Identifier

etd-04112016-160002

Degree

Master of Science (MS)

Department

Mechanical Engineering

Document Type

Thesis

Abstract

In the present work, a complete 3D simulation of ray tracing model is developed for studying the radiation heat transfer, associated with laser based additive manufacturing, in both thick and thin particulate beds by using the Monte Carlo method. Additional program is developed for creating different types of packing structures such as simple cubic, rhombohydral and random packing. The scattering mechanisms in the particulate beds for large opaque spheres are evaluated using the specular and diffuse reflection methods. Further, a novel approach has been added to the model to include isotropic, forward and backward scattering mechanisms for a medium which consists of particles with very small size parameters. Henyey Greenstein phase function is used to evaluate the scattering for extremely small, particulate porous beds. For thick layers, a thorough study has been carried out on the effect of porosity, bed thickness, power inputs and different bed configurations. Whereas for thin layers, the substrate conditions are studied in detail. Then they are analyzed for variation in energy absorbed. The effects of reflective and absorbing boundary conditions are also studied. For the incoming beam both uniform and Gaussian distributions with different angles of incidence has been simulated. The effect of various size parameters on the radiative transport has also been compared for both thick and thin layers. Finally, for thin layers, the model is compared with the two flux method and the unit cell Monte-Carlo method.

Date

2015

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Guo, Shengmin

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