Critical Dimensions For Mixing Venturi?

Hello. Does anyone know what parts of a gas inspirator (venturi) primarily affect the fuel/air ratio? I've tried searching high and low for the answer to this and can't find it anywhere. It seems like a black art or something.

See, what I'm doing is building a reproduction of a pest scaring device which makes a loud noise to scare away birds and animals from crops, just in case anyone was curious. The goal is to have an adjustable fuel/air ratio to vary the flame speed. This changes the "tone" that is produced. Maximum flame speed occurs when the mixture is stoichiometric and tapers off on either side. I figured someone on here would know about this because sometimes glass blowers make their own custom burners.

Thank you, Robert

Reply to
The Lightning Stalker
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The bible is the North American Combustion Handbook, which can be found on Amazon at

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might be worth the investment of $14.95.

Reply to
Terry Harper

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> It might be worth the investment of $14.95.> --

Reply to
The Lightning Stalker

I think you will find it is a black art. I am not sure the Combustion Handbook is going to help as it deals more with the rules of making a boiler safe rather than the exact proportions of a venturi.. There are only three things that can be varied once the venturi is built and being used, 1. the location of the gas orifice with respect to the throat (in and out) 2. the position of the choke and thus the volume of air available to be dragged by the gas flow 3. the pressure of the gas at the orifice, thus the pressure drop, thus the flow and velocity of the gas since the first involves usually loosening a nut and turning the threaded pipe, second involves loosening a screw and sliding the sleeve or disk choke and the third involves opening and closing a needle valve, normally the only one adjusted by the user is the third one.

Reply to
Mike Firth

Thanks for the info Terry, although I don't like purchasing books sight unseen from your recommendation and the review I purchased one so hopefully it will prove a useful reference. Arrival 2 -3 weeks IIRC what with Christmas and US to UK. Also with the dollar near 2 USD to 1UKP its only about £10 so not that much to pay, i've spent far more on books that I have browsed and assessed to be worth the money.

Reply to
David Billington

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