Jul 2026· Journal of Engineering For Gas Turbines and Power· Vol 148· 0 citations
Abstract
Research has shown that rotating detonation turbine engines have the potential to enhance aero-engine performance. However, the rotating back-propagation pressure wave (RBPW) generated by the detonation-based combustor can adversely affect the upstream compressor. In this study, this unsteady backpressure was simulated using a user-defined function (UDF), and its impact on a centrifugal compressor was numerically investigated. The results show that, under single-wave RBPW, both the total pressure ratio and isentropic efficiency declined at the same mass flow rate compared to steady-state conditions. Variations in the characteristic parameters of the RBPW resulted in shifts of the compressor's operating point. A higher-pressure distortion index caused a greater deviation from the original characteristic line. Increasing the propagation frequency or using a multi-wave configuration mitigated these adverse effects. Under four-wave excitation, compressor performance exceeded that of steady operation. Finally, the stability boundaries of the compressor under RBPW were defined in terms of constant flow rate and constant power constraints.
Abstract To mitigate turbine performance degradation caused by the highly pulsating exhaust from a pulse detonation combustor (PDC) in pulse detonation turbine engines, a shock divider was employed in this study to regulate the detonation gas. An asymmetric dual-channel shock divider was designed and manufactured, and a coupled experimental test platform consisting of the PDC, the shock divider, and a turbocharger was established. Comparative experiments with and without the shock divider were conducted over a PDC operating frequency range of 10 Hz–30 Hz. The experimental results indicate that the shock divider can effectively reduce the pressure pulsation amplitude of the pulse detonation gas, thereby enabling stable coupled operation of the three components across the entire range of operating conditions. Furthermore, the shock divider can enhance the turbine rotational speed, output power, and efficiency under all operating conditions. Specifically, the relative increase in turbine power reaches up to 58.1 %, and the absolute increase in turbine efficiency reaches up to 13.7 %, with the optimal enhancement effect observed at 20 Hz. The findings of this study demonstrate that the shock divider is an effective approach to improving turbine performance under pulse detonation gas impact.
Kexin Liu, Longxi Zheng, Dingding Wang et al.· International Journal of Tur...· 0 citations
Rotating Detonation Engines (RDEs) offer a promising path toward more efficient and compact propulsion and power systems. However, the highly unsteady and transonic outlet flow generated by the detonation process, characterized by oblique shock wave patterns, introduces significant challenges for turbine integration and overall performance. The present work focuses on the impact of the oblique shock waves exiting the rotating detonation combustor (RDC) on a supersonic inlet high-pressure turbine stage. The analysis examines how the shock pattern, the number of detonation fronts, and their rotation direction affect the unsteady aerodynamics and the overall turbine performance. In addition, the effect of shock waves on the stator and rotor unsteady loads is investigated to provide a preliminary aeromechanical assessment of the supersonic turbine. Full-annulus unsteady simulations were performed to capture the complex RDC–turbine interaction and its effects on blade loading and flow structures. The numerical framework has been validated against a previous Large Eddy Simulation (LES) analysis of the turbine stage under RDC-representative conditions. The comparisons highlight the key mechanisms driving shock–turbine interactions, showing how shock synchronization and rotation direction affect turbine efficiency and power extraction. These findings provide valuable insights into the design configurations and coupling scenarios of turbines operating under detonation-based flow conditions.
L. Pinelli, Pietro Biagini, M. Marconcini et al.· Journal of turbomachinery· 0 citations
The main reason for limiting the working flow range of the compressor is the unstable flow phenomenon of the compressor working at a small flow rate, including stall, surge, and rotational instability. Among them, the rotating stall phenomenon is particularly prone to occur during the operation of centrifugal compressors. In this paper, a three-stage nitrogen centrifugal compressor is taken as the research object, and the dynamic development process of rotating stall in the diffuser is captured by full-channel numerical calculation. After research, the leading-edge vortex at the diffuser inlet is the cause of rotating stall. In the throttling process, the backflow in the diffuser causes the channel blockage and the stall phenomenon triggered by the leading-edge overflow. There are six stall channels in the first-stage diffuser and nine stall channels in the second-stage diffuser. The propagation direction is the same as the rotation direction of the blade, and the propagation speeds are 4.348% and 5.26%, respectively.
Zhuhai Zhong, Xiaodan Zhang, Kunlun Bai et al.· Fluids· 0 citations
To suppress the flow-induced vibration of a single-stage single-suction centrifugal pump (rated head 5 m, flow rate 30 m
3
/h, rotational speed 1000 r/min), the key impeller parameters were taken as design variables and screened via the parameter sensitivity analysis method in this study. The internal flow field was solved using the Reynolds-Averaged Navier–Stokes (RANS) approach with the SST k–ω turbulence model, implemented in the commercial CFD code ANSYS Fluent. With pump efficiency and the sample standard deviation of circumferential tangential velocity uniformity at all nodes of the impeller outlet set as the optimization objectives, and pump head as the constraint condition, the Kriging surrogate model combined with the Non-dominated Sorting Genetic Algorithm II (NSGA-II) was adopted to conduct the optimal design of the impeller structure. The results show that the head and efficiency of the optimized pump are increased by 10.8% and 2.7%, respectively. The pressure pulsation amplitudes associated with the blade-passing frequency (BPF) at the volute tongue are significantly reduced, with a 36.1% decrease at the volute tongue and a 22% decrease inside the volute, which effectively mitigates the rotor-stator interaction (RSI). Comparisons of the internal flow fields confirm the suppressed secondary flows, reduced turbulent kinetic energy, weakened jet-wake effects, and improved unsteady performance of the optimized pump, thus verifying the feasibility and effectiveness of the proposed optimization strategy.
Jiafu Guo, Xinxiang He, Abdul Mutalib bin Leman et al.· Proceedings of the Instituti...· 0 citations
Shaftless pump-jet propulsors offer high propulsion efficiency but also generate significant flow-induced noise due to complex internal rotating flows. This study investigates blade deflection angles of ‒2°, 0°, and +2° through unsteady simulations with the RNG
k–ε
turbulence model, supported by experimental validation. Dominant noise frequencies are extracted using Fast Fourier Transform, and a hybrid CFD-acoustic method based on Lighthill’s acoustic analogy is applied. Results show that as the deflection angle increases from ‒2° to +2°, thrust and efficiency decrease slightly but remain acceptable. The +2° configuration yields more concentrated and continuous wake vortex bands, suppresses large-scale vortices in impeller passages, and enhances rotating flow coherence. Noise energy is primarily concentrated below 1000 Hz, with dominant peaks at the shaft frequency and its harmonics. At +2°, both the dominant-frequency sound pressure level and the overall sound pressure level decrease at most monitoring points, achieving a maximum reduction of approximately 1.69 dB without significant performance loss.
Hou-lin Liu, Yang Zhao, Xianfang Wu et al.· Proceedings of the Instituti...· 0 citations
This study numerically investigates the effect of low-momentum blowing applied to a toroidal propeller on aerodynamic performance and aeroacoustic characteristics. A Delayed Detached Eddy Simulation (DDES) approach coupled with the Ffowcs–Williams and Hawkings (FW–H) acoustic analogy is employed to resolve unsteady flow structures and predict far-field noise signatures. Two configurations are examined at 3000 revolutions per minute (RPM): a baseline propeller and one equipped with active flow control (AFC). The results show that the introduction of AFC produces negligible changes in thrust, torque, and figure of merit (FM), indicating that equivalent aerodynamic performance is maintained. In contrast, noticeable acoustic benefits are achieved. Significant reductions in primary tonal noise and overall sound pressure level (OASPL) are observed along the propeller axis direction, with a maximum tonal reduction of approximately 6 dB and an OASPL decrease of up to 1.8 dB. Flow-field analysis using Q-criterion iso-surfaces and z-vorticity contours reveals that blowing weakens coherent vortex structures near the upper surface of the back blades around 0.75
R
. The weakened vortical activity reduces unsteady surface pressure fluctuations, thereby attenuating dipole-type acoustic sources responsible for dominant axial radiation.
M. Chen, Omar D. Lopez Mejia, Jielong Cai et al.· International Journal of Aer...· 0 citations
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