Prediction method for flow boiling heat transfer in a herringbone microfin tube
Artikel i vetenskaplig tidskrift, 2005

Based on experimental data for R134a, the present work deals with the development of a prediction method for heat transfer in herringbone microfin tubes. As is shown in earlier works, heat transfer coefficients for the investigated herringbone microfin tube tend to peak at lower vapour qualities than in helical microfin tubes. Correlations developed for other tube types fail to describe this behaviour. A hypothesis that the position of the peak is related to the point where the average film thickness becomes smaller than the fin height is tested and found to be consistent with observed behaviour. The proposed method accounts for this hypothesis and incorporates the well-known Steiner and Taborek correlation for the calculation of flow boiling heat transfer coefficients. The correlation is modified by introducing a surface enhancement factor and adjusting the two-phase multiplier. Experimental data for R134a are predicted with an average residual of 1.5% and a standard deviation of 21%. Tested against experimental data for mixtures R410A and R407C, the proposed method overpredicts experimental data by around 60%. An alternative adjustment of the two-phase multiplier, in order to better predict mixture data, is discussed.

Correlation

R134a

R410A

R407C

Microfin tube

Geometry

Heat transfer

Mass transfer

Experiment

Författare

Sven Wellsandt

Chalmers University of Technology

Lennart Vamling

Industriella energisystem och -tekniker

International Journal of Refrigeration

0140-7007 (ISSN)

Vol. 28 912-920

Ämneskategorier

Energiteknik

Strömningsmekanik och akustik

DOI

10.1016/j.ijrefrig.2005.01.009