Computational fluid dynamics has become an effective tool for analyzing complex fluid flow and heat transfer processes in thermosyphon systems. Most previous studies on thermosyphon solar collectors have mainly focused on the evaporator section, while comparatively limited attention has been given to the condenser manifold despite its critical role in heat removal and overall system efficiency. In this study, a three-dimensional numerical investigation is conducted to analyze fluid flow and heat transfer within the water manifold of a two-phase closed thermosyphon collector. The system operates with Fe₃O₄ nanofluid in the evaporator section under externally applied magnetic field strengths of 150, 350, and 550 G, with nanoparticle concentrations of 4, 6, and 8 wt%. The effect of magnetically enhanced evaporation is incorporated indirectly through the inlet boundary conditions of the condenser section, enabling evaluation of its influence on heat removal performance. The governing equations for laminar forced convection and heat transfer are solved using the SIMPLE algorithm implemented in FORTRAN-90. The results demonstrate that magnetic field-assisted evaporation significantly enhances condenser thermal performance, as evidenced by increased outlet water temperature and improved heat transfer characteristics. A maximum outlet temperature of 40.2 °C is achieved at 550 G, while optimal performance occurs at a flow rate of 0.3 L/min. Validation against experimental data shows good agreement, with a maximum deviation of approximately 7%, confirming the reliability of the numerical model. The study provides new insight into the coupled thermal interaction between evaporator enhancement using magnetic nanofluids and heat removal in the condenser.
Dawood et al. (2026) studied this question.