Numerical simulation of thermal performance nanofluid in flat plate solar collector equipped with twist strip

The aim of this study is to increase the thermal performance of the flat plate solar collector by placing a twisting tape inside its tube and using aluminum-oxide water nanofluid. The use of twisting tape increases the contact surface of the fluid with the wall and creates a rotating flow. In this present numerical study, a twisting strip with different dimensions, along with aluminum-oxide water nanofluid, has been evaluated under the influence of a constant heat flux in the Reynolds number range of 4000 to 20000. For the numerical solution of this article, Fluent commercial software and k-ε turbulence model is used. According to the conducted tests, the numerical results are such that placing the twisting tape in the flat plate solar collector creates a rotating current and improves fluid mixing. As a result of increasing the diameter ratio and twist ratio of the tape, the heat transfer rate increased and on the other hand, it increases the pressure drop and consequently the friction coefficient. The coefficient of thermal performance has a higher value in lower Reynolds numbers, so that the highest value of the coefficient of performance is 1.08 in diameter ratio 0.014, twist ratio is 7 and the lowest Reynolds number is 4000.