Numerical identification of critical erosion prone areas in tube heat exchangers

The failure of tube heat exchangers is an acute problem in industry and, in most cases, is due to the solid particle erosion of a few tubes. Identifying the critical erosion surfaces and thereafter changing the particle impingement pattern on the surfaces is one of the solutions to increase the lifetime of heat exchangers. In this work the fluid flow, solid particle motion and metal erosion of different two-pass copper-tube heat exchangers were simulated with a refined model and the sophisticated RANS-SST approach. The results showed the importance of the model in capturing the asymmetrical flow, uneven fluid distribution through tube bundle and other flow features for better erosion prediction. The erosion characteristics of three heat exchangers were compared to evaluate their structure with respect to producing low erosion. The simulations provided basic data for identifying the critical areas and damage locations of each heat exchanger. It was found that the particle separation in the inlet header altered the critical erosion locations but did not significantly affect the erosion rate. Theerosion rates at critical areas were also predicted. The results can be applied for predicting the service life and improving the structure of tube heat exchangers.