4. In a manufacturing process, a transparent film is being bonded to a substrate as shown in thesketch. To cure the bond at a temperature To, a radiant source is used to provide a heat flux qo"(W/m²), all of which is absorbed at the bonded surface. The back of the substrate is maintained atT₁ while the free surface of the film is exposed to air at Too and a convection heat transfer coefficienth.AirTo, h=FilmSubstrateL= 0.25 mmk₁ = 0.025 W/m-KL₁ = 1.0 mmBond, To k=0.05 W/m-K(a) Show the thermal circuit representing the steady-state heat transfer situation. Be sure to labelall elements, nodes, and heat rates. Leave in symbolic form.(b) Assume the following conditions: T= 20°C, h =50 W/m²⚫K, and T₁ = 30°C. Calculate the heatflux qo" that is required to maintain the bonded surface at T0= 60°C.(c) Compute and plot the required heat flux as a function of the film thickness for 0≤L+≤1 mm.Answer: (b) 2833W/m²

Step 1:Step 2:Step 3:Step 4:Plot the diagram:

Answered: 4. In a manufacturing process, a…

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter4: Numerical Analysis Of Heat Conduction

Section: Chapter Questions

Problem 4.26P

See similar textbooks

Similar questions

A 0.6-cm diameter mild steel rod at 38C is suddenly immersed in a liquid at 93C with hc=110W/m2K. Determine the time required for the rod to warm to 88C.
A 2.5-cm-OD, 2-cm-ID copper pipe carries liquid oxygen to the storage site of a space shuttle at -183Cand0.04m3/min. The ambient air is at 21C and has a dew point of 10C. How much insulation with a thermal conductivity of 0.02 W/m K is needed to prevent condensation on the exterior of the insulation if hc+h=17W/m2 K on the outside?
One end of a 0.3-m-long steel rod is connected to a wall at 204C. The other end is connected to a wall that is maintained at 93C. Air is blown across the rod so that a heat transfer coefficient of 17W/m2 K is maintained over the entire surface. If the diameter of the rod is 5 cm and the temperature of the air is 38C, what is the net rate of heat loss to the air?
1.51 The inner wall of a rocket motor combustion chamber receives by radiation from a gas at . The convection heat transfer coefficient between the gas and the wall is . If the inner wall of the combustion chamber is at Problem 1.51 a temperature of , determine (a) the total thermal resistance of a unit area of the wall in and (b) the heat flux. Also draw the thermal circuit.
Water at a temperature of 77C is to be evaporated slowly in a vessel. The water is in a low-pressure container surrounded by steam as shown in the sketch below. The steam is condensing at 107C. The overall heat transfer coefficient between the water and the steam is 1100W/m2K. Calculate the surface area of the container that is required to evaporate water at a rate of 0.01 kg/s. Problem 1.16
2.43 A turbine blade 6.3 cm long, with cross-sectional area and perimeter , is made of stainless steel . The temperature of the root, , is . The blade is exposed to a hot gas at , and the heat transfer coefficient is K. Determine the temperature of the blade tip and the rate of heat flow at the root of the blade. Assume that the tip is insulated.
Using Table 1.4 as a guide, prepare a similar table showing the orders of magnitude of the thermal resistances of a unit area for convection between a surface and various fluids.
Determine the power requirement of a soldering iron in which the tip is maintained at 400C. The tip is a cylinder 3 mm in diameter and 10 mm long. The surrounding air temperature is 20C, and the average convection heat transfer coefficient over the tip is 20W/m2K. The tip is highly polished initially, giving it a very low emittance.
3.17 A 1.4-kg aluminum household iron has a 500-W heating element. The surface area is . The ambient temperature is 21°C, and the surface heat transfer coefficient is . How long after the iron is plugged in does its temperature reach 104°C?
The interior wall of a large, commercial walk-in type meat freezer is covered under normal operating conditions with a 2-cm thick layer of ice. One day, a power outage cuts electricity to the refrigeration system of the freezer. Estimate the time required to melt this layer of ice if it has a mass density of 700kg/m3 and a latent heat of fusion of 334 kJ/kg. Consider the air temperature inside the freezer to be 20C with a heat transfer coefficient of 2W/m2K for convection from the freezer surface to air, and clearly state the assumptions made in your calculations.
1.15 A thermocouple (0.8-mm-diameter wire) used to measure the temperature of the quiescent gas in a furnace gives a reading of . It is known, however, that the rate of radiant heat flow per meter length from the hotter furnace walls to the thermocouple wire is 1.1 W/m and the convection heat transfer coefficient between the wire and the gas is K. With this information, estimate the true gas temperature. State your assumptions and indicate the equations used.
1.52 A flat roof of a house absorbs a solar radiation flux of . The backside of the roof is well insulated, while the outside loses heat by radiation and convection to ambient air at . If the emittance of the roof is 0.80 and the convection heat transfer coefficient between the roof and the air is K, calculate (a) the equilibrium surface temperature of the roof and (b) the ratio of convection to radiation heat loss. Can one or the other of these be neglected? Explain your answer.

SEE MORE QUESTIONS

Recommended textbooks for you

Principles of Heat Transfer (Activate Learning wi…

Mechanical Engineering

ISBN:

9781305387102

Author:

Kreith, Frank; Manglik, Raj M.

Publisher:

Cengage Learning