Comparison between Frequency Response of Pulsating Partially Premixed and Diffusion Flame

Abstract

The objective of the current research is investigation of the pulsating flow effect on the size of partially premixed and diffusion flame, experimentally. The pulsation provided through a rotary ball valve in accordance with a variable speed motor arrangement increased the flame temperature and thus more heat is released. The used S-type thermocouple can measure the flame temperature at strouhal number [St] is 0 and 0.005 for the flow, the flame temperature has been measured at five planes as each plane has five radii. Fast Fourier Transform (FFT) has been used to determine the dominant frequency response of the pulsating flame temperatures. Increasing strouhal number of the mixture (LPG fuel and air) flow increases the turbulence intensity and thus the dominant frequency response of the pulsating flame increases. The dominant frequency at St=0 is larger than the dominant frequency at St= 0.005 for all the planes of the combustion chamber. Increasing strouhal number reduces the size of the pulsating partially premixed and diffusion flame by a maximum of 40 and 35 %, respectively. The pulsation process will optimize design of the burners.