Research On The Flow Field Mixing Characteristics In The Combustor Excited By Synthetic Jets

Synthetic jet actuactors were placed in a kind of engine combustor model in this paper, themixing flow field in the combustor excited by the synthetic jets were numerical simulated. Obtain exittemperature distribution under different synthetic jet parameters, thus provide some theoreticalfoundation for the application of synthetic jet on engineering.The research content including: CFD commercial software was used to simulated the combustionprocess in3D combustor to get the combustor exit temperature distribution. The flow field andtemperature field distribution were set as boundary conditions of2D model. The influence ofexcitation parameters and geometrical parameters on combustor mixing effects was analyzed.Furthermore, synthetic jet actuators were placed on the mixing hole location, change the frequencyand amplitude to analyze their influence on combustor exit temperature distribution.The results show that synthetic jets can significantly enhance the mixing of flows in the field,decrease the high temperature core area, and improve the exit temperature distribution. Actuators arecontinuously blowing and inhaling the fluid around the cavity to produce a sustained jet. Complexvortices structure emerges in combustor and its strong convection enhances the mixing of flows in theflow field. The peak velocity of jet from actuator nozzle occurs under the Helmholtz frequency, butthe flow field could not get the best mixing effect and exit temperature distribution. Under thestructure of the combustor given in this paper, the bigger frequency is not always better. As theamplitude increases, the velocity of jet increases, and the mixing effect gets better. The otherparameters stay constant, the position of actuator closer to the entrance, the better exit temperaturedistribution could be obtained. When the two actuators were arranged relative to each other, the bestexit temperature distribution could be obtained under0.5T phase difference. After the mixing holeswere replaced by synthetic jet actuators, synthetic jet can improve the uniformity of exit temperatureto some extent. Change the frequency and amplitude could obtain the same rule compared with the2Dsimulation.