Gas Turbine Research Articles

Comprehensive approach to static firing tests of micro gas turbine engines powered by liquid fuels

Comprehensive approach to static firing tests of micro gas turbine engines powered by liquid fuels

Effect of swirler geometry on the outlet temperature profile performance of a model gas turbine combustor

Effect of swirler geometry on the outlet temperature profile performance of a model gas turbine combustor

Comprehensive thermodynamic, environmental, and economic analyses of a modified waste heat recovery process for a gas turbine cycle producing power, cooling, and hydrogen

Comprehensive thermodynamic, environmental, and economic analyses of a modified waste heat recovery process for a gas turbine cycle producing power, cooling, and hydrogen

Effect of rear blunt body structure and inlet conditions on the flow and combustion characteristics of an advanced vortex combustor for a gas turbine

Effect of rear blunt body structure and inlet conditions on the flow and combustion characteristics of an advanced vortex combustor for a gas turbine

Study on Shutter Heating Performance of Gas Turbine Intake System

Abstract Aiming at the anti-icing and de-icing requirements of gas turbine intake system, study the heating performance of a typical shutter vane, and compares and analyzes the influence of different ambient temperature and different electrothermal pipe heat generation rate on vane temperature distribution and heat transfer characteristics. The results show that the air convection at different positions on the blade surface of the louver leads to the difference in the temperature distribution of the upper and lower surfaces of the blade, as well as the leading edge and trailing edge of the blade, and the leading edge of the blade, as the area with the lowest overall temperature distribution of the blade, should be focused on in the design of anti-icing and de-icing systems. Increasing the heat production rate of the electric heating tube, there is more heat flow near the midline of the blade, which makes the temperature rise at this position the highest, and it is necessary to pay attention to the energy waste and blade damage caused by local overheating of the blade. Therefore, when the ambient temperature increases from 245.15 K to 318.15 K, the leaf temperature increases from 248.73 K to 322.74 K, and the temperature rise also increases from 3.58 K to 4.59 K. The electrothermal technology can be used to the anti-icing and de-icing of the intake system shutters on the basis of choosing the heat generation rate of the electrothermal tube reasonably.

Energetic and Exergoeconomic Evaluation of a Stig Cycle and Cooled Inlet Air Gas Turbine Powered by Mixtures of Natural Gas and H2 in Tropical Climates

Energetic and Exergoeconomic Evaluation of a Stig Cycle and Cooled Inlet Air Gas Turbine Powered by Mixtures of Natural Gas and H2 in Tropical Climates

Study of three-dimensional crack extension in turbine discs of short-life turbojet engines

Abstract A simulation study on the 3D crack extension of short-lived turbojet engine turbine discs was carried out using FRANC3D 3D fracture mechanics software combined with ABAQUS finite element software. By establishing a 3D geometric model of the turbine disc, the crack extension process is simulated by using the sub-model method, and the crack extension behavior and failure mode are analyzed to predict the remaining life of the cracked wheel disc. The results show that the crack expansion path matches well with the crack failure phenomenon of the turbine disc under the actual working conditions; the turbine disc crack is dominated by Type I (open Type) crack expansion, and the stress intensity factors of Type II and Type III are negligible; the crack expansion rate increases slowly with the increase of crack depth, and it rises steeply at the critical value of the fracture failure; and the residual life of the turbine disc is 32 cycles. This study provides empirical analyses for crack monitoring and life prediction of turbine discs and is of great significance for engine maintenance and reduction of end-of-life costs of turbine components.

Micro Gas Turbines in the Global Energy Landscape: Bridging the Techno-Economic Gap with Comparative and Adaptive Insights from Internal Combustion Engines and Renewable Energy Sources

This paper investigates the potential of Micro Gas Turbines (MGTs) in the global shift towards low-carbon energy systems, particularly focusing on their integration within microgrids and distributed energy generation systems. MGTs, recognized for their fuel flexibility and efficiency, have yet to achieve the commercialization success of rival technologies such as Internal Combustion Engines (ICEs), wind turbines, and solar power (PV) installations. Through a comprehensive review of recent techno-economic assessment (TEA) studies, we highlight the challenges and opportunities for MGTs, emphasizing the critical role of TEA in driving market penetration and technological advancement. Comparative analysis with ICE and RES technologies reveals significant gaps in TEA activities for MGTs, which have hindered their broader adoption. This paper also explores the learning and experience effects associated with TEA, demonstrating how increased research activities have propelled the success of ICE and RES technologies. The analysis reveals a broad range of learning and experience effects, with learning rates (α) varying from 0.1 to 0.25 and experience rates (β) from 0.05 to 0.15, highlighting the significant role these effects play in reducing the levelized cost of energy (LCOE) and improving the net present value (NPV) of MGT systems. Hybrid systems integrating MGTs with renewable energy sources (RESs) and ICE technologies demonstrate the most substantial cost reductions and efficiency improvements, with systems like the hybrid renewable energy CCHP with ICE achieving a learning rate of α = 0.25 and significant LCOE reductions from USD 0.02/kWh to USD 0.017/kWh. These findings emphasize the need for targeted TEA studies and strategic investments to unlock the full potential of MGTs in a decarbonized energy landscape. By leveraging learning and experience effects, stakeholders can predict cost trajectories more accurately and make informed investment decisions, positioning MGTs as a competitive and sustainable energy solution in the global energy transition.

Biomass-Based Gas Turbine Systems for Power Generation: Sustainable Feedstocks and Environmental Benefits

This paper explores the significance and operational mechanisms of biomass-based gas turbine systems, which present a renewable and sustainable substitute for conventional fossil fuel-based electricity production methods. These systems utilize biomass as a source of fuel to produce heat, which is then converted into power through a gas turbine. The process involves the combustion of biomass fuel to heat a working fluid, such as air, which subsequently drives the turbine to produce electricity. Biomass can be derived from various organic materials, encompassing urban solid trash, forest residues, and agricultural residues, making it a versatile and sustainable fuel option. The paper also includes a practical case study, highlighting the system's advantages and disadvantages. Additionally, it identifies future trends, emphasizing the importance of efficiency enhancement. To achieve this, scientists are increasingly proposing hybrid systems that combine biomass-based gas turbines with other technologies. This approach aims to optimize performance, reduce emissions, and contribute to guaranteeing a future with more sustainable energy. The study underscores the potential of biomass-based gas turbine systems to play a crucial part in the shift to renewable energy sources.

Innovative Design and Fast Iterative Manufacturing of Micro-Turbojet Engines at Low Cost

The turbojet is the foundation of the gas turbine engine, which combines knowledge of fluid dynamics, thermodynamics, heat transfer, mechanical design, manufacturing, and jet propulsion. This paper describes in detail the inspiration source, design process, fluid dynamics analysis, manufacturing steps, ignition test method and test process of small jet engines. 3D modeling software SolidWorks was used for the preliminary modeling and fluid simulation was performed to optimize the design. Part of the model was produced by 3D resin printing technology, and the turbine engine model was driven by compressed air for no-load testing to verify the feasibility and structural stability of the resin model. Subsequently, some parts were printed with metal materials, combined with traditional machining techniques to complete production and assembly, and finally successfully carried out static ignition tests. The micro turbojet engine designed in this paper has successfully achieved static ignition test and demonstrated the feasibility of efficient development with limited resources and low manufacturing cost. This exploration proves the feasibility of rapid iteration technology route. The market prospect and manufacturing cost of micro turbojet are also analyzed.

Predicting bifurcation and amplitude death characteristics of thermoacoustic instabilities from PINNs-derived van der Pol oscillators

Self-sustained thermoacoustic oscillations as observed in low-emission combustion- involved gas turbines and aero-engines involve complicated thermal fluid–acoustics interaction and rich nonlinear dynamics. Such pulsating oscillations are known as thermoacoustic instability. When it occurs, large-amplitude limit cycle oscillations (LCOs) of thermodynamic parameters are frequently observed. These LCOs could cause overheating, flame flashback, and even engine failures. Thus it is critical to understand and predict the generation mechanisms and nonlinear dynamics behaviours, and then develop corresponding control approaches to prevent or control the onset of such instabilities. In this work, we develop and extend the classical van der Pol oscillators by integrating a physics-informed neural networks (PINNs) algorithm with a modelled nonlinear Rijke-type thermoacoustic combustor. The theoretical Rijke tube system (with Galerkin expansion and modified King's law implemented) and a CFD simulation model are applied to provide ‘training/calibration data’ for the extended van der Pol (EVDP)-PINNs model. The optimized EVDP oscillators are confirmed to be capable of capturing the key nonlinear characteristics by comparing the transient growth behaviours of thermodynamic perturbations and LCO amplitude and frequency. Further investigations are conducted to obtain Hopf bifurcation and amplitude death (AD) characteristics. Comparison is then made to the coupled EVDP systems. Quite similar Hopf bifurcation features, but differences in regions of AD, are observed. In general, we demonstrate an applicable approach to intelligently ‘learn’ a nonlinear thermoacoustic system and to create reliable EVDP oscillator systems, which have great potential to contribute to the development and testing of control approaches, such as the coupling described in this work, which may replace costly experimental tests.

Diagnosis of GHG Emissions in an Offshore Oil and Gas Production Facility

This work presents a diagnosis of greenhouse gas (GHG) emissions for floating production storage and offloading (FPSO) platforms for oil and gas production offshore, using calculation methodologies from the American Petroleum Institute (API) and U.S. Environmental Protection Agency (EPA). To carry out this analysis, design data of an FPSO platform is used for the GHG emissions estimation, considering operations under steady conditions and oil and gas processing system simulations in the Aspen HYSYS® software. The main direct emission sources of GHG are identified, including the main combustion processes (gas turbines for electric generation and gas turbine-driven CO2 compressors), flaring and venting, as well as fugitive emissions. The study assesses a high CO2 content in molar composition of the associated gas, an important factor that is considered in estimating fugitive emissions during the processes of primary separation and main gas compression. The resulting information indicates that, on average, 95% of total emissions are produced by combustion sources. In the latest production stages of the oil and gas field, it consumes 2 times more energy and emits 2.3 times CO2 in terms of produced hydrocarbons. This diagnosis provides a baseline and starting point for the implementation of energy efficiency measures and/or carbon capture and storage (CCS) technologies on the FPSO in order to reduce CO2 and CH4 emissions, as well as identify the major sources of emissions in the production process.

Experimental and numerical investigations into cold flow characteristics of multiple micro-mixing jets for hydrogen-rich gas turbines

To explore the flow field of micro-mixing jets, cold flow characteristics of a model Micromix burner were investigated by particle image velocimetry (PIV) system and Large-eddy simulation (LES) model. Results show that LES results are in good agreement with experimental results. In the flow field of multiple micro-mixing jets, the jet velocities of nozzles farther away from the burner center have a high increase and decay rate. When the outlet Reynolds number increases, the Reynolds stress increases first and then decreases in the merging region indicating that the velocity fluctuation disappears in the second jet half, but it has little effect on the flow field structure. Comparing the flow fields of round multiple micro-mixing jets, the merging point and combined point in the elliptical jets flow field move backward. Moreover, the maximum velocity for elliptical jets is also faster than the round jets, which is caused by the high turbulent kinetic energy in the elliptical jet flow field. When the tube spacing increases from 2 to 3 times the tube diameter, positions of the two feature points change linearly. Further, the surrounding jets can decrease the velocity attenuation of the center nozzle and elongate the axial length of the two feature regions.

Adaptive robust self‐scheduling for a wind‐based GenCo equipped with power‐to‐gas system and gas turbine to participate in electricity and natural gas markets

AbstractIntegrating renewable energy, particularly wind generation, into power systems brings significant uncertainty and intermittency, challenging generation companies (GenCos) to maintain economic operations. This paper proposes a strategy for a wind‐based GenCo equipped with a gas turbine and a power‐to‐gas (PtG) system to balance wind variability. The gas turbine offsets power shortfalls by consuming natural gas, while the PtG system absorbs excess wind energy, converting it to natural gas and injecting it into the natural gas network as a form of storage. The GenCo operates in day‐ahead electricity and natural gas markets and the real‐time electricity market, addressing uncertainties from wind output, energy prices, and natural gas access. A tri‐level adaptive robust optimization model is introduced for the GenCo’s short‐term operational scheduling. At the first level, decisions related to the GenCo's participation in the day‐ahead electricity and natural gas markets are made. The second level deals with determining the worst‐case realization of the uncertainties, constrained by the budget of uncertainty and the limited range of variations of uncertain variables. The third level sets the operational strategy on the actual day, considering power and gas balance, as well as constraints for the wind farm, gas turbine, and PtG unit. A column & constraint generation (C&CG) algorithm is used to solve the model. Numerical results demonstrate the model’s effectiveness in various case studies, showing that the GenCo can manage wind uncertainties, benefit from arbitrage opportunities in electricity and gas markets, and improve economic outcomes. This approach supports the broader integration of renewable energy into power systems.

Improving fatigue life of a titanium alloy through coupled electromagnetic treatments

TC11 titanium alloy is widely used in the manufacture of key components such as blades of gas turbine and aero engine because of its high specific strength and good processing performance. In the case of gas turbine or aero engine, the fatigue performance of TC11 will directly determine the life of the turbine or engine, and the surface residual stress generated on the alloy during manufacturing often affects the fatigue life of the material. In this study, a new method of coupled electromagnetic treatment (CEMT) was applied to regulate the surface residual stress of the alloy after manufacturing, so as to improve the fatigue life of the TC11. The results show that after the CEMT, the residual compressive stress in the length direction and width direction increased by 63.7% and 56.0% respectively, the fatigue life of the TC11 is increased by 39.9%. The microstructure analysis shows that after CEMT, the width of fatigue striations is significantly reduced. This paper proposes that CEMT can be used as an effective method to adjust the residual stress of materials and improve the fatigue life of titanium alloys. The research is also relevant for improvement of the fatigue life of other alloy materials.

The Influence of Gas Fuel Enrichment with Hydrogen on the Combustion Characteristics of Combustors: A Review

Hydrogen is a promising fuel because it has good capabilities to operate gas turbines. Due to its ignition speed, which exceeds the ignition of traditional fuel, it achieves a higher thermal efficiency while the resulting emissions are low. So, it was used as a clean and sustainable energy source. This paper reviews the most important research that was concerned with studying the characteristics of hydrogen combustion within incinerators and power generation equipment, where hydrogen was used as a fuel mixed with traditional fuel in the combustion chambers of gas turbines. It also includes an evaluation of the combustion processes and flame formation resulting from the enrichment of gaseous fuels with hydrogen and partial oxidation. A large amount of theoretical and experimental work in this field has been reviewed. This review summarizes the predictive and experimental results of various research interests in the field of hydrogen combustion and also production.

Optimization of Tip Seal Grooves for Aerodynamic and Durability Improvements of Small-Core Turbines

Abstract While the gap between the turbine rotor tip and the outer case in a gas turbine engine is necessary for engine function, the gap is kept as small as possible due to the detrimental effect of the flow over the turbine tip. With the increased investments in ultra-high bypass turbofans, blade tip clearances are increasing in relative size to the turbine rotor, as engines move towards smaller cores. In this work, an optimization of a rotor tip seal with discrete axisymmetric grooves was explored computationally using RANS simulations. The optimization was applied at two tip clearances representing a nominal and small-core-scaled geometry, and with both flat- and squealer-tipped blades. The multi-objective optimization was designed to maximize rotor efficiency and minimize tip heat load. Several casing designs were identified for each tip configuration that both increased efficiency and reduced the heat load into the rotor tip. However, some optimal tip seal designs were composed of grooves that were demonstrated to be detrimental in prior work. Furthermore, grooves were more effective at increasing efficiency when applied to flat tipped geometries – increasing efficiency by 0.9 points over the ungrooved baseline with flat tipped blades, as opposed to 0.25 points over the ungrooved case with squealer tipped blades. Finally, optimal seal geometries that were obtained from the small-core scaled clearance gap optimizations maintained near optimal performance when evaluated at the design tip clearance, while those geometries developed at the design clearance experienced greater tip gap sensitivity.

Critical machining parameters for large aircraft casing production considering the influence of clamping systems

AbstractIn recent years, there has been a notable initiation or acceleration in the production of new aeronautical engines. This surge is coupled with a global commitment to reducing emissions and mitigating noise generated by gas turbines used in aeronautical applications. A critical component in this context is the aeronautical casing. The manufacturing process is intricate and time-consuming, compounded by the complexity of the clamping system, which poses a significant challenge to productivity. This study undertakes a comprehensive analysis of the critical variables essential for the optimal manufacturing of a zero-defects large-scale casing. The examination encompasses design criteria, raw materials, constraints related to clamping systems and tooling, and process monitoring. Ultimately, the exploration extends to the examination of more sustainable manufacturing techniques. To facilitate this, a case study involving the fabrication of a life-size aeronautical casing is undertaken.

Investigation of Structural Phase, Mechanical, and Tribological Characteristics of Layer Gradient Heat-Protective Coatings Obtained by the Detonation Spraying Method.

This paper presents the results of a study of layer gradient thermal protection coatings based on NiCrAlY and YSZ obtained by detonation spraying. Modern gas turbines and high-temperature units operate under extreme temperatures and aggressive environments, which requires effective protection of components from wear, corrosion, and thermal shocks. In this study, the use of layer gradient coatings consisting of alternating layers of NiCrAlY and YSZ was investigated with the aim of solving the problem of thermal stress accumulation due to a smooth change in the composition of the layers. Microstructural and phase analysis showed that alternating layers of NiCrAlY and YSZ formed a dense layer gradient structure with clear interphase boundaries and low porosity. Detonation spraying led to a complete transformation of the monoclinic ZrO2 phase into a tetragonal one, which significantly increased the mechanical strength of the coating and its resistance to thermal shocks. Sample 1D1 demonstrated excellent tribological and corrosion properties in a 3.5% NaCl solution, which can be explained by its higher density and reduced number of pores. Mechanical tests revealed stable values of hardness and wear resistance of the coating, especially for the 1D1 coating. Studies have shown that coatings are resistant to thermal shocks, but thicker layers show a tendency to peel off after thermal cycling. The obtained results indicate high prospects for the use of layer gradient coatings based on NiCrAlY and YSZ for the protection of gas turbine components and other high-temperature installations operating under extreme loads and aggressive environments.

Experimental Study on Liquid Jet Trajectory in Cross Flow of Swirling Air at Elevated Pressure Condition

Abstract Motivated by fuel atomization applications in gas turbine combustors, this paper presents an experimental examination of liquid jet trajectory and spray dynamics in crossflow of swirling air, at elevated pressure conditions. The study was conducted within an annular passage and was focused on momentum flux ratio and swirl number as the main parameters. The momentum flux ratio was varied from 2 to 25 through incremental adjustments to the liquid injection velocity and the swirl number values of 0.42 and 0.74 were used, representing typical gas turbine fuel atomization conditions. Jet trajectories were captured by imaging the three-dimensional helical path traced by the liquid jet using two mutually perpendicular optical windows. Radial penetration was quantified by solving the equations of a helix. The key findings revealed that radial penetration of the liquid jet is larger for higher momentum flux ratios and is influenced by the helical arc length. Notably, the radial penetration observed at low momentum flux ratios was larger for crossflow with lower swirl number and the radial penetration observed at high momentum flux ratios was more for crossflows with higher swirl number. In comparison to the spray characteristics in swirling crossflows at atmospheric pressure, condition of elevated gaseous pressure resulted in lower radial penetration, jet spread and jet area. Jet trajectory correlations for elevated pressure conditions are additionally presented, developed using curve fitting to the experimental data, which will be useful to the industry for estimation of spray trajectory in swirling crossflows at high pressure conditions.