Engineering, 11.02.2020 19:19 Tyrant4life
A common procedure for measuring the velocity of an air stream involves insertion of an electrically heated wire (called a hot-wire anemometer) into the air flow, with the axis of the wire oriented perpendicular to the flow direction. The electrical energy dissipated in the wire is assumed to be transferred to the air by forced convection. Hence, for a prescribed electrical power, the temperature of the wire depends on the convection coefficient, which, in turn, depends on the velocity of the air. Consider a wire of length L=20 mm and dimater D =0.5 mm, for which a calibration of the form, V =6.25 x 10-5- h2, has been determined. The velocity V and the convection coefficient h have units of m/s and W/m2.K, respectively. In an application involving air at a temperature of T? = 25oC, the surface temperature of the anemometer is maintained at Ts =75oC with a voltage drop of 5V and an electrical current of 0.1 A. What is the velocity of the air?
Answers: 1
Engineering, 04.07.2019 18:20
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Answers: 1
Engineering, 04.07.2019 19:20
In the winter, in order to keep the classroom steadily at 68 f before 10 pm, heating with an average rate of 42,000 btu/hr is provided. assume the outdoor temperature maintains at 32°f, determine the electrical power (kw) required to (a) operate a reversible heat pump (b) operate a real heat pump with a cop (7) of 4.5 and (c) operate an electrical-resistance heater.
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Engineering, 04.07.2019 19:20
A5 kg block of fe is dropped into a very large vat of water. the fe and water initial temperatures are 95 and 25 c, respectively. the fe final temperature is 25 c and the water can be treated as a thermal reservoir,. treated as a thermal reservoir take the water to be the system and determine the entropy generation. report vour answer in kj/k.
Answers: 1
A common procedure for measuring the velocity of an air stream involves insertion of an electrically...
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