Determine the convection coefficient associated with airflow, Mechanical Engineering

An experiment to determine the convection coefficient associated with airflow over the surface of a thick stainless steel casting involves insertion of thermocouples in the casting at distances of 10 mm and 20 mm from the surface.  When the experiment was performed in a well insulated air duct so that the temperature of the walls surrounding the steel surface was the same as the air temperature, the thermocouples measured the temperatures of 50°C and 40°C in the steel, respectively, when the air and the surrounding wall temperatures were 200oC.

a)      If the steel has a thermal conductivity of 15 W/m2K and surface emissivity of 0.95, what is the convection coefficient between the steel and hot air?

b)      What are the contributions of the convective and radiation heat fluxes to the steel casting?

In the repeated experiments the duct insulation was removed and even though the hot air temperature was the same as before, i.e., 200oC, the surrounding walls temperature dropped to 20oC. As a result the steady state heat flux to the steel casting dropped by 13.3% compared to the first experiment.

c)      Assuming the same convection coefficient as the value calculated in part a), what would be the temperatures measured by the thermocouples?

d)     Suppose that the steel casting were well insulated from all sides except for the surface from which the distance to thermocouples is measured. Assuming the same convection coefficient as the value calculated in part a), what would be the temperatures of the thermocouples when:

i)                    The experiment is performed in the well insulated duct at T = Tsurr = 200oC?

ii)                  The experiment is performed in non-insulated duct at T = 100oC and Tsurr = 20oC?

Posted Date: 7/10/2012 8:12:30 AM | Location : United States







Related Discussions:- Determine the convection coefficient associated with airflow, Assignment Help, Ask Question on Determine the convection coefficient associated with airflow, Get Answer, Expert's Help, Determine the convection coefficient associated with airflow Discussions

Write discussion on Determine the convection coefficient associated with airflow
Your posts are moderated
Related Questions
Determine the Loss of Information During Exchange in IGES Loss of Information During Exchange : Information would inevitably be lost when information is passed between two CAD

An ideal gas is heated at fixed volume until its temperature is 3 times the original temperature. It is then expanded isothermally till it reaches original pressure. The gas is t

Types Of Polymerisation When some of bifunctional molecules connect in a chain structure, the reaction is termed as addition polymerisation.  However, these polymerizations do

Calculate the shear flow in each wall of the fuselage section below. The flange areas are 1 sq in and the web thicknesses are 0.05 in. The material has modulus E = 10 mpsi and G =

(a) Calculate the natural frequency of mass m = 1 Kg placed at one end of a cantilever beam of negligible mass. Length of cantilever = 500 mm, d = 30 mm, b = 20 mm, E = 210x10 9 N

Load on beam: A beam AB as shown in the figure given below is hinged at A and supported at B by a vertical cord that passes over two frictionless pulleys C and

Magnitude of the resultant couple: For non-parallel forces also the location of the line of action of resultant may be determined by utilizing R × d = ∑ M o . The magnitu

#question.needs help to do my assignment.

The Shaft is made of a material with an allowable shear strength of 80 Mpa. a.       Develop the torque diagram b.      Determine the minimum acceptable diameter of the shaft

Compare solid shaft with the hollow: Compare solid shaft with the hollow shaft, by strength and their weight. Sol.: ( a ) Comparison by strength: Assume that both the s