Fluid Flow Investigations of Bionic Absorbers Made From Aluminium and Steel
Abstract
Challenges of future solar collector development are cost reduction, industrial production methods as well as flexibility with respect to different designs. In contrast to conventional sheet-and-tube constructions, metal forming processes offer flexible, hydraulically and thermally optimized designs without additional costs. Among those processes aluminium roll-bonding as well as partial roll cladding in combination with hydroforming of steel are promising technologies. Solar collectors containing absorbers with a bionic FracTherm® channel design are currently being developed within the European project BIONICOL (aluminium roll-bond) and a German research project (partially roll cladded and hydroformed steel absorbers with a multi-layer configuration). This paper focuses on fluid flow investigations considering the special shape of FracTherm® channel designs which can be produced using the mentioned production technologies (among others). CFD simulations were carried out in order to learn more about three-dimensional flow phenomena and to calculate pressure drop and flow distribution. Moreover, a fluid dynamics test facility for both flow visualization and measurements was developed. Pressure drop measurements and visualizations of the flow distribution in large absorbers were carried out.