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steady-state-performance
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Experimental Investigation of the Effect of Nano-Fluid on the Performance of Pulsating Heat Pipe
, M.Sc. Thesis Sharif University of Technology ; Saeedi, Mohammad Hassan (Supervisor) ; Kazemzadeh Hannani, Siamak (Supervisor) ; Shafii, Behshad (Supervisor)
Abstract
Improving efficiency of heat exchangers has always been an important concern for the industry. Pulsating Heat Pipes (PHPs) are novel and efficient technology in the field of heat transfer. PHPs are widely used in solar water heaters, solar desalination systems, etc. In this research, thermal performance of Open Loop Pulsating Heat Pipes (OLPHPs) using three different ferrofluids (ferrofluid without surfactant and nanoparticles’ coating, ferrofluid with coating of nanoparticles, and ferrofluid with surfactant) is experimentally investigated. In addition, effects of charging ratio (20, 40, 60, and 80%), heating power (20, 30, 40, 50, 60, 70, 80, 100, 120, 140, 160, 180, 200, 240, 280, 320,...
Experimental Investigation of Pulsating Heat Pipe Filled with Nanofluid and Microfluid and Influencing Factors
, M.Sc. Thesis Sharif University of Technology ; Saidi, Mohammad Hassan (Supervisor) ; Behshad Shafii, Mohammad (Co-Advisor) ; Afshin, Hossein (Co-Advisor)
Abstract
Improving efficiency of heat exchangers has always been an important concern for the industry. Pulsating heat pipes are novel and efficient technology in the field of heat transfer. Pulsating heat pipes are widely used in solar water heaters, solar desalination systems, air conditioning systems, cooling of electronical boards, etc. these applications explain the necessity of performing this study in our country. In this research, thermal performance of open loop pulsating heat pipes using two operating fluids (ferrofluid with surfactant and aluminum microfluid) is experimentally investigated. Start-up and steady thermal performance of pulsating heat pipes charged with these two operating...
Ferrofluidic open loop pulsating heat pipes: Efficient candidates for thermal management of electronics
, Article Experimental Heat Transfer ; Vol. 27, issue. 3 , Dec , 2014 , p. 296-312 ; ISSN: 08916152 ; Taslimifar, M ; Saidi, M. H ; Shafii, M. B ; Afshin, H ; Hannani, S. K ; Sharif University of Technology
Abstract
Thermal management of electronic devices is presently a serious concern. This article investigates the thermal performance of a five-turn open-loop pulsating heat pipe in both start-up and steady thermal conditions. The effects of working fluid, namely water and ferrofluid, heat input, charging ratio, ferrofluid concentration, orientation, as well as application of magnetic field, are explored. Experimental results show that using ferrofluid enhances the thermal performance in comparison with the case of distilled water under certain conditions. In addition, applying a magnetic field on the open-loop pulsating heat pipe charged with ferrofluid improves its thermal performance. Charging...
A novel approach for the steady-state analysis of a three-phase self excited induction generator including series compensation
, Article ISIEA 2010 - 2010 IEEE Symposium on Industrial Electronics and Applications, 3 October 2010 through 5 October 2010, Penang ; 2010 , Pages 371-375 ; 9781424476473 (ISBN) ; Kashiha, A ; Ansari, K ; Sharif University of Technology
2010
Abstract
A new method to evaluate the steady state performance of a three-phase self excited induction generator based on conductance minimization is proposed. It can be simply used to take series compensation into account. Among the priorities of this method are the absence of convergence problem and flexibility. Simple methods to find the frequency and magnetizing reactance have been proposed. Simulation results show the efficiency of this method
Control of high order integrator chain systems subjected to disturbance and saturated control: A new adaptive scheme
, Article Automatica ; Volume 100 , 2019 , Pages 108-113 ; 00051098 (ISSN) ; Ahi, B ; Haeri, M ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
This paper is concerned with the global stabilization of multiple integrator systems subjected to input saturation. Among the existing works, nested saturation method has been demonstrated to be an effective tool. In the present contribution, an adaptive nested saturation feedback law is proposed which takes the advantages of time varying parameters in the saturation functions along with employing the well-known extended state observer. The global stability of the proposed approach for a desired order of integrators’ chain is demonstrated. The performance of the proposed control law is compared with the existing methods in the case of a triple integrator chain. It is shown that the proposed...
Global hybrid modeling and control of a buck converter: a novel concept
, Article International Journal of Circuit Theory and Applications ; Volume 37, Issue 9 , 2009 , Pages 968-986 ; 00989886 (ISSN) ; Mokhtari, H ; Sharif University of Technology
2009
Abstract
Several attempts have been made to design suitable controllers for DC-DC converters. However, these designs suffer from model inaccuracy or their inability to desirably function in both continuous and discontinuous current modes. This paper presents a novel switching scheme based on hybrid modeling to control a buck converter using mixed logical dynamical (MLD) methodologies. The proposed method is capable of globally controlling the converter in both continuous and discontinuous current modes of operation by considering all constraints in the physical plant such as maximum inductor current and capacitor voltage limits. Different loads and input voltage disturbances are simulated in MATLAB...