Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : September 03, 2017 - September 06, 2017
In order to clarify the frequency response characteristics of a lean methane-air premixed flame to sinusoidal equivalence ratio oscillation, we developed a new burner with a wall-stagnating flow that allowed measurement of the flow field by using particle image velocimetry (PIV). To create fluctuations in the equivalence ratio only in the direction of flow without varying the velocity field, fuel and air flow rates were controlled by alternately vibrating two sets of speakers. Fluctuation frequency f ranged from 5 to 50 Hz. Following results were obtained: (1) The oscillation amplitude of flame position of dynamic flame took an approximately constant value at beginning with respect to the increase of f, and then decreased. (2) At f > 20 Hz, the oscillation amplitude of burning velocity of dynamic flame became greater than that of the static flame, over the same equivalence ratio fluctuation range. This means that when the flame moves against (along) the fuel flow, the mass flux at the flame front increases (decreases) as compared with that of the steady flame.
