In function of total emissivity ε of the furnace inner wall surface situated behind the flame and others characteristics, a general formula for the combustion flame total emissivity εf is deduced. Also a new determination method for ε, with development of necessary specific scientific fundaments, is established. This method functionally is founded on the adequate decrease of radiation flux received by considered wall surface, using a tubular cooled screen with a translation movement. As a particular case of εf determination resulted the Schmidt formula, but are clarified the conditions of an efficient precision utilization. By functionally particularization of ε determination method can result the classical laboratory method using the total radiation pyrometer.

Keywords: Flame total emissivity, Wall surface total emissivity, Research-testing, Experimental furnace.