Topology optimization of two-fluid turbulent heat exchangers: A Darcy flow-based multifidelity approach

TL;DR

This paper introduces a multifidelity topology optimization method for two-fluid turbulent heat exchangers, combining low- and high-fidelity models to design efficient, high-performance heat exchange structures.

Contribution

The paper develops a calibrated Darcy flow-based low-fidelity model integrated into a multifidelity optimization framework for turbulent heat exchanger design.

Findings

Optimized designs achieved up to 22% higher performance evaluation criterion (PEC).

Designs enhanced heat transfer while controlling pressure drops.

Multifidelity approach effectively balances accuracy and computational efficiency.

Abstract

This paper presents a topology optimization method for designing two-fluid heat exchangers under turbulent conditions using a Darcy flow-based low-fidelity (LF) model. The LF model is calibrated against a high-fidelity (HF) model based on the Reynolds-averaged Navier-Stokes (RANS) equations to increase the accuracy of predictions for fluid flow and heat transfer characteristics. Since the discrepancies between the LF and HF models can be significant, particularly for pressure drops, a multifidelity topology optimization framework is adopted to leverage the strengths of both models. Using the calibrated LF model, we perform topology optimization for various inlet velocities in the boundary conditions and trade-off parameters in the objective function to obtain diverse optimized designs. The optimized designs are then evaluated using the HF model to assess their performance with higher accuracy. The results demonstrate that the optimized designs significantly improve overall heat transfer coefficients while maintaining manageable pressure drops, achieving up to a 22% higher performance evaluation criterion (PEC) compared to a reference design enhanced by conventional twisted tape insertion. The improvements are attributed to the optimized configurations that promote enhanced fluid mixing and increased surface area for heat exchange, yet maintain streamlined flow paths to minimize pressure losses. Overall, the proposed topology optimization method using the Darcy flow-based LF model proves effective in designing high-performance double pipe heat exchangers, showcasing the potential of the multifidelity approach in overcoming the challenges of optimizing heat exchangers under turbulent flow conditions.