Gas Turbine Performance Research Articles

A Deterministic Calibration Method for the Thermodynamic Model of Gas Turbines

Performance adaptation is an effective way to improve the accuracy of gas turbine performance models. Although current performance adaptation methods, such as those using genetic algorithms or evolutionary computation to modify component characteristic maps, are useful for finding good solutions, they are essentially searching methods and suffer from long computation time. This paper presents a novel approach that can achieve good performance adaptation with low time complexity and without using any searching method. In this method, the actual component performance parameters are first estimated using engine measurements at different operating conditions. For each operating condition, some scaling factors are introduced and calculated to indicate the difference between the actual and predicted component performance parameters. Afterward, an interpolating algorithm is adopted to synthesize the scaling factors for modifying all major component maps. The adapted component maps are then able to make the engine model match all the gas path measurements and achieve the required accuracy of the engine performance model. The proposed approach has been tested with a model high-bypass turbofan engine using simulated data. The results show that the proposed performance adaptation approach can effectively improve the model’s accuracy. Specifically, the prediction errors can be reduced from about 9% to about 0.6%. In addition, this approach has much less computational complexity compared to other optimization-based counterparts.

Experimental Analysis of the Time-Wise Compressor Fouling Phenomenon

Abstract Compressor fouling is still an unforeseen phenomenon. Gas turbines for heavy-duty and propulsion applications are subject to performance degradation due to fouling, erosion, and corrosion mechanisms. Unlike the last two, the fouling phenomenon is recoverable depending on weather, operating conditions, and operator actions. It is generated by the adhesion of micro-sized particles on the relevant surfaces, generating blade shape and surface roughness variations. Fouling could affect the machine performance differently. The interaction between machine characteristics, airborne contaminants, and environmental conditions determines fouling prediction challenges. An experimental campaign has been carried out in the present analysis to study the overtime modification of compressor performance and mass deposits on the blade and vane surfaces. The axial unit has been operated to control the performance and deposition process by keeping the contamination and the relative humidity constant during the time. The test matrix has been based on two relative humidity values and four exposure time intervals. The results have shown the action of the competitive phenomena as adhesion and detachment, generating a non-linear trend of the deposited mass−time relation depending on impact characteristics and humidity values. Compressor performance follows similar behavior and shows a non-linear trend instead of constant contamination. Data interpretation and generalization are reported to increase the possibility of better predicting the effects of particle adhesion on gas turbine performance degradation.

Experimental study on the performance of micro gas turbines under different intake environments

This article uses experimental methods to measure the operational performance and pollutant emissions of micro gas turbines in different intake environments, and analyzes the feasibility of replacing mine ventilation fans with micro gas turbines. The results show that when the compressor efficiency is increased from 70 % to 90 %, the total efficiency of the micro combustion engine is increased from 28% to 34 %, with an increase of up to 21.4 %. When the demand power is 25 kW, the fluctuation range of NOx emission concentration is within 5.4 %. When the intake opening is below 50 %, the effect is obvious. When the intake opening is reduced from 50 % to 25 %, the performance of the micro gas turbine decreases by 0.7 %; The influence of intake humidity on various operating parameters of micro gas turbines is generally within 3 %, which can meet the requirements of high humidity environment operation; The intake temperature has the greatest impact, with an increase in intake temperature leading to a decrease in power generation efficiency. After comprehensive analysis, we believe that the application of gas turbines in mines is feasible.

Assessing the impact of CH[formula omitted]/H[formula omitted] blends on the thermodynamic performance of aero-derivative gas turbine CHP configurations

To attain a net zero-carbon emissions energy system, the grid needs dispatchable and flexible power production capable of responding to wind and solar energy variability. Hydrogen-fired gas turbines could play a role in meeting this requirement in the electricity grid; however, research and development are needed to assess the impact of the fuel change on these systems. This study aims to determine the effect of fuel switching on the cycle performance of a typical aero-derivative gas turbine, ranging from 25-35MW when combined with various steam-based bottoming cycles using Aspen Plus thermodynamic simulations. The gas turbine cycle’s efficiency and net output power increased by about 2.26% and 5.24%, respectively, when fueled with hydrogen for the constant TIT control strategy compared with the base case. The other two control strategies—constant TOT and heat input—are also positive. The performance of the combined heat and power configurations, expressed by the fuel charged to power, is better for almost all the hydrogen-fired cases compared with the methane case. This implies that using hydrogen as fuel in the gas turbine and duct-firing requires less fuel to produce heat and electricity. Although hydrogen integration into the overall system may pose challenges with auxiliary equipment, storage, supply, and combustion, hydrogen as fuel shows promise in improving the performance of gas turbine combined heat and power units.

Techno-Economic and Environmental Analysis of a Hybrid Power System Formed From Solid Oxide Fuel Cell, Gas Turbine, and Organic Rankine Cycle

Abstract Distributed energy technology is an essential pathway for future advancements in the field of energy technology. In the present study, organic Rankine cycle (ORC) is integrated with solid oxide fuel cell (SOFC)-gas turbine (GT) hybrid power system. The conventional metrics employed for assessing the performance of SOFCs, gas turbines, and organic Rankine cycles, such as voltage and gross real efficiencies, have some limitations as indices of merit. Contemporary second law concepts and economic and environmental analysis have been used to enhance hybrid power system evaluation. R1233zd(E) has been selected as the ORC working fluid. The outcomes reveal that, under certain conditions, the present configuration may reach 55.67% energy efficiency and 53.55% exergy efficiency. Economic and environmental analysis shows that the hybrid system's total cost rate and Emissions of CO2 gas (EMI) under design conditions are 36.09 $/h and 355.8 kg/MWh, respectively. Thermodynamic evaluation of present SOFC-GT-ORC configuration shows 11.72% improvement in exergy efficiency compared to hybrid SOFC-GT cycle. Consequently, the hybrid SOFC-GT-ORC system is far better than the hybrid SOFC-GT system. In the future, other ORC fluids like R123, R601a, and R245fa can be used as ORC fluids.

Cooperative economic dispatch of EV-HV coupled electric-hydrogen integrated energy system considering V2G response and carbon trading

With the increasing penetration of renewable energy, the Power-to-hydrogen technology accelerates the adoption of new energy vehicles, including both hydrogen vehicles (HV) and electric vehicles (EV). Simultaneously, the integration of Vehicle-to-Grid (V2G) technology further promotes the development of electric-hydrogen integrated energy systems coupled with transportation systems. In this study, an optimal scheduling model is developed for an EV-HV coupled electric-hydrogen integrated energy system, taking into account V2G response and carbon trading. Firstly, to address the randomness of renewable energy and loads, the Latin hypercube sampling method in conjunction with the Kantorovich scenario reduction method, is employed for scenario generation and simplification. Secondly, an optimization model is developed for the operation of hydrogen-blended gas turbines and the energy management of EVs and HVs. To encourage the participation of EVs and HVs, a reward mechanism for V2G responses is introduced, complemented by a time-of-use tariff, to guide orderly charging and discharging. Furthermore, the influence of the operating modes of EVs and HVs, as well as the hydrogen blending ratio, on the total system cost and carbon emissions is examined. An industrial park is selected as an illustrative example to showcase the effectiveness of the proposed method, demonstrating satisfied economic and environmental performances.

Modeling combined-cycle power plants in a detailed electricity market model

The efficiency and flexibility of combined-cycle gas turbines (CCGT) are gaining importance in view of more decarbonized energy systems. Therefore, an adequate representation of CCGTs in large-scale energy system models is required. When modeling large-scale energy systems, a trade-off between detailed representation of the technical restrictions and reasonable computing times emerges because of limited computing capacities.We present an approach that accounts for the operational dependencies between the gas and steam turbines of a CCGT but remains applicable in large-scale market models. Duct burners and bypasses that enable the solo operation of steam or gas turbines are also modeled. We implement our approach using the well-established Joint Market Model and apply it in a case study of the German electricity system in 2040.Our modeling approach captures more detailed operation modes, while increases in computation time remain limited. Thus, the approach is advantageous when turbine-wise modeling and analysis of CCGTs is required, e.g. for a detailed analysis of start-ups and operations. The results show no substantial differences between the aggregated market results of five cases investigated. The consideration of bypasses and duct burners yet leads to higher contribution margins for individual CCGTs – with stronger effects observed for more efficient groups.

Abating CO2 and non-CO2 emissions with hydrogen propulsion

Abstract This contribution focuses on the abatement with hydrogen of CO2 and non-CO2 emissions. It is agenda-setting in two respects. Firstly, it challenges the globally accepted hydrocarbon sustainable aviation fuel (SAF) pathway to sustainability and recommends that our industry accelerates along the hydrogen pathway to ‘green’ aviation. Secondly, it reports a philosophical and analytical investigation of appropriate accuracy on abatement strategies for nitrogen oxides and contrails of large hydrogen airliners. For the second contribution, a comparison is made of nitrogen oxide emissions and contrail avoidance options of two hydrogen airliners and a conventional airliner of similar passenger capacity. The hydrogen aircraft are representative of the first and second innovation waves where the main difference is the weight of the hydrogen tanks. Flights of 1000, 2000, 4000 and 8000 nautical miles are explored. Cranfield’s state of the art simulators for propulsion system integration and gas turbine performance (Orion and Turbomatch) were used for this. There are two primary contributions to knowledge. The first is a new set of questions to be asked of SAF and hydrogen decarbonising features. The second is the quantification of the benefits from hydrogen on non-CO2 emissions. For the second generation of long-range hydrogen-fuelled aircraft having gas turbine propulsion, lighter tanks (needing less thrust and lower gas temperatures) are anticipated to reduce NOx emissions by over 20%; in the case of contrails, the preliminary findings indicate that regardless of the fuel, contrails could largely be avoided with fuel-burn penalties of a few per cent. Mitigating action is only needed for a small fraction of flights. For conventional aircraft this penalty results in more CO2, while for hydrogen aircraft the additional emission is water vapour. The conclusion is that our research community should continue to consider hydrogen as the key ‘greening’ option for aviation, notwithstanding the very significant costs of transition.

A novel pathway for achieving efficient integration of SOFC/SOEC and addressing photovoltaic duck curve challenge

This study presents a novel method that directly integrates SOFC oxy-fuel combustion and SOEC co-electrolysis to tackle the challenges of high-energy consumption of SOFC/SOEC integration and photovoltaic duck curve. To explore the viability of this method, a biomass-solar complementary scenario is pioneered and its performance is assessed from thermodynamic and economic standpoints. The results show that the studied scenario achieves CHP and exergy efficiencies of 50.67% and 43.68% with the corresponding total product cost rate (Ċtot) of 45.44 $/h and the levelized cost of products (cp) of 14.61 $/GJ under the design conditions. The system annually produces 17485 tons of freshwater and 1432 tons of oxygen. Exergy analysis identifies the afterburner (AB-II) and supercritical CO2 recompression power cycle (SCRPC) as the primary contributors to exergy destruction with 381.74 kW and 343.62 kW, which alone account for over half of the total irreversibility. Increasing the isentropic efficiency of gas turbine (ηGT) and SOFC operating pressure (Pop) improves the overall thermodynamic performance, but enhancing SOFC current density and gasification temperature has adverse effects. Across varying Pop andηGT, there exist optimal Ċtot (44.83 $/h) and cp (14.47 $/GJ), which are obtained at ηGT of 80% and Pop of 600 kPa, as well as at ηGT of 87.14% and Pop of 800 kPa, respectively. This research can provide a reference for the development of cyclic energy storage technologies and the low-carbon transition in the energy fields.

Tracing the carbon capture energy distribution in a natural gas combined cycle power plant under variable operating conditions

A thermodynamic analysis method with a new criterion was introduced to reveal and dynamic track the internal energy consumption distribution of natural gas combined cycle power plants with CO2 capture. The new method decomposes the capture energy consumption into separation energy consumption and system integration energy consumption caused by gas turbines, steam turbines, heat recovery steam generators and steam extraction. The results indicate that load variation has little effect on the energy penalty of the separation process, which accounts for over 50 % of the total capture energy consumption and is stable at around 0.8 MJe/kg CO2 for MEA-based cases, while the integration performance becomes better with load decreasing, since the superior matching between extraction steam and reboiler parameters. Besides, exhaust gas recirculation technology reduces energy consumption caused by steam extraction by around 67 %∼85 % and brings an additional penalty of 0.1–6 MW on the gas turbine under 40–100 % load conditions. Therefore, exploring new absorbents and optimizing the matching between extraction steam and reboiler parameters are the critical points for capture system without exhaust gas recirculation. In contrast, for capture system with exhaust gas recirculation, energy consumption caused by the deterioration performance of gas turbines is crucial under high operation load, while absorbent innovation is dominant at low load. With the aid of the thermodynamic analysis method introduced in this paper, a better understanding of CO2 capture systems under variable load conditions can be obtained, which may be helpful for reducing energy consumption in CO2 capture technologies.

A digital twin approach for gas turbine performance based on deep multi-model fusion

Engine model plays a crucial role in various applications of energy system, such as health management and control optimization. However, the traditional physics-based model is challenging to address the engine-to-model mismatch while the data-driven model has difficulty in obtaining high-quality data. In this paper, a digital twin approach which innovatively integrates the machine learning, performance adaptation and component matching method is proposed to fuse physical mechanisms and big data. The bidirectional data flow between data-driven model and physics-based model is established through deep multi-model fusion. The data-driven model is constructed based on extreme learning machine for mapping adaptation factors. Whereby the physics-based model receives information to fine-tune its components. Meanwhile, the results of component matching are employed as a stable data source for predicting of data-driven model. Particularly, the parameters training the data-driven model are selected in a physics-based way based on the first-order approximation of engine. Compared with traditional adaptive method and hybrid method, the proposed approach can improve the simulation accuracy by 16.6 % and 9.9 %, respectively. The results indicate that the developed digital twin model can be used as an effective and reliable tool to predict gas turbine performance and contribute to decision-making.

Practical bifurcation analysis for the vibration’s proficiency and their influences on gas turbine operations: Towards the digitization of their monitoring

Practical bifurcation analysis for the vibration’s proficiency and their influences on gas turbine operations: Towards the digitization of their monitoring

Computational Study on Compressor-Combustor Interactions for Improved Matching of a Micro Gas Turbine

ABSTRACT Understanding complex aerodynamics/combustion interactions across major components of aeroengines, including the compressor, combustor and turbine is demanded for the improved performance of advanced propulsion systems. This study employs high-fidelity CFD simulations to investigate the coupled compressor-combustor interactions for the improved performance of a micro gas turbine. In the prototype configuration, the deficient compressor/combustor matching causes insufficient air/fuel mixing and delayed combustion inside the combustor chamber. By reducing the flow area of the compressor and redistributing the air holes on the combustor chamber, a stable united recirculation structure is formed to promote air/fuel mixing and efficient combustion, achieving a over 50% decrease in OTDF and RTDF at the combustor exit and a total 20% decrease of pressure loss in the entire engine through-flow. Compared with the single-component combustor simulation, the coupled compressor-combustor results exhibit stronger turbulence mixing, increased temperature uniformity inside the combustor chamber. Compared with the single-component compressor simulation, the compressor in the multi-component simulation shows the reduced flow angle and Mach number at the compressor outlet, leading to increased stall critical angles and delayed flow separation at the compressor diffuser and vanes. This demonstrates that the added combustor endues the compressor with an expanded operating range and a lower mass-flow rate instability boundary. This work implies that 3D multi-component CFD simulation is necessary to understand the aerodynamic and combustion interactions and improve the multi-component matching in gas turbine engines.

Robustness optimization of gas turbine performance evaluation against sensor failures

Robustness optimization of gas turbine performance evaluation against sensor failures

Pyrolysis-derived waste polypropylene oils in gas turbine engines: a comprehensive performance and emission study

Addressing the burgeoning issue of polymer waste management and disposal, chemical recycling, specifically the production of highquality oil, presents an enticing solution. This research paper delves into the process of plastic waste pyrolysis, focusing on polypropylene, and thoroughly examines the physico-chemical properties of the resulting pyrolytic oil. The oils, obtained from waste plastic pyrolysis (referred to as WPPO), are then blended with kerosene and utilized as fuel for a gas turbine engine. The primary objective of this investigation is to ascertain how the blend composition influences the performance and emission parameters of the micro gas turbine. In our findings, it was observed that all tested waste plastic pyrolysis blends displayed a trend towards escalating regulated emissions such as nitrogen oxides (NOx) with an average increase of 26% for polypropylene pyrolysis oil (PPO). The emission index (EI) for carbon monoxide (CO) was found to be relatively consistent across all fuel blends tested in this study. Interestingly, when considering the thrust specific fuel consumption (TSFC) within the EI calculation, blends of aviation kerosene and plastic oil showed lower values in comparison to the pure Jet A-1 fuel. Furthermore, an augmentation in the proportion of WPPO in the blends consequently led to an elevation in the exhaust gas temperature (an average increase of 8.7% for PPO). Interestingly, the fuel efficiency of the Jet engine, expressed as TSFC, demonstrated a decrease, with an average reduction of 13.8% observed for PPO.

A Novel Data-Driven Approach for Predicting the Performance Degradation of a Gas Turbine

Gas turbines operate under harsh conditions of high temperature and pressure for extended periods, inevitably experiencing performance degradation. Predicting the performance degradation trend of gas turbines and optimizing planned maintenance cycles are crucial for the economic and safety aspects of gas turbine operation. In this study, a novel data-driven approach for predicting gas turbine performance degradation is proposed. Initially, gas turbine operating data are augmented using a mechanism model. Subsequently, a data-driven performance model is constructed based on support vector regression (SVR) and gas turbine operational characteristics, enabling real-time calculation of performance degradation indicators. Building on this, an Autoregressive Neural Network (AR-Net) is employed to construct a model for predicting the trend of performance degradation. The proposed method is applied to predict performance degradation caused by fouling in the compressor of a gas turbine. Comparative analysis with three other performance degradation prediction methods indicates that the proposed approach accurately identifies the performance degradation trend of gas turbines, determining the optimal maintenance timing. This holds significant importance for the condition-based maintenance of gas turbines.

Effect of regenerative effectiveness on the performance of simple gas turbine

The deregulation of the power and energy sector introduced a strong element of competition. Power plant operators try to develop techniques to maximize profits in the dynamic power industry. New methods of improving and optimizing simple gas turbine power plants are needed to enhance operational decision making and therefore to maximize power plant profitability by reducing operational and maintenance cost and increasing revenue. In this work, the thermodynamic model equations of both a simple gas turbine and regenerative gas turbine cycle were used to analyses the effect of increase in the regenerative effectiveness to the performance of the simple gas turbine. Microsoft Excel 2010 software was used to carried out the analysis. It was observed that for the simple gas turbine the thermal efficiency, heat rate, specific fuel consumption and heat addition have a constant value of 35.4%, 9630Btu/Kwh, 0.2768kg/Kwh, 44237.8Kw, all through, while for the regenerative gas turbine cycle as the value of the regenerative effectiveness increases from 0.8 to 1.0, the thermal efficiency increases from 41.1% to 65.0%, the heat rate decreases from 8753Btu/Kwh to 5536 Btu/Kwh , specific fuel consumption decreases from 0.248945122Kg/Kw.h to 0.157432413 Kg/Kw.h and heat addition reduces from 39782.5Kw to 25158.4Kw. It was seen clearly that the regenerative gas turbine cycle has higher thermal efficiency compare to the simple gas turbine, and as the regenerative effectiveness of the regenerative gas turbine cycle increases the performance of the regenerative gas turbine increases.

Analysis of the influence of hydrogen co-firing on the operation and performance of the gas turbine and combined cycle

The effect of hydrogen co-firing on the performance and operating conditions of gas turbines (GTs) and gas turbine combined cycles (GTCCs) was investigated. Two operating scenarios were applied, and off-design analyses were conducted for three GTs with different turbine inlet temperatures (TITs). In the first scenario, the TIT was kept constant. As the hydrogen co-firing ratio increases, the pressure ratio of GT increased, and the power outputs of both GT and GTCC increased. With 100 % hydrogen in the 1650 °C GT, power output and efficiency improved by 5.36 % and 1.55 %p for GT, and 2.90 % and 0.72 %p for GTCC. In the second scenario, the power output was kept constant. The operating point moves toward lower pressure ratio and TIT regimes, and the efficiency of both GT and GTCC increased. With 100 % hydrogen in the 1650 °C GT, TIT decreased by 50.3K, and efficiency increased by 1.42 %p for GT, and 24.9K and 0.42 %p for GTCC. In both scenarios, the higher the TIT, the impact of hydrogen co-firing was more pronounced. It is expected that the second scenario might reduce NOx emissions while still increasing system efficiency in comparison to the NG fired case by operating the GT at a lower TIT and equivalence ratio.

Effects of Water-to-Air Mass Ratio on Long-Term Washing Efficiency and Erosion Risk in an Axial Compressor Under Online Washing Conditions

Abstract One of the main reasons for gas turbines’ performance losses is the deposition of dirt on the compressor blades. Dirt deposit has to be periodically removed to keep the engine performance as high as possible. This is the reason motivating the presence of online water washing systems in most compressor gas turbines. Such systems aim at cleaning the compressor blades to recover efficiency; thus, the larger the water flow, the better it is assumed the compressor is cleaned (fixing all the other conditions). In the present work, we simulate the long-term behavior of a real axial compressor, from the inlet to the first-stage rotor, subject to online water washing with different water flowrates. The frozen rotor approach is adopted to solve the flow field in the rotor region. Simulations are performed by using the unsteady k-ɛ realizable model coupled with a Lagrangian tracking of the injected liquid phase. Water droplet erosion is handled by using a semi-empirical model developed by the authors. In each simulation, 504,000 parcels have been tracked, providing statistically reliable predictions. To simulate the long-term evolution of the washing process, a discrete mesh morphing technique coupled with the use of specific scale factors is adopted. Each of the tested configurations is composed of three successive erosive steps up to the blade compressor end-of-life. By varying the water-to-air mass fraction (WAMF*), six different injection configurations are assessed in terms of long-time average washing efficiency and erosion risk. The results predicted show the dependence of the considered washing indices on water mass flowrate and set the stage for the development of a washing optimization tool, which can help the design and management processes. In scenarios where washing indices are given minimal importance and the objective is to reduce the risk of erosion, the optimal injection configuration was shown to correspond to a WAMF* value of 0.250. Conversely, when washing efficiency is prioritized, the optimal injection configuration has been shown to correspond to the case where WAMF* = 0.750.

Study on characteristics and mechanism of re‐entrainment in intake filtration components of the gas turbine

AbstractAiming at the problem that the droplet re‐entrainment in the intake filtration components affects the gas intake quality and the safe operation of gas turbines, the characteristics and mechanism of the re‐entrainment in a marine double‐hook inertial stage filter are studied, and the distribution of liquid film and re‐entrainment under different inlet air velocities and droplet size distributions are compared. The results show that, due to the influence of inertia and turbulent dispersion, droplets tend to deposit on draining hooks and the lower surface of the leeward side of the blade to form a liquid film. Film stripping is the main form of re‐entrainment under ship‐driving conditions. Due to the high airflow velocity and the large film thickness, hook peaks are the most prone to film stripping, and the critical airflow for film stripping velocity is 14.8 m/s. With the increase of the inlet air velocity, the film thickness at the draining hooks increased first and then decreased, and the film stripping positions were extended from the hook peaks to the rear. Different droplet size distributions mainly affect the liquid film thickness at the draining hook and leeward side of the blade, which in turn affects the film stripping mass.