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Title: Scaling of Thermal-Hydraulic Experiments for a Space Rankine Cycle and Selection of a Preconceptual Scaled Experiment Design

Abstract

To assist with the development of a space-based Rankine cycle power system using liquid potassium as the working fluid, a study has been conducted on possible scaled experiments with simulant fluids. This report will consider several possible working fluids and describe a scaling methodology to achieve thermal-hydraulic similarity between an actual potassium system and scaled representations of the Rankine cycle boiler or condenser. The most practical scaling approach examined is based on the selection of perfluorohexane (FC-72) as the simulant. Using the scaling methodology, a series of possible solutions have been calculated for the FC-72 boiler and condenser. The possible scaled systems will then be compared and preconceptual specifications and drawings given for the most promising design. The preconceptual design concept will also include integrating the scaled boiler and scaled condenser into a single experimental loop. All the preconceptual system specifications appear practical from a fabrication and experimental standpoint, but further work will be needed to arrive at a final experiment design.

Authors:
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
885976
Report Number(s):
ORNL/TM-2005/213
TRN: US200617%%283
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; BOILERS; DESIGN; FABRICATION; POTASSIUM; RANKINE CYCLE; RANKINE CYCLE POWER SYSTEMS; SPECIFICATIONS; WORKING FLUIDS

Citation Formats

Sulfredge, CD. Scaling of Thermal-Hydraulic Experiments for a Space Rankine Cycle and Selection of a Preconceptual Scaled Experiment Design. United States: N. p., 2006. Web. doi:10.2172/885976.
Sulfredge, CD. Scaling of Thermal-Hydraulic Experiments for a Space Rankine Cycle and Selection of a Preconceptual Scaled Experiment Design. United States. doi:10.2172/885976.
Sulfredge, CD. Fri . "Scaling of Thermal-Hydraulic Experiments for a Space Rankine Cycle and Selection of a Preconceptual Scaled Experiment Design". United States. doi:10.2172/885976. https://www.osti.gov/servlets/purl/885976.
@article{osti_885976,
title = {Scaling of Thermal-Hydraulic Experiments for a Space Rankine Cycle and Selection of a Preconceptual Scaled Experiment Design},
author = {Sulfredge, CD},
abstractNote = {To assist with the development of a space-based Rankine cycle power system using liquid potassium as the working fluid, a study has been conducted on possible scaled experiments with simulant fluids. This report will consider several possible working fluids and describe a scaling methodology to achieve thermal-hydraulic similarity between an actual potassium system and scaled representations of the Rankine cycle boiler or condenser. The most practical scaling approach examined is based on the selection of perfluorohexane (FC-72) as the simulant. Using the scaling methodology, a series of possible solutions have been calculated for the FC-72 boiler and condenser. The possible scaled systems will then be compared and preconceptual specifications and drawings given for the most promising design. The preconceptual design concept will also include integrating the scaled boiler and scaled condenser into a single experimental loop. All the preconceptual system specifications appear practical from a fabrication and experimental standpoint, but further work will be needed to arrive at a final experiment design.},
doi = {10.2172/885976},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Jan 27 00:00:00 EST 2006},
month = {Fri Jan 27 00:00:00 EST 2006}
}

Technical Report:

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  • Experiments investigating a sieve-tray direct-contact heat exchanger were conducted at the Raft River Geothermal Test Site in southeastern Idaho using the 60-kW Mobile Heat Cycle Research Facility operating in the thermal loop mode (without a turbine). Isobutane, propane, and several hydrocarbon mixtures were heated and boiled in the direct-contact column, which is approx. 12 in. in diameter and 19-1/2 ft. high, using the energy from a 280/sup 0/F geothermal resource. Using pure fluids, isobutane or propane, the column operated much as intended, with 17 trays used for preheating and one or two accomplishing the boiling. For the pure fluids, individualmore » tray efficiencies were found to be 70% or higher for preheating, and close to 100% for boiling; column pinch points were projected to be well under 1/sup 0/F with some runs reaching values as low as approx. 0.02/sup 0/F. Maximum geofluid throughputs for the isobutane tests corresponded roughly to the terminal rise velocity of a 1/32 in. working fluid droplet in geofluid. Boiling was found to occur in as many as 12 trays for the mixtures having the highest concentrations of the minor component, with overall efficiencies in the boiling section estimated on the order of 25 or 30%. Preheating tray efficiencies appeared to be fairly independent of working fluid, with pinch points ranging from as low as approx. 0.03/sup 0/F for a 0.95 isobutane/0.05 hexane mixture to approx. 2.3/sup 0/F for a 0.85 isobutane/0.05 hexane mixture. Column operation was noticeably less stable for the mixtures than for the pure fluids, with maximum throughputs dropping to as low as 40 to 50% of those for the pure fluids.« less
  • An organic Rankine-cycle (ORC) power module was designed and developed for use in a multi-module solar power plant to be built and operated in a small community. Although neither final design nor construction of the multi-module plant took place, many successful components and subsystems, including the receiver, power conversion subsystem, energy transport subsystem, and control subsystem, were developed and tested before the program was halted. In addition, tests were performed on a complete power module using a test bed concentrator in place of the proposed concentrator at the Jet Propulsion Laboratory's Parabolic Dish Test Site at Edwards Air Force Base,more » California. Test results with the complete module verified that all major single-module program functional objectives were met and that multi-module operation presented no apparent problems. The hermetically sealed, self-contained, ORC power conversion unit subsequently successfully completed a 300-h endurance run with no evidence of wear or operating problems.« less
  • A theoretical design was performed for the condenser/boiler of a space-based solar-dynamic power system. The base system is a binary Rankine cycle with mercury and toluene, as the working fluids. System output is 75 KWe with a combined efficiency of 41.1%. Design goals were to develop the most-reliable, mass-efficient unit possible for delivery to a space station. The design sized the unit based on toluene properties and used a computer generated heat balance to thermodynamically match the two fluids. Molybdenum was chosen as the material due to mass effectiveness in heat transfer, strength, and resistance to mercury corrosion. The unitmore » transfers 137.46 kilowatts of thermal power and can operate at varying mass-flow rates. Effectiveness in heat transfer is 0.96 and mass performance is 0.016 kg/KWth transferred. The design keyed on using only existing technologies, and the results call for no new developments.« less
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