Turbine Inlet Research Articles

Performance assessment of compressed air energy storage systems with and without phase change materials

In this study, two integrated hybrid solar energy-based systems with thermal energy storage options for power production are proposed, thermodynamically analyzed and comparatively evaluated. The first system uses an underground cavern to store compressed air energy. When electricity production is high during the day, a compressor set pressurizes the air and directs it to the storage unit. A heat transfer model is developed to determine temperature variations and heat losses through the cavern walls. During the insufficient solar radiation period, the compressed air inside the cavern is discharged to meet the energy needs. The second energy storage system employs a cascade latent heat storage approach to reduce heat dissipation within the cavern. The temperature of the compressed hot air gradually decreases as it passes through three-stage phase change material (PCM) units. The cascaded PCMs help reduce the temperature differences between the storage media and minimize the exergy destruction rates. Similar to the first energy storage option, the pressurized air is stored in an underground cavern. The compressed air is then discharged and passes through the latent heat storage medium in the energy recovery mode, eventually reaching the turbine inlet temperature. Finally, the high-pressure and high-temperature air drives the gas turbine and hence generator to generate electricity. The thermodynamic quantities, including energy and exergy efficiencies and exergy destruction rates, are determined for all system elements and comparatively assessed. Furthermore, a comprehensive evaluation of the thermodynamic performance criteria of these energy storage options is carried out.

Multi-aspect exergo-economic/environmental study/optimization of an eco-friendly heat integration process for gas turbine modular helium reactors in integration with a Stirling engine

As a nuclear power source, gas turbine modular helium reactors (GT-MHR) can play a major role in the energy industry due to their high safety index and low operating costs. In light of the GT-MHR's high heat capacity, this study integrates a GT-MHR cycle with a Stirling engine to achieve a high-efficiency electricity production framework in an eco-friendly framework. Multi-aspect study from energy, exergy, economic and exergoenvironmental viewpoints are conducted. Detailed heat exchanger modeling is performed to accurately evaluate the system's performance conditions as part of the design process. The outcomes of this study reveal that in the optimum operating mode, the turbine's inlet temperature and expansion ratio are 1300 K and 2, respectively. The compressor compression ratio is 2.1, the Stirling engine inlet temperature is 850.6 K, and the regenerative effectiveness is 0.866. Consequently, the system's total electricity becomes 325.57 MW with 54.26 % energetic and 75.13 % exergetic efficiencies. The economic assessment of the system reveals that the unit electricity product cost is 8.9 $/GJ, and the total investment cost is 12737 $/h. Also, the optimal exergoenvironmental results show an exergoenvironmental index of 0.237, an environmental damage effectiveness index of 0.0031, and an exergetic stability factor of 0.24. Compared to GT-MHR, GT-MHR/KC, GT-MHR/APC, and GT-MHR/ORC, the newly designed system produces 44.57, 21.47, 29.74, and 25.17 MW more electricity and is more energetically efficient by 28.3 %, 24.45 %, 25.8 %, and 25.07 %, respectively.

Study on flow and heat transfer characteristics in rectangular channels with lantern-shaped pin fin array: Part II—Global sensitivity analysis and optimization

Increasing gas turbine inlet temperatures are placing more stringent requirements on the efficiency of internal cooling. Pin fin arrays are a common tool for cooling electronic components or trailing edge cooling channels of gas turbine blades. A crucial concern for researchers is how to achieve a higher Nusselt number with constrained pressure loss to guarantee that the efficiency of the gas turbine will not be impacted by the power dissipation generated by the driving flow passing through the internal cooling loops. In Part I of this study, a lantern-shaped pin is proposed. To seek a more efficient design solution for the pin fin shape, the second part combines the surrogate model, Sobol’s method, and NSGA-II optimization method to perform the overall and spatial sensitivity analysis and optimization for the shape variables on the generatrix of different pin rows. The first-order and total-order sensitivity indices of different variables to Nu T and f are calculated using the surrogate model-based Sobol’s method. The variables that significantly affect the channel performance are identified. The overall and spatial sensitivity analysis results indicate that the variable X 3 i -1 contributes the most to Nu T and f, with total-order sensitivity indices of 70.59–64.26 and 58.16–59.09%, respectively. The overall optimization increases the Nu T and f by 6.95 and 9.91%, respectively, while the spatial optimization leads to an increase in the Nu T by 2.29% and a decrease in the f by 4.56%. Correspondingly, the two optimizations resulted in an increase in the TPI by 3.61 and 3.89%, respectively. The Pareto front solution obtained by the spatial optimization has a more concentrated distribution. Although the TPI obtained by the spatial optimization is only 0.21% higher than that of the overall optimization, it provides designers with a strategy considering the Nusselt number and pressure loss.

Optimum design of bivariate operation strategy for a supercritical/ transcritical CO2 hybrid waste heat recovery system driven by gas turbine exhaust

Gas turbines are always operated under part-load conditions to participate in the frequency regulation of power grids; therefore, the exhaust gas has fluctuating temperature and mass flow rate parameters. For better utilization of the waste heat in gas turbine exhaust under part-load conditions, a supercritical/transcritical carbon dioxide (CO2) hybrid waste heat recovery system with different operation strategies was studied. The turbine inlet pressure and mass flow rate were considered as the dominant factors affecting the system part-load performance, which formed a bivariate operation strategy. A solution procedure was proposed to optimize the bivariate operation strategy for a hybrid waste heat recovery system. The results indicate that the mass flow rate of the transcritical CO2 cycle has a greater effect on its net power than the turbine inlet pressure whereas these two regulation variables should be controlled cooperatively. The net power of the hybrid waste heat recovery system increased with an increase in the inlet valve opening of the supercritical CO2 turbine under a specific gas turbine load. Generally, the optimal bivariate operation strategy has the advantage of enhancing the part-load performance of a hybrid waste heat recovery system driven by gas turbine exhaust.

Exergy Audit of Thermodynamic Parameters and Performance Analysis of OgorodeThermal Power Plant in Delta State, Nigeria.

The exergy analysis of the Ogorode steam plant is presented. The aim was to determine and identify the magnitudes and locations of real exergy losses in order to improve plant efficiency. The exergy losses occurred in the various components of the steam plant, such as the boiler, economizer, turbine, super heater, condenser, pump, feed water heater, reheater, and air pre-heater, and these have been calculated using the concepts of availability or available exergy and irreversibility. The temperature and pressure of the plant's running conditions were combined to determine the process irreversibility (exergy losses) and the exergy efficiency of the plant. The exergy losses of the individual components of the plant show that the maximum exergy losses are in steam turbine operation one (STO ) and steam turbine operation two (STO ). STO and STO are 813 kJ/kg, 1 2 1 2 820 kJ/kg, 822 kJ/kg, and 815 kJ/kg that occurred in the turbine between 2019 and 2021, while the minimum exergy losses in STO and STO are 68 kJ/kg, 150 kJ/kg, 1 2 280 kJ/kg, and 276 kJ/kg that occurred in the boiler system between 2019 and 2021. There was a high energy efficiency of 82% and 80% in the superheater between 2019 and 2021, while 89% in the feed water heater and 73% in the superheater had the same duration. The efficiency of 15% and 21% were the minimum in the pump system between 2019 and 2021, while the turbine had a minimum of 20% and 27% from 2019 to 2021. The highest losses of exergy occurred in the turbine as a result of the irreversibility inherent in the turbine process, corroded turbine blades as a result of wet steam, and low energy delivered to the superheater tubes. It was concluded that the turbine inlet temperature should be increased, more energy delivered to the superheater should be increased, boiler pressure should be increased, and weak feed water heaters should be replaced for better performance of the thermal plant.

System Design, Optimization and 2nd Law Analysis of a 100 MWe Double Reheat s-CO2 Power Plant at Full Load and Part Loads

Super-critical Carbon dioxide (s-CO2) power plants are considered to be efficient and environmentally friendly compared to the traditional Rankine cycle-based steam power plants and Brayton cycle-based gas turbine power plants. In this work, the system design of a coal-fired 100 MWe double reheat s-CO2 power plant is presented. The system is also optimized for efficiency with turbine inlet pressures and the recompression ratio as the variables. The components needed, mass flow rates of various streams and their pressures at various locations in the system have been established. The plant has been studied based on 1st and 2nd laws at full load and at part loads of 80%, 60% and 40%. Operating parameters such as mass flow rate, pressure and temperature have considerably changed in comparison to full load operation. It was also observed that the 1st law efficiency is 53.96%, 53.93%, 52.63% and 50% while the 2nd law efficiency is 51.88%, 51.86%, 50.61% and 48.1% at 100%, 80%, 60% and 40% loads, respectively. The power plant demonstrated good performance even at part loads, especially at 80% load, while the performance deteriorated at lower loads. At full load, the highest amount of exergy destruction is found in the main heater (36.6%) and re-heaters (23.2% and 19.6%) followed by the high-temperature recuperator (5.7%) and cooler (4.1%). Similar trends were observed for the part load operation. It has been found that the recompression ratio should be kept high (>0.5) at lower loads in order to match the performance at higher loads. Combustion and heat exchange due to finite temperature differences are the main causes of exergy destruction, followed by pressure drop.

Performance Analysis and Optimization of Regenerative Gas Turbine Power Plant using RSM

In the present study, a thermodynamic analysis of thermal performance is carried out in a regenerative GT power plant. The optimization procedure of design parameters is realized by the response surface methodology (RSM). The thermodynamic simulations were carried out using the EES code for numerous variables such as compression ratio (2≤rp≤12), inlet temperature (273≤T1≤313K), turbine inlet temperature (1200≤T3≤1600K), and regenerator effectiveness (45≤ε≤85%). Analysis of variance (ANOVA) was carried out to identify the process parameters that influence thermal efficiency (ηth) and specific fuel consumption (SFC). Then, a second-order regression model was developed to correlate the process parameters with ηth and SFC. Consequently, numerical and graphical optimizations were performed to achieve multi-objective optimization for the desired criteria. According to the desirability function approach, it can be seen that the optimum objective functions are ηth=50.61% and SFC=0.117 kg/kWh, corresponding to process parameters T1=273.26K, T3=1597.64K, rp=6.95 and ε=84.89%. Lastly, verification simulations were conducted to validate the importance of the generated statistical models.

High-Temperature Materials for Complex Components in Ammonia/Hydrogen Gas Turbines: A Critical Review

This article reviews the critical role of material selection and design in ensuring efficient performance and safe operation of gas turbine engines fuelled by ammonia–hydrogen. As these energy fuels present unique combustion characteristics in turbine combustors, the identification of suitable materials becomes imperative. Detailed material characterisation is indispensable for discerning defects and degradation routes in turbine components, thereby illuminating avenues for improvement. With elevated turbine inlet temperatures, there is an augmented susceptibility to thermal degradation and mechanical shortcomings, especially in the high-pressure turbine blade—a critical life-determining component. This review highlights challenges in turbine design for ammonia–hydrogen fuels, addressing concerns like ammonia corrosion, hydrogen embrittlement, and stress corrosion cracking. To ensure engine safety and efficacy, this article advocates for leveraging advanced analytical techniques in both material development and risk evaluation, emphasising the interplay among technological progress, equipment specifications, operational criteria, and analysis methods.

Development of a new multi-generation system integrated with the S-Graz and Cu-Cle cycles for ammonia, hydrogen and power generation

A new multi-generation plant incorporated with the ammonia synthesis reactor, a Cu-Cl cycle, and a S-Graz cycle plus a gas turbine cycle for electricity, hydrogen as well as ammonia production recommended and dissected from exergy, energy, exergoeconomic, exego-environmental, and environmental (5E) aspects, in this research. Furthermore, to investigate the effect of input variables on the plant function criteria, exhaustive sensitivity evaluations were carried out and disputed in detail. The exergy and energy yields, the products ‘sum unit cost, the cost rate of environmental penalty as well as the emission rate of the offered poly-generation plant have been 41.16%, 45.57%, 369.6 $/GJ, and 0.0001319, respectively. Besides, the plant provided the net power output, hydrogen, and, ammonia of 151488 kW, 0.2199 kg/s, and 1.884 kg/s, sequentially. Also, the whole exergy destruction rate of the plant was computed at about 128.289 MW. Finally, the sensitivity investigations resulted that increasing the hydrogen molar flow rate and high-temperature turbine (HTT) inlet temperature had a positive effect on the techno-eco-environmental performances of the system.

Enhancing Gas Turbine Power Plant Performance in Tropical Climates by Using Inlet Air Cooling with Desiccant Dehumidification and Evaporative Cooling

Abstract Gas turbine power plants play a crucial role in meeting the growing demand for electrical energy. However, their performance can be hindered by high ambient temperatures and humidity levels in tropical climates, leading to a drop in power output. This study investigates the potential benefits of using inlet air cooling with desiccant dehumidification and evaporative cooling to improve the performance of gas turbine power plants in tropical regions. The results show that this inlet air cooling method, integrating evaporative cooling, desiccant wheel, and Maisotsenko cooler, is a viable alternative for mitigating the performance decrease of gas turbines in hot tropical conditions. Furthermore, the compressor inlet temperature can be reduced on average by 11.5 °C by using turbine exhaust gases to heat the regeneration air utilized in the desiccant wheel for dehumidification. Additionally, the power requirement of the inlet air cooling system amounts to around 0.9 MW compared with an improvement of more than 2 MW in power output at peak temperature. Further research is needed to understand and quantify other benefits related to inlet air cooling, such as reducing emissions of harmful pollutants and operating at higher turbine inlet temperatures.

Fluid–Thermal–Structural Analysis of Partial Admission Axial Impulse Turbines With Liquid Jet Impingement Cooling

Abstract Increasing turbine inlet temperature is beneficial to enhance turbine performance. However, this also results in stringent cooling requirements. Unlike turbines in air cycle machines, the partial admission axial impulse turbines for underwater vehicles can utilize the abundant seawater as the cooling medium. In addition, the short blades cannot accommodate the complex cooling channels used in aero-engines, and the alternative way is jet impingement liquid cooling. This paper proposes a fluid–thermal–structural coupling method to investigate the performance of partial admission axial impulse turbines with water-cooling on the rotating wheel front surface. The volume of fluid multiphase model is employed to study the transient gas–liquid interaction, while the Lee model is chosen to model the heat and mass transfer during phase change. Also, a two-way weakly coupling method among fluid, thermal, and structure is utilized to account for fluid–structure interaction. The results show that the temperature distribution at the turbine wheel drops significantly with the jet impingement liquid cooling. The turbine efficiency is also reduced by 3.38% due to the mixing of cooling medium and gas. From stress analysis, the use of water-cooling can minimize turbine damage and ensure stable turbine operation. This study provides insight into the cooling method for partial admission axial impulse turbines for the underwater vehicle.

Hydrogen combustion in two-stage high-pressure gas turbine—thermal and flow simulations for performance comparison with fossil fuels

Hydrogen energy forms an attractive solution for reducing greenhouse gas emissions from gas turbine systems. Although hydrogen combustion has been widely studied for combustors, only a few studies have considered the combustion effect downstream of the combustor. This study conducted an integral simulation of the combustion and flow of a GE-E3 aero-engine under hydrogen fuel and compared its performance with that of representative fossil fuels such as Jet A in an aero-engine and methane in an industrial gas turbine. All simulations were conducted under a constant heat input at the combustor and turbine inlet temperatures. During combustion simulation, the HyChem mechanism was applied to evaluate the composition of the products in an equilibrium model. Specifically, Reynolds-averaged Navier–Stokes steady simulation of a two-stage high-pressure gas turbine was conducted using the calculated boundary condition from the combustion simulation and k − ω shear stress transport γ turbulence model. The results revealed the high velocity of the hydrogen combustion flue gas owing to its low density under a large pressure difference. Overall, the power output, thermal efficiency, and fuel consumption were improved by hydrogen combustion. The thermal and flow results of the simulation can be used to develop hydrogen gas turbines.

Особливості теплогідравлічних процесів у маслорадіаторі авіаційного газотурбінного двигуна

The modern gas turbine engines (GTEs) development is associated with an increase in the compressor pressure ratio and the gas temperature at the turbine inlet with a simultaneous reduction in the size and weight of the engine. The reliable operation of the GTE largely depends on the oil system excellence. In circulating oil systems, to ensure the lubrication and cooling of engine friction units, a high multiplicity of oil circulation is necessary. The preparation of oil for the next lubrication cycle is related to its cooling, cleaning of mechanical impurities formed during operation, and air separation. Oil coolers are used to cool the oil in GTEs. Air or fuel can be used as the cooling medium. Regardless of the cooling medium choice, a two-phase mixture (oil-air) and not a single-phase oil, as is considered when designing oil coolers, affects the course of thermo-hydraulic processes. Therefore, the subject of this paper is thermohydraulic processes in two-phase media. The goal of this study is to determine the specific aspects of thermohydraulic processes during the oil-air mixture cooling in an aviation gas turbine engine to further improve oil cooler design approaches. This paper aims to show the differences in the course of thermohydraulic processes in two-phase media from single-phase media and to emphasize the importance of considering them when designing oil coolers. The main results are as follows. For a two-phase flow, changes in temperature and pressure change not only the thermophysical properties of the phases but also the gas content, density, and speed of the mixture, which affects the course of thermohydraulic processes in the oil cooler. Under certain combinations of parameters, the structure of the two-phase flow may change. A low value of the equilibrium speed of sound can lead to unpredictable operation of the oil cooler and the oil system as a whole. In addition, the presence of an oil-air mixture reduces the heat transfer capacity of the oil cooler compared with the results of calculations using standard methods. In conclusion, it can be stated that to increase the efficiency of the oil system, it is extremely important to establish the regularities of thermo-hydraulic processes for the two-phase flow of the oil-air mixture and consider this during the design of oil coolers.

Energy and exergy analyses of a recompression supercritical CO2 cycle combined with a double-effect parallel absorption refrigeration cycle

In this study, a new cogeneration system is presented that can make optimal use of the waste heat from the sCO2 power cycle using a double-effect parallel absorption refrigeration cycle (DEARC), generating electricity and refrigeration simultaneously. A comparative study between the proposed (sCO2/DEARC) system and the stand-alone sCO2 power system is conducted to show its advantages and potential. The performances of the sCO2 and sCO2/DEARC systems are evaluated from the energetic and exergetic points of view using an in-house developed thermodynamic simulation platform via Engineering Equation Solver (EES) software. Variables such as pressure ratio, turbine inlet temperature, and evaporator temperature are also used for parametric analysis. The results indicate that the proposed system can generate of 132.72 MW cooling capacity. Also, the results show that the proposed sCO2/DEARC system can achieve a 55.8% and 5.2% improvement in thermal efficiency and exergy efficiency, respectively, with a negligible decrease in net power output (Wnet) compared to the stand-alone sCO2 power plant.

Synergetic characteristic of a novel thermally-driven CCHP system based on supercritical and transcritical CO2 cycles

A novel poly-generation system is proposed based on supercritical carbon dioxide (SCO2) Brayton cycle and transcritical carbon dioxide (TCO2) refrigeration cycle to meet the seasonal energy demand in buildings. The thermodynamic model of the combined cooling, heating and power (CCHP) system was constructed based on the laws of thermodynamics, and seasonal operation modes were also analyzed. The Techno-economic performance of CCHP system was analyzed and compared with the single output systems and organic working fluids. The results show that the temperature of the turbine inlet in SCO2 cycle should be close to the heat source temperature and the temperature of the condenser outlet should be close to the critical temperature. The optimal pressure of the condenser outlet for coefficient of performance is about 9.3 MPa, while it is 8.6 MPa for power generation. The optimum thermodynamic and economic performance cannot be achieved simultaneously. The power generation of CO2 is 13.13% worse than that of organic working fluids and coefficient of performance of former is worse than that of latter. As the manufacturing cost goes down over time, the CCHP system based on CO2 will further improve its economic performance in the future.

Performance Evaluation of a Novel Multigeneration Plant of Cooling, Power, and Seawater Desalination Using Supercritical CO2 Partial Cooling, ME-TVC Desalination, and Absorption Refrigeration Cycles

Multigeneration systems have gained popularity and approval from scientific minds due to the enhancements these systems bring to total energy utilization efficiency. The use of waste heat from different thermodynamic cycles ensures deceleration of environment pollution. In this paper, a newly conceptualized poly-generation system combining power, cooling and desalination is proposed. Despite the high efficiency generated by the next generation supercritical CO2 (sCO2) Brayton cycles, the pre-coolers (cooling components) of the power block experience a substantial amount of low-grade energy loss. Utilizing this energy loss to increase thermal efficiency further has been the driving force behind this research. The proposed system has three subsystems which are sCO2 Partial cooling cycle with reheat for power generation, followed by a ME-TVC (multi-effect desalination-thermal vapor compression) cycle for producing fresh water and finally an absorption refrigeration cycle (ARC) to provide refrigeration effect. The waste heat from precoolers of sCO2 partial cooling cycle are being utilized by the desalination plant and refrigeration cycle for enhanced system performance. A comprehensive mathematical model is developed and a parametric assessment is performed. The parametric investigation focuses on the primary performance parameters, namely net power output, freshwater yield, energy utilization efficiency, coefficient of performance, and gain output ratio, to assess the multi-generation system's performance across various operational scenarios. The variables that are optimized are turbine inlet temperature of the sCO2 cycle, temperature difference of the generator and the evaporating temperature of the absorption cycle, the number and temperature of the effects of the desalination system. The results show that the greatest energy efficiency of the developed system is up to 70%. The 1st law energy efficiency is termed as Energy Utilization Factor (EUF) in the present work. This term adheres to the logic of the first law of thermodynamics by relating the total energy outputs to the system (work plus refrigeration capacity and heat supplied to the desalination plant) to the total energy input. Using the default parameters, the COP of the ARC is 0.667 and the EUF of the combined system is 59%. Both of these values are higher when compared to previous combined cycles found in literature.

Effect of water jet area on mitigation of vortex rope in a Francis turbine

The rotating vortex rope (RVR) is normally formed at part load operating conditions, which develops flow instability in the draft tube (DT) cone of a Francis turbine. The detrimental effects of RVR reduce the life and performance of the turbine. The present work mitigates RVR through axial water jet injection in the DT cone. This paper extends the author's previous work on water injection with a 50% reduction in the water jet area through two nozzles with a diameter of 12.7 mm. The effect of area reduction is analyzed by spectral analysis like power spectrum density and spatial harmonic decomposition of the pressure field measured at the wall of the cone. The effect of water jet injection on synchronous and asynchronous pressure pulsations is analyzed at both measurement planes of the cone. The improvement in pressure recovery in the cone and turbine efficiency due to water jet injection is also analyzed. The water is injected at 0.5%–2% of the turbine inlet flow at 22.10° guide vane opening.

Endwall heat transfer in wedge channel with teardrop pin fins, circular fins and oblong pin fins

Abstract The turbine inlet air temperatures exhibit a significant degree of elevation, hence leading to potential adverse consequences such as the degradation of blade material integrity. Consequently, the necessity to cool the turbine blades has arisen, leading to the implementation of various cooling systems. This study aims to conduct a comparative analysis of three different types of pin fins, namely oblong, circular, and teardrop, in a wedge duct. The range of Reynolds number considered for the analysis is between 10,000 and 70,000, whereas the pin fins and endwalls are subjected to a uniform heat flux of 3280 W/m2. The findings suggest that the friction factor associated with teardrop pin fins is 28.4 % lesser than circular pin fins and when compared to oblong pin fins; it is reduced by 34.5 %. The findings suggest that the friction factor associated with teardrop pin fins is 14 % lower compared to oblong and circular pin fins. The TPF improves with Re, and it is 24.5 % higher than oblong pin fin geometry and 39.2 % higher than circular shaped pin fins.

Comprehensive performance assessment and multi-objective optimization of a new combined cooling, heating and power system with CO2 working fluid

In order to utilize the medium-and-low grade energy sources more efficiently, a new combined cooling, heating and power system using CO2 working fluid is proposed in this paper. The system is coupled by supercritical CO2 Brayton cycle and transcritical CO2 refrigeration cycle, and is characterized by the clever arrangement of some heat exchangers which could recover overall waste heat to generate useful heating capacity. Firstly detailed mathematical models are established to investigate the thermodynamic and exergoeconomic performance of the system. Under the preliminary design conditions with 170 °C heat source, the system could achieve values of 115.49%, 41.37% and 16.84$‧GJ−1 in thermal efficiency, exergy efficiency, and cost of unit product exergy respectively. Then comprehensive parameter analysis are conducted and reveal that within some certain ranges, the decrease of turbine inlet pressure and the increase of turbine inlet temperature, turbine outlet pressure, evaporation pressure and ratio of CO2 mass flow rates would lead to higher exergy efficiency and lower unit product exergy cost. Afterwards multi-objective optimizations performed under two operation modes demonstrate the everlasting high-efficiency of the system at different modes. Finally a performance comparison with a similar system in the literature further proves the superiority of the proposed system.

Performance Model Identification of the General Electric CF34-8C5B1 Turbofan Using Neural Networks

This paper presents a methodology developed at the Laboratory of Applied Research in Active Controls, Avionics, and Aeroservoelasticity to identify a performance model of the CF34-8C5B1 turbofan engine powering the CRJ-700 regional jet aircraft from simulated flight data using artificial neural networks (ANNs). For this purpose, a qualified virtual research simulator was used to conduct different types of flight tests and to collect engine data under a wide range of operating conditions. The collected data were then used to create a comprehensive database for the training of the ANN model. This process was performed using the Bayesian regularization algorithm available in the MATLAB Neural Networks Toolbox, followed by a study to identify the optimal network architecture, namely, the number of layers and the number of neurons. The validation of the methodology was accomplished by comparing the model predictions with a set of flight data collected with the flight simulator for different flight conditions and flight regimes including takeoff, climb, cruise, and descent. The results showed that the model was able to predict the engine performance in terms of fan speed, core speed, inlet turbine temperature, net thrust, and fuel flow with less than 5% relative error.