Entropy Vanation 2.4.7.2
dq-Sw+de
Tas = pdr + du
ds = Fav + = ar + a(u=1/2) (7/2)= dr-÷a (pr) + (u+Pr) of dr+ = dr+ d(u+Plp)
=÷(par-d(pv))+Cp+ = =[par-par-rap] + Cp
pv=RT= ds=-dp+Cpz-s,=Cpin ()-Rin()
TEST NEXT WED (problems will be put online) updated notes
If Isentropic:
const
and finally
r=const
Ex 2.4.3: Tp.
(a) 45=0
FIND T
ha 22
RY
(b) 4570
(a) Know Ti and s, so state one is covered (tables) Find T
(b) AS = Rin[(/)]
e R= =
AS
Ex 2.4.4 T = 288 K
P=1.01337 bar
Cp-1.004
8-1.4
R= 0.287
Spor 6.6608 kg.k Looking at Tables...
T2
Sz-S, Cp in Rin 11 P but T₂=T, So.....
1.0/337
PROBLEMS
P-1.01387 bar
P=Ibar
Sp=
S, Spez-Rin 1.01337
Keep all four digits for entropy
(1) Turbofan
Tc-300K
BPR-8-
CV
pic
MH
TH=900K
Draw CV
Mass Conservation (steady flow)
Energy Conservation.
At<<0 <
is more significant
p(h+2+92) vñdo
0=-mche-mahn mm hm BPRhc+hn (BPR)hm
BPR BPR+, Tc +
BPR+1 = W, Tc + W₂ Th
and w, + W₂ = 1