Will a helical surface improve airflow?
Will a helical surface improve airflow?
(OP)
I am sorry if this is the wrong forum but i did not want to put this in the mechanical forum because this has to do with wind speed and displacement and not so much the mechanical aspect of the part.
I am designing a throttle body spacer for a 4 cylinder engine. This part is 1" thick aluminum and will be placed between the throttle body and plenum. The inside diameter of the spacer is 2.5"
Now, there is a lot of controversy regarding whether a helical surface would be better than a smooth polished surface. So my question is, will a helical surface create a fast flowing vortex as opposed to a smooth surface?
Or am i looking at a negligible difference and its not worth pursuing.
Here is an example of what i am looking to make.
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I am designing a throttle body spacer for a 4 cylinder engine. This part is 1" thick aluminum and will be placed between the throttle body and plenum. The inside diameter of the spacer is 2.5"
Now, there is a lot of controversy regarding whether a helical surface would be better than a smooth polished surface. So my question is, will a helical surface create a fast flowing vortex as opposed to a smooth surface?
Or am i looking at a negligible difference and its not worth pursuing.
Here is an example of what i am looking to make.
ht





RE: Will a helical surface improve airflow?
Think about the laws of conservation of energy.
There is a specific amount of energy available to draw air into the plenum. This energy can accelerate a given mass of air to a given velocity. If some of that energy is diverted to rotational velocity, it must come from reduced mass or reduced velocity of the air in the other plane.
A bigger cross section will allow a larger mass of air as it will require less acceleration as the airspeed will be lower
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RE: Will a helical surface improve airflow?
RE: Will a helical surface improve airflow?
In either case, I cannot see any benefit in your application--especially not for flow rate.
I think you may have been mislead by those commercials for a similar product that claims the air would actually flow faster. The example they present, with the 2-liter bottles (one filled with air, one water), however, is not an accurate model of what is happening in this case. In the bottle example there is 2-way flow where the displaced air in the second bottle (and the vacuum created in the top bottle by the exiting water) is trying to equalize and the air needs to backflow through the water to do so. In your case, short of the pressure wave caused by the intake valve closing, there is nothing that is trying fight its way back through the incoming air--and the vacuum is on the engine side of the throttle body, sucking the air in. Of course, maybe that's not where you got this idea--but I've heard it come up before.
In conclusion, like the other poster implied--spend the money on a bigger throttle body if you want to see better flow.
RE: Will a helical surface improve airflow?
Expanding from something I read in a recent post on the subject of swirl, to better disperse and atomise fuel air, do it in the cylinder with many small eddies so the fuel throws back and forward between them, not to an outside wall like the cylinder bore.
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Will a helical surface improve airflow?
RE: Will a helical surface improve airflow?
No.
RE: Will a helical surface improve airflow?
In fuel injection, the fuel is introduced near the valve at about the last part of the total tract and would see little effect by that point.
In fuel injection engines the inlet tract length between the throttle body and the inlet valve is usually quite a distance to use tuning resonances for enhanced low end torque from ram tuning effects the cylinder inherently can produce.
Trying to make it sweril and keeping it in that mode thruout all the turns and direction changes would be quite a trick, in addition.