Aydın, Emre; Ermeydan, Ahmet; Turan, Onder

Efficient fuel use is crucial for optimizing aircraft performance, especially in medium-range commercial operations. This study introduces a dynamic thrust-drag modeling technique for a narrow-body jet aircraft powered by a CFM56-7B turbofan engine. It aims to explore the relationship between thrust and fuel consumption using real-world flight data. A physics-based model estimates thrust and drag forces by incorporating parameters such as flap angle, pitch angle, altitude, ground speed, and landing gear position. These parameters are extracted from the Flight Data Recorder (FDR) across multiple Boeing 737 flights. The analysis reveals a strong correlation between fuel flow and thrust, with drag values for flap angles of 15°, 30°, and 40° consistently ranging between 5000 and 10,000 lbf. This study is significant as it enables precise thrust calculations across various flight phases using FDR data. Notably, the thrust force calculated independently of fuel consumption correlates strongly with fuel flow. The findings from this analysis will enhance aero engine functionality and contribute to reducing aircraft energy consumption and emissions.

Atasoy, Vehbi Emrah

Accurate engine thrust modelling offers notable opportunities for reducing fuel consumption, mitigating emission effects, managing air traffic, and optimizing the preliminary design of aircraft. This study focuses on the development of machine learning models to predict the low-pressure rotor speed (N1) parameter, which is closely related to the thrust of turbofan engines, for commercial aircraft during the cruise phase. The analysis utilizes a Flight Data Recorder (FDR) dataset from 1086 actual flights involving twin-engine, narrow-body, short-to-medium haul commercial aircraft equipped with CFM56-7B turbofan engines. To achieve accurate N1 parameter predictions, the study employs machine learning models, including Deep Learning (DL), Random Forest (RF), Gradient Boosted Machines (GBM), and Artificial Neural Networks (ANN). These models are evaluated using statistically significant indicators, demonstrating that machine learning models yield highly accurate results. Among the models tested, the DL model provides the most precise estimates of the N1 parameter. This study not only advances the understanding of engine thrust modelling through machine learning but also provides practical insights for the aerospace industry. The findings underline the potential of machine learning techniques in delivering superior prediction accuracy, which can be integrated into real-time flight management systems, ultimately contributing to more sustainable and efficient aviation operations.

Kilic, Ugur; Yalin, Gorkem; Cam, Omer

Electronic Centralized Aircraft Monitoring (ECAM) parameters play a vital role in the operation of an aircraft to reduce the workload of the cockpit crew. A wide-body commercial aircraft with a triple-spool turbofan engine is examined within the scope of the study. This study is focused on the estimation of the ECAM primary engine parameters: Engine Pressure Ratio, Exhaust Gas Temperature, Fuel Flow, and Shaft Speeds without any additional measurement for data continuity. The recorded flight data obtained from a commercial aircraft is processed with machine learning methods, and the most suitable estimation method is tried to be determined. Correlation analysis is carried out for each data in the study to show strong predictor candidates. The modeling process is conducted by using MATLAB. Results indicate that the Fine Decision Tree is better at memorizing data, while the Wide Neural Network is better at generalizing data. Computational results show that the developed models are outstandingly precise and accurate to estimate aircraft's ECAM data to ensure flight safety for health and performance monitoring of an engine. Thus, when an unreliable situation occurs while performing the flight in practical conditions, the cockpit crew will be able to overcome this situation by Digital Twin.

Kalkan, Orhan; Celen, Ali; Bakirci, Kadir

Mini channeled cold plates (MCCP) are an impressive choice for electric vehicles with a liquid-based thermal management system to keep the battery temperature within the desired range and to achieve a homogeneous temperature distribution. This paper came up with an optimum solution for maximum battery temperature (MBT), maximum temperature difference on the battery surface (MTD) and pressure drops in the channels (ΔP), which are vital parameters. Multi-objective optimization of geometric parameters and coolant flow rate of a designed MCCP which is experimentally investigated is carried out using the Desirability Function Approach. Firstly, the design of experiments (DoE) is generated using response surface method after determining the input variables and their levels. Then, each sample of DoE are modeled and analyzed numerically. Furthermore, the regression equations of the objective functions (MBT, MTD and ΔP) depending on the design parameters are developed and their variance analyzes are performed. Prediction accuracies of model equations developed for MBT, MTD and ΔP are 97.75%, 95.49% and 97.15%, respectively. As a result, optimum values of design variables, namely channel width (mm), distance between branches (mm), channel depth (mm), number of crossovers in branches and coolant flow rate (l/min) are 5, 5, 10, 13 and 0.7061, respectively.

Yilmaz, Harun; Yilmaz, Ilker

In this study, initially, 50%H2–25%CH4–25%CO2, 60%H2–20%CH4–20%CO2 and 70%H2–15%CH4–15%CO2 mixtures were combusted in a laboratory scale-swirl stabilized-premixed combustor so as to specify combustion and emission characteristics of respective gas mixtures. Later on, such mixture flames were exposed to acoustic perturbations at different frequencies between the values of 65–205 Hz and under these conditions, flame response was evaluated. The acoustic perturbations were intentionally created by loudspeakers located in side arms of the T-shaped combustor. Two openings on the combustor walls, and photodiodes and pressure sensors assembled in the experimental apparatus enabled interpreting flame response. During experiments, inlet parameters (such as thermal power – 4 kW, equivalence ratio – 0.5, mixture temperature, etc.) and geometric swirl number (1.2) were kept constant, and tested flames were acoustically forced for 30 s at each frequency step. Results showed that thermal Zeldovich mechanism doesn't dominate NOx formation for tested flames, and 50%H2–25%CH4–25%CO2 mixture emits nearly thirty times of magnitude of higher NO than 70%H2–15%CH4–15%CO2 mixture. Besides, the onset of flame instabilities depending on the forcing frequency isn't controlled by gas composition. However, flame and combustion chamber acoustics weakly couple, hence pressure and heat release rate oscillations weaken as hydrogen amount in gas mixture increases.

Eleyan, Mohammed I.Abu; Çatık, Abdurrahman Nazif; Balcılar, Mehmet; Ballı, Esra

This study investigates and estimates long-run time-varying income and price elasticities of oil demand in Brazil, Russia, India, China, and South Africa (BRICS). A time-varying cointegration (TVC) approach allowing for the smooth changes in the parameters is employed, using quarterly data covering the period from 1990:Q1 to 2018:Q4. TVC tests confirm the variation in the long-run parameters over time for all countries by rejecting the null hypothesis of time-invariant cointegration. Moreover, results reveal that time-varying parameters of income and oil prices are inelastic for all counties’ oil markets. BRICS's oil demand is significantly affected by the real economic activity, although the evidence on inelastic income implies oil as a necessary commodity. The sign of time-varying price elasticities implies oil as an ordinary good for Brazil, Russia, and China whereas an inferior good in some intervals for India and South Africa. The evidence on the insignificance of price elasticities in most of the analysis periods indicates that regulation of oil product prices cannot control domestic oil demand. Hence, one can infer that taxes imposed on petroleum product prices are not an effective policy instrument to reduce greenhouse emissions.

Balli, Esra; Nazif Çatık, Abdurrahman; Nugent, Jeffrey B.

This paper investigates the effects of oil supply and demand shocks on the current account balances of China and Russia for the period between the first quarter of 1993 and the third quarter of 2018 using a time-varying parameter vector autoregression (TVP-VAR) model with stochastic volatility. To facilitate comprehension of the results and to anchor them in well-known events, this analysis focuses on two countries with different oil trade characteristics—Russia as an oil exporter and China as an oil importer. We find that identifying their sources plays an important role in understanding the impact of oil price shocks on trade balances. The results indicate that oil demand shocks have a much larger effect on trade balances and are more attributable to oil price shocks than oil supply shocks. Due to their different positions in the global oil market—one an oil exporter and the other, an oil importer—China's and Russia's individual responses differ substantially. In line with findings regarding impulse responses, the time-varying forecast error decompositions demonstrate that both oil supply and demand shocks have their greatest influence during and immediately after periods of crisis.

Özbek, Emre; Yalin, Gorkem; Ekici, Selcuk; Karakoc, T. Hikmet

Fossil fuels are being depleted day by day. The dependency on fossil fuels must be eliminated in the following years. Also, in the matter of emissions, the cleaner energy generation and usage techniques must be evaluated. The aviation industry is a big energy consumer nowadays. More electric aircraft and All-electric aircraft concepts are being worked on globally to achieve a sustainable aviation industry. Though the electric motors can produce enough thrust force for airliners, due to energy storage technology limitations, the thrust force can't be sustained for a long duration flight. Battery technologies are being developed to overcome these limitations. Moreover, hybrid energy systems and sustainable onboard energy generation systems are trending to achieve sustainability. Fuel Cell and Hybrid Fuel Cell systems are two of the feasible onboard energy systems. The applications of these systems on UAVs (Unmanned Aerial Vehicle) produce data for later studies. The system's behavior during flight phases must be examined on platforms like mini UAVs to understand the system capabilities. In this work, the development phases of a mini UAV designed for Hybrid Fuel Cell flight are introduced. Design philosophy and methodology for designing a UAV with a hybrid propulsion system, limitations of such designs and iterations required during the flight tests are explained. Also, the detailed design estimations of power consumption and final power consumption data collected from flight tests of the aircraft were compared to provide valuable data for following power consumption limited aircraft design studies.

Yilmaz, Harun; Yilmaz, Ilker

This paper presents the results of experimental studies conducted on premixed CNG/H2/CO/CO2 blending synthetic gas flames in a laboratory scale combustor, with particular emphasis on effects of swirl number (from 0.2 to 1.6, at intervals of 0.2) and equivalence ratio (0.6, 0.8 and 1.0) on combustion and emission characteristics of such mixtures. Furthermore, effects of swirl number on lean blowout and flashback limits of studied mixtures were also investigated. Irrespective of the swirl number and equivalence ratio, H2/CO ratios of tested gas mixtures were kept constant (1.0), and mixtures of H2/CO/CNG/CO2 which were diluted with different amount of CO2 (0–20%, at intervals of 5%) were derived. Considering broadest operating range, mixture of 20%CNG/30%H2/30%CO/20%CO2 was determined as base fuel to be tested. Combustion and emission behavior of tested gas mixtures were assessed by examining axial and radial temperature, NOx, CO and CO2 distributions. Besides, swirl number and equivalence ratio effects on flame structure were evaluated by investigating instantaneous flame images (with the same focal length and exposure time). Results of this study showed that effects of swirl number on flame characteristics (temperature and pollutant emission distributions) is not monotonous, and equivalence ratio dependent flame behavior alters differently at different swirl numbers.

Yilmaz, Harun; Cam, Omer; Yilmaz, Ilker

In this study, effect of micro combustor geometry on combustion and emission behavior of premixed hydrogen/air mixtures is numerically investigated. An experimentally tested micro combustor geometry is varied by establishing a cavity or a backward facing step or micro channels inside the combustor. Considering effect of combustor geometry on the amount of heat transferred through wall based on outer wall and combustor centerline temperature distributions, combustion behavior is analyzed. Emission behavior is examined by means of mixing conditions, combustion efficiency and maximum temperature value which are highly bound to geometric properties of a micro combustor. Turbulence model used in this study is Renormalization Group k-ε. For turbulence chemistry interaction, Eddy Dissipation Concept model is used. Multistep combustion reaction scheme includes 9 species and 19 steps. Numerical results obtained from this study are validated with published experimental data. Results of this study revealed that combustion in such combustors can be improved by means of quality of mixing process, residence time, combustor centerline and outer wall temperature distributions, conversion rate of input chemical energy to utilizable heat and emanated NOx levels from combustor outlet with proposed geometric variations.