Estimate the tempreture measured by thermocouples, 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: 3/19/2013 1:32:24 AM | Location : United States







Related Discussions:- Estimate the tempreture measured by thermocouples, Assignment Help, Ask Question on Estimate the tempreture measured by thermocouples, Get Answer, Expert's Help, Estimate the tempreture measured by thermocouples Discussions

Write discussion on Estimate the tempreture measured by thermocouples
Your posts are moderated
Related Questions
For the beam shown below, we need to determine: (i)  the support reactions R L and R R (ii) the shear force and bending moment diagrams (iii) the maximum stress in the b

Importance of operation research in decision making


This section shall apply to the general requirements for design, fabrication, erection, and testing of structural steels for supports, stairways, ladders and platforms. All stru

How are footings described and introduced properly? The selection of different types of footings and the need for reinforcing the same are discussed in this unit. Methods of de

Q. Design Safe Areas for plant? A Safe Area in this manual is regarded as a space that is not ranked as being a designated hazardous area by the relevant Regional or Country st

As shown in the figure, the jet transport B is flying north with a velocity vB = 600 km/h when a smaller aircraft A passes underneath the transport headed in the 60 degree directio

Q. Explain about Fired Heaters and Combustion Engines? Fired heaters and combustion engines shall normally be located at a safe distance from hazardous areas as they provide po

A hydraulic pipe is 20 cm internal diameter and 5 cm thick. It is needed to sustain an intensities of radial and hoop stress at several radii and plot their variation.

What are the Special Considerations in Planning The dimensions of the foundation should be such that for low-speed machines (operating speed less than 500  rpm) the natural fre