Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7053980 | International Journal of Heat and Mass Transfer | 2018 | 10 Pages |
Abstract
A mechanistic pressure drop model is proposed in this paper for condensation in horizontal smooth round tubes in order to account for the non-equilibrium effects. The model makes use of a flow regime map and void fraction correlation as well as a mechanistic heat transfer model that are all developed for condensation of superheated vapor in a vapor-compression system. The model provide seamless transition between single-phase and two-phase regions including the superheated, condensing-superheated, two-phase, condensing-subcooled and subcooled regions. Diabatic flow visualizations are used to analyze the effects on pressure drop from the formation of waves. An enhancement factor to represent the frequency and magnitude of the waves is established using Kelvin-Helmholtz and Rayleigh-Taylor instability. The two-phase pressure drop is modeled based on the single-phase pressure drop correlations, the flow regimes, void fractions as well as the enhancement factor. Data obtained from R134a, R32, R1234ze(E), R1233zd(E) and R245fa with mass fluxes from 100â¯kgâ¯mâ2 sâ1 to 400â¯kgâ¯mâ2 sâ1 and heat fluxes from 5â¯kWâ¯mâ2 to 15â¯kWâ¯mâ2 inside two different tubes of 4 and 6â¯mm are used to validate the model.
Keywords
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Fluid Flow and Transfer Processes
Authors
Jiange Xiao, Pega Hrnjak,