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GG(ox/ F*p%F)FF/FFFFFFSOUTH DAKOTA SCHOOL OF MINES AND TECHNOLOGY
DEPARTMENT OF METALLURGICAL ENGINEERING
Met 422 HQ 2 Oct. 29,1987
MI 223 (open book) NOON
1. Find the drag force in dynes for a tethered sphere in a flowing stream of water. The room temperature water is flowing past the 1 cm. diameter sphere at 1000 cm/sec.
2. Estimate the pressure drop required to move 2 liters of water per minute through an ion resin bed with a cross sectional area of 10 cm2. The resin beads are 0.1 cm diameter and have a void fraction of 0.5. The bed is 20 cm deep.
3. What velocity and pressure drop would just fluidize the bed in #2 if the resin density is 1.2 g/cm3?
4. How long would it take to empty a molten steelfilled ladle 3 meters in diameter and 2 meters deep if the tap hole is 5 cm in diameter?
bed with a cross sectional area of 10 cm2.
uMet 422 3Dec. 19402:00 PM1CalculateProblem #1 if the resin density is 1.2 23A long10 cm diameter steel rod initially at 1000 K is subjected to cooling in air at 300 K. The heat transfer coefficient is 2 W/m2/K. How long will it take to reach a temperature of 500 K in the center of the rod?
4If the rod in problem #3 is cut to a length of 10 cm, how long will it take to reach a temperature of 500 K Tjmuv~<=
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at the center of the billet?
room temperature . The bed has 4 andelocity and pressure drop wouldto a void fraction of 0.8? The .All needed physical constants are to be found from the text. Estimations are allowed if needed constants are not contained in the text.
obtainedpermissablea needed constantisavailablepermissiblelong, 10 If was fluidized to , find the
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b) pressure drop across the bed0ere0.8 a timebe requiredrod's a time be required(r=0 and equidistant from each end)
5. An electric heating element for a furnace is connected to the electric power source at each end by watercooled clamps as shown below. The Derive an equation for the axial temperature profile in a rod L in length
DATA: aFE = 0.15 cm2/sec
The rod's temperature is a function of the distance along the axis. There are no significant radial gradients. The electric power generates heat within the element at a rate of S Watts/cm3.
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. Since the temperature profile will be symetrical about the center of the rod's axis, put your coordinate at the rod's center. The rod's length is 2L and its radius is R. heat transfer coefficient is 0.2 c symmetrical
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