A CFD investigation was carried out to compare the thermal performance of the 1EHT-1 and 1EHT-2 tubes with a smooth surface tube using R410A at 311K as working fluid. These tubes have enhanced heat transfer area generated by a series of dimples/protrusions and petals distributed over its surface. All the stages of this simulation were conducted using Ansys Fluent. Initially, the physical model of the fluid domain was developed using the Design Modeler module, with an internal tube diameter of 8.32mm, and then imported to the meshing module for the griding process. To ensure accuracy in the results, the mesh average orthogonal quality was kept above 0.7, with the minimum orthogonal quality higher than 0.1. For the numerical simulation, SST k-omega model was used, with Reynolds number ranging from 16000 to 35000. The results of the heat transfer coefficient were validated based on previous experimental work. As expected, at the lowest Reynolds number tested, the heat transfer coefficient for the 1EHT-1 tube was 1097.5 W.K−1.m−2, followed by 1058 W.K−1.m−2 for the 1EHT-2 and nearly 846 W.K−1.m−2 for the smooth tube. When compared with the experimental results, a good agreement was observed, and the HTC relative error (RE) for all tubes tested was below 10%. It is possible to conclude that the CFD model used here presents as powerful tool to simulate and predict heat transfer with good accuracy, allowing optimization in heat exchangers design and operational parameters.

This content is only available via PDF.
You do not currently have access to this content.