vsr · 2007. 2. 13. · i = 3 h m2 i (42) m˙ 1 = .5 [kg/s]; m˙ 2 = .5 [kg/s] (43) t 1,i = 30 [c];...
TRANSCRIPT
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VSR
Equations
$Local On
$INCLUDE TQ_Fct.txt
Program Verificarea unui Subracitor
procedure CMM (wc1, wc2 : wcmin, wcmax) (1)
If (wc1< wc2) then (2)
wcmin = wc1; wcmax = wc2; (3)
else (4)
wcmin = wc2; wcmax = wc1; (5)
endif (6)
end (7)
function GETEPS(SC$) (8)
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$Common NTC_max,wc_min,wc_max
If (SC$ = ‘CC’ ) then (9)
GETEPS=1− exp (−NTCmax · (1− wcmin/wcmax))
1− wcmin/wcmax · exp (−NTCmax · (1− wcmin/wcmax)); (10)
else (11)
GETEPS=1− exp (−NTCmax · (1 + wcmin/wcmax))
1 + wcmin/wcmax; (12)
endif (13)
end (14)
Procedura pentru determinarea temperaturilor curente ale fluidelor intr-un punct Sx al suprafetei
procedure GetTx (SC$, Nrpct : Sx,0..Nr,pct, t1,x,0..Nr,pct, ∆tx,0..Nr,pct, t2,x,0..Nr,pct) (15)
$Common t_1_i,t_2_i,t_1_e,t_2_e,S_e,NTC_max,wc_min,wc_max,Eps,wc_1,wc_2,k_Se
If (SC$ = ‘EC’ ) then (16)
Echicurent
µe = 1/wcmin + 1/wcmax (17)
∆ti = t1,i − t2,i (18)
duplicate i = 0, Nrpct (19)
Sx,i = i · Se/Nrpct (20)
ρx,i =1− exp
(−µe · kSe ·
∣∣∣0.001 kWW
∣∣∣ · Sx,i)1 + wc1/wc2
(21)
∆tx,i = (t1,i − t2,i) · exp(−µe · kSe ·
∣∣∣∣∣0.001 kWW∣∣∣∣∣ · Sx,i
)(22)
t1,x,i = t1,i − (t1,i − t2,i) · ρx,i (23)
t2,x,i = t1,x,i −∆tx,i (24)
end (25)
else (26)
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Contracurent
µc = 1/wc1 − 1/wc2 (27)
∆ti = t1,i − t2,e (28)
Fic =1− exp
(−µc · kSe ·
∣∣∣0.001 kWW
∣∣∣ · Se)1− wc1/wc2 · exp
(−µc · kSe ·
∣∣∣0.001 kWW
∣∣∣ · Se) (29)duplicate i = 0, Nrpct (30)
Sx,i = i · Se/Nrpct (31)
∆tx,i = (t1,i − t2,e) · exp(−µc · kSe ·
∣∣∣∣∣0.001 kWW∣∣∣∣∣ · Sx,i
)(32)
t1,x,i = t1,i − (t1,i − t2,i) ·1− Fic · wc1/wc2
1− wc1/wc2·(
1− exp(−µc · kSe ·
∣∣∣∣∣0.001 kWW∣∣∣∣∣ · Sx,i
))(33)
t2,x,i = t1,x,i −∆tx,i (34)
end (35)
endif (36)
end (37)
Marimi de intrare - vezi si fereastra Diagram
Ag$2 = ‘Water’ (38)
T$ = ‘Carbonsteel’ (39)
$IFNOT DiagramWindow
Ag1$ = ‘Ammonia’ (40)
SC$ = ‘CC’ (41)
Si = 3[m2]
(42)
ṁ1 = .5 [kg/s] ; ṁ2 = .5 [kg/s] (43)
t1,i = 30 [C] ; t2,i = 20 [C] (44)
De,i = 32 [mm] ·∣∣∣∣0.001 mmm
∣∣∣∣; deltat,i = 3 [mm] · ∣∣∣∣0.001 mmm∣∣∣∣ (45)
De,e = 57 [mm] ·∣∣∣∣0.001 mmm
∣∣∣∣; deltat,e = 3 [mm] · ∣∣∣∣0.001 mmm∣∣∣∣ (46)
Ru = 0.06× 10−3/0.12 m2-K/W (47)
Rp = 0.75× 10−3/1.5 m2-K/W (48)
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$EndIF
Di,i = De,i − 2 · δt,i; Di,e = De,e − 2 · δt,e (49)
Calculul Termic
λT = k (T$, 30 [C]) (50)
call Props
(Ag$1, t1,i, Po# ·
∣∣∣∣∣0.01 barkPa∣∣∣∣∣, 0 : ρ1, cp,1, λ1, η1, Pr1
)(51)
call Props
(Ag$2, t2,i, Po# ·
∣∣∣∣∣0.01 barkPa∣∣∣∣∣, 0 : ρ2, cp,2, λ2, η2, Pr2
)(52)
A1 = π ·D2i,e −D2e,i
4; A2 = π ·D2i,i/4; (53)
w1 =ṁ1
ρ1 · A1; w2 = ṁ2/ (ρ2 · A2) ; (54)
Re1 = ρ1 · w1 ·Di,e −De,i
η1; Re2 = ρ2 · w2 ·Di,i/η2; (55)
α1 = αCF,i (λ1, Pr1, Re1) ; Alpha2 = αCF,t (Di,i, λ2, Pr2, Re2) (56)
kSe =1
1/α1 + Ru + (De,i −Di,i) / (2 · λT ) · (2 ·De,i) / (De,i + Di,i) + (1/α2 + Rp) ·De,i/Di,i; (57)
wc1 = ṁ1 · cp,1; wc2 = ṁ2 · cp,2; (58)
call Cmm (wc1, wc2 : wcmin, wcmax) (59)
NTCmax = kSe ·∣∣∣∣∣0.001 kWW
∣∣∣∣∣ · Se/wcmin; (60)Eps= GETEPS(SC$) (61)
Calculul sarciii termice si a temperaturilor de iesire ale fluidelor
Q̇ = Eps· wcmin · (t1,i − t2,i) ; (62)
t1,e = t1,i − Q̇/wc1; t2,e = t2,i + Q̇/wc2; (63)
Trasarea variatiei temperaturilor fluidelor in lungul suprafetei
Nrpct = 10 (64)
call GetTx (SC$, Nrpct : Sx,0..Nr,pct, t1,x,0..Nr,pct, ∆tx,0..Nr,pct, t2,x,0..Nr,pct) (65)
$TABSTOPS 1 2 3 6 cm
Solution
Variables in Main program
4
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α1 = 6339 [W/m2-C] α2 = 4281 [W/m2-C] A1 = 8.294× 10−4 [m2]
A2 = 8.042× 10−4 [m2] δt,e = 0.0035 [m] δt,i = 0.003 [m]De,e = 0.057 [m] De,i = 0.038 [m] Di,e = 0.05 [m]Di,i = 0.032 [m] Eps= 0.3064 kSe = 631.8 [W/m2-C]λT = 60.38 [W/m-K] ṁ1 = 0.7 [kg/s] ṁ2 = 1 [kg/s]
Nrpct = 10 NTCmax = 0.4469 Q̇ = 12.47 [kW]
Re1 = 76089 Re2 = 39704 Rp = 5.000× 10−4 [m2-K/W]Ru = 5.000× 10−4 [m2-K/W] SC$ = ‘EC’ Se = 2.4 [m2]T$ = ‘Carbonsteel’ t1,e = 28.32 [C] t1,i = 32 [C]
t2,e = 22.98 [C] t2,i = 20 [C] wc1 = 3.393 [kW/K]
wc2 = 4.183 [kW/K] wcmax = 4.183 [kW/K] wcmin = 3.393 [kW/K]w1 = 1.425 [m/s] w2 = 1.246 [m/s]
Variables in Function AlphaCFi
αCF,i = 6339[W/m2·C
]λ = 0.4649 [W/m-C] Pr = 1.388
Re= 76089 DI,E = 0.05 [m] DE,I = 0.038 [m]Regim$ = ‘Regim turbulent’ Nu# = 163.6 DI,E = 0.05 [m]DE,I = 0.038 [m]
Variables in Function AlphaCFt
αCF,t = 4281[W/m2·C
]dech = 0.032 [m] λ = 0.586 [W/m-C]
Pr = 7.154 Re= 39704 Regim$ = ‘Regim turbulent’Nu# = 233.7 epstr = 1
Arrays
Row Ag$i ρi cp,i λi ηi Pri Sx,i t1,x,i ∆tx,i t2,x,i[kg/m3] [kJ/kg-C] [W/m-C] [Pa-s] [m2] [C] [C] [C]
0 0 32 12 201 Ammonia 592.1 4.847 0.465 1.33E-4 1.388 0.24 31.48 11.07 20.422 Water 998.2 4.183 0.586 1.00E-3 7.154 0.48 31.01 10.21 20.83 0.72 30.57 9.413 21.164 0.96 30.17 8.681 21.495 1.2 29.79 8.006 21.796 1.44 29.45 7.384 22.077 1.68 29.13 6.81 22.328 1.92 28.84 6.28 22.569 2.16 28.57 5.792 22.7810 2.4 28.32 5.342 22.98
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t-S
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