Heat Exchanger with Baffle Cut: Mixture Multiphase Model

Heat Exchanger with Baffle Cut and Mixture Nanofluid — ANSYS Fluent CFD Simulation

Description

This project presents a CFD investigation of the combined effects of baffle configuration and nanofluid application on shell-and-tube heat exchanger performance. The simulation examines a shell-and-tube exchanger incorporating two heat-transfer-enhancement techniques at once: strategic baffle placement and an Al₂O₃–water nanofluid as the working medium. The nanofluid improves thermal performance by raising the effective thermal conductivity without a significant viscosity penalty, while the baffles create beneficial flow patterns and extend the shell-side flow path — together achieving superior heat transfer while maintaining acceptable hydraulic performance. Within the Nanofluid: Beginner CFD Training Package, this project combines the mixture nanofluid model with baffle-cut geometry, building on the earlier heat-exchanger cases toward more advanced enhancement strategies.

Methodology

The heat exchanger has a shell of 1 m diameter and 4.5 m length, carrying the Al₂O₃–water nanofluid as the cold shell-side stream, with water as the hot tube-side stream through 0.15 m diameter tubes of 3 m active length. Four baffles of 0.7 m length are arranged on the shell side, with 0.15 m shell-side and 0.3 m tube-side connection nozzles. The domain — shell-side flow path with baffles, tube-side flow path, and solid tube walls — is meshed in ANSYS Meshing with 450,980 elements, with fluid–solid interfaces defined for conjugate heat transfer. The nanofluid is modeled with the Mixture multiphase model, with water as the continuous phase and Al₂O₃ particles as the dispersed phase, capturing interphase drag, particle distribution, and thermal effects. The Al₂O₃ nanoparticles have a thermal conductivity of 40 W/m·K and a density of 3970 kg/m³, with effective properties calculated from mixture theory. A pressure-based coupled solver is used with second-order discretization, the k-ε turbulence model with standard wall functions, and a steady-state solution.

Analysis

The results are visualized through temperature contours that reveal the thermal gradients and quantify the heat-transfer enhancement over conventional fluids, isolating the contribution of the nanofluid's raised thermal conductivity. Streamline analysis shows the complex flow patterns induced by the baffles, identifying recirculation zones that promote mixing and the flow acceleration in the baffle-restricted areas. Together these clarify how the baffles and nanofluid enhance heat transfer synergistically — beyond what either could achieve alone. From these results you can draw design guidance on optimal baffle placement with nanofluids and on balancing thermal enhancement against pumping power. By the end of this project, you'll be able to set up a shell-and-tube exchanger with baffles, model a nanofluid with the Mixture multiphase model and conjugate heat transfer, and evaluate the combined heat-transfer enhancement from the temperature and flow fields.