Pub Date : 2026-02-09DOI: 10.1016/j.ast.2026.111850
Xinrui Zhou , Hairun Xie , Bokai Li , Jing Wang , Qineng Wang , Yonghe Zhang
Topology optimization is crucial for enhancing structural performance and reducing costs in fields such as aerospace, automotive, and civil engineering. However, traditional methods face exponentially growing computational costs as mesh resolution increases. Meanwhile, existing generative models often rely on image-based representations, which limits their adaptability to components at different resolutions. To overcome these limitations, we propose NG-TO (Neural Compression-based Generative Topology Optimization), an implicit generative method that integrates neural compression with diffusion models. Our framework first encodes topologies into a compact, resolution-invariant latent space. A diffusion model then operates within this space to generate new designs that comply with specified physical constraints. Evaluations in multi-resolution and out-of-distribution scenarios demonstrate the model’s capability for resolution-free encoding and constraint satisfaction, establishing a high-performance paradigm for spacecraft structural design.
{"title":"An implicit generative topology optimization method based on neural compression and diffusion models","authors":"Xinrui Zhou , Hairun Xie , Bokai Li , Jing Wang , Qineng Wang , Yonghe Zhang","doi":"10.1016/j.ast.2026.111850","DOIUrl":"10.1016/j.ast.2026.111850","url":null,"abstract":"<div><div>Topology optimization is crucial for enhancing structural performance and reducing costs in fields such as aerospace, automotive, and civil engineering. However, traditional methods face exponentially growing computational costs as mesh resolution increases. Meanwhile, existing generative models often rely on image-based representations, which limits their adaptability to components at different resolutions. To overcome these limitations, we propose NG-TO (Neural Compression-based Generative Topology Optimization), an implicit generative method that integrates neural compression with diffusion models. Our framework first encodes topologies into a compact, resolution-invariant latent space. A diffusion model then operates within this space to generate new designs that comply with specified physical constraints. Evaluations in multi-resolution and out-of-distribution scenarios demonstrate the model’s capability for resolution-free encoding and constraint satisfaction, establishing a high-performance paradigm for spacecraft structural design.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"174 ","pages":"Article 111850"},"PeriodicalIF":5.8,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-02-09DOI: 10.1016/j.ast.2026.111785
Afsaneh Kheirani , Ilyass Tabiai , David St-Onge
Indoor inspection and mapping missions in tunnels, industrial facilities, and subterranean environments require aerial platforms capable of long-duration operation in cluttered, humid, and navigation-denied conditions. While multirotor drones provide high maneuverability, their endurance and payload capacity are fundamentally limited by battery-powered lift. Small indoor lighter-than-air vehicles alleviate this constraint through buoyancy; however, at meter-scale volumes, envelope materials become a critical limitation, as they largely determine system mass, gas retention, durability, and resistance to handling and collisions. Commonly used films present persistent trade-offs: metallized polyester offers low gas permeability but limited mechanical robustness, whereas polyurethane is more durable but heavier and more permeable.
This work introduces and experimentally validates a lightweight composite envelope material based on low-density polyethylene combined with a fluoro-siloxane barrier coating. The proposed treatment significantly improves helium retention while preserving flexibility and resistance to handling. Mechanical and functional testing show that the coated material achieves substantially higher tear resistance than metallized polyester and improved durability compared to polyurethane, while remaining considerably lighter. A cylindrical airship fabricated from this membrane was deployed in a semi-autonomous underground mapping mission, demonstrating reduced helium leakage, stable performance in humid conditions, and multi-day operation. These results show that fluoro-siloxane-coated polyethylene enables lightweight, durable, and gas-efficient envelopes, supporting persistent indoor operation of small lighter-than-air aerial platforms.
{"title":"Vehicle envelope with lightweight ultrafilm for minimal leakage (VELUM)","authors":"Afsaneh Kheirani , Ilyass Tabiai , David St-Onge","doi":"10.1016/j.ast.2026.111785","DOIUrl":"10.1016/j.ast.2026.111785","url":null,"abstract":"<div><div>Indoor inspection and mapping missions in tunnels, industrial facilities, and subterranean environments require aerial platforms capable of long-duration operation in cluttered, humid, and navigation-denied conditions. While multirotor drones provide high maneuverability, their endurance and payload capacity are fundamentally limited by battery-powered lift. Small indoor lighter-than-air vehicles alleviate this constraint through buoyancy; however, at meter-scale volumes, envelope materials become a critical limitation, as they largely determine system mass, gas retention, durability, and resistance to handling and collisions. Commonly used films present persistent trade-offs: metallized polyester offers low gas permeability but limited mechanical robustness, whereas polyurethane is more durable but heavier and more permeable.</div><div>This work introduces and experimentally validates a lightweight composite envelope material based on low-density polyethylene combined with a fluoro-siloxane barrier coating. The proposed treatment significantly improves helium retention while preserving flexibility and resistance to handling. Mechanical and functional testing show that the coated material achieves substantially higher tear resistance than metallized polyester and improved durability compared to polyurethane, while remaining considerably lighter. A cylindrical airship fabricated from this membrane was deployed in a semi-autonomous underground mapping mission, demonstrating reduced helium leakage, stable performance in humid conditions, and multi-day operation. These results show that fluoro-siloxane-coated polyethylene enables lightweight, durable, and gas-efficient envelopes, supporting persistent indoor operation of small lighter-than-air aerial platforms.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"174 ","pages":"Article 111785"},"PeriodicalIF":5.8,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The objective of this study is to propose a cross-flow fan for VTOL applications, evaluate its aerodynamic performance, and enhance its performance through a multi-objective optimization design method. Following an investigation into a three-dimensional CFD analysis approach for assessing the fan’s aerodynamic performance, a multi-objective optimization framework that simultaneously optimizes the rotor and casing by integrating CFD analysis and a deep neural network was developed and implemented. Based on CFD-derived performance metrics, the optimized fan demonstrated a thrust-shaft power ratio approximately 12.4 % lower than that of the original fan, while achieving a thrust increase of approximately 78.1 %. This substantial improvement in thrust was attributed to elevated flow velocity and flow rate at the fan outlet. Additionally, the thrust coefficient of the cross-flow fan was shown to be more than one order of magnitude greater than that of a conventional propeller fan. Performance validation using a scaled-down model further confirmed the effectiveness of the optimization method: although the thrust-shaft power ratio of the optimized fan was approximately 3.0 % lower than the original fan, its thrust increased by approximately 64.2 %. These findings underscore the potential of the proposed optimization approach not only for high-performance fan design but also for advancing the development of next-generation VTOL aircraft.
{"title":"Aerodynamic performance of a cross-flow fan for VTOL and its multi-objective optimization","authors":"Yasuyuki Nishi , Masafumi Fukuyama , Naofumi Saeki , Kotaro Ohashi , Takao Oku","doi":"10.1016/j.ast.2026.111872","DOIUrl":"10.1016/j.ast.2026.111872","url":null,"abstract":"<div><div>The objective of this study is to propose a cross-flow fan for VTOL applications, evaluate its aerodynamic performance, and enhance its performance through a multi-objective optimization design method. Following an investigation into a three-dimensional CFD analysis approach for assessing the fan’s aerodynamic performance, a multi-objective optimization framework that simultaneously optimizes the rotor and casing by integrating CFD analysis and a deep neural network was developed and implemented. Based on CFD-derived performance metrics, the optimized fan demonstrated a thrust-shaft power ratio approximately 12.4 % lower than that of the original fan, while achieving a thrust increase of approximately 78.1 %. This substantial improvement in thrust was attributed to elevated flow velocity and flow rate at the fan outlet. Additionally, the thrust coefficient of the cross-flow fan was shown to be more than one order of magnitude greater than that of a conventional propeller fan. Performance validation using a scaled-down model further confirmed the effectiveness of the optimization method: although the thrust-shaft power ratio of the optimized fan was approximately 3.0 % lower than the original fan, its thrust increased by approximately 64.2 %. These findings underscore the potential of the proposed optimization approach not only for high-performance fan design but also for advancing the development of next-generation VTOL aircraft.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"174 ","pages":"Article 111872"},"PeriodicalIF":5.8,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-02-09DOI: 10.1016/j.ast.2026.111881
Chao Tang, Yang Yan, Rongtao Wang, Zhixiong Cen, Zonghong Xie
Ice accretion poses a significant challenge to the aerodynamic performance of aircraft wings and wind turbine blades, while traditional deicing methods are hampered by high weight and energy consumption. Carbon nanotube films offer a promising alternative, yet research is lacking on their integration into high-performance, damage-tolerant hybrid laminates like GLARE (GLAss fiber REinforced aluminum) and their direct performance comparison against traditional heaters. This study, therefore, develops a novel GLARE structure with an embedded CNT film, systematically comparing its performance to an identical structure using a conventional resistance wire. The two structures were comparatively evaluated in a recirculating icing wind tunnel, using thermography and thermocouple data to assess transient thermal dynamics under ambient and cold (dry) conditions, and phenomenological deicing effectiveness under representative icing (wet) conditions. The results demonstrated the FCL(Fiber Carbon-nano Laminated) heater's superior transient performance, achieving 18.91-26.67% faster heating rates under ambient conditions and 5.13-9.23% faster rates under cold (dry) conditions, alongside significantly better thermal uniformity (ΔTmaxsof 4.6°C vs. 7.8°C). In deicing tests, the FCL heater achieved 20.00-25.86% faster deicing rates, translating to a quantified energy saving of 16.67-20.55%. Critically, the FCL heater achieved complete ice removal in 35 seconds at 15 kW/m², a performance level the RWL(Resistance Wire Laminated) heater only reached at 18 kW/m², demonstrating the FCL system can provide the same performance-on-demand with 16.67% less power input. These findings validate the significant potential of FCL heaters for efficient, lightweight deicing in next-generation aerospace and renewable energy applications.
冰积对飞机机翼和风力涡轮机叶片的气动性能提出了重大挑战，而传统的除冰方法由于重量大、能耗大而受到阻碍。碳纳米管薄膜提供了一种很有前途的替代方案，但缺乏将其集成到高性能、耐损伤的混合层压板（如眩光（玻璃纤维增强铝））中以及与传统加热器直接性能比较的研究。因此，本研究开发了一种具有嵌入式碳纳米管薄膜的新型眩光结构，并系统地将其性能与使用传统电阻丝的相同结构进行了比较。在循环结冰风洞中对两种结构进行了对比评估，利用热成像和热电偶数据评估了环境和冷（干）条件下的瞬态热动力学，以及代表性结冰（湿）条件下的现象除冰效果。结果表明，FCL（纤维碳纳米层压）加热器具有优越的瞬态性能，在环境条件下加热速度提高18.91-26.67%，在冷（干）条件下加热速度提高5.13-9.23%，同时热均匀性显著提高（ΔTmaxsof 4.6°C vs. 7.8°C）。在除冰测试中，整箱加热器的除冰率提高了20.00-25.86%，量化节能为16.67-20.55%。关键的是，FCL加热器在35秒内以15 kW/m²的速度完全除冰，而RWL（电阻丝层压）加热器的性能水平仅达到18 kW/m²，这表明FCL系统可以在减少16.67%的功率输入的情况下提供相同的性能。这些发现验证了FCL加热器在下一代航空航天和可再生能源应用中高效、轻质除冰的巨大潜力。
{"title":"Experimental investigation on improving the electro-thermal efficiency of a novel GLARE leading-edge deicing structure","authors":"Chao Tang, Yang Yan, Rongtao Wang, Zhixiong Cen, Zonghong Xie","doi":"10.1016/j.ast.2026.111881","DOIUrl":"https://doi.org/10.1016/j.ast.2026.111881","url":null,"abstract":"Ice accretion poses a significant challenge to the aerodynamic performance of aircraft wings and wind turbine blades, while traditional deicing methods are hampered by high weight and energy consumption. Carbon nanotube films offer a promising alternative, yet research is lacking on their integration into high-performance, damage-tolerant hybrid laminates like GLARE (GLAss fiber REinforced aluminum) and their direct performance comparison against traditional heaters. This study, therefore, develops a novel GLARE structure with an embedded CNT film, systematically comparing its performance to an identical structure using a conventional resistance wire. The two structures were comparatively evaluated in a recirculating icing wind tunnel, using thermography and thermocouple data to assess transient thermal dynamics under ambient and cold (dry) conditions, and phenomenological deicing effectiveness under representative icing (wet) conditions. The results demonstrated the FCL(Fiber Carbon-nano Laminated) heater's superior transient performance, achieving 18.91-26.67% faster heating rates under ambient conditions and 5.13-9.23% faster rates under cold (dry) conditions, alongside significantly better thermal uniformity (<mml:math altimg=\"si1.svg\"><mml:mrow><mml:mstyle mathvariant=\"normal\"><mml:mi>Δ</mml:mi></mml:mstyle><mml:msubsup><mml:mi>T</mml:mi><mml:mrow><mml:mi>max</mml:mi></mml:mrow><mml:mi>s</mml:mi></mml:msubsup></mml:mrow></mml:math>of 4.6°C vs. 7.8°C). In deicing tests, the FCL heater achieved 20.00-25.86% faster deicing rates, translating to a quantified energy saving of 16.67-20.55%. Critically, the FCL heater achieved complete ice removal in 35 seconds at 15 kW/m², a performance level the RWL(Resistance Wire Laminated) heater only reached at 18 kW/m², demonstrating the FCL system can provide the same performance-on-demand with 16.67% less power input. These findings validate the significant potential of FCL heaters for efficient, lightweight deicing in next-generation aerospace and renewable energy applications.","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"11 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-02-09DOI: 10.1016/j.ast.2026.111883
Qiyong Zhou, Song Lu, Hui Shi, Heping Zhang, Rui Chen
The recirculation zone flame is typical of the flame structure in aircraft nacelle. Based on a transient extinguishing agent injection experiment apparatus, the combustion and extinguishing of recirculation zone flame under the influence of blockage ratio and wind velocity were studied, and the fire extinguishing concentration in free flow and recirculation zone were measured. A modeling study was conducted on the dynamic evolution of the flame in the recirculation zone. The critical extinguishing concentration, fire extinguishing time, and characteristic mixing time (τ) were determined and correlated with flow parameters. Results show that obstacles increase local concentrations but also stabilize flames, raising the extinction threshold. Through analysis of the mean flame length, a dynamic evolution prediction model suitable for the mean flame length in the recirculation zone has been established. A revised correlation for τ was obtained, , which exceeds values reported under non-combustion conditions and highlights the stronger coupling between mixing and reactive processes. Application to aircraft nacelle scenarios indicates that, due to short discharge durations and obstruction effects, the required free flow concentration of HFC-125 exceeds nominal design specifications to ensure effective suppression in recirculation zones. This methodology provides a quantitative basis for performance evaluation of HFC-125 systems in safety-critical applications, supporting system safety assessments during early design and certification stages.
{"title":"Fire suppression of recirculation zone flames in aircraft nacelles: effects of blockage ratio and crossflow on extinction thresholds and mixing time","authors":"Qiyong Zhou, Song Lu, Hui Shi, Heping Zhang, Rui Chen","doi":"10.1016/j.ast.2026.111883","DOIUrl":"10.1016/j.ast.2026.111883","url":null,"abstract":"<div><div>The recirculation zone flame is typical of the flame structure in aircraft nacelle. Based on a transient extinguishing agent injection experiment apparatus, the combustion and extinguishing of recirculation zone flame under the influence of blockage ratio and wind velocity were studied, and the fire extinguishing concentration in free flow and recirculation zone were measured. A modeling study was conducted on the dynamic evolution of the flame in the recirculation zone. The critical extinguishing concentration, fire extinguishing time, and characteristic mixing time (<em>τ</em>) were determined and correlated with flow parameters. Results show that obstacles increase local concentrations but also stabilize flames, raising the extinction threshold. Through analysis of the mean flame length, a dynamic evolution prediction model suitable for the mean flame length in the recirculation zone has been established. A revised correlation for <em>τ</em> was obtained, <span><math><mrow><mi>τ</mi><mo>=</mo><mn>36.6</mn><mo>(</mo><mrow><msub><mi>h</mi><mi>s</mi></msub><mo>/</mo><msubsup><mi>U</mi><mi>a</mi><mo>*</mo></msubsup></mrow><mo>)</mo></mrow></math></span>, which exceeds values reported under non-combustion conditions and highlights the stronger coupling between mixing and reactive processes. Application to aircraft nacelle scenarios indicates that, due to short discharge durations and obstruction effects, the required free flow concentration of HFC-125 exceeds nominal design specifications to ensure effective suppression in recirculation zones. This methodology provides a quantitative basis for performance evaluation of HFC-125 systems in safety-critical applications, supporting system safety assessments during early design and certification stages.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"174 ","pages":"Article 111883"},"PeriodicalIF":5.8,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-02-09DOI: 10.1016/j.ast.2026.111885
Long Zhang, Wenlin Liao, Bowen Liu, Song Feng, Juntao Fan
This paper conducts experimental investigation and multi-scale simulation for the thermal-vibration characteristics of lattice-structured air rudders, aiming to provide a comprehensive understanding of how these complex structures behave under combined thermal and vibration loads. Firstly, a quartz infrared radiation heater device with independent control tunnels is designed and fabricated to produce thermal gradient loads on the air rudder in accordance with flight service condition. On this basis, thermal model test is performed on the rudder. In order to simulate the thermal-vibration behaviour, an orthotropic temperature-dependent material model is established, where in-situ samples of different directions have been printed simultaneously with the rudder and tested under various temperature conditions to fit the material model parameters. Afterwards, a multi-scale simulation method, which is capable of linking the mesoscopic lattice structures with the macroscopic material properties, is developed to simulate the thermal model test. The maximum absolute relative error between the simulated and tested natural frequencies is within 5.0%, and the simulated and tested mode shapes are in good agreement with each other, which proves that the developed method possesses good capability for computing natural frequencies and mode shapes of the lattice-structured air rudder under complicated thermal conditions. This combined approach enables a more thorough investigation of the thermal-vibration characteristics, leading to improved design and performance of lattice-structured air rudders.
{"title":"Thermal model test and multi-scale simulation method for the lattice-structured air rudder of hypersonic flight vehicle","authors":"Long Zhang, Wenlin Liao, Bowen Liu, Song Feng, Juntao Fan","doi":"10.1016/j.ast.2026.111885","DOIUrl":"10.1016/j.ast.2026.111885","url":null,"abstract":"<div><div>This paper conducts experimental investigation and multi-scale simulation for the thermal-vibration characteristics of lattice-structured air rudders, aiming to provide a comprehensive understanding of how these complex structures behave under combined thermal and vibration loads. Firstly, a quartz infrared radiation heater device with independent control tunnels is designed and fabricated to produce thermal gradient loads on the air rudder in accordance with flight service condition. On this basis, thermal model test is performed on the rudder. In order to simulate the thermal-vibration behaviour, an orthotropic temperature-dependent material model is established, where in-situ samples of different directions have been printed simultaneously with the rudder and tested under various temperature conditions to fit the material model parameters. Afterwards, a multi-scale simulation method, which is capable of linking the mesoscopic lattice structures with the macroscopic material properties, is developed to simulate the thermal model test. The maximum absolute relative error between the simulated and tested natural frequencies is within 5.0%, and the simulated and tested mode shapes are in good agreement with each other, which proves that the developed method possesses good capability for computing natural frequencies and mode shapes of the lattice-structured air rudder under complicated thermal conditions. This combined approach enables a more thorough investigation of the thermal-vibration characteristics, leading to improved design and performance of lattice-structured air rudders.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"174 ","pages":"Article 111885"},"PeriodicalIF":5.8,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-02-09DOI: 10.1016/j.ast.2026.111880
ZeYang Xiao, Bijiao He, Lihui Liu, Yatao Chen, Kuo Li, Guobiao Cai
The exhaust plume ejected from a rocket engine exhibits high temperature and pressure, leading to intense infrared radiation signals. Variations in expansion ratio and ambient pressure influence the plume’s flow field structure, which in turn affects these signals. This study investigates the effects of the expansion ratio, which ranges from under-expanded (2.78) to the optimal state (5.65), and the flight altitude, varying from 0 km to 30 km, on the flow field and infrared radiation (IR) characteristics of the exhaust plume. The exhaust plume flow field is numerically solved using the Computational Fluid Dynamics (CFD) method, while its radiative transfer is modeled using the Backward Monte Carlo method. Additionally, the gas radiative properties in the radiative transfer process are computed using the line-by-line method. The simulation results show that plume diffusion increases significantly with altitude, but it is less sensitive to changes in expansion ratios at a given altitude. At the lower altitudes, such as 0 km and 5 km, the difference in total radiation intensity due to varying expansion ratios is minimal. However, as altitude increases, the disparity in total radiation intensity among different expansion ratios grows noticeably. At an altitude of 30 km, the radiation increment caused by the expansion ratio exceeds threefold compared to that at 0 km. This is attributed to the smaller expansion ratio intensifying the afterburning reactions and promoting the formation of strongly radiative species, such as H2O and CO2.
{"title":"Analysis of the effects of expansion ratio on the structure and infrared radiation characteristics of engine under-expanded plume under different altitudes","authors":"ZeYang Xiao, Bijiao He, Lihui Liu, Yatao Chen, Kuo Li, Guobiao Cai","doi":"10.1016/j.ast.2026.111880","DOIUrl":"https://doi.org/10.1016/j.ast.2026.111880","url":null,"abstract":"The exhaust plume ejected from a rocket engine exhibits high temperature and pressure, leading to intense infrared radiation signals. Variations in expansion ratio and ambient pressure influence the plume’s flow field structure, which in turn affects these signals. This study investigates the effects of the expansion ratio, which ranges from under-expanded (2.78) to the optimal state (5.65), and the flight altitude, varying from 0 km to 30 km, on the flow field and infrared radiation (IR) characteristics of the exhaust plume. The exhaust plume flow field is numerically solved using the Computational Fluid Dynamics (CFD) method, while its radiative transfer is modeled using the Backward Monte Carlo method. Additionally, the gas radiative properties in the radiative transfer process are computed using the line-by-line method. The simulation results show that plume diffusion increases significantly with altitude, but it is less sensitive to changes in expansion ratios at a given altitude. At the lower altitudes, such as 0 km and 5 km, the difference in total radiation intensity due to varying expansion ratios is minimal. However, as altitude increases, the disparity in total radiation intensity among different expansion ratios grows noticeably. At an altitude of 30 km, the radiation increment caused by the expansion ratio exceeds threefold compared to that at 0 km. This is attributed to the smaller expansion ratio intensifying the afterburning reactions and promoting the formation of strongly radiative species, such as H<ce:inf loc=\"post\">2</ce:inf>O and CO<ce:inf loc=\"post\">2</ce:inf>.","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"91 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Endwall cross flow is a critical factor in inducing corner separation in compressors, substantially influencing their aerodynamic performance. To address this issue at its source, this study investigates the application of vortex generators (VGs) to the endwall of the compressor cascade passage, positioned between the leading and trailing edges. Two configurations—single VG and double VG—are designed and analyzed. Using a combination of experimental and numerical methods, the study evaluates the effectiveness of the endwall passage VG technique in mitigating endwall cross flow and controlling corner separation. In addition, it uncovers the underlying flow control mechanisms and provides design guidelines. Experimental results show that both the single VG and double VG schemes effectively suppress endwall cross flow near the suction side of the compressor cascade, thereby controlling corner separation and markedly enhancing aerodynamic performance. Under an inlet Mach number of 0.6 and an incidence angle of −7°, the single VG scheme reduces the total pressure loss coefficient of the compressor cascade by 9.0%. The success of the endwall passage VG technique lies in its dual action: the direct blocking effect of the VG on the endwall cross flow, and the suppression of endwall cross flow by the concentrated vortex it generates. Together, these mechanisms constitute the key to effectively controlling corner separation in compressor cascades. Moreover, this concentrated vortex further weakens the passage vortex, thereby improving the endwall flow field.
{"title":"Compressor cascade cross flow control via endwall passage vortex generator","authors":"Huiling Zhu, Ling Zhou, Xin Li, Chenhao Zhao, Tongtong Meng, Lucheng Ji","doi":"10.1016/j.ast.2026.111888","DOIUrl":"https://doi.org/10.1016/j.ast.2026.111888","url":null,"abstract":"Endwall cross flow is a critical factor in inducing corner separation in compressors, substantially influencing their aerodynamic performance. To address this issue at its source, this study investigates the application of vortex generators (VGs) to the endwall of the compressor cascade passage, positioned between the leading and trailing edges. Two configurations—single VG and double VG—are designed and analyzed. Using a combination of experimental and numerical methods, the study evaluates the effectiveness of the endwall passage VG technique in mitigating endwall cross flow and controlling corner separation. In addition, it uncovers the underlying flow control mechanisms and provides design guidelines. Experimental results show that both the single VG and double VG schemes effectively suppress endwall cross flow near the suction side of the compressor cascade, thereby controlling corner separation and markedly enhancing aerodynamic performance. Under an inlet Mach number of 0.6 and an incidence angle of −7°, the single VG scheme reduces the total pressure loss coefficient of the compressor cascade by 9.0%. The success of the endwall passage VG technique lies in its dual action: the direct blocking effect of the VG on the endwall cross flow, and the suppression of endwall cross flow by the concentrated vortex it generates. Together, these mechanisms constitute the key to effectively controlling corner separation in compressor cascades. Moreover, this concentrated vortex further weakens the passage vortex, thereby improving the endwall flow field.","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"245 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Owing to its computational efficiency in gradient evaluation, the adjoint method has emerged as a cornerstone in the field of aerodynamic shape optimization. However, the efficiency of the adjoint-based aerodynamic shape optimization relies on the cost of solving adjoint equations, which still remains time-consuming. In this paper, the adjoint method is accelerated by constructing efficient dynamic Reduced-Order Models (ROMs) enhanced by the active learning strategy. During each adjoint optimization step, the query function, i.e., also the objective function, is introduced to obtain relevant additional samples for updating the dynamic ROM. The updated ROM then predicts an improved initial guess for the adjoint solver, enabling faster convergence and accelerating the overall optimization process. The proposed Active Learning ADjoint (ALAD) method does not require additional simulation for model update, and is easy to combine with other acceleration methods. The efficiency of the proposed method is verified by airfoil shape optimization in both transonic inviscid and subsonic laminar flow regimes. Results indicate that the proposed ROM significantly reduces the initial residual of pseudo-time iterations, thus significantly decreasing the iteration numbers required by adjoint optimization. Finally, we combine ALAD with the dynamic mode decomposition (DMD) acceleration method, showing that this approach can be combined with other methods to further enhance the optimization efficiency. The proposed method holds great promise for a wide range of applications in aerospace engineering.
{"title":"Accelerating adjoint-based aerodynamic shape optimization through integrating reduced-order modeling and active learning","authors":"Wengang Chen, Weixiang Gao, Jiaqing Kou, Wenkai Yang, Hongyu Zheng, Baoling Lu","doi":"10.1016/j.ast.2026.111876","DOIUrl":"https://doi.org/10.1016/j.ast.2026.111876","url":null,"abstract":"Owing to its computational efficiency in gradient evaluation, the adjoint method has emerged as a cornerstone in the field of aerodynamic shape optimization. However, the efficiency of the adjoint-based aerodynamic shape optimization relies on the cost of solving adjoint equations, which still remains time-consuming. In this paper, the adjoint method is accelerated by constructing efficient dynamic Reduced-Order Models (ROMs) enhanced by the active learning strategy. During each adjoint optimization step, the query function, i.e., also the objective function, is introduced to obtain relevant additional samples for updating the dynamic ROM. The updated ROM then predicts an improved initial guess for the adjoint solver, enabling faster convergence and accelerating the overall optimization process. The proposed Active Learning ADjoint (ALAD) method does not require additional simulation for model update, and is easy to combine with other acceleration methods. The efficiency of the proposed method is verified by airfoil shape optimization in both transonic inviscid and subsonic laminar flow regimes. Results indicate that the proposed ROM significantly reduces the initial residual of pseudo-time iterations, thus significantly decreasing the iteration numbers required by adjoint optimization. Finally, we combine ALAD with the dynamic mode decomposition (DMD) acceleration method, showing that this approach can be combined with other methods to further enhance the optimization efficiency. The proposed method holds great promise for a wide range of applications in aerospace engineering.","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"48 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2026-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号