Pub Date : 2025-02-11DOI: 10.1016/j.ast.2025.110050
Ying Zhou , Yuanxin Li , Zhongsheng Hou , Choon Ki Ahn
This paper aims to address the event-triggered optimized attitude consensus tracking control problem for multiple spacecraft with prescribed setting time. To ensure the convergence of the consensus tracking error within a prescribed time, a transformation function is constructed by using a time-varying constraining function related to the prescribed time and accuracy. To optimize control performance, a class of Hamilton-Jacobi-Bellman (HJB) equations are constructed to derive a reinforcement learning (RL)-based optimal control law, where the fuzzy logic system (FLS) is employed to approximate the optimal solution within the actor-critic architecture. In addition, the dynamic event-triggered mechanism is adopted for the controller to decrease communication resource utilization. Based on the Lyapunov stability analysis, the consensus tracking error is proved to be semi-globally uniformly ultimately bounded (SGUUB) with adjustable error bounds. Finally, a simulation example is given to demonstrate the effectiveness of the proposed method.
{"title":"Dynamic event-triggered prescribed-time optimized backstepping attitude consensus tracking control for multiple spacecrafts","authors":"Ying Zhou , Yuanxin Li , Zhongsheng Hou , Choon Ki Ahn","doi":"10.1016/j.ast.2025.110050","DOIUrl":"10.1016/j.ast.2025.110050","url":null,"abstract":"<div><div>This paper aims to address the event-triggered optimized attitude consensus tracking control problem for multiple spacecraft with prescribed setting time. To ensure the convergence of the consensus tracking error within a prescribed time, a transformation function is constructed by using a time-varying constraining function related to the prescribed time and accuracy. To optimize control performance, a class of Hamilton-Jacobi-Bellman (HJB) equations are constructed to derive a reinforcement learning (RL)-based optimal control law, where the fuzzy logic system (FLS) is employed to approximate the optimal solution within the actor-critic architecture. In addition, the dynamic event-triggered mechanism is adopted for the controller to decrease communication resource utilization. Based on the Lyapunov stability analysis, the consensus tracking error is proved to be semi-globally uniformly ultimately bounded (SGUUB) with adjustable error bounds. Finally, a simulation example is given to demonstrate the effectiveness of the proposed method.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"160 ","pages":"Article 110050"},"PeriodicalIF":5.0,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143402743","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 : 2025-02-10DOI: 10.1016/j.ast.2025.110045
Jinyi Ma, Qianqian Zhu, Tao Xue, Jianliang Ai, Yiqun Dong
Aircraft dynamics modeling is an important part of advanced control law design and flight safety. To address the challenge of longitudinal dynamics modeling using a small amount of flight test data under high-angle-of-attack (AOA) conditions, we propose an effective approach that integrates machine learning with physical mechanisms. First, a low-fidelity aircraft dynamics model based on physical analysis is established. Second, a Residual Transformer (ResTrans) autoencoder is designed to extract temporal and spatial features from flight motion history under high-AOA conditions. These features are then used to compensate for the modeling errors of the low-fidelity model through a deep neural network (DNN)-based fusion module, resulting in a high-fidelity aircraft dynamics model. Moreover, a physics-informed closed-loop multi-step dynamics evolution (PI-CMDE) paradigm is developed for constructing loss functions, ensuring stable and efficient parameter optimization of the high-fidelity model. Finally, a simulation model of a scaled F-16 aircraft is used to generate a small set of high-AOA flight test data for training and testing the high-fidelity model. Experimental results demonstrate that, compared to three representative aircraft dynamics modeling baseline methods, the proposed approach achieves higher modeling accuracy and better generalization performance, highlighting its advanced capabilities.
{"title":"Aircraft dynamics modeling at high angle of attack incorporating residual transformer autoencoder and physical mechanisms","authors":"Jinyi Ma, Qianqian Zhu, Tao Xue, Jianliang Ai, Yiqun Dong","doi":"10.1016/j.ast.2025.110045","DOIUrl":"10.1016/j.ast.2025.110045","url":null,"abstract":"<div><div>Aircraft dynamics modeling is an important part of advanced control law design and flight safety. To address the challenge of longitudinal dynamics modeling using a small amount of flight test data under high-angle-of-attack (AOA) conditions, we propose an effective approach that integrates machine learning with physical mechanisms. First, a low-fidelity aircraft dynamics model based on physical analysis is established. Second, a Residual Transformer (ResTrans) autoencoder is designed to extract temporal and spatial features from flight motion history under high-AOA conditions. These features are then used to compensate for the modeling errors of the low-fidelity model through a deep neural network (DNN)-based fusion module, resulting in a high-fidelity aircraft dynamics model. Moreover, a physics-informed closed-loop multi-step dynamics evolution (PI-CMDE) paradigm is developed for constructing loss functions, ensuring stable and efficient parameter optimization of the high-fidelity model. Finally, a simulation model of a scaled F-16 aircraft is used to generate a small set of high-AOA flight test data for training and testing the high-fidelity model. Experimental results demonstrate that, compared to three representative aircraft dynamics modeling baseline methods, the proposed approach achieves higher modeling accuracy and better generalization performance, highlighting its advanced capabilities.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"160 ","pages":"Article 110045"},"PeriodicalIF":5.0,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143402742","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}
To address the complex issues of discontinuous disturbances, parameter uncertainties, actuator deadzone, and saturation nonlinearity in Variable Swept-Wing Near Space Vehicles (NSV), an attitude controller combining reinforcement learning and adaptive switching sliding mode control is proposed, along with an adaptive threshold event-triggered mechanism to reduce the actuator executing frequency. Firstly, the motion characteristics of the Variable Swept-Wing NSV across the full range of operating modes are modeled as a nonlinear switched system. Secondly, a nonlinear switched disturbance observer is employed to estimate the composite disturbances caused by discontinuous disturbances and parameter uncertainties. By introducing a deadzone right inverse function and designing an auxiliary system, the composite nonlinearity of the actuator are effectively addressed. An adaptive multi-modal switching sliding mode controller is then proposed based on the backstepping method to achieve basic control. Subsequently, considering the higher dimensionality of aerodynamic control surfaces and the increased complexity of aerodynamic characteristics in the subsonic mode, which imposes stricter control requirements, a reinforcement learning-based controller is designed. Leveraging the self-learning and optimization capabilities of reinforcement learning, which does not rely on an accurate model, the controller achieves end-to-end control of the horizontal canard. Finally, an event-triggered mechanism with an adaptively varying threshold is also developed. The multi-Lyapunov stability theory and the average dwell-time theory are employed to guarantee the stability of the closed-loop nonlinear switched system while excluding the undesired Zeno behavior. Simulations and comparative experiments demonstrate that the proposed method achieves superior tracking accuracy and control performance, while the adaptive threshold event-triggered mechanism effectively reduces data transmission.
{"title":"Attitude control of variable swept-wing aircraft: A novel composite control strategy","authors":"Xiaoming Chen, Lisha Meng, Jiaji Liu, Danqing Shen","doi":"10.1016/j.ast.2025.110043","DOIUrl":"10.1016/j.ast.2025.110043","url":null,"abstract":"<div><div>To address the complex issues of discontinuous disturbances, parameter uncertainties, actuator deadzone, and saturation nonlinearity in Variable Swept-Wing Near Space Vehicles (NSV), an attitude controller combining reinforcement learning and adaptive switching sliding mode control is proposed, along with an adaptive threshold event-triggered mechanism to reduce the actuator executing frequency. Firstly, the motion characteristics of the Variable Swept-Wing NSV across the full range of operating modes are modeled as a nonlinear switched system. Secondly, a nonlinear switched disturbance observer is employed to estimate the composite disturbances caused by discontinuous disturbances and parameter uncertainties. By introducing a deadzone right inverse function and designing an auxiliary system, the composite nonlinearity of the actuator are effectively addressed. An adaptive multi-modal switching sliding mode controller is then proposed based on the backstepping method to achieve basic control. Subsequently, considering the higher dimensionality of aerodynamic control surfaces and the increased complexity of aerodynamic characteristics in the subsonic mode, which imposes stricter control requirements, a reinforcement learning-based controller is designed. Leveraging the self-learning and optimization capabilities of reinforcement learning, which does not rely on an accurate model, the controller achieves end-to-end control of the horizontal canard. Finally, an event-triggered mechanism with an adaptively varying threshold is also developed. The multi-Lyapunov stability theory and the average dwell-time theory are employed to guarantee the stability of the closed-loop nonlinear switched system while excluding the undesired Zeno behavior. Simulations and comparative experiments demonstrate that the proposed method achieves superior tracking accuracy and control performance, while the adaptive threshold event-triggered mechanism effectively reduces data transmission.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"160 ","pages":"Article 110043"},"PeriodicalIF":5.0,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143418961","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 : 2025-02-10DOI: 10.1016/j.ast.2025.110042
Xinyu Chen , Yunsheng Fan , Guofeng Wang , Dongdong Mu
Quadrotor slung-load (QSL) systems are commonly employed in aerial transportation tasks, where precise trajectory tracking and effective load swing suppression are critical challenges. These objectives are challenged by model uncertainties and unknown environmental disturbances, such as wind, which can compromise system stability and control accuracy. This paper addresses these challenges by developing a novel control strategy for QSL systems, where the system dynamics are divided into the attitude, position, and swing angle of the slung-load. Wind disturbances, including turbulence and wind shear, are modeled to simulate realistic outdoor scenarios. The integration backstepping control method forms the basis of the controller design, the sliding mode control is added to enhance the control accuracy and robustness while reducing steady-state error. An improved extended disturbance observer (IEDO) is incorporated to estimate and compensate for unknown disturbances and model uncertainties. The stability of the proposed controller and the convergence of the disturbance observer are rigorously analyzed using Lyapunov theory. Simulation results demonstrate the effectiveness of the proposed approach, achieving significant reductions in trajectory tracking errors and slung-load swing, even under complex and varying disturbance conditions.
{"title":"Improved extended disturbance observer-based integral backstepping sliding mode control for quadrotor slung-load system","authors":"Xinyu Chen , Yunsheng Fan , Guofeng Wang , Dongdong Mu","doi":"10.1016/j.ast.2025.110042","DOIUrl":"10.1016/j.ast.2025.110042","url":null,"abstract":"<div><div>Quadrotor slung-load (QSL) systems are commonly employed in aerial transportation tasks, where precise trajectory tracking and effective load swing suppression are critical challenges. These objectives are challenged by model uncertainties and unknown environmental disturbances, such as wind, which can compromise system stability and control accuracy. This paper addresses these challenges by developing a novel control strategy for QSL systems, where the system dynamics are divided into the attitude, position, and swing angle of the slung-load. Wind disturbances, including turbulence and wind shear, are modeled to simulate realistic outdoor scenarios. The integration backstepping control method forms the basis of the controller design, the sliding mode control is added to enhance the control accuracy and robustness while reducing steady-state error. An improved extended disturbance observer (IEDO) is incorporated to estimate and compensate for unknown disturbances and model uncertainties. The stability of the proposed controller and the convergence of the disturbance observer are rigorously analyzed using Lyapunov theory. Simulation results demonstrate the effectiveness of the proposed approach, achieving significant reductions in trajectory tracking errors and slung-load swing, even under complex and varying disturbance conditions.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"160 ","pages":"Article 110042"},"PeriodicalIF":5.0,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387895","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 : 2025-02-10DOI: 10.1016/j.ast.2025.110037
David Massegur, Andrea Da Ronch
Deep learning technologies are increasingly used in various applications, with significant potential in aerospace for reduced-order modelling due to their ability to handle nonlinear systems. The effectiveness of data-driven methods relies on the adequacy and volume of training data, which poses a challenge in a design environment. To address this, physics-informed machine learning, which integrates physics knowledge into data-driven frameworks, has emerged as a promising solution. Directly applying physics terms to aircraft surfaces is complex, so this study utilizes solution gradients to effectively capture flow features. We introduce a hybrid framework that combines geometric deep learning with gradient terms, building on a previous data-driven approach for aerodynamic modelling on large-scale, three-dimensional unstructured grids. We evaluated various hybrid schemes to enhance prediction accuracy. Two gradient-enhanced approaches were found to outperform the purely data-driven model: the first integrates output differentiation into the training loss, achieving the highest accuracy at an increased training cost; the second employs a masking technique to weight regions with large gradients, providing a reasonable accuracy improvement at a lower training cost. This study focuses on predicting distributed aerodynamic loads around the NASA Common Research Model wing/body configuration under various transonic flight conditions. Our findings show that incorporating gradient information into deep learning models significantly improves the accuracy of the predictions and can compensate for a smaller dataset without compromising accuracy. Furthermore, the approaches proposed herein are directly applicable to any problem with discretised spatial domain.
{"title":"Augmenting mesh-based data-driven models with physics gradients","authors":"David Massegur, Andrea Da Ronch","doi":"10.1016/j.ast.2025.110037","DOIUrl":"10.1016/j.ast.2025.110037","url":null,"abstract":"<div><div>Deep learning technologies are increasingly used in various applications, with significant potential in aerospace for reduced-order modelling due to their ability to handle nonlinear systems. The effectiveness of data-driven methods relies on the adequacy and volume of training data, which poses a challenge in a design environment. To address this, physics-informed machine learning, which integrates physics knowledge into data-driven frameworks, has emerged as a promising solution. Directly applying physics terms to aircraft surfaces is complex, so this study utilizes solution gradients to effectively capture flow features. We introduce a hybrid framework that combines geometric deep learning with gradient terms, building on a previous data-driven approach for aerodynamic modelling on large-scale, three-dimensional unstructured grids. We evaluated various hybrid schemes to enhance prediction accuracy. Two gradient-enhanced approaches were found to outperform the purely data-driven model: the first integrates output differentiation into the training loss, achieving the highest accuracy at an increased training cost; the second employs a masking technique to weight regions with large gradients, providing a reasonable accuracy improvement at a lower training cost. This study focuses on predicting distributed aerodynamic loads around the NASA Common Research Model wing/body configuration under various transonic flight conditions. Our findings show that incorporating gradient information into deep learning models significantly improves the accuracy of the predictions and can compensate for a smaller dataset without compromising accuracy. Furthermore, the approaches proposed herein are directly applicable to any problem with discretised spatial domain.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"160 ","pages":"Article 110037"},"PeriodicalIF":5.0,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-10DOI: 10.1016/j.ast.2025.110039
Shunhao Peng , Yongliang Feng , Xiaojing Zheng
Radio communication blackout is one of the most significant obstacles to the operation and telemetry of hypersonic vehicles. The plasma manipulation with a pulsed magnetic field has been identified as a promising solution to the blackout problem through laboratory observations. To evaluate the effect of the pulsed magnetic field in realistic hypersonic flight conditions, this work numerically studies pulsed magnetic field manipulation for the plasma layer of hypersonic vehicles based on the magnetohydrodynamic model coupled with the high-temperature gas effect. The Wentzel-Kramer-Brillouin (WKB) method is used to analyze the transmission characteristics of electromagnetic waves in a magnetized plasma. The numerical results show that the pulsed magnetic field with suitable pulse duration can reduce electron density and radio attenuation near the antenna. The communication window created by the pulsed magnetic field allows lower-frequency radio to transmit through the plasma layer and the duration of the window can last more than 0.1 ms. Besides, the effect of blackout mitigation by the pulsed magnetic field is significantly enhanced with increasing magnetic field strength at each flight altitude. These investigations can provide useful information for designing and optimizing electromagnetic manipulation for blackout mitigation.
{"title":"Numerical study on plasma layer manipulation for blackout mitigation by pulsed magnetic field","authors":"Shunhao Peng , Yongliang Feng , Xiaojing Zheng","doi":"10.1016/j.ast.2025.110039","DOIUrl":"10.1016/j.ast.2025.110039","url":null,"abstract":"<div><div>Radio communication blackout is one of the most significant obstacles to the operation and telemetry of hypersonic vehicles. The plasma manipulation with a pulsed magnetic field has been identified as a promising solution to the blackout problem through laboratory observations. To evaluate the effect of the pulsed magnetic field in realistic hypersonic flight conditions, this work numerically studies pulsed magnetic field manipulation for the plasma layer of hypersonic vehicles based on the magnetohydrodynamic model coupled with the high-temperature gas effect. The Wentzel-Kramer-Brillouin (WKB) method is used to analyze the transmission characteristics of electromagnetic waves in a magnetized plasma. The numerical results show that the pulsed magnetic field with suitable pulse duration can reduce electron density and radio attenuation near the antenna. The communication window created by the pulsed magnetic field allows lower-frequency radio to transmit through the plasma layer and the duration of the window can last more than 0.1 ms. Besides, the effect of blackout mitigation by the pulsed magnetic field is significantly enhanced with increasing magnetic field strength at each flight altitude. These investigations can provide useful information for designing and optimizing electromagnetic manipulation for blackout mitigation.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"160 ","pages":"Article 110039"},"PeriodicalIF":5.0,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387896","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 : 2025-02-09DOI: 10.1016/j.ast.2025.110033
Jun-xue Leng, Zan Xie, Wei Huang, Yang Shen, Zhen-guo Wang
Multistage waverider vehicles based on the combined trajectory flight possess aerodynamic performance advantages, offer more flexible trajectories, and can achieve extended ranges. However, current multistage waverider design technology remains underdeveloped and is still in the preliminary theoretical research stage. This paper extends the design methodology for two-stage waverider vehicles, enabling the design of a first-stage wide-speed-range waverider that conforms to the leading edge of a given irregular second-stage airbreathing lifting-body configuration, thus forming a two-stage waverider structure. According to the specific optimization requirements, we refined the multi-fidelity data-mining-based MDO (Multidisciplinary Design Optimization) framework, yielding an optimized first-stage wide-speed-range lifting body configuration with superior performance under viscous conditions. Compared with the initial configuration, the optimized first-stage vehicle, with a constant takeoff mass, achieved a 5.84 % increase in range for the boost-glide combined trajectory, further verifying the effectiveness and flexibility of the multi-fidelity data-mining-based MDO framework.
{"title":"Multidisciplinary design optimization of the first-stage waverider based on boost-glide flight trajectory","authors":"Jun-xue Leng, Zan Xie, Wei Huang, Yang Shen, Zhen-guo Wang","doi":"10.1016/j.ast.2025.110033","DOIUrl":"10.1016/j.ast.2025.110033","url":null,"abstract":"<div><div>Multistage waverider vehicles based on the combined trajectory flight possess aerodynamic performance advantages, offer more flexible trajectories, and can achieve extended ranges. However, current multistage waverider design technology remains underdeveloped and is still in the preliminary theoretical research stage. This paper extends the design methodology for two-stage waverider vehicles, enabling the design of a first-stage wide-speed-range waverider that conforms to the leading edge of a given irregular second-stage airbreathing lifting-body configuration, thus forming a two-stage waverider structure. According to the specific optimization requirements, we refined the multi-fidelity data-mining-based MDO (Multidisciplinary Design Optimization) framework, yielding an optimized first-stage wide-speed-range lifting body configuration with superior performance under viscous conditions. Compared with the initial configuration, the optimized first-stage vehicle, with a constant takeoff mass, achieved a 5.84 % increase in range for the boost-glide combined trajectory, further verifying the effectiveness and flexibility of the multi-fidelity data-mining-based MDO framework.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"160 ","pages":"Article 110033"},"PeriodicalIF":5.0,"publicationDate":"2025-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143378773","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 : 2025-02-08DOI: 10.1016/j.ast.2025.110047
Zhiyuan Zhao , Fengbo Wen , Zuobiao Li , Jiajun Han , Yu Li , Xinghong Zhang , Songtao Wang
Film cooling holes embedded in craters or trenches are gaining attention as recent advancements in gas turbines due to significant improvements in film cooling effectiveness. Inspired by ginkgo leaves, a novel ginkgo-shape film cooling crater with two spreading lobes has been investigated using large eddy simulation (LES), achieving considerable enhancements in film cooling performance. A comprehensive evaluation of coolant film distribution and vortical structure variation is illustrated to understand the flow dynamics of compound cooling jets emerging from cooling holes embedded in the ginkgo craters at the blowing ratio of M = 1.0 and the density ratio of DR = 2.0. The film cooling effectiveness is greatly improved with compound angles of 0 deg and 30 deg due to the wide lateral expansion of coolant film and less coolant separation in the streamwise direction. However, the ginkgo crater deteriorates the cooling performance with a compound angle of 60 deg because of the enlarged uncooled gap between the adjacent holes. Instantaneous and time-averaged vortical structures are examined, showing that the upwash counter-rotating vortex pair (CRVP) and the asymmetric vortex (ASV) are greatly weakened. The origination and evolvement of the shear layer vortex and the hairpin vortex are discussed in detail with the effect of the ginkgo crater in the current work.
{"title":"Large eddy simulation of compound angle film cooling with round holes embedded in ginkgo-shaped craters","authors":"Zhiyuan Zhao , Fengbo Wen , Zuobiao Li , Jiajun Han , Yu Li , Xinghong Zhang , Songtao Wang","doi":"10.1016/j.ast.2025.110047","DOIUrl":"10.1016/j.ast.2025.110047","url":null,"abstract":"<div><div>Film cooling holes embedded in craters or trenches are gaining attention as recent advancements in gas turbines due to significant improvements in film cooling effectiveness. Inspired by ginkgo leaves, a novel ginkgo-shape film cooling crater with two spreading lobes has been investigated using large eddy simulation (LES), achieving considerable enhancements in film cooling performance. A comprehensive evaluation of coolant film distribution and vortical structure variation is illustrated to understand the flow dynamics of compound cooling jets emerging from cooling holes embedded in the ginkgo craters at the blowing ratio of <em>M</em> = 1.0 and the density ratio of DR = 2.0. The film cooling effectiveness is greatly improved with compound angles of 0 deg and 30 deg due to the wide lateral expansion of coolant film and less coolant separation in the streamwise direction. However, the ginkgo crater deteriorates the cooling performance with a compound angle of 60 deg because of the enlarged uncooled gap between the adjacent holes. Instantaneous and time-averaged vortical structures are examined, showing that the upwash counter-rotating vortex pair (CRVP) and the asymmetric vortex (ASV) are greatly weakened. The origination and evolvement of the shear layer vortex and the hairpin vortex are discussed in detail with the effect of the ginkgo crater in the current work.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"160 ","pages":"Article 110047"},"PeriodicalIF":5.0,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143402509","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 : 2025-02-08DOI: 10.1016/j.ast.2025.110040
Xiaochen Mao , Fu Lei , Yunyu Wang , Zhihua Ding , Hao Cheng , Bo Liu
To investigate the load split (LS) effects on the performance and flow mechanisms of a cantilevered tandem stator in a highly loaded micro axial compressor, three typical tandem blade schemes were thoroughly studied from multiple perspectives using steady-state numerical simulations. The results show that in the LS design of the tandem blades, the trade-off effects between highly and lowly loaded conditions are essential to achieve superior overall performance. The gap jet serves a pivotal function in leakage flow behaviors, acting as a vital link between the leakage flow from the front blade (FB) and rear blade (RB). Furthermore, the mixing effects between the front blade wake and gap jet is one of the main entropy generation sources in the tandem stators. In addition, the spanwise LS distribution remarkably affects the load distribution of the stator in spanwise direction by altering the body force. Specifically, in the tandem stators with lower LS, the overall load near the hub is smaller, but in the range of the midspan and near the casing, the overall load on both the rotor and stator is increased. The former increases overall efficiency, while the latter triggers an earlier stall near the rotor tip.
{"title":"Load split design strategy of tandem stators in a highly loaded micro axial compressor","authors":"Xiaochen Mao , Fu Lei , Yunyu Wang , Zhihua Ding , Hao Cheng , Bo Liu","doi":"10.1016/j.ast.2025.110040","DOIUrl":"10.1016/j.ast.2025.110040","url":null,"abstract":"<div><div>To investigate the load split (LS) effects on the performance and flow mechanisms of a cantilevered tandem stator in a highly loaded micro axial compressor, three typical tandem blade schemes were thoroughly studied from multiple perspectives using steady-state numerical simulations. The results show that in the <em>LS</em> design of the tandem blades, the trade-off effects between highly and lowly loaded conditions are essential to achieve superior overall performance. The gap jet serves a pivotal function in leakage flow behaviors, acting as a vital link between the leakage flow from the front blade (FB) and rear blade (RB). Furthermore, the mixing effects between the front blade wake and gap jet is one of the main entropy generation sources in the tandem stators. In addition, the spanwise <em>LS</em> distribution remarkably affects the load distribution of the stator in spanwise direction by altering the body force. Specifically, in the tandem stators with lower <em>LS</em>, the overall load near the hub is smaller, but in the range of the midspan and near the casing, the overall load on both the rotor and stator is increased. The former increases overall efficiency, while the latter triggers an earlier stall near the rotor tip.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"160 ","pages":"Article 110040"},"PeriodicalIF":5.0,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387893","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 : 2025-02-07DOI: 10.1016/j.ast.2025.110027
Peimin Xie , Yuanhua Liu , Wei Yuan
The intake plays an important role in the supersonic propulsion system, which restricts the performance of the entire propulsion system. It has been a challenge to ensure that the intake performs well in wide operating range. In this study, based on the multi-objective genetic algorithm, the baseline geometry of the intake is firstly optimized with Ma4 as the design point, and the total pressure coefficient at the outlet of the intake is 0.574. Secondly, in response to the performance decline and starting issues of the intake at off-design points, research is conducted on the scheme and physical mechanisms involving bleed flow control and the axial relative movement of the center body. The axial relative displacement of the center body decreases by 8.98 % due to the introduction of bleed slots, enabling the intake to start under conditions of larger internal contraction ratio. The mass flow rate loss caused by the bleed slots can be compensated by moving the center body and increasing the internal contraction ratio, as it enlarges the capture area of the intake. At Ma0=4, the intake achieves a 2.58% increase in total pressure recovery with a 1.284 % bleed flow rate for the separation bubble eliminated. At Ma0=1.5, the intake achieves a 6.47 % increase in total pressure recovery with a 6.6 % bleed flow rate, because the internal contraction ratio of the intake is enlarged and the terminal shock wave/boundary layer interaction is suppressed. But excessive bleed flow rate leads to the enhancement of terminal shock wave train which is detrimental.
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