> I have heard from an informed source that ALL genesis engines had a tendency > to pulsate.
Bert, I was waiting for some results yesterday so I idly googled (and binged) "gas jet pulsing' which thrust me into the world of pulse jet engines. The first thing I noticed on Wikipedia was the phrase 'resonant combustion'. I've seen gas burners pulse, so I figured it was time to try that as a search. This popped up in a paper on noise from gas burners. "Combustion driven oscillations Combustion driven oscillations arise when positive coupling occurs between the flame and the acoustics of the combustion system, ie when the flame acts as an amplifier of disturbances (acoustic or fluidic) at some natural frequency of the combustion system. Although this phenomenon is relatively uncommon, when it occurs, it can give rise to extremely high noise levels within a relatively narrow frequency range. Hence the descriptions of this phenomenon as: - Combustion oscillations - Combustion resonance - Pulsations - Combustion hum Combustion oscillations normally occur if there is some similarity between a characteristic frequency of the flame (eg the mean residence time in the flame, or an eddy shedding frequency in the fuel or air supply to the flame) and a natural Helmholtz resonator or organ pipe frequency in the combustion chamber, flue ways, or air and fuel supply systems (often in combination)." http://www.handbook.ifrf.net/handbook/cf.html?id=176 (International Flame Research Foundation) I didn't buy Tom Burns' (excellent) theory, as pulsations are usually at a constant frequency. If you had bubbles or surging, it wouldn't be a fixed frequency. [Maybe it isn't anyway?] That last paragraph above should give you some ideas. Before you change the tank, try altering the gas pipe length and/or the flue size (insert a liner ?) Pete -------------- next part -------------- An HTML attachment was scrubbed... URL: http://postfix.45mm.com/pipermail/sslivesteam/attachments/20110719/d58dc641/attachment.html _______________________________________________ SSLiveSteam mailing list Send messages: SSLiveSteam@postfix.45mm.com Cancel subscription: http://postfix.45mm.com/mailman/listinfo/sslivesteam Rules: http://www.45mm.com/sslivesteam_guide.html
