Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)
8th Edition
ISBN: 9781305387102
Author: Kreith, Frank; Manglik, Raj M.
Publisher: Cengage Learning
expand_more
expand_more
format_list_bulleted
Concept explainers
Question
error_outline
This textbook solution is under construction.
Students have asked these similar questions
The heat conducts through the shape below. The temperature of the right face is 93 °C, while the left face is at 23 °C. If the top and bottom faces are completely insulated, and the thermal conductivity of the material decreases with decreasing temperature.
* Assume that the thermal conductivity is 100 at 23, decreased to 10 at 93.
A) Sketch the temperature profile inside the plate.
B) If both sides of the plate in the above problem is exposed to air: Left side (h = 20 W/m2K, TL = 20 °C) and right side (h = 90 W/m2K). Calculate the temperature of the air on the right side.
15. The wall of a building consists of a 360-mm thick layer A which has a thermal conductivity, kA - 4.9 W/m-K, followed by a 80-mm thick second layer, layer B, which has a thermal conductivity, kg = 0.9 W/m-K. The inside and outside convection coefficients are 20 W/m² K and 39 W/m2 K. At these conditions, what is the overall heat transfer coefficient for this composite wall? Express your answer in W/m^2 K.
Circular fins of uniform cross section, with diameter of 10 mm and length of 50 mm, are attached to a wall with surface temperature of 350°C. The fins are made of material with thermal conductivity of 240 W/m·K, and they are exposed to an ambient air condition of 25°C and the convection heat transfer coefficient is 250 W/m2·K. Determine the heat transfer rate and plot the temperature variation of a single fin for the following boundary conditions: (a) Infinitely long fin (b) Adiabatic fin tip (c) Fin with tip temperature of 250°C (d) Convection from the fin tip
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
- 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.arrow_forward1.4 To measure thermal conductivity, two similar 1-cm-thick specimens are placed in the apparatus shown in the accompanying sketch. Electric current is supplied to the guard heater, and a wattmeter shows that the power dissipation is 10 W. Thermocouples attached to the warmer and to the cooler surfaces show temperatures of 322 and 300 K, respectively. Calculate the thermal conductivity of the material at the mean temperature in W/m K. Problem 1.4arrow_forwardAn electronic device that internally generates 600 mW of heat has a maximum permissible operating temperature of 70C. It is to be cooled in 25C air by attaching aluminum fins with a total surface area of 12cm2. The convection heat transfer coefficient between the fins and the air is 20W/m2K. Estimate the operating temperature when the fins are attached in such a way that (a) there is a contact resistance of approximately 50 K/W between the surface of the device and the fin array and (b) there is no contact resistance (in this case, the construction of the device is more expensive). Comment on the design options.arrow_forward
- 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.arrow_forwardThe heat transfer coefficient for a gas flowing over a thin float plate 3-m long and 0.3-m wide varies with distance from the leading edge according to hc(x)=10x1/4Wm2K If the plate temperature is 170C and the gas temperature is 30C, calculate (a) the average heat transfer coefficient, (b) the rate of heat transfer between the plate and the gas, and (c) the local heat flux 2 m from the leading edge. Problem 1.18arrow_forwardA cold storage room is constructed of an inner layer of 12.7mm of pine, a middle inner of 101.6mm of cork board, and an outer layer of 76.2mm of concrete. The wall surface temperature is 255.4 K inside the cold room and 297.1 k at the outside surface of the concrete. Thermal conductivity of pine is 0.151; corkboard 0.0433; concrete 0.762W/m-K. Calculate the heat loss in W for 1m^2 surface area.arrow_forward
- Steam at a temperature of 723 K is flowing through a pipe with an outer diameter of 100 mm. The pipe is insulated with 30-mm thick mineral wool, the average thermal conductivity of which is 0.065 W/m.K. Determine the outside surface temperature of mineral wool if the ambient air temperature is 300 Assume the hot-surface temperature of the mineral wool is the same as that of the flowing steam and the value of the surface coefficient of the insulating material is 33 W/m2.K.arrow_forwardIn order to reduce the heat loss through a large furnace wall, the decision has been made to add external insulation. Calculate the thickness of insulation required to reduce the heat loss by 75%. Before the change is made, no outer steel shell is used.Data: Refractory brick and wall brick:k = 0.87 W m-1 K-1Insulation: k = 0.090 W m-1 K-1•Steel: k = 43 W m-1 K-1h = 55 W m-1 K-1 (inside furnace).h = 11 W m-1 K-1 (outside furnace).arrow_forwardQuestion 1: A glass window of width W = 1 m and height H = 2 m is 5 mm thick and has a thermal conductivity of kg =1.4 W/m.K. If the inner and outer surface temperatures of the glass are 15 oC and -20 oC, respectively, on a cold winter day, what is the rate of heat loss through the glass? To reduce heat loss through windows, it is customary to use a double pane construction in which adjoining panes are separated by an air space. If the spacing is 10 mm and the glass surfaces in contact with the air have temperatures of 20 oC and -15 oC, what is the rate of heat loss from a 1 m x 2 m window? The thermal conductivity of air is ka = 0.024 W/m.K.arrow_forward
- A 15 mm diameter cylindrical nuclear fuel rod is housed in a hollow ceramic cylinder concentric to the rod with an inner diameter of 35 mm and an outer diameter of 110 mm. This creates an air gap between the fuel rod and the hollow ceramic cylinder with a convective heat transfer coefficient of 10 W/m²·K. The hollow ceramic cylinder has a thermal conductivity of 0.07 W/m·K and its outer surface maintains a constant temperature of 30 °C. If the fuel rod generates heat at a rate of 1 MW/m³. Solving, the temperature at the surface of the fuel rod is 1026°C. I need the solution with fundamental concepts (Textically with definitions) of how the heat flow behaves in the system. NOT THE MATHEMATICAL RESOLUTION. I already know how to solve it.arrow_forwardA 15 mm diameter cylindrical nuclear fuel rod is housed in a hollow ceramic cylinder concentric to the rod with an inner diameter of 35 mm and an outer diameter of 110 mm. This creates an air gap between the fuel rod and the hollow ceramic cylinder with a convective heat transfer coefficient of 10 W/m²·K. The hollow ceramic cylinder has a thermal conductivity of 0.07 W/m·K and its outer surface maintains a constant temperature of 30 °C. If the fuel rod generates heat at a rate of 1 MW/m³. Solving, the temperature at the surface of the fuel rod is 1026°C. Explain how the heat flow behaves in the system, using the fundamental concepts.arrow_forwardA 15 mm diameter cylindrical nuclear fuel rod is housed in a hollow ceramic cylinder concentric to the rod with an inner diameter of 35 mm and an outer diameter of 110 mm. This creates an air gap between the fuel rod and the hollow ceramic cylinder with a convective heat transfer coefficient of 10 W/m²·K. The hollow ceramic cylinder has a thermal conductivity of 0.07 W/m·K and its outer surface maintains a constant temperature of 30 °C. If the fuel rod generates heat at a rate of 1 MW/m³. Solving, the temperature at the surface of the fuel rod is 1026°C. Give the solution from fundamental concepts of how the heat flow behaves in the system.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
- Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning
Principles of Heat Transfer (Activate Learning wi...
Mechanical Engineering
ISBN:9781305387102
Author:Kreith, Frank; Manglik, Raj M.
Publisher:Cengage Learning
Understanding Conduction and the Heat Equation; Author: The Efficient Engineer;https://www.youtube.com/watch?v=6jQsLAqrZGQ;License: Standard youtube license