Comer subchannel

Wall subchannel Central subchannel Comer subchannel... 

Under the important assumption (to be discussed in Section II.B.3) that the flow through central subchannels is influenced negligibly by the walls, and that the flow through wall and comer subchannels is influenced only by the nearest wall, there is a high degree of symmetry within the channels. In Fig. 3 all symmetry lines are shown that result from these assumptions. A symmetry line is defined here as a line connecting points at which the derivative of the longitudinal velocity, with respect to the normal vector of the line, equals zero (i.e., duJdn = 0). 

Figure 4 The unit cells that make up the subchannels in rod bundles, (a) Central subchannels (b) wall subchannel (c) comer subchannel. The dashed boundaries of the unit cells indicate symmetry.

By solving Eq. (3) for rod bundles with different numbers of rods, it was shown [9] that an accurate estimation of the flow rate through wall, comer, and central subchannels is... 

In the subchannel analysis, 1/8 symmetry of the assembly is used. The geometry and designations of the various areas are shown in Fig. 2.79 [24]. The 1/8 assembly is divided into 70 subchannels (lower right drawing numbered 1-70 white areas) and includes 46 fuel rods (numbered 1-46 black circles), six water rods inside the assembly (numbered areas 1-6 in white squares or partial squares) and one water rod outside the assembly (numbered area 7). Three kinds of subchannels. A, B, and C, are used (upper left drawing). Subchannels A surround each comer of the six water rods inside the assembly. Subchannels C surround each comer of the assembly and they are surrounded by the water rod outside the assembly. Subchannels B... 

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