The burned gas with external environment in the pulse detonation engine chamber turbulent mixing model

1Zolotko, ОE, 1Zolotko, ОV, 1Moroz, Yu.I, 1Sosnovska, ОV
1Oles Honchar Dnipro National University, Dnipro, Ukraine
Space Sci. & Technol. 2018, 24 ;(6):16-25
Publication Language: Ukrainian
Abstract: 
The mechanism for controlling high-speed burned gas is based on the creation of a controlled gas atmosphere in the nozzle. The features of this mechanism require a detailed study of the change in the polytropic exponent of the gas in the region behind the shock front. The effect of the wave interaction is considered in the case of a significant difference between in the ratio of the specific heats of the burned gas and the gas in the nozzle. The oscillation process generation mechanism is analyzed. This process is determined by the interaction of reflected waves from the contact surface and the chamber wall. The pressure peaks periodically appear on the thrust wall due to wave interaction and the specific thrust impulse of the detonation engine increases. This effect is observed in experimental researches. The known theoretical models for calculation specific impulse of detonation chamber with straight cylindrical nozzle were considered. The inherent limitations of these models were analyzed.
               A new theoretical model is proposed. This model is based on the turbulent mixing of a burned gas with a gas in nozzle analysis. The mathematical model of the process in the detonation engine chamber is based on two-dimensional non-stationary Euler equations. The numerical integration of the differential equations system was realized by using a finite-difference TVD scheme. The results of the numerical-theoretical simulation correspond to experimental data. New model allows to make a reasonably choice of the nozzle type for a multimode engine detonation chamber when an environmental condition is substantially changed. A practical application example was made for the best choice from the three different nozzles (straight cylindrical nozzle, nozzle with high expansion rate and sliding nozzle).
Keywords: detonation, nozzle, numerical simulation, pulse detonation engine, ratio of specific heats, theoretical model, turbulence