468
7 Applications: Pebble Flow Optimizations
Fig. 7.21 Impact of insert
height on flow pattern
part with an originally uniform flow. The heightened insert (1.5H out ) has influenced
the upper flow field in the bin, which is unnecessary and detrimental; this is why the
heightened insert brings about the side effect to the flow field in the bin part. The
insert is prohibited from interfering with the bin part by restricting its height and
adjusting its location.
For further comparing the performance of inserts with the height of 0.5H out and
H out , three characteristic values are calculated (refer to Fig. 7.22). In the application,
the insert with the half hopper height works even better than the normal height one
from all three aspects. Therefore, a flat insert, which is shorter than the hopper, is more
recommended when the right sizes of the inlet and the outlet have been determined.
This kind of insert can ensure the balancing effect in the hopper and minimize its
side effect on the flow field in the bin at the same time. It is more appropriate for the
slow and discharge-controlled flow in HTGR, at least.
7.3.5.3 Location of Insert
The insert should be located at the right place to correct the flow in a pebble bed.
Usually, the joining region between the bin and the hopper is the place where nonuniform flow initiates, and an insert is recommended to be placed across the bin–
7 Applications: Pebble Flow Optimizations
Fig. 7.21 Impact of insert
height on flow pattern
part with an originally uniform flow. The heightened insert (1.5H out ) has influenced
the upper flow field in the bin, which is unnecessary and detrimental; this is why the
heightened insert brings about the side effect to the flow field in the bin part. The
insert is prohibited from interfering with the bin part by restricting its height and
adjusting its location.
For further comparing the performance of inserts with the height of 0.5H out and
H out , three characteristic values are calculated (refer to Fig. 7.22). In the application,
the insert with the half hopper height works even better than the normal height one
from all three aspects. Therefore, a flat insert, which is shorter than the hopper, is more
recommended when the right sizes of the inlet and the outlet have been determined.
This kind of insert can ensure the balancing effect in the hopper and minimize its
side effect on the flow field in the bin at the same time. It is more appropriate for the
slow and discharge-controlled flow in HTGR, at least.
7.3.5.3 Location of Insert
The insert should be located at the right place to correct the flow in a pebble bed.
Usually, the joining region between the bin and the hopper is the place where nonuniform flow initiates, and an insert is recommended to be placed across the bin–