Engineering, 05.05.2020 20:28 Twitches
A two-stage cascade refrigeration system is to provide cooling at -40ºC while operating with the high-temperature condenser at 1.6 MPa. Each stage operates on the ideal vapor-compression refrigeration cycle. The upper vapor compression refrigeration system uses water as its working fluid and operates its evaporator at 5ºC. The lower cycle uses refrigerant-134a as its working fluid and operates its condenser at 400 kPa. This system produces a cooling effect at 20 kJ/s. Determine (a) The heat transfer rate within the heat exchanger connecting the two refrigeration systems. (b) The mass flow rate of R-134a and water in their respective cycles, and (c) The required heat transfer area A inside the heat exchanger if the overall heat transfer coefficient U is 25 W/m2K . (25 pt.)
Answers: 1
Engineering, 04.07.2019 19:10
What are the major differences between injection molding and extrusion?
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Engineering, 04.07.2019 19:10
Afoot bridge is made as a simple deck, 4 m long, with a cross section 2 m (wide) and 20 cm thick, and made of wood. the deck is supported at the two ends. the maximum load allowable on the bridge is 10 tons, provided it is uniformly distributed on the deck. to sense this load, a strain gauge is placed at the center of the bridge and its resistance is monitored. if the sensor has a nominal resistance of 350 s2 and a gauge factor of 3.6, what is the reading of the strain gauge at maximum load? the modulus of elasticity for the wood used in the construction is 10 gpa.
Answers: 2
Engineering, 06.07.2019 03:20
Areaction-bonded silicon nitride ceramic has a strength of 250 mpa and a fracture toughness of 3.4 mpa(m)^1/2, what is the largest-sized internal flaw that this material can support without fracturing? (use y -1 in the fracture-toughness equation.)
Answers: 3
Engineering, 06.07.2019 03:20
Aparticle moves along a straight line such that its acceleration is a=(4t^2-2) m/s, where t is in seconds. when t = 0, the particle is located 2 m to the left of the origin, and when t = 2, it is 20 m to the left of the origin. determine the position of the particle when t=4s.
Answers: 1
A two-stage cascade refrigeration system is to provide cooling at -40ºC while operating with the hig...
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