Combustion noise: Effects of the shape and size of burner nozzle

Effects of the shape and size of burner nozzle on the combustion noise were studied experimentally by using rectangular, square and circular nozzles of different sizes. Depending on the nozzle shape and size, the acoustic power has maxima and minima in the range of equivalence ratios between 1·1 and 1·6. For fuel-lean flames, the nozzle shape has an appreciable effect on the acoustic field, whereas for fuel-rich flames it has little effect. The acoustic power is proportional to the (2·8–3·2)th and (3·3–3·7)th power of the mixture velocity for fuel-lean and fuel-rich flames, respectively. For circular nozzles, it is proportional to the (1·9–2·1)th power of the diameter.