Experimental And Numerical Simulation Of Electrical Characteristics Of Laminar Flame Quenching

With the rapid development of micro electromechanical system, the demand for the miniature energy system with smaller size structure and more power density is more and more urgent. The microscale combustion power system has received a widespread attention due to the characteristics of high energy density. However, microscale combustion produces a lot of new problems compared with conventional combustion. Micro-scale combustion can’t maintain stable, and quenching always happens. At the same time, since the flame itself is a kind of weakly ionized plasma, the flame of hydrocarbon fuel contains many charged particles which are directly related to the chemical reaction, such as CHO+, H3O+, e, OH-. When the quenching occurs, the speed of flame is reduced and stop spreading to the surface in the end, which can cause the change of the number and the distribution of charged particles mentioned above. Therefore, the study on electrical characteristics of flame quenching is really necessary.This subject analyzes the electrical characteristics of laminar flow steady flame quenching from the aspects of theory, experiment and numerical simulation. and acquires the change rules of the laminar flame quenching parameters. The research results are as follows:Designing and building the electrical characteristic test bench of the laminar flame quenching. This subject adopts the controlling variable method for experiments. In the aspect of theory, the frequency values of nearly collision is obtained from the molecular kinetic theory, and by using the plasma theory, the order of magnitude of the electric conductivity of flame on the condition that small DC electric field is measured, which is 10-8.Using the controlling variable method, only change the voltage value between the burner and quenching plane. By using 20 V, 40 V, 60 V, 80 V respectively, some conclusions are obtained: the voltage load direction influences the current size; the current is larger when the voltage loaded on the burner is negative; the current value increases with the increase of voltage. Within a certain range, the resistance value in the same height of flame remains the same, and no changes with the change of the voltage.The influence of the materials of quenching surface on electrical characteristics of flame quenching is small. In quenching, with the decrease of distance distance, the flame upward propagation is hindered, and the high temperature zone of the flame moves toward the left and the right sides of the burner, and the maximum temperature in the reaction region is reduced. The content of CO2 increased first and then decreased, and the content of CO increased at first and then decreased.With the increase of air content, the maximum temperature of the flame quenching is gradually increased with the increase of the air content in the range 50 mm. Region of high temperature flame with air volume increased gradually toward the middle area concentrated; flame quenching of the axial velocity gradually increased; gradually decreases with the mass fraction of flame quenching of CO, and CO mass fraction had the highest values of position showed a downward trend; flame quenching when the mass fraction of CO2 maximum value decreased gradually, flame of CO2 mass fraction of larger area with the air volume increased gradually toward the middle area concentrated.