Optimized design of solar collector using new geometry of fins in tube

In this study, a three-dimensional CFD analysis is conducted to evaluate the thermo-hydraulic performance of a linear parabolic trough solar collector receiver tube equipped with twisted and trapezoidal fins. A silver/water nanofluid is employed as the working fluid to enhance heat transfer. The effects of nanoparticle volume fraction, inlet mass flow rate, and fin geometry on thermal and hydraulic behavior are systematically investigated. Simulations are performed using ANSYS Fluent 2024 R1 with the finite volume method and SIMPLE algorithm. Second-order upwind discretization is applied to improve numerical accuracy. Nanofluid flow is modeled using an Eulerian–Lagrangian approach with a discrete phase model incorporating Brownian motion and thermophoresis. A uniform absorbed heat flux of 10,000 W/m² is imposed on the receiver tube wall. The inlet mass flow rate ranges from 0.01 to 0.12 kg/s, while nanoparticle volume fraction varies up to 2%. Results show that increasing mass flow rate and nanoparticle concentration enhances convective heat transfer. However, these improvements are accompanied by higher pressure drop and friction factor. The twisted fin configuration exhibits superior thermal performance due to strong secondary flows and swirl generation. The performance evaluation criterion confirms the effectiveness of the proposed fin geometries in improving overall thermal efficiency.