scholarly journals Aerodynamic Characteristics of a Stoker Furnace with Staged Combustion: Comparison of Cold Modeling Experiments and Numerical Simulations

ACS Omega ◽  
2020 ◽  
Vol 5 (27) ◽  
pp. 16332-16341
Author(s):  
Xinwei Guo ◽  
Hao Bai ◽  
Zhongxiao Zhang ◽  
Juan Yu ◽  
Degui Bi ◽  
...  
2018 ◽  
Vol 145 (1) ◽  
pp. 25-46 ◽  
Author(s):  
Robert Głębocki ◽  
Mariusz Jacewicz

The paper deals with a concept of a missile vertical launch system using reaction control jets. The purpose of the study was a detailed investigation of a method optimizing fuel consumption in the first phase of the missile flight to increase the range and optimize the flight path. In the designed system the missile is ejected vertically and turned to the desired position by using corrective engines before the sustainer motor is started. The dynamics and controllability of the missile at low velocities were studied. The physical and mathematical model of the object has been described, taking into account the nonlinearities connected with the dynamics of the rocket itself, the disturbances caused by firing the rocket engine as well as some effects the unsteady aerodynamics. A method identifying the aerodynamic characteristics of the missile and an algorithm controlling the correction engines is presented. A prepared mathematical model of the missile was used to create a simulating environment. The results of numerical simulations in the form of graphs and tables are presented.


2020 ◽  
Vol 10 (4) ◽  
pp. 1272 ◽  
Author(s):  
Yao Lei ◽  
Hengda Wang

In order to study the aerodynamic performance of the quadrotor with different rotor spacings in hover, experiments were performed together with numerical simulations. For experimental study, an experimental platform was designed to measure the thrust and power consumption of the quadrotor with different rotor spacings (L/R = 2.2, 2.6, 3.0, 3.2, 3.6, and 4.0), and to attempt to find out the optimal rotor configuration which makes the quadrotor have the best aerodynamic performance. In addition, the pressure distribution, vorticity of the blade tip, and velocity vector of quadrotor in the flow field were obtained by Computational Fluid Dynamics (CFD) method to visually analyze the aerodynamic interference between adjacent rotors. By the comparison of experimental results and numerical simulations, the final results show that the aerodynamic performance of the quadrotor varies obviously with the change of rotor spacing, and it has a negative impact on hover efficiency if rotor spacing is too much small or large. The rotors pacing at L/R = 3.6 with larger thrust and smaller power is considered to be the best aerodynamic configuration for the quadrotor with better aerodynamic characteristics. Furthermore, compared with the isolated rotor, moderate aerodynamic interference is proved to help improve the aerodynamic performance of the quadrotor with a larger thrust, especially for a rotor spacing at L/R = 3.6.


2017 ◽  
Vol 2017.70 (0) ◽  
pp. 502
Author(s):  
Tomoki UZAKI ◽  
Tomoyuki MUTA ◽  
Nobuyuki TSUBOI ◽  
Yusuke MARU ◽  
Kazuhisa FUJITA

2019 ◽  
Vol 27 (1(133)) ◽  
pp. 78-84
Author(s):  
Paulina Maślanka ◽  
Ryszard Korycki

Defined herein are the two PA-fabrics covering a paraglider wing, with the comparative object being permeable clothing material. The material parameters of textiles are applied in numerical simulations of aerodynamic characteristics using the program ANSYS. The state variable is the pressure within the airfoil profile. The space model of a paraglider wing and plane model of its cross-section in the symmetry plane are analysed. The model was approximated by the coordinates of crucial points and smoothed by the spline-curves. The visualisation of stream filaments shows that it is advisable to cover the wing with the impermeable fabric.


2021 ◽  
Vol 2021 ◽  
pp. 1-23
Author(s):  
Yanqi Zhang ◽  
Zhaoming Zhang

To study the effects of aerodynamic loads on the aerodynamic characteristics of stationary and azimuthally rotating antennas, wind tunnel force tests are conducted using solid and porous plate antennas. The variation of aerodynamic coefficient with azimuth angle is obtained when the antenna is stationary and azimuthal rotation, and the results are compared with those from numerical simulations. The variation in the aerodynamic coefficients with respect to the azimuth angle is found to be sinusoidal for both the solid and porous plate antennas rotating in azimuth. Compared with the antenna stationary, quantitative analysis indicates that the rotational motion increases the maximum value and root mean square of the aerodynamic coefficient. For solid plate antenna, |Cx|_max, |Cmy|_max, and |Cmz|_max increase by 41.6%, 15.0%, and 47.3%, respectively; Cx_rms, Cmy_rms, and Cmz_rms increase by 19.0%, 20.0%, and 19.1%, respectively. For porous plate antenna, |Cx|_max, |Cmy|_max, and |Cmz|_max increase by 30.6%, 71.4%, and 40.9%, respectively; Cx_rms, Cmy_rms, and Cmz_rms increase by 22.9%, 50%, and 20%, respectively. The wind tunnel tests verify the feasibility of using numerical simulations to obtain the flow field results. By analyzing the surface pressure coefficient and vortex core track distribution, the effects of azimuthal rotation on the aerodynamic characteristics of the antenna are further clarified.


2000 ◽  
Vol 45 (9) ◽  
pp. 478-480
Author(s):  
V. M. Fomin ◽  
N. D. Malmus ◽  
A. A. Maslov ◽  
A. P. Shashkin ◽  
T. A. Korotaeva ◽  
...  

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