Brayton cycle numerical modeling using the RELAP5-3D code, version 4.3.4

Eduardo Pedroso Longhini,Guilherme Borges Ribeiro,Lamartine Nogueira Frutuoso Guimarães,Francisco Antonio Braz Filho,Paulo David De Castro Lobo

doi:10.15392/bjrs.v7i2b.756

Abstract

This work contributes to enable and develop technologies to mount fast microreactors, to generate heat and electric energy, for the purpose to warm and to supply electrically spacecraft equipment and, also, the production of nuclear space propulsion effect. So, for this purpose, the Brayton Cycle demonstrates to be an optimum approach for space nuclear power. The Brayton thermal cycle gas has as characteristic to be a closed cycle, with two adiabatic processes and two isobaric processes. The components performing the cycle's processes are compressor, turbine, heat source, cold source and recuperator. Therefore, the working fluid’s mass flow runs the thermal cycle that converts thermal energy into electrical energy, able to use in spaces and land devices. The objective is numerically to model the Brayton thermal cycle gas on nominal operation with one turbomachine composed for a radial-inflow compressor and turbine of a 40.8 kWe Brayton Rotating Unit (BRU). The Brayton cycle numerical modeling is being performed with the program RELAP5-3D, version 4.3.4. The nominal operation uses as working fluid a mixture 40 g/mole He-Xe with a flow rate of 1.85 kg/s, shaft rotational speed of 45 krpm, compressor and turbine inlet temperature of 400 K and 1149 K, respectively, and compressor exit pressure 0.931 MPa. Then, the aim is to get physical corresponding data to operate each cycle component and the general cycle on this nominal operation.

Highlights

Power systems for space exploration are the establishment of man’s extraterrestrial civilization
Many power systems are being developed to these purposes as solar power systems in which sunlight is converted to electricity by using solar cells made either silicon or gallium arsenide (STINE, 1981) and stored by nickel-cadmiun battery (SNYDER, 1961), chemical power systems using chemical elements as liquid hydrogen, liquid oxygen, hydrazine and others or experimental methods as cryogenically fueled (SNYDER, 1961) and nuclear power systems involving the use of thermal energy liberated by nuclear processes as decay of radioisotopes, controlled fission of heavy nuclei or controlled fusion approach with either thermodynamics cycles – Brayton, Rankine, Stirling cycles - or thermoelectric and thermionic systems for conversion from thermal energy to power energy (ANGELO JR.; BUDEN, 1985)
The nuclear power systems have been studied as the principal power system for future interplanetary exploration missions as Jupiter missions, Mars and Lunar Outposts (BAKER, 2004; GALLO; EL-GENK, 2009; JOYNER II; FOWLER; MATTHEWS, 2003; MASON, 2001; RIBEIRO; BRAZ FILHO; GUIMARÃES, 2015; WRIGHT; FULLER; LIPINSKI, 2005)

Summary

Introduction

Power systems for space exploration are the establishment of man’s extraterrestrial civilization. The nuclear power systems have been studied as the principal power system for future interplanetary exploration missions as Jupiter missions, Mars and Lunar Outposts (BAKER, 2004; GALLO; EL-GENK, 2009; JOYNER II; FOWLER; MATTHEWS, 2003; MASON, 2001; RIBEIRO; BRAZ FILHO; GUIMARÃES, 2015; WRIGHT; FULLER; LIPINSKI, 2005) Their advantages are compact size, low to moderate mass, long operation lifetime, operation in hostile environments, operation independent of the distance from the Sun or of the orientation to the Sun, high system reliability and autonomy (ANGELO JR.; BUDEN, 1985). Among the conversions systems for nuclear power – Brayton cycle, Rankine cycle, Stirling cycle, thermoelectric and thermionic systems -, Brayton cycle in closed type is the most promising energy conversion for space power systems (RIBEIRO; BRAZ FILHO; GUIMARÃES, 2015)

Methods

Results

Conclusion