scholarly journals Improving the efficiency of carousel wind turbine using aerodynamic shield

2021 ◽  
Vol 2119 (1) ◽  
pp. 012093
Author(s):  
A F Serov ◽  
V N Mamonov ◽  
A D Nazarov ◽  
N B Miskiv
Keyword(s):  
Kinetic Energy ◽  
Flow Velocity ◽  
Air Flow ◽  
Cylindrical Body ◽  
Vertical Axis ◽  
Rotor Blades ◽  
Heat Generator ◽  
Axis Of Rotation ◽  
Wheel Torque ◽  
Air Flow Velocity

Abstract The problem of increasing the efficiency of using the oncoming air flow for a wind wheel with a vertical axis of rotation, which is a mechanical drive of the wind heat generator, is considered. It is proposed to increase the efficiency of the device by installing an aerodynamic shield for the air flow oncoming the wind wheel. Such a shield is a cylindrical body in which a heat generator is placed. The shield creates an effect of confuser, leading to an increase in the speed and, consequently, in the kinetic energy of the air flow acting on the rotor blades. It is shown experimentally that the presence of an aerodynamic shield under the conditions of the experiments carried out at an incoming air flow velocity of ~ 1 m/s leads to a practical doubling of the wind wheel torque.

EXPERIMENTAL AND ANALYTICAL STUDIES OF VERTICAL AXIS WIND TURBINES

2018 ◽  
pp. 51-58
Author(s):  
B. P. Khozyainov
Keyword(s):  
Wind Turbine ◽  
Flow Velocity ◽  
Wind Power ◽  
Wind Turbines ◽  
Power Efficiency ◽  
Air Flow ◽  
Geometrical Parameters ◽  
Wind Speeds ◽  
Analytical Studies ◽  
Air Flow Velocity

The article carries out the experimental and analytical studies of three-blade wind power installation and gives the technique for measurements of angular rate of wind turbine rotation depending on the wind speeds, the rotating moment and its power. We have made the comparison of the calculation results according to the formulas offered with the indicators of the wind turbine tests executed in natural conditions. The tests were carried out at wind speeds from 0.709 m/s to 6.427 m/s. The wind power efficiency (WPE) for ideal traditional installation is known to be 0.45. According to the analytical calculations, wind power efficiency of the wind turbine with 3-bladed and 6 wind guide screens at wind speedsfrom 0.709 to 6.427 is equal to 0.317, and in the range of speed from 0.709 to 4.5 m/s – 0.351, but the experimental coefficient is much higher. The analysis of WPE variations shows that the work with the wind guide screens at insignificant average air flow velocity during the set period of time appears to be more effective, than the work without them. If the air flow velocity increases, the wind power efficiency gradually decreases. Such a good fit between experimental data and analytical calculations is confirmed by comparison of F-test design criterion with its tabular values. In the design of wind turbines, it allows determining the wind turbine power, setting the geometrical parameters and mass of all details for their efficient performance.

Numerical Study on the Surface Convective Heat Transfer of Mass Concrete Structure

2015 ◽  
Vol 723 ◽  
pp. 992-995
Author(s):  
Biao Li ◽  
Fu Guo Tong ◽  
Chang Liu ◽  
Nian Nian Xi
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Flow Velocity ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Air Flow ◽  
Convective Heat Transfer Coefficient ◽  
Concrete Surface ◽  
Mass Concrete ◽  
Air Flow Velocity

The surface convective heat transfer of mass concrete is an important element of concrete structure temperature effect analysis. Based on coupled Thermal Fluid governing differential equation and finite element method, the paper calculated and analyzed the dependence of the concrete surface convective heat transfer on the air flow velocity and the concrete thermal conductivity coefficient. Results show that the surface convective heat transfer coefficient of concrete is a quadratic polynomial function of the air flow velocity, but influenced much less by the air flow velocity when temperature gradient is dominating in heat transfer. The concrete surface convective heat transfer coefficient increases linearly with the thermal conductivity of concrete increases.

scholarly journals Effect of the fuel-air flow velocity on heat release rate of swirling non-premixed methane flames

2019 ◽  
Vol 95 ◽  
pp. 105465 ◽  
Author(s):  
Kuanliang Wang ◽  
Fei Li ◽  
Pengfei Zou ◽  
Xin Lin ◽  
Ronghai Mao ◽  
...  
Keyword(s):  
Heat Release ◽  
Flow Velocity ◽  
Heat Release Rate ◽  
Release Rate ◽  
Air Flow ◽  
Methane Flames ◽  
Air Flow Velocity

scholarly journals The effect of evaporative cooling on climatic parameters in a stable for sows

2014 ◽  
Vol 60 (Special Issue) ◽  
pp. S85-S91 ◽  
Author(s):  
Ľ. Botto ◽  
J. Lendelová ◽  
A. Strmeňová ◽  
T. Reichstädterová
Keyword(s):  
Flow Velocity ◽  
Indoor Air ◽  
Cooling System ◽  
Air Flow ◽  
Evaporative Cooling ◽  
Apparent Temperature ◽  
Climate Index ◽  
Pressure System ◽  
Indoor Air Flow ◽  
Air Flow Velocity

The aim of this study was to find out the effect of indirect evaporative cooling on microclimatic parameters in a stable for sows. A high-pressure system was used for cooling, the nozzles sprayed water into the outside air before its entering into the building. Temperature-humidity index during cooling was higher by 0.9 than in the section without cooling (P < 0.001). Due to low indoor air flow velocity (below 0.18 m/s), a change in apparent temperature by the Comprehensive Climate Index (CCI) was only 1.94°C. It would be possible to provide markedly better cooling effectiveness by increasing the air velocity up to 2 m/s, which may improve the CCI by 19.8% and thus to achieve better environmental conditions for housed sows. The efficiency of evaluated evaporative cooling system was moderate because the nozzles were placed outdoors and only part of humidified and cooled air was drawn into the building through inlet openings, and also because the indoor air-flow velocity was low.

Experimental Study on Heat and Mass Transfer of Millet in a Fixed Furnace

2017 ◽  
Vol 13 (1) ◽  
Author(s):  
Conghui Gu ◽  
Zhulin Yuan ◽  
Yaming Yan ◽  
Dengshan Luo ◽  
Bin Li ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Moisture Content ◽  
Flow Velocity ◽  
Heat And Mass Transfer ◽  
Wall Temperature ◽  
Air Flow ◽  
Significant Drop ◽  
Drying Characteristics ◽  
Series Of Experiments ◽  
Air Flow Velocity

Abstract A series of experiments on the heat and mass transfer of millet particles are conducted in order to demonstrate the effects on drying characteristics of particles in this work. Experimental results illustrate that thermal conductivity between particles is significantly influenced by temperature and moisture content of millet particles. The temperature of particles in axial and radial direction increases because of the increase of inner wall temperature and decreases with the increase of air flow velocity. Moreover, the moisture content of particles near the inner wall has experienced a significant drop with the increase of inner wall temperature. As a consequence, the increase of air flow velocity results from the decrease of particles moisture content and drying rate of particles increases due to the increase of air flow velocity. Furthermore, the accumulated height of particles has barely influenced on the drying characteristics of millet particles.

Creating a set of standards for air flow velocity

1990 ◽  
Vol 33 (3) ◽  
pp. 237-242
Author(s):  
B. S. Dubov ◽  
V. A. Kuz'min ◽  
A. N. Petunin ◽  
M. D. Uzdin ◽  
G. K. Shapovalov
Keyword(s):  
Flow Velocity ◽  
Air Flow ◽  
Air Flow Velocity
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