scholarly journals Analysis of Ventilation Efficiency in the Earth Covered Magazine for Ammunition Storage Using Numerical Simulation

2021 ◽  
Vol 1203 (2) ◽  
pp. 022069
Author(s):  
Nurin Zecevic ◽  
Jasmin Terzic ◽  
Berko Zecevic ◽  
Adis Ajanovic
Keyword(s):  
Numerical Simulation ◽  
Relative Humidity ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Experimental Studies ◽  
Environmental Parameters ◽  
Airflow Velocity ◽  
Ansys Fluent ◽  
Rapid Decomposition ◽  
Negative Effect

Abstract Internal environment parameters such as temperature, relative humidity and airflow velocity in ammunition storage facilities have a significant impact on the condition and overall life of ammunition, especially on the process of ammunition degradation in situations when their values deviate from required standards for safe storage. High temperatures inside the magazine, as well as in the ammunition packaging, can have a very negative effect on the structure of ammunition and explosives, and high values of relative humidity can result in corrosion and rapid decomposition of chemical compounds. Therefore, a properly designed ventilation system should ensure that the values of internal temperature and relative humidity are within the permitted limits, which is a very important aspect of the storage process itself, so that ammunition and explosives can be completely safe and ready for transport, use and handling. Experimental studies conducted in several magazines of ammunition and explosives in Bosnia and Herzegovina (BiH), had aim to monitor changes of environmental parameters such as temperature, relative humidity and airflow velocity. During these experimental measurements, high values of relative humidity were in these magazines observed, as well as uneven airflow in some ventilation ducks. The main cause of such measured values can be related to the inadequate performance of the natural ventilation system of the analysed magazines. Using numerical simulations (finite volume method) in the ANSYS – Fluent program, the analysis of the existing ventilation system of earth covered magazine in BiH from the aspect of airflow velocity was performed, as well as analysis of modifications that can improve airflow within the analysed magazine. The results of numerical simulation for the existing state of analysed magazine corresponded to the results of airflow measurements at certain places in the magazine. It was confirmed that the existing ventilation system does not provide proper ventilation, which further causes higher relative humidity values. The results of numerical simulation for the proposed modifications of the ventilation system have shown significantly better air circulation in the magazine, i.e. that a more efficient natural ventilation was achieved.

scholarly journals Three-Dimensional Simulation of Wind-Driven Ventilation Through a Windcatcher With Different Inlet Designs

2019 ◽  
Vol 12 (4) ◽  
Author(s):  
Peter Abdo ◽  
Rahil Taghipour ◽  
B. Phuoc Huynh
Keyword(s):  
Wind Speed ◽  
Average Velocity ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Three Dimensional ◽  
Cfd Modeling ◽  
Ansys Fluent ◽  
Wind Velocities ◽  
Dimensional Simulation ◽  
Convergent Inlet

Abstract Windcatcher is an effective natural ventilation system, and its performance depends on several factors including wind speed and wind direction. It provides a comfortable and healthy indoor environment since the introduced fresh air decreases the moisture content and reduces the pollutant concentration. Since the wind speed and its direction are generally unpredictable, it is important to use special inlet forms and exits to increase the efficiency of a windcatcher. In this study, computational fluid dynamics (CFD) modeling is implemented using ansys fluent to investigate the airflow entering a three-dimensional room through a windcatcher with different inlet designs. Three designs are studied which are a uniform inlet, a divergent inlet, and a bulging-convergent inlet. The airflow pattern with all inlets provided adequate ventilation through the room. With all the applied wind velocities (1, 2, 3, and 6 m/s) at the domain's inlet, the divergent inlet shape has captured the highest airflow through the room and provided higher average velocity at 1.2 m high enhancing the thermal comfort where most of the human occupancy occurs. With 6 m/s wind velocity, the divergent inlet has captured 2.55% more flow rate compared to the uniform inlet and 4.70% compared to the bulging-convergent inlet, and it has also provided an average velocity at 1.2 m high in the room of 7.16% higher than the uniform inlet and 8.44% higher than the bulging-convergent inlet.

scholarly journals Living quarters. A natural balanced ventilation system. Simulations part 1

2018 ◽  
Vol 49 ◽  
pp. 00025 ◽  
Author(s):  
Tomasz Gaczoł
Keyword(s):  
Natural Ventilation ◽  
Residential Buildings ◽  
Ventilation System ◽  
Comfort Level ◽  
Test Results ◽  
Pressure System ◽  
Ansys Fluent ◽  
Short Supply ◽  
Air Exchange Rate ◽  
Exhaust Duct

In the following article the author proposes the solution for a properly functioning natural ventilation system based on the use of supply and exhaust ducts, i.e. by designing a natural balanced ventilation system. The paper is devoted to test results of air flow through natural ventilation supply-exhaust ducts in the rooms located on the lower floor of the building. The simulations conducted in ANSYS Fluent software relate to such issues as: pressure system inside the room and in the exhaust duct, distribution of air temperatures in the room, vector direction of airflow through supplyexhaust ducts and in the analysed room. Three types of solutions were selected for the tests: air inflow into the room through the air intake located at the basement level, air inflow through the window ventilator (although no longer used, this solution can be found in many existing residential buildings) and the natural ventilation system supported with the so-called “solar chimney”. All simulations were conducted with an outdoor temperature of +3 degrees C. The indoor temperature is + 20 degrees C, considered to be the minimum thermal comfort level. In the era of common building sealing, the presented ventilation system may be a good solution that guarantees proper functioning of natural ventilation. In all cases presented, it meets the normative regulations and requirements for the ventilation air stream and the air exchange rate in the room. The paper (first part) describes test results concerning the room located on the lower floor of the building, i.e. with a short supply duct and a 12-meter long exhaust duct.

scholarly journals ANALYSIS OF AIR FLOW DISTRIBUTION IN RESIDENTIAL ROOMS WITH SUPPLY WINDOW VALVES BY MATHEMATICAL MODELING IN ANSYS FLUENT

2019 ◽  
Vol 4 (10) ◽  
pp. 67-73
Author(s):  
О. Симбирев ◽  
O. Simbirev
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Natural Ventilation ◽  
Residential Buildings ◽  
Ventilation System ◽  
Flow Distribution ◽  
Ansys Fluent ◽  
Airflow Distribution ◽  
Standard Values ◽  
Technical Solutions

The main problem highlighted in the article is the deviation of the microclimate parameters from the standard values due to the improper organization of airflow in the residential rooms of apartment buildings. The objective is to obtain a working mathematical model of the natural ventilation system, its study for optimization or modernization. The analysis of the normative literature, scientific works of domestic and foreign scientists, developments in the field of natural ventilation and ventilation of residential buildings is carried out. A mathematical model of air exchange of a residential room with convection is presented and analyzed. The flow rate and air temperature, the temperature on the surface of the heater are set as boundary conditions when creating a mathematical model. The features and regularities of airflow distribution in the room obtained as a result of mathematical modeling are revealed. The distributions of air velocity in the room are given. Difficulties of the organization of effective natural inflow of air and the problems with design of valves of infiltration are designated. Technical solutions aimed at improving the quality of indoor microclimate and energy saving are proposed.

scholarly journals Design of a Passive Downdraught Evaporative Cooling Windcatcher (PDEC-WC) System for Greenhouses in Hot Climates

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2934 ◽  
Author(s):  
Marouen Ghoulem ◽  
Khaled El Moueddeb ◽  
Ezzedine Nehdi ◽  
Fangliang Zhong ◽  
John Calautit
Keyword(s):  
Relative Humidity ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Evaporative Cooling ◽  
Cross Flow ◽  
Flow Distribution ◽  
Average Error ◽  
Ambient Conditions ◽  
Mass Flow Rates ◽  
Computational Fluid Dynamics Cfd

A windcatcher is a wind-driven natural ventilation system that catches the prevailing wind to bring fresh airflow into the building and remove existing stale air. This technology recently regained attention and is increasingly being employed in buildings for passive ventilation and cooling. The combination of windcatchers and evaporative cooling has the potential to reduce the amount of energy required to ventilate and cool a greenhouse in warm and hot climates. This study examined a greenhouse incorporated with a passive downdraught evaporative cooling windcatcher (PDEC-WC) system using Computational Fluid Dynamics (CFD), validated with experimental data. Different hot ambient conditions of temperature (30–45 °C) and relative humidity (15–45%) were considered. The study explored the influence of different spray heights, layouts, cone angles and mass flow rates on indoor temperature and humidity. The average error between measurements and simulated results was 5.4% for the greenhouse model and 4.6% for the evaporative spray model. Based on the results and set conditions, the system was able to reduce the air temperature by up to 13.3 °C and to increase relative humidity by 54%. The study also assessed the influence of neighbouring structures or other greenhouses that influence the flow distribution at the ventilation openings. The study showed that the windcatcher ventilation system provided higher airflow rates as compared to cross-flow ventilation when other structures surrounded the greenhouse.

scholarly journals Simulation of Naturally Ventilated Underground Car Park with CFD

2020 ◽  
Vol 3 (SI3) ◽  
pp. SI22-SI28
Author(s):  
Huong Mai Thi Nguyen ◽  
Trương Tích Thiện
Keyword(s):  
Fire Safety ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Urban Land ◽  
Navier Stokes ◽  
Ansys Fluent ◽  
Car Park ◽  
Effective Ventilation ◽  
Fire And Explosion ◽  
Cfd Method

Nowadays, the speed of urbanization is increasing rapidly, so the urban land area is fully utilized to build high-rise buildings, apartments, and commercial centers, and thus, the car tunnel parking and basement parking basements also become more popular. However, apartment fire and explosion, especially car fire and explosion is an extremely important issue that must be concerned in construction design. Therefore, it is essential to design an effective ventilation system in the parking basement when a fire occurs an effective ventilation system for the tunnel is really necessary for basement firefighting. When building up the car park, the importance is not only a reasonable architecture but also the ventilation and air quality of the tunnel because it directly affects human health. Decades ago, scientists had studied the solution to ventilate the car park. The computational fluid dynamics (CFD) method is also applied to determine the pressure and velocity intensity for buildings that detect residuals in architecture, thereby improving and providing a superior solution. More for this problem. Many studies related to this issue have been published internationally. Jiang (Jiang, Allocca, & Chen, 2004) also investigated natural ventilation by using Reynolds Averaged Navier - Stokes turbulence model (RANS). Khalil (Khalil, Shoukry, H.A, & Harridy, 2015) also examined the distribution of CO emissions from buses in a basement in Cairo using ANSYS FLUENT software.The basement car park is a popular solution to effectively use urban land, especially in commercial centers and apartments. However, the situation of apartment fire and explosion is a hot problem, partly due to the tunnel ventilation has not met the requirements of fire safety. Therefore, the design of the car park basement ensures fire safety as well as bring comfort to people. In this study, the problem of basement temperature and wind velocity by natural ventilation method will be analyzed and evaluated in accordance with ADPI standard and Carbon monoxide concentration with WHO standard to identify areas of unsatisfactory temperature and velocity to reasonably adjust and propose other suitable ventilation options.

scholarly journals Investigation of a Ventilation System for Energy Efficiency and Indoor Environmental Quality in a Renovated Historical Building: A Case Study

2019 ◽  
Vol 16 (21) ◽  
pp. 4133 ◽  
Author(s):  
Richard Nagy ◽  
Ľudmila Mečiarová ◽  
Silvia Vilčeková ◽  
Eva Krídlová Burdová ◽  
Danica Košičanová
Keyword(s):  
Energy Consumption ◽  
Relative Humidity ◽  
Environmental Quality ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Sick Building Syndrome ◽  
Co2 Concentration ◽  
Indoor Environmental Quality ◽  
Historical Building ◽  
The Mean

This paper emphasizes the importance of environmental protection regarding the reduction of energy consumption while maintaining living standards. The aim of the research is to observe the effects of mechanical and natural ventilation on energy consumption and building operation as well as indoor environmental quality (IEQ). The results of indoor environmental quality testing show that the mean relative humidity (31%) is in the permissible range (30%–70%); the mean CO2 concentration (1050.5 ppm) is above the recommended value of 1000 ppm according to Pettenkofer; and the mean PM10 concentration (43.5 µg/m3) is under the limit value of 50 µg/m3. A very large positive correlation is found between relative humidity and concentration of CO2 as well as between the concentration of PM5 and the concentration of CO2. The most commonly occurring sick building syndrome (SBS) symptoms are found to be fatigue and the feeling of a heavy head.

Investigation on Air Quality in Strawberry Greenhouse under Natural Ventilation

2014 ◽  
Vol 675-677 ◽  
pp. 382-387
Author(s):  
Wei Hong Fu ◽  
Shi Jun You
Keyword(s):  
Numerical Simulation ◽  
Temperature Field ◽  
Natural Ventilation ◽  
General Trend ◽  
Environmental Parameters ◽  
Air Velocity ◽  
Indoor Temperature ◽  
Air Inlet ◽  
Simulation And Experiment ◽  
The Impact

The effect of the air inlet and the air outlet of the strawberry greenhouse are very significant to the microclimate in greenhouse under the conditions of natural ventilation. This paper studied the numerical simulation and experiment of indoor temperature field of the strawberry greenhouse with natural ventilation in different areas of air inlet and air outlet. The impact of the natural ventilation on the microclimate of strawberry greenhouse has been explored. The results indicated that the air velocity and temperature in the air inlet effected on the temperature distribution within the greenhouse, and the temperature near the air inlet was susceptible to the outdoor environmental parameters. The general trend of the variation of the indoor temperature in the greenhouse decreased with increasing the sizes of the air inlet and the air outlet. The overall trend of temperature gradient is similar within the greenhouse.

Thermal Performance of a Natural Ventilation System

2010 ◽  
Author(s):  
M. J. Jime´nez ◽  
J. D. Guzma´n ◽  
M. R. Heras ◽  
J. Arce ◽  
J. P. Xama´n ◽  
...  
Keyword(s):  
Thermal Effects ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Experimental Studies ◽  
Design Parameters ◽  
Ambient Conditions ◽  
Solar Chimney ◽  
Concrete Wall ◽  
Reinforced Concrete Wall ◽  
One Year

Natural ventilation in buildings using solar passive systems, such as solar chimneys, has emerged in the last years. Several theoretical and experimental studies in the literature show that their design parameters strongly depend on the ambient conditions, in which they are installed. In order to increase the knowledge of this kind of systems, this work presents the thermal behavior of a stand alone experimental solar chimney during one year. The dimensions of the solar chimney are 5.60 m high, 1.0 m width, and 0.52 m depth. The absorber plate is made of a common reinforced concrete wall of 4.5 m high, 1.0 m wide and 0.15 m depth. This system was designed by Marti´ J., and Heras M.R. in 2003 [1,2] and it is located in the Laboratorio de Ensayos Energe´ticos para Componentes de la Edificacio´n (LECE) in the Plataforma Solar of Almeri´a (PSA) in Spain. The entrance of this solar chimney was redesigned in 2007 by Arce et al. [3] and also the instrumentation of the system was increased and improved. During one year, the solar chimney was monitored and several experimental variables were measured. The results present the temperature profiles of the different measured elements of the solar chimney as well as the air mass flow rate through the solar chimney channel. It was observed that the effect of the outdoor wind added to the thermal effects plays an important role affecting the performance of the solar chimney studied.

scholarly journals The Influence of Meshing Strategies on The Numerical Simulation of Solar Greenhouse Dryer

2021 ◽  
Vol 947 (1) ◽  
pp. 012007
Author(s):  
Viet. T. Tran ◽  
Yen. H.P. Duong ◽  
Tan M. Le
Keyword(s):  
Numerical Simulation ◽  
Temperature Distribution ◽  
Relative Humidity ◽  
Mesh Generation ◽  
Optimum Conditions ◽  
Ansys Fluent ◽  
Solar Greenhouse ◽  
Hexahedral Meshing ◽  
Fluent Software ◽  
Tetrahedral Meshing

Abstract In the present study, we conduct the numerical simulation for solar greenhouse dryer performance by Ansys Fluent software. The numerical simulations compared the meshing strategies for the dryer and show the effects on both temperature distribution and relative humidity distribution of air inside the dryer. Unstructured meshes were used in the numerical simulation employing hexahedral meshing and tetrahedral meshing for mesh generation. The meshing strategies were evaluated through 2 size of cell i.e., 0.1 m and 0.05m. The results indicated that the size of cell have strong effect than the mesh type on the temperature profile and humidity of air inside the dryer. Thus, the results gave the engineers more options to select the optimum conditions for meshing and simulation the dryer.

The Numerical Simulation of Thermal Environment of Strawberry Greenhouse in Natural Ventilation

2014 ◽  
Vol 501-504 ◽  
pp. 2276-2281 ◽  
Author(s):  
Wei Hong Fu ◽  
Shi Jun You
Keyword(s):  
Numerical Simulation ◽  
Wind Speed ◽  
Air Temperature ◽  
Natural Ventilation ◽  
Thermal Environment ◽  
Environmental Parameters ◽  
Outdoor Air ◽  
Air Velocity ◽  
Indoor Thermal Environment ◽  
Average Temperature

The method of numerical simulation was adopted in this study to explore the size of the natural ventilation inlet opening, outdoor temperature and ambient wind speed and other environmental parameters to effect of the varied rules of thermal environment of the strawberry solar greenhouse. The variation of outdoor air temperature effected greatly to the indoor thermal environment, the average air velocity in the strawberry growing zoon within the greenhouse was rose initially and dropped tend to the steady with increasing outdoor air temperature. The average temperature in the strawberry growing zoon was decreased with increasing the outside wind speed. The average air velocity was increased gradually in the strawberry growing zoon within the greenhouse with increasing outdoor wind speed. The average velocity was reduced gradually toward to constant.

Sign in / Sign up

Export Citation Format

Share Document