A combined multi-criterion optimization to determine optimum geometrical parameters for flow of an ecofriendly graphene-based nanofluid inside tube enhanced with twisted conical strip inserts

Abstract

Thermohydraulic attributes of a biologically produced nanofluid containing graphene nanoplatelets inside a pipe fitted with twisted conical strip inserts are optimized. The slant angle, geometry angle, and pitch are the geometrical parameters, which are optimized to reach highest Nusselt number and lowest friction coefficient. Genetic algorithm in combination with compromise programming method is used. The slant angle and pitch have more profound impacts on Nusselt number in comparison with their influence on friction factor, while the geometry angle has a greater effect on the friction factor. In the case that the friction coefficient and Nusselt number have rather similar priorities, one should utilize the larger slant angles and smaller geometry angles. Under similar priority of two outputs, at the relevant optimum point, Nusselt number and friction factor respectively increase by about 40.4% and 2.2 times relative to those in the plain tube.