P Vn
We have a total of 7 unknowns. 3 in state 1, 3 in state 2, and n, the polytrpoic
process exponent.
If given any 5 out of these 7, then the remaining 2 can be found.
For example, if we know T1, P1, V1, n, P2, then we can find V2, and T2
P1
V1
T1
constant
P2
V2
T2
Polytropic process
State 1
n
P
COMPRESSIONQU
ADRANT
Heat OUT
processes
State 2
constant V
Process lines to left of adiabatic
line means negative Q (i.e. heat
OUT), on the right are positive Q
(i.e. heat IN) process
Heat IN
processes
Ignore this quadrant in real
engineering equipments
Clock wise,
n=0,1,k,infinity
Initial
state
point
n=0 const
P
n=1,
const T
Ignore this quadrant in real
engineering equipments
EXPANSION
QUADRANT
Heat IN
processes
Heat OUT
processes
n=k, adiapatic, const S
v
n=k const S
T
n
constant V
n=0,
const P
Ignore this quadrant in real
engineering equipments
Initial
state
point
EXPANSION
QUADRANT
n=1 const
T
COMPRESSIONQU
ADRANT
Ignore this quadrant in real
engineering equipments
Clock wise,
n=0,1,k,infinity
s
Polytrpoic process
by Nasser Abbasi
polytropic.vsd
August 2004