On the Characteristic Surface of a Steam Boiler : 1st Report, Effect of Air Leakage into the Combustion Chamber

Abstract

The efficiency characteristics of a steam boiler are explained by an efficiency-load-excess air factor surface. We have called this surface the characteristic surface of a boiler. And we are able to draw a maximum efficiency curve to each constant fuel consumption lines on the surface. By the figure of maximum efficiency curve projected on the efficiency-excess air factor plane, the characteristic surface can be classified into two types, which we call A-type and B-type. A-type shows an indispensable condition in boiler. A steam boiler will be A-type or B-type, depending on whether sufficient air which has nothing to do with combustion leaks into combustion chamber or not. By a A-type steam boiler the excess air factor for the condition of the highest boiler efficiency increases with the increase of fuel consumption, and by a B-type boiler, on the contrary, the excess air factor decreases with the increase of fuel consumption.