The effect of blade slots on flow behaviour in a fan impeller Adam Pieruszka, Tomasz Siwek, Wojciech Kalawa, Łukasz Lis, Sebastian Stefański and Karol Sztekler EPJ Web Conf., 213 (2019) 02067 Published online: 28 June 2019 DOI: 10.1051/epjconf/201921302067