Question

In: Mechanical Engineering

An 8-m-long, uninsulated square duct of cross section 0.2 m X 0.2 m and relative roughness...

An 8-m-long, uninsulated square duct of cross section 0.2 m X 0.2 m and relative roughness 10-3 passes through the attic space of a house. Hot air enters the duct at 1 atm and 91oC at a volume flow rate of 0.15 m3/s. The duct surface is nearly isothermal at 60oC. Determine the rate of heat loss from the duct to the attic space and the pressure difference between the inlet and outlet sections of the duct. Evaluate air properties at a bulk mean temperature of 80oC. Is this a good assumption? Taking a bulk mean fluid temperature of 80oC based on the problem statement (this assumes that the air does not loose much heat to the attic), the properties of air are: cp = 1008 J/kg∙oC k = 0.02953 W/m∙oC ν = 2.097 × 10-5 m2/s ρ = 0.9994 kg/m3 Pr = 0.7154

Solutions

Expert Solution

samet mamat answered 2 years ago
Next > < Previous

Related Solutions

An aluminum rod with a square cross section is 1.2 m long and 5.0 mm on...
An aluminum rod with a square cross section is 1.2 m long and 5.0 mm on edge. (a) What is the resistance between its ends? (b) What must be the diameter of a cylindrical copper rod of length 1.2 m if its resistance is to be the same as that of the aluminum rod? The resistivity of aluminum is 2.75 × 10-8 Ω·m and the resistivity of copper is 1.69 × 10-8 Ω·m.
A water trough is 8 m long and has a cross-section in the shape of an...
A water trough is 8 m long and has a cross-section in the shape of an isosceles trapezoid that is 30 cm wide at the bottom, 80 cm wide at the top, and has height 50 cm. If the trough is being filled with water at the rate of 0.1 m3/min how fast is the water level rising when the water is 40 cm deep?
A water trough is 8 m long and has a cross-section in the shape of an...
A water trough is 8 m long and has a cross-section in the shape of an isosceles trapezoid that is 30 cm wide at the bottom, 70 cm wide at the top, and has height 40 cm. If the trough is being filled with water at the rate of 0.3 m3/min how fast is the water level rising when the water is 20 cm deep?
Air flows through a heating duct with a square cross-section with 5-inch sides at a speed...
Air flows through a heating duct with a square cross-section with 5-inch sides at a speed of 5.3 ft/s. Just before reaching an outlet in the floor of a room, the duct widens to assume a square cross-section with sides equal to 13 inches. Compute the speed of the air flowing into the room (in ft/s), assuming that we can treat the air as an incompressible fluid. Answer should be in Ft/s
Airflow through a long, 0.15-m-square air conditioning duct maintains the outer duct surface temperature at 10°C....
Airflow through a long, 0.15-m-square air conditioning duct maintains the outer duct surface temperature at 10°C. If the horizontal duct is uninsulated and exposed to air at 35°C in the crawlspace beneath a home, what is the heat gain per unit length of the duct? Evaluate the properties of air at 300 K. For the sides of the duct, use the more accurate Churchill and Chu correlations for laminar flow on vertical plates. What is the Rayleigh number for free...
A beam with a cross-section of 0.3 m x 0.7 m has an effective depth of...
A beam with a cross-section of 0.3 m x 0.7 m has an effective depth of 0.638 m and a span of 4.30 m. Use the following data below to determine (a) the steel requirement due to flexure, (b) ultimate threshold torsion, and (c) spacing of stirrup due to combined shear and torsion: Mu = 322 KN-m Vu = 317 KN Tu = 42 KN-m f'c =28 MPa fyt = 414 MPa 12 mm stirrup diameter cover of 0.04 m
A fluidic storage tank has a square cross-section (3m x 3m) and a height of 10m....
A fluidic storage tank has a square cross-section (3m x 3m) and a height of 10m. The tank is half-filled with a fluid with the density of 200kg/m3. The tank suddenly develops a leak. A sensor inside the tank instantaneously alerts the owner that the height of the fluid in the tank is decreasing by 1mm/min. Find the flow rate out of the tank at that moment in time.
A 4-m-high and 6-m-wide wall consists of a long 18x30 cm2 cross section of horizontal bricks...
A 4-m-high and 6-m-wide wall consists of a long 18x30 cm2 cross section of horizontal bricks (K=0.72W/mC) separated by 3-cm-thick plaster layer (K=0.22W/mC). There are also 2-cm-thick plaster layers on each side of the wall, and a 2-cm-thick rigid form (K=0.026W/mC) on the inner side of the wall. The indoor and outdoor temperatures are 22C and -4 C, and the combined convection and radiation heat transfer coefficients on the inner and outer walls are 10W/m2C and 20W/m2C, respectively. Determine the...
Determine the limiting values of the width a of a waveguide of square cross section which...
Determine the limiting values of the width a of a waveguide of square cross section which will transmit a wave of length lambda in the TE10 mode but not in the TE11 or TM11 modes.
Consider the following data: x 4 5 6 7 8 P(X=x) 0.2 0.2 0.1 0.2 0.3...
Consider the following data: x 4 5 6 7 8 P(X=x) 0.2 0.2 0.1 0.2 0.3 Step 2 of 5: Find the variance. Round your answer to one decimal place. Step 3 of 5: Find the standard deviation. Round your answer to one decimal place. Step 4 of 5: Find the value of P(X<7). Round your answer to one decimal place Step 5 of 5:Find the value of P(X≥7). Round your answer to one decimal place.
ADVERTISEMENT
Subjects
ADVERTISEMENT
Latest Questions
ADVERTISEMENT