• Question Tag: heat and mass transfer
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• ## Two large diffuse gray parallel plates, separated by a small distance, have surface temperature of 400 K and 300 K. If the emmissivities of the surface are 0.8 and the Stefan-Boltzmann constant is 5.67 x 10^-8 W/m3K4, What is the net radiation heat exchange rate in KW/m3 between the two plates?

Two large diffuse gray parallel plates, separated by a small distance, have surface temperature of 400 K and 300 K. …

Mech_59 Asked on 16th October 2023 in
• 319 views
• ## Two concentric spheres of diameters D1 = 0.5 m and D2 = 1 m are separated by an air space as shown in given figure and have surface temperatures of 400 K and 300 K respectively.

Two concentric spheres of diameters D1 = 0.5 m and D2 = 1 m are separated by an air space …

Mech_59 Asked on 13th October 2023 in
• 327 views
• ## Consider a hot, boiled egg in a spacecraft that is filled with air at atmospheric presssure and temperature at all times.

Consider a hot, boiled egg in a spacecraft that is filled with air at atmospheric presssure and temperature at all …

Mech_59 Asked on 13th October 2023 in
• 344 views
• ## Air at 27°C and 1 atm flows over a flat plate at velocity of 2 m/s. Assume that the plate is heated over its entire lenght to a temperature of 60°C.

Air at 27°C and 1 atm flows over a flat plate at velocity of 2 m/s. Assume that the plate …

Mech_59 Asked on 12th October 2023 in
• 306 views
• ## A fluid flowing over a flat plate has the following properties : dynamic viscosity = 25 x 10^-6 kg/ms, specific heat = 2.0 kJ/kgK, thermal conductivity 0.05 W/mK.

A fluid flowing over a flat plate has the following properties : dynamic viscosity = 25 x 10^-6 kg/ms, specific …

Mech_59 Asked on 12th October 2023 in
• 320 views
• ## An aluminium sphere weighning 5.5 kg and initially at a temperature of 290°C is suddenly immersed in a fluid at 15°C. The convective heat transfer coefficient is 58 W/m²K.

An aluminium sphere weighning 5.5 kg and initially at a temperature of 290°C is suddenly immersed in a fluid at …

Mech_59 Asked on 29th September 2023 in
• 620 views
• ## A metallic rod (k  = 32 W/m°C), 10 mm in diameter and 80 mm long, with an insulated end is to be used as spine. It is expossed to sourrounding with a temperature of 80°C and a heat transfer coefficient 55 W/m²°C.

A metallic rod (k  = 32 W/m°C), 10 mm in diameter and 80 mm long,  with an insulated end is …

Mech_59 Asked on 29th September 2023 in
• 309 views
• ## What is the efficciency of a plate fin of length L = 1.5 cm and thickness 2 mm, (if k = 210 W/m-K, h = 285 W/m²k).

What is the efficciency of a plate fin of length L = 1.5 cm and thickness 2 mm, (if k …

Mech_59 Asked on 28th September 2023 in
• 1K views
• ## It is required to heat oil to about 500°C for quenching purpose. A ladder is used in the furnace. The section of ladder is (10 x 20) mm². The sourroundings are at 27°C.

It is required to heat oil to about 500°C for quenching purpose. A ladder is used in the furnace. The …

Mech_59 Asked on 28th September 2023 in
• 2K views