Effect of diamond-shaped turbolator on optimization of shell and tube heat exchanger.

In present study, the thermal modeling and multi-objective optimization of shell and tube heat exchangers (STHE) with a diamond-shaped turbulator has been investigated. To obtain the Correlation relationship between the Nusselt number and the friction factor for a diamond-shaped turbulator, a CFD analysis with acceptable accuracy has been done. Two factors of total cost and maximum thermal effectiveness are chosen as two objective functions. Nine optimal design variables for the present study are arrangement, diameter, step ratio, length and number of tube, distance ratio and cut ratio of baffle, turbulator step ratio and turbulator internal rod diameter. The e-NTU procedure is employed for thermal modeling STHE and the Bell-Delaware technique is applied to evaluate the coefficient of heat transfer and pressure drop of the shell side. Also NSGA-II is used to acquire two objective functions. Comparison of the obtained results of the optimal Pareto optimal solutions showed that the use of diamond-shaped turbulator DST on the tube side improves thermal performance and lower overall costs STHE compared to the non-use state. Using turbulator inside the tube and the impact of important design parameters clearly contributed to the difference between effectiveness and overall cost. [ABSTRACT FROM AUTHOR]