Two-phase frictional pressure drop in horizontal micro-scale channels: Experimental data analysis and prediction method development

- The paper presents new experimental data for adiabatic frictional pressure drop in a single microchannel.
- A characteristic dimension discussion to evaluate pressure drop inside microchannels was done.
- Parametric analysis and comparison of the data with predictive methods.
- Proposition of a new predictive method for two-phase pressure drop.
- Proposed method provides accurate predictions of the present and independent databases.

An investigation was conducted on the effects of fluid refrigerant and channel geometry on the frictional pressure drop during two-phase flow inside microchannels. Experimental results for two-phase frictional pressure drop were obtained for the refrigerants R134a, R1234ze(E), R1234yf and R600a in a circular channel and for R134a in square and triangular channels. The experiments were performed for mass velocities from 100 to 1600 kg m−2 s−1, saturation temperatures of 31 and 41 °C, and vapor qualities from 0.05 to 0.95. The experimental data have been analyzed focusing on the effects of the geometry and fluid on the two-phase pressure drop. Then, the data were compared with the most quoted predictive methods from the literature. Based on the broad database obtained, a new method for prediction of the two-phase frictional pressure drop was proposed. The new method provided accurate predictions of the database, predicting 89% of the results within an error band of ±20%.