Aerospace最新文献_第3页

An Experimental Investigation of Low-Frequency Active Excitation in Scramjet Combustor Using a Micro-Pulse Detonation Engine 使用微脉冲爆破发动机对 Scramjet Combustor 中的低频主动激励进行实验研究

Aerospace Pub Date : 2024-07-08 DOI: 10.3390/aerospace11070559

Keon-Hyeong Lee, Min-Su Kim, Jeong-Yeol Choi, Kenneth H. Yu

{"title":"An Experimental Investigation of Low-Frequency Active Excitation in Scramjet Combustor Using a Micro-Pulse Detonation Engine","authors":"Keon-Hyeong Lee, Min-Su Kim, Jeong-Yeol Choi, Kenneth H. Yu","doi":"10.3390/aerospace11070559","DOIUrl":"https://doi.org/10.3390/aerospace11070559","url":null,"abstract":"A micro-pulse detonation engine (μPDE) was designed and installed to a direct-connect scramjet combustor of Pusan National University (PNU-DCSC). The active excitation on the scramjet combustor was experimentally studied using the μPDE operating at frequencies of 10–20 Hz. A vitiation air heater (VAH) was used to supply high-enthalpy vitiated air to the isolator and the scramjet combustor at a Mach number of 2.0, with a total temperature of 1600 K and a total pressure of 1.68 MPa. The exit of μPDE was located at the center of the cavity of the scramjet combustor. Active excitation was performed at equivalence ratios of 0.111 and 0.163, and characteristics were analyzed through Schlieren recording and bottom wall pressure measurement. As a result, when the detonation emitted from the μPDE entered the scramjet combustor, it instantly formed a shock train and moved forward within the scramjet combustor. The flame instantaneously changed from the cavity shear layer flame to the cavity flame. Through bottom wall pressure measurement, it was also observed that active excitation resulted in a significant pressure increase near the cavity compared to when active excitation was not performed. This revealed combustion characteristics, indicating improved combustion efficiency from the pressure increase in the scramjet combustor.","PeriodicalId":505273,"journal":{"name":"Aerospace","volume":" 756","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141669367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Deep Reinforcement Learning-Based Differential Game Guidance Law against Maneuvering Evaders 基于深度强化学习的差分博弈制导法对抗机动规避者

Aerospace Pub Date : 2024-07-06 DOI: 10.3390/aerospace11070558

Axing Xi, Yuanli Cai

{"title":"Deep Reinforcement Learning-Based Differential Game Guidance Law against Maneuvering Evaders","authors":"Axing Xi, Yuanli Cai","doi":"10.3390/aerospace11070558","DOIUrl":"https://doi.org/10.3390/aerospace11070558","url":null,"abstract":"To achieve the intelligent interception of different types of maneuvering evaders, based on deep reinforcement learning, a novel intelligent differential game guidance law is proposed in the continuous action domain. Different from traditional guidance laws, the proposed guidance law can avoid tedious manual settings and save cost efforts. First, the interception problem is transformed into the pursuit–evasion game problem, which is solved by zero-sum differential game theory. Next, the Nash equilibrium strategy is obtained through the Markov game process. To implement the proposed intelligent differential game guidance law, an actor–critic neural network based on deep deterministic policy gradient is constructed to calculate the saddle point of the differential game guidance problem. Then, a reward function is designed, which includes the tradeoffs among guidance accuracy, energy consumption, and interception time. Finally, compared with traditional methods, the interception accuracy of the proposed intelligent differential game guidance law is 99.2%, energy consumption is reduced by 47%, and simulation time is shortened by 1.58 s. All results reveal that the proposed intelligent differential game guidance law has better intelligent decision-making ability.","PeriodicalId":505273,"journal":{"name":"Aerospace","volume":" 36","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141672831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Fly-around-the-World Near-Space Picosatellite for Cost-Effective School Space Projects 用于低成本高效益学校空间项目的环绕地球飞行近地皮卡卫星

Aerospace Pub Date : 2024-07-06 DOI: 10.3390/aerospace11070557

Pirada Techavijit, Polkit Sukchalerm, Natthapong Wongphuangfuthaworn, Sureepon Kiyapaet

引用次数: 0

Compound Attitude Control Strategy for Reusable Launch Vehicle Based on Improved Particle Swarm Optimization Algorithm 基于改进型粒子群优化算法的可重复使用运载火箭复合姿态控制策略

Aerospace Pub Date : 2024-07-05 DOI: 10.3390/aerospace11070555

Shunfu Yang, Lu Gan, Tianyi Wang, Enze Zhu, Ling Yang, Hu Chen

{"title":"Compound Attitude Control Strategy for Reusable Launch Vehicle Based on Improved Particle Swarm Optimization Algorithm","authors":"Shunfu Yang, Lu Gan, Tianyi Wang, Enze Zhu, Ling Yang, Hu Chen","doi":"10.3390/aerospace11070555","DOIUrl":"https://doi.org/10.3390/aerospace11070555","url":null,"abstract":"This study introduces an advanced dual-mode compound attitude control framework for reusable launch vehicles (RLVs), underpinned by an enhanced particle swarm optimization (PSO) algorithm. This innovative strategy is tailored to meet the stringent demands for precision and robust anti-interference capabilities across the entire flight envelope of RLVs. The research commences with the formulation of a comprehensive attitude dynamics model and diverse heterogeneous actuator representations, meticulously crafted to reflect the distinct phases of RLV flight. Building upon this foundation, a synergistic control paradigm is engineered, integrating PID and fuzzy PID controllers and dynamically adjusting the inertia weights and learning factors of the PSO algorithm to achieve the balance between global and local optimization performance, complemented by a refined fitness evaluation function. The crux of the study is the application of an upgraded PSO algorithm to fine-tune the controllers’ weighting coefficients, culminating in an optimized dual-mode compound attitude control system. A series of comparative simulation analyses are thoroughly executed to appraise the system’s responsiveness, stability, precision, and resilience to interference. The simulation outcomes demonstrate an average reduction of 42.21% in step response overshoot, an 18.52% decrease in settling time, a 53.18% decline in steady-state error, a 56.80% drop in the maximum deviation value, a 55.82% improvement in recovery speed, and a 75.61% enhancement in tracking precision for the proposed controller. The findings clearly verify the superior performance of the proposed control system, affirming its contribution to the advancement of RLV attitude control. The proposed controller holds promising potential for real application in attitude control systems and is poised to augment the reliability and mission success rate of RLVs under intricate flight scenarios.","PeriodicalId":505273,"journal":{"name":"Aerospace","volume":" 35","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141675948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Numerical Investigation of Flame-Acoustic Interaction at Resonant and Non-Resonant Conditions in a Model Combustion Chamber 模拟燃烧室中共振和非共振条件下火焰与声波相互作用的数值研究

Aerospace Pub Date : 2024-07-05 DOI: 10.3390/aerospace11070556

T. Horchler, S. Fechter, J. Hardi

{"title":"Numerical Investigation of Flame-Acoustic Interaction at Resonant and Non-Resonant Conditions in a Model Combustion Chamber","authors":"T. Horchler, S. Fechter, J. Hardi","doi":"10.3390/aerospace11070556","DOIUrl":"https://doi.org/10.3390/aerospace11070556","url":null,"abstract":"Despite considerable research effort in the past 60 years, the occurrence of combustion instabilities in rocket engines is still not fully understood. While the physical mechanisms involved have been studied separately and are well understood in a controlled environment, the exact interaction of fluid dynamics, thermodynamics, chemical reactions, heat-release and acoustics, ultimately leading to instabilities, is not yet known. This paper focuses on the investigation of flame-acoustic interaction in a model combustion chamber using detached-eddy simulation (DES) methods. We present simulation results for a new load point of combustion chamber H from DLR Lampoldshausen and explore the flame response to resonant and non-resonant external excitation. In the first part of the paper, we use time-averaged results from a steady-state flow field without siren excitation to calculate the combustion chamber Helmholtz eigenmodes and compare them to the experimental results. The second part of the paper presents simulation results at a non-resonant excitation frequency. These results agree very well with the experimental results at the same condition, although the numerical simulation systematically overestimates the oscillation amplitudes. In the third part, we show that a simulation with resonant siren excitation can correctly reproduce the shift in eigenmode frequencies that is also seen in the experiments. Additionally, for this new load point, we confirm previous numerical results showing a strong influence of transversal excitation on the shape of the dense LOx cores. This work also proposes a bombing method for determining the resonant eigenmode frequencies based on an unexcited steady-state DES by simulating the decay of a strong artificial pressure pulse inside the combustion chamber.","PeriodicalId":505273,"journal":{"name":"Aerospace","volume":" 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141674352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Study on Heat Transfer Characteristics of Jet Impingement of Turbine Bending Surface 涡轮机弯曲表面喷流冲击传热特性研究

Aerospace Pub Date : 2024-07-05 DOI: 10.3390/aerospace11070554

Fei Zeng, Ruijia Sun, Zhenhua Chen, Yuang Liu, Weihua Yang

引用次数: 0

Inter-Satellite Link Prediction with Supervised Learning: An Application in Polar Orbits 利用监督学习进行卫星间链路预测：极轨应用

Aerospace Pub Date : 2024-07-04 DOI: 10.3390/aerospace11070551

Estel Ferrer, J. A. Ruiz-de-Azua, Francesc Betorz, Josep Escrig

{"title":"Inter-Satellite Link Prediction with Supervised Learning: An Application in Polar Orbits","authors":"Estel Ferrer, J. A. Ruiz-de-Azua, Francesc Betorz, Josep Escrig","doi":"10.3390/aerospace11070551","DOIUrl":"https://doi.org/10.3390/aerospace11070551","url":null,"abstract":"Distributed space systems are increasingly valued in the space industry, as they enhance mission performance through collaborative efforts and resource sharing among multiple heterogeneous satellites. Additionally, enabling autonomous and real-time satellite-to-satellite communications through Inter-Satellite Links (ISLs) can further increase the overall performance by allowing cooperation without relying on ground links and extensive coordination efforts among diverse stakeholders. Given the constrained resources available onboard satellites, a crucial element of achieving cost-effective and autonomous cooperation involves minimizing energy wastage resulting from unsuccessful or unnecessary communication. To address this challenge, satellites must anticipate their ISL opportunities or encounters with minimal resource utilization. Building upon prior publications, this work presents further insights into the use of supervised learning to enable satellites to forecast their encounters without relying on orbit propagation. In particular, a more realistic definition of satellite encounters, along with a versatile solution applicable to all polar low-Earth orbit satellites is implemented. Results show that the trained model can anticipate encounters for realistic and unseen data from an available data source with a balance accuracy of around 90% and six times faster when compared with the well-known Simplified General Perturbation 4 orbital model.","PeriodicalId":505273,"journal":{"name":"Aerospace","volume":" 18","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141678374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Three-Dimensional Characterization of Residual Stress in Aircraft Riveted Panel Structures 飞机铆接板结构残余应力的三维表征

Aerospace Pub Date : 2024-07-04 DOI: 10.3390/aerospace11070552

Yonggang Kang, Huantian Xiao, Zihao Wang, Guomao Li, Yonggang Chen

引用次数: 0

Design of Reverse Bleed Slot for Curved Axisymmetric Inlet Based on Kantrowitz Criterion and Flow Field Characteristics 基于 Kantrowitz 准则和流场特征的曲线轴对称进水口反向排放槽设计

Aerospace Pub Date : 2024-07-04 DOI: 10.3390/aerospace11070553

Yongzhou Li, Di Sun, Xinhui Tian, Yiqi Yuan, Xisheng Luo, Kunyuan Zhang

{"title":"Design of Reverse Bleed Slot for Curved Axisymmetric Inlet Based on Kantrowitz Criterion and Flow Field Characteristics","authors":"Yongzhou Li, Di Sun, Xinhui Tian, Yiqi Yuan, Xisheng Luo, Kunyuan Zhang","doi":"10.3390/aerospace11070553","DOIUrl":"https://doi.org/10.3390/aerospace11070553","url":null,"abstract":"Conventional forward bleed slots reduce the hypersonic inlet starting Mach number but suffer from excessive flow leakage after restart. This paper proposes a novel reverse bleed slot design method for curved axisymmetric inlets of a solid-fuel scramjet. Leveraging the Kantrowitz criterion and detailed flow analysis, the method optimizes bleed slot placement, number, area, and angle. Results show superior aerodynamic performance by placing slots in the non-starting region of the internal compression section, considering both unstarted flow and separation bubble dynamics during restart. Each bleed slot area is calculated successively down-stream based on the Kantrowitz criterion. Finally, the effects of bleed slot angle have been extensively studied. The key inlet performance reaches its optimum at a slot angle of approximately 130°, achieving a significant reduction in the starting Mach number (from 4.80 to 3.65) and a 50% decrease in bleed flow rate compared to the forward slot design. This method demonstrates its feasibility and effectiveness, enabling substantial improvement in inlet starting performance with minimal flow loss.","PeriodicalId":505273,"journal":{"name":"Aerospace","volume":" 57","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141680118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Numerical Simulation of Gas Flow Coupled with Burning Surface Regression Based on Immersed Boundary Method and Face Offsetting Method 基于沉浸边界法和面偏移法的气体流动与燃烧面回归数值模拟

Aerospace Pub Date : 2024-07-04 DOI: 10.3390/aerospace11070550

Dongjian Su, Qingyu Lin, Hao Wang, Ruyi Tao

{"title":"Numerical Simulation of Gas Flow Coupled with Burning Surface Regression Based on Immersed Boundary Method and Face Offsetting Method","authors":"Dongjian Su, Qingyu Lin, Hao Wang, Ruyi Tao","doi":"10.3390/aerospace11070550","DOIUrl":"https://doi.org/10.3390/aerospace11070550","url":null,"abstract":"The coupling action of gas flow with propellant burning surface regression is the critical process in solid rocket motor (SRM), which has an important effect on the unsteady combustion, erosive burning, dynamic combustion and pressure fluctuation of propellants. The immersed boundary method (IBM) is used to deal with the dynamic boundary of the flow field caused by the burning surface regression, and the face offsetting method (FOM) is applied to track the regression of the burning surface. The combination of these two methods can realize the coupling simulation of gas flow and burning surface regression. In this paper, the mathematical model of the immersed boundary method for all the flow field boundaries and the coupling method of gas flow with the propellant burning surface regression are given. And the implementation method of the immersed boundary method for all boundary conditions in the non-viscous flow field is given. The internal flow fields of the motor with the end-slotted and end-burning propellant and another motor with the perforated cylindrical propellant, considering the erosive burning, are simulated. The numerical results show that IBM, combined with FOM, has effectively realized the simulation of gas flow coupled with the burning surface regression.","PeriodicalId":505273,"journal":{"name":"Aerospace","volume":" 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141677092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0