Optimizing the macrostructure of 3D-printed pipe surfaces to improve cleanability

Efficient heat transfer is essential for the economically sustainable operation of heat exchangers. Therefore, the internal flow is influenced systematically in various ways, for example by introducing macrostructures on the pipe surface. Since these measures may negatively affect the cleanability of the heat exchanger, it is necessary to investigate not only the increase in heat transfer, but also their impact on cleaning processes. For this purpose, the cleaning of sour milk in dimple-structured pipes is investigated experimentally. Both macroscopic and microbial cleaning tests are conducted to assess the influence of the surface’s macrostructure on cleanability. Two geometry variations of dimple-structured pipes are investigated and compared to a straight pipe Although fouling is enhanced by the dimple structures, a higher macroscopic cleaning rate can be achieved with the optimized dimple. Moreover, the residual microbial contamination decreases significantly due to the introduction of dimples. All in all, the cleaning experiments confirm the positive influence of the dimple structures on cleanability.