Explain the role of fans and ducts in tunnel ventilation, and how they facilitate airflow control.

Fans and ducts play a crucial role in tunnel ventilation systems, facilitating airflow control to maintain air quality, control smoke during emergencies, and ensure a safe environment for tunnel users and personnel. Let's explore their roles in detail: 1. Fans in Tunnel Ventilation: * Purpose: Fans are the primary components responsible for inducing and controlling the airflow within the tunnel. They create a pressure difference, driving air from one end of the tunnel to the other, and extract polluted or smoke-filled air from the tunnel interior. * Airflow Control: Fans are equipped with variable speed drives or multiple fan units to adjust the airflow rates based on changing conditions, such as traffic volume, vehicle emissions, and weather conditions. * Smoke Management: In case of a fire incident, smoke management is crucial to maintain visibility and facilitate safe evacuation. Fans play a vital role in extracting smoke from the tunnel and directing it to designated smoke extraction points. 2. Ducts in Tunnel Ventilation: * Conveying Airflow: Ducts are enclosed channels that guide and distribute airflow from the fans to different sections of....