The presented work analyses the design space and performance potential of microfabricated Brayton cycle and Rankine cycle devices, accounting for lower component efficiencies, temperatures limited by the material properties and system implementation constraints imposed by silicon microfabrication and miniaturization. By exploring the design space of such microsystems, their potential thermal ef...

Helium Brayton cycles have been studied as power cycles for both fission and fusion reactors obtaining high thermal efficiency. This paper studies several technological schemes of helium Brayton cycles applied for the HiPER reactor proposal. Since HiPER integrates technologies available at short term, its working conditions results in a very low maximum temperature of the energy sources, someth...

We investigate the optimization of turbo-Brayton cycles for cooling current leads. Simple models of single stage current lead, two-stage current lead and two stage current lead coupled with a double stage turbo-Brayton cycle have been used to provide understanding about the issues and the tradeoffs. In addition, we discuss the possibility of using the heat exchanger in the turbo-Brayton system ...

This paper provides a preliminary analysis of the supercritical Brayton cycle, a power generation system for space exploration. Supercritical working fluids increase efficiency due to increased compressibility at the critical point but have not been investigated at the high temperatures necessary for space power generation. Through computer simulation, the viability of the supercritical Brayton...

in this study, the performance of an irreversible regenerative brayton cycle is sought through power maximizations using finite-time thermodynamic concept in finite-size components. optimizations are performed using a genetic algorithm. in order to take into account the finite-time and finite-size concepts in the current problem, a dimensionless mass-flow rate parameter is used to deploy time v...

conceptual design of a waste heat recovery cycle is carried out in attempt to enhance the thermal efficiency of a steam power plant. in the recovery system, super-critical an co2 is employed as the working fluid operating in a brayton cycle. low grade heat rejected by the flue gases through the stack is used as the primary heat source, while a secondary heat exchanger utilizes the hot gases lea...

Original scientific paper Nondimensional expressions for the work output, thermal efficiency, heat input, and entropy generation number in the Brayton cycle with a recuperator are given as functions of seven input parameters: pressure ratio, temperature ratio, recuperator effectiveness, turbine and compressor isentropic efficiencies, nondimensional pressure drop in the combustor and recuperator...

The He Brayton cycle appears to be the best nearterm power conversion method for maximizing the economic potential of fusion. Key factors affecting the Brayton cycle efficiency includes the turbine inlet temperature, compressor and turbine adiabatic efficiencies, recuperator effectiveness and cycle fractional pressure loss. The compression ratio is also important because for fusion conditions, ...

The combined cycle gas turbine integrates the Brayton cycle as topping cycle and the steam turbine Rankine cycle as bottoming cycle in order to achieve higher thermal efficiency and proper utilization of energy by minimizing the energy loss to a minimum. In this work, the effect of various operating parameters such as maximum temperature and pressure of Rankine cycle, turbine inlet temperature ...

The effect of two heat additions, rather than one, in a gas turbine engine is analyzed from the second law of thermodynamics point of view. A regenerative Brayton cycle model is used for this study, and compared with other models of Brayton cycle. All fluid friction losses in the compressor and turbine are quantified by an isentropic efficiency term. The effect of pressure ratio, turbine inlet ...