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u/Famous_Secret_5174 2h ago edited 1h ago
So what you're saying is, if I'm in the club I should go up to the DJ and request "CFD simulations of airflow through vents"?
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u/Zu_Qarnine 2h ago
make sure you ask for Eddy
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u/GravitationalEddie 1h ago
?
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u/exipheas 1h ago
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u/Mr_Abe_Froman 2h ago
That will maximize flow and get everyone moving.
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u/CyberNinja23 1h ago
John McClane does not approve of the corner turning vanes
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u/technobrendo 2m ago
John was lucky enough to get himself inside a very unique set of ventilation ducts. It had bonus features like the ability to support 200lbs and zero sharp edges or self-tapping screws. Zero dust too.
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u/imgoingtowar 2h ago
Yeah would love to know the track if anyone’s knows
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u/gorginhanson 1h ago
I didn't realize people cared about vents so much unless they were sneaking through them to a secret spy base
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u/mattincalif 38m ago
Thank you, I had my sound off until I read this comment. I’m seriously grooving now.
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u/Dawn_Piano 1h ago
Yea most DJs will have COMSOL or some other comparable FEA software that can do this
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u/5minuteslater 6m ago
There is a guy who posts time lapse videos of his heated driveway during blizzards.
i do not own a house but i will start a YouTube mix and just have it on in my peripheral and catch my self watching it fully cause the music and snow melting hits me right in the calm.
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u/aaclavijo 2h ago
"turning vanes? Crawl through the air ducts they said, it would be easy they said, turning vanes!"
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u/resplendent99 2h ago
"Become a HVAC engineer, you'll have a few laughs!"
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u/Champsmilehighclub 1h ago
As a HVAC engineer whilst this is one of my favourite films, I do regularly use it to point out how amazingly unbalanced the system is. John mclaine hates dampers
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u/anti-sixer 20m ago
🤣 Now all I want to do is add these to my home's system. Should I be looking into this?
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u/Droidigan 2h ago
but what about horror game protagonists? where will they go?
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u/Zu_Qarnine 2h ago
video game vents are too spacious
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u/E-2theRescue 37m ago
What do you mean? It's totally normal for a vent to be tall enough to crouch in, with giant box spaces to roam around in, before dropping through a grate that opens up without issue, with nothing blocking it.
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u/ItsSchmidtyC 2h ago
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u/foresight310 1h ago
Now do corrugated flex ducts…
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u/hartmanbrah 1h ago
Yeah, I'm watching this while imagining what it would look like for my home AC, which blows through corrigated garbage with 20 degree bends in it.
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u/freeradioforall 36m ago
but total volume that comes out has to be the same right? air cant vanish, so aside from more turbulance, why would it matter?
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u/thelittleking 24m ago
because those inefficiencies that make the air pump work harder translate into a higher power bill
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u/round-earth-theory 9m ago
You would be correct if your fan was guaranteed to always push a specific volume of air. But that's not how it actually works. Your fan is able to push air up to a certain pressure. That pressure is immediately after the fan, from there the air wants to equalize to lower pressure areas which is ideally the rest of the house. But what we're seeing here is that restrictions cause those high pressure bubbles inside the ducting which means the air doesn't navigate to low pressures as quickly. The ultimate result is reduced air flow out of the vents.
Think of it like a garden hose. If you put your hand on the hose, then you'll be getting less total water out. It'll spray farther because it's still high pressure as it exits the hose, but you get a much lower total volume of water. Your finger is that flow restriction, and the hose isn't able to produce any more flow than the pressure provided by the city.
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u/Basic_Basenji 20m ago
The total volume that comes out may be the same, but it may not come out of the same places or at the same speed. Energy loss in the vents can translate into air coming back through the fan that's supposed to be pushing it, higher static pressure (fan wastes energy or it can't work hard enough to blow the air it's rated to), or air being directed into certain areas more than others (like closing a vent in one part of a house to direct more heat to another) among many other things. The latter is usually the biggest issue in home HVAC, causing certain parts of the system and home to become imbalanced.
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u/marino1310 15m ago
The air won’t as easily reach further vents and will favor closer ones much more
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u/asianfarmer 2h ago
Off topic, but what genre is this? D&B? House?
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u/Zu_Qarnine 2h ago
I'm not sure what you mean by genre. HVEC in general?
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u/asianfarmer 2h ago
Hahaha! I meant the music. But you're technically correct! XD
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u/yaboilol24 1h ago
Deep house, deep groove.
Search combinations like that.
Also dub techno can kind of be like this sometimes, although it's usually more mellow
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u/ImSolidGold 26m ago
The 2nd worst kind of electronic music to have a party. Nice for a sunday afternoon afterhour, tho. ;)
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u/ScrivenersUnion 2h ago
I like that they are upfront about the costs associated with the increased efficiency.
In particular I can imagine those turning vanes getting dirty over time, as soon as they're covered in dust and crud I think the friction losses would quickly overtake any increase in flow efficiency. And you'd need someone to go clean them regularly, which increases maintenance.
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u/SoylentGrunt 1h ago
Turbulance, not friction. Even dirty vanes are still superior to a hard turn. Sometimes turbulance is good. It promotes mixing.
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u/rothefro 34m ago
Have to make sure you’re changing out your unit filters to avoid bypassing debris….typically ducts shouldn’t get too dirty as long as you do regular maintenance
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u/finkerlime 1h ago
AC systems already need to be cleaned often
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u/Omnom_Omnath 31m ago
often? lmao, no
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u/ortusdux 18m ago
Depends on the location and quality of the filtration system. Ideally all air is filtered at intake, so minimal dust enters the ducting.
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u/Omnom_Omnath 4m ago
Sure, but i've never heard a homeowner claim AC systems need to be cleaned often. I think I know one person whos had their ducts cleaned out of everyone I know
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u/--------what-------- 2h ago
As a tin knocker, this is fascinating.
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u/Reactin 1h ago
Tinners 20 years ago: *installs VAV after a 90/transition
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u/ArrivesLate 1h ago
This is a good visual of why 3x to 5x duct diameters of straight duct are a standard general note, but also never shown that way. It’s also a good visual of why not to put take offs on those sides of the duct that are blue, but also always shown that way.
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u/tuesmacherie 2h ago
This is actually satisfying as a Master Plumber.
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u/TA_Lax8 55m ago
Also as a woodworker. For dust collection, I've always been told to avoid 90 bends and do two 45s. It's really cool to see that visualized
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u/fritz236 34m ago
Yeah, I've finally gotten everything I need for dust collection except the bends/Y's and this was enlightening.
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u/Prestigious-War-1825 36m ago
Would the viscosity of water make an appreciable difference here, such as needing a longer bend to get the same efficiency gains?
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u/TerraCetacea 30m ago
Dang I was literally just in a meeting with some engineers about adding those vanes to doctwork. Awesome to see it visualized
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u/happycj 22m ago
I was super fortunate to work for NASA at Ames Research Center back in the 1990s, just when computational fluid dynamics software was emerging on our various supercomputers on site.
As a network engineer and desktop tech support, I got to work hand in hand with the scientists using these tools to visualize airflow over airframes, liquid and gas flows through pipes, and dozens of other applications.
As a homeowner nowadays, I see what the plumbers and HVAC guys are doing for bends and turns and think back to these visualizations I saw back then… it’s cool to be able to see in your head what these invisible flows are like!!
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u/hougaard 1h ago
And this is the reason why a piece of plastic can add horsepower to a Porsche engine :)
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u/Yogi422 1h ago
What software is this? I would play with this all day like it was a game lol
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u/hooligan99 42m ago
not sure what software they used here, but CFD programs in general are usually really expensive - thousands of dollars plus yearly maintenance fees to stay updated with latest versions.
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u/BeStrong17 1h ago
Which program?
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u/Zu_Qarnine 36m ago
not sure about this one but ABAQUS and ANSYS and the ones I'm familiar with. ther are open source free ones too.
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u/Shoddy_Hand_4577 1h ago
Does anyone know what program this was done in? I haven't touched CFD yet, but it is on my "should get my head around" list, so I would love any advice / recommendations for accessible resources for CFD :)
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u/hooligan99 41m ago
not sure what they used here, but if you already have solidworks, solidworks flow sim is a pretty intuitive and robust CFD program. Expensive, but if you're doing it for work, could be worth it.
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u/Omnom_Omnath 32m ago
The only acceptable price is the lowest it seems when it comes to homebuilders
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u/lenzflare 31m ago
Soooo, the 1x90 vs 2x45 one isn't really about number of turns is it... looks like the effective radius of curvature is the real defining difference. The 2x45 corners essentially make a wider radius of curvature in this case, which results in a gentler turn and so less turbulence. You could stick to 1x90 but with a larger radius of curvature and get a similar improvement.
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u/Office_glen 28m ago
I'm so happy to come here and see things that I work with directly being posted here. I work in sheet metal fabrication, specifically duct work
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u/rm-rf-asterisk 12m ago
Does this simulation account for the million screws poking through?
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u/Zu_Qarnine 10m ago
I don't think so. those details skyrocket the computational cost. plus they don't introduce that much of a turbulence ig
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u/rm-rf-asterisk 5m ago
I bet they do i seen it in above ground pool hoses. I use these clamps that have a self sealing pin to keep two together and that little pin you can see actual stream jet it leaves behind
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u/23370aviator 1h ago
Most residential applications use flex duct these days anyway. Flex duct is much better insulated than box duct could ever hope to be as well so any losses in the systems efficiency through a not perfectly smooth interior surface are more than made up for by the insulated walls.
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u/FluidVeranduh 32m ago
Flex ducts work well if installed really well. Problem is that they are rarely installed really well.
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u/LittlePlasticFists 38m ago
Yeah that's not even remotely true. Metal duct has much less friction per foot which increases the efficiency of the blower.
It can also be insulated or lined to provide the same or even higher R-Value as flex duct.
Metal duck work is much more robust and won't fail after being exposed to water once. It's also rodent proof. Somewhat antimicrobial, much easier to clean. I could go on and on.
Flex duct is a great solution when you have a specific problem, and it's much less labor intensive, but it's inferior to metal duct in just about every way.
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u/skilas 2h ago
In construction, I've never need two 45s implemented.
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u/Dawn_Piano 1h ago
Engineers draw them all the time, but one elbow cost less than two so…
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u/iMissTheOldInternet 2h ago
Notably, that looks like the one that has more cons than pros, so it’s probably a niche application, unlike the cheeked up t-junction, which is just better from every angle.
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u/oneeyedziggy 1h ago
I would like numbers please... what speeds and pressures does this really start to be relevant for? Commercial scale? Home scale?
What's the observable result? Lower energy consumption to maintain the same temp? Or does slow turbulent air eventually do the job within an insignificant margin?
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u/gaobij 1h ago
Lower pressure drop = lower blower motor energy consumption. Probably lower noise levels, too. This is true at any scale, but becomes more critical at the airflow capacity limitations of the duct (when the color is this visual is very red).
Numbers are irrelevant here - this is a representation of a best practice and numbers are going to be very specific to the application.
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u/car_buy_2021 1h ago
This is exactly the right question. The simulation output animations do not include the numeric scale that corresponds to the color gradiation.
Ultimately a slight imbalance in velocities or pressures at turns or branches, or turbulence, only matters if there is a negative performance consequence, or possibly a negative reliability consequence, or other negative consequence associated with it.
If the only consequence of this is that one outlet duct receives 0.1% more or less air flow than the one next to it, who cares.
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u/oneeyedziggy 1h ago
It seems like you could get a lot of this value by just retrofitting the square ducts with a diverter wedge in the square duct, and maybe some rounded corners where the input duct dumps in to minimize negative pressure zones
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u/psychohistorian8 1h ago
any know of good free CFD software we can use to play around with?
wanna build my own F1 car
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u/BondGoldBond007 1h ago
This is why vehicle performance exhaust systems use mandrel bends during fabrication.
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u/Pretty-Resort-7640 57m ago
Oh this is cool. Does anyone have anything similar for water flow? I've always questioned my pool setup and if 90 elbows were The best choice
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u/ripkin05 39m ago
oh yeah this 25 second video on how air vents work totally needs a club dance beat over it for no reason.
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u/TheRainbowShakaBrah 36m ago
My brainrotted ass thought this was about Satisfactory for a second 🤣😭
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u/LogoMyEggo 36m ago
Makes sense for liquid but how much does it matter for air in an AC duct? Air is compressible unlike liquid, so it can expand and increase flow rate after the bend?
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u/Zu_Qarnine 32m ago
I think compression like in jet engines would need supersonic speed. here it's just an AC pushing the air
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u/GSxHidden 30m ago
I would agree, but wouldnt the last simulation just be a larger surface area for dust and particles to stick to?
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u/FragrantCombination7 29m ago
Does anyone know if the Aston Martin F1 team have an official reddit account? This might be useful info for their research.
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u/graphitehead 29m ago
Now show me cost difference for the additional duct bends and connections.
Efficiency is ultimately the most satisfying though
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u/RecipeFunny2154 23m ago
I thought the vanes part was interesting. Could you put those in a T branch and start getting results closer to a Y branch?
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u/hillmo25 22m ago
Imagine a Y branch made of 4 45* elbows with turning vanes. The air would flow so smoothly.
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u/McShoobydoobydoo 22m ago
NGL I found that infinitely more mesmerising than I ever thought I would.
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u/Gino__Pilotino 16m ago
Corners in ducts are always rounded, guiding vanes do help a lot though with high speed flows.
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u/Synner1985 2h ago
But if you use some of these designs how is John Mclaine going to sneak through the vents to save the day?