I decided I would suffer today for the good of the community and = made a spreadsheet comparing Pressure Drops with Different Coolants. I have = attached the spreadsheet so that you guys can play around with it. All values are = locked except the ones highlighted. Unprotect the other values if you want, but = do not blame me if you mess it up.

Note that Diameter, Flow rate and pipe roughness all have and = effete on pressure drop and it is NON Linear. This means % change from 50/50 is = different for different configurations.

I guessed at some approximate = values for D, Vd and e. Also the density values in my = text book for water conflicted with those given by Evans. I went with the Evans = values but I do not trust them.

This sheet models a strait tube = of constant diameter with turbulent fluid flow. =

With some time investment this = could be made to more accurately model an aircraft cooling system (multiple = diameters, fittings, bends, ect) but this gives a good = ball park figure of pressure drop differences. To take it another step we could do = some of the thermal calculations to. But this is all I am doing for = now.

I would greatly appreciate it if = someone with knowledge of fluids could check my work. =

Disclaimer: These are only model = estimates and have some associated error.

Alex Madsen =

Comparison of Pressure Drops with Different = Coolants

equation=

Water

50/50

NPG+
=

Temp (C)

212=

212=

212=

D Pipe Diameter = (ft)

0.167

u dynamic viscosity = (lbm/ft*s)

0.0001882<= /font>

0.0004704<= /font>

0.0015455<= /font>

Flow Rate = (GPM)

30.00

p density (lbm/ft^3)

61.8

64.9

65<= /p>

Vd Flow Rate (ft^3/s)

0.06684

v kinematic viscosity = (ft^s/s)

u/p

3.05E-06

7.25E-06

2.38E-05

V velocity (ft/s)

3.065

L Pipe Length (ft)

1.000

RE Reynolds Number

V*D/v

167,759.41=

70,484.79<= /font>

21,486.34<= /font>

f Approximate turbulent friction = factor

((-1.8*LOG10(6.9/Re+((e/D)/3.7)^1.1))^(-1))^2

0.0174

0.0200

0.0257

e Pipe Roughness = (ft)

0.0000330<= /font>

delta P change in pressure = (lb/ft^2)

f*L*p*V^2/(D*2)

30.28

36.59

47.04

delta P change in pressure = (PSI)

0.210<= /o:p>

0.254<= /o:p>

0.327<= /o:p>

% change from 50/50

-17.23

0.00

28.59

	Comparison of Pressure Drops with Different = Coolants

	equation=	Water	50/50	NPG+ =
Temp (C)		212=	212=	212=	D Pipe Diameter = (ft)	0.167
u dynamic viscosity = (lbm/ft*s)		0.0001882<= /font>	0.0004704<= /font>	0.0015455<= /font>	Flow Rate = (GPM)	30.00
p density (lbm/ft^3)		61.8	64.9	65<= /p>	Vd Flow Rate (ft^3/s)	0.06684
v kinematic viscosity = (ft^s/s)	u/p	3.05E-06	7.25E-06	2.38E-05	V velocity (ft/s)	3.065
					L Pipe Length (ft)	1.000
RE Reynolds Number	V*D/v	167,759.41=	70,484.79<= /font>	21,486.34<= /font>

f Approximate turbulent friction = factor	((-1.8*LOG10(6.9/Re+((e/D)/3.7)^1.1))^(-1))^2	0.0174	0.0200	0.0257	e Pipe Roughness = (ft)	0.0000330<= /font>

delta P change in pressure = (lb/ft^2)	fLpV^2/(D2)	30.28	36.59	47.04
delta P change in pressure = (PSI)		0.210<= /o:p>	0.254<= /o:p>	0.327<= /o:p>
% change from 50/50		-17.23	0.00	28.59