earticle

영어

The reliability of shell and tube heat exchanger is predicted using a 2-stage physics-based simulation. The first stage uses stochastic porous models of the bundle to estimate operational and environmental uncertainties in flow conditions, such as flow velocity and inlet temperature. The results are used for the second stage, which is the CFD simulation of the sub-model. The most critical part of shell and tube heat exchangers is the tube bundle. The technique integrates stochastic fluid-structure interaction with fatigue and Monte Carlo simulations. Heating loads are transferred between models by mapping of actual temperature distributions. A sensitivity analysis is conducted to determine the significant factors that may lead to failure, as it is impractical to consider all input variables. In the sub-model, which is a tube bank, air flow and heat transfer inter-effects between the three tubes and the fins are measured. Thermal stresses are highest at the bonding regions between the water tubes and the fins, and that is because of the high temperature gradient combined with different material properties. Thermal stress in the model is relatively low, however, it has a high effect on fatigue life, and consequently on reliability result. The presented model can be used as a useful tool for reliability-based design of shell and tube heat exchangers.