Example The figure below shows the cross section of a wall made of pine of thickness La and brick of thickness Ld (= 2La), sandwiching two layers of unknown material with identical thickness and thermal conductivity. The thermal conductivity of the pine is ka and that of the brick is kd (=5ka). The face area A of the wall is unknown. Thermal conduction through the wall has reached the steady state; the only known interface temperatures are T1 = 25°C, T2 = 20°C, and T5-10°C. What is interface temperature T4? Ti T Indoors ka T3 (a) k₂ 14- (b) ke (c) (d) -T, Outdoors

Example The figure below shows the cross section of a wall made of pine of thickness La and brick of thickness Ld (= 2La), sandwiching two layers of unknown material with identical thickness and thermal conductivity. The thermal conductivity of the pine is ka and that of the brick is kd (=5ka). The face area A of the wall is unknown. Thermal conduction through the wall has reached the steady state; the only known interface temperatures are T1 = 25°C, T2 = 20°C, and T5-10°C. What is interface temperature T4? Ti T Indoors ka T3 (a) k₂ 14- (b) ke (c) (d) -T, Outdoors

College Physics

1st Edition

ISBN:9781938168000

Author:Paul Peter Urone, Roger Hinrichs

Publisher:Paul Peter Urone, Roger Hinrichs

Chapter14: Heat And Heat Transfer Methods

Section: Chapter Questions

Problem 30PE: (a) Calculate the rate of heat conduction through house walls that are 13.0 cm thick and that have...

See similar textbooks

Similar questions

(a) Estimate the specific heat capacity of sodium from the Law of Dulong and Petit. The molar mass of sodium is 23.0 g/mol. (b) What is the percent error of your estimate from the known value, 1230 J/kg ? `
(a) Calculate the rate of heat conduction through house walls that are 13.0 cm thick and that have an average thermal conductivity twice that of glass wool. Assume there are no windows or doors. The surface area of the walls is 120m2 and their inside surface is at 18.0C, while their outside surface is at 5.00C. (b) How many 1-kW room heaters would be needed to balance the heat transfer due to conduction?
You need to precisely measure the dimensions of a large wood panel for construction project. Your metal tape measure was left outside for hours in the sun on a hot summer day. How will your measurements differ from those taken by your coworker, whose tape stayed in the shade. Explain using equations? Assume tape is made of a metal of your choice.
A wire lengthens 4% due to thermal expansion when heated from T. to T. If the wire were bent into the shape of a square, what percent increase in length would you expect along one edge of the square? If the wire were bent into the shape of a circle, what percent increase in diameter would you expect? Explain, using sentences and diagrams.
An incandescent lamp filament, with a surface area of 100 mm2, operates at a temperature of 2300 0 Assume that the filament acts like a blackbody. What is the rate of radiation from the filament? If the walls of the room in which the lamp operates are at 27 0C, what is the rate at which the filament absorbs radiation? At what rate does electrical energy have to supplied tot eh filament to keep its temperature constant? Ignore conduction and convection losses from the filament
I want the calculation for this expiremnt Note: the unit of thermal conductivity w/m.k
Problem 1- Heat Transfer How thick would the glass panes on a double-glazed window (air gap = 2mm) have to be to make the double-glazed resistance to heat transfer equal to the resistance to heat transfer provided by a single pane of glass of thickness 50mm. The thermal conductivity of air and glass are 0.05W/m°C and 0.9W/m°C respectively.
When a metal is heated, its atoms vibrate more about their position in the lattice (a network of crossed bars). This causes them to take up more space, so the solid metal expands from its original shape. Calculate the heat needed to expand a ring made of copper with an internal diameter of 50mm to fit over a shaft of diameter 50.05mm. The shaft is measured at a temperature 20 degrees c
Q4. The following figure shows the specification of a disk, given that disk thickness is 15 mm, and brass thermal conductivity = 123 W/m C. Find the following: Ra - Semm 1- Heat transfer rate. 1-124 C 2- Temperature gradient RI 30mm Tl-17C
The heat equation in 1D is : du = Ở o = constant (a) Given that [t] = T and [x] = L, what is the dimension of o ? Infer a dimensionless variable z A x tª oß.
Learning Goal: To solve for thermal stresses in statically indeterminate bars subject to a temperature change. Most materials change in size when subjected to a temperature change. For a temperature change of a homogenous isotropic material, the change in length of a bar of length I due to a temperature change AT can be calculated as d = aATL, where a is the linear coefficient of thermal expansion-a property of the material the bar is. made from. For a member that is not constrained, this expansion can occur freely. However, if the member is statically indeterminate, the deflection is constrained. Thus, changes in temperature will induce internal thermal stresses. The compatibility condition is that the changes in length due to the temperature change and to the induced stress must cancel each other out, &T + 8 = 0, where NL with N being the induced internal AE SF = normal force, positive for tension. Figure A < 1 of 2 B > Part A Calculate thermal stress The round bar shown…
Given: Calculate the rate of conduction in watts through a 3.00m window that is 0.635cm thick if the temperatures of the inner and outer surfaces are 5.00°C and - 10.0°C, respectively. An average thermal conductivity of glass is 0.84 J/s.m. C. Submit a scanned copy of YOUR detailed and handwritten working in the Drag & Drop box field. Unclear, non-readable files or files sent via email will receive zero. Maximum size for new files. 200, maximum attachments. 2