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propulsion-system
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Total 23 records
Ship acceleration motion under the action of a propulsion system: a combined empirical method for simulation and optimisation
, Article Journal of Marine Engineering and Technology ; 2020 ; Najafi, S ; Amini, E ; Dashtimansh, A ; Sharif University of Technology
Taylor and Francis Ltd
2020
Abstract
The current paper presents a simple mathematical model for replication of the transient acceleration motion of displacement hulls in calm water under the action of a propulsion system. Different empirical methods are coupled, and an operational speed problem is solved in the time domain. The resistance of the ship is calculated by using the Holtrop method. The values of thrust force, torque and propeller efficiency are computed by using B-Series empirical equations. The acceleration motion of the vessel, which is triggered as the engine starts to work, is simulated by solving a set of first-order differential equations, which are discretised in the time domain. It is shown that different...
Dynamic Simulation of the Propulsion System of a Flapping Wing Vehicle
, M.Sc. Thesis Sharif University of Technology ; Meghdari, Ali (Supervisor)
Abstract
Flapping wing vehicles produce aerodynamic forces through the flapping motion of their wings. A sample flapping wing mechanism is studied in this project, which propulsion system consists of a battery, a DC motor, a gearbox, a flapping mechanism and a flexible membrane wing. The purpose of this study is simulation of the whole propulsion system through identification and simulation of each sub-system. In the current research, after an introduction to the flapping wing vehicles, literature of the flapping vehicles is reviewed. By studying relevant articles, lack of a comprehensive simulation of all sub-systems is observed. So the goal of this research is obtaining an appropriate tool for...
Efficiency map of a switched reluctance motor using finite element method in vehicular applications
, Article 7th Internatonal Conference on Power Electronics, ICPE'07, Daegu, 22 October 2007 through 26 October 2007 ; 2007 , Pages 644-649 ; 9781424418725 (ISBN) ; Tara, E ; Sharif University of Technology
IEEE Computer Society
2007
Abstract
Switched Reluctance Motors (SRMs), which are simple and reliable motors, have attracted interest for electric vehicle propulsion systems. It is shown that an SRM offers a good performance at high acceleration and low speed driving conditions. Efficiency map of an electric motor is a very important characteristic specially when the motor is to be used in a wide range of speed and load variations, which is the case in electric propulsion systems. In this research, the efficiency map of an SRM is derived using a combination of the Finite Element Method (FEM) and a mathematical model. This efficiency map has been used for different driving cycles to test the SRM performance as a vehicle...
Design and Manufacture of Steam Jet Propulsion System
, M.Sc. Thesis Sharif University of Technology ; Seif, Mohammad Saeed (Supervisor)
Abstract
Nowadays, there is a focus on developing a propulsion system with higher efficiency and performance in comparison to conventional systems. Many diverse systems have been designed for the vessel propulsion and everyday, utilizing new ideas, their performance and energy consumption are being improved. Direct use of steam energy is a noble and new idea. In this research, the steam jet propulsion system has been explained and current worldwide research on the topic has been investigated. Considering the shortage of primary data in the field and the novelty of subject, required information for the manufacturing of a sample model of this special propulsion system has been gathered and a design for...
Numerical Modeling and Analyzing of Pumpjet Propulsion System
, M.Sc. Thesis Sharif University of Technology ; Seif, Mohammad Saeed (Supervisor)
Abstract
Nowadays, reaching higher speed in marine crafts and underwater vehicles mostly requires a modern propulsor with high efficiency and enhanced cavitation performance. Because of these requirements, numerous researches for developing the existing propulsion systems and invention of new systems have been conducted in recent years. One of the most sophisticated and developed propulsion systems that have high hydrodynamic efficiency and high cavitation performance and low acoustic signature is pumpjet. This propulsor contains a rotor, stator and a duct that surrounds two other parts. Stator reduces the swirl of flow coming from rotor and thereby reduces the loss of energy. High cavitation...
Minimization of time to reach final speed in planing craft by optimal control of drive and trim tab angles
, Article FAST 2013 - 12th International Conference on Fast Sea Transportation ; 2013 ; Seif, M. S ; Mehdigholi, H ; Sharif University of Technology
FAST 2013 Secretariat
2013
Abstract
Properly adjusting the trim angle during the craft speed up, plays an important role in easily passing through the resistance hump and to reach final speed in minimum possible time. Present study tries to reply to this question that how the angles applied to a trimmable drive system and trim tab of the planing craft should be changed during speed up from rest, to craft reach a final speed in minimum time. This is a time-optimal control problem with the drive and trim tab angles as its control variables. To solve this problem a 3-DOF dynamic model is developed here rely on empirical data and relations. For the propulsion system operation of propeller, drive and engine altogether are taken...
A comprehensive theoretical approach for analysing manoeuvring effects on ships by integrating hydrodynamics and power system
, Article IET Electrical Systems in Transportation ; Volume 12, Issue 2 , 2022 , Pages 89-101 ; 20429738 (ISSN) ; Peyghami, S ; Parniani, M ; Blaabjerg, F ; Sharif University of Technology
John Wiley and Sons Inc
2022
Abstract
Ship motions affect the propulsion system, which causes fluctuations in the power system. Mutually, the power system variations impact the ship velocity by generating speed changes in the propeller. Therefore, interconnecting the ship hydrodynamic and power system has paramount importance in designing and analysing an all-electric ship (AES). The lack of an integrated model that can be evaluated in various operating conditions, such as manoeuvring, is evident. This paper explores the required perceptions for the power system and hydrodynamic analysis of an AES. Then, an integrated theoretical model comprising both the ship motion and power system is proposed. In addition to providing an...
Optimal decision making for orbit transfer system of a student micro-satellite, using multi-criteria decision making
, Article 1st IEEE International Symposium on Systems Engineering, ISSE 2015 - Proceedings, 28 September 2015 through 30 September 2015 ; 2015 , Pages 29-33 ; 9781479919208 (ISBN) ; Mahrooz, M. H ; Rahmani, S ; IEEE Systems Council ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
One of the most important aspects of a successful space mission is the transition to the correct orbit and maintaining it. As a result, many modern orbit transfer techniques have been developed in space industry in order to accomplish this task in a more reliable and less expensive way. However, when it comes to the design of student satellites, usually there are serious limitations on the financial resources, technical database and satellite industry experts. These limitations may compromise the access to advanced methods and techniques. Therefore, reliability and expenses may no longer be the only criteria to be met in the process of design. As a result, at each step of the design, a...
Power management strategies based on propellers speed control in waves for mitigating power fluctuations of ships
, Article IEEE Transactions on Transportation Electrification ; Volume 8, Issue 3 , 2022 , Pages 3247-3260 ; 23327782 (ISSN) ; Peyghami, S ; Parniani, M ; Blaabjerg, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
This article proposes two novel power management strategies (PMSs) to enhance the electrical power quality in twin-screw all-electric ships (AESs) during vessel-wave encountering. Soothing PMS (SPMS) focuses on mitigating power fluctuations of the propulsion system since it has significant impacts on the power system in extreme conditions. For this purpose, the PMS modifies propellers' speed based on the in-and-out-of-water effect loss factor (LF) in wave collisions. This method does not require typical equipment, such as energy storage systems (ESSs), to moderate the variations. Hence, it decreases the ESS demand capacity and maintenance costs at the design and operation levels. An...
Developing a Method for the Dynamic Analysis of Flexible Flapping Wing
, M.Sc. Thesis Sharif University of Technology ; Meghdari, Ali (Supervisor)
Abstract
Flapping is one of the most usual solutions to produce aerodynamic lift and propulsive force in natural flights, in low Reynolds number. A sample flapping wing mechanism in which propulsion system consists of a battery, two very small DC electrical motors, two gearboxes, a flapping mechanism and flexible beams as wings is studied in this project.Different methods have been proposed to derive the governing equations of motion and simulate the flapping wing system. The main disadvantage of the previous proposed works is the lack of a comprehensive dynamical analysis of the complete system including its components.Therefore, the main objective of the present research is to propose an efficient...
The Effect of Performance of Ships Propeller on its Maneuvering in Shallow and Deep Water
, M.Sc. Thesis Sharif University of Technology ; Seif, Mohammad Saeed (Supervisor)
Abstract
In this thesis ship propeller performance in maneuvering conditions have been investigated which means an oblique flow condition for working propeller. Then results of these investigations have been put to use to simulate maneuvering using MMG equations. These calculations have been done to investigate nominal wake variations in different drift angles and depth conditions. In this project displacement vessel KVLCC2 and propeller POTSDAM VP1304 have been studied due to the abundance of experimental data. Calculations in this study have been carried in three steps: 1, calculation of nominal wake of the vessel in different drift angles and depths via CFD. 2, Using the results of previous...
Determination of Wake Effect of Stern on Performance of Marine Propeller with Self Propulsion Model Test
, M.Sc. Thesis Sharif University of Technology ; Seif, Mohammad Saeed (Supervisor)
Abstract
According to the increasing need of the world to increase the speed of existing technologies such as computers, cars, urban transport, etc. The need to carry goods at higher speeds is also a concern that due to its cost It can make a significant contribution to the economy. In the maritime industries, in addition to the commercial and economic orientation, there is also military capability the speed factor and the ability to navigate is very important for military vessels. The power in the sea is inevitably dependent to speed, so for Increasing the speed of vessels with regard to military and economic objectives needs optimized Propulsion systems which There are also limitations for them....
Numerical Simulation and Hydrodynamic Investigation of Oscillating Wing Inspired by Manta Ray
, Ph.D. Dissertation Sharif University of Technology ; Abbaspour Tehrani Fard, Majid (Supervisor) ; Darbandi, Masoud (Co-Supervisor)
Abstract
It has always been a human challenge to inspire natural configurations and phenomena and benefit from their merits in improving the performances of man-made proposed aero/hydro vehicles. For example, the manta rays are known for their great swimming performances. To design and fabricate an underwater robot based on the manta ray geometry and its kinematic characteristics, it is important to initially study its hydrodynamic behavior and possibly arrive at some key design parameters, which can remarkably help to figure out an optimum geometry with high swimming performances. The main objective of this study is to focus on the merits of gliding motion inspired by the manta ray fish considering...
Applying a hybrid DSMC/Navier-Stokes frame to explore the effect of splitter catalyst plates in micro/nanopropulsion systems
, Article Sensors and Actuators, A: Physical ; Volume 189 , January , 2013 , Pages 409-419 ; 09244247 (ISSN) ; Roohi, E ; Sharif University of Technology
2013
Abstract
In this study, we apply a hybrid direct simulation Monte Carlo (DSMC)/Navier-Stokes (NS) frame to simulate the effects of catalyst or splitter plates in propulsive efficiency of micro/nanopropulsion systems. Our hybrid frame uses the local Knudsen number based on the gradient of the flow properties (KnGLL) to distinct the continuum and molecular regions. This frame also uses the state-based coupling (Dirichlet-Dirichlet boundary-condition coupling) to transfer the information between the two regions. We simulate typical micro/nanopropulsion systems consisting of channels, catalyst or splitter plates, and convergent-divergent nozzles. According to the Kn GLL, we apply the NS solver to the...
Multi-body simulation of a flapping-wing robot using an efficient dynamical model
, Article Journal of the Brazilian Society of Mechanical Sciences and Engineering ; Volume 38, Issue 1 , 2016 , Pages 133-149 ; 16785878 (ISSN) ; Selk Ghafari, A ; Ebrahimi, A ; Meghdari, A ; Sharif University of Technology
Springer Verlag
Abstract
The aim of this article is to present an efficient dynamical model for simulating flapping robot performance employing the bond graph approach. For this purpose, the complete constitutive elements of the system under investigation, including the main body and accessories, flapping mechanism, flexible wings and propulsion system consisting of a battery, DC motors and gear boxes, are considered. A complete model of the system was developed appending bond graph models of the subsystems together utilizing appropriate junctions. The wings were also modeled using ANSYS only for an initial evaluation. Moreover, a computer model was developed employing the block-oriented structure of Simulink in...
Cogging force mitigation techniques in a modular linear permanent magnet motor
, Article IET Electric Power Applications ; Volume 10, Issue 7 , 2016 , Pages 667-674 ; 17518660 (ISSN) ; Nasiri Gheidari, Z ; Sharif University of Technology
Institution of Engineering and Technology
Abstract
Modular linear doubly salient permanent magnet motors are well adapted to linear propulsion systems because of their distinct characteristics, such as high efficiency and power density, reduced maintenance and initial cost, low noise and permanent magnet (PM) leakage flux, and fault tolerance capability. However, such motors suffer from high cogging thrust. In this study, various techniques based on previously proposed methods for PM machines are applied on the studied motor and evaluated by using non-linear three-dimensional time-stepping finite element analysis; three novel, optimised techniques are then presented. The techniques presented are based on the minimisation of the variation in...
Modeling in-and-out-of-water impact on all-electric ship power system considering propeller submergence in waves
, Article 2021 IEEE Transportation Electrification Conference and Expo, ITEC 2021, 21 June 2021 through 25 June 2021 ; 2021 , Pages 533-538 ; 9781728175836 (ISBN) ; Peyghami, S ; Parniani, M ; Blaabjerg, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
Despite the advantages of employing an electric propulsion system in All-Electric Ships (AES), additional power fluctuation sources have emerged in the ship power system as a result. Since the propellers are the primary power consumers in the AES, these fluctuations may significantly affect its power system power quality. Thus, for optimal performance of the ship power system, these fluctuations need to be rigorously investigated at the design level of vessels. Waves collision is one of the critical conditions where propellers inject power fluctuations into the ship power system. Therefore, a comprehensive model is essential to analyze the propellers in-and-out-of-water effect on the ship...
Multi-objective trade-off analysis of an integrated cold gas propulsion system
, Article Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering ; Volume 227, Issue 8 , 2013 , Pages 1233-1250 ; 09544100 (ISSN) ; Gol, H. A ; Sharif University of Technology
2013
Abstract
The overall design of cold gas propulsion systems is pretty complicated when considering the mission requirements, operating constraints and functional limitations imposed by the mechanical components. To address this complication, a precise design process is proposed, which attempts to optimize the cost of operation as well as to minimize the waste volume and weight by using multi-objective trade-off analysis. This analysis is based on a set of ordinary differential equations that are solved iteratively to describe the optimal behavior of the system. Therefore, a numerical code is being developed to give insight on the design sensitivity with respect to uncertainties on the design...
Performance study of an inlet in supersonic flow
, Article Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering ; Volume 227, Issue 1 , 2013 , Pages 159-174 ; 09544100 (ISSN) ; Farahani, M ; Sharif University of Technology
2013
Abstract
The performance characteristics of an axisymmetric inlet at its design and off-design operational conditions are experimentally investigated. The model is tested for wide ranges of free stream Mach numbers, M∞ = 1.5-2.5, and mass flow rates. For each test, the pressure recovery, the mass flow passing through the inlet and the pressure distribution over the spike and the cowl are measured. In addition, the shock wave formed in front of the inlet is visualized. The characteristic curve of the inlet is then obtained for each free stream Mach number. As the Mach number is increased, the pressure recovery is reduced, but the maximum value of the mass flow rate grows up. Variations of the mass...
Optimal apogee burn time for low thrust spinning satellite in low altitude
, Article European Journal of Operational Research ; Volume 222, Issue 2 , 2012 , Pages 386-391 ; 03772217 (ISSN) ; Assadian, N ; Sharif University of Technology
2012
Abstract
In this study, the optimal burn time for low-thrust impulsive propulsion systems is investigated to raise the perigee altitude of a low-Earth orbit. The maneuver is done using spin-stabilized attitude control and impulsive thrusting system for a time interval centered about apogee point. On the one hand, the low value of the thrust level causes more burn time needed to accomplish the transfer. This, in turn, will cause more thrust loss due to the deviation between the thrust axis (spin axis) and the velocity vector of the satellite. On the other hand, for small thrust duration, the transfer needs more revolutions around the Earth and more travel in lower altitudes with dense atmosphere and...