Sharif Digital Repository

In the present study, for cost-effective brine elimination of desalination plants, a hybrid system consisting of a multiple-effect distillation unit and a humidification-dehumidification unit is proposed. The development process of the hybrid system was carried out in two main steps: 1) evaluation of electricity-driven and heat-driven humidification-dehumidification brine concentrators 2) redesigning the humidification-dehumidification unit according to the results of step one and hybridization the unit with a multiple-effect distillation system. All the steps are assessed using the energy, exergy, exergoeconomics, and exergoenvironmental tools.Among the three heat-driven and... 

In electronic health, data is stored and retrieved electronically at the local or national level for clinical, educational and administrative purposes. The importance of data from citizens, patients, professionals and providers of healthcare and policy-makers points of view make it a valuable asset. In recent years, we confront the emergence of the Internet of Things and its widespread use in electronic health. In this area, health sensors such as a heart rate sensor, a blood glucose sensor, or a respiratory sensor provide information about each person that can be sent through the network to the physician. Such a continuous remote monitoring allows physicians to take better care of patients... 

Compressors are one of the most important components of gas turbines and turbomachinery processes. Thus some precise and quick tools are needed for design and analysis purposes. Despite of vast development of Computational Fluid Dynamics (CFD) tools, Through-Flow Streamline Curvature Methods (SCM) has retained their position. 2D and quasi-3D forms of SCM in combination with CFD results nowadays make more than 80% of turbomachinery design process of axial and radial compressors and turbines. In this thesis, the basics of developing a tool for axial-flow compressor analysis are introduced. As will be seen, this analysis tool can be used for design purposes too. The method that is chosen for... 

Axial compression systems are widely used in many aerodynamic applications. However, the operability of such systems is limited at low mass flow rates by fluid dynamic instabilities. These instabilities lead the compressor to rotating stall or surge. In some instances, a combination of rotating stall and surge, called modified surge, has also been observed. In this research Moore – Greitzer model that the principle of constant speed mode checks as a base case has been considered and the developed condition of this model in which the dynamic model of the shaft will also respect and shaft rotational speed as a basis for state shall consider, has been analyzed.
In this study the effect of... 

Biotechnology is one of the fields that has had great advances in the past decades, and therefore controlling biological processes (bioreactors) is considered as an important issue. The purpose of current thesis is designing an adaptive controller for a bioreactor by considering input constrain and proving the stability of closed loop. A standard bioreactor has been chosen for this purpose. First a non-adaptive controller has been designed. Then an adaptive controller is designed and implemented on a bioreactor in the presence of input constraint, because in practice the system parameters are unknown. Finally by applying disturbance to the system, it has been shown that the proposed control... 

Various factors, such as increasing or decreasing the heat removal from the initial circuit, or increasing the flow rate of the cooling fluid in the reactor, causes the phenomenon of the coolant mixing in the PWR reactors. In this project, the thermohydraulic test of coolant mixing has been simulated in the pressure vessel of the Bushehr nuclear reactor. In this test, the mixing of the coolant caused by the reduction of heat removal from the primary circuit by the secondary circuit is investigated. In this case, the primary circuit temperature increases in the loop where the heat removal is reduced. The most important consequence of this event is the reactivity changes at the core of the... 

In order to ensure the safety of the plants, a set of commissioning tests based on international standards for nuclear power plants is carried out before operation. In this research, one of the Bushehr power plant commissioning tests, the loop connection primary circuit cooling pump test, was simulated using the RELAP5 code. In this test, the effects of loop connection primary circuit pumps on the thermohydraulic parameters and the eneterance of test-related systems was evaluated. After simulating the systems related to the test and extracting the results of the stable state, were evaluated the transient results was obtained with the experimental results of the test of loop connection the... 

LOOP accident is one of the most important accidents in NPPS and it leads to loss of power supply of the RCP pumps which are the main pumps of primary circuit. Subsequently trip of the rector occurs. In safety analysis, concerning worst conditions, assumes that after a small period of time, main generator of plant stops working and loss of AC power supply of all power plant loads including safety systems ocures. To control of this accident, it’s necessary to startup and load backup power supply system (EDGs) for at least one safety channels, if not, the accident moves forwards and becomes S.B.O accident which is more important accident that ends to core damage because of stops working of all... 

Identification of different hazards in a UF6 production process, and evaluation of the risk originated from these hazards is the main objective of this project. A number of hazards are present in a typical UF6 production process, such as leakage of chemical gases like HF and F2 and also radioactive UF6 gas release. In order to evaluate risk due to these hazards, probabilistic approach has been used. Due to lack of probabilistic safety criteria (PSC) for chemical releases, only for UF6 gas release risk assessment has been done. As a first step in PSA of this process eight groups of initiating events have been identified using HAZOP study, and for each initiating event, event tree analysis... 

Efforts to model and control surge, as the underlying instability of centrifugal compressors, were conducted. Of the three major instabilities in compressors, namely chokage, stall and surge, the latter has a significant role in limiting the available range of operation in centrifugal compressors, which are the most common devices for the transportation of Natural gas. The customary method to circumvent surge, which if occurred, could impose severe, catastrophic and irreversible damages to the machine, is to avoid the zones in which it is likely to develop by means of a recycling system. These often called "surge avoidance" or "surge prevention" schemes have the benefit of high reliability,... 

In this study, the thermal-hydraulic analysis of prismatic HTGR’s core with natural convection has been studied using porous media approach. VHTR are the new generation reactors which due to special neutron and thermo physical properties have highly inherent safety. In lose of forced circulation accident, decay heat is transferred from core to pressure vessel wall and then to water tubes in concrete wall at reactor cavity with conduction, convection and radiation automatically. In this case the high volume of decay heat is stored in graphite block with high thermal capacity and is prevented the instantaneous temperature rising.
The aim of this study is justifying inherent safety of HTGR... 

This research study presents an experimental investigation on forced convection heat transfer of an aqueous ferrofluid flow passing through a circular copper tube in the presence of an alternating magnetic field. The flow passes through the tube under a uniform heat flux and laminar flow conditions. The primary objective was to intensify the particle migration and disturbance of the boundary layer by utilizing the magnetic field effect on the nanoparticles for more heat transfer enhancement. Complicated convection regimes caused by interactions between magnetic nanoparticles under various conditions were studied. The process of heat transfer was examined with different volume concentrations... 

One of the topics that has been given great consideration after restructuring and smart grid emergence, is loss management. This subject is specifically important in distribution systems, which have been reported to have 70% of the total loss in power systems. In this thesis, distribution loss is studied and its affecting factors are analyzed. Then loss optimization and loss cost allocation to distribution consumers are studeid. In order to acheive these two goals, it is neccessary for the distribution system to have the capabilities of a smart grid. The subjectof distribution reconfiguration is duiscussed as one of the loss reduction methods. Traditional reconfiguration problem trend... 

Inadvertent opening safety valve of pressurizer (SVP) is one of the most common initiator events in Booshehr nuclear reactors with occurrence frequency of 1.1E-0.2. This event has the third rank in initiator event among 16 other events (Loop and Compensated LOCA were ranked as first and second respectively). So special attention must be paid to SVP and the operators need to have specific trainings on this matter. In this thesis, the SVP as initiator event is being considered and the sequence which lead to core damage (CD), according to design informations is being modeled moreover the qualitative and quantitative analysis is carried out. In the modeling process we have used the SAPHIRE... 

Following Three Mile Island (TMI) accident in 1979, first severe accident (SA) in Nuclear Power Plants (NPPs), Accident Management Support Tools (AMSTs) were developed and installed in a number of NPPs. Lessons learned from Fukushima accident highlighted importance of Accident Management (AM) in mitigation severe radiological consequences after a SA and suggested reconsiderations of AM program which in turn created the need for AMSTs adaption and modernization. An efficient AMSTs should have the following principal capabilities: (1) Identification of accidents and diagnosis of the plant damage state (PDS), (2) Prediction of accident progress path and (3) Source term analysis and prediction... 

Due to nuclear power plants’ growing roll in providing energy, analyzing probable accidents and their prevention is of vital importance. The thermal-hydraulic shock accident which happened in Bushehr nuclear power plant deaerator has been simulated in this study. Steam bubble collapsing which takes place in two phase medium by mixing steam and subcooled water leads to this kind of shock causing financial and physical irreparable damage in nuclear power plants. For carrying out this simulation, first an steady state model of the deaerator was run using RELAP5 code and then using this model and other plant’s data such as the ropert of the accident and plant’s Final Safety Analysis Report... 

Loose parts in the primary circuit of a nuclear power plant, causing damage to the fuel rods and other equipment, so early localization and mass estimation of this pieces can provide context of safety measures for the reactor after an event.Acoustic signals emitted by the location of these parts provide enough information to estimate their location and mass. So with obtain time-of-arrival differences between sensors and sound velocity can be estimate loose part location. In this thesis signals of the sensors in Bushehr power plant monitoring system are analyzied. To estimate the loose part locations, the time delays between sensors must be calculated. The time difference between the sensors...