SEL Thermal Card Guide

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Sponsor: Schweitzer Engineering Laboratories
Duration: Fall 2017 - Spring 2018
Team Name Cooler Than Before
Faculty Advisor:
  • Steve Beyerlein
  • Consultants/Mentor:
  • Alex Olson
  • Team Members:
  • Marc Dobson
  • Collin Mabe
  • Nick Tobe
  • Michael Wendell
  • The goal of this project is to develop a card guide design that can be applied in SEL equipment that has a net thermal resistance less than 1 ⁰C/Watt between an aluminum tray (.05"-.1" thick) and the chassis (.05"-.1" thick).  This involves creating an instrumented test stand for measuring heat transfer across the card guide.  Results should be reconciled against an analytical model to assure accuracy.  The recommended solution should meet SEL standards for vibration.

    Problem Definition[edit]

    Deliverables[edit]

    Mathematical heat transfer model Experimental test set-up that can accommodate different guide configurations Experiment design and test results that demonstrate which guide configurations are most effective Comprehensive project documentation for easy future reference by client

    Ctbmodel.jpg
  • This is the current solidworks model of card guide and chassis.
  • Specifications[edit]

    Sepcification Details
    Part Cost Card guide needs to cost less than $5.00/part.
    Dimensions The card guide is to be 5in* long, 0.38in wide, and 0.50in tall. *Possible to design product such that the length is variable.
    Thermal Net thermal resistance of the guide must be ≤1°C/W between the tray it is supporting and the chassis it is fixed to.
    Mechanical Must pass industry standard vibration testing.

    Project Learning[edit]

    Thermal Modeling[edit]

    To determine a suitable card guide our group had to model potential heat transfer rates using solidworks thermal modeling system. Alongside this we are ussing EES to create a math model of the conduction heat transfer of our test setup.

    Ctbthermal.jpg
  • This is the test apparatus designed in solidworks
  • Several heat sources were placed on the end of the guide to create a heat source
  • This model is used to determine the thermal resistance through the card guide
  • Flow Sim[edit]

    File:.jpg

    Test Setup[edit]

    For our test setup we have created a scale version of the thermal card guide.

    Ctbtest.jpg
  • Two power resistors are being used as a heat source for the system
  • The Bell Jar is a vacuum chamber will remove air from the system, thus reducing convection heat transfer.
  • There are several thermocouples placed on the system to measure the gradient across the plate and through the guide.
  • The measurements take from this system can then be extrapolated for different sizes of card guides.
  • The recorded measurements can be used to compare with the SolidWorks and math models
  • Test Data[edit]

    Ctbdata.jpgCtbgraph.jpg

    Test Results[edit]

    After completing a test with the new material and thermocouples, convective heat loss does seem to cause issues when conducting the test in open air. Using the equation: R_t=(T_1-T_2)/q_x =L/kA We were able to calculate resistance values in the model. With temperature values obtained from the test T1 = 54⁰C and T2 = 36⁰C (see image below). The power input to the system was qx = 7.068 W. Measuring the dimensions of the tray and distance between the thermocouples we found A = 82.656x10-6 m2 and L = 0.135 m. Using these values the expected resistance value was Rexpected = 12.098 ⁰C/W. We have concluded that the convection heat loss is not allowing us to acquire correct measurements in open air. Looking at the resistors for our power input, they have fins around the entire housing allowing for greater convective loss resulting in power that isn’t being sent into the tray.

    Guide Design[edit]

    CTB Guide1.png CTB Guide2.png

    Team Information[edit]

    Ctbteam.jpg

    Members[edit]

    Team "CTB"
    Member Biography Discipline
    Marc Dobson

    Team Orginizer

    Bio. Mechanical Engineering
    Collin Mabe

    Treasurer

    Bio. Mechanical Engineering
    Nick Tobe

    Primary Contact

    Bio. Mechanical Engineering
    Michael Wendell

    Secretary

    I am a Senior in Mechanical engineering at the University of Idaho. I plan to graduate and continue my education by getting a masters degree in Business. My interests include working on my motorcycle and playing soccer. Mechanical Engineering