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Showing 3 results for Kouravand
Alireza Najafi Amel, Shahriar Kouravand, Payam Zarafshan, Ali Mashaallah Kermani, Morteza Khashechi,
Volume 17, Issue 10 (1-2018)
Abstract
In this paper, optimization phase angle of alpha Stirling engine performed step by step method. After studying on the operation of various types of Stirling engines, the effect of the phase angle on the power and efficiency of Alpha Stirling engines was studied. The kinematic modeling of volumetric compression and expansion volumes has been done by ADAMS software. Then, the linearization of the thermodynamic equations was carried out on the basis of analysis of the isothermal and five-volume adiabatic stirling cycles to obtain the initial solution of its effective parameters on the power and efficiency. To optimize the phase angle between compression and expansion pistons, stepwise numerical solution of the stirling cycle was performed. Comparison of numerical solution with experimental data indicates an error rate of less than 5.3%. The simulation results show the optimum phase angle of 103 °. At this optimal angle, the results indicate an increase of 4.8% of the output power rather than the output power at a 90 ° pre-aligned angle. Simulation results indicate an improvement of 1.2% of the Alpha Stirling engine efficiency by adjusting this phase priority angle to the efficiency at 90 °.
H. Seifi Davary, Sh. Kouravand, I. Khatami,
Volume 20, Issue 1 (January 2020)
Abstract
The important factor in turbine efficiency is turbine rotation. The higher the rotor time at different speeds, especially at low speeds, increases the turbine power. In this regard, first, the airfoil NACA0015 was selected and the K-ω SST turbulence method was used for numerical analysis. The validation was performed using experimental results. The wind turbine was designed and fabricated by CATIA software. The aluminum sheet used by a series alloy is used to make smooth, porous leaves from simple cards and diamond-shaped leaves, in a porous form with 0.3 mm thick. The instrument used in measurement, testing and fabrication have been calibrated to compute more precisely and to generate wind flow from the four-fan blower. The results show that the darriues vertical axis wind turbine with porous and flat blades has begun to rotation at the speed of 2.3 and 3.9 m/s. At the speed of 2.5 and 3 m/s, the rotation of wind turbine porous blade doubled and at the speed of 4 m/s, its rotation speed was 3 times higher than the speed of straight blade turbine. The rotation of wind turbine porous blade in speeds of 4.5, 5, 5.5, 6, 6.5 and 7 m/s were 56.25 %, 20 %, 22 %, 15 %, 7.5 %, and 12% higher than the straight blade turbine and in speed of 8-10 m/s the rotation of the straight blade turbine and porous blade turbine is almost equal.
H. Seifi Davari , Sh. Kouravand , I. Khatami,
Volume 20, Issue 5 (May 2020)
Abstract
In this research, airfoil turbine blade airfoil Darriues vertical axis selected from three airfoils NACA0015, NACA0018 and NACA0021. The maximum ratio of the lift coefficients to the drag coefficient was determined in the Q-Blade software, and finally the airfoil NACA 0015 at speeds of 5 and 10M/s has the maximum value of the lift coefficient to the drag coefficient at an attack angle of 13 degrees equal to 2.58 and an attack angle of 6.5 degrees equal to 15.3. Then airfoil NACA 0015 was selected for numerical analysis and the turbulence method K-ω SST was used for numerical analysis and the results were verified using laboratory results. The wind turbine was designed and developed in CATIA software. Four wind fans were used to create wind power. The instruments used in measuring, testing and fabricating were calibrated. The results showed that the Self-Starting power of the porous blade in the speeds of 3, 4, 5, 7, 8m/s was %35, %33, %31, %37 and %48 less than the direct blade wind turbine, respectively.
