please help me if u can how to model the natural convection using fluent thanks alot in advance sihu

Hey Man:

My work is exactly in this situation. what do you want to know?

Best Regards, Farid,

i want to model flow and heat transfer inside rectangular channel and my fluid properties is like water properties and i have the small temperature difference so i want to modell considering the buoyncy or the natural convection using fluent i hope u help thanks alot in advance Mr Syed

Hey man Please send me your grid and say me exactly what's your problem. The mixed convection or Natural convection? What is your Rayliegh number? at the end what is your Prandtl number? Best Regards, Farid,

i use to model mixed convection density=996 kg/m3,thermal conductivity=0.61 W/mk and specific heat=4184 J/kgk , viscosity = 0.00088 kg/ms and the velocity=0.0073 m/sec and temperature difference is 15k and the geometry is rectangular 400mm*40mm*200mm this is the data thanks in advance brathor Syed Fareed and i wait for ur help

Hey Man, Please you must activate in "operating condition" the "gravity". Then enter the gravity (0. for x direction,-9.8 for y directin, 0 for z direction). I assumed the y direction is parallel to gravity direction. Then in "Materials" select "Boussinesq" option in "density". By selecting this option your density changes to zero that you must enter 1.225. After that in this window at the bottom by moving your mouse you must enter the value of "Thermal Expansion". by this works the fluent run the test case for free convection. I hope that works. At the end as you know your problem is mixed convection and you must set the Rayliegh number (or Grashohph number), Prandtl number and Reynolds number. I mean you must be careful to enter the all properties in the material section and velocity inlet value. If you have any problem please contact me.

Have a good weekend, Best Regards, Farid,

iam trying but the solution does not converge and i have strange velocity profile and i got high temperaure so please send me in my e mail the explanation in detail thanks very much Syed Farid Hossain e mail sihatt2002@yahoo.com thanks again for your attention