Multivariate optimization and sensitivity analyses of relevant parameters on efficiency of scraped surface heat exchanger

Abstract

In the current paper, a Scraped Surface Heat Exchanger (SSHE), composed of an encased rotor on which two blades are mounted, is studied. The focus is on the effects of the rotor speed, mass flow rate, and outgoing heat flux applied on the shell on the Convection Heat Transfer Coefficient (CHTC) and the Outlet Temperature (OT). To this end, the Response Surface Methodology (RSM) is utilized to achieve the regression modeling and sensitivity analysis. Then, the Nondominated Sorting Genetic Algorithm II (NSGA-II) algorithm is applied to best balance the two conflicting objectives of maximizing CHTC and minimizing OT. The results show that an increase in either the rotation speed of the rotor or mass flow rate leads to a rise in CHTC. Furthermore, decreasing the outgoing heat flux reduces CHTC and amplifies the temperature at the outlet. The sensitivity analysis indicates that OT is most sensitive to a slight change in the mass flow rate and least sensitive to change in the rotor speed. Moreover, an optimal Pareto front with 35 non-dominated optimal points is obtained.