Freezing tunnels are no longer inevitable.
In regions with harsh winters, maintaining tunnels free from ice-related damage is a costly and critical challenge. Traditional insulation layers degrade over time and don’t actively stop cold air from entering. But a new study led by Renyuan Wang et al. (2025) introduces an active thermal barrier that uses air curtain jets to transform how we insulate tunnels in cold areas.
What’s New?
The team proposes installing air curtains—jets of warm air—at tunnel portals. These curtains serve a dual purpose:
- Primary: Heat the incoming cold air.
- Secondary: Block or redirect natural wind from entering.
Using a combination of experimental modeling, theoretical equations (including Bessel functions), and finite element simulations, the study shows that these air curtains can:
- Eliminate freezing at tunnel entrances,
- Adapt to changing weather,
- And provide a cost-effective, flexible alternative to traditional insulation.
Key Findings:
- For every 5 °C drop in outside temperature, the tunnel’s frozen zone lengthens by ~77 m.
- Increasing surrounding rock temperature by 5 °C reduces the frozen zone by ~131 m.
- Theoretical predictions closely match simulation results using MATLAB and ANSYS Fluent.
- Even with sudden increases in wind speed, raising the air curtain’s jet temperature can compensate for insufficient speed.
Why It Matters:
- Engineering Insight: Air curtains can be tuned for temperature and velocity—offering precise control.
- Practical Benefit: Compared to foam insulation, air curtains are easier to maintain and modify.
- Wider Use Case: The concept borrows from systems used in museums, fire safety, and HVAC, but now tailored for extreme infrastructure environments.
Bottom Line:
Heating is primary. Blocking is secondary.
This research proves that air curtain thermal insulation isn’t just theoretically sound—it’s ready for real-world deployment in cold-region railways, highways, and mining infrastructure.
Check out the cool NewsWade YouTube video about this article!
Article derived from: Wang, R., Fang, Z., Wang, D., et al. (2025). Theoretical solution research on air curtain thermal insulation technology at tunnel portal in cold area. Scientific Reports, 15, Article 8780. https://doi.org/10.1038/s41598-025-8780
