ANSYS Fluent Tutorial: Natural Convection Heat Transfer 2D Transient Analysis on a Solid Cylinder
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- เผยแพร่เมื่อ 29 มิ.ย. 2019
- Description:
In the Current tutorial, natural convection heat transfer has been modeled, for a solid aluminum cylinder. The cylinder has been kept in a rectangular chamber. The cylinder wall temperature is 500 K, whereas the surrounding air temperature is 300K, this temperature difference causes a natural convection Heat transfer between the cylinder surface and the surrounding air. This Heat Transfer has been analyzed for an unsteady(transient) case for a time period of 60 seconds. The detail variation of temperature along with time has been captured as solution animation.
What will you learn from this tutorial?
- Creating the geometry for 2D analysis.
- Meshing
- Transient analysis modeling.
- Creation of the Solution animation - วิทยาศาสตร์และเทคโนโลยี
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Thank you for the tutorial. Super helpful !
most welcome🙂🙂🙂
So much easier to use than FlexPDE. Wished we had this in our company, could do so much more.
thank you for sharing your knowledge :) respect
most welcome, Thank you for your love for our youtube channel.
Wow.... you save me!! It is really wonderful lecture. Thank you!!!
You are most welcome.
Hi, I've seen some wonderful videos made by you. They are really good. But in this video, I wonder why haven't you used 'solid time step'? I believe during conjugate heat transfer, one has to use a 'solid time step'. Correct me if I'm wrong.
Thank you.
Thank you ver much, keep up with good work =)
Thank you
u r incredible man thk you soo much
thank you 🥰🥰🥰
thanks sir for sharing your knowledge.
most welcome, Thank you for your love towards our youtube channel.
Hey, hi! Do you know why Fluent created that B.C. named cylinder_wall-shadow? You named the cylinder wall earlier, so I got confused why the software created another B.C. related to that wall. I was thinking that maybe it is because you named using the cylinder wall, but there's the wall from the fluid domain too that corresponds to the same points in space... maybe it is that, right?
Yes, generally a shadow wall is generated if there are two different cellzone, if you name the one face of a cellzone then at the other cellzone adjacent to this cellzone will create a shadow wall.
Respect sir!
thank you
Thank you for the tutorials, very helpful.
In this one i had a problem in the results of the convection. The heat flux is "trapped" into the cylinder. I did not impose any BC to the walls, since the option "system coupling" wasn't available. How can i solve it?
Thank you a lot!
You need to be very careful while creating the sketch, . You should create the geometry in different sketch for cylinder & fluid domain.
Very helpful .. Thank you !! I have a question, regarding the boundary conditions of the walls , Why do we set "via system coupling" in the thermal condition
in via system coupling the wall will be heated as per the heat received from the cylinder. If you take any other BC ,the wall will as act as one of the input BC , but in system coupling it will take the tempr from the other region.
@@AnsysTutor Im facing a problem where the BC "Via System Coupling" is not highlighted. What am I supposed to do then?
@@AnsysTutor Hi, Not sure if I agree. When you select the system coupled option and press OK it shows a message in the console: that the type is not applicable and it is skipping it. If you open it again you will see that nothing has changed and your boundary condition is a zero heat flux.
@@renatoamorimtorres7915 Did you solve this problem? I have same problem....
Thank you for your sharing. I have a question, Can I know what is solver which used in this video? I know that there are three popular methods in CFD... RANS, LES, DNS... etc. I want to know what kinds of solvers in ANSYS FLUENT
these three methods are for turbulence modeling, as you can see in the current video we have not selected any flow model.
Thank you for tutorial!
I got this error message "Selected option 8 for Thermal BC Type for thread bottom_wall is not applicable, so skipping it." when I tried to change Boundary conditions of wall to "via System Coupling"...what is wrong?
Also what is difference of compute from "bottom wall"?
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I got all answers from comments.
Thank you!
Hi. Your video was very useful.
I want to see the convection process where the temperature of food cools over time instead of the cylinder, what should I do?
You can follow the same procedure .
9:00 mesh method - triangles
solver setup - gravity check, -vector Y direction
Ansys-Tutor, will this procedure be effective if PCM is desired to be modeled/simulated? If so, what kind of Pressure-Velocity Coupling Scheme should be implemented? (In case the PCM is inside a 2D room fitted with a windcatcher). By any chance, Do you have any resource so I can check the setting up of PCM in Ansys Fluent?
Thanks!!!!
PCM analysis cant be done like this , as the density variation modeling is different in both of the case , we have a tutorial on PCM analysis , it might help you here is the link :th-cam.com/video/4qTnt0B3dOY/w-d-xo.html
Hi. thanks alot for the tutorials. I did this simulation and everything turns out great, but i had one problem, the cylinder's color in the animation gets black after a while and I don't know the reason. all the results sounds rational and there is nothing wrong, but the animation is not what i want, do you know the reason?
Check the colour map settings
may i know does the re-mashing and sizing these 2D is same as in 3D for the step ? and we are subtracting the circle from rectangular ,not rectangular from circle right ?
No the meshing would be a different one in case of 3D model.
We substract the circle from the rectangle. Rectangle is the body and circle is the tool body, in this boolean operation.
@@AnsysTutor thanks for clarification
Thanks for your video. I have a problem. If the surrounding air temperature is not 300K, for example 400K, how can I assign it ? Thanks for your help
you can do standard initialization with the tempr or you can patch the air domain with 400K tempr.
hi, nice tutorial.. i have a question.. where I can find the video of solutions ? (temperature, velocity..)
I know how to set up transient solution in CFX, now i tried in fluent.. calculation is complete but i cannot find the video
thx !
in cfx just press the timestep animation and save the video of animation
you can set the contour and animation parameters before starting the solution, after the solution get completed, open the solution animation play back and select the video format "mpeg"then click on write. then the video file will be saved in that workbench file directory fluennt folder.
@@AnsysTutor yy, thx so much. It was tricky for me.
Hi.. please make a video on blanching process of food.. in which food of any desired shape(slab, disc, cube etc.) is kept inside the hot water (say 80°C) for 6 minutes. Water is still in this case... How can I study the temperature distribution then..?
I have a question.......Why doesn't it allow me to select the "via simple coupling" option in the boundary conditions section?
Select the heat flux =0, instead of via system coupling
What is the "cylinder_wall_shadow" in the boundary conditions at time 15:16 and where did this get created. Thanks for your help.
If there is any fluid to solid interface there a shadow wall gets generated by solver.
Great video, though I didn't understand the need for setting the density of air as an incompresible ideal gas. Could you please further explain it?
The incompressible ideal gas model will vary the density of the air with respect to variations in temperature. Its similar to the bossenq model.
@@AnsysTutor ok, but what would happen if not changed to incompressible? Would we see the temperature increases without the fluid moving?
Yes.
@@AnsysTutor thank you very much
@@AnsysTutor is there a way to specifically select the bossenq model?
Hello, I tried to model same thing but with water as the fluid. However, my water doesn't flow and behave like a solid conduction (I used transient and didn't turn on the multiphase option). I changed the density type into boussinesq. Do you have any idea of why it would happen? Thank you!
There might be no connection between the cylinder and the fluid domain. Create the geometry carefully, taking different sketches for these two parts, then use the boolean tool as shown in this tutorial.
You must change density of water from constant to bossinesq. Fluid density must change with temperature to have natural convection.
Thanks alot! I really appreciate this video so much as I am just a beginner in Ansys and I am searching for sources to self learn. I am able to follow your steps. But I got the results with a lil bit difference .. may I ask is it normal ?
Yes, the result depends on the meshing. As your meshing might be different the result might vary.
@@AnsysTutor thank you for replying back. But What makes me confused is the dual setting. That wall(cylinder wall and thats shadow) have been already setted with 500K. And when turning on the b.c window of cylinder wall, there are no options(mixed and convection) in your video...
I don't know if you noticed, but when you applied the "via System Coupling" B.C., the message "not applicable, so skipping it." on the console appeared, so the B.C. that was actually used was "Heat Flux", which was per default set to zero. I think it is right either way because you are saying that there's no heat flux there, so it is insulated.
Yes you are right.
hi.. very helpful but i have question..i am doing same tutorial that you have been done in this video and i am following same procedures but when i want to select the option of via system coupling in boundary condition it is not visible its hide. even though i created two different surfaces
check if you have created the two surfaces in the same sketch or different sketch, generally you would get via system coupling if the wall is a external wall, for internal wall you will get the "coupled" , check if the wall you selected is internal one or external one.
@@AnsysTutor i checked again its different sketches . and for internal wall the coupled option is coming but the problem is that for external sides the option of via system coupling is hide. every step i have done properly and very carefully but the problem is same. guide me if possible.
same
Far as I know I did exactly what the video did but I do not get a result it is just blue every where. The scale indicates only 500K by the way. It seems that my Ansys has a problem with a fluid body and solid created from two or more sketches. This must have something to do with the bodies and/or interfaces not cooperation properly? Please Help anyone
Have you separated the both domain? ,check once by hiding any of the body.
why not use inflation_mesh_method in cylider_Wall?
i have followed the steps but i could not choose system coupeling ,it is greyed out for me,just like mapped interface
have you created the sketches in different sketch or in the same sketch. How many Surfaces generated in geometry.?
very helpful . thank you. i have a question . i m modelling a vertical solid cylinder in 3D , i have taken air as fluid domain and const wall temp to cylinder surface and remaining all the outer surface of fluid as pressure outlet . im not getting the temp plume exactly can u please help me.
what about the density of Air, is it Incompressible ideal gas model or Bousseniqs ?
its incompressible ideal gas .
@@saiganeshb3005 setting all boundaries to pressure outlet is causing the problem. For system to be properly defined, you need atleast one boundary as velocity BC. Make the bottom wall as specified velocity and put zero there.
How do I study 3d natural convection heat transfer?? a small brick room inside an air domain. Your help would be highly appreciated. I followed your tutorials. Great!!
you can do it similar to this manner, only change is the geometry . all the Boundary conditions and air density will be remain same, try it yourself, if you get any difficulties then feel free to ask.
@@AnsysTutor Thank you so much. Should I draw the plan?? I mean, the top view with the wall thickness or need to draw the whole geometry in 3D?? Since I am a very new user of the SpaceClaim, somehow I can't draw the room with the thickness. It becomes hollow every time. So no mesh inside the room to calculate.
My other quarry is if I use the steady-state simulation for getting the natural ventilation rate and transient simulation for the natural convection heat transfer, separately for the same room, will the result be okay?? Thanks in advance.
The geometry is not hollow., It might be transparent. Check that , if you do the meshing you could able to clear wheather its hollow or solid.
why did you make initialization "compute from" bottom wall? Why not all regions? Isn't the whole air internal region starting at 300K?
You can take any option of compute from that does not matter much.
@@AnsysTutor ok. Is there a way to select the bossenq model?
Hi thank you for this video
So how to chart temperature en fonction to time?
you need to go to outline view-> solution-> monitor-> report plot, here you can get ll the options to plot.
thanks dude for this perfect assignment.... I have a small query, how shall convey it you....
Yes please ask.
@@AnsysTutor thanks for reply...I followed your transient heat transfer assignment, still at the setup i couldn't get the 'Via system coupling' option as active. So provided ambient temperature to all four outside wall, but i m unable to get the simulation..... can you say what would have been the issue.....
Hello. When I try to write the animation file, it always says that the input file is too small and there was no video created. What could be the problem with this?
You need to first record the animation during the solution process.
@@AnsysTutor Hello. I had it set up just like in your video (thank you its very helpful) but when a I do Solution playback and write the file to save, there's an error message in the console read as "Input File Too Small". And the .mpeg file generated on my folder doesn't contain anything.
You need to save the video file after you finish the solution calculations. If you save the file and later open it you might not get the solution animation file.
@@AnsysTutor Hello. I followed this and it still gives me the same 'Input file too small' message in the console. I generated a .csx file, an the mpeg file and the .hsf files in my working drectory
Firstly i want to say thank you very much. But i have a question for you about my analysis. I want to analysis that plate by heated 70 C. I want to see cooling. But your analysis is different from mine. Your cylinder always at same temperature. How can i do cooling analysis with natural convection?
for this you need to patch the cylinder with the temperature, dont need to assign the BC on the surface.
Oww okay thanks a lot. Will i change other boundary conditions or just patching ? And i couldnt select biz coupling
@@AnsysTutor can you explain how to patch? And what to do differently if the cylinder started at 500K, but then it is allowed to cool?
@@AnsysTutor I hope you make tutorial of this too!
Thank you so much!! I click the button for subscribing. I ask a question. If I want to change convective heat transfer coefficient factor, how can I set this?? on the B.C? on the Cell zone?? On the material??
You can do this by selecting " mixed" or "convection" Boundary conditions on that wall.
@@AnsysTutor thank you for replying back. But what makes me confused is that there are no mixed and convection options in the cylinder sidewall window on the b.c setting step. I can only see the temperature/heat generation setting there.
Mixed or convection option only appears on external wall or the walls which is separate from the adjacent zone.
@@AnsysTutor I didn't know that. thank you for sharing. then.. If I want to add convection condition with other conditions(the cylinder wall temperature set 500 K, the surrounding air temperature set 300K) on this kind of cylinder convection problem, how can I set them on the ansys??
Thank you so much
Is it doable for a 3d steady state?
can you help, please?
Yes, it can be done in 3D also.
Why do you need to generate the solid zone? If your interest is in the fluid natural convection, the solid surface is irrelevant. Plus the animation starts with hot solid surface but cool core seems odd.
We are observing the temperature changes in the solid, without creating the soild zone it would be hard to know about the temperature changes upto the center of the solid.
Sir, I am doing same problem except that I am using heat generation source in cylinder domain instead of cylinder wall temperature. When I tried to plot Nu vs theta it's not working what may be the problem.I think it's because there is no connection between the cylinder wall and flow domain.if that's the problem how should I create a connection between them
How are you plotting the chart ,are you taking the polyline option or line as the location.
@@AnsysTutor polyline as location. Polyline is formed by boundary intersection.(flow_domain symmetry 1 and cylinder_wal)
what the use of using via coupling system which not been set any, it skipping.
"Via system Coupling " is used to define the wall as participating in the heat transfer calculations. its just like a information to the solver that this wall is made of conduction material & it can conduct heat which is to be generate from the simulations.
i followed you tutorial but i cant see the same animation what you did.
have you taken the air density as incompressible ideal gas or constant?
can you share the video so that I can try to figure out what is wrong. you can send me via telegram group, facebook or email. all the links are in the channel about section.
Hi, I followed your procedure but did not get the plume as in your video. The hot air keeps moving around the cylinder and does not rise up. I have chosen incompressible ideal gas
What is the time step have you choosen and no of time steps.
@@AnsysTutor time step is 0.1 and 600 time steps. But what I am getting is basically no motion of air, just local movement around that cylinder, It does not rise up as yours
The only difference is I did it in 2D and the cylinder was modeled as a hole in the fluid zone. I gave temperature BC to the hole boundary. Later I also tried pressure outlet at the top wall, but that causes air from outside to gush in
Add some thickness to the wall, the tempr might not be sufficient to heat the air .
@@AnsysTutor thickness as in making the fluid zone thick ?
sir, can you explain why we created new part from solid1 and solid 2
by doing so , we are preventing the solver to create contact region in between these parts. With the creation of contact region there would be additional time required for the solution in these contact region ,hence to save time it has been neglecred in the current analysis.
@@AnsysTutor thank you
Good day ... Pls can you guide me . I want to run analysis on steady state heat transfer but the values m getting is not corresponding to the journal I am reviewing ....
Can you do a video for it with the calculation of nusselt number
Can you share the journal file or the analysis on which you want the tutorial?
@@AnsysTutor okay. Thanks.. could you pls send me ur email.
Pls am waiting for your reply
As I said plz send the journal , to my mail id ansystutor7@gmail.com ,if it's possible will try to make a tutorial for you.
@@AnsysTutor okay tnx
i try to do this problem , but i cant select system cupling option it is inactive, i follow the step as per this tutorial what is the reson sir?
system coupling option appears for outer boundary region only . for all inner region "coupled " BC can be used for the same purpose.
@@AnsysTutor if i cant select the system coupling, then with what should i replace it? Or how to be able to select it?
I also cant set the cylinder wall with 500 K as well. Instead i only have cylinder wall contact region with 'interface' type. Can you tell me where did i do wrong, please?
you can use the "coupled" option to define the heat exchange between walls. Generally, System BCs are only for outer surfaces, that have only a cell zone on one side and an ambient atmosphere on the other.
check if you had created the geometries in different sketches or on the same sketch. Please follow the step as done in this tutorial, it would be better to keep a note of each step. so, while modeling, you will not skip any step and get the desired result as well.
@@AnsysTutor i got the same problem.system coupeling is greyed out
In boundry condition I can not find option via system coupling ( it is blurred) I have drawn sketch 1,2 surface 1,2 boolean, part
Have you selected the 2D analysis type before proceeding in workbench window.
@@AnsysTutor yes I did
Have you selected the energy equation.
Generally the " via system Coupling " is for outer boundary walls ,
@@AnsysTutor yes I did
DOES IT MATTER IF I CHOOSE INITIALIZATION AT ALL ZONE?
No, it can be initialize from any zone.
Thank you for your video....nice one......
you have set temperature as constant temperature BC......
How can I use temperature as Initial BC.....???
Use patching.
@@AnsysTutor Thanks....
For Same problem I used Turbulent Model but my results were totally opposite
Can you tell the reason ?
Have you changed the air density as incompressible ideal gas in material properties? What about the acceleration due to gravity value.
@@AnsysTutor yes everything is same as in video except instead of Laminar I used k-wSST Turbulence model, the solution is not diverging but the flow pattern is very different then in the video
Try once with the laminar model if there would be any changes. If not, then you need to refine the mesh.
@@AnsysTutor Results match with Laminar Model, hot air is escaping the hot surface And then recirculating in the domain same as in the simulation
So, what I will do now is to take your suggestion of refined mesh
What is your input in fluid domain?
Water liquid
Ansys-Tutor 1 more question, why the initialization is from the bottom not from the heat source (circle one)?
Btw this is great tutorial with good and simple explanation 👍🏻
Show the methods section in the slover
Use coupled method.
This movie is great, but for future works, I am begging you, use different kind of music or no music at all. After ca. 10 minutes of watching this one I became sleepy as hell :)
Watch our recent tutorial videos, we had used voice narratio for the each process.
I have found most of the TH-camrs deaf and dumb...I don't know wt they r trying to show...if they will speak during they will get more likes and views...
Watch our latest videos , we are not deaf anymore🙂🙂🙂.