Flow recirculation data for closed-ended branch piping (deep cavity flow)

Many auxiliary lines of different sizes are tied into the primary heat transport system piping of nuclear reactors and other similar types of systems. Often these lines are valve closed so that the contained fluid is either stagnant or flowing at low velocity due to free convection or small amounts of valve leakage. The characterization of the axial temperature distributions in these lines is important because of potential structural consequences to the piping. For example, in addition to being required for determining basic thermal expansion allowances in piping networks, axial temperature distributions are needed relative to other considerations, such as thermal fatigue, which could occur because the leakage flow has a different temperature from that of the trunk line that it flows into at the juncture of the two pipes. As would be anticipated, conditions that result in larger fluid temperature differences at a particular network juncture generally result in the more severe structural impact (e.g., thermal stratification/striping assessments become necessary). Prediction of the flow recirculation back into the branch piping is critical for calculation of the junction temperatures and is the subject of this study