Post on 13-Jan-2016
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Design for Heat Exchanger of Sensible Heat Transfer of Gas Flows for Pebble Bed Reactor Applications
Jesse SchofieldMasters of Engineering in Mechanical EngineeringApril 2010RPI Hartford
Refresher
• Pebble Bed Modular Reactor (PBMR) Application
• Helium-Helium High Temperature Heat Exchanger (HTHX)
• Turbine stream isolation to prevent possible contamination
• Modular design to allow HTHX series with ability to bypass and replacement without losing cooling ability (Achieve transfer with part of the flow).
Methodology
• Evaluation of Equations and relationships
• Apply Researched design limits (fluid properties, expected Reynolds numbers, transfer coefficients, fouling compensation)
• Preliminary Design Creation• Narrowing and Verification of Successful
Design
Revision of Scope
• Previous goal was for a Optimized Design Method
• Revision will be for single or multiple design/s for specific transfers or property ranges
• Reason: Optimized Design Method requires an extensive iteration process to result in a singular best practice exchanger
• Iteration work is a deep research field using novel genetic algorithms or unique computer software
• Project will represent and analytical test case, rather than an encompassing method for any PBMR application
PBMR Application Limits
System Property RangeReactor Outlet Temp 750-900 CReactor Inlet Temp 280-520 C
Reactor Mass Flowrate 120-320 kg/sReactor Helium Pressure 7-9 Mpa
Turbine Inlet Temp 800-890 CTurbine Outlet Temp 480-500 C
Equations and Standards
• IHX System:• LMTD• NTU-e
• Tubeside:• Seider-Tate Eq• VDI-Mean Nusselt Method
• Shellside:• Bell-Delaware Method• Kern Method• Stream Analysis
Method to Design
Assumptions
• Laminar Flow considerations• Helium-Helium• Simple flow network for fouling
considerations• Material Properties for those deemed
within limits (metal alloys, SiC)• Modular design with 5 IHX for full flow
Remaining Work
• Narrowing of Equation Focus• Establishing Clear calculation
walkthrough• Identification of IHX characteristics• Research on certain properties for
conservative assumptions (fouling rate, appropriate design margin, wall thicknesses for design pressures)
Questions?
• Please see personal webpage for updated references