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Unformatted text preview: ME 322 PS #3 30 April / 1 May 2008 1. The proposed design for an anemometer to determine the velocity of an airstream in a wind tunnel is comprised of a thin metallic strip whose ends are supported by stiff rods serving as electrodes for passage of current used to heat the strip. A fine-wire thermocouple is attached to the trailing edge of the strip and serves as the sensor for a system that controls the power to maintain the strip at a constant operating temperature for variable airstream velocities. Design conditions pertain to an airstream at 25ºC and 1 atm, whose velocity is between 1 and 50 m/s, with a strip temperature of 35ºC. Determine the relationship between the electrical power dissipation per unit width of the strip in the transverse direction, P’ (W/m), and the airstream velocity. (Note that two sides of the metallic strip are exposed to the air stream.) 2. Beverage in cans 150 mm long and 60 mm in diameter is initially 27ºC and is to be cooled by placement in a refrigerator compartment at 4ºC. In the interest of maximizing the cooling rate, should the cans be in a refrigerator compartment at 4ºC....
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- Spring '11
- Heat Transfer