Experimental Investigation of Flame Stabilization and Heat- transfer Characteristics of Counter-flow Micro-Combustor

The local temperature measurement in a small channel is important for the evaluation of the performance of a micro-combustor. The channel size of a micro-combustor becomes small in comparison with the flushness length of a flame. In this paper, a temperature measurement technique for a small channel flow of high temperature is examined. Then the flame stability and a procedure to raise the enthalpy of a pre-mixed un-burned gas are examined using pass-through and counter-flow micro-combustors. A thin sheath thermocouple is introduced in this experiment. The temperature at the center of a small channel does not show a maximum temperature when the temperature is measured by a thin sheath thermocouple. Deviation may occur by due to the thermal conductivity of the sheath. Thus the sheath should be inserted deeply from the center of the channel. The circulation of a pre-mixed gas in a small combustion chamber is important for flame stability. The heat exchange through a thin partition wall between pre-mixed gas and exhaust gas contributes to flame stability. Iron and copper base plates for a micro-combustor are introduced to examine the increase in enthalpy of a combustion flame. The specific enthalpy increases as the pre-mixed gas flow rate increases. As a result, the heat exchange between the inlet and exhaust gas by a counter-flow micro-combustor brings about high enthalpy combustion and high thermal efficiency.