The Frigid Fabric in Falling Flurries Phenomenon - PowerPoint PPT Presentation

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The Frigid Fabric in Falling Flurries Phenomenon

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ME 340 Heat Transfer. Fall 2006. Dr. Vladimir Petrovich Solovjov. The Problem. The cold walk up to campus in the winter. Wind chilling to the bone. ... – PowerPoint PPT presentation

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Title: The Frigid Fabric in Falling Flurries Phenomenon


1
The Frigid Fabric in Falling Flurries Phenomenon
By Drew Hosford and Brianne Hamilton ME 340 Heat
Transfer Fall 2006 Dr. Vladimir Petrovich
Solovjov
2
The Problem
  • The cold walk up to campus in the winter.
  • Wind chilling to the bone.
  • Which material is the best to keep a student
    warm?

3
Assumptions
  • The torso can be approximated as a cylinder.
  • People only wear one layer of clothing under
    their coat.
  • Coats are of uniform thickness in order to better
    compare their thermal properties.
  • The draft between the shirt and the coat is one
    tenth the outside wind velocity.
  • The coat is dry.
  • There is constant flux through the layers.

4
Schematic of Problem Setup
5
Equations
6
Results Wind Speed
Cotton k 0.03 Cotton k 0.03 Cotton k 0.03
Wind speed (m/s) Wind speed (MPH) qdot (W/m3)
0.5 1.118468146 158503
0.6 1.342161775 167126
0.7 1.565855404 173829
0.8 1.789549034 179231
0.9 2.013242663 183765
1 2.236936292 187483
1.25 2.796170365 194850
1.5 3.355404438 200272
1.75 3.914638511 204472
2 4.473872584 207846
3 6.710808876 216729
4 8.947745168 221937
5 11.18468146 225432
10 22.36936292 233759
7
Results Fabric
wool/felt Cotton/Poly Cotton Acrylic PTFE
Wind speed 0.5 m/s k 0.04 k 0.029 k0.03 k 0.2 k 0.25
qdot (W/m3) 223666 149514 158503 379959 387769
8
Conclusions
  • Wind speed has a logarithmic effect on the amount
    of heat generation necessary to maintain
    homeostasis
  • The most effective coat in these conditions would
    be the Cotton/Polyester coat

9
Excel Spreadsheet (Double Click)
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