1. What Are Jet Fans?

Modern underground structures—highway tunnels, metro/rail tunnels, underground car parks—demand rigorous management of air quality, smoke extraction, and passenger safety. Turns out, jet fans have emerged as the standard solution for achieving effective, ductless longitudinal ventilation, designed to handle both routine air circulation and emergency smoke control scenarios.

Jet fans are high-speed axial fans installed in tunnel or underground parking ceilings or walls, generating concentrated airflow that entrains ambient tunnel air, powering ventilation without ducts. They provide compact, modular, and energy-efficient solutions compared with conventional ducted systems.

2. Two Core Jet Fan Types

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2.1 Core Comparison: Unidirectional Jet Fan vs Fully Reversible Jet Fan

2.2 Key Technical Differences‌

1. ‌Thrust Performance‌

   • Unidirectional: Reverse airflow efficiency drops significantly (50%-80% of forward thrust).
   • Fully reversible: Maintains ≥98% rated thrust in both directions via symmetrical aerodynamics.

2. ‌Control Systems‌

   • Fully reversible jet fans integrate reversal modules for sub-30s direction switching (critical for metro tunnel emergencies).

3. ‌Usage Scenarios‌

   • Choose ‌unidirectional jet fan‌ for:
     •    Fixed one-way traffic tunnels
     •    Cost-sensitive projects (e.g., small garages)
   • Opt for ‌fully reversible jet fan‌ when:
     •    Smoke extraction/new air supply must switch rapidly during fires
     •    Railway tunnels require adaptive airflow
     •    Long tunnels use segmented ventilation

3. Conclusion‌

Select unidirectional jet fans for predictable, low-cost ventilation. Specify fully reversible jet fans where emergency response, traffic variability, or regulatory compliance demand agile airflow control.

Note: The data is for reference only, please consult relevant companies for details. And the content of the article cannot avoid omissions and errors. Welcome to propose corrections.