550
H. Najmi et al.
Table 1 Outlet mass flowrate and recovery percentage
Mass flowrate (g/s)
Recovered (%)
Inlet Cell 1 Cell 2 Cell 3 Cell 4 Cell 5 Cell 6 Cell 7 Cell 8 S.O
0.30 0
0.002 0
0.002 0.010 0.011 0.008 0.009 0.068 37.09
0.69 0.028 0.037 0.031 0.029 0.025 0.035 0.034 0.024 0.191 63.50
0.90 0.039 0.049 0.042 0.042 0.035 0.050 0.048 0.040 0.263 68.05
1.11 0.049 0.060 0.054 0.056 0.046 0.065 0.058 0.055 0.335 70.45
1.28 0.062 0.069 0.064 0.066 0.057 0.077 0.067 0.067 0.394 72.42
1.50 0.075 0.081 0.077 0.080 0.065 0.091 0.079 0.081 0.445 71.80
be due to uncertainty of the mass flow meter because the mass flowrate measured
at cell outlet is very small. Even for higher mass flowrates (more than 1.00 g/s), the
recovered flow is about 60–70% which means 40–30% of mass is lost (see Table 1).
Few more tests are performed by changing the position of two mass flowmeter
whereas one is permanently placed at secondary outlet (i.e., MFM C see Fig. 1). It
is found that whenever the mass flowmeter position is changed, the mass flowrate
through the secondary outlet and cells also varies (See Fig. 2).
The above results suggest that the position of the flow meter affects the flow
through the porous tube. After analyzing the obtained results, it is confirmed that the
reason behind this is the Coriolis mass flow meter which offers a small resistance
to the incoming flow. Therefore, if one mass flow meter is connected at cell 1 and
other at cell 5, the fluid will take the easiest path and will escape from the outlets (2,
3, 4, 6, 7 or 8) open to the atmospheric pressure. Hence, this method is not reliable
and cannot be used for the measurement of the mass flowrate through primary and
secondary outlets. A new method is required in order to determine the mass flowrate
accurately through various outlets.
In this work, a new method has been developed to measure the mass flowrate
from each cell precisely without changing the position of the mass flow meter. It
works on mass balancing technique. The two mass flow meters at the primary outlet
are named as MFM A and MFM B. The last mass flow meter is named as MFM C
and placed at secondary outlet permanently. After that, all the primary outlets are
connected to both the mass flow meters, i.e., MFM A and MFM B. This is facilitated
by a three-way valve attached to each permeation cell as described above. It also
ensures that all the outlets offer the same resistance to the outflow.
During the experiments, it is made sure that at a time, only four outlets are
connected to each mass flow meter, i.e., MFM A and MFM B. It means if the primary
outlet 1, 5, 7, and 8 are connected to MFM A, the reaming outlets, i.e., 2, 3, 4, and 6
will be connected to MFM B whereas the MFM C will always remain at secondary
outlet.
To determine the accurate mass flowrate from each outlet for a given inlet mass
flowrate, MFM A and MFM B are required to measure the primary outlet mass
flowrate seven times using different combinations of the outlets (see Table 2).
H. Najmi et al.
Table 1 Outlet mass flowrate and recovery percentage
Mass flowrate (g/s)
Recovered (%)
Inlet Cell 1 Cell 2 Cell 3 Cell 4 Cell 5 Cell 6 Cell 7 Cell 8 S.O
0.30 0
0.002 0
0.002 0.010 0.011 0.008 0.009 0.068 37.09
0.69 0.028 0.037 0.031 0.029 0.025 0.035 0.034 0.024 0.191 63.50
0.90 0.039 0.049 0.042 0.042 0.035 0.050 0.048 0.040 0.263 68.05
1.11 0.049 0.060 0.054 0.056 0.046 0.065 0.058 0.055 0.335 70.45
1.28 0.062 0.069 0.064 0.066 0.057 0.077 0.067 0.067 0.394 72.42
1.50 0.075 0.081 0.077 0.080 0.065 0.091 0.079 0.081 0.445 71.80
be due to uncertainty of the mass flow meter because the mass flowrate measured
at cell outlet is very small. Even for higher mass flowrates (more than 1.00 g/s), the
recovered flow is about 60–70% which means 40–30% of mass is lost (see Table 1).
Few more tests are performed by changing the position of two mass flowmeter
whereas one is permanently placed at secondary outlet (i.e., MFM C see Fig. 1). It
is found that whenever the mass flowmeter position is changed, the mass flowrate
through the secondary outlet and cells also varies (See Fig. 2).
The above results suggest that the position of the flow meter affects the flow
through the porous tube. After analyzing the obtained results, it is confirmed that the
reason behind this is the Coriolis mass flow meter which offers a small resistance
to the incoming flow. Therefore, if one mass flow meter is connected at cell 1 and
other at cell 5, the fluid will take the easiest path and will escape from the outlets (2,
3, 4, 6, 7 or 8) open to the atmospheric pressure. Hence, this method is not reliable
and cannot be used for the measurement of the mass flowrate through primary and
secondary outlets. A new method is required in order to determine the mass flowrate
accurately through various outlets.
In this work, a new method has been developed to measure the mass flowrate
from each cell precisely without changing the position of the mass flow meter. It
works on mass balancing technique. The two mass flow meters at the primary outlet
are named as MFM A and MFM B. The last mass flow meter is named as MFM C
and placed at secondary outlet permanently. After that, all the primary outlets are
connected to both the mass flow meters, i.e., MFM A and MFM B. This is facilitated
by a three-way valve attached to each permeation cell as described above. It also
ensures that all the outlets offer the same resistance to the outflow.
During the experiments, it is made sure that at a time, only four outlets are
connected to each mass flow meter, i.e., MFM A and MFM B. It means if the primary
outlet 1, 5, 7, and 8 are connected to MFM A, the reaming outlets, i.e., 2, 3, 4, and 6
will be connected to MFM B whereas the MFM C will always remain at secondary
outlet.
To determine the accurate mass flowrate from each outlet for a given inlet mass
flowrate, MFM A and MFM B are required to measure the primary outlet mass
flowrate seven times using different combinations of the outlets (see Table 2).