Research

Jump to: Review

20 pages, 6883 KiB

Open AccessArticle

Effects of Flow Spillage Strategies on the Aerodynamic Characteristics of Diverterless Hypersonic Inlets

by Zonghan Yu, Huihui Huang, Ruilin Wang, Yuedi Lei, Xueyang Yan, Zikang Jin, Omer Musa and Guoping Huang

Aerospace 2022, 9(12), 771; https://doi.org/10.3390/aerospace9120771 - 29 Nov 2022

Cited by 1 | Viewed by 1953

Abstract

This paper compares the aerodynamic characteristics of a central-spillage diverterless hypersonic inlet (i.e., bump inlet, Form 1) with a side-spillage inlet (Form 2) under on/off design conditions when faced with non-uniform inflow. Both forms are designed for a flight Mach number of 6.0 [...] Read more.

This paper compares the aerodynamic characteristics of a central-spillage diverterless hypersonic inlet (i.e., bump inlet, Form 1) with a side-spillage inlet (Form 2) under on/off design conditions when faced with non-uniform inflow. Both forms are designed for a flight Mach number of 6.0 and a cruise altitude of 24.0 km. Numerical methods are introduced and validated. Integrated design results indicate that based on identical contraction ratios, Form 2 is 27.8% lower in height, 28.3% shorter in length, and 34.4% smaller in the windward projection area than Form 1. This provides the evidence that the side-spillage strategy will suppress the external drag less. Then, the aerodynamic performance is investigated under various upstream/downstream boundary conditions (inflow speed range: Mach 2.0~6.0; backpressure fluctuation range: 1~110.0 times the freestream static pressure). The evaluation methods for non-uniform flow fields are first introduced in this paper. Form 2 has a relatively stronger shock system, which allows it to suppress 4.52% more of the pressure fluctuation from the downstream combustion chamber than Form 1. The inlet start margin is widened by approximately 250% due to the self-adaptive flow spillage ability established by the side-spillage strategy. Furthermore, the compression efficiency, internal shock system, spillage ability, etc., are analyzed in detail. In summary, the side-spillage flow organization strategy has better potential for designing wide-ranging air-breathing flight vehicles. Full article

(This article belongs to the Special Issue Hypersonics: Emerging Research)

► Show Figures

Figure 1

19 pages, 11540 KiB

Open AccessArticle

Aerodisk Effect on Hypersonic Boundary Layer Transition and Heat Transfer of HIFiRE-5 Vehicle

by Yatian Zhao, Zhiyuan Shao and Hongkang Liu

Aerospace 2022, 9(12), 742; https://doi.org/10.3390/aerospace9120742 - 23 Nov 2022

Viewed by 1795

Abstract

The substantial aerodynamic drag and severe aerothermal loads, which are closely related to boundary layer transition, challenge the design of hypersonic vehicles and could be relieved by active methods aimed at drag and heat flux reduction, such as aerodisk. However, the research of [...] Read more.

The substantial aerodynamic drag and severe aerothermal loads, which are closely related to boundary layer transition, challenge the design of hypersonic vehicles and could be relieved by active methods aimed at drag and heat flux reduction, such as aerodisk. However, the research of aerodisk effects on transitional flows is still not abundant. Based on the improved k-ω-γ transition model, this study investigates the influence of the aerodisk with various lengths on hypersonic boundary layer transition and surface heat flux distribution over HIFiRE-5 configuration under various angles of attack. Certain meaningful analysis and results are obtained: (i) The existence of aerodisk is found to directly trigger separation-induced transition, moving the transition onset near the centerline upstream and widening the transition region; (ii) The maximum wall heat flux could be effectively reduced by aerodisk up to 52.1% and the maximum surface pressure can even be reduced up to 80.4%. The transition shapes are identical, while the variety of growth rates of intermittency are non-monotonous with the increase in aerodisk length. The dilation of region with high heat flux boundary layer is regarded as an inevitable compromise to reducing maximum heat flux and maximum surface pressure. (iii) With the angle of attack rising, first, the transition is postponed and subsequently advanced on the windward surface, which is in contrast to the continuously extending transition region on the leeward surface. This numerical study aims to explore the effects of aerodisk on hypersonic boundary layer transition, enrich the study of hypersonic flow field characteristics and active thermal protection system considering realistic boundary layer transition, and provide references for the excogitation and utilization of hypersonic vehicle aerodisk. Full article

(This article belongs to the Special Issue Hypersonics: Emerging Research)

► Show Figures

Figure 1

14 pages, 8026 KiB

Open AccessArticle

Assessing the Performance of Hypersonic Inlets by Applying a Heat Source with the Throttling Effect

by Nurfathin Zahrolayali, Mohd Rashdan Saad, Azam Che Idris and Mohd Rosdzimin Abdul Rahman

Aerospace 2022, 9(8), 449; https://doi.org/10.3390/aerospace9080449 - 16 Aug 2022

Viewed by 2426

Abstract

Utilization of a heat source to regulate the shock wave–boundary layer interaction (SWBLI) of hypersonic inlets during throttling was computationally investigated. A plug was installed at the intake isolator’s exit, which caused throttling. The location of the heat source was established by analysing [...] Read more.

Utilization of a heat source to regulate the shock wave–boundary layer interaction (SWBLI) of hypersonic inlets during throttling was computationally investigated. A plug was installed at the intake isolator’s exit, which caused throttling. The location of the heat source was established by analysing the interaction of the shockwave from the compression ramp and the contact spot of the shockwave with that of the inlet cowl. Shockwave interaction inside the isolator was investigated using steady and transient cases. The present computational work was validated using previous experimental work. The flow distortion (FD) and total pressure recovery (TPR) of the inflows were also studied. We found that varying the size and power of the heat source influenced the shockwaves that originated around it and affected the SWBLI within the isolator. This influenced most of the performance measures. As a result, the TPR increased and the FD decreased when the heat source was applied. Thus, the use of a heat source for flow control was found to influence the performance of hypersonic intakes. Full article

(This article belongs to the Special Issue Hypersonics: Emerging Research)

► Show Figures

Figure 1

22 pages, 5567 KiB

Open AccessArticle

A Novel Direct Optimization Framework for Hypersonic Waverider Inverse Design Methods

by Jiwon Son, Chankyu Son and Kwanjung Yee

Aerospace 2022, 9(7), 348; https://doi.org/10.3390/aerospace9070348 - 29 Jun 2022

Cited by 1 | Viewed by 2627

Abstract

Waverider is a hypersonic vehicle that improves the lift-to-drag ratio using the shockwave attached to the leading edge of the lifting surface. Owing to its superior aerodynamic performance, it exhibits a viable external configuration in hypersonic flight conditions. Most of the existing studies [...] Read more.

Waverider is a hypersonic vehicle that improves the lift-to-drag ratio using the shockwave attached to the leading edge of the lifting surface. Owing to its superior aerodynamic performance, it exhibits a viable external configuration in hypersonic flight conditions. Most of the existing studies on waverider employ the inverse design method to generate vehicle configuration. However, the waverider inverse design method exhibits two limitations; inaccurate definition of design space and unfeasible performance estimation during the design process. To address these issues, a novel framework to directly optimize the waverider is proposed in this paper. The osculating cone theory is adopted as a waverider inverse design method. A general methodology to define the design space is suggested by analyzing the design curves of the osculating cone theory. The performance of the waverider is estimated accurately and rapidly via combining a high-fidelity computational fluid dynamics solver and a surrogate model. A comparison study shows that the proposed direct optimization framework enables a more accurate design space and efficient performance estimation. The framework is applied to the multi-objective optimization problem, which maximizes internal volume and minimizes aerodynamic drag. Finally, general characteristics for waverider are presented by analyzing the optimized results with data mining methods such as K-means. Full article

(This article belongs to the Special Issue Hypersonics: Emerging Research)

► Show Figures

Figure 1

14 pages, 20956 KiB

Open AccessArticle

MC-New: A Program to Calculate Newtonian Aerodynamic Coefficients Based on Monte-Carlo Integration

by Michiko Ahn Furudate

Aerospace 2022, 9(6), 330; https://doi.org/10.3390/aerospace9060330 - 20 Jun 2022

Viewed by 2799

Abstract

A computer program, MC-New, to calculate Newtonian aerodynamics is presented. The aerodynamic coefficients of a geometry expressed by an analytic function are calculated in a Monte-Carlo integration manner, in which the local forces on the randomly chosen sample points are summed up. The [...] Read more.

A computer program, MC-New, to calculate Newtonian aerodynamics is presented. The aerodynamic coefficients of a geometry expressed by an analytic function are calculated in a Monte-Carlo integration manner, in which the local forces on the randomly chosen sample points are summed up. The verification study and the accuracy analysis show that the program can provide good approximations of exact solutions. The example results of the parametric study on the Apollo-like entry capsule geometry are presented, showing the potential capability of the MC-New program as an efficient open-source tool for designing hypersonic vehicles. Full article

(This article belongs to the Special Issue Hypersonics: Emerging Research)

► Show Figures

Figure 1

19 pages, 5078 KiB

Open AccessArticle

Assessment of Radiative Heating for Hypersonic Earth Reentry Using Nongray Step Models

by Xinglian Yang, Jingying Wang, Yue Zhou and Ke Sun

Aerospace 2022, 9(4), 219; https://doi.org/10.3390/aerospace9040219 - 15 Apr 2022

Cited by 2 | Viewed by 2578

Abstract

Accurate prediction of the aerothermal environment is of great significance to space exploration and return missions. The canonical Fire II trajectory points are simulated to investigate the radiative transfer in the shock layer for Earth reentry at hypervelocity above 10 km/s using a [...] Read more.

Accurate prediction of the aerothermal environment is of great significance to space exploration and return missions. The canonical Fire II trajectory points are simulated to investigate the radiative transfer in the shock layer for Earth reentry at hypervelocity above 10 km/s using a developed radiation–flowfield uncoupling method. The thermochemical nonequilibrium flow is solved by an in-house PHAROS Navier–Stokes code, while the nongray radiation is integrated by the tangent slab approximation, respectively, combined with the two-, five-, and eight-step models. For the convective heating, the present results agree well with the data of Anderson’s relation. For the radiative heating, the two-step model predicts the closest values with the results of Tauber and Sutton’s relationship, while the five- and eight-step models predict far greater. The three-step models all present the same order of magnitude of radiative heating of 1 MW/m² and show a consistent tendency with the engineering estimation. The Planck-mean absorption coefficient is calculated to show the radiative transfer significantly occurs in the shock layer. By performing the steady simulation at each flight trajectory point, the present algorithm using a nongray step model with moderate efficiency and reasonable accuracy is promising to solve the real-time problem in engineering for predicting both convective and radiative heating to the atmospheric reentry vehicle in the future. Full article

(This article belongs to the Special Issue Hypersonics: Emerging Research)

► Show Figures

Figure 1

15 pages, 3121 KiB

Open AccessArticle

Angular-Accelerometer-Based Flexible-State Estimation and Tracking Controller Design for Hypersonic Flight Vehicle

by Daqiao Zhang, Xiaolong Zheng, Yangguang Xie and Xiaoxiang Hu

Aerospace 2022, 9(4), 206; https://doi.org/10.3390/aerospace9040206 - 10 Apr 2022

Cited by 5 | Viewed by 1936

Abstract

The controller design of hypersonic flight vehicles is a challenging task, especially when its flexible states are immeasurable. Unfortunately, the flexible states are difficult to measure directly. In this paper, an angular-accelerometer-based method for the estimation of flexible states is proposed. By adding [...] Read more.

The controller design of hypersonic flight vehicles is a challenging task, especially when its flexible states are immeasurable. Unfortunately, the flexible states are difficult to measure directly. In this paper, an angular-accelerometer-based method for the estimation of flexible states is proposed. By adding a pitch angel angular accelerometer and designing an Extended Kalman Filter-based online estimation method, the flexible states could be obtained in real time. Then, based on the estimated flexible states, a stable inversion-based controller-design method was utilized, and a robust tracking controller was designed for hypersonic flight vehicles. The proposed method provides an effective means of estimating flexible states and conducting the observer-based controller design of hypersonic flight vehicles. Finally, a numeral simulation is given to show the effectiveness of the proposed control method. Full article

(This article belongs to the Special Issue Hypersonics: Emerging Research)

► Show Figures

Figure 1

17 pages, 3660 KiB

Open AccessArticle

A Real-Time Trajectory Optimization Method for Hypersonic Vehicles Based on a Deep Neural Network

by Jianying Wang, Yuanpei Wu, Ming Liu, Ming Yang and Haizhao Liang

Aerospace 2022, 9(4), 188; https://doi.org/10.3390/aerospace9040188 - 01 Apr 2022

Cited by 14 | Viewed by 3607

Abstract

Considering the high-efficient trajectory planning requirements for hypersonic vehicles, this paper proposes a real-time trajectory optimization method based on a deep neural network. First, the trajectory optimization model of the hypersonic vehicle reentry phase is developed. The pseudo-spectral method is used to perform [...] Read more.

Considering the high-efficient trajectory planning requirements for hypersonic vehicles, this paper proposes a real-time trajectory optimization method based on a deep neural network. First, the trajectory optimization model of the hypersonic vehicle reentry phase is developed. The pseudo-spectral method is used to perform the trajectory optimization offline, and multiple optimal trajectory data are obtained. In addition, based on the inherent relationship between the state and control variables of a trajectory, a neural network is established to predict the current control outputs. The sample library of optimal trajectory data is used to train the parameters of the deep neural network to obtain an optimal neural network model. Finally, the simulation verification of the hypersonic vehicle reentry phase is performed. The simulation results show that under the condition of the initial value deviation and environmental interference, the proposed deep learning-based method can achieve a fast generation of hypersonic vehicle optimal trajectories, while achieving the advantages of high computational efficiency and reliability. Compared to traditional trajectory optimization algorithms, the proposed method has the generalization capability that satisfies the accuracy requirements and meets the demands of online real-time trajectory optimization. Full article

(This article belongs to the Special Issue Hypersonics: Emerging Research)

► Show Figures

Figure 1

17 pages, 2124 KiB

Open AccessArticle

Optimal Guidance Laws for a Hypersonic Multiplayer Pursuit-Evasion Game Based on a Differential Game Strategy

by Haizhao Liang, Zhi Li, Jinze Wu, Yu Zheng, Hongyu Chu and Jianying Wang

Aerospace 2022, 9(2), 97; https://doi.org/10.3390/aerospace9020097 - 12 Feb 2022

Cited by 9 | Viewed by 2646

Abstract

The guidance problem of a confrontation between an interceptor, a hypersonic vehicle, and an active defender is investigated in this paper. As a hypersonic multiplayer pursuit-evasion game, the optimal guidance scheme for each adversary in the engagement is proposed on the basis of [...] Read more.

The guidance problem of a confrontation between an interceptor, a hypersonic vehicle, and an active defender is investigated in this paper. As a hypersonic multiplayer pursuit-evasion game, the optimal guidance scheme for each adversary in the engagement is proposed on the basis of linear-quadratic differential game strategy. In this setting, the angle of attack is designed as the output of guidance laws, in order to match up with the nonlinear dynamics of adversaries. Analytical expressions of the guidance laws are obtained by solving the Riccati differential equation derived by the closed-loop system. Furthermore, the satisfaction of the saddle-point condition of the proposed guidance laws is proven mathematically according to the minimax principle. Finally, nonlinear numerical examples based on 3-DOF dynamics of hypersonic vehicles are presented, to validate the analytical analysis in this study. By comparing different guidance schemes, the effectiveness of the proposed guidance strategies is demonstrated. Players in the engagement could improve their performance in confrontation by employing the proposed optimal guidance approaches with appropriate weight parameters. Full article

(This article belongs to the Special Issue Hypersonics: Emerging Research)

► Show Figures

Figure 1

12 pages, 6138 KiB

Open AccessArticle

Mach 4 Simulating Experiment of Pre-Cooled Turbojet Engine Using Liquid Hydrogen

by Hideyuki Taguchi, Kenya Harada, Hiroaki Kobayashi, Motoyuki Hongoh, Daisaku Masaki and Shunsuke Nishida

Aerospace 2022, 9(1), 39; https://doi.org/10.3390/aerospace9010039 - 14 Jan 2022

Cited by 4 | Viewed by 2665

Abstract

This study investigated a pre-cooled turbojet engine for a Mach 5 class hypersonic transport aircraft. The engine was demonstrated under takeoff and Mach 2 flight conditions, and a Mach 5 propulsion wind tunnel test is planned. The engine is composed of a pre-cooler, [...] Read more.

This study investigated a pre-cooled turbojet engine for a Mach 5 class hypersonic transport aircraft. The engine was demonstrated under takeoff and Mach 2 flight conditions, and a Mach 5 propulsion wind tunnel test is planned. The engine is composed of a pre-cooler, a core engine, and an afterburner. The engine was tested under simulated Mach 4 conditions using an air supply facility. High-temperature air under high pressure was supplied to the engine components through an airflow control valve and an orifice flow meter, and liquid hydrogen was supplied to the pre-cooler and the core engine. The results confirmed that the starting sequence of the engine components was effective under simulated Mach 4 conditions using liquid hydrogen fuel. The pre-cooling effect caused no damage to the rotating parts of the core engine in the experiment. Full article

(This article belongs to the Special Issue Hypersonics: Emerging Research)

► Show Figures

Figure 1

15 pages, 7371 KiB

Open AccessArticle

Coupled Fluid-Thermal Investigation on Drag and Heat Reduction of a Hypersonic Spiked Blunt Body with an Aerodisk

by Bing Fan and Jie Huang

Aerospace 2022, 9(1), 19; https://doi.org/10.3390/aerospace9010019 - 30 Dec 2021

Cited by 4 | Viewed by 1857

Abstract

In the traditional investigations on the drag and heat reduction of hypersonic spiked models, only the aerodynamic calculation is performed, and the structural temperature cannot be obtained. This paper adopted the loosely coupled method to study its efficiency of drag and heat reduction, [...] Read more.

In the traditional investigations on the drag and heat reduction of hypersonic spiked models, only the aerodynamic calculation is performed, and the structural temperature cannot be obtained. This paper adopted the loosely coupled method to study its efficiency of drag and heat reduction, in which the feedback effect of wall temperature rise on aeroheating is considered. The aeroheating and structural temperature were obtained by the CFD and ABAQUS software respectively. The coupling analysis of the hypersonic circular tube was carried out to verify the accuracy of the fluid field, the structural temperature, and the coupled method. Compared with experimental results, the calculated results showed that the relative errors of stagnation heat flux and stagnation temperature were 1.34% and 4.95% respectively, and thus the effectiveness of the coupled method was verified. Installing a spike reduced the total drag of the forebody. The spiked model with an aerodisk reduced the aeroheating of the forebody, while the model without an aerodisk intensified the aeroheating. The spiked model with a planar aerodisk had the best performance on drag and heat reduction among all the models. In addition, increasing the length of the spike reduced the drag and temperature of the forebody. With the increase of the length, the change rates of drag, pressure, heat flux, and temperature decreased gradually. Increasing the diameter of the aerodisk also reduced the temperature of the forebody, while the efficiency of forebody drag reduction first increased and then decreased. In conclusion, the heat and drag reduction must be considered comprehensively for the optimal design of the spike. Full article

(This article belongs to the Special Issue Hypersonics: Emerging Research)

► Show Figures

Figure 1

22 pages, 647 KiB

Open AccessArticle

Review of Reduced-Order Models for Homogeneous CO₂ Nucleation in Supersonic and Hypersonic Expansion Flows

by Philip A. Lax and Sergey B. Leonov

Aerospace 2021, 8(12), 368; https://doi.org/10.3390/aerospace8120368 - 27 Nov 2021

Cited by 3 | Viewed by 2686

Abstract

Several classical and non-classical reduced-order nucleation rate models are presented and compared to experimental values for the homogeneous nucleation rate of

{CO}_{2}

in supersonic nozzles. The most accurate models are identified and are used in simulations of a condensing supersonic expansion flow. [...] Read more.

Several classical and non-classical reduced-order nucleation rate models are presented and compared to experimental values for the homogeneous nucleation rate of

{CO}_{2}

in supersonic nozzles. The most accurate models are identified and are used in simulations of a condensing supersonic expansion flow. Experimental results for the condensation onset point of

{CO}_{2}

in a variety of expansion facilities are presented and compared to simulations and to new data acquired at the SBR-50 facility at the University of Notre Dame. Full article

(This article belongs to the Special Issue Hypersonics: Emerging Research)

► Show Figures

Figure 1

18 pages, 8488 KiB

Open AccessArticle

Spillage-Adaptive Fixed-Geometry Bump Inlet of Wide Speed Range

by Zonghan Yu, Guoping Huang, Ruilin Wang and Omer Musa

Aerospace 2021, 8(11), 340; https://doi.org/10.3390/aerospace8110340 - 11 Nov 2021

Cited by 5 | Viewed by 2582

Abstract

In this work, a new spillage-adaptive bump inlet concept is proposed to widen the speed range for hypersonic air-breathing flight vehicles. Various approaches to improve the inlet start-ability are summarized and compared, among which the bump-inlet pattern holds the merits of high lift-to-drag [...] Read more.

In this work, a new spillage-adaptive bump inlet concept is proposed to widen the speed range for hypersonic air-breathing flight vehicles. Various approaches to improve the inlet start-ability are summarized and compared, among which the bump-inlet pattern holds the merits of high lift-to-drag ratio, boundary layer diversion, and flexible integration ability. The proposed spillage-adaptive concept ensures the inlet starting performance by spilling extra mass flow away at low speed number conditions. The inlet presetting position is determined by synthetically evaluating the flow uniformity and the low-kinetic-energy fluid proportion. The numerical results show that the flow spillage of the inlet increases with the inflow speed decrease, which makes the inlet easier to start at low speed conditions (M 2.5–6.0). The effects of the boundary layer on spillage are also studied in this work. The new integration pattern releases the flow spillage potentials of three-dimensional inward-turning inlets by reasonably arranging the inlet compression on the bump surface. Future work will focus on the spillage-controllable design method. Full article

(This article belongs to the Special Issue Hypersonics: Emerging Research)

► Show Figures

Figure 1

21 pages, 7828 KiB

Open AccessArticle

Redistribution of Energy during Interaction of a Shock Wave with a Temperature Layered Plasma Region at Hypersonic Speeds

by O. A. Azarova, T. A. Lapushkina, K. V. Krasnobaev and O. V. Kravchenko

Aerospace 2021, 8(11), 326; https://doi.org/10.3390/aerospace8110326 - 01 Nov 2021

Cited by 7 | Viewed by 1939

Abstract

The paper is devoted to the problem of the interaction between a shock wave and a thermally stratified energy source for the purpose of supersonic/hypersonic flow control realization. The effect of the thermally stratified energy source on a shock wave with the Mach [...] Read more.

The paper is devoted to the problem of the interaction between a shock wave and a thermally stratified energy source for the purpose of supersonic/hypersonic flow control realization. The effect of the thermally stratified energy source on a shock wave with the Mach number in the range of 6–12 is researched numerically based on the Navier-Stokes system of equations. Redistribution of specific internal energy and volume density of kinetic energy behind the wave front is investigated. Multiple manifestations of the Richtmyer-Meshkov instability has been obtained which has caused the blurring and disappearance of shock wave and contact discontinuity fronts in density fields. A study of the efficiency of using a stratified energy source instead of a homogeneous one with the same value of the full energy is carried out. The agreement with the available experimental data for the shock wave Mach number 6 has been obtained. Full article

(This article belongs to the Special Issue Hypersonics: Emerging Research)

► Show Figures

Figure 1

10 pages, 3513 KiB

Open AccessArticle

Aerodynamic Characteristics of Re-Entry Capsules with Hyperbolic Contours

by Hirotaka Otsu

Aerospace 2021, 8(10), 287; https://doi.org/10.3390/aerospace8100287 - 03 Oct 2021

Cited by 8 | Viewed by 3366

Abstract

For most re-entry capsules, the shape of the forebody of the capsule is designed based on the blunted nose cone. A similar shape can be created using a hyperboloid of revolution that can control the nose bluntness and the half angle of the [...] Read more.

For most re-entry capsules, the shape of the forebody of the capsule is designed based on the blunted nose cone. A similar shape can be created using a hyperboloid of revolution that can control the nose bluntness and the half angle of the cone easily. In this study, the hypersonic aerodynamic characteristics of re-entry capsules designed with hyperbolic contours were investigated using the CFD code, FaSTAR, developed by Japan Aerospace Exploration Agency (JAXA). The CFD results showed that, using the hyperbolic contours, the drag and lift coefficients can be increased compared to those for the Hayabusa re-entry capsule without changing the shape of the capsule drastically. This suggests that shape design based on the hyperbolic contours can improve the aerodynamic characteristics of re-entry capsules. Full article

(This article belongs to the Special Issue Hypersonics: Emerging Research)

► Show Figures

Figure 1

13 pages, 4629 KiB

Open AccessArticle

The Rapid Data-Driven Prediction Method of Coupled Fluid–Thermal–Structure for Hypersonic Vehicles

by Jing Liu, Meng Wang and Shu Li

Aerospace 2021, 8(9), 265; https://doi.org/10.3390/aerospace8090265 - 16 Sep 2021

Cited by 2 | Viewed by 2164

Abstract

This work demonstrates the use of Latin Hypercube Sampling and Proper Orthogonal Decomposition in combination with a Radial Basis Function model to perform on vehicle prediction coupled fluid–thermal–structure. We regarded the Mach number, flight altitude and angle of attack as input parameters and [...] Read more.

This work demonstrates the use of Latin Hypercube Sampling and Proper Orthogonal Decomposition in combination with a Radial Basis Function model to perform on vehicle prediction coupled fluid–thermal–structure. We regarded the Mach number, flight altitude and angle of attack as input parameters and established a rapid prediction model. The basic process of numerical simulation of the hypersonic vehicle coupled fluid–thermal–structure was studied to obtain the database of pressure coefficient, heat flux, structural temperature and structural stress as the sample data to train this prediction method. The prediction error was analyzed. The prediction results showed that the data-driven method proposed in this paper based on proper orthogonal decomposition and radial basis function could be used for predicting vehicle coupled fluid–thermal–structure with good efficiency. Full article

(This article belongs to the Special Issue Hypersonics: Emerging Research)

► Show Figures

Figure 1

14 pages, 6583 KiB

Open AccessArticle

Numerical Study on Low-Temperature Region as Heat Sink and Its Heat Dissipation Capacity for Hypersonic Vehicle

by Xinying Jiang, Meng Liu, Hao Wu, Yonggui Zheng and Junjun Zhuang

Aerospace 2021, 8(9), 238; https://doi.org/10.3390/aerospace8090238 - 30 Aug 2021

Cited by 2 | Viewed by 2522

Abstract

Researches have focused on the thermal protection system (TPS) of hypersonic vehicles under severe aerodynamic heat. According to the second law of thermodynamics, heat transfer needs to consume a heat sink, but the cold energy provided by the airborne heat sink is limited. [...] Read more.

Researches have focused on the thermal protection system (TPS) of hypersonic vehicles under severe aerodynamic heat. According to the second law of thermodynamics, heat transfer needs to consume a heat sink, but the cold energy provided by the airborne heat sink is limited. Therefore, it is necessary to explore new available heat sinks during hypersonic cruise. This paper numerically calculated the wall temperature distribution of hypersonic vehicle X-51A with different Mach numbers, altitudes and angles of attack using ANSYS Fluent 19.0. A dimensionless parameter, relative temperature coefficient r_t, was proposed to characterize the relative value of local wall temperature in the whole wall temperature range. The distribution regularity and influencing factors of wall temperature were summarized. The low-temperature region which is less affected by flight conditions was divided as the heat sink and its heat dissipation capacity (Q) and characteristics were studied. The angle of attack has great influence on the temperature distribution. In XY view the rear side of leeward surface is least affected by flight conditions and its r_t is less than 0.2, which can be used as a low-temperature region. Taking this region as a heat sink to dissipate heat, it is found that the Q of the new heat sink is 30 kW/m² at Ma 3, 90 kW/m² at Ma 4 and 200 kW/m² at Ma 5. The Q increases greatly with the increase in Mach number, and the convective heat transfer coefficient (h) also increases. At the same Q, the h decreases with the increase in Mach number. The exploration of low-temperature region as heat sink has an important reference for reducing the dependence on consumable heat sink and alleviating the energy shortage of the hypersonic vehicle. Full article

(This article belongs to the Special Issue Hypersonics: Emerging Research)

► Show Figures

Figure 1

14 pages, 2589 KiB

Open AccessArticle

Global Skewness and Coherence for Hypersonic Shock-Wave/Boundary-Layer Interactions with Pressure-Sensitive Paint

by Carson L. Running and Thomas J. Juliano

Aerospace 2021, 8(5), 123; https://doi.org/10.3390/aerospace8050123 - 22 Apr 2021

Cited by 8 | Viewed by 3143

Abstract

The global surface pressure was measured on a 7

°

half-angle circular cone/flare model at a nominally zero angle of attack using pressure-sensitive paint (PSP). These experiments were conducted to illustrate fast PSP’s usefulness and effectiveness at measuring the unsteady structures inherent to [...] Read more.

The global surface pressure was measured on a 7

°

half-angle circular cone/flare model at a nominally zero angle of attack using pressure-sensitive paint (PSP). These experiments were conducted to illustrate fast PSP’s usefulness and effectiveness at measuring the unsteady structures inherent to hypersonic shock-wave/boundary-layer interactions (SWBLIs). Mean and fluctuating surface pressure was measured with a temperature-corrected, high-frequency-response (≈10 kHz) anodized-aluminum pressure-sensitive paint (AA-PSP) allowing for novel, global calculations of skewness and coherence. These analyses complement traditional SWBLI data-reduction methodologies by providing high-spatial-resolution measurements of the mean and fluctuating locations of the shock feet, as well as the frequency-dependent measure of the relationship between characteristic flow features. The skewness indicated the mean locations of the separation and reattachment shock feet as well as their fluctuations over the course of the test. The coherence indicated that the separation and reattachment shock feet fluctuate about their mean location at the same frequency as one another, but 180 degrees out of phase. This results in a large-scale ‘breathing motion’ of the separated region characteristic of large separation bubbles. These experimental findings validate the usefulness of AA-PSP, and associated data-reduction methodologies, to provide global physical insights of unsteady SWBLI surface behavior in the hypersonic flow regime. Similar methodologies can be incorporated in future experiments to investigate complex and novel SWBLIs. Full article

(This article belongs to the Special Issue Hypersonics: Emerging Research)

► Show Figures

Figure 1

Review

Jump to: Research

12 pages, 982 KiB

Open AccessReview

Assessing the Sustainability of Liquid Hydrogen for Future Hypersonic Aerospace Flight

by Abdalrahman Khaled Mohammad, Charles Sumeray, Maximilian Richmond, Justin Hinshelwood and Aritra Ghosh

Aerospace 2022, 9(12), 801; https://doi.org/10.3390/aerospace9120801 - 06 Dec 2022

Cited by 6 | Viewed by 2433

Abstract

This study explored the applications of liquid hydrogen (LH₂) in aerospace projects, followed by an investigation into the efficiency of ramjets, scramjets, and turbojets for hypersonic flight and the impact of grey, blue, and green hydrogen as an alternative to JP-7 [...] Read more.

This study explored the applications of liquid hydrogen (LH₂) in aerospace projects, followed by an investigation into the efficiency of ramjets, scramjets, and turbojets for hypersonic flight and the impact of grey, blue, and green hydrogen as an alternative to JP-7 and JP-8 (kerosene fuel). The advantage of LH₂ as a propellant in the space sector has emerged from the relatively high energy density of hydrogen per unit volume, enabling it to store more energy compared to conventional fuels. Hydrogen also has the potential to decarbonise space flight as combustion of LH₂ fuel produces zero carbon emissions. However, hydrogen is commonly found in hydrocarbons and water and thus it needs to be extracted from these molecular compounds before use. Only by considering the entire lifecycle of LH₂ including the production phase can its sustainability be understood. The results of this study compared the predicted Life Cycle Assessment (LCA) emissions of the production of LH₂ using grey, blue, and green hydrogen for 2030 with conventional fuel (JP-7 and JP-8) and revealed that the total carbon emissions over the lifecycle of LH₂ were greater than kerosene-derived fuels. Full article

(This article belongs to the Special Issue Hypersonics: Emerging Research)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Hypersonics: Emerging Research

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Published Papers (19 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI