Simulation of abradable coatings compositions through microstructure image modeling

Performance deterioration in gas turbine engines (GTEs) depends on various factors in the ambient and the operating conditions. For example, humidity condensation at the inlet duct of a GTE creates water mist, which affects the fouling phenomena in the compressor and varies the performance. In this paper, the effective factors on the short-term performance deterioration of a GTE are identified and studied. GTE performance level is quantified with two physics-based performance indicators, calculated from the recorded operating data from the control system of a GTE over a full time between overhaul (TBO) period. A regularized particle filtering (RPF) framework is developed for filtering the indicator signals, and an adaptive neuro-fuzzy inference system (ANFIS) is then trained with the filtered signals and the effective ambient and the operating conditions, i.e., the power, the air mass flow, and the humidity condensation rate. The trained ANFIS model is then run to simulate the GTE performance deterioration in different conditions for system identification. The extracted behavior of the system clearly shows the dependency of the trend of performance deterioration on the operating conditions, especially the humidity condensation rate. The developed technique and the results can be utilized for GTE performance prediction, as well as for suggesting the optimum humidity supply at the GTE intake to control the performance deterioration rate.

This paper points out that the turbine performance computation method used widely at present in solving the performance of gas turbine engines is a numerically instable algorithm. So a new method, namely inverse algorithm, is proposed. This paper then further proposes a new mathematical model of solving the stable performance of gas turbine engines. It has the features of not only being suitable for inverse algorithm for turbine performance, but also having less dimensions than existing models. So it has the advantages of high accuracy, rapid convergence, good stability, less computations, and so forth. It has been fully proven that the accuracy of the new model is much greater than that of the common model for gas turbine engines. Additionally, the time consumed for solving the new model is approximately 1 / 4 ∼ 1 / 10 of that for the common model. Therefore, it is valuable in practice.

Safe operation of Gas Turbine Engines (GTEs) is one of the paramount missions in the GTE industry. Ensuring reliable operation and control performance is a challenging task that involves optimizing engine performance across various operating points. The Model Predictive Control (MPC) technique is a powerful approach that provides an optimization framework to meet the management and control requirements of GTEs during their operation. This work presents a systematic control framework to efficiently control a GTE. The proposed control algorithm employs an adaptive MPC methodology that ensures both safe and efficient engine operation. The MPC structure is adapted across varying operating points, and its parameters are optimized to provide control inputs that ensure best engine performance during both transient and steadystate engine operation. To enhance control reliability, the MPC is systematically coupled with min-max limiters to maintain critical variables within allowable bounds, ultimately to prevent engine surge, flame-out, and exceeding unsafe variable limits. Through this approach, the aim is to achieve a superior level of safety and operability for GTE control and management. Simulation results on a generic commercial turbofan engine with a 40,000-pound thrust show that the proposed algorithm outperforms a gain-scheduled PI controller with min-max limiters, and demonstrate enhanced performance in engine management and control.

Purpose The purpose of this study is to predict the performance and emission characteristics of micro gas turbine engines powered by alternate fuels. The micro gas turbine engine performance, combustion and emission characteristics are analyzed for the jet fuel with different additives. Design/methodology/approach The experimental investigation was carried out with Jet A-1 fuel on the gas turbine engines at different load conditions. The primary blends of the Jet A-1 fuels are from canola and solid waste pyrolysis oil. Then the ultrasonication of highly concentrated multiwall carbon nanotubes is carried with the primary blends of canola (Jet-A fuel 70%, canola 20% and 10% ethanol) and P20E (Jet-A 70% fuel, 20% PO and 10% ethanol). Findings The consumption of the fuel is appreciable with the blends at a very high static thrust. The 39% reduction in thrust specific fuel consumption associated with a 32% enhance in static thrust with P20E blend among different fuel blends. Moreover, due to the increase in ethanol concentration in the blends PO20E and C20E lead to a 22% rise in thermal efficiency and a 9% increase in higher oxygen content is observed. Practical implications The gas turbine engine emits very low emission of gases such as CO, CO2 and NOx by using the fuel blends, which typically reduces the fossil fuel usage limits with reduced pollutants. Originality/value The emission of the gas turbine engines is further optimized with the addition of hydrogen in Jet-A fuel. That is leading to high specific fuel exergy and owing to the lower carbon content in the hydrogen fuel when compared with that of the fossil fuels used in gas turbine engines. Therefore, the usage of hydrogen with nanofluids was so promising based on the results obtained for replacing fossil fuels.

Foreign object damage (FOD) is a common problem in gas turbine engines, particularly in the fan and compressor blades. FOD generally occurs when hard body particles are ingested into an aero-engine fan and compressor blade. High-speed impact on fan titanium alloy blades leads to foreign object damage, which weakens the fatigue performance of the blades. It is important to note that FOD can also cause damage that is not visible to the naked eye, such as internal cracks or fatigue damage. Therefore, regular inspections and maintenance are crucial to detect and prevent FOD damage in gas turbine engines. Also using a microscope for the inspection of blades is important. Proper examination of blades damaged by foreign or domestic object can shed light on blade status and prevent further damage in the future. Here are some of the benefits of using a microscope for blade inspection: Microscopes can provide high magnification and resolution, allowing for detailed inspection of the blade surface and any defects or damage. Microscopes can help detect and identify small cracks, chips, or other forms of damage that may not be visible to the naked eye. Microscopes can provide accurate measurements of the blade's dimensions, which can be important for quality control and maintenance purposes. Microscopes can help identify the root cause of any damage or wear on the blade, which can inform future design and manufacturing decisions. Microscopes can provide visual documentation of the blade's condition, which can be useful for tracking changes over time and for communicating with other stakeholders. Overall, using a microscope for blade inspection can help ensure the safety, reliability, and performance of gas turbine engines and other equipment that relies on blades. In this study, a comparison was made between visual inspection, borescope control, stereo microscope and SEM-EDX microscope methods used in the detection and removal of foreign material damage. The advantages and disadvantages of these 4 methods are comparatively examined and presented to the attention of the reader.

Bleed valves are widely used in gas turbine engines (GTEs) for airflow control to prevent compressor surge so as to improve the overall GTE performance and handling. Bleed valve fault detection is a challenging task due to the inhospitable environment that the bleed valve is located and the limited available sensor signals that can be used for detection. The problem is investigated in this paper and a Kalman filtering-based likelihood ratio approach is proposed for bleed valve event detection where only the pressure line signal and the scheduled bleed valve demand signals that are currently available in a GTE are used for detection. With the proposed approach, two models are developed for tracking the change in pressure signal, one with the scheduled bleed valve demand signals as input and one without. Two Kalman filters are designed based on these two models and the likelihood functions of the pressure observations are then evaluated with the state estimates from these Kalman filters. The bleed event detection is eventually achieved via the likelihood ratio test. The developed method is used for detecting bleed events using real flight data and the results are very promising.

Performance assessment of classical and fractional controllers for transient operation of gas turbine engines

Thermoacoustic instabilities have plagued the operation of gas turbine engines for years and significant research is being conducted in detecting and understanding them. In this paper, an output only identification technique is employed for a noise induced dynamical system representing combustion dynamics. Background turbulent flow in a combustor has a significant influence on combustion dynamics. In general, this flow noise is referred to as background noise, whose characteristics are unknown apriori. Identification of combustion dynamics with output only identification becomes challenging since the system dynamics and background noise dynamics are indistinguishable. To simplify the problem and identify both deterministic and stochastic components, a two-step identification using state space modelling is implemented. The data is transformed to accommodate an observer, which predicts the current state of a system from its previous states. The observer takes the form of a Kalman filter and in solving for the Kalman filter gain would solve the original problem yielding all the system matrices of the state space model. This approach is called the Output only Observer Kalman filter identification (O3KID) and its first step solves for least squares from a set of algebraic equations constructed from just the measured output. The least squares solution gives the Markov parameters (impulse response) and the output residuals. The subsequent step takes the Markov parameters or the residuals to solve for the system matrices using any deterministic sub-space identification method. In this paper, classical methods such as the Eigenvalue Realization Algorithm (ERA) using the Markov parameters is employed to solve for the system matrices. In using this direct non-iterative two-step algorithm, it is possible to estimate the eigenmodes and damping coefficients from output measured data. To validate the algorithm, a system of independent harmonic oscillators, excited by random noise is used to generate surrogate data representing pressure oscillations in a combustor prior to an instability. The O3KID algorithm could identify the eigenmodes with exactly the degrees of freedom required to define it i.e., a system with three harmonic oscillators could be defined with a 6-order model, which implies 6 coefficients. The same method was applied to pressure fluctuations data from a laboratory burner. The estimation of the most energetic modes was accurate with as few as 10 modes. This fast direct approach could be used to provide an early warning indicator in industrial gas turbines by tracking the rate of damping of dominant eigenmodes. Additionally, saving the state space parameters periodically can serve as a data-lean option to track changes of the dynamics and across a gas turbine fleet.

During the operation of gas turbine engines (GTE), failures are encountered due to structural, production, and operational defects. According to the damage of the gas turbine engine, the percentage of malfunctions in the lubrication and venting system is 2.9% [1]. This paper discusses the most common problematic issues in the operation of oil systems (OS) associated with the formation of solid decomposition products of oils on the surfaces of gas turbine engine parts. Laboratory studies of the creation of high-temperature carbon deposits on a heated aluminum surface were carried out by spraying the test oil on it for a specific time on the tilt plate instrument. This instrument was used to study NYCO TURBONIKOIL 98 aviation oil for aviation gas turbine engines (GTD-350, TV2-117, TV3-117, VK-2500) and main gearboxes (VR-2, VR-8A, VR-14, VR- 252) aircraft (Mi-2, Mi-8T, Mi-8MTV/AMT, Ka-32). Quantitative dependencies of the formation of carbon deposits on the oil temperature and the temperature of the aluminum plate are obtained, and a color template of the intensity of formation of solid high-temperature carbon deposits depending on the oil temperature and the temperature of the aluminum plate is presented.

This paper presents and evaluates a lost thrust method for analysis of thermodynamic performance in gas turbine engines. This method is based on the definition of a hypothetical ideal engine that is used as a point of comparison to evaluate performance of the real engine. Specifically, component loss is quantified in terms of decrements in thrust of the real engine relative to the ideal engine having the same design point cycle. These lost thrust decrements provide a basis for accurately evaluating the performance cost of component losses while simultaneously accounting for all component interactions. The analysis algorithm is formally developed in detail and is then demonstrated for a typical separate flow turbofan engine. Various scenarios are examined and the results of these exercises are used to draw conclusions regarding the strengths and weaknesses of this approach to gas turbine performance analysis.

A common method of optimizing coolant performance in gas turbine engines is through the use of shaped film-cooling holes. Despite widespread use of shaped holes, existing correlations for predicting performance are limited to narrow ranges of parameters. This study extends the prediction capability for shaped holes through the development of a physics-based empirical correlation for predicting laterally-averaged film-cooling effectiveness on a flat plate downstream of a row of shaped film-cooling holes. Existing data was used to determine the physical relationship between film-cooling effectiveness and several parameters, including; blowing ratio, hole coverage ratio, area ratio, and hole spacing. Those relationships were then incorporated into the skeleton form of an empirical correlation, using results from the literature to determine coefficients for the correlation. Predictions from the current correlation, as well as existing shaped hole correlations and a cylindrical hole correlation were compared to the existing experimental data. Results show that the current physics-based correlation yields a significant improvement in predictive capability, by expanding the valid parameter range and improving agreement with experimental data. Particularly significant is the inclusion of higher blowing ratio conditions (up to M = 2.5) into the current correlation, whereas the existing correlations worked adequately only at lower blowing ratios (M ≈ 0.5).

<div class="htmlview paragraph">Something exciting has been happening during these last several years. Structural components of a major engineering device were first constructed so that each one consisted of an individual metal crystal. These were alloy single crystal turbine blades for advanced aircraft jet engines. A new precision-casting technique, based on directional solidification, which imparts significantly improved ductility and thermal shock resistance to high-temperature, creep-resistant, nickel-base superalloys, has been carried through from research to production. This controlled solidification technique has been used to produce both columnar grain and alloy single crystal gas turbine components.</div> <div class="htmlview paragraph">The improvement in physical properties is achieved by controlling the solidification process to produce either columnar grains throughout a cast-to-size part, or a complete single crystal throughout a cast-to-size part, with a preferred [001] crystallographic orientation. This orientation is established parallel to the major stress axis of the part without the use of separate “seeding.” These parts have exhibited superior structural strength and stability in the severe operating environments associated with gas turbine engine operation. A comparison is made between the properties of superalloys having conventional equiaxed grains, directionally solidified columnar grains and [001] oriented single crystals.</div> <div class="htmlview paragraph">The evolution of this new process is traced from its beginning in columnar grain directional solidification experiments through the pilot-plant operation. The feasibility of producing parts using the “directional solidification process” has been demonstrated in production foundry facilities where several thousand gas turbine blades and vanes have been cast-to-size in various complex shapes.</div>

Investigation of particle size and amount of alumina on microstructure and mechanical properties of Al matrix composite made by powder metallurgy

To compare the thermal efficiency for an industrial gas turbine engine with that for the air-standard cycle. To introduce the open-cycle with friction for an industrial gas turbine engine. To compare the performance of the cycle with friction with the air-standard cycle. To discuss the operation of a two-shaft industrial gas turbine engine. To introduce the different types of aircraft gas turbine engines: turboprop turbojet turbofan To define the performance parameters for propulsive devices: thrust propulsive efficiency To compare the operating characteristics of aircraft gas turbine engines. To introduce the ideal cycle for a turbojet engine. To discuss the analysis and application of ram jet engines.

Blade-to-blade modeling of turbomachinery, based on methods for developing the parameters and characteristics of modern gas turbine engines, enables the resolution of a wide range of theoretically and practically significant problems in engine design, development, and operation. It also improves the accuracy of performance calculations. This article investigates thermogasdynamic processes within the flow part of a gas turbine engine and its elements, focusing in particular on a multi-stage gas turbine. The study is based on a method for developing the parameters and operational characteristics of a gas turbine engine, with a key component being a module for the final development of parameters of a multi-stage cooled gas turbine within the engine system. The object of investigation is a high-temperature cooled, multi-stage axial gas turbine for aircraft engines. The main result of this work is the development of a method for incremental sizing of parameters for a cooled, multi-stage turbine, along with a corresponding software package. This method was tested based on real development results. The investigation examined the parameters of the turbine stage blade row and the operating mode associated with rotor speed, showing the influx of impingement on the blade, observed only under specific rotor configurations at the QCD stage. The scientific and practical novelty of this work lies in its comprehensive approach to modeling the operation of a turboshaft gas turbine engine, providing a complete description of the compressor and turbine. This modeling is not feasible without a real-time simulation of thermogas-dynamic phenomena in the flow part of a multi-stage gas turbine, particularly in a single-stage plant behind the middle radius with the arrangement of cooling methods and the place of supply depending on the cooling system, as well as the temperature and losses, the emergence of critical operating modes when the blade screws twisting, which significantly influence turbine performance. The process is described using strict conservation laws for highly compressed gases, under conditions that ensure realistic flow power, consistent with values reported in the literature. The utility of the developed method, implemented in a dedicated software complex, will be connected to the complex of programs for the development of the characteristics of the gas turbine engine.