NUMERICAL SIMULATION OF THE COUETTE–POISSON PROBLEM WITH THE RELAX FUNCTION OF THE MATHCAD PROGRAM IN CALCULATING SCREW PRESS

2018 ◽  
Author(s):  
А.В. ГУКАСЯН ◽  
В.С. КОСАЧЕВ ◽  
Е.П. КОШЕВОЙ
Keyword(s):  
Numerical Simulation ◽  
Numerical Modeling ◽  
Screw Press ◽  
Poisson Problem ◽  
Layered Flows

Рассмотрены особенности численного моделирования слоистых течений для расчета червячных нагнетателей и определения скорости сдвига материала в сечении канала экструдера. Features of numerical modeling of layered flows for calculation of worm superchargers and determination of speed of shift of material in the section of the channel of an extruder are considered.

Mathematical Modeling of Formation of Transparency Regions in Supercooled Stratiform Clouds and Fogs

2018 ◽  
Vol 9 (1) ◽  
pp. 17
Author(s):  
Vitaly A. SHAPOVALOV ◽  
Aida A. ADZHIEVA ◽  
Lyudmila M. FEDCHENKO ◽  
Egor A. KOVALEV
Keyword(s):  
Mathematical Modeling ◽  
Numerical Simulation ◽  
Numerical Modeling ◽  
Weather Conditions ◽  
Cloud Seeding ◽  
Impact Effect ◽  
Application Rates ◽  
Stratiform Clouds ◽  
Cloud Evolution

We developed models of active influence on clouds using crystallization reagents to ensure transparency of the atmosphere. Numerical modeling of various versions of influence on stratiform clouds at aviation seeding was performed. Variation of characteristics of supercooled fogs when bringing man-made crystals was studied. The determination of reagents application rates, estimating impact effect and some other issues were solved using the results of modelling of clouds evolution (both natural and under active influence). Based on generalization of the results of numerical simulation of cloud evolution, the proposals for improvement of cloud seeding technology under different weather conditions are developed.

scholarly journals Optimal design of the solar tracking system of parabolic trough concentrating collectors

2020 ◽  
Vol 15 (4) ◽  
pp. 613-619
Author(s):  
Li Kong ◽  
Yunpeng Zhang ◽  
Zhijian Lin ◽  
Zhongzhu Qiu ◽  
Chunying Li ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Solar Radiation ◽  
Tracking System ◽  
Low Cost ◽  
Parabolic Trough ◽  
The North ◽  
Tracking Mode ◽  
Solar Tracking ◽  
East West

Abstract The present work aimed to select the optimum solar tracking mode for parabolic trough concentrating collectors using numerical simulation. The current work involved: (1) the calculation of daily solar radiation on the Earth’s surface, (2) the comparison of annual direct solar radiation received under different tracking modes and (3) the determination of optimum tilt angle for the north-south tilt tracking mode. It was found that the order of solar radiation received in Shanghai under the available tracking modes was: dual-axis tracking > north-south Earth’s axis tracking > north-south tilt tracking (β = 15°) > north-south tilt tracking (β = 45) > north-south horizontal tracking > east-west horizontal tracking. Single-axis solar tracking modes feature simple structures and low cost. This study also found that the solar radiation received under the north-south tilt tracking mode was higher than that of the north-south Earth’s axis tracking mode in 7 out of 12 months. Therefore, the north-south tilt tracking mode was studied separately to determine the corresponding optimum tilt angles in Haikou, Lhasa, Shanghai, Beijing and Hohhot, respectively, which were shown as follows: 18.81°, 27.29°, 28.67°, 36.21° and 37.97°.

scholarly journals Determination of Long Horizontal Borehole Height in Roofs and its Application to Gas Drainage

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2647
Author(s):  
Gang Wang ◽  
Cheng Fan ◽  
Hao Xu ◽  
Xuelin Liu ◽  
Rui Wang
Keyword(s):  
Numerical Simulation ◽  
Theoretical Model ◽  
Fracture Zone ◽  
Coalbed Methane ◽  
High Efficiency ◽  
Gas Drainage ◽  
Methane Drainage ◽  
Working Face ◽  
Variation Characteristics

Accurately determining the height of the gas-guiding fracture zone in the overlying strata of the goaf is the key to find the height of the long horizontal borehole in the roof. In order to determine the height, in this study we chose the 6306 working face of Tangkou Coal Mine in China as a research example and used both the theoretical model and discrete element method (DEM) numerical simulation to find the height of the gas-guiding fracture zone and applied the height to drill a long horizontal borehole in the roof of the 6303 working face. Furthermore, the borehole was utilized to deep into the roof for coalbed methane drainage and the results were compared with conventional gas drainage measures from other aspects. The height of the gas-guiding fracture zone was found to be 48.57 m in theoretical model based on the bulk coefficient and the void ratio and to be 51.19 m in the DEM numerical simulation according to the temporal and spatial variation characteristics of porosity. Taking both the results of theoretical analysis and numerical simulation into consideration, we determined that gas-guiding fracture zone is 49.88 m high and applied it to drill a long horizontal borehole deep into the roof in the 6303 working face field. Compared with conventional gas drainage measures, we found that the long horizontal borehole has the high stability, high efficiency and strong adaptability for methane drainage.

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