Page 131 - Process Modelling and Simulation With Finite Element Methods

11 P Process Modelling and Simulation with Finite Element Methods

Table 3.1 Specific gravity of liquid water.

So what does one of these expansivity functions look like? See Figure 3.4 below.4 below.

-.-,ILL . ~~
-'3% 320 340 360

-0.01

-0.02 '

-0.03

-0.04

P(T)-Po
Figure 3.4 Expansivity ___ vs. Temperature (K) for water.
Po

Next, how do we organize this data so as to use it in the FEMLAB GUI? You
should find the m-file watrdemm, which is a MATLAB function m-file that
interpolates using cubic splines within Table 3.1 to find the dimensionless
expansivity factor. This m-file is reproduced here:

function a=watrdens(ttemp)
%WATRDENS Interpolates the expansivity of water in 273 and 373
deg K
temp=[O 3.98 5 10 15 18 20 25 30 35 38 40 45 50 55 60 65 70 75 80
85 90 95 1001;
dens=[0.99987 1. 0.99993 0.99973 0.39913 0.99862 0.99823 0,99707
0.99567 0.99406 0.99299 0.99224 0.99025 ...
0.98807 0.98573 0.98324 0.98059 0.97781 0.97489 0.97183 0.96865
0.96534 0.96192 0.958381 ;
temp=temp+273;
dens= (dens-dens (1) )/dens (1) ;
a=interpl (temp,dens,ttemp, 'spline')
;