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RISS 인기검색어
- 검색키워드
- 저자 : Peyman Zahedi (검색결과 4 건)
- 무료
- 기관 내 무료
- 유료
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Peyman Zahedi,Kianoosh Yousefi 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.1
We studied the effects of increasing pressure and adding carbon dioxide, hydrogen and nitrogen to Methane-air mixture on premixedlaminar burning velocity and NO formation in experimentally and numerically methods. Equivalence ratio was considered within 0.7 to1.3 for initial pressure between 0.1 to 0.5 MPa and initial temperature was separately considered 298 K. Mole fractions of carbon dioxide,hydrogen and nitrogen were regarded in mixture from 0 to 0.2. Heat flux method was used for measurement of burning velocities ofMethane-air mixtures diluted with CO2 and N2. Experimental results were compared to the calculations using a detailed chemical kineticscheme (GRI-MECH 3.0). The results in atmosphere pressure for Methane-air mixture were calculated and compared with the results ofliterature. Results were in good agreement with published data in the literature. Then, by adding carbon dioxide and nitrogen to Methaneairmixture, we witnessed that laminar burning velocity was decreased, whereas by increasing hydrogen, the laminar burning velocitywas increased. Finally, the results showed that by increasing the pressure, the premixed laminar burning velocity decreased for all mixtures,and NO formation indicates considerable increase, whereas the laminar flame thickness decreases.
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Peyman Zahedi,Reza Saleh,Roberto Moreno-Atanasio,Kianoosh Yousefi 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.8
Numerical simulations have been carried out to investigate the formation and motion of single bubble inliquids using volume-of-fluid (VOF) method using the software platform of FLUENT 6.3. Transient conservation massand momentum equations with considering the effects of surface tension and gravitational force were solved by thepressure implicit splitting operator (PISO) algorithm to simulate the behavior of gas–liquid interface movements inthe VOF method. The simulation results of bubble formation and characteristics were in reasonable agreement withexperimental observations and available literature results. Effects of fluid physical properties, operation conditions suchas orifice diameter on bubble behavior, detachment time, bubble formation frequency and bubble diameter were numericallystudied. The simulations showed that bubble size and bubble detachment times are linear functions of surfacetension and decrease exponentially with the increase in liquid density. In contrast, only a small influence of the fluidviscosity on bubble size and detachment time was observed. Bubble collapse at a free surface simulation with VOFmethod was also investigated.
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Study of the Effect of Geometric Parameters of Steel Block Slit Dampers on Energy Absorption
Peyman Katal Mohseni,Amin Zahedi-khameneh,Omid Naeemifar 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.3
In this study, a new type of steel block slit dampers (BSD) has been investigated. This type of damper not only provides good seismic performance but can be easily repaired and replaced after a strong earthquake. The stability of these dampers under periodic loading and the hysteresis behavior was also investigated in this study. It should be noted that energy dissipations and plastic deformation are concentrated only in steel slit dampers (SSDs) and plastic behavior of the beam and column, and they are both more energy-absorbing and more economical than SSDs. Therefore, in this study, eff ort has been made to optimize and increase the energy absorption of these dampers. Therefore, in this study, eight samples with diff erent geometric dimensions have been simulated to develop and increase energy absorption of the steel BSD, and the results indicate that the slit dampers have more ductility and stiff ness than those of previous studies, which considerably increased the energy absorption in hysteresis cycles in all specimens.
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Numerical study of blowing and suction slot geometry optimization on NACA 0012 airfoil
Kianoosh Yousefi,Reza Saleh,Peyman Zahedi 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.4
The effects of jet width on blowing and suction flow control were evaluated for a NACA 0012 airfoil. RANS equations were employedin conjunction with a Menter’s shear stress turbulent model. Tangential and perpendicular blowing at the trailing edge and perpendicularsuction at the leading edge were applied on the airfoil upper surface. The jet widths were varied from 1.5% to 4% of the chordlength, and the jet velocity was 0.3 and 0.5 of the free-stream velocity. Results of this study demonstrated that when the blowing jet widthincreases, the lift-to-drag ratio rises continuously in tangential blowing and decreases quasi-linearly in perpendicular blowing. The jetwidths of 3.5% and 4% of the chord length are the most effective amounts for tangential blowing, and smaller jet widths are more effectivefor perpendicular blowing. The lift-to-drag ratio improves when the suction jet width increases and reaches its maximum value at2.5% of the chord length.
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