Air temperature, T=20C is caused to flow at V = 1 m/s over the surface of an electrically heated ...
Air temperature, T=20C is caused to flow at V = 1 m/s over the surface of an electrically heated horizontal cylinder, D = 2 cm in diameter. The temperature of the surface of the cylinder under these conditions, Ts= 100C. Determine the temperature Ts' that the surface of the cylinder would attain after steady state conditions had been reestablished if the blower were to stop causing the air flow to cease, assuming that the heat generation remained constant.
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Air temperature, T=20C is caused to flow at V = 1 m/s over the surface of an electrically heated ...
Problem 3: (35pts) Atmospheric air enters the heated section of a circular tube at a flow...
Problem 3: (35pts) Atmospheric air enters the heated section of a circular tube at a flow rate of 0.005 kg/s and a temperature of 30°C. The tube is of diameter D =60mm, and fully developed conditions with h = 30W/m2K exist over the entire length of L-4m. Take cp-1015 /kg.K 2 (a) (10pts) For the case of uniform surface heat flux at q"-1000W/m, determine the total heat transfer rate q and the mean temperature of the air leaving the tube...
8) Air flows over a flat plate at a velocity of 20 m/s and a temperature...
8) Air flows over a flat plate at a velocity of 20 m/s and a temperature of 20C. The surface temperature of the plate is 134C, and the length of the plate in the direction of flow is 1.5 m. Properties of air may be taken as A-0.030 W/m-C, Pr-0.700, and a/p 2.092E-5 m/s (5% ) What is the location from the leading edge, X, where the flow becomes turbulent Re (20)15 a l Ve30s T20 T LaLS 523 m...
8.12 Dry, compressed air at Tm.i75°C, p-10 atm, with a mass flow rate of 0.001 kg/s,...
8.12 Dry, compressed air at Tm.i75°C, p-10 atm, with a mass flow rate of 0.001 kg/s, enters a 30-mm-diameter, 5-m-long tube whose surface is at Ts - 25°C. (a) Determine the thermal entry length, the mean temperature of the air at the tube outlet, the rate of heat transfer from the air to the tube wall, and the power required to flow the air through the tube. For these conditions the fully developed heat transfer coefficient is h- 3.58 W/m2...
Question 3 (40 marks) (a) Air enters a horizontal nozzle with a velocity of 1 m/s,...
Question 3 (40 marks) (a) Air enters a horizontal nozzle with a velocity of 1 m/s, a pressure of 2 bar and a temperature of 350 K. At exit from nozzle, the air temperature is 450 K. The combined rate of specific heat transfers, and specific work transfers, w to the air as it passes through the nozzle is 150 kJ/kg. Assume that the air flow is steady and air can be treated as perfect gas with = 1005 J/(kg.K)....
Air at 20°C and 1 atm flows over a long cylinder at 1 m/s. The cylinder...
Air at 20°C and 1 atm flows over a long cylinder at 1 m/s. The cylinder has a diameter of 10mm and its initial temperature is 134°C. If the density, specific heat, and 3 conductivity of the cylinder are 7832 kg/m , 549 J/kg.K, and 49.2 W/m.K, respectively, calculate the temperature on surface of the cylinder after 100 seconds.
heat and mass transfer (20 points) Air at 25°C cools a 2170 cylindrical battery (with a diameter of 21 mm and a length of 70 mm) with a cross flow velocity of 6 m/s. a) Determine the average conv...
heat and mass transfer
(20 points) Air at 25°C cools a 2170 cylindrical battery (with a diameter of 21 mm and a length of 70 mm) with a cross flow velocity of 6 m/s. a) Determine the average convective heat transfer coefficient. (b) If the battery's internal heat generation is 5W and its thermal conductivity is 0.6 w/m-k, the determine the battery surface temperature and the maximum temperature in battery
(20 points) Air at 25°C cools a 2170 cylindrical battery...
1. Water flows over a cylinder perpendicular to its axis (in cross flow) at 3 m/s....
1. Water flows over a cylinder perpendicular to its axis (in cross flow) at 3 m/s. The water is at 300 K and the cylinder surface is at 350 K. The cylinder diameter is 50 mm. 1. Identify the characteristic length 2. The temperature at which properties must be evaluated 3. Calculate the Reynolds number 4. Identify the Nusselt correlations for this problem 5. Calculate the average convective heat transfer coefficient
7.34 Consider the following fluids, each with a velocity of V- 3 m/s and a temperature of T 20°C,...
7.34 Consider the following fluids, each with a velocity of V- 3 m/s and a temperature of T 20°C, in cross flow over a 10-mm-diameter cylinder maintained at 50°C: atmospheric air, saturated water, and engine oil. (a) Calculate the rate of heat transfer per unit length, q, using the Churchill-Bernstein correlation. (b) Generate a plot ofq as a function of fluid velocity for o.5 s Vs 10 m/s.
7.34 Consider the following fluids, each with a velocity of V- 3...
Wind is blowing at 5 km/h over a building wall of size 5 mx10 m. Air temperature is 0°C and wall 1) surface is at 1...
Wind is blowing at 5 km/h over a building wall of size 5 mx10 m. Air temperature is 0°C and wall 1) surface is at 10°C. 1) Calculate the avg. heat transfer coefficient along the 10 m width of the wall. 2) Calculate the local heat transfer coefficient at a location 10 cm from the leading edge of the wall. (25pts)
Wind is blowing at 5 km/h over a building wall of size 5 mx10 m. Air temperature is 0°C...
Two large parallel plates with surface conditions approximating those of a blackbody are maintained at 800°C...
Two large parallel plates with surface conditions approximating those of a blackbody are maintained at 800°C and 100°C, respectively. Determine the rate of heal transfer by radiation between the plates in Wim and the radiative heat transfer coefficient in W/m K ) 12 Write down the one-dimensional sent heal conduction equation for a plane wall with constant thermal conductivity and heat generation in its simplest form, and indicate what each variable represents 13 Write down the one-dimensional transient heat conduction...
Problem 3: (35pts) Atmospheric air enters the heated section of a circular tube at a flow rate of 0.005 kg/s and a temperature of 30°C. The tube is of diameter D =60mm, and fully developed conditions with h = 30W/m2K exist over the entire length of L-4m. Take cp-1015 /kg.K 2 (a) (10pts) For the case of uniform surface heat flux at q"-1000W/m, determine the total heat transfer rate q and the mean temperature of the air leaving the tube...
8) Air flows over a flat plate at a velocity of 20 m/s and a temperature of 20C. The surface temperature of the plate is 134C, and the length of the plate in the direction of flow is 1.5 m. Properties of air may be taken as A-0.030 W/m-C, Pr-0.700, and a/p 2.092E-5 m/s (5% ) What is the location from the leading edge, X, where the flow becomes turbulent Re (20)15 a l Ve30s T20 T LaLS 523 m...
8.12 Dry, compressed air at Tm.i75°C, p-10 atm, with a mass flow rate of 0.001 kg/s, enters a 30-mm-diameter, 5-m-long tube whose surface is at Ts - 25°C. (a) Determine the thermal entry length, the mean temperature of the air at the tube outlet, the rate of heat transfer from the air to the tube wall, and the power required to flow the air through the tube. For these conditions the fully developed heat transfer coefficient is h- 3.58 W/m2...
Question 3 (40 marks) (a) Air enters a horizontal nozzle with a velocity of 1 m/s, a pressure of 2 bar and a temperature of 350 K. At exit from nozzle, the air temperature is 450 K. The combined rate of specific heat transfers, and specific work transfers, w to the air as it passes through the nozzle is 150 kJ/kg. Assume that the air flow is steady and air can be treated as perfect gas with = 1005 J/(kg.K)....
heat and mass transfer
(20 points) Air at 25°C cools a 2170 cylindrical battery (with a diameter of 21 mm and a length of 70 mm) with a cross flow velocity of 6 m/s. a) Determine the average convective heat transfer coefficient. (b) If the battery's internal heat generation is 5W and its thermal conductivity is 0.6 w/m-k, the determine the battery surface temperature and the maximum temperature in battery
(20 points) Air at 25°C cools a 2170 cylindrical battery...
1. Water flows over a cylinder perpendicular to its axis (in cross flow) at 3 m/s. The water is at 300 K and the cylinder surface is at 350 K. The cylinder diameter is 50 mm. 1. Identify the characteristic length 2. The temperature at which properties must be evaluated 3. Calculate the Reynolds number 4. Identify the Nusselt correlations for this problem 5. Calculate the average convective heat transfer coefficient
7.34 Consider the following fluids, each with a velocity of V- 3 m/s and a temperature of T 20°C, in cross flow over a 10-mm-diameter cylinder maintained at 50°C: atmospheric air, saturated water, and engine oil. (a) Calculate the rate of heat transfer per unit length, q, using the Churchill-Bernstein correlation. (b) Generate a plot ofq as a function of fluid velocity for o.5 s Vs 10 m/s.
7.34 Consider the following fluids, each with a velocity of V- 3...
Wind is blowing at 5 km/h over a building wall of size 5 mx10 m. Air temperature is 0°C and wall 1) surface is at 10°C. 1) Calculate the avg. heat transfer coefficient along the 10 m width of the wall. 2) Calculate the local heat transfer coefficient at a location 10 cm from the leading edge of the wall. (25pts)
Wind is blowing at 5 km/h over a building wall of size 5 mx10 m. Air temperature is 0°C...
Two large parallel plates with surface conditions approximating those of a blackbody are maintained at 800°C and 100°C, respectively. Determine the rate of heal transfer by radiation between the plates in Wim and the radiative heat transfer coefficient in W/m K ) 12 Write down the one-dimensional sent heal conduction equation for a plane wall with constant thermal conductivity and heat generation in its simplest form, and indicate what each variable represents 13 Write down the one-dimensional transient heat conduction...
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