Air within a piston cylinder assembly executes a Carnot refrigeration cycle between hot and cold reservoirs at TH=600 K and TC=3
00 K, respectively. The magnitude of the heat transfer rejected to the high temperature reservoir is 250 kJ per kg of air. The pressure at the start of the isothermal expansion is 325 kPa. The air can be modeled as an ideal gas with constant specific heat (k=1.4). For the air as a system, determine
a. (5) the coefficient of performance.
b. (5) the net work input to the cycle in kJ/kg.
c. (10) the Pv and Ts diagrams for the cycle with arrows showing the directions of the processes.
You may answer parts (a) and (b) in the response box. Part (c) and your calculations supporting.(a) and (b) must be included in your uploaded response file.
a. (5) the coefficient of performance.
b. (5) the net work input to the cycle in kJ/kg.
c. (10) the Pv and Ts diagrams for the cycle with arrows showing the directions of the processes.
You may answer parts (a) and (b) in the response box. Part (c) and your calculations supporting.(a) and (b) must be included in your uploaded response file.
1 answer:
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Answer:
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The minimum work required for the state to change is
Explanation:
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Answer:
The break force that must be applied to hold the plane stationary is 12597.4 N
Explanation:
p₁ = p₂, T₁ = T₂
The heat supplied = × Heating value of jet fuel
The heat supplied = 0.5 kg/s × 42,700 kJ/kg = 21,350 kJ/s
The heat supplied = ·
= 20 kg/s
The heat supplied = 20* = 21,350 kJ/s
= 1.15 kJ/kg
T₃ = 21,350/(1.15*20) + 485.03 = 1413.3 K
p₂ = p₁ × p₂/p₁ = 95×9 = 855 kPa
p₃ = p₂ = 855 kPa
T₃ - T₄ = T₂ - T₁ = 485.03 - 280.15 = 204.88 K
T₄ = 1413.3 - 204.88 = 1208.42 K
T₅ = 1208.42*(2/2.333) = 1035.94 K
= √(1.333*287.3*1035.94) = 629.87 m/s
The total thrust = ×
= 20*629.87 = 12597.4 N
Therefore;
The break force that must be applied to hold the plane stationary = 12597.4 N.