ScienceAsia 30 (2004): 279-287 |doi: 10.2306/scienceasia1513-1874.2004.30.279

Effects of Air Preheating on Double-Swirling Stabilised Flames

Roongrueng Bhidayasiri^*

ABSTRACT: The use of air swirling with fuel to stabilise flames in industrial burners or in gas-turbine engines has become widely practiced, but limitations concerning the levels of intensities of swirlings remain a problem. Previously, it was observed that at highly intensive swirlings¹, double swirlings could create opposing movements which reduced the net momentum, and suppressed the intensity of swirlings. However, it could not explain the results of the reduction in intensities of swirlings. Therefore, in this investigation, the primary objectives are to establish such results, as well as to provide supports for the previous study. Experimental set-up was the same as before, except for the introduction of double swirlings in the environment of increased temperatures. The present study showed that air preheating produced results consistent with the experiments using ambient air temperature. Preheating had the effect of lowering the lean flammability limit, by 40% in some cases. The flame in its physical characteristics was smaller. The composition of blue flames increased. The concentration of carbon monoxide was reduced, for some instances by 50%.

Download PDF

Department of Mechanical Engineering, Faculty of Engineering, Mahidol University,
25/25 Bhudhamonthon 4 Rd, Salaya, Nakornpathom 73170, Thailand.

* Corresponding author, E-mail: Rep438@parliament.go.th

Received 28 Jan 2004, Accepted 26 Jul 2004