Abstract
As part of the program of research for Bituminous Coal Research, Inc., means by which the performance of coal-fired steam locomotives can be improved are being investigated. Because of the importance of the method and of the rate of supply of air in any combustion process, an analysis has been made of the factors that govern the supply of air to the locomotive by its unique method of discharge of the exhaust steam to the stack through the front-end nozzle. The analysis shows that for any given front-end arrangement and locomotive, there is a definite upper limit of output of the locomotive at which the weight of air supplied will equal that required for the fuel burned. A similar but lower limit applies on the basis of fuel fired. Below these limits the percentage of excess air will increase with decreasing output of the locomotive; above the limits there will be a deficiency of air. The position of the limits is determined by the performance characteristics of the engine, of the boiler, and of the front-end arrangement. A program of research is outlined which is aimed to supply information (a) on the design of front ends for maximum combustion efficiency through proper excess air and minimum carry-over of cinders, and for maximum power output through reduction in back pressure on the cylinders, and (b) on the merits of overfire air in improving combustion efficiency through reduction in carry-over of cinders.
