Application of Modern Additive Manufacturing Techniques in the Preparation of Flow Models for Optical Flow Measurement Methods

¹ CTU in Prague, Faculty of Mechanical Engineering, Department of Fluid dynamics and Thermodynamics, Technická 4, 160 00 Prague, Czech Republic
² Charles University and Military University Hospital, First Faculty of Medicine, Department of Neurosurgery and Neurooncology, U Vojenské nemocnice 1200, 169 02 Prague 6, Czech Republic

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

This study presents an experimental methodology for fabricating transparent flow models tailored for Particle Image Velocimetry (PIV). The approach is based on 3D printing complex internal geometries from acrylonitrile styrene acrylate (ASA), a material that can be smoothed using acetone vapours to enhance optical clarity. The ASA models are embedded in Sylgard 184 silicone elastomer and then dissolved in acetone to leave optically transparent flow channels. To evaluate surface treatment effects, stenosis models were divided into sections and subjected to different combinations of sanding and acetone smoothing. Additionally, the method was extended to anatomically accurate nasal cavity models derived from computed tomography (CT) scans. While ASA offers improved surface quality and compatibility with acetone smoothing, the dissolution of complex structures proved time-consuming, taking over 40 days in the nasal model case. Simpler geometries dissolved within two days. Optical clarity and refractive index matching with a glycerol–water solution were sufficient for PIV, though minor mismatches were observed. The findings demonstrate the method’s potential for constructing anatomically realistic, PIV- compatible models, while highlighting trade-offs in preparation time and solvent use. Future work should explore hybrid approaches combining ASA and water-soluble materials like PVA to optimize fabrication efficiency.