Optimization of a shell and tube heat exchanger with staggered baffles using Taguchi method

Abstract

In this work, Taguchi method is applied on the numerical simulation results of a shell and tube heat exchanger with staggered baffles (STHX-ST) for the purpose of optimizing its design parameters corresponding to maximum heat transfer rate and minimum pressure drop. An STHX-ST integrates the characteristics of a shell and tube heat exchanger with segmental baffles as well as helical baffles. The baffles in these heat exchangers are oriented in such a way that a constant clockwise or counter clockwise angle is maintained between the adjacent baffles. The analysis of the shell side of these heat exchangers in this work is carried out using computational fluid dynamics (CFD) by varying its design parameters. The rate of heat transfer obtained and total pressure drop across the shell side of the heat exchanger is calculated using CFD. A set of experiments are designed as an orthogonal array as per Taguchi method through combinations of design parameters such as shell inside diameter, tube outside diameter, baffle cut, baffle spacing and baffle orientation angle. CFD Simulations are carried out on each parameter combination in this array. Finally signal to noise ratio analysis is conducted on this array and two set of optimum design parameters corresponding to maximum heat transfer and minimum pressure drop is obtained. The optimum combination of variables for maximum heat transfer yields a maximum heat transfer rate of 141252 W and the optimum parameter combination for minimum pressure drop yields a minimum pressure drop of 58352.6 Pa.