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Revise what inputs are needed into the functions and address issue #16 #39

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3c3f975
Added the framework for the Reynolds calculation, will probably split…
lcarasik Jan 24, 2019
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lcarasik Feb 8, 2019
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147 changes: 84 additions & 63 deletions TORCHE.py
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Original file line number Diff line number Diff line change
Expand Up @@ -7,7 +7,7 @@
^Ultra Safe Nuclear Corporation
^Advanced Systems Division

TOolbox for Reactor Cross-Flow Heat Exchangers:
TOolbox for Reactor Cross-Flow Heat Exchangers:
Python Scripts for calculation of Pressure drop and Heat Transfer in crossflow tube bundles based on models found across the literature.

Functionality:
Expand All @@ -22,6 +22,25 @@
import numpy as np
import sys

def Re_Calc():

# Staggered Tube Bank
if geom in ['staggered','STAGGERED','Staggered','triangular','TRIANGULAR','Triangular']:
if a <= (2*b**2 -.5):
v_max = u*(a/(a-1))
elif a > (2*b**2 -.5):
v_max = u*(a/(np.sqrt(4*b^2+a^2)-2))

# In-Line
if geom in ['inline','INLINE','Inline','square','SQUARE','Square']:
c = np.sqrt(b**2+(a/2)**2)
if c > (a+d)/2:
v_max= u*a/(a-d)
else:
v_max= u*a/(2(b-d))

return Re

def dP_Zu(rho,a,b,geom,N,u,Re,eta_wall=1, eta=1,alpha=0,beta=90):
'''
Description:
Expand All @@ -37,35 +56,35 @@ def dP_Zu(rho,a,b,geom,N,u,Re,eta_wall=1, eta=1,alpha=0,beta=90):
Output:
dP_total = Pressure Drop across tubes [Pa]
Warnings:
Validity:

Validity:
Reynolds number:
10 ≤ Re ≤ 10e6
Prandtl number:
0.7 < Pr < 500
Number of rows of tubes:
Nr >= 1
For in-line tube arrangement: a x b = 1.25 x 1.25; 1.5 x 1.5; 2.0 x 2.0.
For in-line tube arrangement: a x b = 1.25 x 1.25; 1.5 x 1.5; 2.0 x 2.0.
For staggered tube arrangement: a x b = 1.25 x ----; 1.5 x ----; 2.0 x ----.

Citation: Zhukauskas, A., R. Ulinskas. Heat Transfer in Tube Banks in Crossflow.
Hemisphere Publishing Corporation. New York, NY. 1988.
'''

if Re < 10:
print('The provided Reynolds number is out of the lower bounds (10) of validity at',Re)
elif Re > 10E6:
print('The provided Reynolds number is out of the higher bounds (10e6) of validity at',Re)

Pr = 10 # Hardcoded for now.
if Pr < 0.7:
print('The provided Prandtl number is out of the lower bounds (0.7) of validity at')
elif Pr > 500:
print('The provided Prandtl number is out of the higher bounds (500) of validity at')

if a != b:
print('Has not been added in yet: k_1 for unequal pitch-diameter ratios Can be found in graphical form in Zukauskas High Performance Single Phase Heat Exchangers Electronically found in cubic splines based of Re at: http://trace.tennessee.edu/cgi/viewcontent.cgi?article=1949&context=utk_gradthes')

x = (a-1)/(b-1)
v_max = u*(a/(a-1))
if geom in ['inline','INLINE','Inline','square','SQUARE','Square']:
Expand All @@ -90,44 +109,44 @@ def dP_Zu(rho,a,b,geom,N,u,Re,eta_wall=1, eta=1,alpha=0,beta=90):
c_2 = np.array([.102E3, -.202, .15]) #b = 1.25, 1.5, and 2
c_3 = np.array([-.286E3, 0, -.137]) #b = 1.25, 1.5, and 2
c_4 = np.array([0, 0, .396]) #b = 1.25, 1.5, and 2

##########Correction Factors #################

# Non-rectangular bundle # (valid up to Reynolds numbers of 150000)

k_1 = 1;
if x != 1.00:
if x != 1.00:
if (Re >= 1000 and Re < 10000):
k_1 = .9849*x**(-.8129)
elif (Re >= 10000 and Re < 70000):
elif (Re >= 10000 and Re < 70000):
k_1 = .9802*x**(-.7492)
elif (Re >= 70000 and Re < 150000):
elif (Re >= 70000 and Re < 150000):
k_1 = .988*x**(-.6388)
# Entry Losses #
# Entry loss coefficients (Re > 1E4 but < 1E6)
# Entry Losses #
# Entry loss coefficients (Re > 1E4 but < 1E6)
el_1 = np.array([1.9, 1.1, 1, 1, 1, 1, 1])
#Entry loss coefficients (Re > 1E6)
el_2 = np.array([2.7, 1.8, 1.5, 1.4, 1.3, 1.2, 1.2])
if (b == 1.25):
i = 0
elif (b == 1.5):
i = 1
elif (b == 2):
elif (b == 2):
i = 2
k_3 = 1

if (N < 7 and N > 0 and Re < 1E6 and Re > 1E2):
k_3 = el_1[N-1]
elif (N < 9 and N > 0 and Re > 1E6):
k_3 = el_2[N-1]
elif (Re <= 1E2):
print('Reynolds number needs to be greater than 100')

if geom in ['staggered','STAGGERED','Staggered','triangular','TRIANGULAR','Triangular']:
if a <= (2*b**2 -.5):
v_max = u*(a/(a-1))
if a > (2*b**2 -.5):
v_max = u*(a/(np.sqrt(4*b^2+a^2)-2))
v_max = u*(a/(np.sqrt(4*b^2+a^2)-2))
if Re < 1E3:
c_0 = [.795,.683,.343] #b = 1.25, 1.5, and 2
c_1 = [.247E3,.111E3,.303E3] #b = 1.25, 1.5, and 2
Expand All @@ -146,17 +165,17 @@ def dP_Zu(rho,a,b,geom,N,u,Re,eta_wall=1, eta=1,alpha=0,beta=90):
c_2 = [-.984E7, -.758E7, .792E8] #b = 1.25, 1.5, and 2
c_3 = [.132E11, .104E11, -.165E13] #b = 1.25, 1.5, and 2
c_4 = [-.599E13, -.482E13, .872E16] #b = 1.25, 1.5, and 2
if (b == 1.25):

if (b == 1.25):
i = 0
elif (b == 1.5):
i = 1
elif (b == 2):
i = 2

#Entry loss coefficients (Re > 1E2 but < 1E4)
el_1 = [1.4, 1.3, 1.2, 1.1, 1, 1, 1]
#Entry loss coefficients (Re > 1E4 but < 1E6)
#Entry loss coefficients (Re > 1E4 but < 1E6)
el_2 = [1.1, 1.05, 1, 1, 1, 1, 1]
#Entry loss coefficients (Re > 1E6)
el_3 = [.25, .45, .6, .65, .7, .75, .8]
Expand All @@ -180,14 +199,14 @@ def dP_Zu(rho,a,b,geom,N,u,Re,eta_wall=1, eta=1,alpha=0,beta=90):
elif eta_wall < eta and Re < 10E3:
p=0.968*np.exp(-1.076*Re**0.196)
k_2=(eta_wall/eta)**p

'''
Deviation form normal incidence
This needs to be better explained. It almost suggests that alpha CAN not be 0 and that beta CAN not be 90.
This needs to be better explained. It almost suggests that alpha CAN not be 0 and that beta CAN not be 90.
Rotated Crossflow (k4) and Inclined Crossflow(k5) angle of attack, α, may not be 0°, i.e., the bank maybe rotated at some arbitrary angle to the flow.
The angle of incidence β is not 90°, i.e. the flow is not exactly perpendicular to the tube bank.
The angle of incidence β is not 90°, i.e. the flow is not exactly perpendicular to the tube bank.
'''

k_4 = np.cos(np.deg2rad(alpha))
k_5 = 1
if beta != 90:
Expand All @@ -197,11 +216,11 @@ def dP_Zu(rho,a,b,geom,N,u,Re,eta_wall=1, eta=1,alpha=0,beta=90):
#Power series for Euler number per row. From same website as above.
Eu_p = (c_0[i])+(c_1[i]/Re**1)+(c_2[i]/Re**2)+(c_3[i]/Re**3)+(c_4[i]/Re**4)
Eu = Eu_p*k_1*k_2*k_3*k_4*k_5

#Using the relation Eu = dP/((1/2)*rho*v^2)
dP = Eu*((rho*v_max**2)/2) # Pressure drop per row [Pa]
dP_total = dP*N # Pressure drop across tube bundle [Pa]

return dP_total

def HT_Zu(rho,Pr,Pr_w,a,b,d,geom,N,u,Re):
Expand All @@ -222,30 +241,32 @@ def HT_Zu(rho,Pr,Pr_w,a,b,d,geom,N,u,Re):
Outputs:
Nu = Nusselt number
Warnings:
NOTE: Currently only applicable for staggered geometry
Validity:
NOTE: Currently only applicable for staggered geometry
Validity:
Number of rows of tubes:
Nr >= 2
Reynolds number:
100 ≤ Re ≤ 3x10e5
For in-line tube arrangement: 1.25 ≤ a ≤ 3.0; 1.2 ≤ b ≤ 3.0.
For in-line tube arrangement: 1.25 ≤ a ≤ 3.0; 1.2 ≤ b ≤ 3.0.
For staggered tube arrangement: 1.008 ≤ a ≤ 2.0; 1.008 ≤ b ≤ 2.0
10 < Re < 2e6 ???
0.7 < Pr < 500 ???
Citation: Zhukauskas, A., R. Ulinskas., 1988, "Heat Transfer in Tube Banks in Crossflow,"
Citation:
Zhukauskas, A., R. Ulinskas., 1988, "Heat Transfer in Tube Banks in Crossflow,"
Hemisphere Publishing Corporation. New York, NY. 1988.
Zukauskas, A., 1972, "Heat Transfer from Tubes in Cross Flow," Adv. in Heat Trans, vol. 8, Academic Press, New York.
'''

if Re < 100:
print('')

c = np.sqrt(b**2+(a/2)**2)
if c > (a+d)/2:
Vmax= a/(a-d)*u
else:
Vmax= a/(2(b-d))*u
if geom in ['inline','INLINE','Inline','square','SQUARE','Square']:

if geom in ['inline','INLINE','Inline','square','SQUARE','Square']:
n = 0.36
###Correction for less than 20 tube rows
if N <=14:
Expand All @@ -266,11 +287,11 @@ def HT_Zu(rho,Pr,Pr_w,a,b,d,geom,N,u,Re):
m = .83
else:
print( 'Re out of Range')

if geom in ['staggered','STAGGERED','Staggered','triangular','TRIANGULAR','Triangular']:
###Correction for less than 20 tube rows
if Re <= 1000 and N < 20:
c2= 1-np.exp(-np.sqrt(3*N**(1/np.sqrt(2))))
c2= 1-np.exp(-np.sqrt(3*N**(1/np.sqrt(2))))
if Re > 1000 and N < 20:
c2 = 1-np.exp(-N**(1/np.sqrt(3)))
### Coefficients based on range of Reynolds Number
Expand All @@ -295,11 +316,11 @@ def HT_Zu(rho,Pr,Pr_w,a,b,d,geom,N,u,Re):
n = 0.36
else:
print( 'Re out of Range')

Nu = c1*c2*(Re**m)*(Pr**n)*(Pr/Pr_w)**.25

return Nu

def dP_GG(rho,a,b,geom,N,u,Re,Return=""):
'''
Description:
Expand All @@ -316,18 +337,18 @@ def dP_GG(rho,a,b,geom,N,u,Re,Return=""):
Outputs:
dP_total = Pressure drop across tube bundle [Pa]
Warnings:
Not limited to specific pitch-diameter ratios within limits after a high enough Reynolds numbers.
Not limited to specific pitch-diameter ratios within limits after a high enough Reynolds numbers.
The Reynolds number is based on the maximum velocity in the narrowest area between tubes.
Validity:
Reynolds number:
1 =< Re =< 3x10e5
Number of rows of tubes:
Nr >= 5
In the range Re < 10E3:
For in-line tube arrangement: a x b = 1.25 x 1.25; 1.5 x 1.5; 2.0 x 2.0.
In the range Re < 10E3:
For in-line tube arrangement: a x b = 1.25 x 1.25; 1.5 x 1.5; 2.0 x 2.0.
For staggered tube arrangement: a x b = 1.25 x 1.0825; 1.5 x 1.299; 1.768 x 0.884.
In the range Re ≥ 10E3:
For in-line tube arrangement: 1.25 ≤ a ≤ 3.0; 1.2 ≤ b ≤ 3.0.
In the range Re ≥ 10E3:
For in-line tube arrangement: 1.25 ≤ a ≤ 3.0; 1.2 ≤ b ≤ 3.0.
For staggered tube arrangement: 1.25 ≤ a ≤ 3.0; 0.6 ≤ b ≤ 3.0; c ≥ 1.25.
Citation: VDI. VDI Heat Atlas. Berlin, Heidelberg: VDI-Buch-Springer, 2010. Chapter L1
Gaddis, E., Gnielinski, V., 1985, "Pressure drop in cross flow across tube bundles," Int. Chem. Eng., vol. 25(1), pp. 1-15
Expand All @@ -341,7 +362,7 @@ def dP_GG(rho,a,b,geom,N,u,Re,Return=""):
f_nt = 0 # Coefficient for influence of inlet and outlet pressure losses
elif N <=5:
sys.exit('Model only valid for greater than 5 tubes')
f_ti = (0.22+1.2*(1-(0.94/b))**(0.6)/(a-0.85)**1.3)*10**(0.47*(b/a-1.5))+0.03*(a-1)*(b-1) # Coefficient for geometric arrangement factor
f_ti = (0.22+1.2*(1-(0.94/b))**(0.6)/(a-0.85)**1.3)*10**(0.47*(b/a-1.5))+0.03*(a-1)*(b-1) # Coefficient for geometric arrangement factor
D_turb = f_ti/(Re**(.1*b/a)) # Drag coefficient due to turbulent flow
D_tot = D_lam+(D_turb+f_nt)*(1-np.exp(-(Re+1000)/2000))
if geom in ['staggered','STAGGERED','Staggered','triangular','TRIANGULAR','Triangular']:
Expand All @@ -361,18 +382,18 @@ def dP_GG(rho,a,b,geom,N,u,Re,Return=""):
f_nt= (1/a**2)*(1/N-.1) # Coefficient for influence of inlet and outlet pressure losses
elif N > 10:
f_nt = 0 # Coefficient for influence of inlet and outlet pressure losses
f_ts = 2.5+1.2/(a-0.85)**1.08+0.4*(b/a-1)**3-0.01*(a/b-1)**3 # Coefficient for geometric arrangement factor

f_ts = 2.5+1.2/(a-0.85)**1.08+0.4*(b/a-1)**3-0.01*(a/b-1)**3 # Coefficient for geometric arrangement factor
D_turb = f_ts/Re**0.25 # Drag coefficient due to turbulent flow
D_tot = D_lam+(D_turb+f_nt)*(1-np.exp(-(Re+200)/1000)) # Total drag coefficient based on laminar and turbulent contributions

if Return == "D_tot":
return D_tot

dP_total = .5*D_tot*(N*rho*u0**2) # Pressure drop across tube bundle [Pa]

return dP_total

def HT_GG(rho,Pr,a,b,d,geom,N,u,Re):
'''
Description:
Expand All @@ -389,35 +410,35 @@ def HT_GG(rho,Pr,a,b,d,geom,N,u,Re):
Re = Reynolds number calculated based on velcoity at narrowest point and outside tube diameter
Outputs:
Nu = Nusselt Number
Validity: 10 < Re < 2e6
Validity:
10 < Re < 2e6
0.7 < Pr < 500
Warnings:
Ranges of validity have yet to be included in this script. Information soon to come.
Citation: Martin, H., 2002, “The Generalized Lévêque Equation and its practical use for the prediction of heat and mass transfer rates from pressure drop,”
Chem. Eng. Sci., vol. 57, pp. 3217-3223.
'''

if b > 1:
dh=((4*a/np.pi)-1)*d # Hydraulic diameter [m]
else:
dh=((4*a*b/np.pi)-1)*d # Hydraulic diameter [m]

if geom in ['inline','INLINE','Inline','square','SQUARE','Square']:
L=b*d

if geom in ['staggered','STAGGERED','Staggered','triangular','TRIANGULAR','Triangular']:
c=((a/2)**2+b**2)**.5
L=c*d

xi = dP_GG(rho,a,b,geom,N,u,Re,"D_tot") # Drag Coefficient from Gaddis-Gnielinski Pressure Drop Model
if Re > 2.5e5:

if Re > 2.5e5:
xi = xi*(1+(Re-2.5e5)/3.25e5) # Correction made Holger Martin for use in Heat Transfer calculation

xi_f = .5*xi # Total drag coefficient used to calculate drag coefficient due to friction ~.5

NuPr = 0.404*(xi_f*Re**2*dh/L)**(1/3) #Nu/Pr**(1/3)
Nu = NuPr*(Pr)**(1/3)

return Nu