Thermal Turbomachinery Design for Closed Thermal Cycles and Multiple Fluids

Abstract

Closed-cycle gas turbines can complement conventional power conversion systems due to their potential for improved efficiencies, compact system layouts, and the ability to exploit non- newlinefossil fuel energy sources which leads to low carbon emissions. Moreover, they can be adopted for distributed power generation applications. This thesis provides an understanding of the true essence of closed-cycle gas turbines with a focus on the development of turbomachinery design newlinemethodologies. The methodologies have been applied for the radial turbomachinery design newline(small-scale power range) for supercritical Brayton cycles and other thermal cycles such as air cycle, organic Rankine cycle, cryogenic cycles, and steam Rankine cycle. newlineThe thesis begins with an elaborate review of the potential of closed-cycle gas turbines. newlineThermodynamic analysis has been carried out for the recuperated closed Brayton cycle with newlineand without intercooling employing different working fluids. It has shown that the supercritical carbon dioxide gives considerably higher efficiencies at mild turbine inlet temperatures of 400- newline700°C and helium can be considered at higher temperatures of above 800°C. The closed newlineBrayton cycle turbomachinery designs with multiple fluids have been brought together newlineuniquely on two charts, one in absolute scale (and#8710;H-M-D) and other in non-dimensional scale newline(NS-DS) by carrying out a detailed survey of the closed -cycle gas turbine plants and concept designs, which can aid in the design of turbines and compressors for different applications...