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A silver sphere (k = 429 W/m.°C.p = 10,500 kg/m", Cp=0.235 kJ/kg-°C) is initially at 0°C....
QUESTION TWO Carbon steel balls (p 7833 kg/m3, k-54 W/m K, cp 0.465 kJ/kg.0C and a-1.474...
QUESTION TWO Carbon steel balls (p 7833 kg/m3, k-54 W/m K, cp 0.465 kJ/kg.0C and a-1.474 x 10-6 m2/s) 10 mm in diameter are annealed by heating them first to 900'C in a furnace and then allowing them to cool slowly to 100°C in ambient air at 35°C. If the average heat transfer coefficient is 75 W/m2 K, determine how long the annealing process will take. If 2500 balls are to be annealed per hour, determine the total rate of...
6. Solar radiation (525 W/m?) hits a concrete (p=1190 kg/m', k=0.5 W/m-K, Cp = 0.8 kJ/kg-K,...
6. Solar radiation (525 W/m?) hits a concrete (p=1190 kg/m', k=0.5 W/m-K, Cp = 0.8 kJ/kg-K, a = 5 x 10-7 m/s) parking lot initially at 4°C. What will be the temperature (°C) 9.4 cm below the surface after 24 hours? Ignore convection and radiation from the concrete. (14 pts).
Problem 2. A long 6.5 cm diameter solid cylinder steel (K 16.3 W/m. K,p 7817 kg/m3,...
Problem 2. A long 6.5 cm diameter solid cylinder steel (K 16.3 W/m. K,p 7817 kg/m3, Cp 460 J/kg.k). It's initially at a uniform temperature of T 150°C. It is suddenly exposed to a convection environment with h-285 W/m2 K and Too 50°C. Calculate the temperature at 1.) the axis of the cylinder, and 2.) a 2.5 cm radial distance after 5 min of exposure to the cooling flow. (20%)
SKMM 3433 A solid body which is initially at a uniform temperature Tİ is exposed to an ambient air at temperature Te. Explain how you would determine the maximum amount of heat that can be transfe...
SKMM 3433 A solid body which is initially at a uniform temperature Tİ is exposed to an ambient air at temperature Te. Explain how you would determine the maximum amount of heat that can be transferred to the body. What does this amount of heat represent? Q2. (a) (5 marks) A wall ofa room is made of lightweight concrete material (ρ= 1600 kg/m.に0.79 W/m K and cp 0.84 kJ/kg K) with a thickness of 150 mm. Initially the wall is...
Q2 (a) A 12 mm diameter mild steel sphere (k = 42.5 W/m K) is exposed...
Q2 (a) A 12 mm diameter mild steel sphere (k = 42.5 W/m K) is exposed to cooling airflow at 27 "C resulting in the convective coefficient, h = 114 W/m' K. The relevant properties of mild steel are given as follows: Density p= 7850 kg/m . Specific heat c = 475 J/kg K and thermal diffusivity a = 0.043 m/hr Determine: (i) Time required to cool the sphere (lumped parameter system) from 540 °C to 95°C. [7 marks] (ii)...
1)(Hint: Cp=1.005 kJ/kg-K, Cv=0.718 kJ/kg-K, R=0.287 kJ/kg-K). An air-tight room contains 80 kg of air, and...
1)(Hint: Cp=1.005 kJ/kg-K, Cv=0.718 kJ/kg-K, R=0.287 kJ/kg-K). An air-tight room contains 80 kg of air, and a 2-kW baseboard electric resistance heater in the room is turned on and kept on for 15 min. The temperature rise of air at the end of 15 min is 2)An example of when it is appropriate to model a substance as an ideal gas is when a. The pressure and temperature are close to the critcal point b. The pressure and temperature are...
Chilled water enters a thin-shelled 5-cm-diameter, 150-m-long pipe at 7°C at a rate of 0.98 kg/s...
Chilled water enters a thin-shelled 5-cm-diameter, 150-m-long pipe at 7°C at a rate of 0.98 kg/s and leaves at 8°C. The pipe is exposed to ambient air at 30°C with a heat transfer coefficient of 9 W/m2.K. If the pipe is to be insulated with glass wool insulation (k0.05 W/m-K) in order to decrease the temperature rise of water to 0.25°C, determine the required thickness of the insulation.
P2) (50 pts.) A sphere of radius , and thermal conductivity of k=0.1 W/ mK is...
P2) (50 pts.) A sphere of radius , and thermal conductivity of k=0.1 W/ mK is generating heat at a constant rate in W/m] inside another sphere of radius ry. The radius of the internal sphere is a 10 cm and the radius of the outer sphere is 40 cm. The outer surface is exposed to ambient air at 27°C and a convection coethicient -30 W/m-K. The thermal conductivity of the external sphere is 6.0 W/m-K. If the temperature at...
constant specife heats An ideal gas wit of cp .1 kJ/(kg K) and c 0.75 kJ/(kg...
constant specife heats An ideal gas wit of cp .1 kJ/(kg K) and c 0.75 kJ/(kg K) is contained in the piston-cylinder device shown. Initially, the vol- ume is 50 cm3 and the temperature is 20°C. How much heat must be added to double the volume if the final pressure and temperature are 400 kPa and 1000 K respectively. g·K) and Cu- Ideal gas Linear spring
2. A separation column at a temperature of 100C is subjected for cooling for a certain...
2. A separation column at a temperature of 100C is subjected
for cooling for a certain period of time. If the separation column
is 1500 mm high and 18 cm in diameter, and eventually exposed to an
environment temperature of 35C, determine the following with a
neat diagram:
a) Heat Transfer Coefficient (in J/s m2C and kJ/s m2C)
b) Heat transfer Rate (in W and kW)
Assume the properties of air at mean temperature as density
(ρ) = 1.06 kg/m3,...
QUESTION TWO Carbon steel balls (p 7833 kg/m3, k-54 W/m K, cp 0.465 kJ/kg.0C and a-1.474 x 10-6 m2/s) 10 mm in diameter are annealed by heating them first to 900'C in a furnace and then allowing them to cool slowly to 100°C in ambient air at 35°C. If the average heat transfer coefficient is 75 W/m2 K, determine how long the annealing process will take. If 2500 balls are to be annealed per hour, determine the total rate of...
6. Solar radiation (525 W/m?) hits a concrete (p=1190 kg/m', k=0.5 W/m-K, Cp = 0.8 kJ/kg-K, a = 5 x 10-7 m/s) parking lot initially at 4°C. What will be the temperature (°C) 9.4 cm below the surface after 24 hours? Ignore convection and radiation from the concrete. (14 pts).
Problem 2. A long 6.5 cm diameter solid cylinder steel (K 16.3 W/m. K,p 7817 kg/m3, Cp 460 J/kg.k). It's initially at a uniform temperature of T 150°C. It is suddenly exposed to a convection environment with h-285 W/m2 K and Too 50°C. Calculate the temperature at 1.) the axis of the cylinder, and 2.) a 2.5 cm radial distance after 5 min of exposure to the cooling flow. (20%)
SKMM 3433 A solid body which is initially at a uniform temperature Tİ is exposed to an ambient air at temperature Te. Explain how you would determine the maximum amount of heat that can be transferred to the body. What does this amount of heat represent? Q2. (a) (5 marks) A wall ofa room is made of lightweight concrete material (ρ= 1600 kg/m.に0.79 W/m K and cp 0.84 kJ/kg K) with a thickness of 150 mm. Initially the wall is...
Q2 (a) A 12 mm diameter mild steel sphere (k = 42.5 W/m K) is exposed to cooling airflow at 27 "C resulting in the convective coefficient, h = 114 W/m' K. The relevant properties of mild steel are given as follows: Density p= 7850 kg/m . Specific heat c = 475 J/kg K and thermal diffusivity a = 0.043 m/hr Determine: (i) Time required to cool the sphere (lumped parameter system) from 540 °C to 95°C. [7 marks] (ii)...
Chilled water enters a thin-shelled 5-cm-diameter, 150-m-long pipe at 7°C at a rate of 0.98 kg/s and leaves at 8°C. The pipe is exposed to ambient air at 30°C with a heat transfer coefficient of 9 W/m2.K. If the pipe is to be insulated with glass wool insulation (k0.05 W/m-K) in order to decrease the temperature rise of water to 0.25°C, determine the required thickness of the insulation.
P2) (50 pts.) A sphere of radius , and thermal conductivity of k=0.1 W/ mK is generating heat at a constant rate in W/m] inside another sphere of radius ry. The radius of the internal sphere is a 10 cm and the radius of the outer sphere is 40 cm. The outer surface is exposed to ambient air at 27°C and a convection coethicient -30 W/m-K. The thermal conductivity of the external sphere is 6.0 W/m-K. If the temperature at...
constant specife heats An ideal gas wit of cp .1 kJ/(kg K) and c 0.75 kJ/(kg K) is contained in the piston-cylinder device shown. Initially, the vol- ume is 50 cm3 and the temperature is 20°C. How much heat must be added to double the volume if the final pressure and temperature are 400 kPa and 1000 K respectively. g·K) and Cu- Ideal gas Linear spring
2. A separation column at a temperature of 100C is subjected
for cooling for a certain period of time. If the separation column
is 1500 mm high and 18 cm in diameter, and eventually exposed to an
environment temperature of 35C, determine the following with a
neat diagram:
a) Heat Transfer Coefficient (in J/s m2C and kJ/s m2C)
b) Heat transfer Rate (in W and kW)
Assume the properties of air at mean temperature as density
(ρ) = 1.06 kg/m3,...
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