Sharif Digital Repository

Due to growth of the number of passengers in subway transportation systemsthe capacity of the metro stations are on the rise.The generated heat loads in subway line shall be increased by thegrowth of the its capacity. As a result, current subway ventilation systems cannot provide comfort conditions for passengers. Nowadays, modern ventilation systems are designedto improve ventilation performance and to create suitable thermal conditions. Among of these, the under platform andover track exhaust systems and use of platform screen doors can be Cited. The aim of this study is three-dimensional simulation of air flow in modern ventilation systems of subway stations. Numerical simulations are in... 

Gas leak explosion is major risks in closed environment in the chemical industry. One of the fundamental principles of safety is control of ignition sources using special protective equipment in areas where possible flammable gases or vapors are there. Computational fluid dynamics is used in this project to evaluate and analyze the risks associated with gas distribution. Ventilation effect has been studied by computational fluid dynamics on gas cloud formed by leakage of flammable in hazardous areas. To demonstrate the accuracy of calculations performed by computational fluid dynamics, the results are validated by experimental data. The simulated results for gas dispersion are found to be in... 

The purpose of present work is to study the effect of different parameters on the solar chimney used in ventilation. Experimental model and numerical model were used to achieve this goal. First, the model was numerically analyzed by Fluent software using Boussinesq approximation. The results of numerical modeling were validated by the empirical model. Finally, the numerical model can be used to investigate the effects of parameters which modeling is not possible by the empirical model for any reason. Experimental modeling was performed on a chimney with height and width of 180 and 62 cm, respectively. The thickness and angle of chimney in both experimental and numerical methods varied from 5... 

One of the methods of drilling coal mines is mine blasting (drilling with explosives). In this method, explosives such as dynamite are used to excavate the mine and destroy the coal seams. During this type of drilling, in addition to dust, dangerous toxic gases are also produced, so quick and proper ventilation of mine tunnels is necessary in this type of drilling.Depending on the type of mining, the required ventilation system may be different. For example, if the drilling method is long-term method, the mine ventilation is of the U type, but if the mine drilling is the sub-level caving type, auxiliary ventilation is used.In this study, the method of mining is sub-level caving, so that one...