The release rate from side 1A and 2B is calculated based on
isentropic expansion from almost a stagnant conditions in the
respective inlet and outlet chambers of the exchanger, at the
respective pressures and temperatures indicated earlier. The isentropic
expansion from the respective chamber conditions is performed
based on the mixture composition given in Table 1. The
resulting release rates for both the hot and cold sides for these two
locations are shown in Fig. 7, assuming a discharge coefficient of
0.84. The value of the discharge coefficient is based on compressible
flow and back pressure to stagnation pressure ratio of approx. 0.2
(as the expected shell pressure to be around 2000 kPa-a and
stagnation pressure of 9757 kPa-a). (Note that site ambient pressure
is ~97 kPa-a). This is based on a corresponding value of the
incompressible discharge coefficient (Cd) for the full-bore ruptured
tube of 0.6e0.65 (Benedict, 1971). Note that choked flows increase
the discharge coefficient (Cd). The release rates at all other locations
follow a frictional adiabatic (Fanno) flow along the respective
length of the tube (locations 1B, 2A, 3A and 3B). This is also performed
using RefProp 9.1. The results of all of these calculations are
summarized in Table 2. It is shown that the highest release rate
among the three identified locations in Fig. 6 is location 2 with a
combined total release rate from both sides ¼ 3.358 kg/s. Since this
release rate will result in the highest surge pressure in E-10 and
surrounding systems, the results will only be shown for the tube
rupture scenario at location 2. It should be noted that both E-10 and
E-11 exchangers are not equipped with PSVs or rupture discs.