Engineering, 10.09.2019 00:30 skaterwolf1317
Consider a thin suspended hotplate that measures 0.2 m × 0.2 m. the isothermal plate has a mass of 3.75 kg, a specific heat of 2770 j/kg·k, and a temperature of 275°c. the ambient air temperature is 25°c and the surroundings temperature is 25°c. if the convection coefficient is 6.4 w/m2·k and the emissivity of the plate is ɛ= 0.42, determine the time rate of change of the plate temperature, dt/dt , when the plate temperature is 275°c. evaluate the magnitude of the heat losses by convection and by radiation.
Answers: 3
Engineering, 04.07.2019 18:10
Refrigerant 134a enters an insulated compressor operating at steady state as saturated vapor at -26°c with a volumetric flow rate of 0.18 m3/s. refrigerant exits at 9 bar, 70°c. changes in kinetic and potential energy from inlet to exit can be ignored. determine the volumetric flow rate at the exit, in m3/s, and the compressor power, in kw.
Answers: 1
Engineering, 04.07.2019 18:10
Which of the following refers to refers to how well the control system responds to sudden changes in the system. a)-transient regulation b)- distributed regulation c)-constant regulation d)-steady-state regulation
Answers: 1
Engineering, 04.07.2019 18:20
Athin walled concentric tube exchanger is used to cool engine oil from 160°c to 60°c with water that is available at 25°c acting as a coolant. the oil and water flow rates are each at 2 kg/s, and the diameter of the inner tube is 0.5 m and the corresponding value of the overall heat transfer coefficient is 250 w/m2. oc. how long must the heat exchanger be to accomplish the desired cooling? cpwater=4.187 kj/kg-candcpengine el=2.035 kj/kg·°c, oil . 120]
Answers: 1
Engineering, 04.07.2019 19:10
10 kg of co2 is initially contained at 400 kpa and 300 k. the gas constant for carbon dioxide is 189 j/lkg k) and has a specific heat ratio, k, of 1.289. isentropic expansion then occurs until the pressure is 200 kpa. a) determine the initial volume of co2 in m. b) determine the final temperature in k. c) determine the work done by the system during the expansion kl.
Answers: 2
Consider a thin suspended hotplate that measures 0.2 m × 0.2 m. the isothermal plate has a mass of 3...
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