Performance of a stationary vertical axis vane type rotor tested in a wind tunnel
This paper reports the performance of an equally spaced vertical axis vane type rotor tested in a wind tunnel. The aerodynamic characteristics i.e. torque coefficient, drag coefficient etc. of a stationary vane type rotor have been studied in this research work by measuring the pressure distribution on the blade surfaces at various rotor angles. The experimental investigation was performed on four bladed vertical axis vane type rotor in a uniform flow jet produced by an open circuit wind tunnel. It has been observed that the static torque varies at different rotor angles. Total static torque coefficient at different rotor angles curve repeats from 0° to 80°, 90° to 170°, 180° to 260° and 270° to 350° angle of rotation. A quasi-steady approach was applied for the prediction of dynamic performance of the rotor using the static drag and torque coefficients. This method results in a fair agreement with the measured power coefficient.
Velocity measurements and numerical calculations of flow fields in and around Savonius rotors
Abstract The flow fields in and around Savonius rotors at various overlap ratios have been investigated to clarify the effect of overlap on the flow mechanisms. Measurements of phase-averaged velocity distributions were carried out using particle imaging velocimetry with a conditional sampling technique, and the results were compared with numerical calculations by a discrete vortex method. The measured velocity distributions indicate clearly the effect of the overlap both on the flow through the overlap and on the formation region of the vortices downstream of the rotor. Although numerical calculations can predict the basic features of the variation of the flow field with rotor angle, the flow field of a stationary rotor, especially at small rotor angles, is not well reproduced in the calculations, suggesting that the assumptions of flow separation at the tips of the blades and the two-dimensionality of the flow are invalid. However, the correlation with measurement is improved for the flow over a rotating rotor.
Experimental Study on Acoustic Agglomeration of Fine Particles from Coal Combustion
The removal of fine particles in coal-fired fumes was experimentally studied based on acoustic agglomeration. An experiment facility was designed and set up. In this facility, a fluidized bed coal combustor was used as fume generator, and an Electrical Low Pressure Impact or (ELPI) was used to measure the fine particle concentration and size distribution in the fumes. The results show that under the effect of high intensity sound waves, there is good performance to remove fine particles in coal-fired fumes, which with a number mean diameter of 0.07μm. Especially, under the conditions of the frequency of 1 000Hz and the sound intensity of 161.5dB, the number concentration of 0.0233~9.314μm particles decreased by 85.2%, and their mass concentration decreased by 92.5%.