A computational fluid dynamics study by conjugate heat transfer in OpenFOAM: A liquid cooling concept for high power electronics

•A CHT study with CFD of a liquid cooling heat exchanger is performed using OpenFOAM.•Simulation results were compared to experiments where possible.•The simulated temperature levels depend on the used turbulence model due to boundary layer modeling.•The use of CHT is noted to be significant for realistic modeling of cooling localized heat sources. A conjugate heat transfer (CHT) study of a liquid cooling heat exchanger is carried out using the open source computational fluid dynamics (CFD) library OpenFOAM. The heat exchanger was 3D printed using aluminium and experimentally verified by temperature probing and thermal imaging. The functionality of the heat exchanger in cooling localized heat sources is demonstrated. Three different turbulence models were utilized including k-ω shear stress transport (SST) model, the standard k-ε model and large-eddy simulation (LES). The numerical results indicate that the k-ω SST and LES models produced similar results in terms of flow structures and temperature levels while the k-ε model deviated from the two other models. The scalability of the heat exchanger was numerically demonstrated by comparing the flow uniformity by varying the inlet Reynolds number between 4960 and 14880. The conclusions of the paper consists of the following main results. (1) The numerical results indicate that the flow uniformity in the channels is noted to be affected by the flow structures before and after the fin system. (2) The simulated hot-spot temperatures were noted to be relatively sensitive to the predicted flow laminarization inside the channels. (3) The heat exchanger was shown to be functional and to maintain cool surface temperatures in the simulations and the experiments. Additionally, the used CHT solver in OpenFOAM is tested and verified in different ways.