Flame patterns and combustion efficiency of Tai-Chi swirl generator

In this investigation, the Tai-Chi swirl generator (TCSG) was utilized to modulate the flame behaviors behind a traditional nozzle. This novel TCSG nozzle significantly increases the combustion efficiency, saves the energy and reduces the carbon production. The axial momentum of the central fuel-jet is transformed to the radial momentum when the fuel jet passes through the TCSG and then the turbulence intensity is increased. The flame modes, flame height, temperature distribution, combustion efficiency and concentrations of exhausted gases were determined using the direct photography, thermal couple and gas-concentration analyzer. The experimental results indicate that the flame fields includes six flame modes - jet-flame, flickering-flame, recirculated-flame, lazy-eight flame, swirling-flame and lifted-flame modes. The normalized flame height of 4.38 behind the TCSG is approximately 56% lower than that of 10 behind the pure-jet nozzle. The total combustion efficiency behind the TCSG is 38% higher than that behind the pure-jet nozzle. The peak concentrations of exhausted nitric-oxide (61 ppm) and propane (0.4%) behind the TCSG are about 67% and 95% lower than those of 190 ppm and 8.7% behind the pure-jet nozzle. Namely, the higher turbulence intensity behind the TCSG results in a higher air/fuel ratio behind the TCSG; and therefore higher combustion efficiency is carried out.