Experimental study of the flame propagation of gaseous fuel based mixture using optical visualisation

Abstract

Abstract At this article presents experimental investigations carried out to determine the flame kernel propagation of gaseous fuel-air mixture under spark-ignition engine-like conditions. Various combustion processes taking place in an experimental combustion chamber are discussed. Consecutive shots of the development of the fuel flame front in a constant volume combustion chamber under different initial conditions are presented. Direct visual recording of an image of the combustion process is performed or Schlieren photography techniques are used. Modern types of spark plugs with different gaps in the entire price range are examined. CNG and LPG are used as gaseous fuels, since they are the main alternative fuels used in internal combustion engines for vehicles. Some of the results, such as pressure, maximum pressure and electric spark indicators, are shown as graphics. To calculate the speed of the flame propagation, specialised software processing the areas of the individual photos was used. The conclusions emphasize the results of relative air/fuel ratio, most favourable type of spark plugs and their gaps and location in the combustion chamber.