JBASV8N2A55-Micro Vertical Axis Wind Turbine Design Integrated with Wind Accelerating Techniques

Journal of Basic and Applied Sciences - Volume 8 Number 2

Micro Vertical Axis Wind Turbine Design Integrated with Wind Accelerating Techniques
Abdul Latif Maghanhar, Saleem Raza Samo and Altaf Hussain Rajpar

http://dx.doi.org/10.6000/1927-5129.2012.08.02.55

Abstract: Power generation from natural wind is the crucial issue due to rapid depletion of non-renewable energy resources and their pollution demerits. Most observers agreed that long-term economic growth will require technical innovation to make wind energy more competitive with other forms of energy. One among the key trends is the push to improve productivity. Vertical axis wind turbines are capable of extracting power from wind regardless of direction of natural wind flow. Very less work is devoted to improve the characteristics of wind to make it more useable for power generation. Major portion of the research is related to the wind energy system design that caters the domestic needs. A micro vertical axis wind turbine system with integrated wind accelerating techniques is proposed. At the outer of the turbine a wind accelerating convergent duct with larger wind area is proposed, that will perform as a nozzle action to accelerate the natural wind when it strikes on the front half portion of the turbine blades. Proposed micro wind turbine is also integrated with satellite dish type parabolic structure, mounted at the top of the turbine. The parabolic concentrator surface is coated with sun rays reflecting mirrors, sunlight striking on paraboliod surface is directed to words a heat absorbing hollow cylinder, erected at the center of the paraboliod concentrator. Hollow cylinder is the path channel for air leaving the turbine. Air molecules passing through this channel will be heated up, moving rapidly up word creating momentum in air leaving from the turbine. Design of the proposed vertical axis wind turbine system integrated with wind accelerating techniques and experimental study of wind accelerating duct composed of various section is reported in this research work.

Keywords: Vertical Axis Wind Turbine, Converging duct, Solar-thermal air heating.

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The Effect of Grain Size on Radon Exhalation Rate in Soil Samples of Dera Ismail Khan in Pakistan

Tabassum Nasir and Nisar Ahmad

http://dx.doi.org/10.6000/1927-5129.2012.08.02.29

Abstract: Radon concentration and its exhalation rate has been measured from twenty five soil samples collected from seven different locations of Dera Ismail Khan, in the north west of Pakistan. These samples were crushed after drying and passed through sieves with different sizes of pores to get three grain sizes, £0.595 mm, 0.595-2.00 mm and 2.00-4.00 mm of soil. CR-39 based NRPB (National Radiological Protection Board) radon dosimeters have been used to measure the radon concentration and exhalation rates. The maximum average value of radon exhalation rate has found to be: (3.57±0.38) Bq m^-2 hr^-1 in the samples having grain size 2.00-4.00 mm and the minimum as: (2.21±0.26) Bq m^-2 hr^-1, in the samples with grain size £ 0.0595 mm. This indicates that the radon exhalation rate increases with the grain size. The maximum average value of radon exhalation rate has been found in samples collected from river side where soil texture is silty clay loam. The obtained values of radon exhalation rate for all the samples are well below the world average value of 57.60 Bq m^-2 hr^-1.

Keywords: Radon concentration, Radon exhalation rate, grain size, soil texture.