Enhancement of subcooled pool boiling using 3D printed substrates with microstructures

• Main Author: Zheng, Hanzhou
• Other Authors: Leong Kai Choong
• Format: Final Year Project
• Language: English
• Published: 2015
• Subjects: DRNTU::Science::Physics::Heat and thermodynamics
• Online Access: http://hdl.handle.net/10356/64589
• Institution: Nanyang Technological University

Developments in modern technologies have allowed components of devices to be fabricated with the high compactness and complexity of high thermal dispatching capability. With the growing interest in additive manufacturing technique researches, selective laser melting (SLM) offers the flexibility to modify surface geometries quickly that are deemed difficult to fabricate by conventional machining. This technique employs a method of melting metallic powder layer by layer by a fibre-laser to ensure the bonding of powder in ensuring end product of highly restricted controlled dimension geometry and density. In the project, five similar surfaces of dimensions 10 mm × 10 mm ×1.5 mm have been printed using AlSi10Mg metallic powders of a range of 20 μm to 63 μm distribution sizes by SLM. Saturated pool boiling experiments were performed on these surfaces with HFE 7000 and FC 72 in a thermosyphon system. Microfins featured surfaces ranging 300 μm to 500 μm in fin spacing have been tested in FC 72. The results showed that increment of spacing and size of the square microfins enhances the heat transfer by up to 20% and heat transfer coefficient by at least 10%. For topographically different microcavities and microfins surfaces, heat transfer performance show approximately 40% difference. Different fluid properties affect the heat transfer performance significantly. The outcome varies with surface geometric and topographic changes in, plain, microfins and microcavities surfaces, in FC 72 and HFE 7000. Microcavities surface have shown an improvement of heat transfer approximately of 30% and heat transfer coefficient of nearly 40% in HFE 7000 compared to FC 72.