i have simulate the flow of water in tundish in steady and isothermal case, and i want to get rtd curve i proceded by: 1-define-species 2-monitoring the concentration at the outlet. my problemes are: 1-how to put the values of material mixture(density,cp,.....) 2-i want to remove energy equation because appeares when put incompressible-ideal-gas in density of mixture. 3-should i initialise the flow of water 4-how to calcule the mass fraction of dye for 3s(density-35g/l,diffusivity-3e-8)

best regards

in my opinion, the solution for your problem are

1. properties of mixture can be set in the panel of materils. be sure to select the mixture as you defined.

2.you can deselect the equation of energy in 'solve-controls-solution' menu order.

3. if you want to calculate the species transportation only without interaction with fluid, the flow of water need not to be initilized. if you do, error results maybe gotten.

4. you can save the case and data fils at the moment say, 3s. then you can check the mass fraction of dye.

my blog: http://richard001.blogspot.com/, you are welcome to leave a comment.

thankyou mr richard but you hav'nt tell me how to put properties of mixture example: density,cp,...... -mr richard deselect energy in solve control,fluent d'ont remove energy equation but remove only the calcul of temperature . -i want to calcul the transport of dye in flow of water previously calculated ,thus i must initialise the flow of water. -mr richard how to calcule the mass fraction of dye. mr richard i am new in fluent iwant to simulate the water in tundish by using the dye solution for calculating rtd , i want to confirm my procedure ,can you helpme by sending me the solution of my problemes

i have visited your site but i have tried to give comment but i can't .i showed the geometry of tundish , there is very good mesh.

Thank you very much indeed fro browsing my blog! now, I am reading a case of mine for RTD curves.

for the density, I just select the 'volume weighted mixing law' option. for the cp, it is constant since it has no or slight effect on RTD ( in your case you even do not consider the energy equation). the same condition for thermal can be employed. for the viscosity and mass diffusivity, you can use UDF or just set it as constants with little influence on the results.

sorry for the inconvenience to you as to the energy euqation problem, you can untick the energy in menu'define-models-energy'. Usually, it is ticked by default if you choose the species transportation. however, I don't know its effect on the result. maybe you can try and make a comparision. Consequently, in the solution selection, there is no temperature option.

I am now unclear why you must initial your water flow result when you calculate dye trasportation. do you mean you will calculate the flow and dye's transportation together again. it should be emphasized that it is mass fraction at the monitered outlet.

you are welcome if you have a confused question. we can discuss it together. moreover, I will post some experiences and tips in my blog about my continuous work. wish you browse it if you will and have time. it is just a beginning.

my blog: http://richard001.blogspot.com/

are you here richard

mr richard ,i have simulate the flow of water in steady and isothermal case and i want to find the rtd curve by injecting the dye as pulse in flow of water previously calculated .my problemes are: when i put incmpressible ideal gas in a density of mixture i can't remove the equation of energy . mr richard we must init the flow of water before calculting rtd. finally can you help me how to put in properties of materials for mixture and how to remove the energy equation best regards

may be you should set a liquid tracer as experiments. if it is gas, it is not only hard but a incorrect result. try again!

yes i want to inject tracer liquid

if you have problem, please do not hesitate to let me know. regards

my blog： http://richard001.blogspot.com/

i repeat , my problemes are situated in : 1-how to put the properties of mixture in material panel. 2-how to remove the energy equation because i work in isothermal case.the probleme is caused when i work with the species model(transport)(define species)

please look for the answer in my post! maybe it is helpful.

1-can you please clear more and repeat and confirm to me how to put in properties of mixture in material panel (density,cp,.......).(all) 2-how to remove the energy equation.(what is the probleme.

i have not understand your reponse

can you give me the solution step by step best regards chankhar

cn any one help me

help me richard

a. define liquid tracer in materials panel b. define a mixture template for instance, tracer-water c. set the properties of mixture

1. density, 'volume weighted mixing law'

2. cp, constant

since it has no or slight effect on RTD ( in your case you even do not consider the energy equation).

3. thermal, constant.

4. viscosity and mass diffusivity, constants or by UDF d. energy euqation problem, untick the energy in enu'define-models-energy'. Usually, it is ticked by default if you choose the species transportation. however, I don't know its effect on the result. maybe you can try and make a comparision. Consequently, in the solution selection, there is no temperature option.

if you have problem with this procedure, please check it again first and let me know then. thanks. you also can send a mail to me simply so that I can send you more detail in an enclosed file.

best regards Richard

1-can you please clear more and repeat and confirm to me how to put in properties of mixture in material panel (density,cp,.......).(all) 2-how to remove the energy equation.(what is the probleme.

i have not understand your reponse

can you give me the solution step by step best regards chankhar

my mail is :chankhar@caramail.com

mr richard i remercie you for your help but : 1-you have told me why i must initialize the flow of water,mr richard for calcul the rtd ,i read a lot of works which all initialize the flow of water in tundish. 2-i have a dye with diffusivity of 3e-8m2/s2 and density of 35g/l, my question is how to put the diffusivity of mixture best regards

I have sent you an email. can you send me a piece of this kind of work? it seems that your dye density is too small while salt solution is commonly used as tracer. have you used this kind of dye in your physical experiments? how about the result?

best regards

richard