Lab 5 Hot Dog Anemometer Prof Isntructions

# Lab 5 Hot Dog Anemometer Prof Isntructions - Lab 5 Air...

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Lab 5 Air Velocity Determination Using a Hot Dog Anemometer Overview Did you know that you can determine air velocity using a thermocouple and a hot dog? Using the Heisler charts and correlations for flow over a cylinder, you can back out air velocity if you know how the center temperature of an initially warm hot dog changes with time; thus, you have created a “hot dog anemometer (HDA)”. In this lab we will substitute a plastic cylinder for the hot dog since its properties are better known (and it’s easier to insert the thermocouple right in the middle). An estimate of the heat transfer coefficient will be made using the Heisler charts or corresponding equations. The expected air velocity that results in that value of h will be calculated using a standard Nusselt number correlation for a cylinder in cross flow. This velocity will be compared to the value calculated using an orifice plate to determine the accuracy of our anemometer. During this lab, divide into three groups to perform the three tasks below. They do not need to be completed in order – the teams will rotate. Work in groups of two or three on each task. Task 1 Read the entire procedure before starting this task. Procedure Fill the electric kettle almost to the “max” line. Put the top back on, and turn on the kettle. If the top has been put back on, the kettle will automatically turn off when the water starts to boil. After the water starts to boil, carefully pour it into the orange insulated cup, almost to the top. Put the cylinder in the water. The water should go almost to the top of the cylinder. A T-type thermocouple is embedded in the center of the cylinder. Thermally conductive epoxy surrounds the thermocouple, ensuring that the thermocouple temperature is close to the actually cylinder center temperature. Monitor the thermocouple temperatures (Make sure that the reader is set up for T-type thermocouples. It should have a little “T” up top on the screen.). You should not remove the cylinder until its center temperature stops increasing (probably around 80ºC). During this time, zero the manometer used with the orifice

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## This note was uploaded on 09/08/2010 for the course ME 115 at San Jose State.

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Lab 5 Hot Dog Anemometer Prof Isntructions - Lab 5 Air...

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