During a performance test of an insulation wall, a 2 m longx3-m wide portion of the wall is placed in a wind tunnel. The wall is made of 1.2 cm thick siding, 20 cm thick brick, and 1 cm thick plaster layers. The test holds one side of the wall surface (the plaster surface) constant at 20°C as shown in the figure. During the test, air is flown parallel to the 2-m side of the wall over the other side (i.e., over the siding) of the wall. The air temperature is -15°C. The free-stream velocity of air is 5 m/s. Assume a film temperature of -10°C for air. Find out the rate of heat loss through the wall (i.e., from the rightmost surface in the figure to air on the left) during the test. Justify if the assumed value of film temperature is reasonable. The thermal conductivity of the siding, brick, and plaster are, respectively, 0.09 W/m-K, 0.7 W/m-K, and 0.82 W/m-K. Neglect radiation effects. 403 W - 15 °C Cold air flow ↓ Siding Wind- tunnel → side Brick Plaster Inside, kept at constant temp

During a performance test of an insulation wall, a 2 m longx3-m wide portion of the wall is placed in a wind tunnel. The wall is made of 1.2 cm thick siding, 20 cm thick brick, and 1 cm thick plaster layers. The test holds one side of the wall surface (the plaster surface) constant at 20°C as shown in the figure. During the test, air is flown parallel to the 2-m side of the wall over the other side (i.e., over the siding) of the wall. The air temperature is -15°C. The free-stream velocity of air is 5 m/s. Assume a film temperature of -10°C for air. Find out the rate of heat loss through the wall (i.e., from the rightmost surface in the figure to air on the left) during the test. Justify if the assumed value of film temperature is reasonable. The thermal conductivity of the siding, brick, and plaster are, respectively, 0.09 W/m-K, 0.7 W/m-K, and 0.82 W/m-K. Neglect radiation effects. 403 W - 15 °C Cold air flow ↓ Siding Wind- tunnel → side Brick Plaster Inside, kept at constant temp

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.

Chapter5: Analysis Of Convection Heat Transfer

Section: Chapter Questions

Problem 5.57P

See similar textbooks

Similar questions

During a performance test of an insulation wall, a 2 m long-3-m wide portion of the wall is placed in a wind tunnel. The wall is made of 1.2 cm thick siding, 20 cm thick brick, and 1 cm thick plaster layers. The test holds one side of the wall surface (the plaster surface) constant at 20°C as shown in the figure. During the test, air is flown parallel to the 2-m side of the wall over the other side (i.e., over the siding) of the wall. The air temperature is -15°C. The free-stream velocity of air is 5 m/s. Assume a film temperature of −10°C for air. Find out the rate of heat loss through the wall (i.e., from the rightmost surface in the figure to air on the left) during the test. Justify if the assumed value of film temperature is reasonable. The thermal conductivity of the siding, brick, and plaster are, respectively, 0.09 W/m-K, 0.7 W/mK, and 0.82 W/m.K. Neglect radiation effects. 403 W Siding Plaster - 15 °C Cold air flow ↓ Wind- tunnel side Inside, kept at constant temp Brick 20 °C
Line AB was measured to be 2465.75 m when using a 100 m steel tape supported only at the ends under a pull of 9 kg and a mean temperature of 40°C. The tape is of standard length at 35 °C at a pullof 10 kg. The cross sectional area of the tape is 0.035 cm.?. Determine the correct length AB.
-2- Determine the temperature distribution in the thermal boundary layer assuming third degree polynomial: T(x, y)=b, +b,y +b,y² +b,y
A cylindrical bottle with a diameter of 10 cm and a height of 30 cm contains cold water at 3 °C. The bottle is placed in windy air at 27°C. The temperature of the water is measured at 11 °C after 45 minutes of contact with the air. Neglecting radiation effects and heat transfer from the upper and lower surfaces, estimate the average wind speed. I need the solution from fundamental concepts of how the heat flow behaves in the system
Write a question about the amount heat carried away by convection after you have taken X= 14 breaths on a cold day. Feel free to look up reasonable estimates of temperature, the heat capacity of air, and lung capacity. Show work please and thank you in advance
What is the rate of heat loss through a 4-cm Fiberglass wall of the inside temperature is 22 °C and the outside temperature is 45 °C and windy (17 kph) ? the area of the wall is 100 square meters. Include surface films. Assume the k-value for 4-cm fiberglass is 0.056 W/m. °C and the surface air film coefficient for windy velocity (17 kph) is 0.053 for out film and the inner film Rs value is 0.093 as per the surface film coefficient tables ?
A brass rod 125.00 mm long and 5.00 mm in diameter extends horizontally from a casting at 200°C. The rod is in an air environment with T = 20°C and h = 30W/m2.K. What is the temperature of the rod 31.25, 62.50, and 125.00 mm from the casting? T31.25 = i °C T62.50 = i °C T125.00 i °C %3D
3.130 A brass rod 100 mm long and 5 mm in diameter extends horizontally from a casting at 200°C. The rod is in an air environment with T = 20°C and h = 30 W/m²K. What is the temperature of the rod 25, 50, and 100 mm from the casting? 8
Two flat infinite slabs, each 5 m thick, are each initially uniform in temperature, with one being at 0° and the other at 20°. At t=0, the two slabs are stacked together (the warmer one at larger y) and both the top and bottom surfaces of the stack are kept at 0°. Find the temperature in the stacked slabs as a function of y and t for t > 0. Write out the heat flow equation, find the general solution, and the specific solution for this arrangement.
4. During a cold winter day, wind blows parallel to a 4 m high and 10 m long wall of a house. If the air outside is at 5°C and the surface temperature of the wall is 15°C, The general non-dimensional correlation for flow over a flat plate is: Nu =(0.037 Re, 0.8-871) Pr¹/3 where the fluid properties are evaluated at the bulk temperature. If the wind blows at 55 km/h, determine: i. the Reynolds number ii. the convection heat transfer coefficient, and iii. the rate of heat transfer from the wall.
A 5.0-cm-diameter cylinder is heated to a temperature of 200°C, and air at 30 °C forced across it at a velocity of 50 m/s (h = 180 W/m2 K). If the surface emissivity is 0.7, calculate the total heat loss per unit length if the walls of the enclosing room are at 10 °C. Comment on your calculation.
Fruit is impeded from ripening when it reaches high temperatures (>32°C). Farmer Joe isworried that Deleware's summer heat wave will affect the ripening of his ground cherries.The spherical fruit (1 cm in diameter) is surrounded by a spherical papery husk (λhusk = 0.3W/m K) with an inner diameter of 2 cm and an outer diameter of 2.1 cm. The air in betweenthe fruit and the husk is stagnant (λair = 0.03 W/m K). On a calm day in July, the delewareair (outside of the husk) is very warm, with a temperature of ~38°C and a heat transfercoefficient of h deleware,calm = 10 W/m 2K. (a) Sketch the system, labeling all temperatures, dimensions, and proportionality constants. (b) sketch the electrical analogy tothis system, labeling all temperatures, resistances, and heat flows (c) what is the overall resistance to heat transfer from the air in Deleware to the fruit?