An electrical cable is insulated with a material with k of 10W/mK. The convection heat transfer coefficient is 5 W/m2K. For what insulation thickness radius, the total heat transfer resistance will be minimum? • Im 2m O 5m 10m 02cm 05cm

An electrical cable is insulated with a material with k of 10W/mK. The convection heat transfer coefficient is 5 W/m2K. For what insulation thickness radius, the total heat transfer resistance will be minimum? • Im 2m O 5m 10m 02cm 05cm

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

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Insulating material is used to reduce heat loss from the heating furnace walls to the room. The surface temperature of the insulating material is 100 ° C and the other surfaces 20 ° C. Allowable heat loss up to 140 W / m2 from the wall. If the thermal conductivity of the insulation material is 0.05 W / (m ° C), calculate the required thickness of insulation. insulation thickness = Answer cm
Steel pipe (outer diameter 100 mm) is covered with two layers of insulation. The inner layer, 40 mm thick, has a thermal conductivity of 0.07 W / (m K). The outer layer, 20 mm thick, has a thermal conductivity of 0.15 W / (m K). Pipes are used to deliver steam with a pressure of 700 kPa. The temperature on the outer insulation surface is 24 ° C. If the pipe is 12 m long, determine the following: (assuming that the conduction heat transfer resistance of the steel pipe and the vapor convection resistance are negligible). a. Heat loss per hour. = Answer kJ / hour. b. Temperature between insulation layers. = Answer ° C.
1. A pipe is covered with three insulation layers where the corresponding thicknesses are 150 mm, 250mm and 300mm and the respective thermal conductivities are 3.2 W/m°C, 2.1 W/m°C and 1.5 W/m C. The length of the pipe is 3m. The inner side of the pipe which has a diameter of 300 mm is exposed to a hot gas at 1000 °C with convection coefficient of 50 W/m2°C and the temperature of the inner side of the pipe surface is 800 °C. The air outside the pipe is at 25°C with a convection coefficient of 35 W/m2°C. a. Draw a schematic diagram which shows the heat transfer process b. Calculate the Heat transfer rate c. The overall heat transfer coefficient "U" of the system based on the inner pipe d. Temperature at each of the layers and at the outermost surface of the pipe.
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Heat transfer
Please solve this question in thermodynamics
Temperature distribution of a wall is given as T(x) = -100x + 50 and the cold surface is exposed to a convection environment at temperature of 20 °C. If the wall thickness is 10 cm and the conductivity is 1 W/mK what is the convection coefficient between the cold surface and the environment?
Steel pipe (outer diameter 100 mm) is covered with two layers of insulation. The inner layer, 40 mm thick, has a thermal conductivity of 0.07 W / (m K). The outer layer, 20 mm thick, has a thermal conductivity of 0.15 W / (m K). Pipes are used to deliver steam with a pressure of 800 kPa. The temperature on the outer insulation surface is 24 ° C. If the pipe is 10 m long, determine the following: (assuming that the conduction heat transfer resistance of the steel pipe and the vapor convection resistance are negligible). a. Heat loss per hour. = Answer kJ / hour. b. Temperature between insulation layers. = Answer ° C.
Temp base is 156 not 456 as in the diagram
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