scholarly journals Construction Network Ventilation System for Underground LPG Storage Cavern

2018 ◽  
Vol 4 (7) ◽  
pp. 1521 ◽  
Author(s):  
Fang Lin
Keyword(s):  
Ventilation System ◽  
Ventilation Network ◽  
Road Tunnel ◽  
Axial Fan ◽  
Completion Status ◽  
Co Concentration ◽  
Ventilation Technique ◽  
Fluent Software ◽  
Ventilation Performance ◽  
Two Stages

Construction ventilation system is divided into two stages based on completion status of shafts in the underground petroleum storage project in Jinzhou, China. With the help of theoretical analysis and numerical simulations by using FLUENT software, in the first stage, reasonable construction ventilation is designed and cases with different outside temperature are discussed to investigate the effect of ventilation performance. It is found that with temperature difference increases, peak value of CO concentration, exhausting time of dirty air and required time to meet the CO concentration qualification decrease, but the influence degree is quite limited. Gallery-type network ventilation technique (GNVT) refined from theories of operation ventilation for road tunnel and mining ventilation network, is proposed to conduct the second stage construction ventilation. Ventilation performance of different ventilation schemes with various shafts’ states and diverse arrangements of fans are also analyzed in this study. It turns out that Axial-GNVT with shafts taking in fresh air and access tunnel ejecting dirty air has much better performance than traditional forced ventilation from access tunnel. Improved energy saving scheme is finally adopted to guide the construction. In addition, it is worth mentioning that there is no need to build middle ventilation shafts and construct shafts as large and long as possible. Field test of wind speed, dust, poisonous gas, atmospheric pressure, temperature are performed to detect ventilation effectiveness. Reduction coefficient =0.69is obtained from the test results in consideration of super-large section and it also indicates that there is no difference if the axial fan is at the shaft mouth or in the bottom.

Theoretical Analysis of Longitudinal Ventilation System in a Road Tunnel for Predictive Control Based on Inertia Effect

2013 ◽  
Vol 639-640 ◽  
pp. 665-669 ◽  
Author(s):  
Zhen Tan ◽  
Zhi Yi Huang ◽  
Ke Wu ◽  
Lei Ting Xu
Keyword(s):  
Theoretical Analysis ◽  
Predictive Control ◽  
Ventilation System ◽  
Settling Time ◽  
Step Response ◽  
Inertia Effect ◽  
Road Tunnel ◽  
Longitudinal Ventilation ◽  
Road Tunnels ◽  
Co Concentration

Speed control of longitudinal ventilation systems in road tunnels is being combined with typical model predictive control (MPC) strategies which may bring huge energy saving potential to the system. Theoretical analysis of the inertia effect is presented based on the energy equation of one dimensional incompressible unsteady flow, step response model is chosen to describe the dynamic behaviors of the system. The results show that the effect of jet speed change on CO concentration is nonlinear within fan’s economical working range and the settling time of CO level has similar change trend with that of the flow field but is a little longer. The system settling time is longer when jet speed decreases than it increases and is related to the change extent of jet speed. The effect of traffic intensity on CO concentration can be regarded as linear disturbance to the system output. These results may provide useful indexes to control the tunnel ventilation system more economically and lay foundation for the application of predictive control strategy in the system.

scholarly journals Ventilation performance and pollutant flow in a unidirectional-traffic road tunnel

2017 ◽  
Vol 21 (suppl. 3) ◽  
pp. 783-794 ◽  
Author(s):  
Milan Sekularac ◽  
Novica Jankovic ◽  
Petar Vukoslavcevic
Keyword(s):  
Velocity Distribution ◽  
Ventilation System ◽  
Numerical Approach ◽  
Temperature Fields ◽  
Laboratory Model ◽  
Road Tunnel ◽  
Tunnel Fire ◽  
Starting Point ◽  
Road Tunnels ◽  
Ventilation Performance

To develop a reliable method for modeling fire case scenarios within the road tunnels and observing the effects of the skewed velocity, experimental and numerical approach is used. Experimental results obtained from a laboratory tunnel model installation, are used to define geometry and boundary conditions. The result for the overall ventilation performance is compared to the available cases, for empty tunnel and stationary bi-directional vehicle traffic. For a unidirectional traffic road tunnel, in traffic loaded conditions, with a ventilation system based on axial ducted fans, the numerical simulation is used to determine the flow and temperature fields, the ventilation efficiency (efficiency of momentum transfer), and to assess the shape of the velocity distribution. The effect that a skewed velocity distribution can have on the resulting thermal and pollutant fields (CO2), smoke backlayering and stratification, is evaluated using numerical simulations, for the model-scale tunnel fire conditions. The effect of two possible limiting shapes of the velocity distribution, dependent only on the location of the fire with respect to the nearest upstream operating fans, is analyzed. The numerical results for a fire are scenario are a starting point in assessing the feasibility of a laboratory model fire-scenario experiment, what is planned as the next step in this research.

Numerical and Experimental Modeling of Indoor Air Quality Inside a Conditioned Space with Mechanical Ventilation and DX-Air Conditioner

2020 ◽  
Vol 38 (9A) ◽  
pp. 1257-1275
Author(s):  
Wisam M. Mareed ◽  
Hasanen M. Hussen
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Ventilation System ◽  
Thermal Conditions ◽  
Airflow Rate ◽  
Air Conditioner ◽  
Breathing Zone ◽  
Lecture Room ◽  
Ventilation Performance

 Elevated CO2 rates in a building affect the health of the occupant. This paper deals with an experimental and numerical analysis conducted in a full-scale test room located in the Department of Mechanical Engineering at the University of Technology. The experiments and CFD were conducted for analyzing ventilation performance. It is a study on the effect of the discharge airflow rate of the ceiling type air-conditioner on ventilation performance in the lecture room with the mixing ventilation. Most obtained findings show that database and questionnaires analyzed prefer heights between 0.2 m to 1.2 m in the middle of an occupied zone and breathing zone height of between 0.75 m to 1.8 given in the literature surveyed. It is noticed the mismatch of internal conditions with thermal comfort, and indoor air quality recommended by [ASHRAE Standard 62, ANSI / ASHRAE Standard 55-2010]. CFD simulations have been carried to provide insights on the indoor air quality and comfort conditions throughout the classroom. Particle concentrations, thermal conditions, and modified ventilation system solutions are reported.

COMPARISON BETWEEN LONGITUDINAL VENTILATION SYSTEM AND POINT EXTRACTION SYSTEM IN ROAD TUNNEL FIRE SAFETY

2021 ◽  
Vol 77 (1) ◽  
pp. 41-59
Author(s):  
Ti-Sheng HUANG ◽  
Nobuyoshi KAWABATA ◽  
Miho SEIKE ◽  
Masato HASEGAWA ◽  
Futoshi TANAKA ◽  
...  
Keyword(s):  
Fire Safety ◽  
Ventilation System ◽  
Extraction System ◽  
Road Tunnel ◽  
Tunnel Fire ◽  
Longitudinal Ventilation

scholarly journals Measurements and fire simulation models in road tunnels

2018 ◽  
Vol 196 ◽  
pp. 04077 ◽  
Author(s):  
Peter Danišovič ◽  
Juraj Šrámek ◽  
Michal Hodoň ◽  
Ján Glasa ◽  
Peter Weisenpacher ◽  
...  
Keyword(s):  
Ventilation System ◽  
Simulation Models ◽  
Project Schedule ◽  
Road Tunnel ◽  
Safety Equipment ◽  
In Situ Experiment ◽  
Emergency Event ◽  
Road Tunnels ◽  
Tunnel Safety

Ventilation system of road tunnel is one of the most important parts of the tunnel safety equipment, especially in view of the emergency event in the tunnel with fire. Last year we presented the testing and the first in situ measurements of our project entitled “Models of formation and spread of fire to increase safety of road tunnels”. With regard to our project schedule we performed also the second in situ experiment. Other part of this paper deals with computer simulations of fires of a selected Slovak road tunnel.

scholarly journals Road Tunnel Axial Fan Performance In Situ Test: Taking Qinling Zhongnan Mountain Highway Tunnel as an Example

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Yongdong Wang ◽  
Xingbo Han ◽  
Tianyue Zhou ◽  
Zhiwei He ◽  
Feilong Tian ◽  
...  
Keyword(s):  
Spline Interpolation ◽  
Road Tunnel ◽  
Axial Fan ◽  
In Situ Test ◽  
The Road ◽  
Highway Tunnel ◽  
Fitting Method ◽  
Axial Fans ◽  
Biharmonic Spline Interpolation

Axial fans play a pivotal role in the road tunnel ventilation system. Qualified performance of the axial fan is important for both safety and air quality maintenance reasons. Axial fans performance in situ test of Qinling Zhongnan Mountain highway tunnel, the second longest road tunnel in the world, is presented in this research. Performance test items and the qualification criterion, as well as a general framework for the road tunnel axial fan assessment, are recommended. Log-Tchebycheff method is suggested to confirm the location for the measuring lines and points. The precision of the log-Tchebycheff method in air flow rate measuring is verified by comparing with the biharmonic spline interpolation fitting result. The research shows that the log-Tchebycheff method has high precision and good efficiency in the air flow rate measurement of the road tunnel air duct. What is more, the biharmonic spline interpolation fitting method can be applied to obtain a more accurate result. The number of interpolation points of the biharmonic spline interpolation fitting method should be bigger than 2000 to provide quality results.

scholarly journals Numerical Study of Smoke Propagation in a Simulated Fire in a Wagon Within a Subway Tunnel

2008 ◽  
Author(s):  
Felipe Vittori ◽  
Luis Rojas-Solo´rzano ◽  
Armando J. Blanco ◽  
Rafael Urbina
Keyword(s):  
Numerical Study ◽  
Ventilation System ◽  
Road Tunnel ◽  
Subway Tunnel ◽  
Longitudinal Ventilation ◽  
Emergency Ventilation ◽  
Tunnel Section ◽  
Fire Scenarios ◽  
Subway Stations ◽  
Set Up

This work deals with the numerical (CFD) analysis of the smoke propagation during fires within closed environments. It is evaluated the capacity of the emergency ventilation system in controlling the smoke propagation and minimizing the deadly impact of an eventual fire in a wagon within the Metro de Caracas subway tunnel on the passengers safety. For the study, it was chosen the tunnel section between Teatros and Nuevo Circo subway stations, which consists of two parallel independent twin tunnels, connected through a transverse passage. The tunnels are provided by a longitudinal ventilation system, integrated by a set of reversible fans located at both ends of the tunnels. Three stages were considered in the study: (a) Model set up; (b) Mesh sensitivity analysis; (c) Validation of the physical-numerical parameters to be used in the numerical model; and (d) Simulation of fire scenarios in Metro de Caracas subway stations. Stages (b)–(c), aimed to testing and calibrating the CFD tool (ANSYS-CFX10™), focused on reproducing experimental data from Vauquelin and Me´gret [1], who studied the smoke propagation in a fire within a 1:20 scale road tunnel. Stage (d) critical scenarios were established via a preliminary discussion with safety experts from Metro de Caracas, in order to reduce the computer memory and the number of simulations to be performed. The analyses assessed the reliability of escape routes and alternative paths for the evacuation of passengers. Additionally, the smoke front movement was particularly computed, as a function of time, in order to determine the possible presence of the “backlayering” phenomenon [5]. Results demonstrate the strengths and weaknesses of the current ventilation system in the event of a fire in the subway tunnel, and suggest new strategies to address this potentially lethal event to minimize the risks for passengers.

Underground Research Laboratories in Japan: What Are the Important Factors for Facilities Design?

2003 ◽  
Author(s):  
T. Sato ◽  
S. Mikake ◽  
M. Sakamaki ◽  
K. Aoki ◽  
S. Yamasaki ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Sedimentary Rock ◽  
Mechanical Stability ◽  
Ventilation System ◽  
Sedimentary Rocks ◽  
Crystalline Rock ◽  
Ventilation Network ◽  
Main Stage ◽  
Middle Stage ◽  
Ventilation Shaft

This paper describes the current status of two Japanese off-site Underground Research Laboratories (URLs) Projects, one for crystalline rock and the other for sedimentary rock. This paper is focused on mechanical stability and ventilation, important factors relevant to the design and construction of deep underground facilities. High-pressure inflow, another important factor, will be included in the URL project for crystalline rock. The site of the URL project for crystalline rock is located in Mizunami, Gifu, in the central part of the main island of Japan. The regional geology consists of the Tertiary and Quaternary sedimentary rocks overlying Cretaceous granitic basement. Surface-based investigations, including geological mapping, a seismic refraction survey and shallow borehole investigations, and site preparation at the MIU (Mizunami Underground Research Laboratory) Project site have started in 2002. Numerical analysis is carried out to understand mechanical stability around the openings. The ventilation system design is based on numerical analysis using a ventilation network model. Grouting against the high-pressure inflow is planned. Conceptual design for the MIU at present is as follows: • Two 1,000 m shafts, a Main Shaft (6.5m φ) and a Ventilation shaft (4.5m φ); • Two experimental levels, the Main Stage at 1,000 m and the Middle Stage, at 500 m depths. The site of the URL project for sedimentary rock is located in Horonobe, Hokkaido, north of the main island of Japan. The geology consists of Tertiary sedimentary rocks. Surface-based investigation phase started in 2001. Numerical analysis is carried out to understand mechanical stability of the openings, and to design support. The numerical analysis using ventilation network model is carried out to design the ventilation system and disaster prevention method. Conceptual design for the Hnb-URL at present is as follows: • Two 500 m shafts and a Ventilation shaft; • Two experimental levels, the Main Stage at 500 m and the Middle Stage at 250 m depths.

scholarly journals The Influence of the Permeability of the Fractures Zone Around the Heading on the Concentration and Distribution of Methane

2019 ◽  
Vol 12 (1) ◽  
pp. 16 ◽  
Author(s):  
Magdalena Tutak
Keyword(s):  
Ventilation System ◽  
Organizational Factors ◽  
Primary Objective ◽  
Test Results ◽  
Ansys Fluent ◽  
New Approach ◽  
Model Based ◽  
Coal Beds ◽  
Air Stream ◽  
Fluent Software

One of the main problems related to the excavation of dog headings in coal beds is the emission of methane during this process. To prevent the occurrence of dangerous concentration levels of this gas, it is necessary to use an appropriate ventilation system. The operation effectiveness of such a system depends on a number of mining, geological, technical and organizational factors. One of them includes the size and permeability of the fractures zone formed around the excavated dog heading. The primary objective of the paper is to determine the influence of this zone on the ventilation parameters, including the concentration and distribution of methane in the excavated dog heading. In order to achieve the assumed objective, multivariate model-based tests were carried out, which reproduce a real-world dog heading. Literature data and test results in actual conditions were used to determine the size and permeability of the fractures zone around the excavated heading. These data served as the basis to develop a model of the region under analysis and adopt boundary conditions. The analyses were carried out for four permeability values of the fractures zone and for two volumetric flow rates of the air stream supplied to the heading. The results were used to determine the influence of the fractures zone on the distribution and concentration of methane in the heading under analysis. The model-based tests were performed using ANSYS Fluent software. The idea to take into account the fractures zone around the heading represents a new approach to the analysis of ventilation parameters in underground mine headings. The results clearly indicate that this zone affects the ventilation parameters in the heading, including the distribution and concentration of methane. The knowledge obtained from the tests should be used to optimize the ventilation process of dog headings. All authors have read and agreed to the published version of the manuscript.

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