Aircraft Cabin Research Articles

Numerical study on spray cooling of aircraft equipment cabin

With the increase in the number of aircraft onboard equipment and the sharp increase in heat dissipation power, the thermal control of cabin equipment has become one of the important issues restricting the development of high-speed aircraft technology. Spray cooling has the advantages of high cooling efficiency, simple cooling system structure, easy adjustment and control, etc. It is one of the most effective methods for thermal control of the aircraft equipment cabin. This work builds a simplified physical model of the aircraft equipment cabin, and improves the simulation method of the spray cooling of the equipment cabin. To test the accuracy of the simulation method, an experimental validation study was carried out. In the three-dimensional numerical simulation of cabin spray cooling, the structure characteristics of multi-nozzle spray droplet field, temperature field and flow field are addressed. It’s found that using multi-nozzle spray cooling for large-area and multi-surface equipment cabins is feasible, which can effectively control the temperature of most surfaces. However, for some slit areas, such as between adjacent equipment and between the equipment and the cabin, the temperature is relatively high due to the ineffective coverage of spray cooling. An improved method was applied to investigate the variation of temperature and pressure of the cabin during spray cooling. The study found that the pressure in the cabin can be flexibly controlled by adjusting the size of the exhaust hole of the cabin. The matching of the heating power of the cabin and the spray cooling capacity is an important guarantee condition for realizing the temperature and pressure control of the cabin. This study provides valuable reference data for engineers to design aircraft cabin cooling schemes.

A Comparative Study of a Hybrid Experimental–Statistical Energy Analysis Model with Advanced Transfer Path Analysis for Analyzing Interior Noise of a Tiltrotor Aircraft

The excessive noise present within an aircraft cabin during flight operations constitutes a notable origin of fatigue, stress, and communication impediments for both pilots and passengers. Ensuring the comfort, well-being, and safety of passengers and crew members necessitates the accurate anticipation of noise levels. This study concerns the computation of structure-borne noise levels within the cabin of a tiltrotor aircraft. This investigation employed two distinct methodologies: advanced transfer path analysis (ATPA) and statistical energy analysis (SEA). To assess the results obtained with the ATPA approach, the acquired outcomes were compared with empirically measured sound pressure levels during airplane mode operations. The contributions of air-borne and structure-borne noises were calculated with the ATPA methodology. On the other hand, the structure-borne noise was calculated with a hybrid experimental–SEA model with ACTRAN software, and its results were compared with those of the ATPA method. The results show a good agreement between these methods at high frequencies, while at low frequencies, certain adjustments or modifications to the SEA model are necessary to predict the noise levels.

Investigating the impact of gaspers on airborne disease transmission in an economy-class aircraft cabin with personalized displacement ventilation

Overhead gaspers provide directional fresh airflow, and thus affect the local airflow pattern and contaminant distribution. To investigate the impact of gaspers on airborne disease transmission in an aircraft cabin with a personalized displacement ventilation system, numerical calculations were conducted in a seven-row, single-aisle, fully occupied, economy-class aircraft cabin with the computational fluid dynamics (CFD) simulation method. We first investigated the impact of source gasper direction and flow rate on the airborne transmission near the contaminant source. We then investigated the protective effect of the receptor's gasper. For a source passenger's gasper, the direction and flow rate of the gasper flow either increased or decreased the air contaminant transmission to other passengers. Directing the source gasper to the abdomen with a medium flow rate performed best by reducing the receptors' mean exposure index by at least 45%, as this approach minimized the contaminant circulation in the cabin. Turning on a receptor passenger's gasper could be an effective strategy to protect the receptor, and the working mechanism was revealed. The gasper-induced jet flow entrained the surrounding air into the jet region, and the protective effect was related to the contaminant concentration at ceiling level. With a suitable gasper direction and flow rate, the gasper jet formed a virtual barrier between the source passenger and the receptor. When the contaminants were transported upwards to a receptor's breathing zone, turning on the receptor's gasper reduced the contaminant concentration, since the downward gasper jet altered the airflow pattern in front of the receptor.

Smarter Data Transfer Through Light-Fidelity Systems

The proliferation of wireless communication technologies has spurred the exploration of novel approaches to address the increasing demand for high-speed data transmission and alleviate the challenges posed by radio frequency-based systems. Li-Fi (Light Fidelity) has emerged as a promising paradigm by harnessing visible light to establish data communication. This research paper delves into the intricate mechanics, capabilities, and potential applications of Li-Fi technology. The underlying principles of Li-Fi involve the modulation of visible light using light-emitting diodes (LEDs) to transmit data in the form of binary signals. This modulation occurs at high speeds, beyond the perceptible range of the human eye, enabling the encoding and transmission of vast amounts of data. By capitalizing on the unexplored spectrum of visible light, Li-Fi not only offers remarkable data transfer rates but also addresses concerns related to electromagnetic interference, a constraint often encountered by radio frequency-based systems. The significance of Li-Fi extends to diverse domains, including indoor wireless communication, the Internet of Things (IoT), and intelligent lighting systems. In environments where radio frequency signals encounter limitations, such as aircraft cabins and healthcare facilities, Li-Fi presents a compelling solution by providing reliable connectivity. Moreover, the integration of data communication capabilities with existing illumination infrastructure has the potential to pave the way for energy-efficient smart environments, thereby aligning with contemporary sustainability objectives.

Model-based design and multidisciplinary optimization of complex system architectures in the aircraft cabin

The aviation industry is currently facing major challenges due to environmental and socio-economic trends toward sustainable and digitalized aviation. Revolutionary, more powerful and efficient technologies must be rapidly integrated into aircraft, while aircraft manufacturers must demonstrate the required safety. To support the implementation of new concepts, the DLR Institute of System Architectures in Aeronautics is researching methods for end-to-end digitalization from the preliminary design phase to assembly and production. In this context, Model-Based Systems Engineering (MBSE) and Multidisciplinary Design Optimization are important approaches for the development of complex systems. This paper presents a method for the end-to-end use of digital models for multidisciplinary optimization of system architectures. The Systems Modeling Language (SysML) is used to represent the system architecture. The focus is on the cabin and cabin systems, since they are highly coupled to other aircraft systems and have dynamic, customer-specific configuration requirements. The system architecture in SysML is instantiated and configured by the interface to the aircraft fuselage and cabin design parameter sets in the Common Parametric Configuration Schema. The subsequent coupling of the generated system architecture model with the cabin system design model developed in Matlab allows a multidisciplinary optimization of the system properties. A sensitivity analysis is performed using the Passenger Service Unit as an example. The effects of different cabin configurations on the system architecture are investigated and interdisciplinary synergies are identified and analyzed. The results of this analysis are discussed in this paper.

Discomfort estimation for aircraft cabin noise using linear regression and modified psychoacoustic annoyance approaches.

Appropriate sound quality models for noise-induced discomfort are necessary for a better acoustic comfort design in the aircraft cabin. This study investigates the acoustic discomfort in two large passenger aeroplanes (i.e., planes A and B). We recorded the noise at 21 positions in each aircraft cabin and selected 42 stimuli ranging from 72 to 81 dB(A) during the cruising flights. Twenty-four participants rated the noise discomfort by the absolute magnitude estimation method. The discomfort values in the middle section of the aircraft cabin are 10% points higher than in the front or rear section. The discomfort magnitude was dominated by loudness and influenced by roughness and sharpness. A multiple linear (MA) discomfort model was established, accounting for the relationship between the discomfort and sound quality metrics (i.e., loudness, sharpness, and roughness). The MA model estimated noise discomfort better than the Zwicker and other (i.e., More and Di) psychoacoustic annoyance (PA) models. We modified the coefficients of independent variables in the formulations of Zwicker, Di, and More PA models, respectively, according to the present experimental results. The correlation coefficients between the estimated and measured values of the modified models were at least 20% points higher than the original ones.

THE IMPACT OF AIRCRAFT CABIN DIGITALIZATION ON IMPROVING PASSENGER EXPERIENCE IN EGYPTAIR

This study aims to investigate the impact of aircraft cabin digitalization (smart electronically dimmable windows, intelligent seats, smart overhead bins, radio-frequency identification tags for luggage tracking, futuristic intelligent seats, and inflight virtual reality) on improving the inflight passenger experience in EgyptAir, as well as measuring passengers' interest in using digital cabins. Furthermore, exploring passengers’ intention to pay to use digital services, including futuristic intelligent seats, inflight virtual reality, and radio frequency identification tags for tracking luggage. To meet the research goals, a structured survey was designed and distributed among Egyptian frequent travelers in EgyptAir. A total of 311 complete surveys were collected and analyzed. Results indicated the high interest of Egyptian passengers in using the digital aircraft cabins in EgyptAir due to its significant impact on improving their inflight experience. Furthermore, analyses revealed the high intention of Egyptian passengers to pay to use inflight virtual reality and futuristic intelligent seats. However, they showed a moderate intention to pay to use radio frequency identification tags for tracking luggage.

A CFD-Based Design of S-Shaped Nozzle Attachment for Aircraft Cabin Gaspers

Cough has been the primary mode for transmitting airborne respiratory diseases as the droplets expelled are suspended in the air longer in closed environments like aircraft cabins. Air jets from personal gasper nozzles are studied using computational fluid dynamics (CFD) simulations to understand the flow pattern, which is of high velocity, very narrow, and susceptible to enhanced air mixing. An S-shaped nozzle attachment uses higher-order Bezier curves to spread the flow across the passenger’s face to form a shield to protect the breathing zone from foreign particles. The design of experiments theory, the Box – Behnken design, was employed to understand the influence of nozzle profile geometric parameters on the output criteria through CFD simulations. The numerical simulations were performed on the final design, which shows that the newly designed nozzle attachment can distribute the narrow jet from existing personal gasper nozzles into a curved air curtain across the passenger’s face.

RE-DESIGN TANGGA PESAWAT UNTUK LOADING DAN UNLOADING KURSI PADA PESAWAT AIRBUS 320 NEO DI PT BAT

PT. Batam Aero Technic which is a subsidiary of Lion Air airline that focuses on Maintenance, Repair and Overhaul (MRO) or maintenance of aircraft. One of the maintenance in the BAT hangar is the maintenance of the aircraft cabin section which is commonly called the Cabin Base Maintenance (CBM) Division. The CBM Division is responsible for the interior of the aircraft, starting from small to large scale repairs. In the initial observation, there was the biggest complaint of work posture of 66.67%, pain in the upper neck when lifting airplane seats manually and using stairs that did not fit properly. So it is important to design a tool to reduce musculoskeletal complaints. The aim of the research is to design ergonomic stairs using the EFD method to determine design specifications and meet user needs and anthropometric measurements with NBM. Then, a survey by distributing questionnaires to obtain the design parameters of the transportation equipment developed with the results of the unloading size with Dimension Platform 4,14 m x 404 m, Height Min 1 m | Max 4,5 m, Structure Materials Body and Frame : Structure Steel with Coating, Electrical Control Panel Specification Remote Control / Wireless, Control panel box, Motor 1.5 HP 380 volt 3 phase, Flow Rate 3.2 LPM/210 bar. Others Specification Included, Hydraulic Jack Mounting, Tire Wheel c/w steering towing, Aluminum platform layer Railing, Rubber Bumper, Manual Box, Safety Locking Devices, 2 sets of Rack Gear with Electric Solenoid Release. The design developed is valid according to user needs and according to the 5% significance level and is better than the prefix design due to a more ergonomic ladder position and faster loading/unloading seats.

Efficient solutions of preconditioned large‐scale systems for simulative aircraft cabin noise assessment

AbstractThe rising number of passengers transported by aircraft leads to more flight traffic, further increasing the environmental impact of the aviation sector. In order to combat the growing environmental impact, the Cluster of Excellence Sustainable and Energy Efficient Aviation of TU Braunschweig aims to advance research toward climate neutral aviation, especially with the design of newly developed aircraft. In the conscience of passengers, the focus is also shifted toward a healthy and comfortable travel experience. One of the main factors influencing these aspects is noise inside the aircraft cabin. A lower noise impact can help increase the technology acceptance and further push toward more sustainable airborne transport solutions. In order to assess cabin noise with moderate effort in an early design stage, simulative methods such as the finite element method (FEM) are deployed. These have the advantage of yielding important insights into the noise distribution inside the aircraft cabin without having to have a built prototype present. Since methods like the FEM are of a wave‐resolving nature, results contain high‐resolution wave propagation information of the sound waves, created, for example, by the excitation of the turbulent boundary layer on the aircraft's outer skin. Additionally, a direct auralization at seat positions is possible. More powerful computers have further improved the usage of models for an early design noise assessment. However, the more elaborate a model is, the more degrees of freedom (DOFs) it yields as final system of equations. Finally, since the FEM is of wave‐resolving nature and in order to depict sound waves accurately, a fine discretization of 10 nodes per frequency dependent wave length is needed. This leads to a massive increase in DOFs for higher frequencies and finally yielding a large‐scale model, which entails huge computational efforts. This makes the usage of adaptive grids very convenient. In this contribution, adaptive grids entail two main aspects: frequency and domain adaptive discretization. Since higher frequencies lead to shorter wavelengths and therefore finer mesh sizes, it is feasible to adaptively discretize the model in the frequency domain, while also adaptively discretizing the different domains of the models itself, because different materials lead to different wavelengths. However, the resulting system of equations might be ill‐posed. Therefore, this contribution aims to shed light on an efficient solving process of these adaptively discretized large‐scale models with preconditioning and adequate solver choice.

Emergency evacuation behavior characteristics classification of aircraft cabin passengers based on deep learning network model SMCNN-LSTM

Emergency evacuation behavior characteristics classification of aircraft cabin passengers based on deep learning network model SMCNN-LSTM

Discussion on the static-thermal test technology of aircraft

During the high-speed flight of the aircraft, the cabin body will bear aerodynamic loads, engine thrust loads, structural and equipment component mass inertial loads. At the same time, aerodynamic thermal loads will be generated due to high speed flight. With the development of hypersonic aircraft technology, the demand for multi-field coupling test is more and more common. Therefore, it is necessary to carry out the technical verification of the mechanics and thermal composite test on the ground to obtain the structural characteristics. In this paper, a certain type of aircraft cabin as the research object, carried out the research on the combined mechanical and thermal test technology. The results of this paper show that the displacement response of the cabin under the combined action of force and thermal load is consistent with the change trend of the force loading curve, and the force load has obvious influence on the displacement response of the cabin. The strain response is consistent with the trend of temperature curve, and thermal load has obvious influence on cabin deformation. Through this study, we can obtain the static-thermal test technology method, and provide the technical basis for the development of similar test technology.

Design and analysis of periodic acoustic metamaterial sound insulator using finite element method

In this article, a design of acoustic metamaterial containing Helmholtz resonators periodically embedded in a porous material is investigated for aerospace applications using the finite element method (FEM). The results obtained using the FEM are compared with the results of the theory, and the proposed transfer matrix method and good agreements are obtained. The transfer matrix method was combined with FEM calculations for two different termination conditions (plane wave radiation and rigid wall) in order to retrieve the equivalent matrix of the porous layer with the integrated periodic resonator. The equivalent matrix is then coupled analytically in series with others matrices. Finite element method studies are carried out on single and double wall configurations, and the effects of different resonator parameters and the air gap on the transmission loss are illustrated. The influences of the orientation of the neck opening and the resistivity of the porous material are also studied. Finite element method results for different incident angles are presented for single and double wall configurations. The proposed design can potentially be integrated into the panels of aircraft cabins in order to reduce the noise level at low frequencies inside the cabin.

High-resolution vibroacoustic characterization of DLR’s Falcon 2000LX ISTAR aircraft

In the framework of CleanSky2’s Airframe project DA9, engine tonal noise is a cooperation between Dassault Aviation and DLR. The project aims to enhance the understanding and mitigation of engine-related tonal noise in the aircraft cabin. The presented work was done to get an in-depth understanding of the vibroacoustic behavior of DLR’s Falcon 2000LX ISTAR aircraft. A two and a half weeks long vibroacoustic ground test was conducted utilizing artificial shaker excitation and operational engine excitation. The responses were measured using a roving grid of accelerometers at more than 1200 positions, meaning a subset of about 250 sensors were installed at every given time and then moved along the fuselage in a predetermined way to get a high-resolution measurement of aircrafts fuselage. The accelerometer data were than processed to show operational deflections shapes and calculate experimental structural intensity vector fields to analyze the energy transfer through the structure for optimized placement of active or passive counter measures. Specifically, the transport of tonal frequencies generated by the engines was analyzed.

Experimental Study on Individual and Group Evacuation of Passengers from an Aircraft Cabin in the Pitch/Roll State

Experimental Study on Individual and Group Evacuation of Passengers from an Aircraft Cabin in the Pitch/Roll State

CFD SIMULATION AND VALIDATION FOR MIXING VENTILATION SCALED-DOWN EMPTY AIRCRAFT CABIN USING OPENFOAM

An investigation into the spread of the COVID-19 virus within a confined space including an aircraft cabin is essential in order to find out the mechanism. However, this is time-consuming and limited in scope, so a computational fluid dynamics (CFD) simulation is used instead. Therefore, a prior study and an appropriate choice of turbulence model are required before the simulation. The main objective of this study is to validate and evaluate the results predicted by the Open Source Field Operation and Manipulation (OpenFOAM) software through comparison with the experimental data from the literature which was conducted using particle image velocimetry (PIV) measurement. Three different Reynolds-averaged Navier-Stokes turbulence models were selected; Re-normalisation Group k - ɛ (RNG), Realizable k - ɛ (RLZ) and Low Reynold Number (LRN) to simulate a mixing ventilation system of a scaled-down model of empty aircraft cabin. In the RNG and LRN model cases, a fairly large circulation flows were observed on the right and left sides of the model representing the passenger area. The results were also evaluated quantitatively using the factor of two of observations (FAC2) for the velocity components and turbulent kinetic energy (TKE) with root mean square error (RMSE) for the former and normalised mean square errors (NMSE) for the latter. The simulation results showed that RNG and LRN are capable of predicting the flow field well. However, for TKE prediction LRN performed better than RNG which concluded that LRN is the suitable turbulence model in simulating flow fields in investigated case.

Stability of SARS-CoV-2 on Commercial Aircraft Interior Surfaces with Implications for Effective Control Measures.

The COVID-19 pandemic from 2019 to 2022 devastated many aspects of life and the economy, with the commercial aviation industry being no exception. One of the major concerns during the pandemic was the degree to which the internal aircraft environment contributed to virus transmission between humans and, in particular, the stability of SARS-CoV-2 on contact surfaces in the aircraft cabin interior. In this study, the stability of various major strains of SARS-CoV-2 on interior aircraft surfaces was evaluated using the TCID50 assessment. In contrast to terrestrial materials, SARS-CoV-2 was naturally less stable on common contact points in the aircraft interior, and, over a 4 h time period, there was a 90% reduction in culturable virus. Antiviral and surface coatings were extremely effective at mitigating the persistence of the virus on surfaces; however, their benefit was diminished by regular cleaning and were ineffective after 56 days of regular use and cleaning. Finally, successive strains of SARS-CoV-2 have not evolved to be more resilient to survival on aircraft surfaces. We conclude that the mitigation strategies for SARS-CoV-2 on interior aircraft surfaces are more than sufficient, and epidemiological evidence over the past three years has not found that surface spread is a major route of transmission.

A Virtual Sensing Active Noise Control System Based on a Functional Link Neural Network for an Aircraft Seat Headrest

PurposeThe goal of this work is to propose a local Active Noise Control system for an aircraft seat’s headrest. This system should be able to extend the quiet zone beyond the physical microphones that can be placed behind the passenger’s head due to space constraints. Furthermore, the control algorithm should perform efficiently when non-linear phenomena exist during the sound propagation.MethodsA functional link neural network and a computationally efficient Multiple Input Multiple Output approach are used for the system’s implementation. The quiet zone is extended by linearly estimating the acoustic pressure in front of the headrest surface. The main novelty of this paper is the combination of these methods in an attempt to improve acoustic pressure attenuation performance, while keeping computational complexity low.ResultsThe proposed control algorithm has been evaluated through numerical simulations, including Finite Element Method and experimental tests at an aircraft cabin mock-up. The results show that for a real-world acoustic disturbance, a 10 dB reduction in sound pressure level was achieved 10 cm away from the headrest surface. In addition, the attenuation of some harmonics can reach 20 dB and in most cases is bigger than the linear FxLMS algorithm.ConclusionsTo summarize, it has been demonstrated that a multichannel functional link neural network using a simple virtual sensing technique can efficiently attenuate synthesized and real world acoustic disturbances captured in a tilt-rotor aircraft’s cabin. Finally, it can create an adequate quiet zone for gentle head movement while maintaining its stability.

Quantitative Microbial Risk Assessment of Contracting COVID-19 Derived from Measured and Simulated Aerosol Particle Transmission in Aircraft Cabins.

SARS-CoV-2 can be effectively transmitted between individuals located in close proximity to each other for extended durations. Aircraft provide such conditions. Although high attack rates during flights were reported, little was known about the risk levels of aerosol transmission of SARS-CoV-2 in aircraft cabins. The major objective was to estimate the risk of contracting COVID-19 from transmission of aerosol particles in aircraft cabins. In two single-aisle and one twin-aisle aircraft, dispersion of generated aerosol particles over a seven-row economy class cabin section was measured under cruise and taxi conditions and simulated with a computational fluid dynamic model under cruise conditions. Using the aerosol particle dispersion data, a quantitative microbial risk assessment was conducted for scenarios with an asymptomatic infectious person expelling aerosol particles by breathing and speaking. Effects of flight conditions were evaluated using generalized additive mixed models. Aerosol particle concentration decreased with increasing distance from the infectious person, and this decrease varied with direction. On a typical flight with an average shedder, estimated mean risk of contracting COVID-19 ranged from to . Risk increased to with a super shedder ( of cases) on a long flight. Risks increased with increasing flight duration: 2-23 cruise flights of typical duration and 2-10 flights of longer duration resulted in at least 1 case of COVID-19 due to onboard aerosol transmission by one average shedder, and in the case of one super shedder, at least 1 case in 1-3 flights of typical duration cruise and 1 flight of longer duration. Our findings indicate that the risk of contracting COVID-19 by aerosol transmission in an aircraft cabin is low, but it will not be zero. Testing before boarding may help reduce the chance of a (super)shedder boarding an aircraft and mask use further reduces aerosol transmission in the aircraft cabin. https://doi.org/10.1289/EHP11495.

An Approach for Linking Heterogenous and Domain‐Specific Models to Investigate Cabin System Variants

AbstractThis paper presents an approach to link heterogeneous and domain‐specific models. The background of this research is the complete investigation and comparison of cabin system variants, where many different aspects have to be represented. These include functional requirements, safety regulations, and geometric properties (e.g. installation space). However, these cannot always be validated or represented with just one model, as different levels of detail are required. Therefore, different discipline models have to be created, which in turn increases the complexity as a whole. Furthermore, the system to be represented by the models, such as the aircraft cabin, is already complex in itself. The many dependencies among each other and subsystems make it difficult to integrate new variants or technologies (e.g. liquid hydrogen) into the existing system architecture. The approach presented here therefore shows how the data and models of the different disciplines can interact with each other in order to be able to investigate variants holistically. This is demonstrated using the design of hatrack variants for a commercial aircraft.