Gas Turbine Research Articles

EFFICIENCY OF USE CHARACTERISTICS OF DAMPING OF TURBINE BLADES FOR CRACK DIAGNOSTICS

During operation, turbine blades are subjected to intense mechanical (static and dynamic) and thermal loads in a corrosive and aggressive environment. The consequence of such loading is the gradual accumulation of diffuse fatigue damage, which eventually becomes localized as a fatigue crack. When the crack reaches a critical size, there is a danger of blade destruction with catastrophic consequences for the entire turbine. Timely detection of blade damage is possible at the stage of turbine repair using vibration diagnostics. The purpose of the work is to create an analytical approach that allows modeling the change in the vibration damping characteristics of a turbine blade with a fatigue crack, as well as the study of the influence of the crack parameters and the geometric parameters of the blade on the vibration damping characteristics of the blade to assess the effectiveness of vibration diagnostics of damage. The results of the study of the effect of a surface transverse crack on the damping characteristics of turbine blade oscillations are presented. As a result of the experimental and analytical study, the effect of the crack parameters (size and location of the crack) and the geometric parameters of the blade on the damping characteristics of blade vibrations was established. Vibration diagnostic of turbine blades, based on a change in the damping characteristics of its vibrations, is a sufficiently effective diagnostic feature for detecting relatively small cracks, the size of which does not pose a threat to the integrity of the blades. Given that the materials used for the manufacture of modern steam turbines and gas turbine engines have a rather low damping capacity, the use of changes in the damping characteristics of blade oscillations as a vibration diagnostic sign of damage is promising. Further work involves the study of the effect of cracks that appear on the edges of the blades on the damping characteristics of blade vibrations

Transient Thermal Mapping Utilizing the Sintering of Glass‐Ceramics

Thermal paints are essential for mapping the surface temperature of gas turbine engine components but can only indicate maximum temperature. A novel transient thermal history sensor that combines the capabilities of a thermocouple with those of a thermal paint is developed here, enabling the retrieval of full thermal history using a “sintering” model. The glassy ceramic thermal paint undergoes a qualitative optical transition due to sintering in response to temperature that is quantified using UV–vis spectroscopy. This provides high‐resolution transient temperature measurement (±6 °C) when maximum temperature is above its glass transition temperature (Tg) of 563 °C and up to 660 °C. The glass‐ceramic coating exhibits strong adhesion to Inconel 718 substrates due to matched coefficients of thermal expansion. By fabricating similar paints with distinct temperature ranges and placing them in proximity, this approach can significantly reduce the number of thermocouples needed for surface temperature mapping, thereby improving the accuracy of measurements required for engine validation.

Dirt Ingestion Impacts on Cooling within a Double-Walled Combustor Liner

Abstract Double-walled liners consisting of impingement and effusion cooling are commonly used to cool gas turbine combustor chambers. Engine ingestion of particulate such as dirt, sand, or ash leads to particulate deposition and blockage of cooling holes in these liners. Prior work on double-walled liners has shown that deposition leads to flow blockage, however, no experimental work has studied the reductions in cooling that result from the deposition. The goal for the present work was to quantify this reduction in cooling by evaluating the heat transfer coefficient on the cold-side of an effusion plate with and without dirt buildup. Heat transfer coefficients were quantified over a range of Reynolds numbers, pressure ratios, plate-to-plate spacings, and dirt injection amounts. The injection of dirt onto the cold-side effusion plate surface resulted in flow blockages and cooling reductions as high as 55%, with these effects differing for pressure ratio and plate-to-plate spacing. Scan data of the dirty effusion plate was used to characterize the deposition thicknesses for the different parameters tested. Overall, the heat transfer when having deposition on the effusion plate affected the cooling much beyond the insulation effect of the dirt layer. These results suggest that the effects of particulate buildup on the cooling flow field are an important driver in double-wall combustor liners.

Sistem Monitoring Dan Kontrol Berbasis Internet Of Things Pada Prototypesmart Portable Biomass Powerplant

The use of Internet of Things technology can be implemented in various aspects, one of which is the field of energy generation. The generation of electrical energy, especially biomass fuel, can be one way to achieve more environmentally friendly energy generation. Design prototype smart portable biomass powerplant includes monitoring and control of the generating system. The monitoring and control system is designed to be able to run automatically integrated with the Internet of Things system. To increase the ease of use of the tool, the system is connected in real-time with the internet. Data acquisition with sensors connected to the controller is carried out to observe the condition of the combustion chamber, turbine and generator components. The results of this data acquisition can then be monitored in real-time on a platform that can be done remotely. The control process on the prototype includes protection measures on the device in case of fault so as to provide further damage prevention measures and can be done wirelessly using the same system. Prototype testing results using Arduino mega2560 controller and ACS712 current sensor, voltage sensor, MQ-2 gas sensor and esp32 cam were found to be able to work well and monitor both the condition of the combustion chamber, the power generated by the generator to biomass combustion levels. Then the test also proved to be able to provide remote process control to protect the tool from overheating, overcurrent protection and excessive incomplete combustion process.

Influence of vortex generator dimensions on film cooling efficiency

Enhancements in gas turbine blade cooling techniques, such as film cooling, have significantly advanced the aerothermal effi-ciency of turbines, especially in transportation sectors like aeronautics and automotive industries. This study aims to enhance turbine blade cooling by incorporating an obstruction at the jet exit. The vortex generator angle has been modified to 25°, 45°, 60°, 90° and 110°. These five designs were assessed in comparison to the conventional cylindrical hole configurations. Two injection ratios (M = 0.25, and M = 0.5) were studied within the ANSYS CFX 16 software, utilizing the finite volume method to solve the average Reynolds equations and the energy equation. The findings show qualitative alignment with experimental data for the base scenario, indicating that the vortex generator angle notably amplifies film cooling effectiveness. Typically, the vortex generator configured at 90° exhibits a stronger mixing capability compared to the other cases and cylindrical design.

Review of The Impact Of Hydrogen-Containing Fuels On Gas Turbine Hot-Section Materials

Abstract In an effort to achieve worldwide decarbonization goals, a range of low-carbon fuels is being proposed for use in power-generation gas turbines. Two promising fuels are hydrogen and ammonia, which do not produce any CO2 upon combustion. While the use cases of these fuels differ, each has the potential to reduce the carbon intensity of power generation as compared to the current use of natural gas and fuel oil. Many studies have considered the impact that these fuels will have on combustion stability and emissions, as well as other practical considerations like balance of plant. However, potential challenges for the material systems in these engines, particularly high-temperature metal alloys and coatings, have not been sufficiently considered in preparation for the introduction of these fuels. The goal of this paper is to provide a review of the potential material issues associated with implementation of these hydrogen-containing fuels, with a focus on materials in the hot section of existing power-generation gas turbines. To date, relatively little research has considered these material issues at realistic gas turbine conditions, resulting in a need for new research. This paper provides a review of the literature, first-order analyses of the magnitude of potential issues, and avenues for research to facilitate the safe and reliable introduction of these fuels in power-generation gas turbines.

Effects of Lattice Orientation Angle On Tpms-Based Transpiration Cooling

Abstract Establishing a continuous cooling film is an effective way to thermally protect hot-gas path components of gas turbines. For aero-engines, effusion cooling is the state-of-the-art method for developing cooling films. However, the cooling film generated by this method is far from ideal, as discrete miniature cooling air jets exiting from effusion cooling holes leave large gaps between cooling holes without adequate cooling film protection. Furthermore, effusion cooling jets can experience strong lift-off from component surfaces and are subsequently diluted due to mixing with the main flow. Recent advances in additive manufacturing (AM) technologies have enabled the fabrication of porous materials with precisely engineered lattice structures, significantly enhancing the film cooling effectiveness of hot-gas path components through transpiration cooling. A prior study has demonstrated highly promising transpiration cooling results by using a family of lattice geometries referred to as triply periodic minimal surface (TPMS) lattices. The present study experimentally investigates the influence of various TPMS lattice orientations on the film cooling effectiveness. Three types of TPMS structures, namely Diamond, Koch and Gyroid, are compared to demonstrate that the TPMS lattice orientation angle affects transpiration cooling performance, with different levels of sensitivity according to the TPMS structure. The TPMS lattice structures studied in this investigation are fabricated by stereolithography (SLA) 3D printing. The adiabatic cooling film effectiveness (AFE) is measured using pressure sensitive paint (PSP).

Insights on the tribological characteristics of titanium alloys in demanding environments

Abstract Titanium alloys are widely used in demanding applications due to their exceptional strength-to-weight ratio, high-temperature resilience, and excellent corrosion resistance. Understanding their tribological behavior is critical, as the performance and durability of several mechanical systems, particularly in gas turbine engines, are often constrained by friction and wear in complex contacting and mobile assemblies. This study investigates the tribological behavior of two widely used titanium alloys, Ti-6-4 and Ti-6-2-4-2, focusing on their interfacial phenomena under varied operational conditions. Tribological testing was conducted using a reciprocating tribometer at different temperatures and loading conditions. Ex-situ analyses revealed that wear mechanisms were heavily influenced by the properties of the oxide layer formed during sliding. Under higher loads, the oxide layer on the alloy surface fractured, resulting in the generation of flake-like debris, which contributed to third-body abrasion. Additionally, the study examined the transfer film formation on the alumina counterface under various conditions, correlating friction and wear behavior with interfacial processes, particularly the oxide formation on the worn surfaces. This study enhances the understanding of the tribological behavior of titanium alloys, paving the way for improved performance in demanding applications through advanced surface modification techniques.

Development of a Methodology for Obtaining Solid Models of Products That Are Objects of Reverse Engineering Using the Example of the Capstone Micro-GTU C 65

Currently, about a thousand micro gas turbine units of small and medium capacity are in operation in the Russian Federation, which are used as an autonomous power source at critical infrastructure facilities. During long-term operation, the component parts of the micro GTU may fail and require replacement or repair. The lack of spare parts and design documentation for their production makes it impossible to operate. As a way to solve the problem, the reverse engineering process can be used to produce components. One of the stages of reverse engineering is to determine the geometric parameters of the object. The fastest and most accurate way to obtain geometric characteristics in the reverse engineering process is 3D scanning. Three-dimensional scanning technology is used to obtain a solid 3D model of the prototype surface, based on which design documentation is subsequently developed. This article presents the results of a study of the influence of the parameters of the distance between polygonal grid points and the scanner exposure on the detailing of the outer surface and the geometric parameters of the resulting polygonal model. As a result of this study, the dependence of the final file size and the time spent on scanning and processing on the distance between the points of the polygonal grid and the model was established. Based on the dependence of the parameters, recommendations were obtained for choosing the distance between the points of the polygonal grid of laser 3D scanning. Also, after performing the stages of reverse engineering, the methodology for creating solid models and design documentation of parts of power equipment units using 3D scanning technology was improved.

A Preliminary Economic Analysis of the Process of Decarbonising an Oil-Exporting Country: The Case of Libya

This paper offers a basic analysis for strategic decision-makers of the process when an economy shifts from oil to non-carbon energy exports and zero carbon emissions. The fundamental concept is how to offer environmental performance without causing an economic contraction. The costs and feasibility of solar, wind, and helium closed-cycle technologies are thoroughly and independently compared. Solar panels make up 0.67% of the USD 1.14 trillion total cost of solar energy, which is the capital investment, with panels accounting for 0.51%. Future technical developments are expected to bring down the cost of such solar farms to USD 0.74 trillion. Turbines comprise 66% of the estimated USD 0.67 trillion wind energy costs. At USD 0.36 trillion, helium closed-cycle gas turbines—which account for 0.78% of the overall cost—are essential for stabilising energy output. With a focus on cost viability, this analysis offers direction for Libya’s transition to energy self-sufficiency and export, in support of global carbon reduction targets. It also offers unique insights into areas not previously covered by other studies. This paper’s unique contribution is its economic analysis of the decarbonisation of an entire oil-exporting nation.

Optimization of Elaeis Guineensis Shell Ash Nanoparticles for Gas Turbine Blade Coating

The nanoparticles of elaeis guineensis (oil palm) kernel shell ash was developed into recipe for the fabrication of composite coatings on gas turbine blades, with electrodeposition technique employed. To prepare the electrodeposition bath; 100g/l ZnCl2, 5g/l Thiourea, 15g/l Boric acid, and 100g/l KCl were utilized and the recipe for the fabrication of the composite coatings were 0, 5, 10, 15, 20 and 25g/l of the nanoparticles. This paper tends to analyse the various percentage weight of the recipe making up the electrolyte, with a view to investigating and ascertaining the effectiveness of the coatings derived from each composition through; coating thickness, hardness value, surface roughness, X-ray Diffraction (XRD), electrical conductivity, tribology and microstructure analysis. Whereas the results of the investigation reveal that the performance of gas turbine blade was enhanced with the composite coatings, the 20g/l composition was found to be most effective. The decrease in the performance beyond this composition is attributable to the fact that the electrolyte became too viscous to promote easy flow of electrons during electrodeposition, as was similarly observed in previous work.

A Practical Approach to Modeling and Performance Analysis of a Turboshaft Engine Using Matlab

This article presents a detailed approach to constructing a numerical model of a free power turbine engine specifically designed for performance analysis in the Matlab R2024b environment. The core innovation of this model lies in its integration of precise engine geometry parameters, calculated at the design point, and performance characteristics of key components such as the compressor and power turbine. These components are modeled to reflect significant variations in their performance based on changing operational conditions, including rotor speed and environmental factors. To validate the model’s assumptions, data from the PZL-3W engine were used. The model was created by meticulously incorporating the engine’s specific design characteristics, allowing for an in-depth examination of how performance characteristics shift with adjustments to high-pressure rotor settings or changes in ambient conditions. The resulting calculations demonstrated a high level of agreement between the model’s output and empirical data available for the PZL-3W engine, as well as with data found in the relevant scientific literature. This alignment underscores the model’s robustness and reliability in simulating engine performance across a range of operating scenarios, making it a valuable tool for further engineering analyses and optimization of free power turbine engines and their possible application.

Full-cycle grids numerical simulation of the performance for newly developed micro turbine engine

Purpose The purpose of this research is to investigate the feasibility of using the components series connection (CSC) method to predict the performance of a newly developed micro turbine engine (MTE) under rated operating condition. Design/methodology/approach The main research object is the MTE with known factory performance parameters, and the finite element method is used to discretize its main components into a full-cycle grid and then simulate it in the computational fluid dynamics method under rated operating condition using the CSC method. Finally, compare the results obtained by numerical simulations with the factory design parameters of the MTE. Findings The performance and flow field of MTE and each component were simulated and obtained. Compared with the factory design parameters, the errors are acceptable, with the outlet average total temperature and thrust exhibiting errors of 1.4% and 7.6%, respectively. Practical implications This paper introduces a faster and more convenient method for simulating the performance of MTE components and the entire engine while also making the simulations more realistic. The method was used to analyze the performance of the components and the whole engine of a newly developed MTE. Originality/value This research validates the feasibility of evaluating the overall performance of the MTE using the CSC method and provides a new method to solve performance calculations for MTE under any known working conditions.

Levitation Performance of Radial Film Riding Seals for Gas Turbine Engines

Levitation Performance of Radial Film Riding Seals for Gas Turbine Engines

Data-driven approach for the classification of gas turbine faults

Gas turbines (GTs) play a crucial role in the production of electricity. Extreme working conditions can lead to deterioration in GTs' performance, resulting in the occurrence of various issues. This study proposes an approach to deal with this issue by combining a layered recurrent neural network (LRNN) with principal component analysis (PCA). This approach aims to reduce the dimensionality of data and computational complexity effectively while enhancing the accuracy of gas turbine fault classification. The methodology outlined consists of two steps. The first step is to apply PCA to the dataset that was collected from the gas turbine. By transforming the data into a lower-dimensional space, PCA helps to eliminate redundant information and improve computational efficiency. Next, LRNN is employed to detect and classify faults in the gas turbine. The LRNN’s structure enables it to capture complex patterns and relationships in the data, which enhances the accuracy of fault classification. This study is based on historical data collected from a gas turbine power station, consisting of 8200 samples of 34 measured variables. The operating parameters contain data such as temperature and pressure. Each data point's relationship to a specific turbine scenario reveals if it is healthy or one of the four faulty scenarios. The results showed that by combining the LRNN with PCA, the gas turbine fault classification achieved good performance in terms of accuracy, precision and neural network model performances, while also showcasing the faster convergence speed of the LRNN when trained on PCA instead of the original dataset.

Revealing the NO Formation Kinetics for NH3/CH4 Blends Under Dual-Flame and Premixed Swirl Flame Configurations

Ammonia stands out as a promising zero-carbon fuel and an efficient hydrogen carrier, offering great promise for industrial applications in gas turbines and boilers. However, different combustion modes significantly influence the flame structure and combustion characteristics of ammonia. In this study, two distinct fuel injection strategies were employed in a model combustor: ammonia and methane, under fully premixed and dual-flame combustion modes. Numerical simulations were performed to analyze the flame structure, velocity fields, and temperature distribution, complemented by planar flow field, flame OH* chemiluminescence, and NO emission measurements. Findings reveal that with an increasing NH3 ratio, the flame front becomes more elongated with more pronounced temperature fluctuations at the swirler exit. Particularly, at 50% NH3, a significant reduction in flame temperature is observed, notably at a height of 30 mm from the burner. For dual flames, the reaction NH2 + O ↔ HNO + H was less significant compared to its effect in premixed flames, whereas the H + O2 ↔ O + OH reaction demonstrated the highest sensitivity coefficient. An increase in the NH3 ratio correspondingly led to a reduction in NO consumption reaction rates, heightening the sensitivity coefficient for NO inhibition, and providing critical insights into ammonia combustion optimization.

Life cycle assessment and thermodynamic performance of biomass-based combined cogeneration

Abstract This study presents a thermodynamic and life cycle analysis of a biomass-based integrated energy system, comprising a biomass gasification cycle, a steam Rankine cycle, and an ammonia fluid Organic Rankine cycle. The primary objective of the system is to efficiently convert olive husk, a sustainable biomass source, into electricity and heating. The gasification process generates syngas, which fuels a gas turbine, producing high-temperature exhaust that drives a Rankine cycle. The thermodynamic analysis indicates that the overall system achieves an energy efficiency of 20.85% and an exergy efficiency of 11.70%. The Rankine cycle exhibits an energy efficiency of 23.91%, while the Organic Rankine cycle demonstrates a higher exergy efficiency of 68.87%. Parametric studies reveal that increasing the combustion chamber temperature significantly enhances system efficiency and output, with energy efficiency rising linearly as the temperature increases from 800 °C to 1000 °C. Additionally, the analysis emphasizes the importance of the compressor's compression ratio on system performance. A life cycle assessment conducted using the ReCiPe methodology evaluates the environmental impact of the system throughout its lifecycle, revealing critical insights into its sustainability. This comprehensive evaluation highlights the potential of utilizing agricultural waste, such as olive husk, to produce renewable energy, thereby supporting environmental sustainability and waste management goals. The findings underscore the viability of the proposed system for enhancing energy production while minimizing environmental impacts, making it a promising solution for renewable energy generation in regions with abundant biomass resources.

In-Hole Measurements of Flow Inside Fan-Shaped Film Cooling Holes and Downstream Effects

The study of low-speed jets into crossflow is critical to the performance of gas turbines. Film cooling is a method to maintain manageable blade temperatures in turbine sections while increasing turbine inlet temperatures and turbine efficiencies. Initially, cooling holes were cylindrical. Film cooling jets from these discrete round holes were found to be very susceptible to jet liftoff, which reduces surface effectiveness. Shaped holes have become prominent for improved coolant coverage. Fan-shaped holes are the most common design and have shown good improvement over round holes. However, fan-shaped holes introduce additional parameters to the already complex task of modeling cooling effectiveness. Studies of these flows range in hole lengths from those found in actual turbine blades to very long holes with fully developed flow. The flow within the holes themselves is difficult to study as there is limited optical access. However, the flow within the holes has a strong effect on the resulting properties of the jet. This study presents velocity and vorticity fields measured using high-resolution magnetic resonance velocimetry (MRV) to study three different fan-shaped hole geometries at two blowing ratios. Because MRV does not require line of sight, it provides otherwise hard-to-obtain experimental data of the flow within the film cooling hole in addition to the mainflow measurements. By allowing measurement within the cooling hole, MRV shows how a poor choice of diffuser start point and angle can be detrimental to film cooling if overall hole length and cooling flow velocity are not properly accounted for in the design. The downstream effect of these choices on the jet height and counter-rotating vortex pair is also observed.

The energy management strategy of two-by-one combined cycle gas turbine based on dynamic programming

The complexity and nonlinearity of components in large-scale thermal facilities have resulted in a lack of recognized energy management models, and simple rule-based energy management strategies are still the main approach, which reduces their operating efficiency. In this study, a dynamic programming (DP) method for globally optimal power distribution and operation mode decision for two-by-one combined cycle gas turbine is proposed. First, the energy management model of system is established. Then the drum pressure of the heat recovery steam generator, which indicates the thermal energy storage of the system, is chosen as the state variable, while the control variables are the gas turbine power, turbine power and operation mode. In addition, the system response time is considered to re-evaluated the mode switch command. The simulation results show that the DP optimizes the thermal storage management, which allows the gas turbine to run in the high-efficiency operating range for a longer time. The DP-based strategy saves 6.25%, 5.89%, and 4.92% of fuel at initial drum pressure 8MPa, 9MPa, and 10MPa, respectively, compared to the rule-based strategy. The results of this study can be used as a benchmark to evaluate online energy management strategies in future work.

Regional and seasonal impact of hydrogen propulsion systems on potential contrail cirrus cover

The decarbonization of air transportation requires novel propulsion concepts in order to replace fossil kerosene powered gas turbines. Within various options, H2 based propulsion is one of the most promising candidates, at least for regional and short haul routes. However, despite the potential to reduce CO2 emissions to zero, those aircraft can still have a significant climate impact due to increased contrail formation caused by higher water emission when using H2 as a propellant. In order to understand potential changes in the climate impact of H2 powered air traffic, it is crucial to evaluate how the potential for contrail formation and the potential contrail cirrus cover would change under representative atmospheric conditions. To this end, we developed a tool which uses several years of meteorological reanalysis data (ERA-5 and MERRA-2) in combination with contrail formation conditions adjusted to H2 gas turbine and H2 Fuel Cell propulsion in order to investigate their regional and seasonal variation. Contrail formation conditions for three different propulsion settings (kerosene gas turbine, H2 gas turbine and H2 fuel cell) are calculated to obtain global statistics of potential contrail cover and potential contrail cirrus cover over 12 years. For H2 based propulsion contrails are more likely to form due to the increased water vapor emission. However, this does not necessarily translate into the climatically relevant potential for contrail cirrus formation. Focusing on three hot spots of regional air traffic, we find that the difference between kerosene and H2 scenarios has a strong systematic dependency on season, altitude and latitude. Maximum differences in potential contrail cirrus cover are found in the transition region from typically no-contrail to contrail forming conditions at a potential contrail cover around 50%. In contrast, less to no difference in potential contrail cirrus cover is found at very high (close to 100%) or rather low potential contrail cover. This study demonstrates, that the question whether H2 powered air traffic produces more climate relevant contrail cirrus can not be parameterized by a simple factor but rather strongly depends on the propulsion type, season, region and flight altitude.