Consider a thick spherical wall with insulation at boththe inner and outer walls. The inner and outer radii of the 3-layersphere are 1₂ = 40 cm and r3 = 80 cm, respectively. Thelength of cylinder is 1 meter. The thermal conductivity of the wallis k₂= 120- 0 . The thickness of outer insulation is 5 cm and itswallk2 = 120 W/mKb.c.r3= 80 cm2 = 40 cmWthermal conductivity is k3 = 12 . The thickness of the innerinsulation is also 5 cm, but the thermal conductivity is k₁ =W8 The heat dissipates through the surface of outer sides ofmkthe insulation through convention with ho = 50. and theWm²Kambient temperature outside the pipe is To = 25°C. The inner most surface is maintained at100°C. Use resistance models to solve this problem.a. Compute the heat transfer through the wallr1 = 35 cminner insulationk1 = 8 W/mKr4 = 85 cmouter insulationk3 = 12 W/mKCompute the temperature of the outer most surface of the sphereCompute the heat transfer when thickness the outer most insulator is quadrupled - sothe outer most radius r4 = 100 cm. Comparing to the previous outcome (part a), doesthe heat transfer rate make sense?

Answered: Image /qna-images/answer/224988c9-6ee1-46d9-8cf6-33ab47620e9d.jpg

Consider a thick spherical wall with insulation at both mk mk the inner and outer walls. The inner and outer radii of the 3-layer sphere are ₂ = 40 cm and r3 = 80 cm, respectively. The length of cylinder is 1 meter. The thermal conductivity of the wall is k₂ = 120 . The thickness of outer insulation is 5 cm and its thermal conductivity is k3 = 12 The thickness of the inner insulation is also 5 cm, but the thermal conductivity is k₁ = 8 The heat dissipates through the surface of outer sides of the insulation through convention with ho = 50- and the ambient temperature outside the pipe is Too = 25°C. The inner most surface is maintained at 100°C. Use resistance models to solve this problem. mk W m²K a. Compute the heat transfer through the wall b. Compute the temperature of the outer most surface of the sphere wall k2 = 120 W/mK r3=80 cm 2 = 40 cm r1 = 35 cm inner insulation k1 = 8 W/mK r4 = 85 cm outer insulation k3= 12 W/mK

Consider a thick spherical wall with insulation at both mk mk the inner and outer walls. The inner and outer radii of the 3-layer sphere are ₂ = 40 cm and r3 = 80 cm, respectively. The length of cylinder is 1 meter. The thermal conductivity of the wall is k₂ = 120 . The thickness of outer insulation is 5 cm and its thermal conductivity is k3 = 12 The thickness of the inner insulation is also 5 cm, but the thermal conductivity is k₁ = 8 The heat dissipates through the surface of outer sides of the insulation through convention with ho = 50- and the ambient temperature outside the pipe is Too = 25°C. The inner most surface is maintained at 100°C. Use resistance models to solve this problem. mk W m²K a. Compute the heat transfer through the wall b. Compute the temperature of the outer most surface of the sphere wall k2 = 120 W/mK r3=80 cm 2 = 40 cm r1 = 35 cm inner insulation k1 = 8 W/mK r4 = 85 cm outer insulation k3= 12 W/mK

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

See similar textbooks

Similar questions

Answer this ASAP,thx An empty sphere is made of aluminum (k = 202 W/m. °C) with an inner diameter of 4 cm and an outer diameter of 8 cm. The inside temperature is 100°C and If the ball above is coated with an insulating material having k = 50 mW/m. °C 1 cm thick. The outside of this insulation is in contact with an environment having h = 20 W/m.°C and Ts = 10°C, calculate the heat transfer under these conditions.
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?
The exterior wall of a house is composed of a 20 cm thick layer of ordinary brick (conductivity 0.72 W/m K) and a 2.5 cm layer of plaster (conductivity 0.17 W/m K ) on each side (two layers in total). Other purely conductive resistances can be neglected, such as the layer of paint on both sides of the wall. Assume the outer face of the wall is at 35 °C and the inner face is at 20 °C and fill in the gaps. The magnitude of the heat flux through the wall corresponds to the _________ W/m2 and is perpendicular to the wall ________________(fill in with "outside-in" or "inside-out") of the environment. If the wall has a total area of 300m2, the heat transfer rate corresponds to ___________________
In a composite slab, the temperature at the interface (Tinter ) between two materials is equal to the average of the temperature at the two ends. Assuming steady one dimensional heat conduction, which of the following statements is true about the respective thermal conductivities?
A multi-layered wall with the dimensions shown in the figure has temperatures of 200°C and 50°C over the left and right surfaces, respectively. If the thermal conductivities of the wall materials A and C are k-60 W/m-K, k-24 W/m-K. If total rate of heat transfer through the wall is 175 W, what is the thermal conductivity of material B? T- 200°C T-soc 6 cm- 2 om 25 om
A semiconductor material has a conductivity of 0.0124 W/cm-K. It has the shape of a rectangular bar with cross sectional area of 1 cm2and length of 3 cm. One end is maintained at 300 °C and the other end at 100 °C. The bar carries a current of 50 A and has resistivity of 1.5x10-3ohm-cm. Assuming the longitudinal surface is insulated, calculated the midpoint temperature in the bar.
A cylindrical pipe is made up of two materials. The inner material A, which has thermal conductivity of ka, has inner radius ra and outer radius re. On the other hand, the outer material B, which has thermal conductivity of kb, has inner radius re and outer radius rb. Contact resistance between the two materials is known to be hc. The temperature at the inner radius of material A (at ra) is Ta, while the temperature at the outer radius of material B (at ri) is T3. Find an expression for the temperature at the inner radius of material B (at r.) in terms of the given variables.
The fin shown in Figure is insulated on the perimeter. The left end has a constant temperature of 100 °C. A positive heat flux of q = 5000 W/m² acts on the right end. Let Ky = 10 W/(m °C) and cross-sectional area A = 0.1 m2 Determine the temperatures at L/4, L/2, 3L/4, and L, where L = 0.8 m. 4-0.1 m T-100 C 5000 W/m
Shown in the figure below is an insulated copper block that receives energy at a rate of 200 W from an embedded resistor. The temperature of the resistor is 34°C above the temperature of the copper block. Insulation Δt = Resistor 5000000000000000000000 oooooooooooooo....... Copper block If the block has a volume of 10-3 m³ and an initial temperature of 20°C, how long would it take, in minutes, for the temperature to reach 88°C? -V=10-³ m³ T₁ = 20°C min
As2 Calculate the temperature 7 cm into the mineral wool layer from the warm side measured in one wall that is built from the outside in according to the following material layers: Wood panel ventilated R = 0.20 m2K / W Mineral wool 200 mm λ = 0.033 W / mK Plastic foil R ≈ 0 m2K / W Plasterboard 13 mm λ = 0.22 W / mK The temperature outside is -10 ◦C and inside 22 ◦C. The heat transfer resistors are on the inside Rsi = 0, 13 and on the outside Rse = 0, 04 m2K / W
A hot water pipe is used for domestic applications is insulated with a layer of calcium silicate. If the insulation is 25 mm thick and its inner and outer surfaces are maintained at Ts,1 = 800 K and Ts,2 = 400 K, respectively. The outside diameter is 0.12 m. Calculate the heat loss per unit length of the pipe. Given the thermal conductivity of calcium silicate insulation equals to 0.09 W/m.K.
Consider the 2D heat conduction problem for a plane fin in the figure. Non-dimensionalize the problem in the figure.