jesse schofield masters of engineering in mechanical engineering april 2010 rpi hartford

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