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In this paper, the output performance of an aerospace pyrotechnic device by simulation is studied. First, the change curve of pressure vs. time of single igniter and double ignition is respectively simulated by SIMULINK simulation software. The result shows that the maximum pressure of the single igniter is 16MPa when the time reaches to 2.5ms. While, with the double ignition, the maximum pressure...
The model of Realizable ?-e in fluent of computational fluid dynamics software was used to numerically simulate unsteady turbulent flow in spiral tube. In order to get the sound pressure with time variation diagram and the sound field spectrogram, the situation of flow field was analyzed and the acoustic field was monitored by the FW-H equation. The results show that the pressure of fluid to the internal...
In wind farms, the performance of downstream wind turbines is significantly affected by the upstream turbine wakes. In this study, we focus on the wake interactions of two horizontal-axis wind turbines, and the separation distance has been investigated using a Reynolds-averaged Navier-Stokes (RANS) framework. Three models for two in-line turbines arranged with different separation distances have been...
Wind shear inflow conditions with different indices lead to different wind speed distributions in wind turbine wakes, which further affects the power output of downstream turbines. In this study we focus on wind turbine wake considering different inflow shear indices. The three-dimensional numerical simulation, based on the full NREL 5-MW wind turbine model, was implemented with the RNG k-epsilon...
Wind turbine wakes and their interactions with atmospheric boundary layer (ABL) flows have a significant impact on the performance of wind turbines and wind farms, and thus it is essential to understand the flow dynamics imposed by ABL flows and wind turbine wakes. In this study, we focus on the impact of ambient turbulence on wind turbine wakes in the neutral ABL. Full rotor models, including the...
Gurney flap and trailing-edge wedge are useful devices to improve the aerodynamic performance of aerofoils for wind turbines; however, the researches on blunt trailing-edge aerofoil are limited. In this paper, we focus on the flow mechanism of Gurney flaps and trailing-edge wedges and their impacts on a blunt trailing-edge aerofoil DU97-W-300. Two-dimensional Computational Fluid Dynamics (CFD) models...
The commercial computer fluid dynamics software package FLUENT was used to simulate the flow field of the new toilet system. The mesh model of the flow field was built with the GAMBIT. With the numerical simulation of the flow field on air intakes and flushing system, the pressure and velocity vector cloud diagram have been given. The information would be very useful in experimental investigation...
The new toilet system which applied to the train was designed. The toilet system can separate the excrement and urine in the source, and deal with them individually. The problem that the direct discharge of excrement and urine polluted the surrounding environment was solved by this way. The flushing system was driven by the negative pressure which generated by the air around the high-speed train....
In order to master the law of mining induced overlying rock fissure and provide a reasonable scientific basis for safety mining under water. Orthogonal experimental design method and FLAC (FLAC, Fast Lagrangian Analysis for Continuum) program were used to obtain effective training samples for SVM (Support Vector Machine). Through reasonable selection of SVM parameters, SVM model was established between...
Based on control equations in fluid dynamics, the main thought of oil spray process for full-automatic cold header is proposed according to the idea of green manufacturing. The CFD software is applied to simulate the multiphase oil mist flow in control box of the oil spray process with numerical method. The simulation results are discussed including temperature, pressure, velocity and multiphase fluid...
The optical bistability of Tm, Ho:YLF laser is theoretically investigated based on the rate equation theory model in this paper. The optical bistability output is obtained by numerical simulation, and the influence of energy transfer upconversion on the bistability behavior is analyzed. Furthermore, the formation scheme of optical bistability is also discussed by the relation between the gain and...
The forging method with horizontal V-shaped anvils (HVA) is effective in the control of inner stress states, metal tissue, etc. FEM numerical simulation is conducted for the HVA forging method, given the blank-width ratio 0.5, 1.0 and 1.2, respectively, and the anvil-width ratio 1.0, to investigate the influence of blank-width ratio of HVAs on the stress field in the stretched forgings. The results...
A synchronization method of adaptive backstepping sliding-mode control is presented based on the multiscroll chaotic systems with hysteresis nonlinear function and unknown parameters. The strategy is designed by a step-by-step procedure interlacing. At each step, a coordinate transformation, the design of a virtual control via a Lyapunov technique and the definition of a tuning function are derived,...
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