Reduced-order turbulent flow solver to simulate streamwise periodic fins with iso-thermal walls

Abstract

Assessment of the thermo-hydraulic performance of heat exchangers using computational fluid dynamics is a challenging task. The intricate geometries of a heat exchanger require a fine discretization of the flow passage, which consequently leads to high computational costs. A streamwise periodic flow model can significantly reduce this cost, particularly for heat exchangers featuring repeating structures. This manuscript presents the streamwise-periodic turbulent source terms for flows in channels with isothermal walls, along with the implementation of the corresponding periodic flow solver in the open-source CFD-Suite, SU2. The accuracy of the implemented solver was verified by comparing its predictions against those of a full fin array simulation for the test case of offset circular fins. The results show that the streamwise periodic flow solver accurately reproduces the solutions of the full array simulation under both laminar and turbulent flow conditions.

Figures (13)

• Figure 1: Illustration of the simulation domain considered for the offset pin-fin array, where $r$ is the radius of the pin-fins.
• Figure 2: Illustration of the unit cell flow domain representing the offset pin-fin array, where $r$ is the radius of the pin-fins.
• Figure 3: Variation of the metrics of interest ($\lambda_\mathrm{L}$ & $\Delta p$) with grid density ($\xi_{i}$), in the case of (a) laminar (Re$= 100$) and (b) turbulent (Re$= 10000$) flows.
• Figure 4: Mesh selected for the numerical simulations.
• Figure 5: Variation of flow properties at the inlet of each unit cell according to the results of the fin array simulation for $Re$=100: streamwise velocity (left), pressure (center) and temperature (right).