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Experimental Study of Air Flow in a Hydro Power Generator Model

Erwin Hartono
Göteborg : Chalmers tekniska högskola, 2011. Diploma work - Department of Applied Mechanics, Chalmers University of Technology, Göteborg, Sweden, ISSN 1652-8557; 2011:51, 2011.
[Examensarbete på avancerad nivå]

Air cooled electric generators have been studied for a long time, but there is still a lack of knowledge about the details of the air flow in such machinery. In this work, a generator ventilation model was specially designed and constructed as a 1:2 model of an existing generator model in Uppsala University. Full flow Reynolds number similarity is achieved by increasing the rotation speed of the model generator. The rotor and the stator were built with rapid-prototyping techniques that could resolve the complex geometry with high accuracy. The manufacturing process also allows the inclusion of pressure taps, making it possible to measure the wall static pressure in the most interesting region. A sector of the stator was built in plexi-glass for the PIV measurements. Six configurations were investigated: two different stators with three different rotor fan blades. The rotational speed was kept constant for all cases to maintain the same Reynolds number. The static pressure at the stator coils, stator inner and outer walls, and the total pressure at the outlet of the stator channels were measured. Pressure transducer together with scanivalve were used to measure the static pressure around the coil. A custom made rake was built to measure the total pressure at the outlet of the channel. Mass flow was estimated by integrating the total pressure data from the outlet. Two static pressure taps at the top of enclosure wall was made to estimate the flow angles. Around the coil the air flow has a large tangential component when entering the stator channels. The air flow was estimated to be swirl due to high flow angle. The static pressure at the stator inner wall increases as the air flows axially in the space between the rotor and stator. Half of the stator cooling channel was occupied by recirculation region. Estimated mass flow has approximately half the value compared to numerical calculation of 100% scale generator in Uppsala in accordance with design expectations.

Nyckelord: Experimental, Hydro Power, Generator, Air-Flow

Publikationen registrerades 2011-10-26. Den ändrades senast 2013-04-04

CPL ID: 147717

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