Hi guys, I want to design a gas burner and combustion chamber. I use natural gas as fuel. I want to control air to fuel ration, so air flow has to control. I have an air compressor as air flow source. Clearly, it's needed a mixture tube before the combustion chamber. Now I have some questions. 1. What is adequate speed in mixture? Absolutely low air speed in mixture cause combustion in mixture tube and high air speed cause turning down the flame in the combustion chamber. 2. What is the standard ratio of combustion chamber diameter to mixture diameter? I know combustion happen in the combustion chamber instead of the mixture tube because of air speed in mixture and mixture diameter. Also, I know the combustion chamber diameter has to greater than the mixture tube diameter. But I don't know the minimum ratio of combustion chamber's diameter to mixture tube's diameter. 3. How can I predict and control of flue gases speed in the exhaust? Actually, I can measure air flow and speed in mixture input valve, also for fuel. But I think gas flow and speed in the exhaust is greater than a mixture because of combustion's heat and volume increasing.