2024-03-29T13:21:07+03:30
http://yujs.yu.ac.ir/jste/browse.php?mag_id=3&slc_lang=fa&sid=1
Journal of Selected Topics in Energy
jste
2588-4891
2588-4905
7
2017
2
1
Investigation of performance and exhaust emissions in direct injection engine using coconut oil biodiesel
Mahmood Reza
Rahimi
mrrahimi@yu.ac.ir
ŘJavad
Safaei
safaei.stpc@yahoo.com
Masoud
Nikbakht
m.nikbakht91@yahoo.com
In this paper, coal combustion process in a bubbling fluidized bed furnace were investigated experimentally. Analysis of experimental data shows that the coal size particles inlet to bed and rate of air injected into the furnace, are determinant parameter in bed temperature and proper combustion in the fluidized bed furnace. The highest temperature of 1050°C was obtained with air flow rate of 12 for the combustion of coal mixture with 75 wt% particles in group 2 and 25 wt% in group 3.
Bubbling Fluidized Bed
Combustion
Coal
Temperature distribution
2017
2
01
1
19
http://yujs.yu.ac.ir/jste/article-1-63-en.pdf
Journal of Selected Topics in Energy
jste
2588-4891
2588-4905
7
2017
2
1
The Effect of Metallic and Non-metalic Nano-coatings and Polarization of Incident Radiation on Radiation Properties of Nono-coatings
neda
khani esfand abad
neda.khani1987@yahoo.com
S.A.A
Oloomi
Amiroloomi@iauyazd.ac.ir
S.A.A
Mirjalili
The study aimed at investigating radiation properties of multi-layers constructions including underneath layer of silicon, slightly covered by non-metal coating of silicon nitrate and silicon dioxide, and metal coating of gold, silver and cooper in temperature of 25 degrees Celsius and polarized incident radiation. Ray Transfer Matrix model was used to calculate radiation properties of multi-layers constructions as well as experimental expressions of optical constants of slightly covered silicon. The transmission coefficient of metallic coatings in polarization types of P and S and non-polarized status was zero due to low penetration power and high radiation coefficient. In non-metallic coatings, on the other hand, the transmission coefficient increased contributing to the larger penetration depth of electromagnetic waves. The overall results indicated that polarization coefficient of transmission of type P was significantly larger than Type S in non-metallic coatings. Radiation coefficient of metallic coatings was significantly larger in comparison to non-metallic coatings. As the result, they can be used in industries requiring high radiation. The results indicated that in underneath silicon layers, in room temperature and wave length of.4 to.84 micrometer, the absorption and consequently radiation coefficients were insignificant. However, silver coating indicated significantly higher absorption and radiation. In addition, the fluctuation in polarization of the incident ray of P and S type resulted in an increase in emissivity and transmission factors. The findings showed that silver in comparison to gold and cooper revealed significantly higher radiation coefficient. In radiation angle of zero (normal), radiation properties were equal for both types of S and P.
Radiation properties
slightly covered silicon
polarization
coherent formulation
multi-layer construction
2017
2
01
20
24
http://yujs.yu.ac.ir/jste/article-1-36-en.pdf
Journal of Selected Topics in Energy
jste
2588-4891
2588-4905
7
2017
2
1
Combined Fuzzy-ACO Algorithm for Optimal Reconfiguration and Distributed Generation Allocation
hajar
bagheri tolabi
hajarbagheri1@gmail.com
m.r.
shakarami
book_authors@live.com
E.
Rok Rok
esmaeelrokrok1@gmail.com
This paper presents a new hybrid method for optimal multi-objective reconfiguration simultaneous determining the optimal size and location of Distributed Generation (DG) in a distribution feeder. The purposes of this research are reducing the losses, improving the voltage profile and equalizing the feeder load balancing in a distribution system. Ant Colony Optimization (ACO) approach as a Swarm Intelligence (SI) based algorithm is used to simultaneously reconfigure and identify the optimal capacity and location for installation of DG units in the distribution network. In order to facilitate the algorithm for multi-objective search ability, the optimization problem is formulated for minimizing fuzzy performance indices. The multi-objective optimization problem is transformed into a fuzzy inference system (FIS), where each objective function is quantified into a set of fuzzy objectives selected by fuzzy membership functions. The proposed method is validated using the IEEE 33 bus test system at nominal load. The obtained results prove this combined technique is more accurate and has an efficient convergence property compared to other intelligent search algorithms. Also, the obtained results lead to the conclusion that multi-objective reconfiguration along with placement of DGs can be more beneficial than separate single-objective optimization.
Fuzzy Inference System
Multi objective reconfiguration
Distributed Generation
Ant Colony Optimization
2017
2
01
34
41
http://yujs.yu.ac.ir/jste/article-1-41-en.pdf
Journal of Selected Topics in Energy
jste
2588-4891
2588-4905
7
2017
2
1
Investigation of the effects of boundary layer heating on the aerodynamics coefficients of transonic airfoil using the computational fluid dynamics
m.y.hashemi@azaruniv.ac.ir
h.rasooli160@gmail.com
This study aims at investigating aerodynamic coefficients changes by applying a two-dimensional heat flux on the wing in transonic regime. The numerical and experimental researches have shown that heat transfer on the fuselage has a significant impact on reducing drag (force). The current study aims also at investigating the effects of the heat transfer on aerodynamic coefficients of wing section. Accordingly, the turbulent transonic flow was numerically simulated around RAE2822 transonic airfoil with two different methods of modeling turbulent flow, namely, k–ε two-equation method and Reynolds stress five-equation model (RSM) and the obtained results were compared with experimental results. After choosing RSM as an appropriate method, subsequent investigations have been carried out with it. By applying heat flux in certain parts of upper and lower airfoil, the flow around it, is modeled and aerodynamic coefficients are extracted for airfoil and investigated. Studies showed that heating below the airfoil surface leads to change of aerodynamic coefficients with increasing the lift to drag ratio which can reduce fuel consumption and increase endurance of aircraft.
Computational fluid dynamics
Turbulent transonic flow
Boundary layer heating
Aerodynamics coefficients
2017
2
01
42
48
http://yujs.yu.ac.ir/jste/article-1-46-en.pdf
Journal of Selected Topics in Energy
jste
2588-4891
2588-4905
7
2017
2
1
Effect of an isothermal wall on the natural convection heat transfer from a horizontal cylinder
Pedram
Pournaderi
sp.pournaderi@yu.ac.ir
Sepehr
Rasekh
sepehrrasekh72@gmail.com
In this paper, effect of a horizontalisothermal wall on the natural convection heat transfer from a horizontal cylinder is numerically studied.For this purpose, effect of wall when it is located above the cylinder at various Rayleigh numbers and wall vertical positions are studiedand compared with the situation that wall is adiabatic. Fluent software is used to simulate the problem.Comparison of simulation results with available numerical results,confirms the accuracy of simulation. Simulation results show that in low wall distance from the cylinder,the isothermal wall causes an increase in meanNusselt number. By increasing this distance, mean Nusselt number decreases until reaching a minimum value. By more increase of this distance mean Nusselt number increases. Also, it is considered that in the case of isothermal wall Nusseltnumber is higher rather than adiabatic wall.
Natural convection
Horizontal cylinder
Isothermal wall
2017
2
01
49
55
http://yujs.yu.ac.ir/jste/article-1-51-en.pdf