Question

Three kilograms of nitrogen gas at 27 °C, 0.15 MPa are compressed isothermally to 0.3 MPa in a piston-cylinder device. Determine the minimum work of compression, in kJ.

Answer #1

A piston cylinder device contains 0.15 kg of air initially at 2
MPa and 350 C. First, the air expands isothermally to a pressure of
500 kPa. Then, it is compressed polytropically back to the initial
pressure (2 MPa) with a polytropic exponent of 1.2. Find the work
performed or introduced by or to the air for each process. Express
it both times in kJ.

In one stroke of a reciprocating compressor, Nitrogen is
isothermally and reversibly compressed in a piston + cylinder from
298 K and 20 bar to 200 bar. Assume 2 moles of gas are processed
per stroke, and the molecular weight of the Nitrogen is 28 kg/kmol,
compute the heat removal (Q) and work (WEC) required in kJ/kg.

1 mole of a non-ideal gas is compressed isothermally at 100°C
from 1 bar to 50 bar. What are the heat and work needed for this
(reversible) compression if the gas conforms to the principle of
corresponding states?
The critical properties of the non-ideal gas are Tc = 406 K
and Pc = 11.3 MPa.

1) An ideal gas is contained in a
piston-cylinder device and undergoes a power cycle as follows:
1-2 isentropic compression from an initial
temperatureT1= 20 degree celsius with a compression ratio
r = 5
2-3 constant pressure heat addition 3-1 constant volume heat
rejection
The gas has constant specific heats with cv = 0.7
kJ/kg·K and R= 0.3 kJ/kg·K.
(a) Sketch the
P-v and T-s diagrams for the cycle.
(b) Determine the heat
and work interactions for each pro-cess, in...

A cylinder with a piston contains 0.100 mol of nitrogen at
2.00×105 Pa and 320 K . The nitrogen may be treated as
an ideal gas. The gas is first compressed isobarically to half its
original volume. It then expands adiabatically back to its original
volume, and finally it is heated isochorically to its original
pressure.
A) Find the work done by the gas during the initial
compression
B) Find the heat added to the gas during the initial
compression...

Three kilograms of air within a piston-cylinder assembly
executes a Carnot power cycle. The isothermal expansion occurs at
700K from 1.25 bar to 0.85 bar; the air can be treated as an ideal
gas. If the cycle thermal efficiency is 65%,
- determine the temperature of the isothermal compression
- calculate the net work developed for the cycle in kJ
- draw the cycle on both Pv and Ts diagrams, labelling the types of
processes and including arrows to show...

A piston-cylinder device with a set of stops initially contains
0.35 kg of steam at 1.0 MPa and 900 degrees C. The location of the
stops corresponds to 44 percent of the initial volume. Now the
steam is cooled. Determine the magnitude of the compression work if
the final state is (A) 1.0 MPa and 600 degrees C and W=. kJ (B) 500
kPa. W=. kJ (C) Also determine the temperature at the final state
in part (B). T2=. C

In a cylinder/piston arrangement, air is compressed in a
reversible polytropic process to a final state of 800 kPa, 500 K.
Initially air is at 110 kPa and 25oC. During the
compression process heat transfer takes place with the ambient
maintained at 25oC. Assume air as an ideal gas (R =0.287
kJ/kg) and has constant specific heats of Cp = 1.004
kJ/kgK and Cv = 0.717 kJ/kgK. If the mass of air in the
cylinder is 0.1286 kg, determine
a)...

Propane gas at 100 c is compressed isothermally from an initial
pressure of 1 bar to a final pressure of 5 bar.
a. Determine the Delta H of the process
b. Determine the Delta S of the process
c. Comment on the differences between a closed and an open
system undergoing this change in terms of Q,W,H and S.

1-kg water in a frictionless piston-cylinder device is initially
at 250°C and 300 kPa (state
1). A total of 700 kJ of work is done ON the water
in order to isothermally reduce its volume to
1/20 of its initial volume (state 2). Determine the magnitude and
direction of the heat transfer
involved in this process.
Answer: -1147 kJ.

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