Study on Tube Pulling Apart Load in Tubular Heat Exchangers With FEA Method

Abstract

Tube pulling apart loads of tube-and-shell heat exchangers are very complicated, because these loads are affected by many factors, such as, tube to tubesheet joint structure, pressure, and temperatures. The tubes may break or be fouled during the service, which will result in change of tube metal temperatures and affect pulling loads. Some tubes may be pulled out from the tubesheet because of too much high tube pulling apart loads and the heat exchanger cannot be operated normally. Depending on the different flow passes of the fluid and the temperature change in the service, the tube pulling loads for several cases with different temperature distribution are calculated and analyzed for a heat exchanger using finite element (FE) method. The results show that the pulling loads of different tubes are different obviously. The pulling loads of the heat exchanger are assessed with ASME Code. The maximum pulling load is over the allowable force. FE method is a good technique to assess the distribution of the pulling loads and the location of the maximum pulling load. So it is useful and important to use FE method for forecasting the break and leak of the tubes.