EFFECTS OF VENTILATION SETUPS ON AIR FLOW VELOCITY AND TEMPERATURE FIELDS IN BUS PASSENGER COMPARTMENT

2015 ◽  
Vol 77 (30) ◽  
Author(s):  
Noor Emilia Ahmad Shafie ◽  
Haslinda Mohamed Kamar ◽  
Nazri Kamsah
Keyword(s):  
Flow Velocity ◽  
Air Temperature ◽  
Numerical Study ◽  
Air Flow ◽  
Ventilation System ◽  
Temperature Fields ◽  
Passenger Compartment ◽  
Three Dimensional Model ◽  
Air Flow Velocity ◽  
Ventilation Setup

A bus compartment requires a good ventilation system to provide sufficient fresh air and a uniform air flow to passengers. This article presents a numerical study using CFD method to investigate the effects of using different ventilation setups on the air flow velocity and temperature distributions inside a passenger bus. Fluent software was used to develop a simplified three-dimensional model of a quarter section of a bus passenger compartment. Turbulent flow simulation was carried out based on a standard k-epsilon model to predict the distributions of air temperature and velocity inside the passenger compartment. The effects of two ventilation setups, namely mixing and displacement ventilations on the air temperature and air flow velocity distribution were also examined. Results of CFD simulations show that the displacement ventilation setup results in more uniform distribution of air flow velocity and air temperature inside the bus passenger compartment.

scholarly journals A numerical study for the effects of sub-channels on combined thermal and hydrodynamic effectiveness in a plate heat exchanger designed for balanced ventilation

2019 ◽  
Vol 2 (3) ◽  
pp. 381-391
Author(s):  
Murat Ünverdi ◽  
Hasan Küçük
Keyword(s):  
Flow Velocity ◽  
Numerical Study ◽  
Air Flow ◽  
Thermal Power ◽  
Hydrodynamic Performance ◽  
Channel Height ◽  
Plate Heat ◽  
Air Flow Velocity ◽  
Drop Flow ◽  
Optimal Average

In this study, the effects of the number of sub-channels on the thermal and hydrodynamic performance of plate heat exchangers (PHEs) designed to be used in balanced ventilation systems have been investigated numerically. In the design of PHEs, Taguchi method was used for 4 different effective factors (average air flow velocity, channel height, number of sub-channels and plate material) in 3 levels. Numerical analyzes of PHE models were performed with a CFD based package program. In Taguchi analysis, 2 and 6 sub-channels PHE models obtained close results (<1%) in terms of the number of sub-channels according to the selected performance parameter (combined thermal and hydrodynamic effectiveness-CTHE). And thus, the changes in recovered thermal power, pressure drop, flow effectiveness and thermal effectiveness in both PHE models were investigated depending on the average air flow velocity. According to the recovered thermal power and CTHE, it was found that the optimal average air flow velocity for both PHE models was 1.5 m/s. It has been determined that 2 sub-channels model is more advantageous in terms of thermal and hydrodynamic performance, weight and production

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 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.

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

A CFD SIMULATION OF PM1 AND CO AIR CONTAMINANTS IN A BUS PASSENGER COMPARTMENT

2015 ◽  
Vol 77 (30) ◽  
Author(s):  
Noor Emilia Ahmad Shafie ◽  
Haslinda Mohamed Kamar ◽  
Nazri Kamsah
Keyword(s):  
Carbon Monoxide ◽  
Particulate Matter ◽  
Distribution Systems ◽  
Cfd Simulation ◽  
Ventilation System ◽  
Air Distribution ◽  
Passenger Compartment ◽  
Displacement Ventilation ◽  
Three Dimensional Model ◽  
Air Contaminants

Air distribution systems inside a bus compartment are important for providing healthy and comfortable environment for passengers. Lack of ventilation inside the bus passenger compartment causes an increase level of air contaminants concentration. Particulate matters and carbon monoxide are indoor air contaminants which can affect the passenger’s health such as respiratory problem and lung cancer. This article reports the results of a CFD simulation on transport of carbon monoxide and particulate matter 1 inside a passenger compartment of a university’s shuttle bus. Fluent CFD software was used to develop a simplified three-dimensional model of the bus passenger compartment. Flow analysis was carried out using RNG k-e turbulent model for air flow, discrete phase and species transport for the air contaminants. Four variations of ventilation system namely two mixing ventilation types, combined mixing with displacement ventilation and combined mixing ventilation with underfloor air distribution was examined. The CFD simulation results show that the use of the combined mixing and displacement ventilation and also the combined mixing and underfloor ventilation types are capable of reducing the concentration of carbon monoxide and particulate matter 1 inside the bus passenger compartment by 81% and 54%, respectively.

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.

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