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.
Aerodynamics characteristics of a vertical axis vane type wind turbine
This research work has been carried out to study the aerodynamic characteristics and to analyze the effect on an equally spaced vertical axis four, five and six bladed vane type rotor. The aerodynamic characteristics i.e. torque coefficient, drag coefficient etc. of vertical axis vane type rotor have been studied in this present research work by measuring the pressure distribution on the blade surfaces at various rotor angles. The experiments have been carried out at a Reynolds number of 1.65 x 10 in a uniform flow jet produced by an open circuit wind tunnel. The pressure measurements have been made at 8 tapping points on each blade of the vane rotors. Pressure on the convex and concave surfaces have been measured for every 10 interval of rotor angle up to 3600 angle of rotation. The data obtained experimentally has presented in terms of non-dimensional coefficients. To calculate drag force and torque in non-dimensional form, computer based software has been used and the output have been subsequently plotted and analyzed. Aerodynamic characteristics on individual and group of four, five, six blades have also been determined in the present work. A quasi-steady approach has been applied for studying the dynamic performance of the rotor at different rotor angle using the static drag and torque coefficients. Power coefficient versus tip speed ratio curve for four, five and six bladed vane type rotor has also been drawn. Power coefficient versus tip speed ratio of the present measurement and the previous researcher's works has plotted on the same graph for comparison. This method results in a reasonable agreement with the previous measurement.
Parboiled rice effluent: A wastewater niche for microalgae and cyanobacteria with growth coupled to comprehensive remediation and phosphorus biofertilization
Abstract The potential of microalgae and cyanobacteria for bioremediation of wastewater by nutrient uptake combined with simultaneous biomass production is a well recognized perception of today's world. The present study illustrates the treatment of a highly polluted wastewater generated during parboiling of paddy in rice mill industries, widely operational in developing countries where rice is the staple food crop, with the help of microalgal and cyanobacterial isolates capable of growing at high rates in parboiled rice mill effluent (RME). This endeavor leads to comprehensive bioremediation of the said effluent and subsequent use of the harvested biomass as slow release phosphorus biofertilizers and the treated effluent for crop irrigation. The RME-acclimatized algal consortium demonstrated highest growth in terms of fresh weight and greatest remediation efficiency at the end of 36 days' treatment of RME, with 93.9% phosphorus and 100% ammonia-nitrogen removal, 98.7%, 91.6% and 93.5% reduction in biological oxygen demand, chemical oxygen demand and total dissolved solid, respectively, and an increment of 186 ± 0.3 mg L − 1 dissolved oxygen, bringing down the pollutants level well below the discharge limits suggested by Central Pollution Control Board, India. Additionally, microalgae in the consortium aggregated in clumps spontaneously in presence of the filaments of Phormidium sp. facilitating easy harvest. The RME-acclimatized algal consortium demonstrated highest accumulation of polyphosphate (poly-P) (0.76 ± 0.01% of dry weight) as well as highest release of phosphorus in non-sterile soil emphasizing the essential role of soil phosphorus solubilizing organisms to leach soluble phosphorus from the insoluble poly-P present in the biomass. The rice seedlings watered with treated RME also showed improved growth effect on shoot height and leaf width. The study results establish the suitability of RME as an excellent growth media for microalgae and cyanobacteria.