Setul 1 de Probleme Obligatorii
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Transcript of Setul 1 de Probleme Obligatorii
DRAGANECI DENISA
TIRTAU MIHAI - SORINGrupa 2205 BN=11
TEMA 1
1. pa=752 mmHg;
a).pm=(1,5n+0,5)bar=17 bar
pa=752 mmHg=752/750=1,0026bar
p=pa+pm=18,0026bar pm=17bar=17*105Pa
pa=1,0026*105Pa
p=18,0026*105Pa
pm=17*750=12750mmHg
pa=752mmHg
p=13502mmHgpm==17,329*104mmH2Opa==1,0224*104mmH2O
p=18,3514*104mmH2O
pm==17,329 kgf/cm2
pa==1,0224kgf/cm2
p=18,3514kgf/cm2b).pv=(755-4n)mmHg=711mmHg;pa=752mmHg;p=pa-pv
pv==0,948bar
pa=1,0026bar
p=0,0546bar
pv==0,948*105Pa
pa=1,0026*105Pap=0,0546*105Pa
p=41mmHg
pv =0,966*104mmH2O
pa==1,0224*104mmH2Op=0,0564*104mmH2O
pv==0,966kgf/cm2
pa==1,0224khf/cm2p=0,0564kgf/cm2
2.Dm=(100-2n)t/h=78t/h; p1=11bar; t1=(100+40ln11)C=195,9C=469,05K; p2=(50+3*11)bar=83bar;=1000kg/m3;c=4,18+0,002t kJ/kg*K
Fluid incompresibil=>v=cta).lt,12=v(p1-p2)p= m = Dm
v=
lt,12=Pa=-72*102J
p==156*103Wb).h1=cvt1=(4,18+0,002t)*469,05kJ/kgK
h2-h1=-lt,12
h1-h2h2=h1+(4,18+0,002t)*469,05+72*102 kJ/kg
=>T2= ==3539,19K
T=T2-T1=3539,19-469,05=3070,14K3.V=(0,4n)m3=4,4m3
pm=(1,5+n)bar=12,5bar=12,5*105Pa
t=(20+2n)C=42C=315,15K
t2=(700+10n) C=810C=1083,15K
pat=760mmHg=760/750*105=1,013*105Pa
p=pat+pm=1,013*105+12,5*105=13,513*105Paa).pentru H2:MH2=2 kg/kmol
pV=mRT=m*()*T =>m=kg n=
n= =>VN=n*VM=0,265kmol*22,413m3/kmol=5,93m3
tm=
CMp =CMp(600)+[CMp(700)-CMp(600)](tm-600)/(700-600)= = 29,33+(29,44-29,33)*(699,15-600)/100=29,43kJ/kmolKCMv=CMp-RM=29,43kJ/kmolK-8314,3*10-3kJ/kmolK=21,11kJ/kmolK
cv = =21,11/2=10,555kJ/kgKQ12=m*cv*(t2-t1)=4,53*10,555*(1083,15-315,15)=36721,26kJb).pentru CO2:
MCO2=44kg/kmol
CMp =47,32+(49,56-47,32)*(699,15-600)/100=49,54kJ/kmolKCMv =49,54kJ/kmolK 8,314kJ/kmolK=41,226kJ/kmolK
=
Q12=m*cv *(t2-t1)=4,53*0,936*768=3256,381kJ4.gaz perfect=0,001n kmoli=0,001*11=0,011kmoli
M=40kg/kmol
CMp=48kJ/kmolK
p1=1bar=105Pa
t1=27C=300,15K
a).transformare izocora:
T2=(2+0,05n)T1=765,382K
V-ct =>v1=v2p1V1=mRT1 => V1=mRMT1/Mp1=nMRMT1/Mp1=nRMT1/p1V1=0,011*8314,3*300,15/105=0,274m3V1=V2=0,274m3p1/T1=p2/T2 =>p2=p1T2/T1=105*765,382/300,15=2,549*105PaQ12=mcvT
n=m/M => m=n*M=0,011*40=0,44 kgcp-cv=R=RM/M => cv=cp-RM/M=1,2-8,314/40=0,992kJ/kgKcp=CMp/M=48/40=1,2kJ/kgK
Q12=0,44*0,992*(765,382-300,15)=203,064kJ
L12=0
U=Q12-L12=203,064kJ
H=Q12+V(p2-p1)=m*cp*(T2-T1)=0,44kg*1,2kJ/kgK*465,232K=245,642kJ
S=S2-S1=cv*ln(T2/T1)+R*ln(V2/V1)=0,992*0,936+8314,3*0=0,928kJ/Kb).transformare izobara: T2=(2+0,05n)T1=765,3825K
p=ct => p1=p2=105Pa
V1/T1=V2/T2 => V2= V1T2/T1=0,274*765,3825/300,15=0,6987m3Q12=mcp(T2-T1)=0,44*1,2*465,2325=245,642 kJL12=p1(V2-V1)=105*0,4247=0,4247*105JU=Q12-L12=245,642*103-0,4247*105=203172J=203,172 kJH=Q12=245,642 kJ
S=mcpln(T2/T1)-Rln(p2/p1)=0,44*1,2*0,936=0,494kJ/Kc) transformare izoterma: p2=(2+0,05n)p1=(2+0,05*11)*105=2,55*105Pa
T=ct => T1=T2=300,15K
p1/p2=V2/V1 =>V2=p1V1/p2=105*0,274/2,55*105=0,107m3
Q12=L12=p1V1ln(V2/V1)=105*0,274*(-0,94)=-25764,2kJQ12=L12=-25764,2kJ
U=Q12-L12=0
H=0
S=Q12/T=-25764/300,15=-85,837 kJ/K
d) transformare adiabatica: T2=(2+0,05n)T1=765,3825K
Q=0
p1V1k=p2V2kT1V1k-1=T2V2k-1 =>V2k-1=T1V1k-1/T2; V20,2=300,15*(0,274)0,2/765,3825=0,302m3k=cp/cv0=1,2/0,992=1,2
V2=0,0025m3p2=p1(V1/V2)k =>p2=105*(109,6)1,2=280,396*105PaQ12=0
U=mcvT=0,44*0,992*(765,3825-300,15)=203,064kJ
L12=-U=-203,064 kJ
H=mcpT=0,44*1,2*465,2325=245,642kJ
S=0e) transformare politropa: T2=(2+0,05n)T1=765,382K
p2=(2+0,05n)p1=(2+0,05*11)*105=2,55*105PaU=mcvT=0,44*0,992*(765,3825-300,15)=203,064kJ
H=mcpT=0,44*1,2*465,2325=245,642kJ
=>n=10
L12=(P1V1/n-1)(1-T2/T1)=(105*0,274/9)(1-765,382/300,15)=-4718,88kJQ12=(k-n)/(n-1)*L12=-4614,01kJ
S=cpln(T2/T1)-rln(p2/p1)=-193,45kJ/K
Transf.PresiuneVolumTemperaturaQ12L12U
HS
P1 (Pa)P2 (Pa)V1(m3)V2(m3)T1(K)T2(K)kJkJkJkJkJ
IzocoraV=ct
1052,549*1050,2740,274300,15765,382203,0640203,064245,6420,928
IzobaraP=ct1051050,2740,6987300,15765,382245,6420,4247* 105203,172245,6420,494
IzotermaT=ct1052,55* 1050,2740,107300,15300,15-25764,2-25764,200-85,837
AdiabataQ=0105280,396*1050,2740,0025300,15765,3820-203,064203,064245,6420
Politropa1052,55*1050,2740,249300,15765,382-4614,01-4718,88203,064245,642-193,45
5.
t=(200+n)C=211C=484,15Kp=(760-0,1*11)mmHg=758,9mmHg=758,9/750*105=1,011*105Pa
rCO2=(10+0,5*11)%=15,5%
rH2O=(50-0,2*11)%=47,8%
rN2=36,7%a) Mam=riMi=rCO2MCO2+rH2OMH2O+rN2MN2=
MCO2=44kg/kmol
MH2O=18kg/kmol
MN2=28kg/kmolcv=cp-R
Mam=RM/Ram => Ram=RM/Mam=8314,3/25,7=323,51J/kmol
cpam=gicpicp CO2=42/44=0,95 kJ/kgKcp H2O=36/18=2kJ/kgK
cp N2=30/28=1,07kJ/kgK
EMBED Equation.3
cpam=0,021*0,95+0,026*2+0,031*1,07=0,01995+0,052+0,03317=0,10512 kJ/kgKkam=0,10512*103/(0,10512*103-323,51)=105,12/(-218,39)=-0,48b) la stare normala: N=Mam/VM,N=323,51/22,414=14,433kg/m3 la starea la cos:
pV=mRT => p=mRT/V =>p=RT =>=p/RamT=1,011*105/323,51*484,15=0,645kg/m3_1289487675.unknown
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