Two streams of air enter a control volume: stream 1 enters at a rate of 0.05 kg / s at 300 kPa and 380 K, while stream 2 enters
at 400 kPa and 300 K. Stream 3 leaves the control volume at 150 kPa and 270 K. The control volume does 3 kW of work on the surroundings while losing 5 kW of heat. Find the mass flow rate of stream 2. Neglect changes in kinetic and potential energy.
1 answer:
Answer:
0.08kg/s
Explanation:
For this problem you must use 2 equations, the first is the continuity equation that indicates that all the mass flows that enter is equal to those that leave the system, there you have the first equation.
The second equation is obtained using the first law of thermodynamics that indicates that all the energies that enter a system are the same that come out, you must take into account the heat flows, work and mass flows of each state, as well as their enthalpies found with the temperature.
finally you use the two previous equations to make a system and find the mass flows
I attached procedure
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Answer:
The energy yield for one gallon of ethanol is 2.473 %.
Explanation:
The net energy yield (), expressed in percentage for one gallon of ethanol is the percentage of the ratio of the difference of the provided energy (
), measured in Btu, and the energy needed to produce the ethanol (
), measured in Btu, divided by the energy needed to produce the ethanol. That is:
(1)
If we know that and
, then the net energy yield of 1 gallon of ethanol:
The energy yield for one gallon of ethanol is 2.473 %.
Answer:
t = 59.37 s
Explanation:
Given data:
thermal diffusivity
theraml conductivity = k = 22 W/m.K
h = 300 W/ m^2.K
= 25 degree C = 298 k
= 60 degree C = 333 k
= 75 degree C = 348 L
diameter d = 0.1 m
characteristics length Lc = r/3 = = 0.0166
at Bi = 0.226
Ai = 0.982
-1.187 = - 0.02t
t = 59.37 s