Research on Influence of Aerodynamic Force on the Aerodynamic Heat for the Hypersonic Vehicle

2012 ◽  
Vol 198-199 ◽  
pp. 207-211
Author(s):  
Yu Xiang Zhang ◽  
Jin Biao Xu ◽  
Fu Hou Xu ◽  
Hua Cheng Li
Keyword(s):  
Heat Flux ◽  
Friction Force ◽  
Aerodynamic Force ◽  
Angle Of Attack ◽  
Hypersonic Vehicle ◽  
Aerodynamic Heating ◽  
Thermal Change ◽  
Flux Change ◽  
Good Consistency ◽  
The Relationship

During the flight of the hypersonic Vehicle, the angle of attack will change with the flight attitude. At the same time, the aerodynamic forces from the surface of aircraft will also be changing. The pressure and friction force are the main causes of the aerodynamic heating, so the surface aerodynamic heating will change. By used the method of numerical calculation, the passage studied the influence the change the pressure and friction force on the distribution of heat flux in different angle of attack and the relationship between the change of the force of lift-drag and aerodynamic heating. The research suggested that the distribution of the heat flux had very good consistency with that of pressure and friction. The lift change was the dominant factors influence of pneumatic thermal change; the change of drag force affected only the speed of heat flux change.

Thermal and structural response of aerospike mounted on blunt-nose body

2020 ◽  
pp. 095441002097648
Author(s):  
Zhang ZhunHyok ◽  
Won CholJin ◽  
Ri CholUk ◽  
Kim CholJin ◽  
Kim RyongSop
Keyword(s):  
Aerodynamic Force ◽  
Coupling Effect ◽  
Angle Of Attack ◽  
Structural Response ◽  
Response Characteristic ◽  
Wave Drag ◽  
Hypersonic Vehicle ◽  
Loosely Coupled ◽  
Calculation Results ◽  
Blunt Nose

The inclusion of aerospike on blunt nose body of hypersonic vehicle has been considered to be the simplest and most efficient technique for a concurrent reduction of both aeroheating and wave drag due to hypersonic speed. However, the thermal and mechanical behavior of aerospike structure under the coupling effect of aerodynamic force and aeroheating remains unclear. In this study, the thermal and structural response of aerospike mounted on the blunt nose body of hypersonic vehicle was numerically simulated by applying 3 D fluid-thermal-structural coupling method based on loosely-coupled strategy. In the simulation, the angle-of-attack and the spike’s length and diameter are differently set as α = 0°–10°, L/D = 1–2 and d/D = 0.05–0.15, respectively. Through the parametric study, the following results were obtained. Firstly, the increase of vehicle’s angle-of-attack and spike’s length unfavorably affect the thermal and structural response of aerospike. Secondly, the increase of spike’s diameter can improve its structural response characteristic. Finally, the aerospike with the angle-of-attack of 0° and the length and diameter of L/D = 1 and d/D = 0.15, respectively, is preferred in consideration of the effect of flight angle-of-attack and spike’s geometrical structure on the thermal and structural response of spike and the drag reduction of vehicle. The numerical calculation results provide a technical support for the safe design of aerospike.

scholarly journals Disturbed motion of a hypersonic vehicle in climb

2019 ◽  
Vol 18 (2) ◽  
pp. 7-20 ◽  
Author(s):  
V. L. Balakin ◽  
M. M. Krikunov
Keyword(s):  
Optimal Control ◽  
Aerodynamic Force ◽  
Angle Of Attack ◽  
Hypersonic Vehicle ◽  
Atmospheric Density ◽  
Optimal Angle ◽  
Control Programs ◽  
Target Values ◽  
Standard Values ◽  
Disturbed Motion

Disturbed motion of a hypersonic vehicle in climb is analyzed. Deviations of atmospheric density from standard values and deviations of aerodynamic force coefficients from nominal values are taken as disturbances. Disturbed motion of a hypersonic vehicle with the optimum angle-of-attack schedule and nominal flight characteristics is modeled. Deviations of terminal conditions of disturbed motion from the target values of velocity, altitude and path inclination are determined. Using the method of Pontryagin’s maximum principle the problem of fuel mass minimum consumed in hypersonic acceleration climb is solved for disturbed motion. Optimal angle-of-attack schedules, optimal flight paths and finite values of the hypersonic vehicle’s mass are determined. Comparative analysis of optimal control programs and flight paths obtained for disturbed and undisturbed motion is carried out.

INVESTIGATING THE RELATIONSHIP BETWEEN SURFACE WICKABILITY AND CRITICAL HEAT FLUX DURING POOL BOILING

2018 ◽  
Author(s):  
Youngsup Song ◽  
Yangying Zhu ◽  
Daniel J. Preston ◽  
H. Jeremy Cho ◽  
Zhengmao Lu ◽  
...  
Keyword(s):  
Heat Flux ◽  
Critical Heat Flux ◽  
Pool Boiling ◽  
The Relationship

Transient Temperature and Heat Flux Measurement in Ultrasonic Joining of Battery Tabs Using Thin-Film Microsensors

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
Hang Li ◽  
Hongseok Choi ◽  
Chao Ma ◽  
Jingzhou Zhao ◽  
Hongrui Jiang ◽  
...  
Keyword(s):  
Thin Film ◽  
Heat Flux ◽  
Heat Generation ◽  
Welding Process ◽  
Ultrasonic Welding ◽  
Transient Temperature ◽  
Monitoring And Control ◽  
Change Rate ◽  
Flux Change ◽  
And Control

Process physics understanding, real time monitoring, and control of various manufacturing processes, such as battery manufacturing, are crucial for product quality assurance. While ultrasonic welding has been used for joining batteries in electric vehicles (EVs), the welding physics, and process attributes, such as the heat generation and heat flow during the joining process, is still not well understood leading to time-consuming trial-and-error based process optimization. This study is to investigate thermal phenomena (i.e., transient temperature and heat flux) by using micro thin-film thermocouples (TFTC) and thin-film thermopile (TFTP) arrays (referred to as microsensors in this paper) at the very vicinity of the ultrasonic welding spot during joining of three-layered battery tabs and Cu buss bars (i.e., battery interconnect) as in General Motors's (GM) Chevy Volt. Microsensors were first fabricated on the buss bars. A series of experiments were then conducted to investigate the dynamic heat generation during the welding process. Experimental results showed that TFTCs enabled the sensing of transient temperatures with much higher spatial and temporal resolutions than conventional thermocouples. It was further found that the TFTPs were more sensitive to the transient heat generation process during welding than TFTCs. More significantly, the heat flux change rate was found to be able to provide better insight for the process. It provided evidence indicating that the ultrasonic welding process involves three distinct stages, i.e., friction heating, plastic work, and diffusion bonding stages. The heat flux change rate thus has significant potential to identify the in-situ welding quality, in the context of welding process monitoring, and control of ultrasonic welding process. The weld samples were examined using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) to study the material interactions at the bonding interface as a function of weld time and have successfully validated the proposed three-stage welding theory.

scholarly journals Numerical simulation of flapping airfoil with alula

2020 ◽  
Vol 12 ◽  
pp. 175682932097798
Author(s):  
Han Bao ◽  
Wenqing Yang ◽  
Dongfu Ma ◽  
Wenping Song ◽  
Bifeng Song
Keyword(s):  
Aerodynamic Force ◽  
Angle Of Attack ◽  
Leading Edge ◽  
Aerodynamic Performance ◽  
Geometric Parameters ◽  
Flight Performance ◽  
Relative Angle ◽  
Vertical Distance ◽  
Unsteady Effect ◽  
Flapping Airfoil

Bionic micro aerial vehicles have become popular because of their high thrust efficiency and deceptive appearances. Leading edge or trailing edge devices (such as slots or flaps) are often used to improve the flight performance. Birds in nature also have leading-edge devices, known as the alula that can improve their flight performance at large angles of attack. In the present study, the aerodynamic performance of a flapping airfoil with alula is numerically simulated to illustrate the effects of different alula geometric parameters. Different alula relative angles of attack β (the angle between the chord line of the alula and that of the main airfoil) and vertical distances h between the alula and the main airfoil are simulated at pre-stall and post-stall conditions. Results show that at pre-stall condition, the lift increases with the relative angle of attack and the vertical distance, but the aerodynamic performance is degraded in the presence of alula compared with no alula, whereas at post-stall condition, the alula greatly enhances the lift. However, there seems to be an optimal relative angle of attack for the maximum lift enhancement at a fixed vertical distance considering the unsteady effect, which may indicate birds can adjust the alula twisting at different spanwise positions to achieve the best flight performance. Different alula geometric parameters may affect the aerodynamic force by modifying the pressure distribution along the airfoil. The results are instructive for design of flapping-wing bionic unmanned air vehicles.

AC Measurements of a Coupling Between Dissipative Heat Flux and Mutual Friction Force in He II

1974 ◽  
pp. 324-327
Author(s):  
Félix Vidal ◽  
Michel Le Ray ◽  
Maurice François ◽  
Daniel Lhuillier
Keyword(s):  
Heat Flux ◽  
Friction Force ◽  
Mutual Friction ◽  
Dissipative Heat

Nonlinear DOB-based explicit NMPC for station-keeping of a multi-vectored propeller airship with thrust saturation

2018 ◽  
Vol 122 (1257) ◽  
pp. 1753-1774 ◽  
Author(s):  
Y. Wen ◽  
L. Chen ◽  
Y. Wang ◽  
D. Sun ◽  
D. Duan ◽  
...  
Keyword(s):  
Control Method ◽  
Aerodynamic Force ◽  
Wind Effect ◽  
Station Keeping ◽  
Globally Asymptotically Stable ◽  
Tracking Differentiator ◽  
Propulsion Force ◽  
Predictive Controller ◽  
Dynamics Models ◽  
The Relationship

ABSTRACTA nonlinear station-keeping control method for a multi-vectored propeller airship under unknown wind field with thrust saturation is developed, which is composed of three modules: nonlinear model predictive controller (NMPC), disturbance observer (DOB) and tracking differentiator (TD). The nonlinear kinematics and dynamics models are introduced, and the wind effect is considered by the wind-induced aerodynamic force. Based on both models, an explicit NMPC is designed. Then a nonlinear DOB is introduced to estimate the wind disturbance. A TD, showing the relationship between the maximum propulsion force and the maximum flight acceleration, is proposed to handle the thrusts’ amplitude saturation. Stability analysis shows that the closed-loop system is globally asymptotically stable. Simulations for a multi-vectored propeller airship are conducted to demonstrate the robustness and effectiveness of the proposed method.

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