A Distribution Parameter Derived for Rectangular Channels and Simulated Subchannel Geometry

The distribution parameter of the drift-flux model has been developed for a rectangular channel and a simulated boiling water reactor (BWR) subchannel. The void fraction prediction by the subchannel drift-flux code CANAL is well demonstrated for heated rectangular channels. Intrasubchannel flow and void profiles are considered for subchannel model development. Distribution parameter C₀ is found to be very sensitive to variation of the geometric parameters and subchannel types. Since void fraction measurements corresponding to the rectangular subchannel of a BWR rod bundle are unavailable at present, assessment of the derived models remains to be performed.