Bobol University of Technology

Iran

Bobol University of Technology

Iran
SEARCH FILTERS
Time filter
Source Type

Ghadi A.Z.,Islamic Azad University | Goodarzian H.,Islamic Azad University | Gorji-Bandpy M.,Bobol University of Technology | Valipour M.S.,Semnan University
Engineering Applications of Computational Fluid Mechanics | Year: 2012

In this study, convection heat transfer around a solid circular cylinder embedded in porous media in the presence of magnetic field has been numerically investigated. Governing equations containing mass continuity, momentum and energy equations have been extended in polar coordinate system for porous media. The equations have been discretized by using a finite volume method (FVM). The variables have been defined in a staggered grid and a pressure correction-based iterative algorithm SIMPLE has been applied for solving the pressure linked equations. The range of Reynolds and Peclet numbers are between 1 and 40. Also Darcy number (Da) differs within the range of 7 10 and 2 10 and Magnetic parameter (M) varies between 1 and 10. The impact of Darcy number and magnetic parameter on the local and mean Nu number has been studied. It has been observed that the maximum amount of local Nu number increases with increasing Re number. It has been also deduced that the mean Nu number decreases with any increase in Darcy number.


Seyyedbarzegar S.M.,Bobol University of Technology | Mirzaie M.,Bobol University of Technology
IET Generation, Transmission and Distribution | Year: 2016

This study proposes a new method for modelling of metal-oxide surge arresters (MOSAs) thermal balance diagram based on power loss and heat dispersion curve. Adaptive network-based fuzzy inference system (ANFIS)-based method was offered to compute surge arrester power loss characteristic. Thermal stability (TS) of surge arrester, which is analysed by thermal balance diagram, has a great influence on their proper functions. MOSA material variation is an important factor that has an influence on its TS. Degradation factor (DF) was introduced as a new index in this study to represent material variations of MOSA. Therefore, applied voltage, temperature and DF were considered as inputs in ANFIS model to obtain accurate power loss which is a very important factor in TS characteristic. Heat dispersion curve was obtained as a main feature in the thermal balance diagram from surge arrester cooling curve. Degrading effect was considered using voltage and current measured from MOSA which are degraded by utilisation in the network. In addition, effect of assembling process has been considered by using new different varistors in experimental measurements. This study shows that the thermal balance diagram of surge arrester is predictable with a good accuracy by using artificial model. © The Institution of Engineering and Technology.


Khodsuz M.,Bobol University of Technology | Mirzaie M.,Bobol University of Technology
IET Science, Measurement and Technology | Year: 2015

Metal-oxide surge arresters are one of the most important equipments for power system protection against switching and lightning over-voltages. Surge arresters leakage currents increase by the operating time. In this study, the important factors on leakage current variations such as surface contamination, ultraviolet ageing and varistor degradation have been studied. To accomplish this purpose, experimental tests have been performed on various polymer housed surge arresters. Fast Fourier transform analysis has been performed on measured leakage currents. Results show that ultraviolet radiation and varistor degradation affect resistive harmonic components, especially the third and fifth harmonics. Moreover, it is observed that surface contamination has influence on fundamental harmonic variation more than ultraviolet ageing. In addition, combination of ultraviolet radiation and pollution had more effect on leakage currents. The investigation and the discussion of the results can be used to easily analyse arresters condition leading to effective schedule maintenance. © 2015. The Institution of Engineering and Technology.


Meysam Seyyedbarzegrar S.,Bobol University of Technology | Mirzaie M.,Bobol University of Technology
Journal of Intelligent and Fuzzy Systems | Year: 2015

This paper proposes a new method to estimate power loss characteristics of metal oxide surge arresters. The method was used to compute surge arrester power loss curve based on adaptive network based fuzzy inference system (ANFIS) and artificial neural network (ANN). Surge arrester operating history is an important factor that bears influence on its power loss. Degradation was, in this paper, introduced as a new index to represent operating history of metal oxide surge arrester. Therefore, applied voltage, temperature and degradation factor were considered as inputs in ANFIS system and ANN models to obtain accurate power loss which is a very important factor in surge arrester thermal stability. Degrading effect was undertaken by measurement voltage and current in varistors degraded by utilization in network. The results of the two artificial models were compared. Results show that ANFIS was more accurate than ANN. This study shows that the power loss characteristics of surge arrester are to a great extent accurately predictable using proposed artificial model. © 2015 - IOS Press and the authors. All rights reserved.


Gorji-Bandpy M.,Bobol University of Technology | Goodarzian H.,Islamic Azad University
Thermal Science | Year: 2011

Exergoeconomic analysis helps designers to find ways to improve the performance of a system in a cost effective way. This can play a vital role in the analysis, design, and optimization of thermal systems. Thermoeconomic optimization is a powerful and effective tool in finding the best solutions between the two competing objectives, minimizing economic costs and maximizing exergetic efficiency. In thispa-per, operating parameters of a gas turbine power plant that produce 140 MW of electricity were optimized using exergoeconomic principles and genetic algot rithms. The analysis shows that the cost of final product is 9.78% lower with respect to the base case. This is achieved with 8.77% increase in total capital investment. Also thermoeconomic analysis and evaluation were performed for the gas turbine power plant. The results show the deep relation of the unit cost on the change of the operating parameters.

Loading Bobol University of Technology collaborators
Loading Bobol University of Technology collaborators