Fuel Flow Research Articles

Rethinking Energy Geopolitics: Towards a Geopolitical Economy of Global Energy Transformation

ABSTRACT We are in the midst of a global energy system transformation (GEST) which is rewiring the world economy, opening new axes of political contestation, and revolutionising the energetic basis of human civilisation. Energy geopolitics has not yet reconciled itself to this challenge. The field has traditionally been preoccupied with the dependence of Western states on cross-border flows of fossil fuels. More recently, efforts have been made to prospectively map out what the geopolitics of a fully renewable world might look like. What both literatures miss, however, is the very fact of the GEST: that we are living through a changing and contested process of global transformation, across interacting high- and low-emissions systems, whose contours are open and actively constructed over time. In this paper, we start to develop a provisional framework to make sense of the GEST, that is able to capture the full scale of the transformation, and its dynamic, contingent, constructed nature. We attend to three areas of geopolitical economy: the wide-ranging material dimensions of the transformation, its geographical space-making, and its conflict-ridden political economy. We then apply this framework to two case studies, one looking at the fraught role of fossil gas as a ‘transition fuel’, the other at lithium-ion batteries.

Automatic Fuel Flow Regulation System for the Combustion Chamber under Varying Operating Conditions Based on a Neural Nitrogen Oxide Sensor

Automatic Fuel Flow Regulation System for the Combustion Chamber under Varying Operating Conditions Based on a Neural Nitrogen Oxide Sensor

A convolutional neural network prediction model for aviation nitrogen oxides emissions throughout all flight phases

In recent years, there has been an increasing amount of research on nitrogen oxides (NOx) emissions, and the environmental impact of aviation NOx emissions at cruising altitudes has received widespread attention. NOx may play a crucial role in altering the composition of the atmosphere, particularly regarding ozone formation in the upper troposphere. At present, the ground emission database based on the landing and takeoff (LTO) cycle is more comprehensive, while high-altitude emission data is scarce due to the prohibitively high cost and the inevitable measurement uncertainty associated with in-flight sampling. Therefore, it is necessary to establish a comprehensive NOx emission database for the entire flight envelope, encompassing both ground and cruise phases. This will enable a thorough assessment of the impact of aviation NOx emissions on climate and air quality. In this study, a prediction model has been developed via convolutional neural network (CNN) technology. This model can predict the ground and cruise NOx emission index for turbofan engines and mixed turbofan engines fueled by either conventional aviation kerosene or sustainable aviation fuels (SAFs). The model utilizes data from the engine emission database (EEDB) released by the International Civil Aviation Organization (ICAO) and results obtained from several in-situ emission measurements conducted during ground and cruise phases. The model has been validated by comparing measured and predicted data, and the results demonstrate its high prediction accuracy for both the ground (R2 > 0.95) and cruise phases (R2 > 0.9). This surpasses traditional prediction models that rely on fuel flow rate, such as the Boeing Fuel Flow Method 2 (BFFM2). Furthermore, the model can predict NOx emissions from aircrafts burning SAFs with satisfactory accuracy, facilitating the development of a more complete and accurate aviation NOx emission inventory, which can serve as a basis for aviation environmental and climatic research. SynopsisThe utilization of the ANOEPM-CNN offers a foundation for establishing more precise emission inventories, thereby reducing inaccuracies in assessing the impact of aviation NOx emissions on climate and air quality.

Effects of Fuel Flow and Airflow Swirl on Thermal Performance of a Miniature-Scale Combustor for Direct Energy Conversion Systems

Micropower generation and micropropulsion are two emerging fields where micro- and miniature-scale combustors are anticipated to play a significant role. Today, there is a growing interest in combustion-based direct energy conversion modules such as thermoelectric and thermophotovoltaic micropower generators. In this study, the effects of swirl addition to fuel flow and airflow on combustor operational envelope, flame blowout limit, combustion efficiency, exhaust gas temperature, mean outer wall temperature, emitter efficiency, and normalized temperature standard deviation of a miniature-scale (mesoscale) combustor are studied under various equivalence ratios. The findings demonstrate that swirling flows improve the flame blowout limit and operational envelope of the combustor; however, this improvement is more significant for airflow swirl. Besides simultaneous swirling flows of fuel and air result in the highest blowout limit. Additionally, it has been shown that swirl addition improves combustion efficiency and causes a significant amount of heat to be generated, which raises the temperature of the exhaust gas, the mean outer wall temperature, and the emitter efficiency. Furthermore, mean outer wall temperature and emitter efficiency have the highest values for simultaneous swirling flows of fuel and air. It is also observed that increasing the fuel flow swirl number generally lessens the normalized temperature standard deviation (NTSD) and consequently improves the combustor wall temperature uniformity, while for the airflow swirl case, a swirler with 30° vane angle for airstream has a lower NTSD than a 45° vane angle swirler. The results obtained in this study provide useful information for designing a combustion-based direct energy conversion module.

The heat transfer mechanism coupling pyrolysis and flow of hydrocarbon fuel in heated tube under supercritical pressure

The coupling mechanism between pyrolysis and fluid flow of endothermic hydrocarbon fuels plays a crucial role in the design of regenerative cooling systems for advanced aircraft. In this work, the convective heat transfer for HF-1 with pyrolysis including 18 species and 24 reactions is numerically investigated in a horizontal circle tube under supercritical pressure (5 MPa). The results show that the mechanism of small molecule products on different heat transfer phenomena varies. In the inlet heat transfer deterioration region, small molecule products exacerbate the non-uniform radial distribution of fluid density and dynamic viscosity. At the outlet position, it significantly enhances the physical heat sink of the mixture with its high thermal conductivity and specific heat capacity. Additionally, the aromatic hydrocarbons significantly contribute to non-uniformities in thermal conductivity and specific heat capacity due to the low specific heat capacity and thermal conductivity in inlet HTD region. When the radial non-uniformity coefficient of fuel conversion keeps between −0.1 and 0, the pyrolysis of the fuel enhances heat transfer, remarkably.

Theoretical principles of formation of homogeneous fuel mixtures in diesels

The article discusses molecular changes in the working mixture based on the composition of the biofuel blend. Theoretical calculations on the variations in heat release rates and fuel particle velocities reveal differing increases in heat utilization efficiency across various flow sections during atomization at different time intervals. The movement conditions of particles within the combustion chamber vary, particularly in fuels with multicomponent mixtures. Notably, a significant number of droplets (up to 20 million) of varying sizes are observed. Under these circumstances, abrupt spraying speeds are not recommended as they lead to fuel accumulation around the burner, hindering the combustion process. Furthermore, the article introduces analytical relationships aimed at promoting turbulence in flows of diverse fuels within the combustion chamber through the intensive mixing and throttling of fuel mixtures with varying compositions.

Experimental and Model Investigation of a Solid Oxide Fuel Cell Operated Under Low Fuel Flow Rate

A state-of-the-art anode-supported Ni-YSZ/YSZ/GSC/LSC SOFC with 16 cm2 cathode area was tested at low anodic flow rate (6.25 Ncc min−1 cm−2) and large excess of air (93.75 Ncm3 min−1 cm−2). These conditions are typical of stacks, where high H2 utilization is targeted, but are uncommon in single cell testing. H2-based mixtures were supplied between 550 °C and 750 °C, varying the partial pressure of H2 (between 93% and 21% with 7% H2O mol/mol) and H2O (between 10% and 50% H2O with 50% H2). I/V and EIS measurements were collected and analyzed with a 1D+1D model of a SOFC with rectangular duct interconnectors. At 750 °C and 93% H2, 58% fuel utilization was obtained, which raised to 81% at 21% H2, driving the SOFC under internal diffusion control. The model analysis confirmed that nearly-isothermal conditions were retained thanks to efficient heat dissipation, and that air acted as a coolant. During testing, the contact resistance grew to 0.16 Ω cm2 at 750 °C, limiting the SOFC’s performance to a maximum power density of 340 W cm−2 with 7% humidified H2. The kinetic parameters of the anodic reaction were derived by fitting, finding a positive order for H2 (+0.9), and a negative order for H2O (−0.58).

Design and Build of Modification of Fuel Flow as a Tool for Aircraft Refueling in the Hangar of the Aviation Polytechnic of Surabaya

This plan is motivated by the results of observations regarding the teaching and learning process for Cadets of the Surabaya Aviation Polytechnic, during the run-up and refueling practicum processes. This tool is planned to overcome the inefficiency of the refueling equipment in the Surabaya Aviation Polytechnic hangar, because when cadets do refueling it is not accurate to calculate the fuel that has entered the plane. In making this tool, applying microcontroller technology to a flow meter with a digital display by utilizing Arduino as a fuel flow measurement controller and for a flow meter sensor which functions to calculate the flow of fuel flowing through the tool, the results of the fuel meter measurements are then processed by Arduino which has been Fill in the program then the results are displayed on the LCD display.

Turbulence Statistics of Thermo-Buoyancy Supercritical Fuel Flow in a Regenerative Cooling Channel

Turbulence Statistics of Thermo-Buoyancy Supercritical Fuel Flow in a Regenerative Cooling Channel

Data-based modelling of proton exchange membrane fuel cell performance and degradation dynamics

Proton exchange membrane fuel cell (PEMFC) is in the commercial adoption process for hard-to-decarbonize applications such as transport. However, its long-term durability, reliability, diagnostics, and performance remain a critical challenge. In this study, the data-based modelling technique, artificial neural network (ANN), is adopted to comprehend performance degradation and thermal and pressure dynamics. Experimental data consisting of polarization and cyclic voltammetry data are acquired after every 6,000 accelerated stress test (AST) degradation cycles as stipulated by the US Department of Energy guidelines. Over 40,000 test cases were considered for training and evaluating the neural network comprising data from 30,000 full-cell AST cycles. Fuel cell operating temperatures, pressures, flow rates, and relative humidities are varied to capture the entire spectrum of PEMFC performance characteristics. Parameters such as the number of AST cycles endured or instantaneous catalyst electrode surface area, operating current density, reactant flow rate, relative humidity, system temperature and pressure are considered as feature vectors (inputs) to predict cell output voltage, reactant outlet pressure and temperature for both anode and cathode streams. Data preprocessing and batch learning are implemented in Python to improve prediction accuracy and computational time; considering the substantial nonlinear data sets, various Keras library optimizers and corresponding hyperparameters are investigated for better convergence. The trained neural network model is evaluated on 15,000 test cases resulting in an R2 ≥ 0.995 for all the predicted variables, demonstrating the capability of data-based models to accurately predict the nonlinear behavior of such electrochemical systems with minimal processing time, advocating for their application in real-time system monitoring, controls and diagnostics.

Digital twin for Electronic Centralized Aircraft Monitoring by machine learning algorithms

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.

Flow Boiling of Liquid n-Heptane in Microtube with Various Fuel Flow Rate: Experimental and Numerical Study.

The evaporation of liquid hydrocarbon n-heptane is discussed in detail with experimentation and numerical techniques. A maximum wall temperature of 1050 K was reported during an experimental process with a two-phase flow that was stable and had a prominent meniscus at a small fuel flow rate (FFR) ≤ 10 µL/min. At medium to high FFR (30-70 µL/min), the flow field was unstable, with nucleating bubbles and liquid droplets inside the microtube and the maximum temperature recorded was 850 K for 70 µL/min. For the numerical model, the temperature of the wall was used as a boundary condition. Using the numerical model, the evaporative flux at the meniscus, pressure drop, pressure oscillation, and heat transfer coefficient (HTC) were investigated. A single peak in HTC was obtained at a low fuel flow rate, while multiple peaks were obtained for high FFR. At low FFR, the pressure peak was observed to be 102.4 KPa, whereas at high FFR, the pressure peak increased to 105.5 KPa. This shows a 2% increase in pressure peak with an increase in FFR. Similarly, when the FFR increased from 5 µL/min to 70 µL/min, the pressure drop increased from 500 Pa to 2800 Pa. The high amplitude of pressure drops and a high peak of HTC were found, which depend on the mass flow rate. The coefficient of variation for pressure drop depends mainly on the fuel flow rate.

A conjugate numerical model for the thermal analysis of the regenerative cooling of an X-51A-like aircraft

A conjugated computational fluid dynamics model using convective thermal boundaries is proposed for the thermal analysis of the regenerative cooling system of an X-51A-like hypersonic aircraft in conditions closer to realistic scenarios. By X-51A-like, we mean that the convective boundaries of the cooling system are determined according to the structure and flight conditions (Mach 6 and an altitude of 20 km) of the X-51A Waverider. The aerodynamic heating, supersonic combustion, and convective heat transfer with an interior (fuel tank) are simulated from an engineering perspective. The flow, heat transfer, and pyrolysis characteristics of endothermic hydrocarbon fuels (EHFs) flowing in B-channels (bottom), S-channels (side), and T-channels (top) considering buoyancy effect are simulated and compared. A distinct temperature distribution difference in the solid region is observed between the cases with different boundary conditions. However, the cooling performance of EHFs is insensitive to the type of thermal boundary. Five indices, the maximum temperature, outlet temperature, n-decane conversion, total heat sink, and pressure drop, are compared to comprehensively assess the cooling performance. The cooling demands in the B-channels and S-channels are about 1.3 times those in the T-channels because of the additional cooling effect from the adjacent fuel tank. This study should be of great significance in the practical and systematic design of regenerative cooling systems.

Study of the Influences of Fuel Utilization on Efficiency and Anode Safety at Different Fuel Flow Rates for Industrial-Size Solid Oxide Fuel Cell

Solid oxide fuel cell (SOFC) is regarded as a promising energy conversion technology that can directly produce electricity from chemical fuels without combustion. Commercialization of SOFC systems has already started with residential and industrial applications, and demonstrations for a broader range of uses have been carried out. However, the widespread commercialization of SOFC systems requires further improvements both in efficiency and durability. The efficiency of a single cell is affected by fuel utilization and voltage. In addition, high fuel utilization may cause an increase in concentration polarization or lead to local Ni oxidation of cell anode. Therefore, it is imperative to study the influence of fuel utilization on the cell's performance, efficiency, and anode safety. In this work, I-V curves at different fuel flow rates were tested. The fuel utilization and voltage corresponding to the peak power density at different flow rates were determined. Based on the gas conversion and diffusion resistance models, the area specific resistance behavior and the fuel utilization corresponding to the beginning of the concentration polarization zone were investigated. Besides, the effects of fuel utilization and cell voltage on local Ni oxidation were also studied. The results indicated that at a low fuel flow rate of 0.1-0.3 L/min, the fuel utilization corresponding to the peak power density condition (which is also the condition of maximum efficiency) was about 90%. Although a significant increase in concentration polarization occurred under such high fuel utilization, no Ni oxidation occurred due to the high voltage. However, at a high fuel flow rate of 0.8-1.0 L/min, the fuel utilization corresponding to the peak power density condition was about 70%. The low voltage led to local Ni oxidation before entering the concentration polarization zone. This finding provides an idea for choosing fuel utilization at different fuel flow rates to realize high efficiency and anode safety.

Experimental Demonstration of the Electric Efficiency with BZYb based Protonic Ceramic Fuel Cell

Protonic Ceramic Fuel Cell (PCFC) is expected to be the next-generation fuel cell for its higher energy conversion efficiency and lower operation temperature. BaZrO3 based oxide are potential materials as PCFC electrolyte because they have a high chemical stability under CO2 condition and high proton conductivity. We have developed PCFC using BaZr0.8Yb0.2Ox (BZYb) as the electrolyte and performed max power density 0.49 W cm–2 at 873 K. For practical use of PCFC, it is needed to conduct the higher electric efficiency and to improve the durability. Especially, improving the electric efficiency of PCFC might be difficult due to the internal current leakage by the hole creation.In this work, we have evaluated the electric efficiency using a Φ60mm anode supported PCFC (active electrode area: Φ45mm, 15.9 cm2). Thin and dense BZYb electrolyte is supported on porous Ni-BZYb cermet anode and La0.6Sr0.4CoOx cathode. The effect of fuel utilization on PCFC cell was examined and the electric efficiency of PCFC was calculated as follows:η = V / (-ΔH / nF) × Ufwhere the n and F are the mole number and the Faraday constant, respectively. ΔH is the standard combustion enthalpy of hydrogen or methane. The value of -ΔH / nF is 1.24 V or 1.04 V in the case of hydrogen supply or methane supply respectively. V is the cell voltage and Uf is the fuel utilization.Φ60mm anode supported PCFC was fabricated by tape-casting process used for the industrial production of ceramic electronic devices. NiO-BZYb anode slurry and BZYb electrolyte slurry were prepared by mixing the powder, binder, solvents and plasticizer. And then, these slurries were tape-casted respectively. The anode green sheets and the electrolyte green sheets were stacked and pressed. The anode electrolyte half-cell was obtained by firing this laminate at 1673–1773 K for 2 h. La0.6Sr0.4CoO3-δ (LSC) paste was applied to the surface of the half-cell by screen–printing, and then, fired at 1223 K for 2 h to form a cathode.The electrochemical performance of the Φ60mm anode supported PCFC was investigated at 873 K under the conditions of a humid fuel gas (i.e., 3% H2O, 48.5% N2 and 48.5% H2) and a humid air (i.e. 3% H2O and 97% air). Fuel flow rate were determined by the operational current and the fuel utilization (Uf), and air flow rate were constant at 264 cc min–1, which the air utilization (Uair) was 30% at the current of 0.3 A cm–2.Figure 1 shows the comparison of the current-voltage (I-V) and current-power (I-P) characteristics of Φ60mm and Φ20mm BZYb cell. Fuel flow rate was 100 cc min–1 at this experiment. The same electrochemical performance was observed, and the maximum power reached 7 W at 12.9 A in the case of the Φ60mm cell.Figure 2 shows the cell performance of 0.3 A cm–2 current density under the various Uf condition. The theoretical voltage line was also drawn in the figure, which was calculated by Nernst equation used the PH2 in the anode outlet gas, PO2 and PH2O in the cathode outlet gas. Cell voltage followed the same path as the theoretical voltage in the low Uf condition (Uf≦70%). On the other hand, the gap between the cell voltage and theoretical one was larger in the higher Uf condition (Uf≧80%). Anode gas diffusion overvoltage might be increased by PH2 decreasing in anode gas or the imbalanced gas flow due to decreasing the anode gas flow rate. We demonstrated that BZYb based PCFC could be operated at high Uf condition (i.e., Uf=90%) and the maximum electric efficiency was 55% (DC). This presentation is partially based on results obtained from a project, JPNP20003, commissioned by the New Energy and Industrial Technology Development Organization (NEDO). Figure 1

Hydrocarbon Fuel Flow and Heat Transfer Investigation in Rotating Channels

Ram air turbines are used in the power generation systems of hypersonic vehicles, which can address the problem of the high power consumption of weapon systems. However, high incoming air temperatures can cause the turbine blades of power generation to ablate. At this point, the incoming air can no longer be used as a cooling source to cool the turbine blades. To prevent the ablation of the turbine blades of the hypersonic vehicle power generation, hydrocarbon fuel carried by the hypersonic vehicle itself is used to cool the turbine blades. Hence, hydrocarbon fuels under rotating conditions are investigated. The results show that the rotation leads to a strong pressure gradient that causes the density and dynamic viscosity of hydrocarbon fuel to increase dramatically. Compared to the static condition, the density and dynamic viscosity of the hydrocarbon fuel increase by a maximum of 65.1% and 405%, respectively, under the rotating condition. This leads to an obvious reduction in velocity. The comprehensive influence of the physical properties of the fuel, centrifugal force, and Coriolis force causes the convective heat transfer coefficient and Nusselt number of the channel to first increase and then decrease with the increase in the rotational speed. Compared to the static condition, the convective heat transfer coefficient and Nusselt number increase by a maximum of 69.7% and 45.6%, respectively, under the rotating condition. The critical rotational speed of the Nusselt number from rise to fall is 20,000 rpm for different inlet temperature conditions.

Noninvasive Fuel Flow Monitoring System for Vented Fuel Oil Heaters

In this work, we present hardware and firmware design and preliminary testing results for a noninvasive device for measuring fuel oil consumption in fuel oil vented heaters. Fuel oil vented heaters are a popular space heating method in northern climates. Monitoring fuel consumption is useful to understanding residential daily and seasonal heating patterns and understanding the thermal characteristics of buildings. The device is a pump monitoring apparatus (PuMA) that employs a magnetoresistive sensor to monitor the activity of solenoid driven positive displacement pumps, which are commonly used in fuel oil vented heaters. PuMA accuracy for calculating fuel oil consumption was evaluated in a lab setting and found to vary up to 7% from the measured consumption value during testing. This variance will be explored more in field testing.

Numerical simulations of the flow of a kerosene gel: Effects of thixotropy and shear-thinning

The ability of a gel to act like a solid-like material at rest and flow like a liquid when sheared can be very useful in propulsion system. Numerical simulation of the flow of gel fuels can be used as a reference to assist experimental studies and applications of these materials. Non-linear rheological effects such as shear thinning, yield stress, thixotropy and viscoelasticity can create difficulties in the formulation and in the numerical investigations. This paper uses a thixotropic shear-thinning constitutive relationship while using a second-order kinetic equation for the structural parameter, where the Carreau–Yasuda model is used for a 5% organic kerosene gel. We study the simple shear flow to verify the accuracy of the numerical method, and the impact of the constitutive parameters on the apparent viscosity as a function of shear rate. To look at the thixotropic flow in more complex flows, we initially study the pipe flow of an organic kerosene gel for different pumping conditions. After performing a parametric study, we find that the thixotropy of the gel strongly affects the shear history, that is, the nonuniform aging distribution. The destruction of the microstructure can be accelerated by adjusting the flow intensity and the model parameters, but it seems that it is difficult to arrive at the equilibrium state within the time scale of the propulsion system; this poses a challenge to the design of the system.

Evaluation of the Arteriovenous Difference Technique to Simultaneously Estimate Protein Synthesis and Degradation in the Hindlimb of Fed and Chronically Underfed Steers

Our objectives were to validate a technique to measure protein turnover based on net fluxes of tyrosine radioactivity and mass across the hindlimb, and to describe the impact of nutrition on hindlimb protein kinetics and nutrient utilization in growing Holstein steers. External iliac vessels were catheterized to allow for measurements of hindlimb arteriovenous (AV) differences and blood flow. Animals were used in a single reversal design with 16-d periods. Treatments were either 60% (0.6M) or 220% (2.2M) of the energy required for maintenance. On d 12 and 14 of each period, a primed-continuous infusion of L-[side chain-2,3-3H]tyrosine was initiated, followed by a 4-h sampling period to assess hindlimb nutrient utilization and protein kinetics. Well-fed steers exhibited rates of hindlimb utilization for non-nitrogenous energy substrates and amino acids that were consistent with values previously reported for well-fed ruminants. Underfeeding decreased hindlimb blood flow (62%), oxygen consumption (51%) and utilization of respiratory fuels (64-73%). Protein synthesis was also reduced (49%), leading to net nitrogen loss from the hindlimb. The estimated energy cost of protein synthesis accounted for 13% of hindlimb oxygen consumption across intake levels. Hindlimb protein balance was consistent with whole-body balance, adding credence to derived rates of degradation. Overall, data support the validity of the AV difference technique to estimate components of hindlimb protein turnover.

Detailed Analysis of Aircraft Fuel Flow Using Data from Flight Data Recorder

This paper aims to perform accurate prediction of fuel flow (FF) by employing various models: deep learning (DL), random forest (RF), generalized linear model (GLM), and the Eurocontrol Base of Aircraft Data (BADA) model, and to examine the link between FF and different aircraft performance parameters. The flight data set used in this study is obtained from real turbofan engine narrow-body aircraft performing short-distance domestic subsonic flights, containing a total of 2,674 cruise flights between 31 city pairs. Several statistical error analyses are conducted to compare the performance of the models. Root mean square error, mean absolute error, and mean squared error values for DL are calculated to be 0.01, 0.008, and 0.0001, respectively. On the coefficient of determination ( [Formula: see text]) test for validation, the DL model has the highest value of 0.94. Results of the analysis in this paper show that the DL model offers the best ability to predict FF in all statistical tests, which makes it the best-suited model to estimate FF. These findings can provide the means to make more efficient trajectory planning and forecasts in air traffic management, and more accurately predict fuel consumption of aircraft, thereby decreasing emission levels of carbon gases and of various pollutants and airline operating expenses from fuel costs.