Blasius correlation at laminar and turbulent flow respectively. As fuel temperature approaches the pseudo-critical point, peak and trough in heat transfer coefficients are recorded. First, heat transfer is enhanced by the boiling or pseudo-boiling at the relevant pressures. As fuel temperature increases, heat transfer deterioration takes place, accompanied with acoustic flow instability and peculiarly diabatic pressure drop deduction due to the steep thermodynamic properties. The heat transfer and flow stability are regained as the bulk fuel temperature increases to above the pseudo-critical points. Upon increasing the pressure, the singularities of heat transfer and fluid flow gradually disappear. (C) 2012 Elsevier Ltd. All rights reserved.