Abstract
An experiment was carried out to confirm the validity of time series evaluation of supersonic mixing conditions by using the catalytic reaction on a platinum wire. Gaseous hydrogen was injected parallel to a supersonic freestream (M1≈1.81) from a slit injector, located at a backward-facing step. The time series condition of supersonic mixing was evaluated using a W-type probe with a platinum wire and a reference (nickel) wire. The evaluation was done by simultaneously measuring each electric power supplied by each electric circuit keeping the temperature of the wire constant. Electric power supplied to the Pt wire depended on the catalytic heat release rate (giving hydrogen concentration) and flow convection. Meanwhile electric power supplied to the Ni wire depended on flow convection. The results show that the correlation coefficient between these electric powers increased as mixing developed. Investigations were also conducted for the cases of helium, air, and no secondary injectant to compare with the hydrogen-injectant case. The results indicate that this evaluation method can measure the time-series behavior of the air-hydrogen supersonic mixing layer or coherent motion of turbulence.
