Dynamic modeling of heat exchanger tube rupture

One fault that occurs with heat exchangers is a tube rupture, an overpressure scenario in which high pressure fluid flows into the low pressure region. It is a serious safety concern that may lead to significant damage. Accurate prediction of the pressure build-up after a rupture is critical to determine the appropriate size of a relief device and avoid exceeding allowable pressure limits. This paper describes a model-based step-by-step methodology to predict dynamic pressure profiles during tube rupture for liquid-liquid, vapor-liquid, and flashing liquid-liquid systems. The transient effects of the relief valve are considered. The effects of choked flow must also be considered for accurate maximum pressure predictions. Using a dimensionless analysis, the pressure ratio and density ratio are shown to significantly impact the severity of this incident. Results show that vapor-liquid systems result in the highest pressure surges.