Optimizing heat transfer performance in two-phase closed thermosyphons: A novel design and experimental evaluation

Area of Science:

• Thermal management
• Heat transfer enhancement
• Phase change heat transfer

Background:

• Effective heat dissipation is critical for electronics, renewable energy, and HVAC systems.
• Two-phase closed thermosyphons (TPCTs) are established for efficient heat transfer.
• Minimizing vapor-liquid interaction is key to improving TPCT performance.

Purpose of the Study:

• To introduce and evaluate a novel TPCT design with an internal cone-shaped tube.
• To assess the impact of this design on thermal performance compared to a conventional TPCT.
• To determine optimal operating parameters (filling ratio, heat input) for different working fluids.

Main Methods:

• Experimental evaluation of a novel TPCT against a conventional design.
• Utilized water and ethanol as working fluids.
• Tested under varying heat inputs (50-250 W) and filling ratios (40-85%).

Main Results:

• Optimal filling ratio is fluid-dependent: 55% & 85% for water, 70% for ethanol.
• Novel TPCT achieved a 45.7% reduction in thermal resistance at 70% filling ratio and 50 W heat input (with ethanol).
• Increased heat input reduced thermal resistance but raised operating temperatures for both designs.

Conclusions:

• The novel TPCT design significantly improves thermal performance over conventional designs.
• The internal cone-shaped tube effectively minimizes vapor-liquid interaction, enhancing heat transfer.
• Performance gains are particularly pronounced with ethanol, highlighting its potential for specific applications.