San Diego State University - Minds That Move the World

Solar Energy

SDSU Masters Theses: Steve Ruther

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Steve Ruther
Master of Science in Mechanical Engineering (Candidate)
Specialization in Thermal Sciences
2008 - 2010 (expected graduation)
B.S.-Chemical Engineering, UC San Diego (2008)


Picture of Steve RutherMy research project is focused on numerical modeling of radiation heat transfer using the Monte Carlo Ray Trace (MCRT) method. This computational technique, when applied to thermal radiation, involves tracing photon bundles along linear trajectories. The MCRT method is different from most numerical methods because it does not approximate the governing equations; instead, the governing equations are interpreted as probability distributions. The direction of a photon bundles trajectory, the wavelength of a photon bundle, if the photon bundle is absorbed or reflected by a surface, the distance a photon bundle will travel before it is absorbed or scattered in a participating medium can all be determined from the probability distributions. The MCRT method is well suited for radiation with a participating medium – as in the case of the small particle solar receiver. The goal of my project is to develop a MCRT program that will simulate the radiation heat transfer from the heliostat field to the flow of small particles in the receiver.

An additional challenge to my project is the incorporation of the flow of the particles through the receiver. The flow plays an important role in the oxidation of the particles and the absorption of the solar flux by the particles. As the particles oxidize their size decreases and they absorb less radiation. The flow of particles will be simulated using the commercial CFD software FLUENT. The MCRT program will be coupled to FLUENT through a source term in the Energy equation, which FLUENT solves in addition to the Navier-Stokes equations.