THE INFLUENCE OF THE PARAMETERS MESHES DURING FORMING CALCULATION DOMAIN ON THE EXAMPLE OF THE PROPELLER

Vestnik UGATU ◽  
2021 ◽  
Vol 25 (2) ◽  
pp. 41-47
Author(s):  
Arsen Vladimirovich Mesropyan ◽  
Yuliya Andreevna Shabelnik
Keyword(s):  
Calculation Domain

Mathematical Modeling of Direct Flame Impingement Heat Transfer

2006 ◽  
Author(s):  
German Malikov ◽  
Vladimir Lisienko ◽  
Yuri Malikov ◽  
John Wagner ◽  
Harry Kurek ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Radiation Transfer ◽  
Convective Diffusion ◽  
Heat Fluxes ◽  
Nox Emissions ◽  
Gas Temperature ◽  
Fine Grid ◽  
Combustion Gas ◽  
Calculation Domain ◽  
Diffusion Transfer

Direct flame impingement (DFI) furnaces consist of large arrays of high velocity combusting jets with temperatures up to 1700 K and impinging on complex configuration surfaces of the work pieces. This results in serious convergence problems DFI modeling and computational efforts. A new method of modeling convective-diffusion transfer (CDT) and zone radiation transfer (RT) employing different calculation schemes with a multi-scale grid is presented. Relatively coarse grid calculation domain allows use of conservative and accurate zone radiation transfer method with only modest computational efforts. A fine grid calculation domain is used to predict convective -diffusion transfer for a representative furnace section, containing a small number of jets that allows to significantly decrease the computer time. The main difficulty of coupling between convective-diffusion transfer (CDT) and radiation heat transfer numerical computations is successfully overcome using a relatively simple algorithm. The method allows one to model the physicochemical process taking place in the DFI and reveals as well as explains many features that are difficult to evaluate from experiments. The results were obtained for high velocities (up to 400 m/s) and high firing rates. Maximum (available for natural gas-air firing) total heat fluxes up to 500 kW/m2 and convective heat fluxes of up to 300 kW/m2 were obtained with relatively 'cold' refractory wall temperatures not exceeding 1300 K. The combustion gas temperature range was 1400-1700 K. A simplified analysis for NOx emissions has been developed as post-processing and shows extremely low NOx emissions (under 15 ppm volume) in DFI systems. Good agreement between measurements and calculations has been obtained. The model developed may be regarded as an efficient tool to compute and optimize industrial furnaces designs in limited time.

Effect of Plenum Chamber Configuration on Airflow Uniformity in Unidirectional Flow Cleanrooms

1994 ◽  
Vol 37 (4) ◽  
pp. 21-27
Author(s):  
Guoping Xie ◽  
Yoshihide Suwa
Keyword(s):  
Numerical Simulation ◽  
Numerical Method ◽  
Pressure Loss ◽  
Simulation Method ◽  
Calculation Domain ◽  
Plenum Chamber ◽  
Unidirectional Flow ◽  
Numerical Simulation Method ◽  
Airflow Distribution ◽  
Simulation Results

Uniformity of airflow distribution in a unidirectional flow cleanroom has been studied experimentally and numerically. The influence of the height of the plenum chamber and the velocity of airflow introduced into the chamber on the airflow uniformity are investigated experimentally. In addition, a numerical simulation method to predict airflow uniformity is proposed, taking into account the characteristics of the pressure loss of the filter. The calculation domain in this study includes not only the cleanroom but also the plenum chamber and the exhaust chamber. The validity of the numerical method is also verified by comparing the simulation results with the experiments. Finally, the numerical method is used to obtain an appropriate height for the plenum chamber.

scholarly journals Synergetic Growth of the Rayleigh–Taylor and Richtmyer–Meshkov Instabilities in the Relativistic Jet

2016 ◽  
Vol 12 (S324) ◽  
pp. 87-88
Author(s):  
Jin Matsumoto ◽  
Youhei Masada
Keyword(s):  
External Medium ◽  
Ambient Medium ◽  
Three Dimensional ◽  
Specific Enthalpy ◽  
Hydrodynamic Simulations ◽  
Calculation Domain ◽  
Relativistic Jet ◽  
Material Mixing

AbstractWe investigate the growth of the Rayleigh–Taylor and Richtmyer–Meshkov instabilities at the interface of the relativistic jet using three-dimensional hydrodynamic simulations. The propagation of the relativistic jet that is continuously injected from the boundary of the calculation domain into a uniform ambient medium is solved. We find that the interface of the jet is deformed by a synergetic growth of the Rayleigh–Taylor and Richtmyer–Meshkov instabilities regardless of the launching condition, such as the specific enthalpy of the jet or the effective inertia ratio between the jet and ambient medium. The material mixing between the jet and external medium due to these instabilities causes the deceleration of the jet.

Development and Application of a 2D/1D Fusion Code With Leakage Reconstruction Method

2018 ◽  
Author(s):  
Liang Liang ◽  
Zhouyu Liu ◽  
Hongchun Wu ◽  
Sheng Wang ◽  
Qian Zhang ◽  
...  
Keyword(s):  
Difference Method ◽  
Three Dimensional ◽  
Axial Direction ◽  
Reconstruction Method ◽  
Fusion Method ◽  
Reactor Physics ◽  
Leakage Term ◽  
Calculation Domain ◽  
Transport Calculation ◽  
Transport Method

The 2D/1D fusion method (2D/1D method) is becoming a popular transport method for whole-core calculations, which reduces the group condense and assembly homogenization approximations in the conventional two-step reactor physics calculations. In most 2D/1D codes, a pin is chosen as a 1D calculation domain, which assumes that the axial leakage of the pin is flat on top/bottom surfaces. Similar to the axial leakage, the radial leakage of every 2D plane also introduces several approximations along axial direction for the 1D calculation. In this paper a 2D/1D fusion code is developed, while a leakage reconstruction method is proposed and applied. In this 2D/1D fusion code, MOC is applied to the radial 2D calculation and the Sn diamond difference method is used for the axial 1D calculation. Numerical results indicate that the 2D/1D fusion code developed in this paper is precise in three-dimensional transport calculation and show the performance of this leakage reconstruction method especially when the leakage term is significant.

Research and Experimental Verification of the Heat and Mass Transfer Models of the Spraying Cooler

2013 ◽  
Vol 448-453 ◽  
pp. 3281-3285
Author(s):  
Xiao Wei Zhou ◽  
Xin Yu Zhang ◽  
Bin Yang ◽  
Ping An Yu
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Transfer Process ◽  
Similarity Theory ◽  
Mass Transfer Process ◽  
Main Principle ◽  
Closed Cycle ◽  
Calculation Domain ◽  
Mass And Heat Transfer ◽  
Working Parameters

Cooler is an essential part of closed cycle diesel (CCD) system. Based on the main principle of mass and heat transfer of water-air system, the thesis create the cooler model and discretize the calculation domain. The kinematic, heat and mass transfer process is studied based on similarity theory. Experiments on spraying cooler under different working parameters are carried out to verify the model. The result shows that the model can describe the heat and mass transfer process in the cooler and predict the cooling effect.

scholarly journals Influence of Calculation Domain Size on Numerical Simulation Results for Complex Terrain Wind Fields

2019 ◽  
Vol 12 (2) ◽  
pp. 59-66
Author(s):  
Lian Shen ◽  
◽  
Chenglong Wei ◽  
Chunsheng Cai ◽  
Xiaoyan Liu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Complex Terrain ◽  
Domain Size ◽  
Wind Fields ◽  
Calculation Domain ◽  
Simulation Results

Calculation of Nano-Sized Particle Catcher by Ultrasonic Vibration

2011 ◽  
Author(s):  
Shinichi Nishino ◽  
Mitsuaki Ochi ◽  
Kenji Kofu
Keyword(s):  
Influenza Virus ◽  
Acoustic Wave ◽  
Pressure Distribution ◽  
Standing Wave ◽  
Ultrasonic Vibration ◽  
Particle Motion ◽  
Acoustic Pressure ◽  
The Other ◽  
Calculation Domain ◽  
Plate Velocity

Particles on the plate vibrated by ultrasonic were gathered on the node of vibration plate. Similar to this phenomenon, if two plates are set with parallel, a plate is vibrated by ultrasonic and acoustic pressure distribution is produced between the vibration and reflection plate, nano-sized particles might be collected from the air flow and air is cleaned. Although ultrasonic was applied for the liquid and remove particles, but this has not been researched for air. Then the purpose of this study is to calculate the acoustic pressure distribution between the vibration and reflection plate by using CFD, and investigate the nano-sized particle motion in acoustic pressure distribution. When standing wave between plates is calculated, acoustic wave generated by ultrasonic vibration was reflected at the reflection plate. In the case of CFD, standing wave could not be calculated because these waves disclaim each other and wave generated by a plate doesn’t reach at the other plate. Therefore acoustic wave is also produced at reflection plate, duplicate these waves from vibration and reflection plates, and standing wave between plates were obtained. About investigation for the nano-sized particle motion in acoustic pressure distribution, particles were injected into calculation domain. Particles which have the same diameter and density with influenza virus were applied in this calculation. Examination of particle’s motion and efficient condition on dust catch were calculated in case of changing parameter, for example, amplitude and frequency of vibration plate, velocity of flowing particles, concentration of particles in the flow and so on.

scholarly journals On the Kelvin Transformation in Finite Difference Implementations

Electronics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 442
Author(s):  
Gerald Gold
Keyword(s):  
Finite Difference ◽  
Analytical Solution ◽  
Difference Operators ◽  
System Of Equations ◽  
Calculation Domain ◽  
The Real ◽  
Conventional Calculation ◽  
Outer Domain ◽  
Kelvin Transformation ◽  
Delaunay Mesh

Finite difference operators were applied on a Delaunay mesh. This way it is possible to discretize a radial boundary that is used to perform a Kelvin mapping of an additional outer domain to virtually extend the computation domain to infinity. With an example two-wire problem, the performance of this approach is shown in comparison with a conventional calculation domain and with the analytical solution, respectively. The presented implementation delivers a more precise approximation to the real values and at the same time requires a smaller system of equations—i.e., allows for faster computations.

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