University Third Year Project 1

[cma01]

Hi guys, I'm new to this forum. I'm currently doing Aerospace Engineering and I need some of your help. My project is a design of ultra high speed fan for domestic use. My supervisor expertise field is in electric motor and electrical circuit. So my problem is he can't really support me in the fan design process. I have few question,
1_Can I run a 3D simulation of rotating object in Comsol?
2_Should I use Ansys instead?
3_Do you have any text/research suggestion for the theoretical part?

There is another project about electric motor (in which my supervisor can probably help), I will have to learn the basic for electricity but If it is a better option I will put my full effort.

 

[BEMPE16524]

 

[MintJulep]

My project is a design of ultra high speed fan for domestic use.

1. Why did you choose this project?
2. What problem does a high speed domestic fan solve?
3. You're studying aerospace engineering, why not a more directly relevant project?
4. Are you free to choose your own project topic, or is there a list that you must select from?
5. If your supervisor (professor?) can't support you, who can?

To directly address your questions:

1. Yes, as shown in the video posted by Bempe.
2. Are you skilled with Ansys? More so than Comsol?
3. Sorry, I don't.

What would you simulate? Strength? Flow? Noise? Power?

Here's what you'll learn from simulations:

1. An "ultra high speed" fan will have "ultra high stress". Making it strong enough will mess up the aerodynamics.
2. An "ultra high speed" fan will be "ultra noisy". Noise is roughly proportional to velocity^3
3. You'll use more power for the same flow.
4. It will have undesirable failure modes.

 

[cma01]

1. Why did you choose this project?
2. What problem does a high speed domestic fan solve?
3. You're studying aerospace engineering, why not a more directly relevant project?
4. Are you free to choose your own project topic, or is there a list that you must select from?
5. If your supervisor (professor?) can't support you, who can?

1_ I didn't choose the project and the supervisor, they have assigned to me.
2_My supervisor only told me we need a fan for domestic appliance, and my supervisor has already a motor.
3_If I had the chance, I would have done propulsion.
4_There where only 2 project that he suggested me, one was circuit simulation and the other one what I'm currently doing.
5_That's the interesting part, when I told them about this problem the coordinator said you can ask for help to other professors, but now nobody is willing to help as they are full with students.

I asked different Prof. and they don't use COMSOL for 3D simulation for moving object. They use Ansys that I just downloaded yesterday. I'm learning it now, it will take time and I could get more help (for my first report I have 1 month).

I know my situation is not great, I've lost time learning Comsol and deciding my project with my supervisor. I literally don't know what to do, changing the project to anything electrical so my supervisor can help me and at least I wouldn't end up on my own. My current level in electrical stuff would be very basic especially in magnetic field.

 

[Lacquit]

1_ I didn't choose the project and the supervisor, they have assigned to me.
2_My supervisor only told me we need a fan for domestic appliance, and my supervisor has already a motor.
3_If I had the chance, I would have done propulsion.
4_There where only 2 project that he suggested me, one was circuit simulation and the other one what I'm currently doing.
5_That's the interesting part, when I told them about this problem the coordinator said you can ask for help to other professors, but now nobody is willing to help as they are full with students.

I asked different Prof. and they don't use COMSOL for 3D simulation for moving object. They use Ansys that I just downloaded yesterday. I'm learning it now, it will take time and I could get more help (for my first report I have 1 month).

I know my situation is not great, I've lost time learning Comsol and deciding my project with my supervisor. I literally don't know what to do, changing the project to anything electrical so my supervisor can help me and at least I wouldn't end up on my own. I read through a bunch of free publications https://edubirdie.com/examples/ to pick up possible work topics. My current level in electrical stuff would be very basic especially in magnetic field.

I think Ansys is hard to start with, so it might be a good idea to look for someone outside the university to prepare you.

 

[rb1957]

You've sunk time into Comsol, I wouldn't waste it by switching to ANsys. Maybe it doesn't do a good job modelling the flow, maybe it does ... either way something is learnt.

You should have a better understanding of what this fan is doing (beyond "my supervisor selected it for me"). Are you following on from some previous thesis project ? Your supervisor may get frustrated if you keep asking "why?" but you must, Must, understand what it is doing, and why it was selected, before you can make any sensible Engineering decisions. Maybe it is noisy, but maybe noise isn't any issue or understood and mitigated; or maybe overlooked and a problem. You need to understand what the fan is expected to do, how else to understand if your project has worked ? You need now to think of what you can measure to validate the model.

GL

 

[cma01]

You've sunk time into Comsol, I wouldn't waste it by switching to ANsys. Maybe it doesn't do a good job modelling the flow, maybe it does ... either way something is learnt.

You should have a better understanding of what this fan is doing (beyond "my supervisor selected it for me"). Are you following on from some previous thesis project ? Your supervisor may get frustrated if you keep asking "why?" but you must, Must, understand what it is doing, and why it was selected, before you can make any sensible Engineering decisions. Maybe it is noisy, but maybe noise isn't any issue or understood and mitigated; or maybe overlooked and a problem. You need to understand what the fan is expected to do, how else to understand if your project has worked ? You need now to think of what you can measure to validate the model.

GL

Thanks for your suggestion. I’m already on second semester and I dropped that fan project bc my supervisor couldn’t help me. So I picked up one of his project an electric generator for aircraft. He gave me a model and I’ve learned how to use ANSYS Electronic ( not fully but the main parts to collect data and result ). Even thought I don’t have the basis of electric motor I’m doing my best to understand the parameters that effects the motor performance. Now I need to focus on writing.

 

[Compositepro]

Key to designing a fan is to know what it will be used for. What flow vs pressure?

 

[rb1957]

hopefully your supervisor isn't "part management" ... "look, I have a fan, and I want to use it to blow air (on this thing). How hard can that be ?"

 

[3DDave]

For a school project the results should not matter as much as the approach.

I have professionally experienced far more stupid and badly formulated requests than this.

As Edison is supposed to have said (paraphrased) "I didn't fail in the trials, I was successful in finding 5,000 ways not to make a light bulb."

Professionally, one would be better off finding a company that makes fans and asking their tech support guys what they need to tell you the best match and, for extra points, have then tell what goes into that decision. Their best match might not be the right answer.

Were I to fault the OP I would start with "What the heck is an ultra high speed for a fan?" Are we talking shockwave formation at the tips of a 1 inch diameter fan? If there is a quantity, mention it. Then I would suggest that if such an item isn't commonly available as they hope to design there is likely not much information as why bother working on an item that doesn't sell? From there, make a comparison of fans along the spectrum of performance and see what it is about the fan blades that changes as the designs get closer to the goal.

Like, wheat used to be a few tiny seeds and farmers kept on selecting the ones that had more and larger seeds. Since planting and growing fan blades is not an option, one may look at existing work. Which designs are influenced by being really cheap and which are tweaked for performance. Try getting some that look promising and testing them in a quantitative way both as designed and at the desired "ultra high speed," or as close as possible before the fan explodes (wear a full face shield and a leather welder's vest.)

 

[waross]

Why "Ultra" high speed.
What makes the speed "Ultra"?
This will have different meanings to different people.
It could range from; A little faster than normal" to "Rocket Science".
Design is often a compromise.
The design of a fan, maybe more so.
Personally I would only consider an "Ultra" high speed fan if I was forced to use an "Ultra" high speed motor, or if there were space requirements that could not be easily met by other solutions.
Not likely for domestic use.

 

[GregLocock]

Fan design is a pretty good fit for aerospace. Analysing a bad sounding design (which it is) is just as valuable educationally as analysing a sensible design, and of course you can run a comparison between the two, and identify why conventional wisdom is the right answer. You'll need to come up with some sort of customer satisfaction metric, which might include cost, durability, efficiency, size, noise and so on. That sort of tradeoff analysis is real engineering.

Another idea might be to use the high velocity jet of air to energise a surrounding slower jet of air, and perhaps you'll invent something newish, or at least made a bad design less worse. We use that principle to use 80- psi air to cool engines on dynos. They are called eductors.

 

[rb1957]

is the point of the project to learn CFD modelling ?

is the point to mount this fan in some manner ?

"Another idea might be to use the high velocity jet of air to energise a surrounding slower jet of air, and perhaps you'll invent something newish, or at least made a bad design less worse. We use that principle to use 80- psi air to cool engines on dynos. They are called eductors." also high by-pass engines (low speed flow inside the cowling, high speed flow through the core, with the fuel and flames and such). also fuel pumps.