simulation and cfd analyses of condensing shell and tube heat exchanger for chp package application

Simulation and computational fluid dynamic (cfd) analyses of condensing shell and tube heat exchanger is subjected in this article. the condensing model using a user defined function (udf) through ansys fluent 18.2 is developed. also, the heat transfer between the shell and tube bundles is considered too. the subjected heat exchanger included seven tubes with a length of 600 mm and a shell with a diameter of 90 mm. the effect of different types of baffles and the distance between them is investigated in this article. all the calculations were done in three different mass flow rates. finally, the distribution of heat flow is depicted for each stage of the considered heat exchanger. results show that for the specific geometry and constant distance between baffles, increment in the mass flow rate leads to increasing the heat transfer coefficient. in addition, it shows that the formation of dew droplets and condensed water is higher in the first geometry due to the maximum heat transfer by hot flue gas.