high temperature object in water

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 August 27, 2004, 14:12 high temperature object in water #1 mike Guest   Posts: n/a hi, i'd like to simulate high temperature (high enough to vaporize water) object enters water. could someone tell me some references? what issues i have to look at? numerical difficulties? etc. ? thanks a lot, mike

 August 30, 2004, 03:29 Re: high temperature object in water #2 george Guest   Posts: n/a - coupling of heat conduction in body with heat transfer at surface - heat transfer at surface: evaporation of water: what kind of boiling ? do you want to model it (e.g heat transfer relation) or to simulate it (cfd for unsteady two phase flow with phase transition) ? - try "quenching" to get further references on physics

 August 30, 2004, 12:33 Re: high temperature object in water #3 mike Guest   Posts: n/a george, thanks for your reply. my problem involves large excess temperature so it's in the stable film boiling regime. i'd like to simulate the multiphase flow using cfd. i don't know where to start since there's so many things involved. i guess i should look into where/how to simplify the process first before taking on the whole thing. any suggestion? mike

 August 31, 2004, 05:45 Re: high temperature object in water !!! #4 a. Guest   Posts: n/a Hi, I was thinking about solving the flow in a pipe, which walls are suddenly extremely heated. SO I could expect boiling. Unfortunately, I cannot find any good book about boiling, or an example of such a solution. COuld you please HELP?

 August 31, 2004, 07:45 Re: high temperature object in water #5 george Guest   Posts: n/a - if you want to simulate the whole thing, you have to consider the 2phase flow with phase transition - there you have a continuous interface (between vapor and liquid) so some vof or level-set method could be used. extra care about what is happening at the interface : the physics of the phase transition liq-> vap and vap->liq should be considered - check the physics what the interface is doing: for very high subcooling and very high flow velocities you can assume smooth interface, if not you have instabilities (waves and ripples) you have to consider. is the problem transient ? are there any parts of the problem that can be assumed steady state ? - for how to simplify your problem maybe check the more traditional, analytical engineering type approaches to your problem or look in related areas. some hints: metallurgy: quenching , film cooling. nuclear: LOCA (loss of coolant accident), cooling of hot fuel rods. heat transfer (equipment): convective boiling in and around tubes - there was some cfd done for film boiling: V.K. DHIR (in ASME J.Heat.Trans (some 5-3 years ago), TRYGGVASON (did some computations with his level set method I recall) (although the info might be somewaht outdated now) (it was about the deformation instability of the interface) good luck in dealing with a very nontrivial problem george

 September 1, 2004, 12:11 Re: high temperature object in water !!! #6 mike Guest   Posts: n/a you could look into: 1) Adrian Bejan, convection heat transfer 2) Van Carey, liquid-vapor phase-change phenomena good luck.