衝撃波による着火実験
衝撃波によるメタンガス着火に関する研究 (第2報)
1985 年 101 巻 1164 号 p. 55-60
詳細
1985 年 101 巻 1164 号 p. 55-60
The pressure of shock wave measured and calculated from its velocity is able to be estimated as described in former report.
And also, temperature (T5) at the end of shock tube can be calculated using pressure ratio P21 in the following equation.
T21=T5/T1=[(2+α1) P21-1](α1-1+2P21)/(1+α1P21)(α1+1)
where P21=P2/P1, α1=(γ1+1)/(γ1-1) and P1, T1 areinitial pressure and temperature.
The studies described in this paper is the investigation of ignition of methane-air mixture by shock wave using the shock tube apparatus.
Reaction between methane and oxygen is considered to advance rapidly, when concentration of methyl group ([CH3]) exceeds a certain threshold value. The time elapsed before reaching to the threshold is called a delay time (γ) for ignition. And, in the experiment, practically ignition is recognized by ascending of pressure and flames sensed by a photo cell.
Experimental conditions that are set up are as follows;
(1)Velocity of shock waves: 2.3 Mach-3.1 Mach
(2) Concentration of CH4 in the air: 3.5-20%
(3)Ignition will be appeared only at the neighborhood of end of shock tube, wherethe shock waves are reflected back and turn their propagation direction.
Results obtained from the experiments are
(1) Ignitions of CH4-air mixture are sometimes yielded by shock waves
(2) When the gas mixture is ignited, the delay time from excitation to ignition is usually between 0.3 and 1.0 milli-seconds, and ignition temperature is assumed also 1, 100 and 2, 000K.
(3) I gnition will be produced by adiabatic compression of gas mixture.
