Metal bearings with diameter of 10 mm are initially at equilibrium at 400?C in a furnace....
Metal bearings with diameter of 10 mm are initially at equilibrium at 400?C in a furnace. At t = 0 the bearings are removed from the furnace and cooled slowly in air with h = 150 W/m2K and temperature of 20?C to control the mechanical properties of the metal. Calculate the time required for the center of the sphere to reach a temperature of 335?C. Thermophysical properties are ? = 3000 kg/m3 , k = 20 W/m·K, and c = 1000 J/kg·K.
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Metal bearings with diameter of 10 mm are initially at
equilibrium at 400?C in a furnace....
7. (20 pts) A sphere with 30 mm in diameter initially at 800 K is quenched...
7. (20 pts) A sphere with 30 mm in diameter initially at 800 K is quenched in a large bath having a constant temperature of 320 K with a convection heat transfer of 75 W/m2.K. The thermophysical properties of the sphere material are: p=400 kg/mº, c=1600 J/kg-K, and k=1.7 W/mK. (Use characteristic length Lc=VIA to determine applicability of lumped method; Use radius of the sphere for one term approximation) a) Calculate the time required for the surface of the sphere...
Steel balls 12 mm in diameter are annealed by heating to 1100 K and then slowly...
Steel balls 12 mm in diameter are annealed by heating to 1100 K
and then slowly cooling to 390 K in an air environment for which
?T?= 325 K and h= 20 W/m2·K. Assuming the properties of
the steel to be k= 40 W/m·K, ?= 7800 kg/m3, and c= 600
J/kg·K, estimate the time required for the cooling process.
Problem 5.007 Your answer is incorrect. Try again. Steel balls 12 mm iri diameter are annealed by heatin time required for...
2. A nuclear fuel rod with diameter of D=40 mm and length L=1m, has properties of...
2. A nuclear fuel rod with diameter of D=40 mm and length L=1m, has properties of k=1 W/mK, c=1600J/kg.K, and p=400 kg/m3. (a)Heat is generated uniformly in the rod with q'"' = 2 x 106 W/m3. The rod is first cooled in oil with constant temperature To= 400 K and average heat transfer coefficient h=50 W/m2K. Under steady state, determine the surface temperature of the rod Ts. (10 pts) (b)Now the heat generation in the rod is stopped, where q'''...
Problem 2: A hot metal ball 0.00245 W/m°C; α-0151* 10-s m2/s; d 18 cm) initially at...
Problem 2: A hot metal ball 0.00245 W/m°C; α-0151* 10-s m2/s; d 18 cm) initially at a unifom temperature of 310°C is cooled by placing it in air at 29 C is flowing at a constant 4 m/s. In order to continue on in the manufacturing process, the temperature at the center of the ball must be 70°C. (μ. = 1.872*10-5 kg m-s). The air You mav assume that the properties of air may bem odeled as V = 1.608...
2. A nuclear fuel rod with diameter of D=40 mm and length L=1m, has properties of...
2. A nuclear fuel rod with diameter of D=40 mm and length L=1m, has properties of k=1 W/mK, c=1600J/kg-K, and p=400 kg/m² (a)Heat is generated uniformly in the rod with q'"' = 2 x 106 W/m. The rod is first cooled in oil with constant temperature To= 400 K and average heat transfer coefficient h=50 W/m2K. Under steady state, determine the surface temperature of the rod Ts. (10 pts) (b)Now the heat generation in the rod is stopped, where q"'...
2. A nuclear fuel rod with diameter of D=40 mm and length L=1m, has properties of...
2. A nuclear fuel rod with diameter of D=40 mm and length L=1m, has properties of k=1 W/mK, c=1600J/kg-K, and p=400 kg/m² (a)Heat is generated uniformly in the rod with q'"' = 2 x 106 W/m. The rod is first cooled in oil with constant temperature To= 400 K and average heat transfer coefficient h=50 W/m2K. Under steady state, determine the surface temperature of the rod Ts. (10 pts) (b)Now the heat generation in the rod is stopped, where q"'...
A rod of diameter D = 25 mm and thermal conductivity of 60 W/m K protrudes from a furnace with a wall temperature of 200°C.
A rod of diameter D = 25 mm and thermal conductivity of 60 W/m K protrudes from a furnace with a wall temperature of 200°C. The rod is welded to the furnace wall and is used as a hangar for instrumentation cables. To avoid damaging the cables, the surface temperature of last 100 mm of the rod must be kept below 100°C. The ambient air temperature is 25°C and the convection coefficient is 15 W/m2K. (a) Write the finite-difference equation for...
A nuclear fuel rod with diameter of D=40 mm and length L=1m, has properties of k=1...
A nuclear fuel rod with diameter of D=40 mm and length L=1m, has properties of k=1 W/ mK, c=1600J/kg.K, and p=400 kg/mº. (a)Heat is generated uniformly in the rod with q'"' = 2 x 10 W/m. The rod is first cooled in oil with constant temperature Tu= 400 K and average heat transfer coefficient h=50 W/m2K. Under steady state, determine the surface temperature of the rod Ts. (10 pts) (b)Now the heat generation in the rod is stopped, where q'"'...
Q3. A very long horizontal cylinder of Unobtainium, of diameter 100 mm, is initially at a...
Q3. A very long horizontal cylinder of Unobtainium, of diameter 100 mm, is initially at a uniform temperature of 500 K. The cylinder is cooled by a fan. The fan blow airs, with a temperature of 300 K, over the cylinder at a velocity of 6 m/s in a direction perpendicular to the axis of the cylinder. Calculate a) the average convective heat transfer coefficient at the beginning of the cooling process when the initial temperature of the cylinder is...
Problem 7.036 A long, cylindrical, electrical heating element of diameter D = 10 mm, termal conductivity...
Problem 7.036 A long, cylindrical, electrical heating element of diameter D = 10 mm, termal conductivity k = 240 w/m·K, density ρ = 2700 kg/m3, and specific heat cp-900 נ/kg-K is installed in a duct for which air moves in cross flow over the heater at a temperature and velocity of 27°C and 20 m/s, respectively (a) Neglecting radiation, estimate the steady-state surface temperature when, per unit length of the heater, electrical energy is being dissipated at a rate of...
7. (20 pts) A sphere with 30 mm in diameter initially at 800 K is quenched in a large bath having a constant temperature of 320 K with a convection heat transfer of 75 W/m2.K. The thermophysical properties of the sphere material are: p=400 kg/mº, c=1600 J/kg-K, and k=1.7 W/mK. (Use characteristic length Lc=VIA to determine applicability of lumped method; Use radius of the sphere for one term approximation) a) Calculate the time required for the surface of the sphere...
Steel balls 12 mm in diameter are annealed by heating to 1100 K
and then slowly cooling to 390 K in an air environment for which
?T?= 325 K and h= 20 W/m2·K. Assuming the properties of
the steel to be k= 40 W/m·K, ?= 7800 kg/m3, and c= 600
J/kg·K, estimate the time required for the cooling process.
Problem 5.007 Your answer is incorrect. Try again. Steel balls 12 mm iri diameter are annealed by heatin time required for...
2. A nuclear fuel rod with diameter of D=40 mm and length L=1m, has properties of k=1 W/mK, c=1600J/kg.K, and p=400 kg/m3. (a)Heat is generated uniformly in the rod with q'"' = 2 x 106 W/m3. The rod is first cooled in oil with constant temperature To= 400 K and average heat transfer coefficient h=50 W/m2K. Under steady state, determine the surface temperature of the rod Ts. (10 pts) (b)Now the heat generation in the rod is stopped, where q'''...
Problem 2: A hot metal ball 0.00245 W/m°C; α-0151* 10-s m2/s; d 18 cm) initially at a unifom temperature of 310°C is cooled by placing it in air at 29 C is flowing at a constant 4 m/s. In order to continue on in the manufacturing process, the temperature at the center of the ball must be 70°C. (μ. = 1.872*10-5 kg m-s). The air You mav assume that the properties of air may bem odeled as V = 1.608...
2. A nuclear fuel rod with diameter of D=40 mm and length L=1m, has properties of k=1 W/mK, c=1600J/kg-K, and p=400 kg/m² (a)Heat is generated uniformly in the rod with q'"' = 2 x 106 W/m. The rod is first cooled in oil with constant temperature To= 400 K and average heat transfer coefficient h=50 W/m2K. Under steady state, determine the surface temperature of the rod Ts. (10 pts) (b)Now the heat generation in the rod is stopped, where q"'...
2. A nuclear fuel rod with diameter of D=40 mm and length L=1m, has properties of k=1 W/mK, c=1600J/kg-K, and p=400 kg/m² (a)Heat is generated uniformly in the rod with q'"' = 2 x 106 W/m. The rod is first cooled in oil with constant temperature To= 400 K and average heat transfer coefficient h=50 W/m2K. Under steady state, determine the surface temperature of the rod Ts. (10 pts) (b)Now the heat generation in the rod is stopped, where q"'...
A nuclear fuel rod with diameter of D=40 mm and length L=1m, has properties of k=1 W/ mK, c=1600J/kg.K, and p=400 kg/mº. (a)Heat is generated uniformly in the rod with q'"' = 2 x 10 W/m. The rod is first cooled in oil with constant temperature Tu= 400 K and average heat transfer coefficient h=50 W/m2K. Under steady state, determine the surface temperature of the rod Ts. (10 pts) (b)Now the heat generation in the rod is stopped, where q'"'...
Q3. A very long horizontal cylinder of Unobtainium, of diameter 100 mm, is initially at a uniform temperature of 500 K. The cylinder is cooled by a fan. The fan blow airs, with a temperature of 300 K, over the cylinder at a velocity of 6 m/s in a direction perpendicular to the axis of the cylinder. Calculate a) the average convective heat transfer coefficient at the beginning of the cooling process when the initial temperature of the cylinder is...
Problem 7.036 A long, cylindrical, electrical heating element of diameter D = 10 mm, termal conductivity k = 240 w/m·K, density ρ = 2700 kg/m3, and specific heat cp-900 נ/kg-K is installed in a duct for which air moves in cross flow over the heater at a temperature and velocity of 27°C and 20 m/s, respectively (a) Neglecting radiation, estimate the steady-state surface temperature when, per unit length of the heater, electrical energy is being dissipated at a rate of...
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