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Heat Transfer Project

Zirconium Billet Temperature

by Brent Staleyand Brad Smith

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Background

• Zirconium rods are used to house the fuel pellets in nuclear reactors

• Prior to extrusion, the billets must be lubricated to prevent sticking on the die

• The billets must be heated to a specific temperature for the lubricant to cure properly

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Objective

• Heat a Zirconium billet to a desired temperature in a barrel of water and measure the time

• Calculate time needed to achieve desired temperature and compare with measured time

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Calculations

• Assumptions:– Infinite cylindrical shape assumed– Temp. of the barrel wall equals temp. of the

water– Thermal properties are constant throughout

the billet – Spatial effects were considered– Temp. of the water is constant throughout the

barrel

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Calculations

Free Convection of Concentric Cylinder

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Calculations

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Experimental Setup

Popcorn can - hold the water

Pyrometer – measure the surface temperature of billet

Thermometer – measure temperature of the water

Overhead bridge with block of wood – lower the billet into water

Heat plate – heat water to desired temp.

Stop watch – for obvious reasons

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Experimental results

• Temp. water – 180 F• Starting temp. of billet – 78 F• Final temp. of billet – 166 F• Calculated time from 78 F to 166 F – 228

sec• Measured time – 180 sec• Difference of 48 sec

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Conclusions

• The calculated time was 1.27 times longer than the measured time

• We can attribute this discrepancy to: - End effects of the billet - Interference of the pyrometer with water vapor

- 1st order approximate assumption method is just that – an approximation