Relationship between flame thickness and velocity based on thermodynamic three kernels in a constant volume combustion chamber

The aim of this study is to analyze the relationship between the flame thicknesses and velocity based on thermodynamic three kernels, including spark, arc and jet plasma discharges in a constant volume combustion chamber (CVCC). As the research method, a CVCC designed to ensure 400 cm3 of internal volume were developed by the authors to analyze the combustion characteristics. The compositions of combustion system include the spark plugs (conventional spark, arc and jet types), pressure sensor, temperature sensor, oxygen sensor, control circuit, hardware and high-speed camera. A pressure sensor for measuring the progressive combustion uses a type of Kistler 601CBA00250. It is verified that the discharge level of a jet plasma model is higher by about 3.8 kV then an arc plasma model and the combustion time is also faster than other plasma types. Moreover, in the signal analysis, the charging time in a jet plasma model starts to detect the signal from -0.11 ms to 0 ms and the charging voltage height is raised up to 40 kV due to being affected by stored energy of a capacitor. Consequently, the combustion performances of the arc and jet plasma discharges are noticeable in that flame thickness and velocity characteristics could be affected by ionized kernels in a CVCC. As the air-C3H8 equivalence rates, the progressive combustion and reaction by the arc and jet plasma discharges are more improved than the conventional spark discharge in a rarefied condition.