Additively Manufactured Heat Exchangers- Development and Testing

Sammanfattning: Heat exchangers are important devices in many applications. Extensive work is done in optimization, but the overall designs are often one of the conventional varieties such as plate or shell-and-tube heat exchanger. These are constrained by their manufacturing, for example the use of construction material such as sheet metal and cylindrical pipes. The current progress in additive manufacturing has the potential to disrupt convention, as it allows complex shapes better suited to the nature of fluid flow. The intersection between heat exchangers and additive manufacturing has been explored in this thesis. The structures known as Triply Periodic Minimal Surfaces were found to have special potential because of their suitability for both heat transfer and additive manufacturing. Specifically, the “Schwarz D” and “Schoen G” varieties were used. A method for enclosing these structures according to the internal channels was developed and a manifold was designed to allow full counter current flow. Two complete heat exchanger variations were produced in the material AlSi10Mg, evaluated experimentally and simulated using computational fluid dynamics. This thesis suggests equal usefulness of the two proposed designs for heat exchanging applications, as well as demonstrates their manufacturability. The inner structure was found to provide good mixing and an even flow distribution, while the manifold design requires further development to lower pressure loss.