Research On Plasma Assisted Suppression Of Combustion Oscillation

Combustion oscillation often occurs in the internal operation of gas turbine,ramjet engine and incineration boiler,which threatens the stability and service life of combustion chamber.Plasma provides a new control strategy for combustion oscillation with rapid action,low energy consumption and little pollution while others have defects to some extent.Therefore,This research mainly includes four aspects: Preliminary test of plasma action on combustion oscillation,exploration of the influence law of AC discharge and dual-source excited plasma discharge on combustion oscillation phenomenon,and simulation of the closed-loop control of plasma assisted suppression of combustion oscillation.Firstly,the effect of plasma on combustion oscillation was preliminarily tested.The experimental system of a self-excited pulse combustor of the Helmholtz-type was developed.Based on the designed combustor,the influence of plasma action on combustion oscillation was preliminarily investigated.The effect of plasma affecting combustion oscillation was further studied through Ansys/Fluent software simulation calculation.Secondly,The experimental characteristics of AC discharge to suppress combustion oscillation was investigated.By studying the effect of AC discharge under different electrode conditions,the change rule of AC discharge under different electrode conditions is found.On this basis,the characteristics of the oscillating flame root/sidewall discharge were carried out.The influence mechanism of different types of discharge on the oscillating combustion was developed.Thirdly,the experimental characteristics of dual source excited plasma discharge action on combustion oscillation was investigated.The AC discharge frequency is too different from the flame oscillation frequency,which may cause the control of combustion oscillation to be ineffective.On the basis of the weak connection between the AC discharge and the oscillating flame,a method to regulate the oscillating flame synchronously by adding a pulse signal which is close to the frequency of the oscillating flame was designed.Based on this,control rules of combustion oscillation under different discharge excitation parameters were found by experimental investigation of discharge characteristics of dual-source excited plasma discharge and the characteristic test of action on combustion oscillation.Finally,the closed-loop by using plasma to regulate combustion oscillation was developed.The model between AC discharge plasma and the pressure in combustion is obtained by system identification.On the basis of this mathematical model,a closed-loop control loop for controlling combustion oscillation by discharge plasma is constructed by using software Matlab/Simulink,and the control effect of the closed-loop control loop is preliminarily tested.