Toward a generalized correlation for liquid-vapor two-phase frictional pressure drop across staggered micro-pin-fin arrays

In a previous study by the corresponding author and co-worker Mita and Qu (2015) (J. Mita, W. Qu, Pressure drop of water flow across a micro-pin-fin array part 2: adiabatic liquid-vapor two-phase flow, International Journal of Heat and Mass Transfer 89 (2015) 1007-1015), a modified Martinelli-Chisholm type correlation was developed to predict adiabatic water liquid-vapor two-phase frictional pressure drop across an array of staggered circular micro-pin-fins. This work expands on the study in ref. Mita and Qu (2015) and examines whether the correlation is geometry specific or it can be extended to describe a different array configuration. A square micro-pin-fin array were prepared, and adiabatic water liquid-vapor two-phase frictional pressure drop across the array was experimentally investigated. The square pin-fins were 200 microns in side length, 670 microns in height, and 400 microns in both longitudinal and transverse pitches. Two-phase friction multiplier and Martinelli parameter were calculated based on the measured pressure drop as well as a single-phase friction factor correlation developed for the same square array. An excellent agreement was found between the experimental data and correlation predictions despite the distinctive geometrical features possessed by the two sets of micro-pin-fin arrays. The result points to the possibility of establishing the correlation as a generalized one applicable to a broad range of staggered micro-pin-fin array configurations.