Award Date

December 2017

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Mechanical Engineering

First Committee Member

Samir F. Moujaes

Second Committee Member

Brendan O'Toole

Third Committee Member

Hui Zhao

Fourth Committee Member

Alexander Barzilov

Fifth Committee Member

Samaan Ladkany

Number of Pages

120

Abstract

The aim of this research is to provide a detailed numerical analysis of flow field and heat transfer inside the heat collecting element of a parabolic trough collector. The parabolic trough collector is used as the boiler in a direct Super Critical Carbon Dioxide (S-CO2) Brayton cycle.

A single collector is modeled and analyzed with different inlet conditions. The working fluid is supercritical since its pressure is increased to above critical pressure in the compressor while its temperature reaches 300 °C after passing through the recuperators and before entering the solar field. For the first time, this research considers both the non-uniform solar radiation irradiance around the trough receiver and the natural convection inside the receiver combined with the nonlinear variations in the physical properties of S-CO2.

Moreover, to investigate the variations in the outputs during a typical day a pseudo steady state scheme is applied. The changes in ambient conditions are so slow compared to the variations in the flow field that in each time step the flow filed is considered to fulfill the

steady state conditions. Hence, steady state numerical analysis is repeated for five time-steps (8 AM, 10 AM, 12 PM, 2 PM and 4 PM) and the results are graphed. A curve is then fitted to the thermal efficiency graph and outlet temperature of receiver graph to let the user interpolate the middle time steps.

Keywords

CFD; numerical analysis; Parabolic trough; solar; Supercritical Carbon dioxide; thermal power plant

Disciplines

Aerodynamics and Fluid Mechanics | Mechanical Engineering | Thermodynamics

Language

English


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