Characteristics of Combustion and Heat Transfer of Excess Enthalpy Flames Stabilized in a Stagnation Flow. 1st Report. Comparison of Excess Enthalpy Flames with Ordinary Flames.

Abstract

In order to develop new types of domestic heaters and burners for effective use of thermal energy and low emission of pollutants, characteristics of excess enthalpy flames stabilized in an axisymmetric stagnation flow established in a heat-recirculating burner were compared with thouse of ordinary flames stabilized by a non-heat-recirculating burner. The excess enthalpy flames can be stabilized at a low equivalence ratio and even in the stagnation flow with high velocity compared with the ordinary flames. The values of heat flux transferred from the excess enthalpy flames are about 1.5∼1.8 times as much as those transferred from the ordinary flames at the same flow rate of fuel. The flow rate of fuel for the excess enthalpy flame is about 40% of that for the ordinary flame under the condition of the same value of heat flux transfered from both flames. Then, carbon dioxide emitted from the excess enthalpy flame seems to be decreased by about 60% of that emitted from the ordinary flame. Therefore, the excess enthalpy flames are suitable for effective use of the thermal energy and low emission of carbon dioxide compared with the ordinary flames.