Design of a longitudinal ventilation system for a long tunnel ventilated by jet fans

A collocated finite volume code was developed to simulate the air flow in a tunnel ventilated by jet fans attached to the ceiling. The performance of the code was validated by simulating the cavity test case and quantitatively comparing the resulted data with available experimental data. The simulations were performed for different jet outlet angles to obtain an optimum angle which engenders the most efficient ventilation in tunnel. The same procedure was performed to obtain an optimum jet outlet velocity as well as the distance between jet motors and tunnel’s ceiling. Moreover the airflow produced by a single fan was compared with air flow caused by double fans positioned in different distances from each other to question the justification of using two fans in ventilation system and to obtain an optimum distance between fans. Concerning the fact that the main purpose of ventilation in tunnel is to produce air flow near the floor, a new variable, average flow height, was introduced and calculated in each case to carry out a more accurate and useful comparison between different design features

کلیدواژه ها:

jet fans ، longitudinal ventilation ، mass transport ، CFD