Answered: Why do we characterize the heat…

Why do we characterize the heat conduction ability of insulators in term of their apparent thermal conductivity instead of the ordinary thermal conductivity?

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 4.12P

See similar textbooks

Related questions

Q: 1/ The roof of an electrically heated home is 6 m long, 8 m wide, and 0.25 m thick, and is made of a…

A: Given data: The area of the roof is A=6×8=48 m2 The thickness of the roof is t=0.25 m The thermal…

Q: Consider a medium in which the heat conduction equation is given in i simplest form as (5) (6) (7)…

A: given:

Q: Calculate the heat transfer rate per unit area of a 200 mm thick concrete wall when the surface…

A: Given :- thickness of concrete wall (L) =200 mm (or) 0.2 m surface…

Q: Determine the temperature variation inside the iron plate with a thickness of 1.5 mm,…

Q: Determine the heat flux for a furnace wall made of fire clay if the furnace wall thickness is 6’’…

A: Given Data⇒ Wall thickness∆t=6'' Since we know that : 1 inch=0.0254 m ∆t=6×0.0254∆t=0.1524 m Thermal…

Q: Calculate the heat transfer rate per unit area of a 200 mm thick concrete wall at a surface…

Q: B. Consider a medium in which the heat conduction equation is given in its simplest form as I OT (-…

Q: Determine the steady-state heat transfer rate per unit area through a # # mm thick homogeneous slab…

A: Fourier's law states that the rate of heat transfer by conduction through the uniform material is…

Q: An experiment is undertaken to determine the thermal conductivity of an unknown material. The…

Q: A 3-mm-diameter and 5-m-long electric wire is tightly wrapped with a 2-mm thick plastic cover whose…

Q: Consider a medium in which the heat conduction equation is given in it simplest form as т т 1 ст a…

A: givenheat conduction equation as shown below

Q: A furnace wall comprises three layers of thickness 250 mm, 100 mm, and 150 mm with thermal…

Q: What is the effect of change in the outer radius of the hollow cylinder on the thermal resistance of…

A: The formula for the thermal resistance of conduction in a hollow cylinder is, Rcond=12πkllnr2r1…

Q: A spherical furnace has an inside diameter of 6ft and an outside diameter of 8ft. The furnace shell…

A: Given data r1 = 3 ft r2 = 4 ft r3 = 4.5 ft r4 = 5 ft Thermal conductivity of inner shell (kA) =…

Q: 1. The wall of a cold room consists of a layer of cork sandwiched between the outer and inner walls…

A: Given: The thickness of each wood walls: →tw=30 mm =0.03 m Inside temperature of the room: →Ti=-20°C…

Q: Required information The upper surface of a 85-cm-thick solid plate (k = 237 W/m-K) is being cooled…

A: Solution:- Given data :- k =237 W/ m.k kfluid = 0.631 W/m.k

Q: In a conduction heat transfer process through a solid slab layer taking place under steady-state…

Q: Overall heat transfer coefficient for the combined mode of heat transfer "Convection Conduction…

A: Draw the diagram of the composite pipe of 2 layers.

Q: A rod of 3 cm diameter and 20 cm length is maintained at 100 °C at one end and 10 °C at the other…

Q: Consider a short cylinder whose top and bottom surfaces are insulated. The cylinder is initially at…

A: Given data: The initial uniform temperature of the cylinder is: Ti. The given temperature of the…

Q: 1- The heat flux through a slab made of wood with 50 mm thick, whose inner and outer surface…

A: Given Thickness of block = 50 mm = 0.05 m Internal temperature = 40 oC External temperature = 20 oC…

Q: Consider a medium in which the heat conduction equation is given in its simplest form as r? ar Or k…

A: 1. Steady 2. 1-D 3. Yes 4. constant

Q: Consider a medium in which the heat conduction equation is given in its simplest form as (a) Is…

Q: Consider a large 5-cm-thick brass plate (k = 111 W/m·°C) in which heat is generated uniformly at a…

Q: Question 1.1: The inner and outer surfaces of a 5-m x 6-m brick wallof thickness 30 cm and thermal…

A: Outer temperature = 20C Inner diameter = 5C Area = 30 m2 Thickness = 30 cm thermal conductivity =…

Q: A1 m-wide by 2 m-high window is composed of two 5 mm-thick glass panes, separated by an air space of…

Q: 058 Btu/h · ft · °R). The inner temperature of the insulation is 67°F. The outer temperature of the…

Q: Determine the steady heat transfer per unit area through a 3.8 cm thick homogeneous slab with its…

A: The solution is as follows

Q: Consider a 40 mmx40 mm x 2 mm thick heat spreader with thermal conductivity of 160 W/m-°C. If the…

A: Given: The dimension of the heat spreader is 40 mm×40 mm×2 mm. The thermal conductivity of heat…

Q: . The wall of a cold room consists of a layer of cork sandwiched between the outer and inner walls…

Q: Heat is to be conducted along a circuit board that has a copper layer on one side. The circuit board…

A: The heat conduction along two-layer board can be expressed as, Heat conduction along an equivalent…

Q: Two identical aluminum plates with thickness of 30 cm are pressed against each other at an average…

A: Given data as per question Thermal conductivity of aluminum = 237 W/m∙K. Heat flux = 7800 w/m2…

Q: What does the assumption of one dimestional heat conduction mean? In the conduction what actual…

A: Assumption of one dimensional heat conduction. Conduction and heat happen at study state condition.…

Q: In determining the thermal conductivity of an insulating material, the temperatures were measured on…

Q: A metallic solid cylinder has a diameter of 11 cm and initial temperature of 300°C. The cylinder is…

A: A metallic solid cylinder has a diameter of 11 cm and an initial temperature of 300o C. The cylinder…

Q: A furnace wall comprises three layers of thickness 250 mm, 100 mm, and 150 mm with thermal…

Q: The handle of a saucepan, 30 cm long and 2 cm in diameter, is subjected to 100 degree Celsius…

A: Data Handle Length (l) = 30 cm = 0.03 mHence some portion of handle…

Question

100%

Why do we characterize the heat conduction ability of insulators in term of their apparent thermal conductivity instead of the ordinary thermal conductivity?

Expert Solution

This question has been solved!

Explore an expertly crafted, step-by-step solution for a thorough understanding of key concepts.

This is a popular solution!

SEE SOLUTION Check out a sample Q&A here

Step 1

VIEW

Step 2

VIEW

Trending now

This is a popular solution!

Step by step

Solved in 2 steps

SEE SOLUTION Check out a sample Q&A here

Knowledge Booster

Learn more about

Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.

Similar questions

1.76 Explain a fundamental characteristic that differentiates conduction from convection and radiation.
1.1 On a cold winter day, the outer surface of a 0.2-m-thick concrete wall of a warehouse is exposed to temperature of –5°C, while the inner surface is kept at 20°C. The thermal conductivity of the concrete is 1.2 W/m K. Determine the heat loss through the wall, which is 10-m long and 3-m high. Problem 1.1
2.38 The addition of aluminum fins has been suggested to increase the rate of heat dissipation from one side of an electronic device 1 m wide and 1 m tall. The fins are to be rectangular in cross section, 2.5 cm long and 0.25 cm thick, as shown in the figure. There are to be 100 fins per meter. The convection heat transfer coefficient, both for the wall and the fins, is estimated to be K. With this information determine the percent increase in the rate of heat transfer of the finned wall compared to the bare wall.
1.19 A cryogenic fluid is stored in a 0.3-m-diameter spherical container is still air. If the convection heat transfer coefficient between the outer surface of the container and the air is 6.8 , the temperature of the air is 27°C, and the temperature of the surface of the sphere is –183°C, determine the rate of heat transfer by convection.
3.16 A large, 2.54-cm.-thick copper plate is placed between two air streams. The heat transfer coefficient on one side is and on the other side is . If the temperature of both streams is suddenly changed from 38°C to 93°C, determine how long it takes for the copper plate to reach a temperature of 82°C.
A high-speed computer is located in a temperature-controlled room at 26C. When the machine is operating, its internal heat generation rate is estimated to be 800 W. The external surface temperature of the computer is to be maintained below 85C. The heat transfer coefficient for the surface of the computer is estimated to be 10W/m2K. What surface area would be necessary to assure safe operation of this machine? Comment on ways to reduce this area.
2.44 To determine the thermal conductivity of a long, solid 2.5-cm-diameter rod, one half of the rod was inserted into a furnace while the other half was projecting into air at . After steady state had been reached, the temperatures at two points 7.6 cm apart were measured and found to be and , respectively. The heat transfer coefficient over the surface of the rod exposed to the air was estimated to be 22.7 . What is thermal conductivity of the rod?
Heat is transferred at a rate of 0.1 kW through glass wool insulation (density=100kg/m3) with a 5-cm thickness and 2-m2 area. If the hot surface is at 70C, determine the temperature of the cooler surface.
1.10 A heat flux meter at the outer (cold) wall of a concrete building indicates that the heat loss through a wall of 10-cm thickness is . If a thermocouple at the inner surface of the wall indicates a temperature of 22°C while another at the outer surface shows 6°C, calculate the thermal conductivity of the concrete and compare your result with the value in Appendix 2, Table 11.
A cooling system is to be designed for a food storage warehouse for keeping perishable foods cool prior to transportation to grocery stores. The warehouse has an effective surface area of 1860 m2 exposed to an ambient air temperature of 32C. The warehouse wall insulation (k=0.17W/(mK)) is 7.5 cm thick. Determine the rate at which heat must be removed (W) from the warehouse to maintain the food at 4C.
Show that the rate of heat conduction per unit length through a long, hollow cylinder of inner radius ri and outer radius ro, made of a material whose thermal conductivity varies linearly with temperature, is given by qkL=TiTo(rori)/kmA where Ti = temperature at the inner surface To = temperature at the outer surface A=2(rori)/ln(ro/ri)km=ko[1+k(Ti+To)/2]L=lenthofcyclinder
1.60 Two electric resistance heaters with a 20 cm length and a 2 cm diameter are inserted into a well-insulated 40-L tank of water that is initially at 300 K. If each heater dissipates 500 W, what is the time required for bringing the water temperature in the tank to 340 K? State your assumption for your analysis.