Hello, I hope to get some advice regarding the following questions.

1) In CFX-pre, which domain should be the default domain between fluid domain and solid domain?

2) In CFX-pre, in case that I use the water from the fluid list under the basic settings of default domain's general options, where can I find an area for setting in which I can give the value of water's convective heat transfer coefficient to consider the water's convection? (Actually, in water's material properties offered by cfx's libray, I cannot find the water's heat transfer coefficient for convection...)

3) If the temperature of the subdomain(subarea) in the solid domain should be set at certain initial temperature value (just inital temperature, it is necessary to last), how can I give it? (I tried to set it through the intialisation of the solid domain but that initialisation is for giving the condition for all area of the solid domain instead of subdomain(or subarea)of the solid domain. I also tried to do it using the boudnary condition option for the subdomain but it allows just fixed temperature instead of initial temp. It means that that fixed temperature lasts over the time. However, I need to set the inital temp. at time=0 sec (not constantly lasted temp.))

Thank you so much in advance. Have a good day.

Jaho,

1) When you do not set the domain manually, it will be fluid domain automaticaly.

2) For convection, you can specify the HTC on walls that in contact with water. HTC or heat flux options are provided in the heat transfer model of the wall boundary condition.

3) What type of simulation do you analyse? Steady or transient? In a steady run, temperature will be overwrite during the process of simulation. So, it is meaningless to set a special value for it at time=0 sec. If you want to do this, maybe you can set this subdomain as a domain. Then set the initial temperature on it.

Wish helpful.

Rikio

Hi Rikio, Thank you for your kind help. I still have a question for 2). In my case, through settings for the domain interface, I set 'fluid solid' as interface type, and designated each interface side (side1 and side2)to each corresponding region. Then on the boundary details of each side (side 1 and side2 above)'s boundary conditions, I come to have only 'conservative interface flux' as an option of heat transfer. I wonder this option can deal with the convection... Or my procedure to cover the convection is wrong? If you don't mind, could you please give an answer regarding these? Thank you so much.

Jaho,

A multiphysic problem is being processed? If so, please refer to CFX Help: "If you are running a simulation with ANSYS Multi-field coupling to the ANSYS solver, you will need to create fluid-solid interfaces with the fluid side in CFX and the solid side in ANSYS. Such an interface is actually an external boundary so far as the CFX solver is concerned, as it lies on the boundary of the CFX domain(s). You should create a Boundary Condition, not a Domain Interface, when setting up such an interface. "

In case of flow field simulation, just remove the solid domain.

Rikio

My case is not multiphysic problem... I don't know whether the only solution to deal with this is the Multi-field coupling (Without using the Multi-field coupling , it seems to be solved) Rikio, if you really don't mind, I would like to send you my gtm and cfx files. Then you will understand clearly my problem. Please let me know its availability. Thank you so much, Rikio.

Jaho

[faizan]

hi,

I also have the same problem. Actually In my model there is a solid nozzle with inside nitrogen gas and this nozzle is placed in a cylindrical surrounding also with nitrogen gas. I am unable to establish a flow from nozzle to the surrounding. Only I can see the flow inside the nozzle but i need to see the flow passing outside the nozzle and entering into the surrounding domain.

Can anyone suggest about it?

Thanks in advance