Heat exchangers are devices that typically transfer heat between two fluids. The performance of a heat exchanger such as heat transfer rate and pressure loss strongly depends on the flow regime in the heat transfer system. In this paper, we present a density-based topology optimization method for a two-fluid heat exchange system, which achieves a maximum heat transfer rate under fixed pressure loss. We propose a representation model accounting for three states, i.e., two fluids and a solid wall between the two fluids, by using a single design variable field. The key aspect of the proposed model is that mixing of the two fluids can be essentially prevented. This is because the solid constantly exists between the two fluids due to the use of the single design variable field. We demonstrate the effectiveness of the proposed method through three-dimensional numerical examples in which an optimized design is compared with a simple reference design, and the effects of design conditions (i.e., Reynolds number, Prandtl number, design domain size, and flow arrangements) are investigated.

热交换器是通常在两种流体之间传递热量的装置。热交换器的性能，例如传热速率和压力损失，在很大程度上取决于传热系统中的流动状态。在本文中，我们提出了一种基于密度的双流体换热系统拓扑优化方法，该方法可在固定压力损失下实现最大传热速率。我们提出了一个表示模型，该模型通过使用单个设计变量字段解决了三种状态，即两种流体以及两种流体之间的固体壁。所提出的模型的关键方面是，基本上可以防止两种流体的混合。这是因为由于使用单个设计变量字段，所以固体始终存在于两种流体之间。