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

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. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

The thermohydraulic attributes of a biologically produced nanofluid with graphene nanoplatelets inside a pipe with twisted conical strip inserts are optimized by adjusting the slant angle, geometry angle, and pitch. The genetic algorithm and compromise programming method are used to increase the Nusselt number and decrease the friction coefficient. In cases where the priorities of the friction coefficient and Nusselt number are similar, larger slant angles and smaller geometry angles should be utilized to achieve the optimal point where Nusselt number and friction factor increase significantly compared to a plain tube.