Engineering, 08.11.2019 07:31, dlasheab
Athick steel slab (rho = 7800 kg/m , c = 480 j/kg⋅k, k = 50 w/m ⋅ k) is initially at 300°c and is cooled by water jets impinging on one of its surfaces. the temperature of the water is 25°c, and the jets maintain an extremely large, approximately uniform convection coefficient at the surface. assuming that the surface is maintained at the temperature of the water throughout the cooling, how long will it take for the temperature to reach 50°c at a distance of 25 mm from the surface?
Answers: 2
Engineering, 04.07.2019 18:10, viicborella
Steel is coated with a thin layer of ceramic to protect against corrosion. what do you expect to happen to the coating when the temperature of the steel is increased significantly? explain.
Answers: 1
Engineering, 04.07.2019 18:10, abdirahmansoloman
Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?
Answers: 1
Engineering, 04.07.2019 18:10, 0436500
Aturning operation is performed with following conditions: rake angle of 12°, a feed of 0.35 mm/rev, and a depth of cut of 1.1 mm. the work piece is aluminum alloy 6061 with t6 heat treatment (a16061-t6). the resultant chip thickness was measured to be 1.0 mm. estimate the cutting force, fc. use shear stress of 207 mpa and coefficient of friction on the tool face of 0.6.
Answers: 1
Athick steel slab (rho = 7800 kg/m , c = 480 j/kg⋅k, k = 50 w/m ⋅ k) is initially at 300°c and is co...
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