Abstract
A jet fan system for tunnel ventilation switches the impeller's rotational direction to make an airflow in the direction of the traffic flow at the time. It carries dual impellers to equalize the rate of airflow for both the time of ventilating in one direction and in the inverse. We studied a single impeller which would make an equal rate of airflow for both the time of ventilating in one direction and in the inverse. And we found out that it would gain its mass and stress because it would need even longer boom of impeller blade. This is the result of the optimization for the blade cross-section under structure analysis in order to make an impeller with the same strength or higher than the traditional ones.
