# Evaopation of droplet

 User Name Remember Me Password
 Register Blogs Members List Search Today's Posts Mark Forums Read

 June 8, 2007, 05:42 Evaopation of droplet #1 wzslj Guest   Posts: n/a Sponsored Links 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!

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post rogerspass FLUENT 1 June 27, 2016 02:12 bohis FLUENT 1 July 10, 2013 04:28 viv05 OpenFOAM 0 February 27, 2010 12:20 Itchie CFX 2 December 13, 2007 03:01 Christian Main CFD Forum 2 February 27, 2007 07:27