International Journal of Turbo & Jet-Engines

doi: 10.1515/tjj-2025-frontmatter4pmid: N/A

Zou, Zelong; Huang, Jinquan; Zhou, Xin; Lu, Feng

doi: 10.1515/tjj-2023-0026pmid: N/A

AbstractA novel degradation estimation method is proposed to draw out the engine performance deterioration rules of multiple rotational-component parameters simultaneous variations from available sensors. The proposed methodology consists of the extended Kalman filtering (EKF) and an enhanced optimization strategy. Gas-path parameter analysis on the impact of components performance is implemented to determine the key degradation feature. The unmeasured feature is randomly generated to estimate performance drifts of rotational components by the EKF group and steady model. The achieved performance parameters stream to the engine dynamic model to yield measurements’ estimated series, which are utilized to construct the fitness function. Thus, the optimization gains the unmeasured feature and the deteriorations of engine performance. This paper reaches simultaneous performance drifts of all components under the limited sensors. Simulation results show the suggested approach provides the precise unmeasured feature, and quantify variations in the simultaneous drift of engine performance during its usage.

Fan, Tianfu; Yu, Bing; Li, Songlin

doi: 10.1515/tjj-2025-0006pmid: N/A

AbstractTo reduce specific fuel consumption (SFC) of aero-engine, increase the combat radius of fighter jets, improve economic performance, and contribute to energy conservation and emission reduction, this paper proposes a hybrid optimization algorithm combining the chimp optimization algorithm (ChOA) and sequential quadratic programming (SQP). The algorithm ensures effective optimization while significantly reducing solving time. Focusing on a double bypass variable cycle engine, a sensitivity analysis is conducted to select optimal control variables. An intelligent optimization control system integrates ChOA-SQP with active disturbance rejection control (ADRC) for minimum SFC optimization. Results indicate that ChOA achieves a 7.28 % average SFC reduction, SQP achieves 6.71 %, and ChOA-SQP achieves 7.47 %, with ChOA-SQP reducing SFC an additional 0.57 % compared to SQP and 0.19 % compared to ChOA. Convergence time is only 24.25 % of ChOA and 109.75 % of SQP, with a convergence speed faster than ChOA and similar to SQP. The system transitions seamlessly to the minimum SFC point while ensuring safe engine operation, reducing SFC by 7.58 % at the subsonic cruise design point and 5.69 % at the supersonic cruise design point, with maximum thrust fluctuations of 0.87 % and 0.95 %, respectively.

Zhao, Jiayi; Zhao, Tianhao; Wang, Zhiheng; Xi, Guang; Zou, Hansen

doi: 10.1515/tjj-2025-0038pmid: N/A

AbstractThe transient characteristic of the disturbance from impeller, which is largely influenced by the stagger angle of IGV (inlet guide vane), significantly determines the performance of the vaned-diffuser downstream. Thus, the understanding of these phenomena is critical to avoid the degradation of diffuser performance including the dreadful rotating stall. The paper adopts both the experimental and numerical methods to investigate the significant change of the diffuser transient characteristics under large pre-swirl effects. The whole process of diffuser rotating stall, which origins from the vortex at rear of diffuser, is comprehensively studied. It is noticed that the variation of pre-stall behavior within vaned-diffuser closely relates to the pre-swirl angle, which is mainly reflected by the characteristic change of separated vortex from diffuser blade surface. Under large negative pre-swirl condition, the flow non-uniformity between main and splitter blades of impeller significantly grows. It applies more influences on the transformation of vortex from rear to semi-vaneless region of diffuser and triggers the final stall precursor much earlier. Besides, a novel stall warning method based on the non-uniformity coefficient C has been developed and the prediction errors are controlled lower than 2 % in most cases.

Xu, Decheng; Zhang, Xiang; Zhang, Zhongzhi; Cheng, Jinxin; Meng, Fanzhen

doi: 10.1515/tjj-2025-0033pmid: N/A

AbstractBased on the sparse PC-Kriging method, a high-fidelity surrogate model was constructed to map the geometry of a stepped labyrinth seal to its leakage characteristics. Based on this surrogate model, Monte Carlo sampling was employed to analyze the impact of geometric errors on the uncertainty of the seal’s leakage characteristics and conduct sensitivity analysis. The results indicate that within a 99.7 % confidence interval, the maximum discharge coefficient can reach 0.584; compared to the baseline value of 0.52118, the worst-case scenario could lead to an approximate 12.1 % increase in the discharge coefficient, significantly increasing leakage. Sensitivity analysis reveals that the tip clearance of the fifth tooth exhibits the highest sensitivity to the discharge coefficient, approaching 80 % and dominating the response, while the remaining parameters show lower sensitivity, with 47 of them having sensitivities close to zero.

Gorla, Rama Subba Reddy; Forster, Edwin; Pentecost, Benjamin

doi: 10.1515/tjj-2025-0019pmid: N/A

AbstractThe uncertainty propagation and transient heat transfer from an extended surface are studied. The stochastic Biot number, the fin number and initial and convection boundary conditions define the uncertainty propagation for the temperature distribution in the extended surface. The amplitude of the propagated uncertainty was observed to have a transient evolution. The uncertainty may increase or decrease depending on the stochastic input parameters. Results are presented for the variation of temperature and heat flux due to uncertainties in the initial condition and conditions at the boundaries where heat is rejected.

Gudla, Babji; Pujari, Arun Kumar

doi: 10.1515/tjj-2024-0108pmid: N/A

AbstractFilm cooling is critical in protecting gas turbine nozzle guide vanes from extreme thermal loads, enhancing their durability and efficiency. Understanding the interaction between aerodynamic performances and cooling effectiveness is essential for optimizing vane design. This study investigates the aero-thermal characteristics of a film-cooled gas turbine nozzle guide vane under subsonic conditions. ANSYS simulation software was used for the computational study, and the results were experimentally validated using a low-speed cascade wind tunnel setup with a coolant flow unit. The study explored how film cooling in different regions of the vane (Suction surface, pressure surface, leading edge) influences total pressure losses. Findings indicated that both effectiveness and loss coefficient increased with rising MFR. Specifically, an increase in MFR from 0.004 to 0.005 led to a 1.3 % improvement in cooling effectiveness and a 2.57 % rise in pressure loss coefficient. Similarly, when the MFR increased from 0.005 to 0.006, effectiveness improved by 10.86 %, and the total pressure loss coefficient increased by 3.25 %.

Gorla, Rama Subba Reddy; Pentecost, Benjamin; Forster, Edwin

doi: 10.1515/tjj-2025-0029pmid: N/A

AbstractThe uncertainty propagation and transient heat transfer from a flux-base extended surface are studied. The stochastic Biot number, the fin number and initial and convection boundary conditions define the uncertainty propagation for the temperature distribution in the extended surface. The amplitude of the propagated uncertainty was observed to have a transient evolution. The uncertainty may increase or decrease depending on the stochastic input parameters. Results are presented for the variation of temperature due to uncertainties in the initial condition and conditions at the boundaries where heat is rejected.

Roga, Sukanta; Anand, Abhinav; Jha, Rishabh; Sumithran, Varun

doi: 10.1515/tjj-2025-0036pmid: N/A

AbstractThis investigation examines the performance of Hydrogen- and Kerosene-fuelled Scramjet combustors, emphasizing fuel injection strategies and combustion efficiency. Experimental findings and simulation results showed that hydrogen fuel achieved a combustion efficiency of 96 % when running in struts shortened by 45 % with proper modifications. Dual-strut fuel injection systems deliver better performance levels because their efficiency reaches 92 % compared to setups at 65 %. When injecting across the flow or creating cavities, the mixing becomes more efficient because this technique generates powerful vorticity along the streamwise direction and creates recirculation zones that strengthen flame stability and decrease flow pressure. Combustion in recirculation areas reached maximum temperatures exceeding 2950 K, which ensured stable burner operation. Hydrogen combustion during Mach 4.5 operations led to the minimum pressure loss rate and maximum thermal efficiency outcome. The study confirms that hydrogen functions as the best renewable fuel for Scramjet propulsion, which leads to the development of aircraft systems that are both reusable and environmentally beneficial.

Zhang, Xinzhe; Yu, Bin; Jiang, Yuanyuan; Li, Guoju

doi: 10.1515/tjj-2025-0045pmid: N/A

AbstractThis study employs the fluid-structure interaction (FSI) method to quantitatively evaluate the impact of different tip clearances on compressor blade performance, focusing on the influence of flow fields on structural behavior. The computational fluid dynamics (CFD) models utilized herein have been corroborated with experimental data. The vibration characteristics of blades were obtained based on the Campbell diagram, and fatigue life prediction was finally carried out. The results indicate that as the blade tip clearance increases from 0 times the design clearance to 2 times the design clearance, the tip vortex in blade tip flow field gradually strengthens, leading to a decrease in pressure ratio and efficiency, while the stable operating range of blade is shortened. Blade vibration modes are predominantly influenced by centrifugal loads, with tip clearance exerting a minor effect on these characteristics. The Campbell diagram indicates that the blade has low resonance margins at the design speed ranges of 54–59 % and 78–83 %, which are prone to resonance. After FSI calculations, it was found that the increase in blade tip clearance enhances the wing tip leakage vortex, reduces the aerodynamic load on blade, gradually reduces the maximum deformation of blade, and increases the fatigue life of blade.