Fluid flow and heat transfer performance for micro-lattice structures fabricated by Selective Laser Melting

Lattice structures are promising candidates for multifunctional thermal protection systems. This study investigated the manufacturability, fluid flow and heat transfer performance of typical micro-lattices fabricated by Selective Laser Melting process. The additively manufactured structures included Kagome lattice, Body Centered Cubic (BCC) lattice, Face Centered Cubic (FCC) lattice, X-type lattice and pin fin. The printing deviation of the lattice structures was assessed by means of CT and optical profilometer. Meanwhile, the thermal performance as well as flow mechanism of the printed lattices were investigated through steady state heat transfer experiments and numerical simulations. The CT scan results showed that the printed lattice structures had acceptable dimensional accuracy. However, the results from optical profilometer indicated that the printed structures had relatively rough surface, and the average roughness of the inner channel surface was about twice that of the outer channel surface. The heat transfer experimental results indicated that, for a given porosity, the X-type lattice provided the best heat transfer enhancement among these structures, and the pin fin had obvious advantages in reducing pressure drop. In terms of overall thermal efficiency, the BCC lattice, the Kagome lattice and the X-type lattice are promising alternatives to conventional pin fins for turbine blade internal cooling, while the FCC lattice is not a good choice. In addition, numerical simulation indicated that the degree of heat transfer enhancement was closely related to the scale of the vortex generated in the flow field.

Automated summary

Selective Laser Melting (SLM) fabricated micro-lattices showed acceptable dimensional accuracy but relatively rough surface. Among the structures, X-type lattice exhibited the best heat transfer enhancement, while pin fin had advantages in reducing pressure drop. Numerical simulation suggested that the heat transfer enhancement was closely related to the scale of vortex generated in the flow field.