Steady state temperatures at three nodes are given in K. This object generates heat itself at rate of q = 5×107 W/m³ and has a thermal conductivity of 20 W/m K. Two of its sides are maintained at a constant temperature of 300 K, while the others are insulated. Find temperatures at nodes 1, 2 and 3 in K. 5 mm 2 398.0 348.5 3 374.6 - Uniform temperature, 300 K 5 mm

Steady state temperatures at three nodes are given in K. This object generates heat itself at rate of q = 5×107 W/m³ and has a thermal conductivity of 20 W/m K. Two of its sides are maintained at a constant temperature of 300 K, while the others are insulated. Find temperatures at nodes 1, 2 and 3 in K. 5 mm 2 398.0 348.5 3 374.6 - Uniform temperature, 300 K 5 mm

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.

Chapter2: Steady Heat Conduction

Section: Chapter Questions

Problem 2.15P: 2.15 Suppose that a pipe carrying a hot fluid with an external temperature of and outer radius is...

See similar textbooks

Similar questions

To determine the thermal conductivity of a structural material, a large 15-cm-thick slab of the material is subjected to a uniform heat flux of 2500 W/m2 while thermocouples embedded in the wall at 2.5 cm. intervals are read over a period of time. After the system had reached equilibrium, an operator recorded the thermocouple readings shown below for two different environmental conditions: Distance from the Surface (cm) Temperature (C) Test 1 0 40 5 65 10 97 15 132 Test 2 0 95 5 130 10 168 15 208 From these data, determine an approximate expression for the thermal conductivity as a function of temperature between 40 and 208C.
A plane wall, 7.5 cm thick, generates heat internally at the rate of 105 W/m3. One side of the wall is insulated, and the other side is exposed to an environment at 90C. The convection heat transfer coefficient between the wall and the environment is 500 W/m2 K. If the thermal conductivity of the wall is 12 W/m K, calculate the maximum temperature in the wall.
2.15 Suppose that a pipe carrying a hot fluid with an external temperature of and outer radius is to be insulated with an insulation material of thermal conductivity k and outer radius . Show that if the convection heat transfer coefficient on the outside of the insulation is and the environmental temperature is , the addition of insulation actually increases the rate of heat loss if , and the maximum heat loss occurs when . This radius, is often called the critical radius.
2.2 A small dam, which is idealized by a large slab 1.2 m thick, is to be completely poured in a short Period of time. The hydration of the concrete results in the equivalent of a distributed source of constant strength of 100 W/m3. If both dam surfaces are at 16°C, determine the maximum temperature to which the concrete will be subjected, assuming steady-state conditions. The thermal conductivity of the wet concrete can be taken as 0.84 W/m K.
A plane wall 15 cm thick has a thermal conductivity given by the relation k=2.0+0.0005T[W/mK] where T is in kelvin. If one surface of this wall is maintained at 150C and the other at 50C, determine the rate of heat transfer per square meter. Sketch the temperature distribution through the wall.
In steady state condition, the lateral surfaces of the plate are insulated, and the bottom surface is heated with a uniform heat flux. The thermal conductivity coefficient of the plate is k, and its upper surface is cooled by convection. a) Find the temperature distribution inside the plate. b) Find the temperatures at x = 0 and x = L. c) Find the amount of heat transfer transferred. NOTE: Assume one-dimensional heat conduction. h = 27 W/m2°C q" =624000W/m² k=15 W/m.°C T = 22°C L=256 cm
The steady-state temperature distribution in a one-dimensional wall of thermal conductivity k=83 (W/m) °C) and thickness 300 mm is observed to be T(°C) = ax2+bx+c, where a = -2500 °C/m2 , b = 500 °C/m, c = 250 °C and x is in meters. a) What is the heat generation rate ?̇ (W/m3 ) in the wall ? b) Find the maximum and minimum temperatures in the wall. c) Find the amount of heat transferred to the right side of the wall (for 1 m2 surface area.)
4) In an experiment to find the thermal conductivity, a metallic rod of diameter 25 mm is placed in a furnace such that its one half is inserted into the furnace and other half is projected out in a room at 300 K. Once the steady state reached, the temperatures measured between two points 76 mm apart were 399 K and 364 K, respectively. Taking a convection coefficient of 22.7 W/m 2 – K, find the thermal conductivity of the metal.
An external wall of a building has a U value of 0.50 W/m^2K. The indoor temperature is21 degrees C and the outdoor temperature is -2.0 degrees C The steady-state heat loss is calculated to be 11.5W/m^2 The wall contains a layer of insulation 40 mm thick with a conductivity of0.035 W/mK. What would the insulation thickness need to be in order toreduce the steady state heat loss by 50%? answer = 0.11m please show all working
54. As shown in the figure, to dissipate heat from an electrical appliance, thin plates of metal with a thermal conductivity of 10 Btu/h·ft·F are used. Find the number of the plates to dissipate 10.55 W at steady state operation. Data: Tbase = 85 F, Tf = 65 F, h = 1 Btu/h·ft2·F, L = 10 in, b = 1 in, δ = 0.03 in. [Ans.: 15].
Steam at 150 ° C flows in a pipe having an inner radius of 50 mm and an outer radius of 55 mm. The convective heat transfer coefficient between the steam and the inner pipe wall is 2500 W / (m² ° C). The outer surface of the pipe exposed to ambient air is 25 ° C with a convective heat transfer coefficient of 10 W / (m² ° C). Assuming steady state, calculate the rate of heat transfer per meter of pipe from steam to air. Assume that the thermal conductivity of stainless steel is 15 W / (m ° C.). Steps of work according to example 4.16 Singh. a. Find the overall heat transfer coefficient = Answer W / m² ° C. b. Heat transfer rate per meter of pipe = Answer
The front door of an oven is made up of walls made up of materials A, B and C, juxtaposed. The walls that make up the door have thermal conductivities, kA= 20 W/(m.K), kB= 0.027 W/(m.K) and kC= 50 W/(m.K) and known thicknesses LA=0.30 m and LC=0.15 m. At steady state operation, measurements indicate that the air temperatures inside the oven and its inner walls are equal to 600 oC (the temperature of the inner surface of the door is not known). The convective coefficient of air (inside and outside the oven) is 25 W/(m2.K) and the radiation coefficient is hr=25 W/m2K. outside the air is at 25oC. Based on this information:(a) schematic the thermal circuit for the system;(b) estimate the minimum thickness of wall B to ensure that thetemperature of the outer surface of the door (exposed to ambient air)is ≤40oC in order to ensure the safety of operators;(c) estimate the temperature of the surface of the oven's inner wall Answer: (b) 40 mm; (c) 592.5oC