Specific Heat and Viscosity Nomographs for Calcium Chloride Brines IKCE calcium chloride solutions find wide application
D. S. DAVIS
S
as refrigerating brines, reliable specific heat ( 2 ) and viscosity (1) data are necessary in connection with the design of cooling systems. The purpose of this paper is to present such data in convenient nomographic form.
Michigan Alkali Company, Wyandotte, Mich,
Specific Heats
where ,u is the viscosity of the brine in centiposes, and a and b depend upon the percentage of anhydrous calcium chloride, c, as follows:
The line coordinate specific heat chart (Figure 1) is based on the correlation equation, cp
=
a
where cp = specific heat, t = temperature,
+ b [ t - 6.9 (10)-0'028t1 F. t. u./(lb.) F.
C
1.250 0.6604 3225
16 18 20 22 24
(" F.)
and u and b depend upon the specific gravity of the brine, F, as follows: 8 a b (107)
log p = a
1.225 0.6794 3675
1.200 0.7040 3743
1.175 0.7278 3821
The use of the chart is illustrated as follows: T h a t is the specific heat of a calcium chloride brine at -4' F. which has a specific gravity of 1.218? Connect 1.218 on the 6 scale with -4 on the t scale and read the specific heat as 0.681 B. t. u./(pound)(" F.) on the cp scale.
a 0.785 0.817 0.861 0.891 0.930
+ b [ l - 8.4 (10)0.164']
b -0,0114 -0,0113 -0.0118 -0.0113 -0.0111
C
a
26 28 30 32
0.983 1.048 1.118 1.196
b -0,0111 -0.0111 -0.0113 -0.0116
The use of the chart is illustrated as follows: What is the viscosity of a calcium chloride brine a t 5" F. when the concentration is 23 per cent? Connect 23 on the c scale with 6 on the t scale and read the viscosity as 7.1 centipoises on the p scale. For all design purposes values read from the charts are in sufficient agreement with the original data.
Literature Cited (1) Am. SOC.of Refrig. Engrs. Data Book (1939-40). (2) Calcium Chloride .4ssoc., Bull. 30, 19 (1942).
Viscosities The line coordinate viscosity chart (Figure 2 ) is based on the correlation equation which follow.
c, Per cent CaCIt
p, l45coaty, cent lpoises
30
40
30 /
/'
r L
/5
20
20
10
I
\
0'65
0.63
FIGURE 2
FIGURE 1
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