HEAT TRANSFER ENHANCEMENT OF SURFACES FOR POOL BOILING USING ADDITIVE MANUFACTURING
The continual reduction in sizes of high-powered electronic devices requires more effective heat removal techniques for high heat-flux applications. Nucleate pool boiling has been shown to be an effective method for heat removal under such conditions. Additive manufacturing, also commonly known as 3D-printing, has been identified with the potential to manufacture surfaces with unique geometries for heat transfer enhancement. The Selective Laser Melting (SLM) technique, which employs a fiber-laser to manufacture substrates from powder-based metal in a layer-by-layer basis, was used. The powder used is AlSi10Mg with distribution size range of 20 to 63 μm. Micro-fins of 300 μm diameter and spacing were built on 10 mm by 10 mm substrates for pool boiling studies. A lattice structure made up of Octet-truss unit cells was also fabricated to demonstrate the capability of SLM to create complex and ordered 3D structures. The key advantage of employing SLM is the flexibility to modify surface geometries quickly and to create structures that are deemed difficult to fabricate by conventional machining. Pool boiling experiments were conducted in a water-cooled thermosyphon with dielectric FC-72 as the test fluid. The experimental results show that micro-fin surfaces could only enhance the heat transfer coefficient by about 14% and delayed CHF by more than 35% whereas the lattice structure was able to enhance heat transfer coefficients by about 33%.