Cita:
International Journal of Heat and Mass Transfer, 2009, vol. 52, nº 13-14, p. 3042-3054
ISSN:
0017-9310
DOI:
10.1016/j.ijheatmasstransfer.2009.01.036
Patrocinador:
The authors wish to express their gratitude to Dr. M. Venegas for her useful comments. This work has been partially funded by the Spanish Government Research Grants DPI 2002 02439 and ENE 2005 08255 CO2 02, as well as by the Autonomous Community of Madrid & UC3M through CCG07 UC3M/AMB 3412 project. Their contribution is greatly appreciated
The problem of non isothermal absorption of vapour into freely expanding liquid sheets is addressed in this study. This is done in the context of four models that characterise the coupled heat and mass transfer in the liquid phase: a nonlinear model retaining The problem of non isothermal absorption of vapour into freely expanding liquid sheets is addressed in this study. This is done in the context of four models that characterise the coupled heat and mass transfer in the liquid phase: a nonlinear model retaining the effect of sheet growth, an approximate model for slowly increasing mass flow rate in the sheet, a large Lewis number model and finally, a boundary layer model. These models have been numerically or analytically solved and applied to the comparative analysis of two different working pairs, LiBr H₂O and LiNO₃NH₃, under conditions representative of adiabatic absorption in refrigeration systems. The limits of applicability of each model have been assessed and the sensitivity of the results to the sheet aperture angle, heat of absorption and initial subcooling has also been tested. For equal initial mass fraction and subcooling, the models indicate that Sherwood number and the rate of absorption in laminar expanding sheets for the LiNO₃NH₃solution are always superior to those for the LiBr H₂O solution[+][-]
