Abstract
It is very important to achieve the low emission of internal combustion engines, it is well known that the lean combustion is very useful method to reduce the emission by control of flame temperature. In this study, experiments have been carried out to examine the influence of swirl flow on combustion characteristics for extremely lean premixed propane-air mixtures in combustion tube. The main conclusions are as follows. 1) The combustion improvement of lean premixed flame is very effective by using swirl flow. 2) The flame propagation speed (average and maximum) increases with increasing the blade area ratio at lean equivalence ratio. 3) The flame speed before through the blade in a tube increases with increasing the blade area ratio.
