Study On The Interaction Mechanism Between Continuous Rotating Detonation Wave And Turbine Blade

Due to the characteristic of pressure-gain which could enhance the thermodynamic efficiency,the continuous rotating detonation combustor was expected to further improve the performance of gas turbine system.In this paper,taking the coupling system of continuous rotating detonation combustor and turbine as the research object,the interaction mechanism between continuous rotating detonation wave and turbine blade was studied by means of numerical simulation and experiment.The main work is as follows:Based on the method of Unsteady Reynolds-Averaged Navier-Stokes(URANS)and the k-ω turbulence model of Shear Stress Transfer,was built up to study the interaction between rotating detonation wave and turbine cascade and analyze the suppression effect of turbine cascade on high frequency detonation pressure oscillation.Hydrogen and air were employed as the fuel and oxidant,respectively.The results showed that the subsonic gas flow in the combustor was accelerated by the turbine cascade at 50% blade heights,and the Mach number of the local area behind the oblique shock wave increased more obviously.The oblique shock wave interacted with the leading edge,pressure surface,suction surface and trailing edge of the turbine’s stator blades and rotor blades.Due to the different transport directions of rotating detonation waves,the oblique shock waves were perpendicular or parallel to the stator blades and two different wave structures were formed.It was obvious that the turbine cascade can suppress the high frequency pressure oscillation,and the amplitude attenuation rate of high frequency pressure oscillation in the upstream and downstream of turbine cascade can be up to 80%.When the oblique shock wave and turbine stator blades were parallel to each other,the suppression effect of turbine cascade on pressure oscillation was more obvious than that when the oblique shock wave and turbine stator blades were vertical to each other,and the suppression effect of rotor blades on pressure oscillation was more prominent.The characteristics of the flow field and the propagation parameters of rotating detonation waves at 10%,50% and 90% blades height were compared.The results revealed several similarities and differences in wave system structures of the three cases.The pressure attenuation rate was-3.9% in the downstream of the stator blades at 90%blade height,while the value was positive at other two cases.At 10% and 50% blades height,the pressure attenuation rates were similar in the downstream of stator blades,rotor blades and turbine cascades,which were higher than that at 90% blade height.The coupling test system of continuous rotating detonation combustor and axial turbine was built,and the hot state experiment of continuous rotating detonation combustor and the cold state experiment of continuous rotating detonation combustor and axial turbine were carried out.The results showed that when the propellant total flow rate was 421.9g/s,the successful initiation and long-time stable propagation of detonation wave in single-wave mode were realized.The dominant frequency of the detonation wave was 6244.5Hz and the calculated velocity was 1723.7m/s,which was12.2% less than the theoretical Chapman-Jouguet(C-J)velocity.It was found that the static pressure varied in different circumferential positions upstream of the stator blades,and the static pressure was higher near the pressure surface.As the air flow rate was increased from 200g/s to 500g/s,the static pressure in the upstream and downstream of the turbine gradually rose,while the rising speed in the upstream was more rapid than that in the downstream.With the increase of flow rate,the pressure attenuation value increased from 0.043 bar to 0.197 bar,and the pressure attenuation rate increased from4.16% to 15.50%.