l. deng

The S1 stream surface inverse method for a single-stage axial transonic compressor was developed and studied under the guidance of the quasi-three-dimensional viscous design theory, based on computational fluid dynamics (CFD), in order to establish and solve governing equations. The re--adjusted load distribution of the S1 stream surface was imposed to obtain a special profile for the rotor, which is known as S-shaping. This changed the structure and weaken the strength of the shock due to the pre-compression effect. In order to match the inlet flow angle of the downstream stator, inverse modification for multiple S1 stream surfaces of the stator blade was conducted in the present study at the same time. As it is known, the S-shaped profile is commonly applied to supersonic flows. Therefore, NASA stage 37 was selected as the design case to verify whether the present inverse method is effective and reliable. Stage 37 was re-designed by stacking five S1 stream surfaces. The profiles of these surfaces were renewed through the inverse design. The results revealed that, compared to the prototype, the aerodynamic performance of the re-designed one was apparently promoted within the stable working range. The adiabatic efficiency at the design point increased by approximately 0.4%, and the pressure ratio improved by approximately 4.5%. In addition, analysis result for the characteristic line revealed that the performance of the redesigned blades at off-design points significantly improved.

Experiments on a two-phase rotating detonation combustor operating with gasoline and high total temperature air were conducted to investigate the initiation characteristics, operation mode, and propagation characteristics of a two-phase rotating detonation wave (RDW). The outer diameter, inner diameter, and length of the annular combustor were 204 mm, 166 mm, and 155 mm, respectively. The initiation characteristics, operation mode, and propagation characteristics of the two-phase RDW were studied by varying the total air temperature. The experimental results show that the initiation time of the RDW first decreases and then increases with an increase in the total air temperature and reaches an extreme value at a total air temperature of 713 K. Four operation modes (failure, intermittent detonation, single wave, coexistence of double wave collision, and single wave) of the detonation combustor were found for different total air temperatures. The effect of the total air temperature on the peak pressure stability and propagation frequency of the RDW was studied in detail. From the results, the effect of the equivalence ratio on the working characteristics of a rotating detonation engine (RDE) was investigated at a total air temperature of 713 K. Four detonation propagation modes (sporadic detonation, intermittent detonation, single-wave mode, coexistence of double-wave collision and single wave) were obtained in the combustor. When the equivalence ratio was 0.52, the detonation initiation failed. The pressure characteristics in the combustor and propagation frequency of the RDW were studied with different equivalence ratios. In addition, a long-duration test was performed for 3 s to verify the continuous working feasibility of the two-phase RDE.