Natural ventilation in an enclosure induced by a heat source distributed uniformly over a vertical wall

2001 ◽  
Vol 36 (4) ◽  
pp. 493-501 ◽  
Author(s):  
Z.D Chen ◽  
Y Li ◽  
J Mahoney
Keyword(s):  
Heat Source ◽  
Natural Ventilation ◽  
Vertical Wall

Effects of wall proximity on the airflow in a vertical solar chimney for natural ventilation of dwellings

2020 ◽  
Vol 44 (3) ◽  
pp. 225-250
Author(s):  
Y Quoc Nguyen ◽  
John Craig Wells
Keyword(s):  
Heat Source ◽  
Natural Ventilation ◽  
Vertical Wall ◽  
Air Gap ◽  
Horizontal Plate ◽  
Solar Chimney ◽  
Horizontal Wall ◽  
Induced Flow ◽  
Air Channel ◽  
Wall Proximity

This study investigates performance of a vertical solar chimney, which absorbs solar energy and induces airflow for natural ventilation and cooling of dwellings, under effects of walls neighboring to its air channel. A computational fluid dynamics model was developed to predict induced flow rate and thermal efficiency of a vertical solar chimney with four types of nearby walls: a vertical wall to which the solar chimney was attached, a horizontal plate above the outlet of the air channel, a horizontal plate, and a horizontal wall below the inlet of the air channel. Examined factors included the heat flux in the air channel, the chimney height, the air gap, the distance of the walls, and the location of the heat source in the air channel. The results showed that effects of the wall proximity were modulated by the location of the heat source and the ratio G/ H between the air gap and the chimney height. Particularly, performance of the chimney was enhanced when the heat source was on the opposite side of the vertical wall and when G/ H was large.

Numerical Simulation of Natural Ventilation in Large-Scale Industrial Workshops Based on Orthogonal Test Design

2013 ◽  
Author(s):  
Yan Long ◽  
Jinming Feng ◽  
Ke Liu ◽  
Shiping Jin ◽  
Yan Fu
Keyword(s):  
Heat Source ◽  
Large Scale ◽  
Natural Ventilation ◽  
Orthogonal Test ◽  
Outdoor Environment ◽  
Industrial Plant ◽  
Test Design ◽  
Range Analysis ◽  
Orthogonal Test Design ◽  
Cfd Method

In this paper, orthogonal test design method and the CFD method were used to study the different building envelopes, and the outdoor environment of natural ventilation effect of single span of high temperature industrial workshop. Firstly, 18 ventilation models of workshop with heat source were constructed with orthogonal test design. Secondly, 18 ventilation models of workshop with heat source were simulated with CFD method. Finally, the order of the influencing factors on the ventilation of workshop was obtained through multiple index range analysis of the orthogonal experiment results according to the average temperature inside the workshop. Then the optimal combination of the best ventilation effect was selected. The research results can provide effectively theoretical basis for the future industrial plant ventilation design and optimization.

Modeling of Buoyancy-Driven Natural Ventilation in Workshop: Optimization of Distance between Heat Source and Ground

2012 ◽  
Vol 170-173 ◽  
pp. 2579-2582 ◽  
Author(s):  
Ya Xin Su ◽  
A Long Su ◽  
Xin Wan
Keyword(s):  
Heat Source ◽  
Indoor Air ◽  
Energy Cost ◽  
Lower Energy ◽  
Natural Ventilation ◽  
Waste Heat ◽  
Heat Sources ◽  
Hot Air ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method

Natural ventilation is suitable for application to workshops with heat sources to keep good indoor air quality at lower energy cost. In this paper, the authors numerically investigated the buoyancy-driven natural ventilation in a workshop with heat source based on computational fluid dynamics (CFD) method. The effect of the distance between heat source and ground on the air flow and temperature distribution was examined. Results showed that the average air temperature at operation zone could be effectively reduced when the distance between heat source and ground increased. The temperature field in the upper zone of the workshop was improved by diminishing the hot air zone near the ceiling and the waste heat directly going into the operation zone decreased when the distance between heat source and ground increased.

Impact of Partial Slip and Heat Source on MHD Mixed Convection Flow of Nanofluid in a Double Lid-Driven Cavity Containing Insulated Obstacle

2020 ◽  
Vol 9 (3) ◽  
pp. 230-241
Author(s):  
M. A. Mansour ◽  
S. Sivasankaran ◽  
A. M. Rashad ◽  
T. Salah ◽  
Hossam A. Nabwey
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Source ◽  
Mixed Convection ◽  
Vertical Wall ◽  
Partial Slip ◽  
Convection Flow ◽  
Uniform Heat Flux ◽  
Mixed Convection Flow ◽  
Left Wall

The current investigation analyzes the effects of partial slip and heat generation on the mixed convection flow with heat transfer in an inclined double lid-driven square cavity containing centered square adiabatic obstacle in the presence of magnetic field. The used cavity is subjected to constant heat flux and filled with Cu-water nanofluid. The top and bottom horizontal walls are thermally insulated and move with uniform velocity while the right vertical wall is maintained at a constant low temperature. A uniform heat flux is located in a part of th left wall of the cavity while the remaining part of this wall is thermally insulated. Finite volume technique is utilized to solve dimensionless governing equations of the problem. The proposed method is validated with the previous published numerical studies which distinctly offer a good agreement. The obtained results show that changing in the heat source length affects much the flow and thermal fields than the position of heat source. The averag Nusselt number decreases when the aspect ratio of the obstacle and heat source length increases. The heat transfer rate behaves nonlinearly with inclination of the cavity.

Small to large scale mixed turbulent convection: buildings application

2018 ◽  
Vol 28 (1) ◽  
pp. 188-205 ◽  
Author(s):  
Souad Morsli ◽  
Mustapha Boussoufi ◽  
Amina Sabeur ◽  
Mohammed El Ganaoui ◽  
Rachid Bennacer
Keyword(s):  
Flow Structure ◽  
Large Scale ◽  
Natural Ventilation ◽  
Vertical Wall ◽  
Cold Temperature ◽  
Temperate Climate ◽  
3D Flow ◽  
Content Type ◽  
Hot Temperature ◽  
The One

Purpose The use of natural ventilation by large openings to maintain thermal comfort conditions in the premises is a concept that is perfectly integrated into the traditional architecture of countries in the Mediterranean region or in tropical climates. In a temperate climate where the architecture is not usually designed to respond to the use of natural ventilation is seasonal and is done at the initiative of the occupants by making changes in the design of their doors. The European interest in natural ventilation, as a passive building air-conditioning technology, is increasing and has been the subject of a research program commissioned by the European Community. In this work, the authors consider a part of a housing compound as a refreshing floor. This floor is maintained at a constant cold temperature, the one vertical wall at hot temperature and other surfaces are adiabatic. Various scenarios are considered for this work. Mixed convection for different boundary conditions and different configurations is carried out. In addition, an airflow is injected through a window and extracted on the opposite window. Classical conclusion and transitional value on Richardson number have been completed by the new thermal configuration with nonsymmetric thermal conditions. The complex 3D flow structure is more obvious when one of the two flows (ventilation or natural convection) dominates. However, the induced heat transfer is less sensitive to the added ventilation. In this study, the authors consider a part of a housing compound as a refreshing floor. This floor is maintained at a constant cold temperature, the one vertical wall at hot temperature and other surfaces are adiabatic. Design/methodology/approach This is a qualitative preliminary study of a 2D–3D flow. The authors examine the competition between the natural convective flow and the added airflow on the flow structure and indoor air quality. The numerical model shows a good agreement with that obtained by researchers analytically and experimentally. To deal with turbulence, the RNG k-ε model has been adopted in this study. Findings The transfer is more sensitive between the 2D and 3D cases for the present analyzed case. Originality/value The study of ventilation efficiency has shown the competition between the big and small structures and the induced discomfort.

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