TY - JOUR
T1 - Heat transfer model for evaporation in microchannels. Part II
T2 - Comparison with the database
AU - Dupont, V.
AU - Thome, J. R.
AU - Jacobi, A. M.
PY - 2004/7
Y1 - 2004/7
N2 - In part I, a three-zone flow boiling model is formulated to describe evaporation of elongated bubbles in microchannels. The heat transfer model describes the transient variation in local heat transfer coefficient during the sequential and cyclic passage of (i) a liquid slug, (ii) an evaporating elongated bubble and (iii) a vapor slug. In this part, the time-averaged local heat transfer coefficient is compared to experimental data taken from seven independent studies covering the following seven fluids: R-11, R-12, R-113, R-123, R-134a, R-141b and CO2. The 1591 test data cover tube diameters from 0.77 to 3.1 mm, mass velocities from 50 to 564 kg/m2s, pressures from 124 to 5766 kPa, heat fluxes from 5 to 178 kW/m2, and vapor qualities from 0.01 to 0.99. The new model predicts 67% of the database to within ±30%. The new model illustrates the importance of the strong cyclic variation in the heat transfer coefficient and the strong dependency of heat transfer on the bubble frequency, the minimum liquid film thickness at dryout and the liquid film formation thickness.
AB - In part I, a three-zone flow boiling model is formulated to describe evaporation of elongated bubbles in microchannels. The heat transfer model describes the transient variation in local heat transfer coefficient during the sequential and cyclic passage of (i) a liquid slug, (ii) an evaporating elongated bubble and (iii) a vapor slug. In this part, the time-averaged local heat transfer coefficient is compared to experimental data taken from seven independent studies covering the following seven fluids: R-11, R-12, R-113, R-123, R-134a, R-141b and CO2. The 1591 test data cover tube diameters from 0.77 to 3.1 mm, mass velocities from 50 to 564 kg/m2s, pressures from 124 to 5766 kPa, heat fluxes from 5 to 178 kW/m2, and vapor qualities from 0.01 to 0.99. The new model predicts 67% of the database to within ±30%. The new model illustrates the importance of the strong cyclic variation in the heat transfer coefficient and the strong dependency of heat transfer on the bubble frequency, the minimum liquid film thickness at dryout and the liquid film formation thickness.
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U2 - 10.1016/j.ijheatmasstransfer.2004.01.007
DO - 10.1016/j.ijheatmasstransfer.2004.01.007
M3 - Article
AN - SCOPUS:2442526598
SN - 0017-9310
VL - 47
SP - 3387
EP - 3401
JO - International Journal of Heat and Mass Transfer
JF - International Journal of Heat and Mass Transfer
IS - 14-16
ER -