In this paper, a pawl composite linkage transfer mechanism is designed for the automatic in-orbit sample transfer mission of Chang’E-5 lunar sample return mission, which can realize the sample container in-orbit transfer under various critical constraints such as lightweight, miniaturization, and narrow working space. Resistance during the whole process as well as the sensitive factors that affect the resistance during the sample container transfer process are investigated and designed. The sample container transfer process has been verified by the test system on the ground, indicating that the design can satisfy the requirements of the sample transfer mission. The developed transfer mechanism completed the Chang’E-5 sample return mission successfully with good consistency between space and ground, verifying the correctness and effectiveness of the design.
{"title":"Design of In-Orbit Sample Container Transfer Mechanism for Chang’E-5 Lunar Sample Return Mission","authors":"Weijun Wang, Yuxin Cui, Chenkun Qi, Yanyan Cao, Yuhua Zhang, Chongfeng Zhang, Shigang Wang","doi":"10.3390/aerospace10120992","DOIUrl":"https://doi.org/10.3390/aerospace10120992","url":null,"abstract":"In this paper, a pawl composite linkage transfer mechanism is designed for the automatic in-orbit sample transfer mission of Chang’E-5 lunar sample return mission, which can realize the sample container in-orbit transfer under various critical constraints such as lightweight, miniaturization, and narrow working space. Resistance during the whole process as well as the sensitive factors that affect the resistance during the sample container transfer process are investigated and designed. The sample container transfer process has been verified by the test system on the ground, indicating that the design can satisfy the requirements of the sample transfer mission. The developed transfer mechanism completed the Chang’E-5 sample return mission successfully with good consistency between space and ground, verifying the correctness and effectiveness of the design.","PeriodicalId":48525,"journal":{"name":"Aerospace","volume":"50 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139236718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-25DOI: 10.3390/aerospace10120990
Haohao Wang, Limin Gao, Baohai Wu
Many probability-based uncertainty quantification (UQ) schemes require a large amount of sampled data to build credible probability density function (PDF) models for uncertain parameters. Unfortunately, the amounts of data collected as to compressor blades of aero-engines are mostly limited due to the expensive and time-consuming tests. In this paper, we develop a preconditioner-based data-driven polynomial chaos (PDDPC) method that can efficiently deal with uncertainty propagation of limited amounts of sampled data. The calculation accuracy of a PDDPC method is closely related to the sample size of collected data. Therefore, the influence of sample size on this PDDPC method is investigated using a nonlinear test function. Subsequently, we consider the real manufacturing errors in stagger angles for compressor blades. Under three different operating conditions, the PDDPC method is applied to investigate the effect of stagger-angle error on UQ results of multiple aerodynamic parameters of a two-dimensional compressor blade. The results show that as the sample-size of measured data increases, UQ results regarding aerodynamic performance obtained by the PDDPC method gradually converge. There exists a critical sample size that ensures accurate UQ analysis of compressor blades. The probability information contained in the machining error data is analyzed through Kullback–Leibler divergence, and the critical sample size is determined. The research results can serve as a valuable reference for the fast and cheap UQ analysis of compressor blades in practical engineering.
{"title":"Critical Sample-Size Analysis for Uncertainty Aerodynamic Evaluation of Compressor Blades with Stagger-Angle Errors","authors":"Haohao Wang, Limin Gao, Baohai Wu","doi":"10.3390/aerospace10120990","DOIUrl":"https://doi.org/10.3390/aerospace10120990","url":null,"abstract":"Many probability-based uncertainty quantification (UQ) schemes require a large amount of sampled data to build credible probability density function (PDF) models for uncertain parameters. Unfortunately, the amounts of data collected as to compressor blades of aero-engines are mostly limited due to the expensive and time-consuming tests. In this paper, we develop a preconditioner-based data-driven polynomial chaos (PDDPC) method that can efficiently deal with uncertainty propagation of limited amounts of sampled data. The calculation accuracy of a PDDPC method is closely related to the sample size of collected data. Therefore, the influence of sample size on this PDDPC method is investigated using a nonlinear test function. Subsequently, we consider the real manufacturing errors in stagger angles for compressor blades. Under three different operating conditions, the PDDPC method is applied to investigate the effect of stagger-angle error on UQ results of multiple aerodynamic parameters of a two-dimensional compressor blade. The results show that as the sample-size of measured data increases, UQ results regarding aerodynamic performance obtained by the PDDPC method gradually converge. There exists a critical sample size that ensures accurate UQ analysis of compressor blades. The probability information contained in the machining error data is analyzed through Kullback–Leibler divergence, and the critical sample size is determined. The research results can serve as a valuable reference for the fast and cheap UQ analysis of compressor blades in practical engineering.","PeriodicalId":48525,"journal":{"name":"Aerospace","volume":"15 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139236810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-25DOI: 10.3390/aerospace10120991
Tao Zhang, Xinyu Song, X. Kai, Yeguang He, Rundong Li
In order to understand the breakup characteristics of a transverse liquid jet flow in an actual combustion chamber, a numerical study was conducted using the Volume of Fluid (VOF) method combined with grid adaptation technology. The study focused on the primary breakup characteristics of liquid jets under the conditions of a steady and oscillating air crossflow. The simulated mediums were set to water and air. The research findings revealed that fluctuations in the incoming gas velocity can influence the development speed of surface waves and the mode of jet breakup during the initial stage of jet development as compared to the steady condition. In both conditions, the surface waves were initially observed to appear within 1/4 T–2/4 T. The surface wave of the jet develops faster under steady conditions because the average velocity of the steady flow is higher than that of the oscillation flow during this stage. As a result, the fragmentation of the jet is primarily influenced by the surface wave. Under an oscillating flow, the rear of the jet begins to break up earlier due to the slower development of surface waves. The velocity of the oscillating air inflow increases over time, and the speed of surface wave development also increases, gradually leading to the dominance of surface-wave-induced jet breakup. In the second stage of air inflow oscillation, an “up and down slapping” phenomenon occurs at the tail of the jet. Additionally, increasing the air inflow velocity leads to a longer jet breakup length and a higher number of droplets near the jet column. Surface waves are observed on both the windward and leeward sides of the jet. The penetration depth of the jet fluctuates with changes in the crossflow velocity, and the response of the jet penetration depth to the velocity fluctuations in the transverse air is delayed by half a period.
为了了解实际燃烧室中横向液体射流的破裂特性，我们采用流体体积法（VOF）结合网格适应技术进行了数值研究。研究的重点是稳定和振荡空气横流条件下液体射流的初级破裂特性。模拟介质设置为水和空气。研究结果表明，与稳定条件相比，进入的气体速度波动会影响表面波的发展速度以及射流发展初期的射流破裂模式。在这两种条件下，最初观察到的表面波都出现在 1/4 T-2/4 T 内。在稳定条件下，射流的表面波发展速度更快，因为在这一阶段，稳定流的平均速度高于振荡流。因此，射流的破碎主要受表面波的影响。在振荡气流下，由于表面波的发展速度较慢，射流后部开始碎裂的时间较早。随着时间的推移，振荡空气流入的速度会增加，表面波的发展速度也会增加，逐渐导致表面波引起的射流破裂占主导地位。在空气流入振荡的第二阶段，射流尾部会出现 "上下拍击 "现象。此外，增加空气流入速度会导致更长的射流破裂长度和更多的液滴靠近射流柱。在射流的迎风面和背风面都能观察到表面波。射流的穿透深度随横向气流速度的变化而波动，射流穿透深度对横向气流速度波动的响应延迟半个周期。
{"title":"Numerical Simulation on Primary Breakup Characteristics of Liquid Jet in Oscillation Crossflow","authors":"Tao Zhang, Xinyu Song, X. Kai, Yeguang He, Rundong Li","doi":"10.3390/aerospace10120991","DOIUrl":"https://doi.org/10.3390/aerospace10120991","url":null,"abstract":"In order to understand the breakup characteristics of a transverse liquid jet flow in an actual combustion chamber, a numerical study was conducted using the Volume of Fluid (VOF) method combined with grid adaptation technology. The study focused on the primary breakup characteristics of liquid jets under the conditions of a steady and oscillating air crossflow. The simulated mediums were set to water and air. The research findings revealed that fluctuations in the incoming gas velocity can influence the development speed of surface waves and the mode of jet breakup during the initial stage of jet development as compared to the steady condition. In both conditions, the surface waves were initially observed to appear within 1/4 T–2/4 T. The surface wave of the jet develops faster under steady conditions because the average velocity of the steady flow is higher than that of the oscillation flow during this stage. As a result, the fragmentation of the jet is primarily influenced by the surface wave. Under an oscillating flow, the rear of the jet begins to break up earlier due to the slower development of surface waves. The velocity of the oscillating air inflow increases over time, and the speed of surface wave development also increases, gradually leading to the dominance of surface-wave-induced jet breakup. In the second stage of air inflow oscillation, an “up and down slapping” phenomenon occurs at the tail of the jet. Additionally, increasing the air inflow velocity leads to a longer jet breakup length and a higher number of droplets near the jet column. Surface waves are observed on both the windward and leeward sides of the jet. The penetration depth of the jet fluctuates with changes in the crossflow velocity, and the response of the jet penetration depth to the velocity fluctuations in the transverse air is delayed by half a period.","PeriodicalId":48525,"journal":{"name":"Aerospace","volume":"33 8","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139237969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-24DOI: 10.3390/aerospace10120989
Lei Liu, Guozhan Li, Ban Wang, Shaofeng Wu
This study presents a numerical investigation of suction control in an aggressive S-shaped air intake with large boundary ingestion. The results show that the variation of suction control parameters such as suction location, suction pipe diameter, and suction angle all have an impact on the effectiveness of the flow control. In general, further upstream suction, such as near the throat, is favorable for the decrease of the second flow intensity and the area of the low-energy fluid region at the exit of the S-shaped inlet. However, it is bad for the total pressure recovery and the circumferential total pressure uniform distribution. From the perspective of the uniformity of the total pressure distribution at the air intake exit, there is an optimal location for suction between the throat and the separation start point. A bigger suction pipe diameter brings better effects as the suction location and suction angle keep constant, due to more low-energy fluid being sucked out. But this doesn’t mean the largest mass flow suction results in the biggest improvement. Overall, sucking at the 1st bend, with suction angle and suction pipe diameter equaling 15 degrees and 12 mm, respectively, is the optimal suction scheme here. Since the change rule of the cross-section area along the centerline has not changed during suction control, the second flow and complex surface streamline at the air intake exit cannot be eliminated, though they can be decreased a lot with reasonable suction control. Similarly, owing to large boundary ingestion, the remarkable low-energy fluid region always exists despite the significant reduction of the separation and second flow, which is very different from the results of this kind of micro-suction executed in the non-BLI S-duct. To pursue a higher improvement, suction combined with vortex generator vanes has been further studied. Corresponding results analysis shows that the hybrid flow control method has great potential and should be investigated in detail in the future.
本研究对具有大边界摄入的侵蚀性 S 形进气口的吸力控制进行了数值研究。结果表明，吸气位置、吸气管直径和吸气角度等吸气控制参数的变化都会影响流量控制的效果。一般来说，进一步向上游吸气（如靠近喉管处）有利于降低 S 形入口出口处的二次流强度和低能流体区域的面积。但对总压恢复和圆周总压均匀分布不利。从进气口出口处总压分布均匀性的角度来看，喉管和分离起始点之间有一个最佳的吸气位置。由于吸入的低能流体较多，吸入位置和吸入角度保持不变，因此吸入管直径越大，效果越好。但这并不意味着质量流量越大的吸气效果就越好。总体而言，在第 1 个弯道处吸入，吸入角和吸入管直径分别等于 15 度和 12 毫米，是此处的最佳吸入方案。由于在吸气控制过程中，沿中心线截面积的变化规律没有改变，因此进气口的二次流和复杂的表面流线无法消除，但通过合理的吸气控制可以大大减少。同样，由于边界摄入量大，尽管分离流和二次流显著减少，但显著的低能流体区域始终存在，这与在非BLI S 型管道中执行这种微抽吸的结果大相径庭。为了追求更大的改进，我们进一步研究了与涡流发生器叶片相结合的吸力。相应的结果分析表明，混合流量控制方法具有很大的潜力，应在未来进行详细研究。
{"title":"Suction Control of a Boundary Layer Ingestion Inlet","authors":"Lei Liu, Guozhan Li, Ban Wang, Shaofeng Wu","doi":"10.3390/aerospace10120989","DOIUrl":"https://doi.org/10.3390/aerospace10120989","url":null,"abstract":"This study presents a numerical investigation of suction control in an aggressive S-shaped air intake with large boundary ingestion. The results show that the variation of suction control parameters such as suction location, suction pipe diameter, and suction angle all have an impact on the effectiveness of the flow control. In general, further upstream suction, such as near the throat, is favorable for the decrease of the second flow intensity and the area of the low-energy fluid region at the exit of the S-shaped inlet. However, it is bad for the total pressure recovery and the circumferential total pressure uniform distribution. From the perspective of the uniformity of the total pressure distribution at the air intake exit, there is an optimal location for suction between the throat and the separation start point. A bigger suction pipe diameter brings better effects as the suction location and suction angle keep constant, due to more low-energy fluid being sucked out. But this doesn’t mean the largest mass flow suction results in the biggest improvement. Overall, sucking at the 1st bend, with suction angle and suction pipe diameter equaling 15 degrees and 12 mm, respectively, is the optimal suction scheme here. Since the change rule of the cross-section area along the centerline has not changed during suction control, the second flow and complex surface streamline at the air intake exit cannot be eliminated, though they can be decreased a lot with reasonable suction control. Similarly, owing to large boundary ingestion, the remarkable low-energy fluid region always exists despite the significant reduction of the separation and second flow, which is very different from the results of this kind of micro-suction executed in the non-BLI S-duct. To pursue a higher improvement, suction combined with vortex generator vanes has been further studied. Corresponding results analysis shows that the hybrid flow control method has great potential and should be investigated in detail in the future.","PeriodicalId":48525,"journal":{"name":"Aerospace","volume":"31 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139240881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-23DOI: 10.3390/aerospace10120986
Ruifan Hu, Yongliang Chen, Jifei Wu, Shuling Tian
At cryogenic temperatures, gases exhibit significant deviations from ideal behaviour, and the commonly employed gas model may inadequately represent the thermodynamic properties of cryogenic gases, subsequently impacting numerical simulations using various thermodynamic and transport models at cryogenic temperatures. The findings of this study reveal that the relative errors in aerodynamic characteristics obtained through different isentropic relations are noteworthy, with the maximum relative error in the drag coefficient reaching 16%. The impact of the equation of state, viscosity model, and thermal conductivity model is relatively minor, with relative errors in the pressure drag coefficient and viscous drag coefficient remaining well below 1%. Nevertheless, the relative error in the skin friction coefficient cannot be ignored due to transonic shock wave/boundary layer interactions. Consequently, when conducting numerical simulations of cryogenic flow, it is imperative to select appropriate gas models to attain precise results.
{"title":"The Influence of Gas Models on Numerical Simulations of Cryogenic Flow","authors":"Ruifan Hu, Yongliang Chen, Jifei Wu, Shuling Tian","doi":"10.3390/aerospace10120986","DOIUrl":"https://doi.org/10.3390/aerospace10120986","url":null,"abstract":"At cryogenic temperatures, gases exhibit significant deviations from ideal behaviour, and the commonly employed gas model may inadequately represent the thermodynamic properties of cryogenic gases, subsequently impacting numerical simulations using various thermodynamic and transport models at cryogenic temperatures. The findings of this study reveal that the relative errors in aerodynamic characteristics obtained through different isentropic relations are noteworthy, with the maximum relative error in the drag coefficient reaching 16%. The impact of the equation of state, viscosity model, and thermal conductivity model is relatively minor, with relative errors in the pressure drag coefficient and viscous drag coefficient remaining well below 1%. Nevertheless, the relative error in the skin friction coefficient cannot be ignored due to transonic shock wave/boundary layer interactions. Consequently, when conducting numerical simulations of cryogenic flow, it is imperative to select appropriate gas models to attain precise results.","PeriodicalId":48525,"journal":{"name":"Aerospace","volume":"8 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139244765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-23DOI: 10.3390/aerospace10120985
D. Ryan, Sophie Musset, H. Reid, Säm Krucker, A. Battaglia, Eric Bréelle, Claude Chapron, H. Collier, J. Dahlin, C. Denker, E. Dickson, Peter T. Gallagher, I. Hannah, N. Jeffrey, J. Kašparová, E. Kontar, P. Laurent, S. Maloney, P. Massa, A. Massone, Tomasz Mrozek, D. Pailot, M. Pallu, M. Pesce-Rollins, Michele Piana, Illya Plotnikov, A. Rouillard, Albert Y. Shih, David Smith, M. Stȩślicki, Muriel Z. Stiefel, A. Warmuth, Meetu Verma, Astrid M. Veronig, N. Vilmer, C. Vocks, A. Volpara
Models of particle acceleration in solar eruptive events suggest that roughly equal energy may go into accelerating electrons and ions. However, while previous solar X-ray spectroscopic imagers have transformed our understanding of electron acceleration, only one resolved image of γ-ray emission from solar accelerated ions has ever been produced. This paper outlines a new satellite instrument concept—the large imaging spectrometer for solar accelerated nuclei (LISSAN)—with the capability not only to observe hundreds of events over its lifetime, but also to capture multiple images per event, thereby imaging the dynamics of solar accelerated ions for the first time. LISSAN provides spectroscopic imaging at photon energies of 40 keV–100 MeV on timescales of ≲10 s with greater sensitivity and imaging capability than its predecessors. This is achieved by deploying high-resolution scintillator detectors and indirect Fourier imaging techniques. LISSAN is suitable for inclusion in a multi-instrument platform such as an ESA M-class mission or as a smaller standalone mission. Without the observations that LISSAN can provide, our understanding of solar particle acceleration, and hence the space weather events with which it is often associated, cannot be complete.
太阳爆发事件中的粒子加速模型表明，加速电子和离子的能量可能大致相同。然而，虽然以前的太阳 X 射线光谱成像仪改变了我们对电子加速的理解，但只有一张太阳加速离子发射的 γ 射线分辨图像。本文概述了一种新的卫星仪器概念--太阳加速核大型成像光谱仪（LISSAN）--不仅能够在其生命周期内观测数百个事件，而且能够捕捉每个事件的多幅图像，从而首次对太阳加速离子的动态进行成像。LISSAN 可在 ≲10 秒的时间尺度上对 40 keV-100 MeV 的光子能量进行光谱成像，其灵敏度和成像能力均高于其前身。这是通过部署高分辨率闪烁探测器和间接傅立叶成像技术实现的。LISSAN 适合纳入欧空局 M 级飞行任务等多仪器平台，或作为较小的独立飞行任务。如果没有 LISSAN 能够提供的观测，我们对太阳粒子加速的了解就不可能完整，因此也就不可能了解经常与之相关的空间气象事件。
{"title":"The Large Imaging Spectrometer for Solar Accelerated Nuclei (LISSAN): A Next-Generation Solar γ-ray Spectroscopic Imaging Instrument Concept","authors":"D. Ryan, Sophie Musset, H. Reid, Säm Krucker, A. Battaglia, Eric Bréelle, Claude Chapron, H. Collier, J. Dahlin, C. Denker, E. Dickson, Peter T. Gallagher, I. Hannah, N. Jeffrey, J. Kašparová, E. Kontar, P. Laurent, S. Maloney, P. Massa, A. Massone, Tomasz Mrozek, D. Pailot, M. Pallu, M. Pesce-Rollins, Michele Piana, Illya Plotnikov, A. Rouillard, Albert Y. Shih, David Smith, M. Stȩślicki, Muriel Z. Stiefel, A. Warmuth, Meetu Verma, Astrid M. Veronig, N. Vilmer, C. Vocks, A. Volpara","doi":"10.3390/aerospace10120985","DOIUrl":"https://doi.org/10.3390/aerospace10120985","url":null,"abstract":"Models of particle acceleration in solar eruptive events suggest that roughly equal energy may go into accelerating electrons and ions. However, while previous solar X-ray spectroscopic imagers have transformed our understanding of electron acceleration, only one resolved image of γ-ray emission from solar accelerated ions has ever been produced. This paper outlines a new satellite instrument concept—the large imaging spectrometer for solar accelerated nuclei (LISSAN)—with the capability not only to observe hundreds of events over its lifetime, but also to capture multiple images per event, thereby imaging the dynamics of solar accelerated ions for the first time. LISSAN provides spectroscopic imaging at photon energies of 40 keV–100 MeV on timescales of ≲10 s with greater sensitivity and imaging capability than its predecessors. This is achieved by deploying high-resolution scintillator detectors and indirect Fourier imaging techniques. LISSAN is suitable for inclusion in a multi-instrument platform such as an ESA M-class mission or as a smaller standalone mission. Without the observations that LISSAN can provide, our understanding of solar particle acceleration, and hence the space weather events with which it is often associated, cannot be complete.","PeriodicalId":48525,"journal":{"name":"Aerospace","volume":"47 6","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139246248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-23DOI: 10.3390/aerospace10120988
I. O. Shamshin, Vladislav S. Ivanov, V. S. Aksenov, Pavel A. Gusev, K. A. Avdeev, Sergey M. Frolov
Rotating detonation engines (RDEs) are considered to be promising thrusters for aerospace propulsion. Detonation initiation in RDEs can be accompanied by a destructive explosion of an excess volume of the fuel mixture in the combustor. To exclude this phenomenon, a “mild” rather than “strong” initiation of detonation is required. For the mild initiation of detonation in RDEs, it is necessary to ignite a mixture of a certain minimum volume sufficient for deflagration-to-detonation transition (DDT). In this study, the critical conditions for detonation initiation through DDT in a semiconfined slit combustor simulating the RDE combustor with a separate supply of ethylene and oxygen diluted with nitrogen (from 0 to 40%) were obtained experimentally. It turned out that for the mild initiation of detonation, it is necessary to ignite the mixture upon reaching the critical (minimum) height of the combustible mixture layer. Thus, for the mild initiation of detonation in the undiluted C2H4 + 3O2 mixture filling such a slit combustor, the height of the mixture layer must exceed the slit width by approximately a factor of 12. In terms of the transverse size of the detonation cell λ the minimum layer height of such mixtures in experiments is ~150λ. Compared to the experiments with the premixed composition, the critical height of the layer is 20% larger, which is explained by the finite rate of mixing. As the degree of oxygen dilution with nitrogen increases, the critical height of the layer increases, and the role of finite rate mixing decreases: the results no longer depend on the method of combustible mixture formation.
{"title":"Mild Detonation Initiation in Rotating Detonation Engines: An Experimental Study of the Deflagration-to-Detonation Transition in a Semiconfined Flat Slit Combustor with Separate Supplies of Fuel and Oxidizer","authors":"I. O. Shamshin, Vladislav S. Ivanov, V. S. Aksenov, Pavel A. Gusev, K. A. Avdeev, Sergey M. Frolov","doi":"10.3390/aerospace10120988","DOIUrl":"https://doi.org/10.3390/aerospace10120988","url":null,"abstract":"Rotating detonation engines (RDEs) are considered to be promising thrusters for aerospace propulsion. Detonation initiation in RDEs can be accompanied by a destructive explosion of an excess volume of the fuel mixture in the combustor. To exclude this phenomenon, a “mild” rather than “strong” initiation of detonation is required. For the mild initiation of detonation in RDEs, it is necessary to ignite a mixture of a certain minimum volume sufficient for deflagration-to-detonation transition (DDT). In this study, the critical conditions for detonation initiation through DDT in a semiconfined slit combustor simulating the RDE combustor with a separate supply of ethylene and oxygen diluted with nitrogen (from 0 to 40%) were obtained experimentally. It turned out that for the mild initiation of detonation, it is necessary to ignite the mixture upon reaching the critical (minimum) height of the combustible mixture layer. Thus, for the mild initiation of detonation in the undiluted C2H4 + 3O2 mixture filling such a slit combustor, the height of the mixture layer must exceed the slit width by approximately a factor of 12. In terms of the transverse size of the detonation cell λ the minimum layer height of such mixtures in experiments is ~150λ. Compared to the experiments with the premixed composition, the critical height of the layer is 20% larger, which is explained by the finite rate of mixing. As the degree of oxygen dilution with nitrogen increases, the critical height of the layer increases, and the role of finite rate mixing decreases: the results no longer depend on the method of combustible mixture formation.","PeriodicalId":48525,"journal":{"name":"Aerospace","volume":"128 ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139245611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-22DOI: 10.3390/aerospace10120978
Nanxing Shi, Yunsong Gu, Tingting Wu, Yuhang Zhou, Yi Wang, Shuai Deng
This research developed a pressure-based thrust vectoring angle estimation method for fluidic thrust vectoring nozzles. This method can accurately estimate the real-time in-flight thrust vectoring angle using only wall pressure information on the inner surface of the nozzle. We proposed an algorithm to calculate the thrust vectoring angle from the wall pressure inside the nozzle. Non-dominated sorting genetic algorithm II was applied to find the optimal sensor arrays and reduce the wall pressure sensor quantity. Synchronous force and wall pressure measurement experiments were carried out to verify the accuracy and real-time response of the pressure-based thrust vectoring angle estimation method. The results showed that accurate estimation of the thrust vectoring angle can be achieved with a minimum of three pressure sensors. The pressure-based thrust vectoring angle estimation method proposed in this study has a good prospect for engineering applications; it is capable of accurate real-time in-flight monitoring of the thrust vectoring angle. This method is important and indispensable for the closed-loop feedback control and aircraft attitude control of fluidic thrust vectoring control technology.
这项研究为流体推力矢量喷嘴开发了一种基于压力的推力矢量角估算方法。该方法仅利用喷嘴内表面的壁压信息就能准确估算出飞行中的实时推力矢量角。我们提出了一种根据喷嘴内壁压力计算推力矢量角的算法。应用非支配排序遗传算法 II 寻找最佳传感器阵列，减少壁压传感器数量。为验证基于压力的推力矢量角估算方法的准确性和实时响应，进行了同步力和壁压测量实验。结果表明，至少使用三个压力传感器就能实现推力矢量角的精确估算。本研究提出的基于压力的推力矢量角估算方法具有良好的工程应用前景，它能够对飞行中的推力矢量角进行准确的实时监测。该方法对于流体推力矢量控制技术的闭环反馈控制和飞机姿态控制具有不可或缺的重要意义。
{"title":"An Optimized Pressure-Based Method for Thrust Vectoring Angle Estimation","authors":"Nanxing Shi, Yunsong Gu, Tingting Wu, Yuhang Zhou, Yi Wang, Shuai Deng","doi":"10.3390/aerospace10120978","DOIUrl":"https://doi.org/10.3390/aerospace10120978","url":null,"abstract":"This research developed a pressure-based thrust vectoring angle estimation method for fluidic thrust vectoring nozzles. This method can accurately estimate the real-time in-flight thrust vectoring angle using only wall pressure information on the inner surface of the nozzle. We proposed an algorithm to calculate the thrust vectoring angle from the wall pressure inside the nozzle. Non-dominated sorting genetic algorithm II was applied to find the optimal sensor arrays and reduce the wall pressure sensor quantity. Synchronous force and wall pressure measurement experiments were carried out to verify the accuracy and real-time response of the pressure-based thrust vectoring angle estimation method. The results showed that accurate estimation of the thrust vectoring angle can be achieved with a minimum of three pressure sensors. The pressure-based thrust vectoring angle estimation method proposed in this study has a good prospect for engineering applications; it is capable of accurate real-time in-flight monitoring of the thrust vectoring angle. This method is important and indispensable for the closed-loop feedback control and aircraft attitude control of fluidic thrust vectoring control technology.","PeriodicalId":48525,"journal":{"name":"Aerospace","volume":"301 ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139249353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-22DOI: 10.3390/aerospace10120982
Zhiqian Zhang, Lei Liu, Lin Quan, Guohong Shen, Rui Zhang, Yuqi Jiang, Yuxiong Xue, Xianghua Zeng
Accurately predicting proton flux in the space radiation environment is crucial for satellite in-orbit management and space science research. This paper proposes a proton flux prediction method based on a hybrid neural network. This method is a predictive approach for measuring proton flux profiles via a satellite during its operation, including crossings through the SAA region. In the data preprocessing stage, a moving average wavelet transform was employed to retain the trend information of the original data and perform noise reduction. For the model design, the TPA-LSTM model was introduced, which combines the Temporal Pattern Attention mechanism with a Long Short-Term Memory network (LSTM). The model was trained and validated using 4,174,202 proton flux data points over a span of 12 months. The experimental results indicate that the prediction accuracy of the TPA-LSTM model is higher than that of the AP-8 model, with a logarithmic root mean square error (logRMSE) of 3.71 between predicted and actual values. In particular, an improved accuracy was observed when predicting values within the South Atlantic Anomaly (SAA) region, with a logRMSE of 3.09.
{"title":"A Proton Flux Prediction Method Based on an Attention Mechanism and Long Short-Term Memory Network","authors":"Zhiqian Zhang, Lei Liu, Lin Quan, Guohong Shen, Rui Zhang, Yuqi Jiang, Yuxiong Xue, Xianghua Zeng","doi":"10.3390/aerospace10120982","DOIUrl":"https://doi.org/10.3390/aerospace10120982","url":null,"abstract":"Accurately predicting proton flux in the space radiation environment is crucial for satellite in-orbit management and space science research. This paper proposes a proton flux prediction method based on a hybrid neural network. This method is a predictive approach for measuring proton flux profiles via a satellite during its operation, including crossings through the SAA region. In the data preprocessing stage, a moving average wavelet transform was employed to retain the trend information of the original data and perform noise reduction. For the model design, the TPA-LSTM model was introduced, which combines the Temporal Pattern Attention mechanism with a Long Short-Term Memory network (LSTM). The model was trained and validated using 4,174,202 proton flux data points over a span of 12 months. The experimental results indicate that the prediction accuracy of the TPA-LSTM model is higher than that of the AP-8 model, with a logarithmic root mean square error (logRMSE) of 3.71 between predicted and actual values. In particular, an improved accuracy was observed when predicting values within the South Atlantic Anomaly (SAA) region, with a logRMSE of 3.09.","PeriodicalId":48525,"journal":{"name":"Aerospace","volume":"117 ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139249291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-22DOI: 10.3390/aerospace10120980
Shao Xuan Seah, S. Srigrarom
This paper explores the use of deep reinforcement learning in solving the multi-agent aircraft traffic planning (individual paths) and collision avoidance problem for a multiple UAS, such as that for a cargo drone network. Specifically, the Deep Q-Network (DQN) with Hindsight Experience Replay framework is adopted and trained on a three-dimensional state space that represents a congested urban environment with dynamic obstacles. Through formalising a Markov decision process (MDP), various flight and control parameters are varied between training simulations to study their effects on agent performance. Both fully observable MDPs (FOMDPs) and partially observable MDPs (POMDPs) are formulated to understand the role of shaping reward signals on training performance. While conventional traffic planning and optimisation techniques are evaluated based on path length or time, this paper aims to incorporate economic analysis by considering tangible and intangible sources of cost, such as the cost of energy, the value of time (VOT) and the value of reliability (VOR). By comparing outcomes from an integration of multiple cost sources, this paper is better able to gauge the impact of various parameters on efficiency. To further explore the feasibility of multiple UAS traffic planning, such as cargo drone networks, the trained agents are also subjected to multi-agent point-to-point and hub-and-spoke network environments. In these simulations, delivery orders are generated using a discrete event simulator with an arrival rate, which is varied to investigate the effect of travel demand on economic costs. Simulation results point to the importance of signal engineering, as reward signals play a crucial role in shaping reinforcements. The results also reflect an increase in costs for environments where congestion and arrival time uncertainty arise because of the presence of other agents in the network.
{"title":"Multiple UAS Traffic Planning Based on Deep Q-Network with Hindsight Experience Replay and Economic Considerations","authors":"Shao Xuan Seah, S. Srigrarom","doi":"10.3390/aerospace10120980","DOIUrl":"https://doi.org/10.3390/aerospace10120980","url":null,"abstract":"This paper explores the use of deep reinforcement learning in solving the multi-agent aircraft traffic planning (individual paths) and collision avoidance problem for a multiple UAS, such as that for a cargo drone network. Specifically, the Deep Q-Network (DQN) with Hindsight Experience Replay framework is adopted and trained on a three-dimensional state space that represents a congested urban environment with dynamic obstacles. Through formalising a Markov decision process (MDP), various flight and control parameters are varied between training simulations to study their effects on agent performance. Both fully observable MDPs (FOMDPs) and partially observable MDPs (POMDPs) are formulated to understand the role of shaping reward signals on training performance. While conventional traffic planning and optimisation techniques are evaluated based on path length or time, this paper aims to incorporate economic analysis by considering tangible and intangible sources of cost, such as the cost of energy, the value of time (VOT) and the value of reliability (VOR). By comparing outcomes from an integration of multiple cost sources, this paper is better able to gauge the impact of various parameters on efficiency. To further explore the feasibility of multiple UAS traffic planning, such as cargo drone networks, the trained agents are also subjected to multi-agent point-to-point and hub-and-spoke network environments. In these simulations, delivery orders are generated using a discrete event simulator with an arrival rate, which is varied to investigate the effect of travel demand on economic costs. Simulation results point to the importance of signal engineering, as reward signals play a crucial role in shaping reinforcements. The results also reflect an increase in costs for environments where congestion and arrival time uncertainty arise because of the presence of other agents in the network.","PeriodicalId":48525,"journal":{"name":"Aerospace","volume":"30 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139249333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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