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
In conventional aero-engine testing, the combustor and afterburner are usually evaluated separately, which increases cost and energy consumption because two high-temperature sources are required. This study proposes a flange-type mixer for integrated testing, in which ambient air is transversely injected to cool the combustor exhaust through jet-induced mixing. RANS simulations were conducted for 16 flange configurations at a jet-to-mainstream temperature ratio of 0.14 and a mass flow ratio of 1.0, and the numerical approach was assessed against experimental measurements. The results show that mixing is strongly affected by the number of holes and the momentum ratio, and is further influenced by the inlet-pipe-to-hole feeding characteristics of the flange. Recirculation occurs only when the momentum ratio is 3009 and the number of holes is 36 or less, but it does not result in distinctly better mixing. Meanwhile, azimuthal asymmetry and hole-to-hole maldistribution may, in some cases, enhance downstream mixing by producing alternating strong and weak jets and locally increasing penetration. To unify jet-trajectory behavior across configurations, a nondimensional analysis was conducted, and a modified Holdeman-type trajectory correlation was developed for the present confined circumferential injection. In addition, a feeding-imbalance index was proposed. When combined with the penetration metric, it improved the correlation with mixing performance. These findings provide guidance for the design of compact mixers for high-enthalpy integrated test systems.
Hongyu Ju, J. Suo, Hongxi Liang et al.· Journal of turbomachinery· 0 citations
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