Homework Answers
Add Answer to:
Problem 21–20 pts.: “Kitchen Oven Fiberglass Thickness” • How much fiberglass insulation (k = 0.035 W/m-K)...
QUESTION 1 The wall of a refrigerator is constructed of fiberglass insulation (k - 0.035 W/m...
QUESTION 1 The wall of a refrigerator is constructed of fiberglass insulation (k - 0.035 W/m "C) sandwiched between two layers of 1-mm-thick sheet metal (k-15.1 W/m. "C). The refrigerated space is maintained at 3°C, and the average heat transfer coefficients at the inner and outer surfaces of the wall are 4 W/m2. "C and 9 W/m2. C, respectively. The kitchen temperature averages 25°C. It is observed that condensation occurs on the outer surfaces of the refrigerator when the temperature...
For such aircraft application (Figure 3), a wall is made from insulation material (k-0.030 W/m.K) and...
For such aircraft application (Figure 3), a wall is made from insulation material (k-0.030 W/m.K) and the insulation material is mounted between four layers of carbon steel (2 mm thickness), the carbon layers are separated by a 2 mm air gap (kair-0.025 W/mK). Figure 3, the thermal conductivity of the carbon steel is (k-15.5 W/m.K). The temperature inside the wall is maintained at 6 °C. The environmental temperature is 24°C. The engineer would like to avoid condensation occurring at outer...
Superheated steam flows steadily through steel tubing (k 35 W/m-K) applying a tube inner surface temperature...
Superheated steam flows steadily through steel tubing (k 35 W/m-K) applying a tube inner surface temperature of 575°C. The tubing has an inner diameter of 300 mm and a wall thickness of 30 mm. Insulation (k 0.10 W/m-K) is applied to the outer surface of the tube while thin aluminum sheet is applied around the insulation as a protective covering. The ambient air at 27°C provides a convection coefficient of 6 W/m2-K. Determine the minimum insulation thickness necessary (mm) to...
Thermal Resistance Analysis: Consider a 1.2 m high and 1.4 m wide double-pane window consisting o...
Thermal Resistance Analysis: Consider a 1.2 m high and 1.4 m wide double-pane window consisting of two 4 mm thick layers ofglass (k-0.85 W m-K) separated by a 8-min stagnant air space. (k= 0.025 W m-K) Determine the steady rate of heat transfer through this double-pane window and the temperature of its inner and outer surfaces on a day when the inside room temperature is maintained at 20 °C and the outside ambient temperature is 32 °C. Assume the convection...
Questions 6-9 The walls of a refrigerator are typically constructed by sandwiching a layer of insulation...
Questions 6-9 The walls of a refrigerator are typically constructed by sandwiching a layer of insulation between sheet metal panels. Consider a wall made from fiberglass insulation of thermal conductivity ki = 0.046 W/mK and thickness Li 50 mm and steel panels, each of thermal conductivity kp = 60 W/m. K and thickness Lp = 3 mm. If the wall separates refrigerated air at Too,i = 4°C from ambient air at T0o,0 = 25°C, what is the heat gain per...
Problem 1: (10 points) The composite wall of an oven consists of three materials, two of...
Problem 1: (10 points) The composite wall of an oven consists of three materials, two of which are of known thermal conductivity, k 20 W/mK and ke-50 W/m.K, and known thickness, La 0.30 m and 0.15 m. The third material, B, which is sandwiched between materials A and C is of known thickness, 0.15 m, but unknown thermal conductivity ks. Under steady-state operating conditions, measurements reveal an outer surface temperature of 20°C, an inner surface temperature of T 600°C, and...
2-157 A long electrical resistance wire of radius r.-0.25 cm has a thermal conductivity kwire-15 W/m-K. Heat is gene...
2-157 A long electrical resistance wire of radius r.-0.25 cm has a thermal conductivity kwire-15 W/m-K. Heat is generated uniformly in the wire as a result of resistance heating at a constant rate of 0.5 W/cm3. The wire is covered with polyethylene insulation with a thickness of 0.25 cm and thermal conductivity of ks 0.4 W/m K. The outer surface of the insulation is subjected to free convection in air at 20°C and a convection heat transfer coefficient of 2...
(25pts) Consider a 1.2-m-high and 2-m-wide glass window whose thickness is 6 mm and thermal conductivity...
(25pts) Consider a 1.2-m-high and 2-m-wide glass window whose thickness is 6 mm and thermal conductivity is k 0.78 W/m °C. Determine the steady rate of heat transfer through this glass window and the temperature of its inner surface for a day during which the room is maintained at 24°C while the temperature of the outdoors is-5°C. Take the convection heat transfer coefficients on the inner and outer surfaces of the window to be h 10 W/m2 °C and h...
1. A steel tube [k 15 W/(m.°C)] of outside diameter 7.6 cm and thickness 1.3 cm...
1. A steel tube [k 15 W/(m.°C)] of outside diameter 7.6 cm and thickness 1.3 cm is covered with an insulation material [k 0.2 W/(m. C)] of thickness 2 cm. A hot gas at 320°C with a heat transfer coefficient of 200 W/(m2.C) flows inside the tube. The outer surface of the insulation is exposed to cooler air at 20°C with a heat transfer coefficient of 50 W/(m2·°C). Calculate a) The heat loss from the tube to the air for...
a) what is the heat loss per unit length from the pipe in W/m? b) Estimate...
a) what is the heat loss per unit length from the pipe in
W/m?
b) Estimate the heat loss per unit length if a 50 mm thick layer
of insulation with a conductivity of 0.058 W/m K. Neglect radiation
for this part.
3. A 0.20-m diameter, thin-walled steel pipe is used to transport saturated steam at a temperature of 486K in a room for which the air temperature is 25°C and convection heat transfer coefficient at the outer surface of...
For such aircraft application (Figure 3), a wall is made from insulation material (k-0.030 W/m.K) and the insulation material is mounted between four layers of carbon steel (2 mm thickness), the carbon layers are separated by a 2 mm air gap (kair-0.025 W/mK). Figure 3, the thermal conductivity of the carbon steel is (k-15.5 W/m.K). The temperature inside the wall is maintained at 6 °C. The environmental temperature is 24°C. The engineer would like to avoid condensation occurring at outer...
Superheated steam flows steadily through steel tubing (k 35 W/m-K) applying a tube inner surface temperature of 575°C. The tubing has an inner diameter of 300 mm and a wall thickness of 30 mm. Insulation (k 0.10 W/m-K) is applied to the outer surface of the tube while thin aluminum sheet is applied around the insulation as a protective covering. The ambient air at 27°C provides a convection coefficient of 6 W/m2-K. Determine the minimum insulation thickness necessary (mm) to...
Thermal Resistance Analysis: Consider a 1.2 m high and 1.4 m wide double-pane window consisting of two 4 mm thick layers ofglass (k-0.85 W m-K) separated by a 8-min stagnant air space. (k= 0.025 W m-K) Determine the steady rate of heat transfer through this double-pane window and the temperature of its inner and outer surfaces on a day when the inside room temperature is maintained at 20 °C and the outside ambient temperature is 32 °C. Assume the convection...
Questions 6-9 The walls of a refrigerator are typically constructed by sandwiching a layer of insulation between sheet metal panels. Consider a wall made from fiberglass insulation of thermal conductivity ki = 0.046 W/mK and thickness Li 50 mm and steel panels, each of thermal conductivity kp = 60 W/m. K and thickness Lp = 3 mm. If the wall separates refrigerated air at Too,i = 4°C from ambient air at T0o,0 = 25°C, what is the heat gain per...
Problem 1: (10 points) The composite wall of an oven consists of three materials, two of which are of known thermal conductivity, k 20 W/mK and ke-50 W/m.K, and known thickness, La 0.30 m and 0.15 m. The third material, B, which is sandwiched between materials A and C is of known thickness, 0.15 m, but unknown thermal conductivity ks. Under steady-state operating conditions, measurements reveal an outer surface temperature of 20°C, an inner surface temperature of T 600°C, and...
2-157 A long electrical resistance wire of radius r.-0.25 cm has a thermal conductivity kwire-15 W/m-K. Heat is generated uniformly in the wire as a result of resistance heating at a constant rate of 0.5 W/cm3. The wire is covered with polyethylene insulation with a thickness of 0.25 cm and thermal conductivity of ks 0.4 W/m K. The outer surface of the insulation is subjected to free convection in air at 20°C and a convection heat transfer coefficient of 2...
(25pts) Consider a 1.2-m-high and 2-m-wide glass window whose thickness is 6 mm and thermal conductivity is k 0.78 W/m °C. Determine the steady rate of heat transfer through this glass window and the temperature of its inner surface for a day during which the room is maintained at 24°C while the temperature of the outdoors is-5°C. Take the convection heat transfer coefficients on the inner and outer surfaces of the window to be h 10 W/m2 °C and h...
1. A steel tube [k 15 W/(m.°C)] of outside diameter 7.6 cm and thickness 1.3 cm is covered with an insulation material [k 0.2 W/(m. C)] of thickness 2 cm. A hot gas at 320°C with a heat transfer coefficient of 200 W/(m2.C) flows inside the tube. The outer surface of the insulation is exposed to cooler air at 20°C with a heat transfer coefficient of 50 W/(m2·°C). Calculate a) The heat loss from the tube to the air for...
a) what is the heat loss per unit length from the pipe in
W/m?
b) Estimate the heat loss per unit length if a 50 mm thick layer
of insulation with a conductivity of 0.058 W/m K. Neglect radiation
for this part.
3. A 0.20-m diameter, thin-walled steel pipe is used to transport saturated steam at a temperature of 486K in a room for which the air temperature is 25°C and convection heat transfer coefficient at the outer surface of...
Most questions answered within 3 hours.
-
1. What is the meaning of the term communication style?
2. What are the benefits to...
asked 34 minutes ago -
9.) You are buying a car that cost $26,500. You make payments of
$412 each month...
asked 59 minutes ago -
. Suppose a discrete random variable has probability
distribution
P(x) = .2 if x = 0...
asked 2 hours ago -
Problem #1
The area between Z = 0 and Z = 2.50
The area between Z...
asked 1 hour ago -
Under the influence of its drive force, a snowmobile is moving
at a constant velocity along...
asked 2 hours ago -
Why do organizations decline? What steps can top
management take to halt, decline, and restore organizational...
asked 2 hours ago -
What mechanisms Drive speciation??
(I.e. what was Dawins theory on the orgin of species, and how...
asked 4 hours ago -
The manager at a car assembly plant believes that the mean
assembly time for a car...
asked 4 hours ago -
Which of the following is true of electron capture?
A) It decreases the nuclide's mass number...
asked 6 hours ago -
Assuming an efficiency of 43.10%, calculate the actual yield of
magnesium nitrate formed from 114.9 g...
asked 7 hours ago -
The highly pathogenic bacterium Clostridium
perfringens causes gangrene, a disease that results in the
destruction of...
asked 8 hours ago -
In the context of situation analysis, which of the following is
a category for analysis in...
asked 8 hours ago