This paper presents an experimental study of the liquid disintegration process on an atomizer with two counter-rotating wheels by high-speed imaging. The process was investigated for a wide range of wheel rotational speeds, liquid flow rates and impingement positions. Compared to flat disc and cup atomizers operating at similar Weber numbers, proposed atomizer design is capable of producing much finer droplets in the ligament formation mode (mean diameter under 0.15 mm when We = 10(6)) and at a significantly larger liquid throughput. Despite the atomizer gap flow complexity, approximation of mean liquid trajectories with tangent lines proved to be fairly accurate. We were able to identify two main challenges in atomizer operation, namely the occurrence of hydraulic jump upon liquid impingement causing the formation of large droplets, and escaping of the liquid spray through the wheel gap. Nevertheless, both issues can be largely mitigated by optimization of atomizer geometry and operating parameters. (C) 2020 Published by Elsevier B.V. on behalf of Institution of Chemical Engineers.