Aircraft Applications Research Articles

Comparative characterization of entropy and heat transfer in carbon-based magnetohydrodynamic Cross nanofluids flowing through PTSCs: advancing thermal applications for solar-powered aircraft

ABSTRACT The integration of solar energy into aero-technology has emerged as a pivotal solution to meet the escalating energy demands of contemporary societies. This study explores the potential of solar power in aerospace, aiming to reduce carbon dioxide emissions, diminish reliance on environmentally harmful energy sources, and enhance overall industry energy efficiency. The investigation focuses on the integration of solar energy into aero-technology using parabolic trough solar collectors (PTSCs) embedded in aircraft. Particularly, the study delves into the flow and thermal aspects of ethylene glycol magnetohydrodynamic (MHD) Cross nanofluids, in combination with three distinct carbon-based nanoparticles – namely graphene, multi-walled carbon nanotubes (MWCNTs), and single-walled Carbon NanoTubes (SWCNTs) – within the PTSC, which are situated in various sections of the aircraft. Evaluating heat efficiency and heat transfer involves considering various physical phenomena. The results reveal significant enhancements, as observed in the magnetohydrodynamic flow of Cross nanofluids incorporating graphene, MWCNTs, and SWCNTs, where we demonstrate relative increases in maximum heat performance by 35.1009%, 49.9765%, and 67.6678%, respectively. Additionally, the absolute value of the skin friction coefficient showed respective relative increases of 65.2767%, 58.31438%, and 66.4392%. Furthermore, the heat transfer exhibited respective relative increases of 58.3686%, 51.3771%, and 43.0085%.

Radiation effect on stagnation point flow of Casson nanofluid past a stretching plate/cylinder

The exclusive behaviour of nanofluid has been actively emphasized due to the determination of improved thermal efficiency. Hence, the aim of this study is to highlight the laminar boundary layer axisymmetric stagnation point flow of Casson nanofluid past a stretching plate/cylinder under the influence of thermal radiation and suction/injection. Nanofluid comprises water and Fe3O4 as nanoparticles. In this article, a novel casson nanofluid model has been developed and studied on stretchable flat plate or circular cylinder. Adequate rational assumptions (velocity components) are employed for the transformation of the governing partial-differential equations into a group of non-dimensional ordinary-differential formulas, which are then solved analytically. The momentum and energy equations are solved through the complementary error function method and scaling quantities. Using various figures, the effects of essential factors on the nanofluid flow, heat transportation, and Nusselt number, are determined and explored. From obtained results, it is observed that the velocity field diminishes owing to magnification in stretching parameter B\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$B$$\\end{document} and Casson fluid parameter Λ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Lambda$$\\end{document}. The temperature field increases by amplifying radiation Nr\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$N_{r}$$\\end{document}, and solid volume fraction parameter ϕ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\phi$$\\end{document}. The research is applicable to developing procedures for electric-conductive nanomaterials, which have potential applications in aircraft, smart coating transport phenomena, industry, engineering, and other sectors.

Analysis of mechanical properties and free vibrational characteristics of novel Grewia optiva/basalt fiber reinforced hybrid polymer composites

AbstractThis study emphasize on the fabrication and testing of Grewia optiva/Basalt fiber reinforced polymer composites for use in internal applications of automobiles and aircraft. The study investigates the use of Grewia optiva fiber (local plant based fiber) with Basalt fiber, where chopped Basalt fiber (6, 9, and 12 mm) is reinforced in polyester matrix in combination with Grewia optiva fiber. Composite test specimen are fabricated and analyzed using a smart actuation system to evaluate the free vibrational behavior of the composites experimentally. The impact of various parameters including length of the fiber and its weight percentage on the free vibrational behavior of composites is determined. The percentage of individual reinforced fiber is varied (0, 4, 8, and 12 wt.%) maintaining fiber weight % constant, that is, 12 wt.% of composite. The experimental results help to identify the variations in natural frequencies of Basalt/Grewia optiva fiber based composites. B12/GO0 demonstrate the natural frequency of 67 Hz and 44.71 MPa tensile strength for 12 mm fiber reinforced composites. The finding from this experimental work provide insights into the potential applications of Basalt/Grewia optiva fiber reinforced composites for automobile and air craft industries.

Parameter Tuning of a Vapor Cycle System for a Surveillance Aircraft

Surveillance aircraft perform long-duration missions (>eight hours) that include detection and identification of objects on the ground, the water, or in the air. They have surveillance systems that require large amounts of cooling power (typically 10 s of kW) for long durations. For aircraft application, vapor cycle systems (VCS) are emerging as a more efficient alternative to conventional cooling systems. In this study, a two-part method was applied to a cooling system with a VCS that can be installed on a surveillance aircraft. The first part focused on a parameter tuning study set-up and demonstrated how after identifying the operating conditions, constraints, and requirements, the only cooling system parameter available for tuning was the VCS compressor speed. The second part focused on a modelling and solving strategy for the cooling system and showed how the capacity of an aircraft cooling system was impacted by tuning the VCS compressor speed (Hz) for a surveillance system heat flow rate from 10 kW to 70 kW. The results from this study can be used to design a control strategy for the compressor. In a broader perspective, the two-part method and the results analysis presented can serve as a preliminary method for aircraft VCS control optimization studies.

Application of machine learning and grey Taguchi technique for the development and optimization of a natural fiber hybrid reinforced polymer composite for aircraft body manufacture

Abstract The rapid expansion of the air transport industry raises significant sustainability concerns due to its substantial carbon emissions and contribution to global climate change. These emissions are closely linked to fuel consumption, which in turn is influenced by the weight of materials used in aircraft systems. This study extensively applied machine learning tools for the optimization of natural fiber-reinforced composite material production parameters for aircraft body application. The Taguchi optimization technique was used to study the effect of sisal fibers, glass fibers, fiber length, and NaOH treatment concentration on the performance of the materials. Multi-objective optimization methods like the grey relational analysis and genetic algorithm (using the MATLAB programming interface) were employed to obtain the best combination of the studied factors for low fuel consumption (low carbon emission) and high-reliability structural applications of aircraft. The models developed from regressional analysis had high accuracy of prediction, with R-Square values all >80%. Optimization of the grey relational analysis of the developed composite using the genetic algorithm showed the best process parameter to achieve low weight material for aircraft application to be 40% sisal, 5% glass fiber at 35 mm fiber length, and 5% NaOH concentration with grey relational analysis at the highest possible level, which is unity.

Carbon fiber-reinforced, activated carbon-embedded copper oxide nanoparticles/epoxy hybrid composites for EMI shielding in aircraft applications

Carbon fiber-reinforced, activated carbon-embedded copper oxide nanoparticles/epoxy hybrid composites for EMI shielding in aircraft applications

Improved Adaptive Estimation Approach for Aircraft and Land Vehicle Applications

Improved Adaptive Estimation Approach for Aircraft and Land Vehicle Applications

Environmental control system (ECS) design approach for collective nuclear, biological, and chemical (NBC) protection in military aircraft: A review

This comprehensive review paper delves into Environmental Control System (ECS) design strategies tailored for collective Nuclear, Biological, and Chemical (NBC) protection in military aircraft, exploring key elements such as hardening, air-tight construction, and filtering within the framework of open-loop or closed-loop ECS configurations. Initially, the paper elucidates the NBC protection requirements stipulated in commonly applied regulations such as MIL-HDBK-516C, DEFSTAN, and EMACC, highlighting the imperative for ventilation air to be devoid of contaminants, as mandated by these regulations. Subsequently, the paper delineates the strategic framework for NBC defense in the military aerospace industry, emphasizing the principles of avoidance, protection, and decontamination. A comparative analysis between individual and collective protection strategies underscores the comprehensiveness of the latter, prompting a recommendation for ECS design approaches grounded in the principles of collective protection, namely hardening, air-tight construction, and filtering. Furthermore, the paper provides insights into the configurations of open-loop and partial closed-loop ECS, elucidating their architectures for NBC protection. A comparative evaluation of these configurations enables the identification of pertinent parameters crucial for informed selection. In conclusion, the paper posits that the partial closed-loop ECS configuration exhibits greater promise in delivering enhanced NBC protection compared to the open-loop configuration, particularly in military aircraft applications operating in NBC environments.

HTS Cable Design for Aircraft Application Considering Fault Conditions

HTS Cable Design for Aircraft Application Considering Fault Conditions

A Hybrid Phase-Frequency Control of Dual Active Bridge Converters for Hold-Up Time Extension in More Electric Aircrafts Applications

A Hybrid Phase-Frequency Control of Dual Active Bridge Converters for Hold-Up Time Extension in More Electric Aircrafts Applications

Finite Element Analysis of the Main Structure for a New Conceptual Aircraft Passenger Vertical Seat Design

Standing cabin is a new design concept of aircraft passenger cabin whereby passengers are transported in the standing position throughout flight as opposed to current seated position. An important element of this cabin concept is the design of the vertical seat to support the passengers, which has to be in compliance with requirements of aviation regulation. In commercial aircraft applications, weight of passenger seat is a significant factor that can affect flight performance of the aircraft. Meanwhile, the seat’s structure should have adequate strength to ensure proper safety provision to passengers. Hence weight and strength are potentially two conflicting design requirements for the vertical seat, and the optimum structural design should have the best compromise with regards to these two requirements. In this study, parametric study on primary structural design of the proposed vertical seat concept is done to obtain an optimized design that satisfies the strength requirements for safety of passengers without causing high penalty to the overall aircraft weight and performance. The simulation analysis for the main structures of the vertical seat design is conducted through finite element method using ABAQUS software. From the results of the analysis, main structural parts made from aluminium alloy with diameter 90 mm and thickness 3 mm are selected for the optimum vertical seat design. This standing seat design has also been shown to have adequate strength and can satisfy the safety regulation requirement without failure. The maximum stress on the seat’s structure under 9-g forward loading is found to be 147.5 MPa, which is lower than ultimate strength of aluminium. Moreover, the seat’s weight is estimated to be 9.5 kg and the maximum deflection of its main structures under forward 9-g loading is 28.42 mm. All in all, the stress analysis results highlight that the structural strength of the optimal vertical seat design can satisfy the requirements of the governing aviation regulations to provide safety to passengers.

Experimental study and simulations of hydrogen cooling effectiveness for aviation PEM fuel cells

Proton exchange membrane fuel cells (PEMFCs) are seen as one possible future means of driving the change towards a zero-emission society. In a civil aircraft, fuel cell systems can have multiple potential benefits, such as reduced noise, lowered emissions and higher fuel economy compared to jet aircraft. For controlling the fuel cell temperature, thermal management systems are required which can be optimized for aircraft applications regarding their weight and reliability. In this work, a simplified and light-weight thermal management system relying on hydrogen cooling is presented and analysed. To investigate the feasibility, a test rig and a three-dimensional, singular channel model in ANSYS Fluent were designed. Fuel cell temperature could be maintained within the set threshold in the model and the test rig, thus showing that controlling the fuel cell temperature via the hydrogen reactant flow is a viable alternative thermal management system. Results from the model indicate that both the hydrogen mass flow and hydrogen inlet temperature should be used to control the fuel cell temperature. Furthermore, operating the fuel cell at medium to low current densities is favourable for hydrogen cooling. Future studies will explore alternate flow field designs to facilitate thermal management system relying on hydrogen.

Out-of-plane compressive response of aluminum honeycomb sandwich panels: Adhesive geometry and bonding effects

Lightweight aluminum honeycomb sandwich panels are widely used in industrial engineering, particularly in aircraft applications. Due to their thin-walled nature, the honeycomb cell walls are especially susceptible to buckling under out-of-plane compressive loading, while the adhesive fillet that secures the honeycomb to the face-sheet remains intact. This paper investigates the effect of the adhesive geometry and bonding constraints on the out-of-plane compressive response through experimental, Finite Element (FE), and mathematical methods. A hybrid method accounting for adhesive bonding between the face-sheet and the cell walls, and different adhesive fillet geometries was proposed to predict strain onset and stress-strain relationships during densification. The resulting stress-strain curves predicted the energy absorbed by the panels to within 3.5 % of the experimental results. The widely used material model for honeycomb core does not account for densification and underpredicted the absorbed energy by 15.6 %. These findings emphasize the need for detailed adhesive analysis in the design of lightweight, thin-walled sandwich structures.

Light-induced motion of three-dimensional pendulum with liquid crystal elastomeric fiber

Liquid crystal elastomers (LCEs) typically exhibit slow deformation in response to environmental stimuli. However, recent studies have demonstrated that when LCE is reduced to a fiber form, it can undergo rapid and reversible contractions. This unique property allows LCE fibers to convert light energy into fast mechanical motion, enabling them to act as actuators that can swiftly flip the wings or lift an object. In this paper, we present a theoretical investigation of a three-dimensional pendulum constructed by a LCE fiber, which differs from the conventional pendulum with a fixed string length. The string length of the LCE pendulum is time-dependent and responsive to light radiation. We develop a nonlinear dynamic model based on Lagrangian mechanics and the photodynamic theory of LCE to study the effects of initial conditions, light intensity, radiation region, damping factor, and gravity on the characteristics of the three-dimensional pendulum. Our findings reveal the existence of three distinct modes of motion: static, light-excited self-oscillation, and light-excited self-rotation. We elucidate the mechanisms underlying these modes by investigating the time-dependent length of the string, the forces acting on the string, and the work done by light radiation during each period. The results and dynamic model presented in this paper provide valuable insights into light-driven motion structures and offer references for the design of soft robotics, energy harvesting devices, and wing-flapping micro aircraft applications based on smart soft materials.

Experimental Investigation of a Low-Temperature Three-Circuit Cooling System for an Electric Motor under Varying Loads

This study investigates a low-temperature three-circuit cooling system for a 55 kW industrial electric motor. The cooling system provides an increase of the power-to-dimension ratio by 63%, together with an improvement in motor performance. The three-circuit cooling system includes water cooling of the housing and stator and air-cooling of the motor’s interior. The test results show that the motor efficiency was maintained in the range between 92.5 and 94.5%, with respect to the motor’s power. With power increases up to 90 kW, a winding temperature of 67 °C was observed during three hours of operation. This advancement is particularly valuable for vehicles, ships, and aircraft applications, where maximizing power within limited space is crucial. An analysis of the experimental data showed that the cooling system operates at an average efficiency of 79.2%, indicating that roughly 20% of heat was accumulated in the rotor. This leads to a gradual temperature rise, particularly in the rotor, posing a risk of overheating and failure during motor overloads above 90 kW. Enhancing the cooling efficiency within the motor’s interior can be achieved by incorporating extra heat exchangers, implementing evaporative heat transfer, and employing water-cooling circuits at lower temperatures. This, in turn, can boost the electric motor’s power-to-dimension ratio.

High-temperature dielectric energy storage films with self-co-assembled hot-electron blocking nanocoatings

Polymer thin films operable under concurrent electric and thermal extremes represent critical building blocks of capacitive energy storage and electrical isolator for modern power and electronic systems with ever-increasing demands for power density and payload efficiency. However, polymer dielectrics are prone to fast aging under high fields due to hot electrons injected from electrodes. Especially, performance high-heat polymers such as polyimides with high aromaticity suffer fast aging induced by non-thermalized electrons even at moderate fields due to their intrinsically low bandgap and injection barrier. Herein, a facile, low-cost, and scalable interface-engineering approach utilizing the highly ordered organic/inorganic layered nanocoatings is reported, which serve as a retrofittable solution to break this design constraint. By probing the energetic modes of transport and aging at pre-breakdown field, we demonstrate that our 2D montmorillonite (MMT) self-co-assembly nanocoatings can effectively boost the dielectric properties of substrate polyimide (PI) film by suppressing the charge injection and shifting the fast mode of hot-electron aging to a slow, ultimately thermalized process. This aging-impeding scheme imparts PI films with an exceptional endurance capability (enhanced by 100 MV/m) and a 6× improved charge-discharge efficiency at an elevated temperature of 175 °C. The nanostructured interface engineering disclosed in this work thus opens a new pathway of boosting the performance of a spectrum of high-heat polymer dielectrics already commercially available in thin gauges of films for applications in zero-emission electric aircraft and renewable energy integration.

Design and Flight Qualification of a Flying Capacitor Multilevel Converter for Electric Aircraft Applications

Multilevel switched-capacitor converters, such as the flying capacitor multilevel (FCML) converter, offer high energy density and efficiency, over a wide voltage range, making them suitable for applications in electrified aircraft. However, concerns of reliability due to the increased number of active and passive components have limited the use of high-level count converters in aircraft applications. This work addresses the challenges of designing a high-level count converter with the goal of extremely high efficiency and power density, with maintained reliability and flight readiness. We present detailed component selection and design techniques to achieve this goal, along with a high-performance 28.2 kW/kg, 99.52% efficient high-voltage dc-dc step-up power converter for experimental validation. Finally, we demonstrate successful completion of critical flight qualification testing of the hardware prototype, including thermal, shock and vibration.

Toward Airframe Noise Reduction for Passenger Aircraft

Airframe noise is one of the main noise sources of the latest passenger aircraft during the approach phase. To demonstrate noise reduction technology based on unsteady Computational Fluid Dynamics (CFD) and wind tunnel tests, JAXA conducted flight tests using the JAXA Experimental Aircraft "Hisho" in 2016 and 2017 in cooperation with industries in Japan. The noise data obtained from flyover noise source measurements successfully showed consistent characteristics with the noise reduction designs for the flaps and the main landing gear. The noise measurement data from the flight test 2017 were used to validate the wind tunnel tests and CFD used in the design phase. Subsequently, the research activities proceeded towards the research and development targeting regional jet aircraft, aiming for practical application in passenger aircraft. This paper overviews these research activities toward developing airframe noise reduction technology for passenger aircraft.

Study on development of aircraft design theory

Nowadays, the aircraft has become a very important part of human life. The invention of the aircraft is a shining point in human civilization. During the development of aircraft, there have been significant changes in aircrafts appearance, power systems, design theories, and applications. In order to provide a clearer understanding of the development process of aircraft and lay the groundwork for future development of the aircraft, this article reviews the three important stages in the development of aircraft and elaborates on the development of aircraft from the perspectives of structural changes, theoretical updates, and applications. While introducing the development process, this article emphasizes the difficulties at each stage and the measures to solve them. In a hundred years of development, human beings have evolved from relying solely on the experience and imitation of birds in the early stages to developing and applying aerodynamics and then combining theory and practice to design.

Surface functionalization of carbon fiber by hydrothermally synthesized ZnO nanostructures for mechanical strengthening of polymer composites

AbstractIn this work, the effects of ZnO nanostructure‐surface functionalized carbon fibers has been examined along with their impacts on mechanical attributes of resulting hybrid carbon fiber reinforced polymer (CFRP) composites. The procedure involves hydrothermally generating ZnO nanostructures on carbon fibers. To generate hybrid composites, the modified carbon fiber fabric is then utilized as reinforcement in a matrix made of bisphenol‐A epoxy resin and polymer. The electron microscopy technique was employed to study development phenomenon of nanostructures on the fiber. According to the findings, lengthening the growth treatment and increasing seeding cycles improves the rate of ZnO formation. However, the results are not significantly impacted by the growth solution's concentration. The weight change analysis, X‐ray diffraction, Fourier transform infrared spectroscopy, UV‐spectroscopy, and energy dispersive spectroscopy all provide additional support for these conclusions. In comparison to plain CFRP composites, the developed hybrid CFRP composites tensile properties and impact resistance are significantly better. The ZnO‐modified CFRP composites exhibit improvements in elastic modulus, tensile strength, and in‐plane shear strength of up to 46.44%, 48.63%, and 20.79%, respectively. The hybrid composites' capacity to absorb impact energy also rises by 76%. Based on these results, the developed hybrid composites exhibit promising properties for applications in industries such as aircraft and automobile manufacturing. They offer high impact strength, high modulus, lightweight characteristics, and low void content, making them desirable materials for these industries.Highlights Controlled growth of vertically aligned ZnO nanostructures on fiber surface has been accomplished using hydrothermal method. Characteristics of CFRP composites such as tensile strength, elastic modulus, in‐plane shear strength, and impact energy absorption, were significantly enhanced on inclusion of ZnO. The developed hybrid composites offer cost‐effective solutions with improved mechanical properties. High impact strength and modulus make them suitable for applications in aircraft and automobile industries. Achieved exceptional morphological structure and enhanced surface‐to‐volume ratio.