A Radiator CFD simulation is a computer model of an important heat transfer system. Aluminum radiators are used in cars, air conditioning, computers, and factories where cooling is very important. These Heat Exchanger Simulation Fluent studies help engineers design better cooling systems. An Aluminum Radiator CFD analysis shows how hot liquid flows through tubes and how heat moves through aluminum parts. This Conjugate Heat Transfer Analysis is essential because it models both the fluid flow and the solid aluminum at the same time. The Automotive Cooling System CFD simulation captures complex physics like turbulent mixing, heat conduction through aluminum fins, and convective cooling. Engineers use Thermal Management CFD to optimize fin design, tube size, and flow rates. This ANSYS Fluent modeling includes advanced heat transfer calculations and material properties to predict cooling performance accurately.

Figure 1: The detailed 3D model of the Aluminum Radiator CFD system showing multiple parallel tubes and aluminum fins for enhanced Heat Exchanger performance.

Simulation Process: Fluent Setup, Conjugate Heat Transfer Modeling with Custom Coupling

To perform this Aluminum Radiator Fluent study, we first designed a detailed 3D model with multiple parallel tubes and aluminum fins. This geometry creates an efficient heat exchanger configuration with upper and lower manifolds connected by aluminum tubes that carry the cooling fluid. The aluminum fin structure provides extended surface area for better Heat Dissipation Modeling. We used ANSYS Fluent Meshing to create a high-quality computational mesh with proper resolution in critical regions including fluid passages, aluminum-fluid interfaces, and fin surfaces where heat transfer occurs.

In the ANSYS Fluent solver, we used the pressure-based solver with the energy equation enabled to model conjugate heat transfer between the aluminum material and working fluid. The aluminum thermal conductivity was set to 237 W/m·K to accurately represent heat conduction through the solid parts. The most important innovation in our setup was creating a custom expression that automatically applies the outlet temperature from the upper tube as the inlet temperature for the lower tube. This creates a realistic coupled thermal system that represents actual radiator operation. For boundary conditions, we set the cooling water inlet at 70°C through a mass flow inlet, applied pressure outlet conditions, and used conjugate heat transfer at all aluminum-fluid interfaces.

Post-processing: CFD Analysis, Multi-Stage Cooling Performance and Thermal Efficiency

The temperature distribution contours in Figure 2 provide clear evidence of the multi-stage cooling process in our aluminum radiator system. The upper tube receives hot water at 70°C at the inlet and successfully reduces the temperature to 66.16°C at the outlet. This temperature reduction of 3.84°C in the upper tube demonstrates effective heat rejection from the hot coolant to the aluminum structure through conjugate heat transfer. The cross-sectional analysis in Figure 3 reveals the thermal coupling mechanism, showing smooth temperature transitions between water and aluminum interfaces, which confirms our CFD model’s accuracy.

Figure 2: Temperature distribution contours from the Radiator Fluent simulation, showing thermal performance and heat dissipation through the aluminum structure.

Figure 3:  Cross-sectional temperature analysis from the Conjugate Heat Transfer Analysis, revealing thermal coupling between water and aluminum components.

The velocity contours in Figure 4 show fully developed flow patterns with maximum velocities reaching approximately 0.07 m/s at tube centers and lower velocities near walls due to viscous effects. This parabolic velocity profile is characteristic of laminar flow in circular tubes, which is typical for radiator applications. Most importantly, our custom coupling expression successfully models the realistic flow path where the lower tube receives water at 61.35°C from the upper tube outlet. The water temperature further decreases to 60.04°C at the lower tube outlet, achieving an additional temperature drop of 1.31°C. The total cooling achieved is 9.96°C (from 70°C to 60.04°C), representing significant heat rejection and demonstrating excellent thermal effectiveness. The aluminum fins and tube walls show intermediate temperatures between hot water and ambient conditions, indicating proper heat conduction through the aluminum material with its high thermal conductivity of 237 W/m·K. The most important achievement of this simulation is its successful implementation of a custom coupling expression that accurately models the realistic multi-stage cooling process, achieving a total temperature reduction of 9.96°C and demonstrating the superior thermal performance of the aluminum radiator design for automotive and industrial cooling applications.

Figure 4: Velocity contour from the Automotive Cooling System CFD simulation, showing water flow patterns and fully developed flow in radiator tubes.