I'll be honest. My designs will never have a need for such a program but I viewed your entire video just to hear your detailed explanation. You're a very educated individual and a definite gem to have in the community!
Love your videos! As a PhD student doing lots of CFD work, I'd caution that CFD is not that simple - a lot of concepts are needed to get accurate results. I've spent hundreds of hours learning these, and I still feel completely in the dark. At velocities this high, turbulence modeling will be crucially important, not to mention meshing - I've spent tens of hours designing the mesh for a lower-velocity flow than this. I hope the program automatically chose a turbulence model behind the scenes - and even if it did, turbulence modeling is far from one-size-fits-all. It probably chose k-epsilon, which is a weak, time-averaged model. A small tweak to setup can make large differences in results, so it's important to verify a CFD run against known results. Intuitively, a 5015 blower causing peak velocities of hundreds of meters per second seems unlikely. This could be from bad CFD, or it could be from the assumption that the blower is pushing its open air flow rate at these backpressures. If you multiply average inlet pressure (in Pa) by average inlet velocity (in m/s), you'll get power. I'd be willing to bet that exceeds the fan's electrical draw, which is physically impossible. All that to say - the average Joe will probably get cool looking results from this. For very low-velocity, simple flows, you might even get useful results. But for high-Reynolds number, turbulent flows like this, it takes a lot of knowledge to get good data.
I agree with you, this results are not trust worthy. It is highly unlikely to have inlet 7m/s and end up with supersonic flow. The usage of compressible flow solver in the first place is questionable. Having said that, I found it a very good tutorial for many people.
This is what you call colorful fluid dynamics :D thanks for the explanation! It's cool that this free tools exists I'm sure you could refine it but as always GIGO.
@@hk318i I thought the compressible solver to be pretty questionable too. It wouldn't be too hard of a calculation (if I could remember the formula) to find the choke pressure of a duct this size - I'm sure it's far in excess of what this fan can provide. IIRC, it took around 80psi to get an air compressor blower nozzle (so, a few mm in diameter) to choke. Of course, you can have compressible flow below M=1, but that would be an easy idiot check for the results.
It would be great to have an updated video for Simscale. Their UI has changed a bit, to a point that it takes a bit of guess work to get a CFD simulation running. I'm currently working on a new nozzle idea for the part cooling on the Ender 3 V2 Neo. The hardest part for me was figuring out how to get the internal flow volume "open inner region." This is now done in the built in CAD editor. You still need everything setup the same way. The new command is flow volume>internal. The options have changed order, so your first selection is the small inside edge for the seed. Then, select the outer faces for boundary faces. After letting the volume create, then you have to delete the solid bodies you brought in from your CAD software, so that only the flow volume remains. Last, export this into the simulation setup. Without exporting, the changes stay in the CAD environment, but are not applied to the model in the simulation setup. It will appear as a cope of the original geometry in the list of geometries. Then, select the newly created geometry, and start a new simulation. Everything else is about the same as in the video. Be sure to pay attention to what's pressure and what's velocity,
You should have used a proper turbulence model instead of laminar. The flow coming out of a fan (whether radial or axial) is highly turbulent, if you are simulating flow after an axial fan, I'd suggest k-epsilon RNG model with proper wall functions. If radial fan, k-epsilon Realizable or k-omega model could be suitable. Also, keep in mind that the rotational moment after the fan could have a very big impact on the flow downwards. (which means at least some kind of rotationary momentum should be added into your inlet boundary)
Well, what do you mean it is a turbulent model? Do you mean that appeared vortexes? The laminar flow can be justified if it fits the Reynolds number below 2100. As examples, the von Karman vortex can be solved using a laminar solver as well. I can assure you that you will get the vortexes and it does not need a turbulent model as long as Re is below 2100. However, as many people agreed the CFD simulations are not that simple. In addition, as you said the mesh has to be well chosen and made. Actually, the mesh is the state of the art itself in CFD. The CFD software lately becoming more and more user friendly, however, without the CFD engineering background in fluid mechanics can lead to wrong conclusions.
This really is pretty awesome! I didn't even realize there was free software out there like this! Looks like im gonna be busy for the next... Forever, lol! Thanks Micheal. Really appreciate the effort you put in to your videos and the emphasis you put on giving back to the community! it truly is amazing what we can do when we work together towards a greater good!
Hobby CFD: take some coloring pens and just draw your own stream lines ;) don’t forget wall treatment and boundary layer, turbulence close your eyes and continue drawing ;)
Great video as always. I've already run through a couple of simulations for fan ducts I've designed on my printers in the past. Really enlightening, and way easier than doing the smoke test I used to do when designing ducts. Your channel is always so informative and easy to follow along. Keep up the great work.
CFD is quite complex. there are many factors to be taken into account. but it may give somehow a good estimation of flow direction and speed. If you go deeply you will realize that there are so many maths involved and good understanding of advanced flow equations are needed to get good estimations. For anyone getting inside CFD try to read the basics at least to know what you are doing.
This is incredible! I was just thinking how handy it would be to have a basic, hobbyist cfd program. One thing you can do to make your sims run faster is to take advantage of symmetry. Basically, cut your models in half before exporting and then make sure the fluid doesn't exit through that face.
Thanks for making this video! I'm designing a smoke collector for a laser cutter - basically a part cooling fan in reverse. I figured I could find some people talking about using CFD for designing part cooling fan ducts, but I didn't expect it would be you! I realize the CFD will be optimistic at best, but it will still help point me in the right direction if I'm doing something obviously stupid.
Great video, younger student me would have for sure enjoyed to learn by using these tools. I bet they love these lessons you teach! But I am also amazed by the amount of people commenting about turbulence models etc. I think it is kinda besides the point of the video, which seems to be introducing a free tool that anyone can use for doing hobby projects (which by the way is amazing, free tools for cfd are quite rare). And to all these wikipedia warriors in the comments: To begin with, the K-Epsilon that everyone is yelling in the comments is not a good model especially for curved surfaces and high turbulence simulation... It's just very fast for finding basic flow patterns, but handles near wall badly and is overly diffusive... For the simulation shown in the video if you want to stick with RANS models, a SST K-omega would probably be the way to go, but would need a bit more understanding of the case before saying for sure. If the case is not a steady state (which I think it is not since the two flows are pointing at each-other), even SRS model could be considered instead, if it is important to correctly simulate the flow around the nozzle.
Another great vid. Thnx Michael. Would love to see a basic modeling video. Ive tried a few times to learn but ultimately get frustrated. The way u explain things i feel it could help a lot of people.
The compression flow is now part of the pro subscription, and not given for free. I've been struggling beyond that, because their interface has changed. Where you create the flow region, there's now a separate cad editor so the right click option isn't there. Then it doesn't seem to react the same way and give me a flow region like yours - mine seems to be "inside" the solid volume that I modelled in, and I can't fathom that out. I keep getting a message about it being an invalid set-up, but it isn't really telling me why.
Spot on man, thanks for the video. This is exactly what I needed since I am in the process of making new fan ducts for my setup and experiencing problems with airflow.
As I have made a (pretty simple) fan design for my printer, which I am currently using, but am having trouble with the cooling on the back side, this is definitely something I will look at! Thanks Michael.
Should these simulations include a flat surface directly under the nozzle, to simulate printing close to the bed or top layers, if you print things that are flat?
Fyi unless your air flow is above 0.5 Mach or so, compress-ability effects in air are pretty minor. Should save you some core hours by using an incompressable simulation instead.
@@hudsonr.218 Mach 0.5 or faster cooling air would help when pushing for extreme speeds. I.e. >400mm/s and >10,000mm/s^2. But most cooling fans don't have anywhere near the power to do that. And you won't like the noise either. (Would make a vacuum cleaner sound quiet...)
How I know you're an F1 fan. The team shirt, lol. Can't wait to start buying McLaren merchandise for Danny Ric next year wooooooo Papaya and Blue baybeee!
Good stuff. I wish more people would use this type of thing to design parts cooling ducts. I've downloaded some pretty dodgy designs for my ender 3 before settling on one that was actually properly CFD optimised and it makes a world of difference when you don't have crazy amounts of flow restriction going on.
That's fantastic, I am an avid F1 fan and am trying to design the Mercedes W08 aero package to fit onto a 3racing FGX. It's a lot more aesthetic than functional, but it will be interesting to see what parts look like when stuck in this kind of CFD software
Ahh You are a teacher now it makes sense why you’re so good at this! I’m sorry I had to takeoff my patrion for now times are tough at the moment But I will be back once things get back to normal
The fan duct on my Reliabuild3D printer was designed by an engineer who works with fluid flow all the time at Flowserve. It is simple without any crazy bends (thing:3056162 on Thingiverse). It makes it look strange because the fan is hanging way out in the front. You want to get the air in and out quick. The 2 sided or all around airflow can slow down the incoming air from the other side.
Hi Michael, thanks for a very clear explanation. I’m inspired to model my Pajero tow vehicle attached to my caravan in an effort to analyse the best angle of attack of my purchased wind deflector for best effect. Hoping to find best location and angle to give optimum downforce without too much drag. Thanks again, Pete
If you are getting the error "A setup with 2 regions is being used in a single-region analysis type" -- you must delete all solids except for the new volume that you created like another commenter posted. It's not obvious from the error what step is missing, but that's it. TT does this and mentions it but it isn't explicitly shown on the video. Check out the video top right at 5:44 vs. 5:49 and you'll notice that all geometry except the new volume is deleted. If you're having this problem, go into CAD editor, look at the geometry, and remove (delete solid) everything except for the volume that you created. It's similar to a 'burn out' in the lost-PLA casting; the original solids must be removed. Then things should work. Also, in the new UI, you'll want to perform an internal flow-- but most everything else still works. The other difference with the new UI is that the gauge pressure is used and not absolute static pressure. I believe the new default values of "0" should be fine. Also, incompressible flow is free but compressible is not. That should be fine -- air is roughly incompressible below 230MPH (mach 0.3).
If you are working with newer version of Simecale than the one in the video, Instead of Using Velocity outlet use pressure outlet the same way. If you dont it will show an error and you wont be able to generate the mesh nor the Simulation Run.
This is awesome! Thank you for putting this up... I've wanted a way to get familiar with CFD without a lot of software/programming learning along the way. This makes it SO much more accessible. Thank you! By the way, wouldn't an incompressible assumption be ok for such a low pressure simulation since the mach numbers involved are negligible? I guess I'll have to try one and compare results!
Months ago i jumped at the chance! It was from one of the High School Racer videos when you mentioned it. Thanks for the great walkthrough. I'd love if the F.E.A And Thermal Design components could be covered on the channel too.
What I find missing is what to actually learn from CFD or FEA. I mean you can plot stresses or airflows, but it's harder to actually inform your design. Much is obvious already before simulation.
New to your channel but I’ve enjoyed and learned a lot from your content I’ve seen so far. I’m looking to get into designing my own prints, but am a complete newbie. What would be a good way and program(s) to start with to get my feet wet? Or if there are specific videos you’ve already made on this, I’d love to watch them. Keep up the good work and thanks for making these videos!
Always enjoy your videos. Unfortunately SS no longer allows CFD for compressible flows simulation on the free version. Seems they must have noticed an uptick of people using it and decided to monetise it.
As another user said, it‘d be more useful to learn how the results actually inform my design. Simple visualization of the first iteration is nice to look at, but whether the airflow hits the nozzle or not is obvious in the most cases. But there‘s a whole process involved in optimizing airflow before the outlet. It would be nice to see how you go from a first design, to an optimized one in multiple iterations, with help of CFD.
I'm working on trying to see how air flows through a paint booth. Hopefully the way you set it up in the beginning will help me as I had no idea how to set up the internal volume and entry points
@@justincredible5406 haven't used it yet, but when looking for cfd's. openfoam came up as one that was integrated into freecad about a year ago i think in version 17. But seeing a few videos on it and the general reviews of openfoam make it seem good. Though does appear to have a higher learning curve.
Thank you for this video ! You give us some very good information ! I want to simulate the pressure under my resin 3D printer Saturn 2 plate. I found some mathematical model not easy to implement so it would be great to simulate it ! The idea is that the efforts under the plate of the printer are getting very very high values during the last part of the z moving down in the fluid because of resin viscosity. The software doesn't support fine tuning of the velocities bur with the amazing UVTools it is possible to add temporisations for the first layers. So what do you think about using Simscale for my purpose ? Thanks again
Very thorough video! I’ve often wanted to check airflow on various parts cooling nozzle designs. Thanks for taking the time to demonstrate it. I was not familiar with this software. I’d be curious how similar or different the process would be using the Fusion 360 CFD module?
Thanks for making this, I tried this service several times and could never get it to work... just the trickiness of the UI methinks. This weekend I’ll give it another try following your guide
With the compressible simulation no longer being available, it should be noted that "incompressible" is the correct choice here anyway, because air is moving at slower speeds than mach 0.3. So, unless you got a really powerful fan...
Please get a compressor for your audio tracks and set an auto gain to common standard level. Constantly variations in volume on your vids. This one especially is too light in volume where one need to crank up the system and get blown away if app notification appears. Just a QA tip ;)
That's why Fusion 360 is great. You utilize the power of your PC but even if you toss it out a window, all the files are in cloud storage. Plus rendering and topology optimization tools use Autodesk's servers to do the math way faster than even a single monster PC could, but you have the option to run locally.
Fusion360 is web based on the local client application. It has cloud storage pretty much ONLY as an option. I have more power available to me locally than I'll get from some high latency Aws/Google/azure instance. It screams free, but sure third-parties can dip in and share your private designs. No thanks free is not equal to my data.
phew, really had me going there for a sec! i was just about to get "triggered" over the heresy of an assymetrical fan duct ... but then you've made the world good again!
freecad has openfoam, but finding good tutorials on that are hard. which sucks since it seems super interesting also like how it's free, open source, and your stuff is saved or exposed somewhere other than your own pc.
I am impressed!!! I have taken fluid dynamic classes and the programs we were told to use are not near as user friendly, at least not the way we were taught to use it. I will definitely be using this for my future designs. This is so cool and easy.
You'd be nearly right 😉 I "learned" CFD (read: how to click buttons in ANSYS) in undergrad, but I'm just now learning in my PhD how to use it to get non-garbage results.
That's a bit silly to do. Not many people will be able to use the full potential of a threadripper cpu and thus that's a waste of money. In this case, you're only using the resources when you need it. Also, I doubt any of the Ryzen solutions out there are powerful enough for CFD in a reasonable amount of time.
You might want to consider using Copper-filled Metal Composite HTPLA by proto pasta. I played around with it a little bit and the resistance level is nowhere near the resistance level that you showed for the carbon fiber. Might be something to play around with sometime when you have time I certainly don’t have the time right now to do something like that. You must send this after printing of course.
Well I´m not sure to know what the aim is here. Of course I can see the behavior of the air and in one case I can see there´s barely air the the endings but a simple fan duct should just blow in the right direction or not? I hope you can explain me which points are important? I´ve created a test STL with a box around it and it´s still calculating. I really would like to know more about what a critical position / area would be ... everything what would be red? ... or where I can see much less air at the end?
9:00 The fan characteristic you picked is not very representative of the actual flow anyways. The 'flow rate' fan manufacturers state is in open air, i.e. without any resistance. It is similar to how they state the static pressure, i.e. pressure with infinite resistance (blocked). In actual use cases, you are somewhat in between. In particular with fan ducts like this, you have a significant resistance, and thus cannot blindly take the volumetric flow in the datasheet. Instead, you will need to figure out the resistance, and use the fan manufacturer PQ curve to figure out where in the operating region you are at.
Any idea if this can simulate an air impulse? I've got some weird ideas for percussion instruments and I'm interested in testing the airflow inside the drum to see if any of my theories might work. 😄
Hi Michae , Have been trying to re-build my ender three with a SKR1.4 turbo board and a TFT 35c screen and 2209 stepper drivers.Following you guides and using your new editor choice(visual Studio) which I like . Iseem to load Marlin 2.0 into it fine then do all the changes OK but then when it comes time to compile there is no tick in the bottom tool bar ther are no mistakes and no problems but NO TICK TO PRESS TO COMPILE THE CHANGES .Lockdown frustrations here in Nowra and not knowing the software dosn't help,can you thanks Ian
What class did you teach and was it highschool or college? When i was working on my areospace engineering degree, i taught highschool myself:) its alot of fun
This is not related to the video subject but is a bigtreetech skr 1.4 be connected to a makerbase mks tft35 v.1. The display has an 8pt chord but the skr board has a 10pt input. They both have an identical display tft35 yet the connection is different. Is there a way to modify a chord/chords to connect them to each other. I also have a 10pin USB programmer if that can somehow help. I would be beyond grateful to get some help on this frigging thing. Its pretty much the bane of my existence right now and there's nothing anywhere about this which I'm very surprised by. But you're pretty much the man when it comes to this stuff so figured I'd ask. Thx
OK it's probably only me - but I have designed everything in Fusion360, exported it as .step; and it complains about "Sheet bodies detected. The model contains sheet bodies (surface data) only. The meshing algorithm requires at least one solid region. Try to solidify all surface parts." - any idea how to solve/fix this?
I tried to run the simulation on my own (slightly more complicated) design and found that *Open inner region* is not that straight forward when the geometry is non-trivial and there is no message that would tell _why_ this wouldn't work. The Start button merely blinks but doesn't do anything.
