Search Results (136)

To reduce high 1× vibration during staged speed-up of a Turbine Power Simulator (TPS) rotor, a staged incremental on-site balancing method based on a Genetic Algorithm–Salp Swarm Algorithm (GA–SSA) is proposed. SSA is a swarm-intelligence optimizer inspired by salps, gelatinous marine organisms that move collectively in chains. A one-dimensional Timoshenko-beam rotor model with lumped disks and equivalent bearing supports is established and validated using a three-dimensional ANSYS model. From meshes M3 to M4, the equivalent speed associated with the first lateral natural frequency changes by 0.23%. The first three critical-speed errors are 6.75–8.80%, while baseline 1× vibration-amplitude errors remain below 10% and phase errors below 7.1%. Speed-specific influence coefficients are then extracted to formulate a staged incremental balancing model based on the current measured vibration and cumulative correction state. In GA–SSA, the final GA population initializes SSA, and the historical GA best is used as the initial Food. Under equal function-evaluation budgets and 30 paired runs, GA–SSA shows search performance comparable to GA and improves the stability of standalone SSA. On-site tests at 10,358, 25,558, and 38,333 rpm reduce 1× vibration at both rotor ends by 79.0–86.4%, confirming the method’s engineering applicability. Full article

Hirth couplings connect gas-turbine rotor discs and transmit torque, making them critical to efficient energy conversion and power output. To address the current lack of strength research, limited optimization studies, and inefficient optimization methods for Hirth couplings, a Hirth Coupling Strength Prediction Graph Convolutional Network (HSP-GCN) is proposed for multiple mechanical field reconstruction and structural optimization. HSP-GCN can rapidly reconstruct the displacement, stress, and contact pressure fields on the Hirth tooth surfaces according to structural parameters. Its rapid and accurate performance superiority is demonstrated through comparisons with deep neural network and convolutional neural network models. To the best of our knowledge, this is the first instance that a neural network-based surrogate model has been used for field reconstruction and performance prediction of Hirth couplings. The results show that the field mean absolute errors are below 0.02 for all reconstructed fields except u_x. The relative errors of the maximum von Mises stress and maximum contact pressure are generally within ±5%, with an error of −5.76% observed in one representative case near the boundary of the design space. Meanwhile, a multi-constraint optimization method for Hirth couplings based on HSP-GCN is proposed. The optimized designs reduce the maximum von Mises stress by 15.4%. This study can provide an effective and novel tool for accelerating analysis and optimization. Full article

The paper examines the impact of gas turbine engine component manufacturing quality on the efficiency criteria of its life test. Known methods for selecting test parameters apply maximum damageability equivalence and minimum test time as test efficiency criteria. This study also proposes taking into account the maximization of engine life cycle profits through the proper selection of test parameters. Engine components that determine its life were selected: the turbine blade, rotor bearing, reducer driving gear, fan bearing, and DC and AC generators. Both the mathematical expectation and variance of the quality parameters were varied during the study. The manufacturing quality of engine components and assemblies is characterized by geometric, mechanical, and physical parameters. These parameters include bearing fit diameters, initial radial clearance, turbine blade geometry, mechanical properties and gear shape, generator insulation quality, and others. Selection of parameters was based on the life cycle simulation model. The following results were obtained in the course of the study within the framework of modeling: (1) Manufacturing accuracy has a more significant impact on test results than deviations from mean values of initial state parameters; (2) under the accepted assumptions, despite the fact that variation in production parameters from the standard values does not affect the comparability of test results, they lead to an acceleration of the testing process. At the same time, this entails a decrease in overall economic efficiency throughout the entire life cycle of the product; (3) according to the obtained results, the overall profitability of a production run of engines is primarily determined by the quality characteristics of the turbine blades, and least of all by the fan bearing quality parameters. Full article

The ultra-large steam turbine rotor and heavy gas turbine disk are key components of power stations. They are manufactured from very large ingots, and extremely low strain rates are used during forging. In this study, a high-strength CrNiMoV steel, 25Cr1Ni4MoV, was hot-compressed at 1000–1200 °C and strain rates of 0.01–0.0001 s⁻¹, and the resulting deformed microstructures were observed. The peak stress ranged from 17 to 72 MPa. The hot deformation equation was obtained, and the activation energy for deformation was determined to be 329 kJ/mol, which was lower than that reported in previous studies due to the extremely low strain rate. The deformation mechanism is dynamic recrystallization even at a strain rate of 0.0001 s⁻¹. The critical strains for complete dynamic recrystallization were determined. The dynamic recrystallization grain size increased slowly with decreasing ln(Z), where Z is the Zener–Hollomon parameter, within the ln(Z) range of 22–27. However, when ln(Z) was below 21, the dynamic recrystallization grain size increased rapidly. This critical ln(Z) value is a new finding. Strategies for controlling grain size in the production of ultra-large steam turbine rotors and heavy gas turbine disk forgings were provided. Finally, future research directions were discussed. Full article

The bolted rotor system functions as a critical component in aero-engines and gas turbines. Additionally, the misalignment fault is a typical and common fault in bolted rotor systems. Nevertheless, current research on bolted rotor systems has not covered misalignment faults. Therefore, a mathematical model of bolted rotor systems incorporating misalignment faults is established in this work. The nonlinear dynamics of bolted rotor systems involving misalignment are investigated by the comparison of the frequency amplitude responses, waterfall diagrams, rotor orbits and time-varying stiffness. Moreover, an in-depth analysis is conducted on the variations in vibration behaviors of rotor systems under different misalignment degrees. Finally, the proposed model is examined using rotor-rig tests conducted under aligned and misaligned conditions. A consistent observation from the numerical and test results is that the 2× frequency resonance speed does not equate precisely to 0.5 times the critical speed. In addition, the 2× component undergoes a sudden change as the misalignment level rises. Full article

This paper presents an intelligent cascaded fractional-order proportional–integral (CFO-PI) control strategy optimized using a genetic algorithm (GA) for a 1.5 MW DFIG-based multi-rotor wind turbine (MRWT) system. The primary objective is to enhance operational performance and power quality. The proposed method is evaluated against the conventional direct power control scheme using a traditional PI regulator (DPC-PI) to demonstrate its effectiveness. Comparative analysis shows substantial performance improvements achieved by the CFO-PI approach. Specifically, active power ripple is reduced by 61.71% compared to DPC-PI, resulting in smoother power delivery and improved grid compatibility. In addition, the steady-state error of active power decreases by 72.60%, indicating improved tracking accuracy. For reactive power, a 52.03% reduction in ripple is observed, while current ripple is reduced by approximately 56%, reflecting enhanced waveform quality. These results highlight the CFO-PI controller’s capability to maintain better power quality and steady-state performance relative to conventional DPC-PI. Overall, the GA-optimized CFO-PI controller provides a promising alternative for improving dynamic performance and power quality in DFIG-based MRWT systems. Full article

Hydraulic dynamometer is the key equipment to measure the dynamic performance of high-power gas turbines and steam, with its internal flow characteristics directly influencing measurement accuracy and service life. This paper focuses on the power absorption performance and internal flow characteristics of a hydraulic dynamometer with perforated-disk rotor. A hydraulic test platform is established to measure the power absorption performance of megawatt-level hydraulic dynamometers. When the rotor speed reaches a certain value under the full-water condition, the power absorption of the hydraulic dynamometer reaches its limit. Numerical simulations are applied to study the internal flow characteristics and cavitation evolution features of the perforated-disk-type hydraulic dynamometer. The flow within the outermost rotor pores is the primary factor influencing unsteady flow behaviour, with dynamic–static interference playing a key role in inducing flow excitation. Moreover, cavitation mainly occurs in the flow passages of the end rotor and the outermost flow pores of the middle rotor, where the development and collapse of cavitation bubbles lead to flow instability. As the rotation speed decreases, the power absorption performance significantly decreases under cavitation conditions. These findings provide a theoretical basis for the structural optimization and engineering application of high-power hydraulic dynamometers. Full article

This study investigates mechanism-based modeling and simulation of a single-shaft heavy-duty industrial gas turbine. Taking the PG9171E gas turbine as the case study, component-level steady-state and dynamic models are developed. The steady-state model is established using the constant mass flow (CMF) method. For dynamic modeling, both the CMF approach and the inter-component volume (ICV) approach are implemented to enable a comparative assessment of the two methods. On the basis of the steady-state model, an improved Dung Beetle Optimization (DBO) algorithm is proposed to perform model correction using measured operational data from the gas turbine. After model correction, the maximum relative error between the simulated results and the measured operating data is reduced to 1.01 × 10⁻⁵%. Following high-accuracy model correction, sensitivity analysis and a comparative dynamic study are conducted for the two dynamic modeling approaches. The results indicate that the most influential sensitivity parameter is the rotor rotational inertia, followed by the virtual volume of the combustor. Moreover, the primary discrepancy between the ICV and CMF approaches arises from differences in the operating trajectories on component characteristic maps. The ICV-based model exhibits a pronounced response lag; however, it requires less computational time than the CMF-based model, making it more suitable for rapid engineering simulation and practical applications. Full article

High-bypass ratio engines are currently among the most investigated solutions to achieve efficiency benefits and noise reduction in gas turbine engines. When equipped with a gearbox, these engines enable an optimized operation of the fan and of the low-pressure core, resulting in reduced weight and fuel consumption. The higher spool speed allows higher pressure ratios per stage, and consequently a reduced stage count. However, all this contributes to an enhanced sensitivity of the engine components to the development of secondary flow structures and separations, with a consequent impact on the aerodynamic performance and stability. In this context, an experimental campaign was conducted at the von Karman Institute for Fluid Dynamics on a highly loaded axial compressor representative of the first stage of a modern booster. The aim was to identify the flow features responsible of the performance loss at the operating points and speeds considered more critical in terms of rotor inlet incidence. To this end, time-averaged instrumentation was employed to characterize the performance and to retrieve the distribution of flow quantities at different axial positions within the stage, while fast-response probes allowed for the detailed characterization of the rotor outlet flow field. Unsteady 3D simulations complemented the experimental results and supported this interpretation, especially in regions with limited instrumentation access. The experimental and numerical results emphasized the role of the secondary flow structures developing near the hub wall as the main drivers for aerodynamic stall, due to the enhanced loading in this blade region. Full article

One of the most critical challenges in gas turbine design is preventing the ingestion of hot mainstream gases into the disk space between the stator and rotor disks. Rim seals and superposed sealant flows are commonly used to mitigate the risk of component overheating. However, leakage paths inevitably form between the mating interfaces of adjacent components due to the complex architecture of the engine. Therefore, the interaction between the different flows present within the disk space complicates the accurate determination of the optimal sealing flow quantity. For this reason, this study experimentally investigates fluid dynamics inside a stator–rotor cavity, with a particular focus on leakage flows. In particular, this work examines the impact of multiple parameters, including injection radius position, number of leakage holes, and injection angle, on the sealing effectiveness values measured on the stator side of the cavity through CO₂ gas sampling measurements. By comparing the effectiveness values with the swirl measurements derived from static and total pressure readings, the development of flow structures and the impact of leakage injection on sealing performance were finally evaluated. The results indicate that leakage injection has a minimal effect on the sealing effectiveness above the injection point, but significantly improves the performance at a lower radius. Moreover, it was observed that for a given mass flow rate, using a lower number of holes results in worse sealing performance due to a higher jet momentum, which causes the leakage flow to penetrate through the cavity toward the rotor side. In the end, employing two distinct injection angles—both aligned with the rotor’s direction of rotation—showed no substantial impact on sealing effectiveness. Full article

In the present work, off-design operating condition is considered to be the ability of the turbine to operate down to 50% to 20% of its nominal intake air flow rate. An important consequence of these off-design points is the change in the inlet incidence angle, which varied from nominal to −20°. Tests were performed on a seven-blade rotor cascade with platform cooling through an upstream slot simulating the stator-to-rotor interface gap. To model the impact of rotation on purge flow injection, a set of fins were installed inside the slot to give the coolant flow a tangential direction. Different cascades’ off-design operating conditions were tested, covering downstream velocity values up to Ma_2is = 0.55, with two inlet turbulence intensity levels of 0.6% a and 7%. A thermal measurement campaign was conducted with the Thermochromic Liquid Crystal technique to measure the adiabatic film cooling effectiveness at various coolant-to-main-flow mass flow ratios, different incidence angles, mainstream Mach numbers, and turbulence levels. The results describe the complexity of the turbine operating under off-design operating conditions, relating the improvement in the platform thermal protection to the reduced secondary-flows activity induced by negative incidence. Full article

This paper proposes a comprehensive framework, Theory–Simulation–Experimental Verification, for the elasto-aerodynamic analysis of elastic foil gas bearings (EFGBs). In contrast to many studies that approximate the foil structure using simplified two-dimensional models, the present work adopts a macro-element beam theory model that incorporates the actual 3D geometry, nonlinear elasticity, and frictional contact effects, and couples it directly with the Reynolds equation. To improve accuracy and robustness, the macro-beam results are validated against a fully coupled fluid–structure interaction (FSI) model developed in COMSOL Multiphysics. Emphasis is placed on quantifying the influence of foil thickness, clearance, and eccentricity, where the pressure distribution, foil deflection, and load capacity are obtained through the coupled solver. The results reveal that increasing foil thickness from 0.1 mm to 0.2 mm elevates the peak gas film pressure from 1.36 × 10⁵ Pa to 1.97 × 10⁵ Pa while simultaneously reducing displacement and pressure fluctuations, thereby enhancing bearing stability. Smaller clearances are shown to increase load capacity but also induce stronger oscillatory flow behavior, indicating a stiffness–stability trade-off. Additionally, prototype experiments with a 0.05 mm clearance confirm practical lift-off at 4300–7000 rpm under 10–30 N external loads, with measured torques of 0.18–0.30 N·m. By combining computational efficiency, 3D fidelity, and experimental validation, the proposed framework provides quantitative guidance for the design and optimization of EFGBs used in high-speed turbomachinery, such as aviation and compact energy systems, including turbine-based air-cycle refrigeration units and small gas-turbine rotors for unmanned aerial vehicles. Full article

Exposure of propulsion gas turbines to inlet flow contaminated with dust, sand, or ash particulates can lead to a myriad of complex and interrelated damage modes that reduce engine operational life, increase maintenance costs, and pose a safety risk to passengers and hardware assets. Experimental and computational research is ongoing to better understand the fundamental physics underlying this phenomenon, but data from full-scale engine tests with particles are needed for anchoring and validation under fully representative conditions. In this study, compressor blade/particle interactions are investigated at field-relevant conditions using Rolls-Royce/Allison M250-C20C turboshaft engines in an instrumented engine test cell. A novel experimental dataset was produced, yielding a qualitative visualization of particle impact regions on blades and vanes of an on-engine full six-stage axial compressor at transonic tip speeds for two particle compositions and two inlet particle delivery configurations. This investigation contributes the first experimental dataset of its kind for a rotating frame at transonic blade tip speeds (nominal Mach 1.0). By comparing the resulting impact patterns produced in this work to those of fielded hardware, it is shown that for field-relevant high-Stokes number particle conditions at the first-stage rotor, particle/engine dynamics simplify significantly due to ballistic inertial particle behavior. In addition, the spatial distribution of particle concentration and particle velocities across the compressor inlet plane was found to have only minor effects on the resulting particle/blade impact patterns for the two dust injection configurations tested. Full article

This paper proposes a novel methodology based on two intelligent algorithms for regulating the power output of a multi-rotor turbine system. A proportional-integral plus second-order integral regulator is utilized to regulate the energy output of an induction generator. The designed controller is characterized by its ease of configuration, cost-effectiveness, high robustness, and ease of implementation. The controller’s parameters are tuned using a genetic algorithm (GA) and a rooted tree optimization (RTO) algorithm, with the objective of maximizing operational performance and power quality. In accordance with the proposed design methodology, the optimal values for the parameters of the designed strategy are attained through the implementation of integral time-weighted absolute error (ITAE). The present controller has been designed to deviate from conventional controllers, and a comparison will be made between the two using MATLAB under various operating conditions. The operational performance was evaluated in comparison to the conventional algorithm in terms of current quality, torque ripples, threshold overshoot, system parameter changes, and so forth. The experimental results, as measured by the tests conducted, demonstrated that the proposed RTO-based regulator exhibited enhancements of up to 89.88% (traditional control) and 51.92% (GA) in active power ripples, 68.19% (compared to traditional control) in ITAE, 51.91% (traditional control) in reactive power overshoot, and 0.5% (compared to GA) in active power response time. Conversely, the proposed GA-based regulator yielded a steady-state error value that was 96.55% superior to the traditional approach and 86.48% more accurate than the RTO algorithm. Moreover, the efficacy of the RTO-based control system was found to be considerably augmented under variable system parameters. Total harmonic distortion improvements of 69% were observed compared to traditional control methods, and 1% compared to the GA technique. The findings of this study offer significant insights into enhancing the robustness of multi-rotor turbine systems and improving power quality. Full article

The paper presents a comprehensive evaluation of certain main parameters and the performance of microjet series models from the same engine manufacturer, AMT Netherlands, under various operating regimes. The study was performed through a percentage-based analysis of a series of actual values extracted from a set of charts, from which a specific database was created. The database comprised data sourced from official specification sheets issued by the manufacturer. The studied engines shared the same technical turbomachinery design, comprising a single shaft, one centrifugal compressor rotor, one axial turbine rotor stage, and a convergent jet nozzle, but differed in thrust class, ranging from 167 to 1569 N. Parameter and performance ratios were calculated to analyze the variation patterns within each engine and across different engines. The study refers to the variation analysis of thrust, fuel flow, exhaust gas temperature, and specific fuel consumption relative to engine speed, from idle to maximum regime. It presents the actual percentage values alongside polynomial functions that characterize the variations in engine parameters through which the analysis can be conducted. Full article