Comprehensive experimental investigation of two-phase heat transfer and pressure drop with propane in a minichannel

• Two-phase heat transfer with propane is studied in a 0.96 mm diameter circular minichannel.
• Two-phase frictional pressure gradient of propane in a minichannel is reported.
• Available models can be used to predict condensation heat transfer coefficients.
• Higher disagreement is found in the comparison with flow boiling heat transfer coefficients.

The use of hydrocarbons as natural refrigerants inside small diameter channels allows charge minimization and therefore it may be an interesting option in the refrigerating and heat pump technology. The aim of the present experimental work is to fully characterize the thermal performance of propane (R290) in minichannels by measuring frictional pressure drop, condensation and flow boiling heat transfer coefficients inside a circular cross section horizontal minichannel with an internal diameter of 0.96 mm and a rough inner surface. Measurements of frictional pressure drop during adiabatic two-phase flow have been performed at mass velocity ranging between 200 and 800 kg m−2 s−1. Local heat transfer coefficients have been measured during condensation and during flow boiling in the mass velocity range from 100 to 1000 kg m−2 s−1. The present database, including frictional pressure gradient, condensation and vaporization heat transfer coefficients, is compared against predicting correlations available in the open literature.