Working in groups of two, our students design and perform

Chapter , Problem 7.4

(choose chapter or problem)

Working in groups of two, our students design and perform experiments on forced convection phenomena using the general arrangement shown schematically. The air box consists of two muffin fans, a plenum chamber, and flow straighteners discharging a nearly uniform airstream over the flat test-plate. The objectives of one experiment were to measure the heat transfer coefficient and to compare the results with standard convection correlations. The velocity of the airstream was measured using a thermistorbased anemometer, and thermocouples were used to determine the temperatures of the airstream and the test-plate. With the airstream from the box fully stabilized at T 20 C, an aluminum plate was preheated in a convection oven and quickly mounted in the testplate holder. The subsequent temperature history of the plate was determined from thermocouple measurements, and histories obtained for airstream velocities of 3 and 9 m/s were fitted by the following polynomial:The temperature T and time t have units of C and s, respectively, and values of the coefficients appropriate for the time interval of the experiments are tabulated as follows: Velocity (m/s) 3 9 Elapsed Time (s) 300 160 a ( C) 56.87 57.00 b ( C/s) 0.1472 0.2641 c ( C/s2 ) 3 104 9 104 d ( C/s3 ) 4 107 2 106 e ( C/s4 ) 2 1010 1 109 The plate is square, 133 mm to a side, with a thickness of 3.2 mm, and is made from a highly polished aluminum alloy ( 2770 kg/m3 , c 875 J/kg K, k 177 W/m K). (a) Determine the heat transfer coefficients for the two cases, assuming the plate behaves as a spacewise isothermal object. (b) Evaluate the coefficients C and m for a correlation of the form Compare this result with a standard flat-plate correlation. Comment on the goodness of the comparison and explain any differences.

Unfortunately, we don't have that question answered yet. But you can get it answered in just 5 hours by Logging in or Becoming a subscriber.

Becoming a subscriber
Or look for another answer

×

Login

Login or Sign up for access to all of our study tools and educational content!

Forgot password?
Register Now

×

Register

Sign up for access to all content on our site!

Or login if you already have an account

×

Reset password

If you have an active account we’ll send you an e-mail for password recovery

Or login if you have your password back