Previous Issue
Volume 11, August
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
3.4
2.1
Journals
Aerospace
Volume 11
Issue 9
share announcement

Aerospace, Volume 11, Issue 9 (September 2024) – 22 articles

  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Reader to open them.
Order results
Result details
Section
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
24 pages, 1445 KiB  
Article
The Development of a Next-Generation Latticed Resistojet Thruster for CubeSats
by Daniel Turner, Robert Howie and Phil Bland
Aerospace 2024, 11(9), 714; https://doi.org/10.3390/aerospace11090714 (registering DOI) - 31 Aug 2024
Abstract
CubeSat and small satellite resistojet heat exchanger designs are based on conventional concepts that have been used since the 1960s, being primarily limited to helical or twisted tape heat exchangers. The design flexibility enabled by new additive manufacturing technologies is yet to be [...] Read more.
CubeSat and small satellite resistojet heat exchanger designs are based on conventional concepts that have been used since the 1960s, being primarily limited to helical or twisted tape heat exchangers. The design flexibility enabled by new additive manufacturing technologies is yet to be properly harnessed. This study introduces a novel resistojet concept that incorporates a highly miniaturized lattice structure as the heat exchanger. A conjugate heat transfer analysis determined that the lattice with a diamond unit cell had superior thermal performance compared to the same lattice with a gyroid unit cell and increased the heat transfer rate by up to 11% compared to a helical heat exchanger of the same volume. Performance testing of the prototype thruster with integral diamond lattice indicated that specific impulses of up to 94 s were possible with a 30-Watt heater using nitrous oxide as the propellant. The prototype thruster weighed only 22 g and demonstrated a 67% reduction in the power required to achieve the same specific impulse as previous nitrous oxide resistojets designed for the small satellite platform. The development of highly miniaturized latticed resistojets is shown to be feasible and highly attractive for CubeSats, where mass and power are of the utmost importance. Full article
14 pages, 676 KiB  
Article
Test Method for Single Satellite’s Inter-Satellite Link Pointing and Tracking via Ground Station
by Zhenqiang Hong, Xuxing Huang, Lifeng Yang, Zhiqiang Bian, Yong Yang and Shuang Li
Aerospace 2024, 11(9), 713; https://doi.org/10.3390/aerospace11090713 (registering DOI) - 31 Aug 2024
Abstract
Abstract: An inter-satellite link is a key technology that improves control accuracy, transmission efficiency, and autonomous capability of constellations. A satellite’s pointing and tracking abilities mainly determine the inter-satellite link’s performance, which should be validated through an in-orbit test. However, during the construction [...] Read more.
Abstract: An inter-satellite link is a key technology that improves control accuracy, transmission efficiency, and autonomous capability of constellations. A satellite’s pointing and tracking abilities mainly determine the inter-satellite link’s performance, which should be validated through an in-orbit test. However, during the construction of the constellation, the distribution of satellites does not satisfy the constraints of establishing the inter-satellite link. A test method for inter-satellite link pointing and tracking is developed with respect to a single satellite. A practical mission scenario for testing inter-satellite links’ performance is constructed. A virtual satellite is introduced as the target satellite to establish an inter-satellite link with the local satellite. The orbit of the virtual target satellite between two ground stations is characterized based on the Newton–Raphson method. By comparing the predicted and actual time differences between two ground stations receiving the signals from the local satellite, the inter-satellite link pointing and tracking abilities are evaluated independently. Numerical simulations verify the design of the virtual satellite. The single satellite test method for inter-satellite link pointing and tracking abilities is available. Full article
(This article belongs to the Special Issue Spacecraft Dynamics and Control (2nd Edition))
22 pages, 3346 KiB  
Article
An Improved Laplace Satellite Tracking Method Based on the Kalman Filter
by Shuang Cui, Jiang Li, Yang Yu, Ye Wang, Yuan Gao, Lei Zhang and Jiayu Chen
Aerospace 2024, 11(9), 712; https://doi.org/10.3390/aerospace11090712 (registering DOI) - 31 Aug 2024
Abstract
When photoelectric measuring equipment is used to track satellites, the extraction of the short-term or long-term target often fails because the target is weak, clouds block the target, and/or the sun’s angle is too small, resulting in the loss of the tracking target. [...] Read more.
When photoelectric measuring equipment is used to track satellites, the extraction of the short-term or long-term target often fails because the target is weak, clouds block the target, and/or the sun’s angle is too small, resulting in the loss of the tracking target. In this study, an improved Laplacian satellite tracking method based on the Kalman filter is proposed. Firstly, the improved Laplacian algorithm was used for the initial fitting of the equation of motion of a small amount of measurement data. Judgment of the validity and Kalman filtering was carried out on the current frame’s measurement data to calculate the optimal estimate of the current frame’s orbit data, and the accurate equation of motion was iteratively fitted to obtain high-precision data for predicting the satellite’s orbit frame by frame. Numerical tracking of the equipment was carried out. This method was experimentally validated on an actual optical measurement device. The test results showed that this method can make up for the frequent loss of short-term targets. Under the condition that the maximum deviation is less than 3”, the length of extrapolated data can be up to 30 s and the length of the measurement data was less than 30 s. This method may improve the stability of tracking equipment as well as the accuracy and integrity of the measurement data. Full article
(This article belongs to the Section Astronautics & Space Science)
27 pages, 3692 KiB  
Article
Handling Qualities Assessment and Discussion for Helicopter with Slung Load Systems Utilizing Various Sling Configurations
by Luofeng Wang and Renliang Chen
Aerospace 2024, 11(9), 711; https://doi.org/10.3390/aerospace11090711 (registering DOI) - 31 Aug 2024
Abstract
Sling configurations significantly influence the coupled dynamics of the helicopter with slung load system (HSLS), resulting in alterations to handling qualities (HQs) that remain inadequately understood. This study introduces a computer-oriented, generalized method for constructing the HSLS model with various sling configurations. To [...] Read more.
Sling configurations significantly influence the coupled dynamics of the helicopter with slung load system (HSLS), resulting in alterations to handling qualities (HQs) that remain inadequately understood. This study introduces a computer-oriented, generalized method for constructing the HSLS model with various sling configurations. To evaluate the HQs of 1-point, 2-point, and 4-point sling configurations, both the stability and response criteria outlined in ADS-33E and a newly proposed criterion for slung loads towards the updated ADS-33F were employed. Modal analysis was conducted to elucidate the coupled mechanisms of the HSLS under different sling configurations. The findings reveal that the dynamics of the main rotor can attenuate the lateral swing motions of the load in the 4-point sling configuration. While multiple-point sling configurations can enhance the helicopter’s bandwidth, they also amplify the magnitude notch in the helicopter’s response. Nevertheless, when a larger hook distance is employed, the notch frequency is sufficiently distant from the load swing bandwidth, leading to a reduced degradation in HQs. A 4-point configuration with lateral and longitudinal hook distances equal to twice the width and length of the slung load is recommended in practice to achieve sufficient swing stability and mitigate HQ degradation. Full article
(This article belongs to the Section Aeronautics)
19 pages, 12007 KiB  
Review
The Determination of Criticality for Ice Shapes Based on CCAR-25
by Xiong Huang, Shiru Qu, Heng Zhang, Feng Zhou and Yong Chen
Aerospace 2024, 11(9), 710; https://doi.org/10.3390/aerospace11090710 (registering DOI) - 31 Aug 2024
Abstract
Determining the criticality of ice shapes is a necessary condition for verifying compliance with icing airworthiness regulations. However, the clear, concise, and applicable criterion based on the geometric characteristics of ice shapes has not been clearly given out by current advisory circulars. To [...] Read more.
Determining the criticality of ice shapes is a necessary condition for verifying compliance with icing airworthiness regulations. However, the clear, concise, and applicable criterion based on the geometric characteristics of ice shapes has not been clearly given out by current advisory circulars. To address this problem, this paper summarizes aerodynamic performance items and recommended ice shapes the latest version of CCAR-25 and corresponding advisory circulars for a variety of flight phases, including takeoff, holding, en route, DTO, etc., instead of the single phase of holding in the previous research. Based on the geometric classification of the ice shapes, the dominant parameters of various ice shapes are clarified by the correlation between the geometric parameters and aerodynamic effects. The geometric parameters to determine the criticality of specific ice shapes are defined as the roughness height and range for the roughness ice and the total projection height in the direction of lift for the horn ice. On this basis, the detailed determination criterion of critical ice shape geometries corresponding to different flight phases and aircraft components is formulated, which will provide an operational selection methodology for determining the geometries of critical ice shapes at the airworthiness certification stage. Full article
(This article belongs to the Special Issue Deicing and Anti-Icing of Aircraft (Volume III))
►▼ Show Figures

Figure 1

25 pages, 1868 KiB  
Article
Fixed-Time Distributed Event-Triggered Cooperative Guidance Methods for Multiple Vehicles with Limited Communications to Achieve Simultaneous Arrival
by Zhenzhen Gu, Xugang Wang and Zhongyuan Wang
Aerospace 2024, 11(9), 709; https://doi.org/10.3390/aerospace11090709 (registering DOI) - 31 Aug 2024
Viewed by 50
Abstract
Aiming at the salvo-attack problem of multiple missiles, a distributed cooperative guidance law based on the event-triggered mechanism is proposed, which enables missiles with large differences in spatial location and velocity to achieve simultaneous attacks with only a few dozen information exchanges. It [...] Read more.
Aiming at the salvo-attack problem of multiple missiles, a distributed cooperative guidance law based on the event-triggered mechanism is proposed, which enables missiles with large differences in spatial location and velocity to achieve simultaneous attacks with only a few dozen information exchanges. It effectively reduces the generation of control commands and communication frequency, thereby reducing channel load and improving communication efficiency and reliability. Compared to traditional periodic sampling communication, the number of communications has been reduced by over 90%. The guidance process is divided into two stages. The first stage is the cooperative guidance stage, where missiles achieve consensus of the time-to-go estimates through information exchange. In this stage, each missile is designed with an event-triggered function based on its own state error, and the missile only updates and transmits its information in the communication network when the error meets the set threshold, effectively reducing the occupancy rate of missile-borne resources during the cooperation process. The second stage is the independent guidance stage, where missiles can hit the target simultaneously while keeping the communication network silent. This is achieved by ensuring that the time-to-go estimates of missiles can represent the real time-to-go after achieving consensus. By the design of the two-stage guidance law and the replacement of the event-triggered function, the cooperative guidance system can be ensured to remain stable in scenarios where the leader missile is present and destroyed, and this excludes Zeno behavior. The stability of the cooperative guidance law is rigorously proved by algebraic graph theory, matrix theory, and the Lyapunov method. Finally, the numerical simulation results demonstrate the validity of the algorithm and the correctness of the stability analysis. Full article
(This article belongs to the Section Aeronautics)
22 pages, 2631 KiB  
Article
Damage Detection and Localization Methodology Based on Strain Measurements and Finite Element Analysis: Structural Health Monitoring in the Context of Industry 4.0
by Andrés R. Herrera, Joham Alvarez, Jaime Restrepo, Camilo Herrera, Sven Rodríguez, Carlos A. Escobar, Rafael E. Vásquez and Julián Sierra-Pérez
Aerospace 2024, 11(9), 708; https://doi.org/10.3390/aerospace11090708 (registering DOI) - 30 Aug 2024
Viewed by 122
Abstract
This paper investigates the integration of Structural Health Monitoring (SHM) within the frame of Industry 4.0 (I4.0) technologies, highlighting the potential for intelligent infrastructure management through the utilization of big data analytics, machine learning (ML), and the Internet of Things (IoT). This study [...] Read more.
This paper investigates the integration of Structural Health Monitoring (SHM) within the frame of Industry 4.0 (I4.0) technologies, highlighting the potential for intelligent infrastructure management through the utilization of big data analytics, machine learning (ML), and the Internet of Things (IoT). This study presents a success case focused on a novel SHM methodology for detecting and locating damages in metallic aircraft structures, employing dimensional reduction techniques such as Principal Component Analysis (PCA). By analyzing strain data collected from a network of sensors and comparing it to a baseline pristine condition, the methodology aims to identify subtle changes in local strain distribution indicative of damage. Through extensive Finite Element Analysis (FEA) simulations and a PCA contribution analysis, the research explores the influence of various factors on damage detection, including sensor placement, noise levels, and damage size and type. The findings demonstrate the effectiveness of the proposed methodology in detecting cracks and holes as small as 2 mm in length, showcasing the potential for early damage identification and targeted interventions in diverse sectors such as aerospace, civil engineering, and manufacturing. Ultimately, this paper underscores the synergistic relationship between SHM and I4.0, paving the way for a future of intelligent, resilient, and sustainable infrastructure. Full article
(This article belongs to the Special Issue Aircraft Structural Health Monitoring and Digital Twin)
23 pages, 8690 KiB  
Article
Assessment of Turbulence Models for Cylinder Flow Aeroacoustics
by Xiao Wang, Shanti Bhushan, Adrian Sescu, Edward Luke, Bukhari Manshoor and Yuji Hattori
Aerospace 2024, 11(9), 707; https://doi.org/10.3390/aerospace11090707 - 30 Aug 2024
Viewed by 228
Abstract
Numerical simulations are performed for flows over a circular cylinder at a Reynolds number ranging from 150 to 5000, and Mach number of 0.2, to assess the predictive capability of URANS and hybrid RANS/LES for acoustic waves generation and propagation. Complementary direct numerical [...] Read more.
Numerical simulations are performed for flows over a circular cylinder at a Reynolds number ranging from 150 to 5000, and Mach number of 0.2, to assess the predictive capability of URANS and hybrid RANS/LES for acoustic waves generation and propagation. Complementary direct numerical simulations (DNS) are performed to generate validation datasets and to provide more insight into the problem. DNS predictions show that noise induced by the vortex shedding is radiated primarily at a 90-degree angle with respect to the wake direction and dictates the dominant frequency of the sound pressure waves. Turbulence dominates the noise in the near-field wake, resulting in a broadband pressure spectrum. URANS both underpredicts and overpredicts the noise levels in the wake region and in the direction normal to the freestream flow, respectively, which is attributed to its inability to accurately predict the turbulent kinetic energy content. Hybrid RANS/LES computations, using a second-order low-dissipation optimization-based gradient reconstruction scheme on a grid that is three times coarser than the DNS, provide an accurate prediction of the far-field noise levels, except in the wake region, where they are overpredictive. Full article
(This article belongs to the Special Issue New Developments in Aeroacoustics Research: From Fundamentals to Applications)
►▼ Show Figures

Figure 1

22 pages, 9496 KiB  
Article
Reinforcement Learning-Based Pose Coordination Planning Capture Strategy for Space Non-Cooperative Targets
by Zhaotao Peng and Chen Wang
Aerospace 2024, 11(9), 706; https://doi.org/10.3390/aerospace11090706 - 29 Aug 2024
Viewed by 284
Abstract
During the process of capturing non-cooperative targets in space, space robots have strict constraints on the position and orientation of the end-effector. Traditional methods typically focus only on the position control of the end-effector, making it difficult to simultaneously satisfy the precise requirements [...] Read more.
During the process of capturing non-cooperative targets in space, space robots have strict constraints on the position and orientation of the end-effector. Traditional methods typically focus only on the position control of the end-effector, making it difficult to simultaneously satisfy the precise requirements for both the capture position and posture, which can lead to failed or unstable grasping actions. To address this issue, this paper proposes a reinforcement learning-based capture strategy learning method combined with posture planning. First, the structural models and dynamic models of the capture mechanism are constructed. Then, an end-to-end decision control model based on the Optimistic Actor–Critic (OAC) algorithm and integrated with a capture posture planning module is designed. This allows the strategy learning process to reasonably plan the posture of the end-effector to adapt to the complex constraints of the target capture task. Finally, a simulation test environment is established on the Mujoco platform, and training and validation are conducted. The simulation results demonstrate that the model can effectively approach and capture multiple targets with different postures, verifying the effectiveness of the proposed method. Full article
(This article belongs to the Special Issue Space Mechanisms and Robots)
►▼ Show Figures

Figure 1

37 pages, 4159 KiB  
Article
Runway Safety Assistant Foreseeing Excursions: Calculating Means
by Georgios Alogdianakis, Ioannis Katsidimas, Athanasios Kotzakolios, Anastasios Plioutsias and Vassilis Kostopoulos
Aerospace 2024, 11(9), 705; https://doi.org/10.3390/aerospace11090705 - 29 Aug 2024
Viewed by 263
Abstract
Runway Safety Assistant Foreseeing Excursions (RUNSAFE) is a complete embedded system solution, that predicts a potential runway overrun of a civil aviation aircraft during takeoff and landing. This work examines the feasibility of such a system, through the algorithms and computations that predict [...] Read more.
Runway Safety Assistant Foreseeing Excursions (RUNSAFE) is a complete embedded system solution, that predicts a potential runway overrun of a civil aviation aircraft during takeoff and landing. This work examines the feasibility of such a system, through the algorithms and computations that predict the overruns. The system executes both static and dynamic calculations, with the former being dependent on and the latter independent to the user’s inputs. Their outcomes and the runway’s length are compared in real time to assess if the process will end up in an overrun. All inputs are specifically selected to either be available to the pilots or be retrieved from the existing avionics systems of the cockpit. A performance evaluation is conducted on both static and dynamic calculations, and metrics unveil the accuracy of the predictions and the time needed to converge to a reliable result. The solution is adapted for a Boeing 737-800 aircraft with CFM56-7B engines, but the calculations also apply for similar aircraft equipped with tricycle landing gear and turbofan engines, namely the whole Boeing 737 family, the Airbus A320 family, etc. The system is aligned with current standards and certification specifications, where applicable. Full article
(This article belongs to the Special Issue Overall Aircraft Design for New Airframe Technologies, New Energy Systems and New Operations)
►▼ Show Figures

Figure 1

13 pages, 9449 KiB  
Article
Research, Analysis, and Improvement of Unmanned Aerial Vehicle Path Planning Algorithms in Urban Ultra-Low Altitude Airspace
by Jianwei Gao and Weijun Pan
Aerospace 2024, 11(9), 704; https://doi.org/10.3390/aerospace11090704 - 28 Aug 2024
Viewed by 296
Abstract
Urban ultra-low altitude airspace (ULAA) presents unique challenges for unmanned aerial vehicle (UAV) path planning due to high building density and regulatory constraints. This study analyzes and improves classical path planning algorithms for UAVs in ULAA. Experiments were conducted using A*, RRT, RRT*, [...] Read more.
Urban ultra-low altitude airspace (ULAA) presents unique challenges for unmanned aerial vehicle (UAV) path planning due to high building density and regulatory constraints. This study analyzes and improves classical path planning algorithms for UAVs in ULAA. Experiments were conducted using A*, RRT, RRT*, and artificial potential field (APF) methods in a simulated environment based on building data from Chengdu City, China. Results show that traditional algorithms struggle in dense obstacle environments, particularly APF due to local minima issues. Enhancements were proposed: a density-aware heuristic for A*, random perturbation for APF, and a hybrid optimization strategy for RRT*. These modifications improved computation time, path length, and obstacle avoidance. The study provides insights into the limitations of classical algorithms and suggests enhancements for more effective UAV path planning in urban environments. Full article
(This article belongs to the Special Issue Advances in Air Traffic and Airspace Control and Management (2nd Edition))
►▼ Show Figures

Figure 1

22 pages, 3818 KiB  
Article
A Peak-Finding Siamese Convolutional Neural Network (PF-SCNN) for Aero-Engine Hot Jet FT-IR Spectrum Classification
by Shuhan Du, Wei Han, Zhenping Kang, Fengkun Luo, Yurong Liao and Zhaoming Li
Aerospace 2024, 11(9), 703; https://doi.org/10.3390/aerospace11090703 - 28 Aug 2024
Viewed by 234
Abstract
Aiming at solving difficulties related to aero-engine classification and identification, two telemetry Fourier transform infrared spectrometers are utilized to measure the infrared spectra of six types of aero-engine hot jets, and create a spectral data set, which is divided into a training set [...] Read more.
Aiming at solving difficulties related to aero-engine classification and identification, two telemetry Fourier transform infrared spectrometers are utilized to measure the infrared spectra of six types of aero-engine hot jets, and create a spectral data set, which is divided into a training set (80%), a validation set (10%), and a prediction set (10%). A peak-finding Siamese convolutional neural network (PF-SCNN) is used to match and classify the spectral data. During the training stage, the Siamese convolutional neural network (SCNN) is designed to extract spectral features and calculate the distance similarity. In order to improve the efficiency of the SCNN, a peak-finding method is introduced to extract the spectral peaks, which are used to train the model instead of the original spectral data. During the prediction stage, the trained model is used to calculate the similarity between the prediction set and the combined set of the training set and validation set, and the label of the most similar training data in each prediction set is used as the prediction label. The performance measures of the classification results include accuracy, precision, recall, confusion matrix, and F1-score. The experimental results show that the PF-SCNN can achieve a high classification accuracy rate of 99% and can complete the task of classifying the infrared spectra of aero-engine hot jets. Full article
(This article belongs to the Special Issue Machine Learning for Aeronautics (2nd Edition))
►▼ Show Figures

Figure 1

26 pages, 3780 KiB  
Article
Open-Source Data Formalization through Model-Based Systems Engineering for Concurrent Preliminary Design of CubeSats
by Giacomo Luccisano, Sophia Salas Cordero, Thibault Gateau and Nicole Viola
Aerospace 2024, 11(9), 702; https://doi.org/10.3390/aerospace11090702 - 27 Aug 2024
Viewed by 320
Abstract
Market trends in the space sector suggest a notable increase in satellite operations and market value for the coming decade. In parallel, there has been a shift in the industrial and academic sectors from traditional Document-Based System Engineering to Model-based systems engineering (MBSE) [...] Read more.
Market trends in the space sector suggest a notable increase in satellite operations and market value for the coming decade. In parallel, there has been a shift in the industrial and academic sectors from traditional Document-Based System Engineering to Model-based systems engineering (MBSE) combined with Concurrent engineering (CE) practices. Due to growing demands, the drivers behind this change have been the need for quicker and more cost-effective design processes. A key challenge in this transition remains to determine how to effectively formalize and exchange data during all design stages and across all discipline-specific tools; as representing systems through models can be a complex endeavor. For instance, during the Preliminary design (PD) phase, the integration of system models with external mathematical models for simulations, analyses, and system budgeting is crucial. The introduction of CubeSats and their standard has partly addressed the question of standardization and has aided in reducing overall development time and costs in the space sector. Nevertheless, questions about how to successfully exchange data endure. This paper focuses on formalizing a CubeSat model for use across various stages of the PD phase. The entire process is conducted with the exclusive use of open-source tools, to facilitate the transparency of data integration across the PD phases, and the overall life cycle of a CubeSat. The paper has two primary outcomes: (i) developing a generic CubeSat model using Systems modeling language (SysML) that includes data storage and visualization through the application of Unified modeling language (UML) stereotypes, streamlining in parallel information exchange for integration with various simulation and analysis tools; (ii) creating an end-to-end use case scenario within the Nanostar software suite (NSS), an open-source framework designed to streamline data exchange across different software during CE sessions. A case study from a theoretical academic space mission concept is presented as the illustration of how to utilize the proposed formalization, and it serves as well as a preliminary validation of the proposed formalization. The proposed formalization positions the CubeSat SysML model as the central data source throughout the design process. It also supports automated trade-off analyses by combining the benefits of SysML with effective data instantiating across all PD study phases. Full article
(This article belongs to the Special Issue Space Systems Preliminary Design)
►▼ Show Figures

Figure 1

20 pages, 15423 KiB  
Article
Numerical Study on the Influence of Inlet Turbulence Intensity on Turbine Cascades
by Xuan Wu, Yanfeng Zhang, Junqiang Zhu and Xingen Lu
Aerospace 2024, 11(9), 701; https://doi.org/10.3390/aerospace11090701 - 27 Aug 2024
Viewed by 318
Abstract
The turbulence intensity of the high-pressure turbine inlet plays an important role in the development of secondary flow and boundary layer evolution in the turbine passage. Unfortunately, current research often overlooks the coupling effect between boundary layer separation and endwall secondary flow, and [...] Read more.
The turbulence intensity of the high-pressure turbine inlet plays an important role in the development of secondary flow and boundary layer evolution in the turbine passage. Unfortunately, current research often overlooks the coupling effect between boundary layer separation and endwall secondary flow, and lacks comprehensive exploration of loss variation. To complement existing research, this study utilizes numerical simulation techniques to investigate the evolution of the boundary layer and secondary flow in high-pressure turbine cascades under varying turbulence intensities, with experimental research results as the basis. Furthermore, the relationship between profile loss and endwall secondary flow loss is analyzed. The research results indicate that higher turbulence intensity can enhance the anti-separation ability of the boundary layer, thereby reducing the blade profile loss caused by separation in the boundary layer. However, higher turbulence intensities (Tu) enhance the development of secondary flow within the cascade, leading to a significant increase in secondary flow losses. Q-criterion methods are employed to display the vortex structures within the passage, while loss decomposition is leveraged to uncover the variations of different losses under different turbulence intensities (Tu of 1% and 6%).With the exception of a minor decrease in total pressure loss (Yp) when Tu increases from 1% to 2%, Yp demonstrates a substantial increase in all other cases with increasing Tu. Additionally, this study explains why the loss of high-pressure turbine cascades shows a trend of first increasing and then decreasing with the increase in inlet turbulence intensity. Full article
►▼ Show Figures

Figure 1

20 pages, 5862 KiB  
Article
Optimization of Pyroshock Test Conditions for Aerospace Components to Enhance Repeatability by Genetic Algorithms
by Wonki Bae and Junhong Park
Aerospace 2024, 11(9), 700; https://doi.org/10.3390/aerospace11090700 - 26 Aug 2024
Viewed by 253
Abstract
Electronic components assembled in satellites should be able to withstand the vibration, noise, and impact loads generated by space vehicles during launch. To simulate the impact loading in a laboratory environment, a pyroshock test simulates an impact load resulting from explosions during the [...] Read more.
Electronic components assembled in satellites should be able to withstand the vibration, noise, and impact loads generated by space vehicles during launch. To simulate the impact loading in a laboratory environment, a pyroshock test simulates an impact load resulting from explosions during the stage and pairing separation of launch vehicles, which imposes significant stress on the components, potentially leading to failures and damage. To ensure component reliability before the flight model (FM) stage, where components are mounted on the actual launch vehicle and sent into orbit, a pyroshock test is conducted during the qualification model (QM) stage using identical parts and specifications. This process involves measurements of the acceleration induced by pyroshock to calculate the shock response spectrum (SRS) and evaluate the components’ reliability against the required SRS to confirm their ability to endure the shock and operate normally in post-tests. The aerospace developer determines the SRS requirements based on the space launch vehicle and the installation location of the electronic components. Configuring a suitable pyroshock test to meet these requirements typically involves extensive trial and error. This study aims to minimize such trial and error by examination of SRS changes through a numerical approach by table structural vibration analysis. The structure is subjected to in-plane impacts using a steel ball via a pendulum method. Various SRS profiles are calculated by test factors such as the weight of the steel ball, the pendulum angle, and the installation position of the test specimen. Furthermore, a genetic algorithm is utilized to derive the optimal test conditions that satisfy the required SRS. An automated pyroshock test system is developed to enhance repeatability and reduce human errors. Full article
►▼ Show Figures

Figure 1

28 pages, 90455 KiB  
Article
Lessons Learnt from the Simulations of Aero-Engine Ground Vortex
by Wenqiang Zhang, Tao Yang, Jun Shen and Qiangqiang Sun
Aerospace 2024, 11(9), 699; https://doi.org/10.3390/aerospace11090699 - 26 Aug 2024
Viewed by 284
Abstract
With the startup of the aero-engine, the ground vortex is formed between the ground and the engine intake. The ground vortex leads to total pressure and swirl distortion, which reduces the performance of the engine. The inhalation of the dust and debris through [...] Read more.
With the startup of the aero-engine, the ground vortex is formed between the ground and the engine intake. The ground vortex leads to total pressure and swirl distortion, which reduces the performance of the engine. The inhalation of the dust and debris through a ground vortex can erode the fan blade, block the seals and degrade turbine cooling performance. As the diameter of the modern fan blade becomes larger, the clearance between the intake lip and the ground surface is smaller, which enhances the strength of the ground vortex. Though considerable numerical studies have been conducted with the predictions of the ground vortex, it is noted that the accurate simulation of the ground vortex is still a tough task. This paper presents authors’ simulation work of the ground vortex into an intake model with different crosswind speeds. This paper tackles the challenge with a parametric study to provide useful guidelines on how to obtain a good match with the experimental data. The influence of the mesh density, performance of different turbulence models and how the boundary layer thickness affects the prediction results are conducted and analysed. The detailed structure of the flow field with ground vortex is presented, which can shed light on the experimental observations. A number of suggestions are presented that can pave the road to the accurate flow field simulations with strong vorticities. Full article
►▼ Show Figures

Figure 1

14 pages, 2235 KiB  
Article
An Endurance Equation for Hybrid-Electric Aircraft
by Aman Batra, Reiko Raute and Robert Camilleri
Aerospace 2024, 11(9), 698; https://doi.org/10.3390/aerospace11090698 - 26 Aug 2024
Viewed by 305
Abstract
This paper introduces a new endurance equation for a hybrid-electric aircraft. This research follows the derivation of a range equation for a hybrid-electric aircraft case using constant power split that was carried out by authors in their earlier work. Thus, the derivation of [...] Read more.
This paper introduces a new endurance equation for a hybrid-electric aircraft. This research follows the derivation of a range equation for a hybrid-electric aircraft case using constant power split that was carried out by authors in their earlier work. Thus, the derivation of the endurance equation maintains the use of efficiency-based degree of hybridization (φ) used in the earlier research. For coherence, the paper also uses the same case study to assess endurance values over a range of battery energy density values and degree of hybridization (φ) values. Results show that any aircraft design has an Energy Density Threshold (EDT) value, before which the endurance of the aircraft reduces with an increase in the degree of hybridization values. Conversely, once EDT is exceeded, the endurance of the aircraft enhances with the increase in the degree of hybridization values. The EDT values are specific to the aircraft type, its specifications and key design parameters. Full article
(This article belongs to the Special Issue Electric Machines for Electrified Aircraft Propulsion)
►▼ Show Figures

Figure 1

20 pages, 6592 KiB  
Article
Multiscale Modeling of Plasma-Assisted Non-Premixed Microcombustion
by Giacomo Cinieri, Ghazanfar Mehdi and Maria Grazia De Giorgi
Aerospace 2024, 11(9), 697; https://doi.org/10.3390/aerospace11090697 - 26 Aug 2024
Viewed by 345
Abstract
This work explores microcombustion technologies enhanced by plasma-assisted combustion, focusing on a novel simulation model for a Y-shaped device with a non-premixed hydrogen-air mixture. The simulation integrates the ZDPlasKin toolbox to determine plasma-produced species concentrations to Particle-In-Cell with Monte Carlo Collision analysis for [...] Read more.
This work explores microcombustion technologies enhanced by plasma-assisted combustion, focusing on a novel simulation model for a Y-shaped device with a non-premixed hydrogen-air mixture. The simulation integrates the ZDPlasKin toolbox to determine plasma-produced species concentrations to Particle-In-Cell with Monte Carlo Collision analysis for momentum and power density effects. The study details an FE-DBD plasma actuator operating under a sinusoidal voltage from 150 to 325 V peak-to-peak and a 162.5 V DC bias. At potentials below 250 V, no hydrogen dissociation occurs. The equivalence ratio fitting curve for radical species is incorporated into the plasma domain, ensuring local composition accuracy. Among the main radical species produced, H reaches a maximum mass fraction of 8% and OH reaches 1%. For an equivalence ratio of 0.5, the maximum temperature reached 2238 K due to kinetic and joule heating contributions. With plasma actuation with radicals in play, the temperature increased to 2832 K, and with complete plasma actuation, it further rose to 2918.45 K. Without plasma actuation, the temperature remained at 300 K, reflecting ambient conditions and no combustion phenomena. At lower equivalence ratios, temperatures in the plasma area consistently remained around 2900 K. With reduced thermal power, the flame region decreased, and at Φ = 0.1, the hot region was confined primarily to the plasma area, indicating a potential blow-off limit. The model aligns with experimental data and introduces relevant functionalities for modeling plasma interactions within microcombustors, providing a foundation for future validation and numerical models in plasma-assisted microcombustion applications. Full article
►▼ Show Figures

Figure 1

3 pages, 147 KiB  
Editorial
Special Issue “Gust Influences on Aerospace”
by Zhenlong Wu and Michael Hölling
Aerospace 2024, 11(9), 696; https://doi.org/10.3390/aerospace11090696 - 26 Aug 2024
Viewed by 275
Abstract
An important prerequisite for the design, assessment, and certification of aircraft, their propulsion systems, and associated control systems is a quantitative specification of the environment in which the aircraft are intended to operate [...] Full article
(This article belongs to the Special Issue Gust Influences on Aerospace)
12 pages, 5873 KiB  
Article
Validation of Experimental Data for the Application of the Magnesium Alloy “Elektron 43”
by Michele Guida
Aerospace 2024, 11(9), 695; https://doi.org/10.3390/aerospace11090695 - 25 Aug 2024
Viewed by 349
Abstract
The behaviour of a structural component, such as the spreader installed on an aeroplane passenger seat made of the magnesium alloy Elektron® 43, is evaluated under a variety of load conditions. The purpose of this research project is to considerably reduce weight [...] Read more.
The behaviour of a structural component, such as the spreader installed on an aeroplane passenger seat made of the magnesium alloy Elektron® 43, is evaluated under a variety of load conditions. The purpose of this research project is to considerably reduce weight by employing the new alloy while keeping the strength and ductility necessary to meet the dynamic standards for both the 16 g forward and 14 g downward tests. A comprehensive campaign of static and dynamic testing on coupons was conducted to characterise the mechanical behaviour of the E43 magnesium alloy, from quasi-static to dynamic loading, and across a wide range of deformation rates. The elastic–plastic and strain rate sensitive material model of E43 is then calibrated using an FEA approach and LS-DYNA software, utilising stress–strain curves and properties determined from standardised experimental tensile and compression trials at varied strain rates. Finally, this material model was used to perform a finite element structural study of a major component of an aeroplane seat built using Elektron® 43 under typical in-flight stresses. Full article
(This article belongs to the Special Issue Advanced Aerospace Composite Materials and Smart Structures)
►▼ Show Figures

Figure 1

21 pages, 3319 KiB  
Article
Thermo-Mechanical Jitter in Slender Space Structures: A Simplified Modeling Approach
by Maurizio Parisse and Federica Angeletti
Aerospace 2024, 11(9), 694; https://doi.org/10.3390/aerospace11090694 - 25 Aug 2024
Viewed by 329
Abstract
Thermally induced vibrations usually affect spacecraft equipped with light and slender appendages such as booms, antennas or solar panels. This phenomenon occurs when a thermal shock, resulting from the sudden cooling and warming phases at the entrance and exit from eclipses, triggers mechanical [...] Read more.
Thermally induced vibrations usually affect spacecraft equipped with light and slender appendages such as booms, antennas or solar panels. This phenomenon occurs when a thermal shock, resulting from the sudden cooling and warming phases at the entrance and exit from eclipses, triggers mechanical vibrations. The study proposed hereafter concerns the modeling and prediction of jitter of thermal origin in a long and thin plate with a sun-pointing attitude in geostationary orbit. The system’s temperature and dynamics are described by a set of equations expressing the two-way coupling between the thermal bending moment and the shape of the panel. The structure is discretized and reduced to a one-degree-of-freedom simplified model able to identify a mechanism of thermal pumping that could lead to instability. Finally, the results of the analysis are compared with those obtained with a more accurate FEM modelization. Full article
(This article belongs to the Special Issue Advanced Spacecraft/Satellite Technologies)
►▼ Show Figures

Figure 1

18 pages, 9114 KiB  
Article
A Physical and Spectroscopic Survey of the Lunar South Pole with the Galileo Telescope of the Asiago Astrophysical Observatory
by Nicolò Trabacchin, Paolo Ochner and Giacomo Colombatti
Aerospace 2024, 11(9), 693; https://doi.org/10.3390/aerospace11090693 - 23 Aug 2024
Viewed by 319
Abstract
In recent years, interest in the Moon has grown exponentially, thanks mainly to space programs with strong international cooperation, such as the NASA Artemis program. Several scientific committees have identified the lunar south pole as the region of greatest interest for building a [...] Read more.
In recent years, interest in the Moon has grown exponentially, thanks mainly to space programs with strong international cooperation, such as the NASA Artemis program. Several scientific committees have identified the lunar south pole as the region of greatest interest for building a lasting and sustainable human settlement. However, the knowledge we have of this area is still limited. This work aims to provide a general overview of the main physical and morphological features of the lunar south pole and to propose a first iteration of spectroscopic observations within the visible range from the Asiago Astrophysical Observatory, giving a new and different perspective. The objective is to verify the feasibility of an Earth-based spectroscopic survey to detect water and the abundances of other volatiles and elements. Full article
(This article belongs to the Section Astronautics & Space Science)
►▼ Show Figures

Figure 1

Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying articles 1-22
Previous Issue
Back to TopTop