SECONDARY FLOW MEASURING AT THE RADIAL FAN ENTRANCE

Abstract – Analyze is given of different measuring meth-ods relating to the prerotation flow in the entrance pipe of the radial pump. The appearance of the prerotation flow is a result of complicated fluid flow model, which appears as a consequence of the pump operating out of design point and reduce the pump efficiency. The goal of this contribu-tion is in estimating the adequate measuring method, tak-ing into account the inconvenience of conventional Laser – Doppler anemometry. Therefore, two measuring meth-ods – multiblade (ASB) and single blade anemometer (ASSB) are introduced, analyzed and compared with well known 2 channel hot wire anemometry (HWA). The ad-vantages of the introduced measuring system- ASB are in its simple construction and simple use and its low price. Direction and the swirl flow intensity in the entrance pipe of radial pumps and fans, using this method, could be measured