I 3D Printed an ELECTRIC MOTOR FAN

3D models

#3dprinting #fan #electronic

[MakersMuse]

That's a really neat and simple way of making a BLDC motor! I'll have to try it mmm

[JD-ldck]

I'm guessing it has to do with the diameter of the intakes of the EDF and the 3d printed ones. It's the biggest difference I can see and would guess it to be very influential on both the flow rate and the static pressure delivered by the fans. But I don't know for sure, am not an engineer in this regard. Just know that I hate tomatoes too.

[fluxcapacitor]

Hi Integza! Another cool projekt :) The close view of your impeller at 4:03 shows why… well, why it sucks at sucking anything ^^
It has the wrong, almost "reverse" geometry for such a tiny inlet (same for the second model at the end of the video). Moreover, one cannot simply "open the intake wider" as suggested elsewhere in the comments. Otherwise, the volume of the shroud would become so small that the blades would no longer compress the fluid. 
The solution here is to twist and orientate the blades the opposite way:
1. At first close to the the shaft (the "hub") your impeller needs an important geometrical part that is missing in your current models: the "inducer". The inducer is shaped and acts almost like a regular PC fan or propeller. Its blades are wide, with a high incidence angle (say, about 45°). Front facing without the shroud, they should look like almost those of a colored windmill toy. However in your current model, in this place your blades are shallow and oriented normally to the incoming flow, so they can barely pump anything. The inducer once there induces a high velocity to the fluid in order to suck it inside the engine (with not so much pressure on the other hand): that is to say, this missing part acts as a PUMP.
2. Then, as the blades of the inducer expand radially outward, thinner and thinner, they really become the impeller. They straighten up, and end up at their orientation at the periphery is almost radial and completely upright (i.e. the tip at the trailing edge should be normal to the shaft and to the external flow – the one outside of the engine) a bit like the blades of a water mill this time. In this second trailing part, the impeller acts this time as a COMPRESSOR i.e. better at creating pressure than accelerating the air (but it doesn't matter then, because the fluid velocity will be already high at this point, thanks to the inducer!).
So a centrifugal compressor impeller indeed acts as you explain at 4:38 except it imparts velocity to the fluid first, then compresses it, in this order :)

[CheeseVRC]

My guess would be that it has to do with turbulence caused by the impeller, use a smoke machine (or burn some tomatoes) to see how the air forms around both the EDM fan and your impeller fan. Also, since your impeller is more structure than fan, the output thrust should be less than the EDM fan. Which is more fan than structure.

[JadeEyedWolf]

I'm no engineer, but from just looking at how significant the difference is between intake diameters (EDF vs 3D print), my guess would be that you're restricting your flow rate on the 3D print. Might be able to compensate with higher RPM, but I bet that would more than likely exceed material capabilities; probably easier just to scale size, and maybe even reduce RPM?

[triplogabriele]

Integza make a Turbo rollerblade using its self-built engines

[McIverJohn]

I produced a similar shape of rotor to yours a while ago. It was part of a small 3D printed supercharger. The rotor is actually hybrid being half way between an axial and centrifugal compressor stage. I've since moved back to a 3 stage axial compressor which is a bit more predictable. In theory each axial stage should offer a 1.2 pressure rise while a centrifugal compressor will offer something around 3.0. You exist somewhere between these values. The tip clearance for the hybrid rotor may affect the performance.

[SillyNt]

Zepplins or Blimps using impellers or jets for directional force would be an awesome video!

With all of these balloons and such floating over us recently I'd love to see how you can make things nerdy and fun!

[eruiluvatar]

I believe that the thrust difference is down to mass flow, the EDF fan is optimized for flow rate while the Dyson impeller is optimized for pressure. It also seems to have much less blade area requiring higher RPM for the same mass flow.
A higher pressure will provide a higher thrust provided the same nozzle area but will also require more power to drive the fan and may or may not be realized depending on the rpm and the throat and nozzle shape.

[c.m.s]

What i can recall from fluid mechanics classes is that by compresing a fluid you decrease its speed, so the centrifugal fan that you designed basically outputs a slightly compressed air but at a lower speed, in jet engines this is desired because you need a high density of air with a low moving speed and by igniting fuel you generate thrust .

[TheTarrMan]

A) Your pump style is adding a compression stage which is a energy loss (and the entire structure is adding extra mass so now conservation of energy is involved).
B) A wing style fan works exactly like a wing, which would be playing around with pressure differentials basicly (very efficient).
C) What exactly are you trying to do here because there's a lot of engineering and considerations that goes into aerodynamics. What media are you trying to move because each media has its own most efficient blade profile and even the temperature can interfere. Fan blades for like a house fan use a general profile, while the blades manufactured for a jet would have much finer tolerances on their profile callouts on the blueprints. Surface finish callouts would even be a factor.
Idea : If you want to make a more efficient fan, make one where blade profile can change. Like maybe have an inner metal structure with a rubber bladder over it that's inflatable. Play around with the thickness of the rubber bladder to help control the profile. (Add some stiffer rubber patches or fiberglass or something so it doesn't just turn into a big balloon.) Then have all sorts of sensors that measure the atmospheric conditions with a computer to do all complicated calculations to determine the most efficient profile. Most of logic motors have speeds their most efficient at as well so thet can also be part of the calculations.

[Bnghwy]

Your channel is awesome I just signed up as a patron I'm 42 year old auto technician but I lost my legs and took 3 years to heal and 2 years to get up outta bed and I tried by starting to watch YouTube and this awesome stuff I've seen gave me motivation again maybe there still something I can do anyway thx being so cool

[ruedogs]

A centrifugal fan is more useful for static pressure into a chamber especially at those smaller sizes whereas the edf is more for linear air flow. The centrifugal fan will work better at higher rpm (dysons spin at a crazy speeds ) to create high static pressures but not huge flow

[marcelkanter]

Some thoughts:
- Keep in mind for your deign: Modern jet engines try do move the air as slow as possible through the engine, but a lot of them. The actual fan in an jet engine has low rpm when compared to the other rotating parts in it.
- Match the overall inlet area and the ratio of free area to closed area for comparison. (Comparing apples with bananas gives reasonable results only until a certain point)
- Change the angle of attack of the leading edge of our compressor blades (There is an impedance mismatch at the very first edge - You chop of the air at the inlet with you compressor blades and rely on centrifugal forces. The speed difference is too high. Better "cut" into the air at the first edge.) The higher the velocity difference the "flatter" the first edge should be. Have a look how the slowly rotating blades of a jet engine are shaped.
- change the angle of attack of you compressor blades with radius. At the axle it should look more like an I or L, at the outer radius more like an S. This depends on the type of "fan" you try to build. Radial or axial accelleration.
- use an stator with thinner blades (impedance mismatch)
- the stator should look more or less like an inversed version of your compressor. The air flow directly after the compressor is spiraling, this reduces thrust, because the side-wise portion does not contribute much to the trust.
- reduce the distance between your rotating parts and the inner side of the hull. For example: At the red lines in your design, there is air "leaking" over from one section to another section due to the rotation of the compressor. At the back side of the blade, vortices occur which break air flow and create friction.

[benjaminshields]

I was just recently working on an impeller design for a pressure based system and not flow. I also have a background working with a million different motors, including designing my own BLDC ESCs.

If you're using the same motor, make sure the controller you use is the same as well. Long story short, different timing and/or control will result in different outcomes.

Measure *everything* I'm sure for the sake of brevity, you've left out a lot of this. But, if you're going for the same type of performance, make sure your impellers, nozzles, intakes, chambers, etc. All have the same geometry. You want to get the curve right, the thickness right, the angles right, the sizes right, just about everything. Reduce the amount of leniency for "good enough"

Shoot for the smoothest and most consistent surface finish you can get on your printed parts.

You might gain some mileage by combining your best printed parts with the stock parts as well. A printed impeller with the Dyson chamber, for example, and vice versa. You then get a comparison of what is and isnt working from your design and you can isolate where the problem truly lies.

[GWRcustomweathering]

To my knowledge an EDF is biased to pushing a large mass of air at a high speed but at low pressure (this is comparable to horsepower). Whereas a ducted fan is biased to creating less airflow but much more pressure/higher PSI etc (this is comparable to torque). It's irritating when people make a motor jet engine on other youtube channels using an EDF and a combustion chamber, as they should be using a ducted fan instead or even better an electrically driven turbo charger impeller wheel (as these are compressors rather than just fans). Thank you for your videos. I feel they are actually getting even better.

[_iyalei]

Is it possible that your fan is stalling? The idea there is that the static pressure behind the impeller rises to a point of being higher than what the impeller can sustain. The way out there would be to try a different outlet/nozzle geometry, maybe with a larger aperture. Or to change the impeller geometry to maximize static pressure. That may be a good topic for a future video btw 😅

[martinblade]

Finally, something that it's perfect for the the theory I'm learning in flight lessons!

Fair warning, part of this is going to seem counterintuitive, because to move the most air possible with a propeller we actually reduce the angle of attack of the propeller so we can increase the speed of the propeller. We want the propeller to move as much air as possible in the least amount of time, cause the end of that runway is approaching pretty quick during takeoff.

We can either move a decent amount of air per rotation but rotate much slower (high propeller angle of attack), or move less air per rotation but rotate much faster (low propeller angle of attack). That last one gives us the most air moved per unit time, which is what we want during takeoff because we need to move as much air as possible as quickly as possible.

There are actually two types of propellers used in aviation, fixed pitch and variable pitch. Fixed pitch propellers are not able to have their Angle of Attack changed during flight, so we use a design that is a compromise between moving as much air as possible during takeoff and efficiently moving just enough air during cruise. Variable pitch propellers are able to change their Angle of Attack during flight, so we can get the best of both worlds. To get the best performance out of a propeller during takeoff, we have to move as much air as possible with the propeller. To do this we actually use a pretty shallow angle of attack, but as high an rpm as we can get out of the engine. We move less air per rotation of the propeller, but rotate much faster to more than make up the difference.

The exact numbers vary based on the plane engine and propeller, but these numbers are taken from the Pilots Operation Handbook for a Bonanza A36. Lowest officially recommended cruise setting is 2100 rpm during cruise vs 2700 rpm during takeoff. So a 28% increase in RPM during takeoff. Even with a small reduction in air moved per rotation, the increase in rotations per minute more than makes up for it.

By the way, I'd love it if you made some type of plane that might be used to test the idea of a gas turbine electrical generator making power for electric motors powering fans or propellers of some variety. I think that's probably where aviation will end up. Right now batteries just have too many weight problems and lack of range problems for practical, widespread use in aviation. Plus there are a lot of benefits from being able to reduce the overall weight of a plane during flight as well as changing the center of gravity while in flight. Changing the center of gravity alone can drastically increase the efficiency of aircraft because it lets us reduce induced drag from the elevators. Can't really change the center of gravity or total weight in flight with batteries, but we can with liquid fuels.

[travisdutton]

One thing you could do integza to not only demonstrate your hatred of tomatoes while also using your love of creating your own stuff with a 3d printer. Use tomatoes as a crash test dummy… create a high thrust engine and mount it on something that has low friction bearings. The tomato being the cushion so as not to damage anything around it. 👍🏻 you can even put this on trial and use numerous different engines to see which of your creations do more damage to the tomato

[intellectualbaguette]

The "and that's a very cute fan" bit genuinely brightened my day. Thank you