Breaking through the limit of conventional compression and combustion, wave rotor and trapped vortex combustors are able to improve the thermal efficiency of gas turbines. Detailed two-dimensional numerical simulations based on Ansys Fluent were performed to study the flow and combustion characteristics of the wave rotor–trapped vortex combustor system. The calculated pressure characteristics agree with the experimental results giving a relative error for average pressure of 0.189% at Port 2 and of 0.672% at Port 4. The flow stratification characteristics and the periodic fluctuations were found to benefit the zonal organized combustion in the trapped vortex combustor. For the six cases of different rotor speeds, as the rotor speed increased, the oxygen mass fraction at the combustor inlet rose and then fell. The proportion of exhaust gas recirculation fell at first and then rose, and the combustion mode became unstable with the dominant frequencies of the fluctuations increasing.

Pulsating injection offers a potential strategy for controlling fuel sprays in aerospace propulsion systems, yet the effects of pulsation amplitude on liquid-jet breakup and spray characteristics in gaseous crossflow remain insufficiently understood. In this study, a volume-of-fluid (VOF) method with adaptive mesh refinement (AMR) is employed to investigate aviation kerosene jets in a subsonic crossflow and quantify amplitude effects on atomization. The results show that increasing the amplitude intensifies local liquid-column deformation and promotes earlier primary breakup. As the pulsation amplitude ($\beta$) increases from 0.05 to 0.25, the surface wavelength remains nearly unchanged, whereas the necking ratio decreases by 55.7%, and the primary breakup distance is reduced by 16.79–49.26% relative to the steady jet. At a downstream distance of 70 injector diameters ($x/d=70$), the penetration depth of the pulsating jets is 9.37–14.38% greater than that of the steady jet and reaches its maximum at $\beta =0.15$ under the present conditions. For the pulsating jets, earlier primary breakup does not necessarily produce smaller downstream droplets. Under the common numerical resolution, the resolved downstream droplet population shows an overall shift toward larger sizes as the pulsation amplitude increases, as reflected by the increasing trends of the Sauter mean diameter (SMD), number-based median diameter ($D_{N50}$), and number-based 90th-percentile diameter ($D_{N90}$). These results clarify the distinct effects of pulsation amplitude on primary breakup, spray penetration, and downstream droplet size, providing guidance for amplitude selection in active fuel-spray control.

Airblast nozzles are widely applied in advanced aeroengine combustors, and their crucial physical phenomena can be simplified to the disturbance and breakup of an annular liquid jet with swirl air. Therefore, the performance of the nozzle is closely related to the primary breakup process, and the linear instability theory provides a theoretical framework for elucidating the primary breakup process. The research focuses on the swirling airflow interacting with the annular liquid jet and derives the dispersion equation for the annular liquid jet based on the linear instability. Through numerical solutions of this dispersion equation, a detailed parametric analysis is conducted. The parametric study shows several key findings. Increasing air density, axial gas velocities (both inner and outer flows), and the rotational Weber numbers promote breakup efficiency. Reducing the liquid jet thickness also enhances breakup efficiency. These changes result in a decrease in primary breakup length and mean droplet diameter. In the process of the decrease in the liquid jet thickness, the dominant force of primary breakup will be changed from the surface tension of the liquid to the aerodynamic force. The swirl air will make the dominant modes of primary breakup change from the axisymmetric modes to the helical modes.

To achieve the three-dimensional reconstruction of smoke, this paper combines data calculation and processing by taking photos from multiple angles and utilizing computed tomography imaging technology. The SART algorithm and TV regularization are selected as reconstruction algorithms. Since the semi-convergence phenomenon exists in the separate SART algorithm and the lowest point of error in the calculation process is predictable, which can be used as the entry point for the coupling of the SART algorithm and TV regularization, this paper proposes a method of dynamically adjusting the step size of the gradient descent of the TV regularization to ensure tha a lower reconstruction error is maintained during the whole process of the calculation, under the condition that the relaxation factor of the SART algorithm is kept unchanged. Comparative evaluation against established methods demonstrates that the proposed approach achieves a statistically significant improvement in accuracy and noise reduction, coupled with enhanced stability and robustness. Especially, the effect is even more pronounced when there is input noise.