L LL KL KLM G Bimetallic Finned Tubes For Heat Exchangers
🌡️ Design and Application of Bimetallic Finned Tubes in Heat Exchangers
Bimetallic finned tubes optimize heat exchanger efficiency, corrosion resistance, and mechanical strength through strategic material combinations. Key structural designs, material configurations, and performance advantages are summarized below based on industrial practice:
🔧 1. Core Structural Design
- Dual-Layer Tube & Fin Integration:
- Inner tube (copper/aluminum) provides high thermal conductivity; outer tube/fins use corrosion-resistant alloys (e.g., stainless steel), forming a mechanical interlock to minimize interfacial thermal resistance.
- Fins extend from the inner tube’s outer surface to the outer tube’s inner surface, creating multi-channel flow paths to enhance turbulence and heat transfer area.
- Fin Layout Optimization:
- Radially arranged winglets (e.g., 12 winglets at 50°–110° attack angles) reduce wake zones and improve local impingement heat transfer.
⚙️ 2. Material Combinations & Customization
| Component | Typical Materials | Functional Advantage |
|---|---|---|
| Inner Tube/Fins | Copper, Al 1060, Ni alloy (N04400) | High thermal conductivity |
| Outer Tube/Housing | SS 304/316L, N08825 alloy | Corrosion/HP resistance for acid/sulfur environments |
Custom Example: GMP-certified double-tube heat exchangers with SS304 inner core + 316L housing support curved arrangements for compact spaces.
⚡ 3. Performance Enhancement Technologies
- Passive Heat Transfer Enhancement:
- Circular fin inserts in double-pipe structures combined with nanofluids (e.g., TiO₂/CuO) increase thermal conductivity by 20–30% while reducing flow resistance.
- Flow Path & Baffle Innovations:
- Double-pass shell-and-tube designs with angled-elliptical tube bundles reduce Δp and improve energy efficiency coefficient (EEC) by 10.7–20.9%.
🏭 4. Industrial Applications
- Petrochemical & Power: Hydrotreater air coolers with N04400 inner tubes + SS housing withstand H₂S corrosion and high pressure (≤2.5MPa).
- Food & Pharma: Copper-SS bimetallic tubes for antimicrobial properties and autoclave compatibility in GMP systems.
- Compact Systems: Marine/vehicular heat exchangers use low-fin heights (≤16.5mm) and winglet designs to balance space constraints and thermal demands.
💎 Technical Advantages Summary
Bimetallic finned tubes achieve >40% thermal resistance reduction through optimized interfaces (mechanical interlocks/coatings), while offering corrosion protection and vibration resistance. Service life reaches 8–15 years in corrosive media or frequent thermal cycling environments.