Experimental research on influence of turbine guide vane on propagation characteristics of rotating detonation wave

Abstract

Detonation is a supersonic combustion in which a shock wave propagates driven by an energy release in a reaction zone. Compared with deflagration, detonation has high thermodynamic efficiency and fast heat release rate. The traditional propulsion system based on the isostatic combustion is relatively mature, and its performance is very difficult to further improve. Therefore, detonation is expected to improve the performance of the propulsion system. Replacing the isobaric combustion chamber of turbojet engine with rotating detonation combustor can not only improve the combustion chamber efficiency, but also reduce the number of compressor stages, reduce the weight of engine and simplify the structure of engine. In order to study the operation characteristics of rotating detonation combustor with a turbine guide vane, a series of experiments is conducted, with hydrogen used as fuel and air as oxidant at different equivalence ratios. Based on the signals of high frequency pressure sensor and static pressure sensor, the operation mode of rotating detonation combustor and the effect of a turbine guide vane on the inhomogeneous and unstable detonation products are analyzed in detail. The experimental results show that when the equivalent ratio is less than 0.5, the rotating detonation combustor operates in a rapid deflagration mode and the pressure of combustion wave is about 0.6 bar (1 bar = 10<sup>5</sup> Pa). The rotating detonation combustor begins to operate in an unstable rotating detonation mode when the equivalence ratio increases to 0.6, and the pressure of detonation wave is about 6 bar. The rotating detonation combustor operates in a stable rotating detonation mode when the equivalence ratio reaches 0.82, and the pressure of detonation wave is about 16.3 bar. In addition, the propagation velocity gradually increases and the stability improves with the increase of the equivalence ratio. The oblique shock wave interacts with the turbine guide vane, and part of the oblique shock wave is reflected back to combustor, which causes some small pressure fluctuations in combustor. The turbine guide vane can obviously suppress the amplitude of pressure oscillation, but has little effect on the frequency of pressure oscillation. The upstream and downstream static pressure of the turbine guide vane increase simultaneously with equivalence ratio increasing. Furthermore, the static pressure of detonation products decreases obviously after passing through the turbine guide vane.

Numerical investigation on the interactions between rotating detonation wave complex and planar turbine cascade

“…They also discovered that there is a certain degree of low-frequency pressure oscillations after passing through the TGV. Wei et al 22,23 investigated the impact of turbine guides on the rotating detonation wave propagation characteristics at various equivalent ratios and discovered that the guide action considerably decreased the amplitude of the pressure oscillations and associated static pressure. An experimental model that combines the RDE and TGV was developed by Wu et al, 24 and while the TGV had an attenuating effect on the pressure oscillations caused by rotating detonation waves and turbine blade action, the reflected shock waves (RSW) still propagate into the combustor.…”