Modeling and simulation of onset of condensation-induced water hammer

In view of the importance of the condensation-induced water hammer in various engineering fields, this study performed an analytical modeling and numerical simulation to obtain the map of the onset of the condensation induced water hammer. Two linear boundaries were experimentally observed for the transitions between no condensation-induced water hammer and non-periodic condensation-induced water hammer and between non periodic condensation-induced water hammer and periodic condensation-induced water hammer. The analytical modeling based on the energy balance equation was conducted to derive the onset of the condensation-induced water hammer. The analytical model suggested that the map of the onset of the condensation-induced water hammer could be displayed by two essential non-dimensional parameters, such as modified Jakob number and Froude number. The model indicated that the slope of the boundary of the onset of the condensation-induced water hammer was the product of modified Stanton number, non-dimensional interfacial area concentration, and non-dimensional temperature difference. The model could predict the boundaries between no condensation induced water hammer and non-periodic condensation-induced water hammer and between non-periodic condensation-induced water hammer and periodic condensation-induced water hammer satisfactorily. The one-dimensional nuclear thermal-hydraulic system analysis code, RELAP5, was used for simulating the onset of the condensation-induced water hammer. The obtained boundary corresponded to the experimentally obtained boundary between non-periodic condensation-induced water hammer and periodic condensation-induced water hammer.