The heat flux that is applied to the left face of a plane wall is q" = 50 W/m². The wall is of thickness L = 12 mm and of thermal conductivity k = 12 W/m-K. If the surface temperatures of the wall are measured to be 50°C on the left side and 30°C on the right side, then steady-state conditions have been reached. then steady-state conditions have not been reached.

The heat flux that is applied to the left face of a plane wall is q" = 50 W/m². The wall is of thickness L = 12 mm and of thermal conductivity k = 12 W/m-K. If the surface temperatures of the wall are measured to be 50°C on the left side and 30°C on the right side, then steady-state conditions have been reached. then steady-state conditions have not been reached.

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.

Chapter1: Basic Modes Of Heat Transfer

Section: Chapter Questions

Problem 1.10P: 1.10 A heat flux meter at the outer (cold) wall of a concrete building indicates that the heat loss...

See similar textbooks

Similar questions

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.
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.
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.
Estimate the rate of heat loss per unit length from a 5-cm ID, 6-cm OD steel pipe covered with high-temperature insulation having a thermal conductivity of 0.11 W/(m K) and a thickness of 1.2 cm. Steam flows in the pipe. It has a quality of 99% and is at 150C. The unit thermal resistance at the inner wall is 0.0026(m2K)/W the heat transfer coefficient at the outer surface is 17W/(m2K) and the ambient temperature is 16C.
Problems within the wall is T(x) = a(L- ) +b where a = 10°C/m2 and b 30°C, what is the thermal con- ductivity of the wall? What is the value of the convec- tion heat transfer coefficient, h? 2.11 Consider steady-state conditions for one-dimensional conduction in a plane wall having a thermal conductiv- ity k 50 W/m K and a thickness L = 0.25 m, with no internal heat generation. 2. T2 T1 L Determine the heat flux and the unknown quantity for each case and sketch the temperature distribution, indi- cating the direction of the heat flux. 2 Case TC) dTldx (K/m) T2(°C) 1 50 -20 2 -30 - 10 3 70 160 4 40 -80 5 30 200
Consider a 40 mmx40 mmx 2 mm thick heat spreader with thermal conductivity of 160 W/m-°C. If the temperature difference across its thickness is 2°C, what is the heat transfer rate through it?
A 90-amp electric current is flowing through a 6-mm diameter lead wire. The thermal conductivity of the lead is k= 32 W/m K and the electrical resistance per unit length of the wire is R' = 0.0073 /m. The outer surface of the lead wire is exposed to 40°C air with a convection heat transfer coefficient of h=12 W/m².K. Find the temperature at the center of the lead wire.
(1) The temperature of inner surface of insulation wall is t,=100°C, while the outer surface releases the heat by convection to surroundings air with temperature of -20°C. The thickness of the insulating layer is 5 cm and its thermal conductivity of 0,05 W/(m-K). What is the value of heat transfer coefficient on the outside this wall if its surface temperature t, is of 0°C.
Consider a large plane wali of thickness L03 m thermal conductivity k25 /m K, end surfece aree A 12 m The left side of the well ot x=O is subjected to a net heat flux of go760 W/m while the temperature at that surfece is measured to be T 80°C Assuming constant thermal conductivity and no heat generation in the wall, ovaluate the temperature of the right surface of the wall at xEL The temperature of the right surfaoe of the wall at x Lis
200 W/m K, but the thermal conductivity of Rod 2, 3-130 Two very long, slender rods of the same diameter and length are given. One rod (Rod 1) is made of aluminum and has a thermal conductivity k k2, is not known. To determine the thermal conductivity of Rod 2, both rods at one end are thermally attached to a metal surface which is maintained at a constant temperature Th Both rods are losing heat by convection, with a convection heat transfer coefficient h into the ambient air at Teg. The surface temperature of each rod is measured at various distances from the hot base surface. The measurements = 40 cm from the base is the same as that of the rod of unknown thermal conductivity (Rod 2) at x2 = 20 cm from the base. Determine the reveal that the temperature of the aluminum rod (Rod 1) at X thermal conductivity k2 of the second rod (W/m K) FIGURE P3-130 k=200 W/m K Rod 1 1= 40 cm т, Tа) h, T Rod 2 2= 20 cm T2(x
The wall of a house is 7m wide and 6m high and is made from 0.3 m thick brick with a coefficient of thermal conductivity k = 0.6 W/m-K. The surface temperature inside the house is 6°C and that on the outside is 18°C. Find the amount of heat flow on the wall.
An aluminum tube is 200 cm long and has a outside diameter of 2 cm and wall thickness of 5 mm. One end is kept at a constant temperature of 300°C and the other is kept at a temperature or 10 °C. Assume the tube sides are adiabatic. Calculate the heat transfer through the tube. Use finite difference analysis to calculate the temperature very 10 cms.