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Still water of some depth initially at 37°C has its surface raised to 100°C (6 and...
2. As the sun rises, the temperature at the surface of a lake is quickly raised and maintained at 290K. The lake was originally 280K throughout. The thermal diffusivity of water is 0.143 10-6 m2/s. H...
2. As the sun rises, the temperature at the surface of a lake is quickly raised and maintained at 290K. The lake was originally 280K throughout. The thermal diffusivity of water is 0.143 10-6 m2/s. How long will it take for water 5 cm below the surface to rise to 285 K.
2. As the sun rises, the temperature at the surface of a lake is quickly raised and maintained at 290K. The lake was originally 280K throughout. The thermal...
As the sun rises, the temperature at the surface of a lake is quickly raised and...
As the sun rises, the temperature at the surface of a lake is quickly raised and maintained at 290K. The lake was originally 280K throughout. The thermal diffusivity of water is 0.143 × 10−6 m2/s. How long will it take for water 5 cm below the surface to rise to 285K.
The upper surface of a 60-cm-thick solid plate (k = 237 W/m.K) is being cooled by...
The upper surface of a 60-cm-thick solid plate (k = 237 W/m.K) is being cooled by water with temperature of 20°C. The upper and lower surfaces of the solid plate maintained at constant temperatures of 60°C and 120°C, respectively. Given: The thermal conductivity of the solid plate is given as k = 237 W/ mK. (T..+) The thermal conductivity of water at the film temperature of T, = =(60°C + 20°C)/2 = 40°C is kfluid = 0.631 W/mK. 1. value...
1 answer & continue > The upper surface of a 60-cm-thick solid plate (k = 237...
1 answer & continue > The upper surface of a 60-cm-thick solid plate (k = 237 W/m-K) is being cooled by water with temperature of 20°C. The upper and lower surfaces of the solid plate maintained at constant temperatures of 60°C and 120°C, respectively. Given: The thermal conductivity of the solid plate is given as k = 237 W/mK. The thermal conductivity of water at the film temperature of T; = (1,1770) =(60°C + 20°C)/2 = 40°C is kfluid =...
On a summer day, the air temperature is 36°C and the relative humidity is 20%. Water...
On a summer day, the air temperature is 36°C and the relative humidity is 20%. Water evaporates from the surface of a lake at a rate of 0.20 kg/h per square metre of water surface area. The temperature of water is 25°C. (a) Determine the mass transfer coefficient. (10 marks) (b) Determine the convective heat transfer coefficient. (10 marks) (c) Determine the net heat loss (in W/m2) from the lake. (5 marks) The specific volume of water vapour at 25°C...
A liquid has its temperature raised from 15°C to 65°C by passing it through a heater...
A liquid has its temperature raised from 15°C to 65°C by passing it through a heater in which the heating surface is maintained at 125°C by condensing steam. If the overall coefficient of heat transfer can be assumed to vary as the velocity raised to the power 0.8, what will be the exit temperature of the liquid if its velocity is doubled? Assume liquid thermal properties are temperature-independent over the range concerned. [ans. 60.15 C]
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...
Consider two-dimensional, steady-state conduction in a square cross section with prescribed surfa...
need help with c and d
Consider two-dimensional, steady-state conduction in a square cross section with prescribed surface temperatures shown in the figure. 2) 100°C a) Determine the temperatures at nodes 1, 2, 3, and 4 Estimate the midpoint temperature. Reducing the mesh size by a factor of 2, determine the corresponding nodal temperatures. Compare your results with those from the coarser grid. b) 50°C 200°c c) If the body generates heat at a rate of 20,000 W/m determine the...
Day 7 Non-text: Ethanol is maintained at its boiling point (78.4°C) in a spherical container with...
Day 7 Non-text: Ethanol is maintained at its boiling point (78.4°C) in a spherical container with an inner radius of 48 cm and an outer radius of 57 cm and a thermal conductivity of 1.2 W/ mK. Heating wire wrapped around the outer surface of the container provides a uniform heat flux of 1,075 W/m2. Assuming the inner surface of the container is at the same temperature as the ethanol, develop an expression for the temperature profile (as a function...
3. The annular pipe arrangement shown in the figure below is made of stainless steel and the oute...
3. The annular pipe arrangement shown in the figure below is made of stainless steel and the outer surface is insulated. Air flows through the central pipe with a mass flow rate, ma0.026 kg/s. Water flows through the annular region with a mass flow rate, mw-0.58 kg/s. At the given position along the pipe the bulk temperature of the air, Ta-100°C, and the bulk temperature of the water, Tw- s 10°C. The thermal conductivity of stainless steel, kss 15 W/mK....
2. As the sun rises, the temperature at the surface of a lake is quickly raised and maintained at 290K. The lake was originally 280K throughout. The thermal diffusivity of water is 0.143 10-6 m2/s. How long will it take for water 5 cm below the surface to rise to 285 K.
2. As the sun rises, the temperature at the surface of a lake is quickly raised and maintained at 290K. The lake was originally 280K throughout. The thermal...
The upper surface of a 60-cm-thick solid plate (k = 237 W/m.K) is being cooled by water with temperature of 20°C. The upper and lower surfaces of the solid plate maintained at constant temperatures of 60°C and 120°C, respectively. Given: The thermal conductivity of the solid plate is given as k = 237 W/ mK. (T..+) The thermal conductivity of water at the film temperature of T, = =(60°C + 20°C)/2 = 40°C is kfluid = 0.631 W/mK. 1. value...
1 answer & continue > The upper surface of a 60-cm-thick solid plate (k = 237 W/m-K) is being cooled by water with temperature of 20°C. The upper and lower surfaces of the solid plate maintained at constant temperatures of 60°C and 120°C, respectively. Given: The thermal conductivity of the solid plate is given as k = 237 W/mK. The thermal conductivity of water at the film temperature of T; = (1,1770) =(60°C + 20°C)/2 = 40°C is kfluid =...
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...
need help with c and d
Consider two-dimensional, steady-state conduction in a square cross section with prescribed surface temperatures shown in the figure. 2) 100°C a) Determine the temperatures at nodes 1, 2, 3, and 4 Estimate the midpoint temperature. Reducing the mesh size by a factor of 2, determine the corresponding nodal temperatures. Compare your results with those from the coarser grid. b) 50°C 200°c c) If the body generates heat at a rate of 20,000 W/m determine the...
Day 7 Non-text: Ethanol is maintained at its boiling point (78.4°C) in a spherical container with an inner radius of 48 cm and an outer radius of 57 cm and a thermal conductivity of 1.2 W/ mK. Heating wire wrapped around the outer surface of the container provides a uniform heat flux of 1,075 W/m2. Assuming the inner surface of the container is at the same temperature as the ethanol, develop an expression for the temperature profile (as a function...
3. The annular pipe arrangement shown in the figure below is made of stainless steel and the outer surface is insulated. Air flows through the central pipe with a mass flow rate, ma0.026 kg/s. Water flows through the annular region with a mass flow rate, mw-0.58 kg/s. At the given position along the pipe the bulk temperature of the air, Ta-100°C, and the bulk temperature of the water, Tw- s 10°C. The thermal conductivity of stainless steel, kss 15 W/mK....
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