|
[Sponsors] |
June 8, 2007, 05:42 |
Evaopation of droplet
|
#1 |
Guest
Posts: n/a
|
Hi!freinds,I was studying on the mathematical simulation of the droplet drying. The mathematical expression of the droplet's diameter is d(rd)/dt=-km*M1*(pvs-pv&infin/(R*ρl*Tav) (1) drying conditions: r0=0.00075mm, T∞(environment temporature)=60℃ and RH=80% km=Sh*Dg/(2*rd) (2) In equation(1): the molar mass of the water M1=0.0018kg/molar; R(gas constant) = 8.314; ρ1=1000kg/m3; Tav(temperature difference between the surface anfd the surroundings)=40℃ In equation(2): Dg(the diffusion coefficient of water vapor)=1.32e-5 Sh=2+2*(rd/r0)^0.5 (3) Questions are: The vapor pressure of the air pv∞(T∞=60℃)=RH*ps∞(saturated vapor pressure),=15936pa,but the saturated vapor pressure of droplet surface (T=20℃)=2331pa<15936pa. The temperature of droplet rise until the saturated vapor pressure of droplet surface is greater than the gas vapor pressure. Then the droplet starts evaporating. But the droplet diameter by the simulating is smaller than the experiment results, why?
Thanks! |
|
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
droplet impact on a dry surface.... VOF again | rogerspass | FLUENT | 1 | June 27, 2016 02:12 |
droplet falling - VOF | bohis | FLUENT | 1 | July 10, 2013 04:28 |
DieselFoam Droplet Temperature Issues - OF 1.6 | viv05 | OpenFOAM | 0 | February 27, 2010 11:20 |
Importance of droplet size | Itchie | CFX | 2 | December 13, 2007 02:01 |
Droplet Evaporation | Christian | Main CFD Forum | 2 | February 27, 2007 06:27 |