الفهرس 
Organic Rankine Cycle
Radial Inflow Turbine and Computational MethodsOnly 14 pages are availabe for public view
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Abstract
In order to satisfy global energy demands and in the meanwhile limiting greenhouse gases emitting from conventional power systems, both renewable energy and energy efficiency should be introduced into power generation systems. It is thus crucial to introduce non-conventional technologies to recover low grade heat sources and harness renewable energy sources. Organic Rankine Cycle (ORC) is one of these technologies that have been recently used as low-grade heat recovery system.
This thesis presents a numerical study that leads to the proper selection of a working fluid for use in low-temperature ORC turbo-expander. This selection was not only based on the provision of best efficiency but also to comply with global warming potential (GWP) regulations. For that purpose, six pure organic working fluids, R245fa, R236fa, R123, R600a, R134a, and R1234yf as well as zeotropic mixture of R245fa/R600a, were examined. The investigation was basically conducted on a single stage radial inflow turbine, which was originally used in the Sundstrand Power Systems T-100 Multipurpose Small Power Unit. In addition, different numbers of both nozzle and rotor blades of the radial inflow turbine were examined. The commercial package ANSYS-CFX 16.0 was used to perform the numerical study using 3D Reynolds-Averaged Navier–Stokes (RANS) approach. Peng–Robinson equation of state was adopted in the solver to determine the real-gas properties.
The obtained results showed that the performance of ORC turbo-expander was highly influenced by both the selection of the working fluid and cycle operational conditions.