S. A. Sharifian

Bio: S. A. Sharifian is an academic researcher from University of Southern Queensland. The author has contributed to research in topics: Pressure sensor & Wind direction. The author has an hindex of 2, co-authored 4 publications receiving 12 citations.

Numerical investigation of performance of a new type of savonius turbine

Abstract: Wind energy is non-polluting and is freely available in many areas and is gaining popularity among researchers. Among wind turbines, Horizontal Axis Wind Turbines (HAWT) are more common compared to Vertical Axis Wind Turbines (VAWT) mainly because of their higher efficiency. However, Savonius turbine of VAWT type has many advantages over others such as simplicity in construction, lower cost of production, constancy of the output power regardless of the wind direction, and good starting torque at low wind speed. It is conceived that the efficiency of the Savonius turbines can be increased using industrial wasted heat primarily due to their structural similarity with the split chambers which are often used to induce fire-whirls in laboratories. This work deals with a basic design of such combined configuration and compares its efficiency with a conventional Savonius turbine. The computational results show that the new design has a higher steady state angular velocity as well as higher coefficient of power than the conventional Savonius turbine.

Reducing the mechanical hysteresis problem in optically addressed diaphragm pressure sensors

Abstract: Mechanical hysteresis problems associated with pressure sensors based on interferometric measurements of diaphragm deflection are discussed. The source and importance of each contribution to the net hysteresis is calculated and compared with experimental results. Possible methods to decrease hysteresis effects are presented. Based on these suggested methods, new sensors have been manufactured and their hysteresis evaluated. The results demonstrate that significant reductions in hysteresis can be achieved with minimum cost. Future sensor development will focus on materials selection and manufacturing methods to fully realize these improvements.

The effect of inlet velocity and temperature on the strength of the swirling induced by a split channel: a CFD approach

Abstract: Due to the increase of energy cost, natural heat resources and industrial waste heat have been considered as potential energy resources and has been the centre of attraction among many researchers in recent years. Limitations of the use of these freely available energy resources arise primarily from the engineering cost/efficiency challenges. Some researchers have focused on improving the efficiency of existing techniques to utilize these energy resources. Some other researchers have focused on finding new techniques of extracting energy from these heat resources. The ratio of the cost/efficiency index can be reduced not only by increasing the efficiency, but also by reducing the engineering cost. This research deals with an innovative low-cost technique to produce swirling flow by industrial wasted hot air which is already in use to induce fire-whirl by burning fuel in the laboratory. The configuration consists of two identical half cylinders which are placed off-centre. Previous studies show such a simple configuration is able to induce a swirling flow within the chamber when a hot air inlet is used instead of a fire. In this computational work, a configuration with nearly arbitrary geometries is modelled and the effect of the inlet temperature and velocity on the swirling strength is assessed. The computational results show reasonable agreement with the existing experimental data.

Optically addressed pressure sensors for transient gas dynamics: calibration of a preliminary design

Abstract: The design of pressure sensors based on interferometric measurements of diaphragm deflection for transient gas dynamics experiments is discussed. Quasi-steady calibration results from one such sensor are presented. Results from a dynamic calibration of the same sensor are also described. Predictions of diaphragm behaviour based on a clamped circular diaphragm model are within about 30% of the results obtained from the static and dynamic calibrations. However, a strong temperature sensitivity is also apparent. Future development will focus on reducing the temperature sensitivity of the sensor in transient applications.

Geometrical optimization of a swirling Savonius wind turbine using an open jet wind tunnel

Abstract: It has been suggested that waste heats or naturally available heat sources can be utilized to produce swirling flow by a design similar to that of split channels which is currently used to initiate fire whirls in laboratories. The new design combines the conventional Savonius wind turbine and split channel mechanisms. Previous computational and preliminary experimental works indicate a performance improvement in the new design (named as swirling Savonius turbine) compared to the conventional Savonius design. In this study, wind tunnel experiments have been carried out to optimize the swirling Savonius turbine geometry in terms of maximum power coefficient by considering several design parameters. The results indicate that the blade overlap ratio, hot air inlet diameter and the condition of the top end plate have significant influence on power and torque coefficients, while a larger aspect ratio and closed top end plate have some favourable effects on the performance. The optimum configuration has been tested in four different wind velocities to determine its influence on the performance, and power coefficients were found to be higher in high wind velocities. The performance comparison of optimum configuration with conventional Savonius rotor showed an increase of 24.12% in the coefficient of power.

Fiber Optic Bending Sensor for Water Level Monitoring: Development and Field Test: A Review

Abstract: In this paper, we describe a low cost optical sensor of water level based on fiber bending effect associated to the use of an elastomeric membrane. The sensor proposed has a particular design to be simple, reliable, and low cost. It is suitable to be used in tubes of embankment dams, tanks, and reservoirs. The sensor uses a standard single mode fiber and can measure the water levels up to 10 m or more, choosing the appropriate membrane. This paper describes the development of the sensor, a theoretical modeling, and the results of laboratory and field tests. Seven sensors were installed in an embankment dam where they have been used in a real time monitoring system based in optical time domain reflectometry.

Evolution of the Advancements in Cross Axis Wind Electric Machines

Abstract: This article presents a kind of apologetics for cross-flow wind machines At the beginning, general knowledge and initial stages of development for S-type rotors are described The historical review continues with the stage of reduced interest, followed by the stage of enhanced interest after the oil crisis of 70-ies The main advancements and advantages are conveyed Historical evolution of cross-flow runners is also addressed A brief look on the evolution of coaxial wind and electrical rotors is provided as an introduction to the authors’ approach for advancements: a combination of improvements of the conventional wind rotors and of their coupling to the electricity generators The invented Wind Electric Machine Without Stators is quoted The development of competitive vertical axis wind machines is suggested as an important public task, which has to change the agenda of the wind industry

Effects of flow parameters on the performance of vertical axis swirling type Savonius wind turbine

Abstract: Wind tunnel experiments were carried out on a geometrically optimal swirling Savonius turbine by varying flow parameters to determine their effects on power and torque coefficients. The optimum geometrical configuration used in this experiment was adopted from an earlier study that features 0.20 blade overlap ratio, 195˚ blade arc angle, and 1.06 rotor aspect ratio of a 320 mm diameter rotor with closed top end plate. The parameters considered in this experimental are the hot air temperature, hot air mass flow rate, hot air inlet diameter of swirl chamber, and the free-stream wind velocity. The results indicate that higher hot air temperature and hot air mass flow rate promotes performance of the turbine while power coefficient reached maximum at a certain hot air inlet diameter. Tests on the optimum geometry at four wind velocities revealed that power coefficients are higher in higher wind velocities.