Abstract
Round rod baffle (RRB), plain plate baffle (PPB), wavy-shaped plate baffle (WSB) and polygonal-shaped plate baffle (PSB) are four commonly used baffles in parallel flow shell and tube heat exchangers (STHXs). Comparative study of these four different baffles are numerically carried out using different performance indicators including Nusselt number, friction factor, performance evaluation criterion, entropy generation ratio, and entransy dissipation ratio for flow in full turbulent regime. Heat transfer mechanism has also been discussed. Correlations for Nusselt number and friction factor are fitted and the cost estimation using Hall’s method is compared. It is found that the Nusselt number of STHX-PPB, STHX-WSB, and STHX-PSB increased by 20.9%, 15.2%, and 23.9% averagely compared with STHX-RRB, respectively. The friction factor can be increased on average by 142.0%, 154.5%, and 242.4%, respectively. However, the overall performance of them is only 90.1%, 84.4%, and 82.3% that of STHX-RRB, respectively. The sequence of entropy generation and entransy dissipation is STHX-RRB > STHX-WSB > STHX-PPB > STHX-PSB. The inlet Re and baffle distance have significant effects on different performance indicators while the baffle width does not. Finally, the results show that the STHX-PSB can reduce the total cost as it has better ability on heat enhancement.
Comparative study of the thermal performance of four different parallel flow shell and tube heat exchangers with different performance indicators
