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Numerical-Analytical Modeling And Fabrication of A New Vehicle Cooling System Using Vapor-Jet Refrigeration Cycle
,
M.Sc. Thesis
Sharif University of Technology
;
Farhanieh, Bijan
(Supervisor)
Abstract
Today, the world energy crisis, the need to optimize its consumption and discussion to reduce fuel consumption has become a vital issue. The conventional vehicle air conditioning system due to compressor in refrigeration cycle, which has causes a severe loss in engine useful power, increasing fuel consumption, etc. Therefore, the main goal of this project is the feasibility of the vehicle cooler replacement with the vapor jet refrigeration cycle. In this cycle, the energy required for completing the refrigeration cycle is provided from the heat of the water inside the radiator that is possible with conventional refrigeration cycle. The first stage of this project includes design and...
Experimental Study of Hydraulic Characteristics of Perforated Pipes in Submerged Area
, M.Sc. Thesis Sharif University of Technology ; Jamali, Mir Mosaddegh (Supervisor)
Abstract
In small settling tanks, the sludges can be removed using perforated pipes. In this method the pipe is placed in the depth of a fluid and the lateral inflow through perforations lead to the outlet. Since there are few researches about hydraulic characteristic of perforated pipes, this research will investigate the hyadraulic characteristic of these pipes experimentally. One of the main objectives of these pipes is to use the entire lenghte of the pipe and also provide the uniform distribution of inflow. In the past studies, it was found out that inflow mostly comes through downstream perforations. The objective of this research is to find the distribution of discharge along the perporated...
Experimental and numerical simulation of the effect of particles on flow structures in secondary sedimentation tanks
, Article Journal of Applied Fluid Mechanics ; Volume 5, Issue 2 , 2012 , Pages 15-23 ; 17353572 (ISSN) ; Firoozabadi, B ; Afshin, H ; Sharif University of Technology
JAFM
2012
Abstract
Sedimentation tanks are designed for removal of floating solids in water flowing through the water treatment plants. These tanks are one of the most important parts of water treatment plants and their performance directly affects the functionality of these systems. Flow pattern has an important role in the design and performance improvement of sedimentation tanks. In this work, an experimental study of particle-laden flow in a rectangular sedimentation tank has been performed. Kaolin was used as solid particles in these experiments. Also, a numerical simulation was developed using the finite volume method with a k-e turbulent model. The results of the numerical model agree well with the...
Theoretical and experimental investigation of density jump on an inclined surface
, Article Scientia Iranica ; Vol. 21, Issue. 5 , 2014 , pp. 1655-1665 ; ISSN :1026-3098 ; Sarnie, M ; Firoozabadi, B ; Afshin, H ; Sharif University of Technology
Abstract
The density jump on an inclined surface is analyzed using an integral method by applying mass and momentum conservation equations. The jump occurs in a two-layered fluid flow in which the upper layer is stagnant and very deep. A relation is derived, which gives the conjugate depth ratio as a function of inlet densimetric Froude number, inlet concentration ratio, bed slope and entrainment. A set of experiments are performed to verify the relation. The theory and the measurements are in good agreement. The analysis reveals that increasing the surface inclination results in a decrease in the conjugate depth ratio. This analysis also shows that the densimetric Froude number just after the jump...
Experimental Investigation of Pulsating Heat Pipe
, M.Sc. Thesis Sharif University of Technology ; Shafiee, Mohammad Behshad (Supervisor)
Abstract
Pulsating heat pipes (PHP) are complex heat transfer devices which unlike conventional heat pipes do not contain any wick in their structure. The effective parameters consist of; working fluid, volumetric filling ratio, operational orientation and input heat power have been investigated here. The experimental set-up we have contemplated, fabricated and tested included five turns, made of copper tube coupled with two glass tube of internal diameter 1.8 mm. The height of evaporator, condenser and adiabatic section was 60, 60 and 150 mm, respectively. The evaporator was heated with electrical element connected to an AC variant power supply and the condenser was connected to a constant...
Modeling and Control of a Carangiform Fish Robot with Experimental Validation of the Forces Obtained by Large Amplitude Elongated Body Theory of Lighthill
, M.Sc. Thesis Sharif University of Technology ; Vossoughi, Gholamreza (Supervisor)
Abstract
Modeling and Control are fundamental issues for fish robots, which can play basic roles in design, optimization, fabrication, and eventually utilization of them. A review on the literature reveals the shortage of an analytical closed form model with little simplifications and high precision, and also control works based on such models. Studying LAEBT theory, it is shown that this theory is suitable for determining the forces produced due to the tail movements considered in the present work, and then it is used to determine the forces. Experimental investigations by means of the setup made for this purpose showed that the obtained equations for the forces have got acceptable precision....
An Experimental Study of the Effects of Sweep Wing on the Boundary Layer of 2D Wing
, M.Sc. Thesis Sharif University of Technology ; Soltani, Mohammad Reza (Supervisor) ; Davari, Ali Reza (Co-Advisor)
Abstract
The behavior of boundary layer under the effect of the sweep angle is considered. The measurements were performed by a pitot tube rake. Three models with various sweep angels at angles of attack -2, 0 and 2 degree were tested. Both tip and root of all wings were closed by flat plates in order to prevent the flow to roll-up. However the flow field on the wing was still three-dimensional because of the sweep angle. The velocity on the wing has two components; longitudinal and lateral. The cross flow emerges due to the non-equilibrium of pressure and centrifugal forces. The velocity profiles showed that the magnitude of cross flow was stronger near the leading edge of the wing. The cross flow...
Experimental Investigation of wake flow of a Supercritical Airfoil in Transonic Regime
, M.Sc. Thesis Sharif University of Technology ; Soltani, Mohammad Reza (Supervisor)
Abstract
Transonic flow study is important due to its vast applications. Supercritical airfoils are designed for transonic flow to postpone drag divergence and reduce the strength of shock. This type of airfoils are chiefly used in modern commercial airplanes because of their low drag in transonic regime and, as a result, reduction in their fuel consumption. Using supercritical airfoils needs accurate investigation of flow field due to several influential factors such as specific geometry, nonlinear nature of flow phenomena, and compressibility effects. However, the availability of experimental and numerical data for supercritical airfoils is less than that of the conventional ones. Thus,...
Experimental Investigation of Optimum Acid Injection Rate for Matrix Acidizing in Carbonate Reservoir
, M.Sc. Thesis Sharif University of Technology ; Ayatollahi, Shahabeddin (Supervisor) ; Ghotbi, Sirous (Supervisor)
Abstract
Matrix acidizing as a well stimulation technique is performed to increase the production index by increasing the permeability and removing the formation damage in the near wellbore region. However, several challenges such as corrosion of the tubulars and iron precipitation in the formation are hindering this process. To encounter these challenges, different chemicals, or additives, such as corrosion inhibitors and iron control agents are added to the acid solution. Carbonate acidizing has been carried out using HCl-based stimulation fluids for decades. However, at high temperatures, HCl does not produce satisfactory results because of its fast reaction, acid penetration, and hence surface...
Experimental Investigation of Brine Salinity Effect on Relative Permeability Curve in Tight Reservoir
, M.Sc. Thesis Sharif University of Technology ; Shad, Saeed (Supervisor)
Abstract
An experimental study was conducted to investigate the reduction of relative permeability caused by salt precipitation. Series of isothermal sand pack flood experiments were conducted on a sand pack composed of several minerals and relative permeability of the involved phases were determined. This compose was taken south of Iranian reservoir properties. A stainless steel sand-pack of 2.5cm internal diameter and 19.2 cm long was designed and built for experimental procedure. There are is different methods to determine relative permeability of porous media, According to available facilities in the lab and objective of this study unsteady state have been chosen to determine relative...
Experimental investigation on the fault diagnosis of permanent magnet DC electromotors
, Article Insight: Non-Destructive Testing and Condition Monitoring ; Volume 55, Issue 8 , August , 2013 , Pages 422-427 ; ISSN: 13542575 ; Ebrahimi, A ; Heydari, M ; Asadi, M ; Alasti, A ; Sharif University of Technology
Abstract
In this paper, an algorithm for fault diagnosis of permanent magnet DC electromotors.has been investigated, based on vibration and electrical current monitoring. Several permanent magnet DC electromotors.with previously determined faults have been prepared and the vibration, current and speed data have been measured. The relationship between certain related measured data and faults has been determined. A fault diagnosis algorithm has been developed in this research based on these relationships. This algorithm can be used in mass production lines for quality control
Experimental investigation of thermal resistance of a ferrofluidic closed-loop pulsating heat pipe
, Article Heat Transfer Engineering ; Vol. 35, issue. 1 , 2014 , pp. 25-33 ; ISSN: 01457632 ; Mohammadi, M ; Ghahremani, A. R ; Shafii, M. B ; Mohammadi, N ; Sharif University of Technology
Abstract
For the present article, a pulsating heat pipe (PHP) is fabricated and tested experimentally by bending a copper tube. The effects of working fluid, heat input, charging ratio, inclination angle, magnets location, and ferrofluid (magnetic nanofluid) volumetric concentration have been investigated on the thermal performance of this PHP. Experimental results show that using ferrofluid as a working fluid improves the thermal performance of the PHP significantly. Moreover, applying a magnetic field on a ferrofluidic PHP reduces its thermal resistance. By changing the inclination angle of the PHP from vertical mode to angles close to the horizontal mode, the present PHP has a constant and...
Experimental investigation of the roles of blood volume and density in finger photoplethysmography
, Article IEEE Sensors Journal ; Volume 13, Issue 5 , 2013 , Pages 1397-1398 ; 1530437X (ISSN) ; Zahedi, E ; Attar, H. M ; Aghajani, H ; Sharif University of Technology
2013
Abstract
Using simultaneous photoplethysmogram (PPG) and pulse transducer signals from the same finger, a high correlation (Mean: 98.6, STD: 1) is obtained between the AC part of the PPG and estimated volume changes (after normalization). These results point to the fact that in the resting fingertip, PPG signal variations are only due to volume changes and that blood density does not change thus has no contribution
Experimental Investigation of Three Dimensional Turbidity Current
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor)
Abstract
Dense underflows are continuous currents which move down slope due to the fact that their density is heavier than ambient water. Driven by density differences between the inflow and clear water in the reservoirs, the density current plunges the clear water and moves on the bed. While density currents flowing on a sloping bed, the vertical spreading due to water entrainment plays an important role in determining the propagation rate in the longitudinal direction. These currents are similar to wall-jet currents according to structure of the flows but are complicated relative to wall-jet currents due to the existence of density difference. Characteristics of the density current sometimes are...
Fabrication And Experimental Investigation of A New Vehicle Cooling System Using Vapor-Jet Refrigeration Cycle
, M.Sc. Thesis Sharif University of Technology ; Farhanieh, Bijan (Supervisor)
Abstract
Today, the world energy crisis, the need to optimize its consumption and discussion to reduce fuel consumption has become a vital issue. The conventional vehicle air conditioning system due to compressor in refrigeration cycle, which has causes a severe loss in engine useful power, increasing fuel consumption, etc. Therefore, the main goal of this project is the feasibility of the vehicle cooler replacement with the vapor jet refrigeration cycle. In this cycle, the energy required for completing the refrigeration cycle is provided from the heat of the water inside the radiator that is possible with conventional refrigeration cycle. The first stage of this project includes design and...
Investigation of Micro Heat Pipe Performance Using Nano-Fluid as Working Fluid
, M.Sc. Thesis Sharif University of Technology ; shafii, Mohammad Behshad (Supervisor) ; Saboohi, Yadollah (Co-Advisor)
Abstract
Thermal management of micro-electronic devices is a contemporary issue which is increasingly gaining importance in line with the advances in packaging technology. Immediate and consistent multi-disciplinary research is needed to cater to the prevailing trends of net power and flux levels of upcoming micro-electronics products. Material science, packaging concepts, fabrication technology and novel cooling strategies are some of the key areas requiring synchronal research for successful thermal management. Focusing on the latter area, this thesis presents an experimental study on thermal performance of Micro-Closed Loop Pulsating Heat Pipes (MCLPHPs) which are new entrants in the family of...
Investigation on the Effect of Improper Lubrication on the Performance of Rolling Element Bearings
, M.Sc. Thesis Sharif University of Technology ; Behzad, Mehdi (Supervisor) ; Hoviattalab, Maryam (Supervisor)
Abstract
In this project, the effect of improper lubrication on vibrational behavior of rolling element bearings is investigated. Different lubrication conditions were deliberately produced using three oils with different viscosity grades on a bearing at different loads and speeds. The acceleration of bearing vibrations were measured, then analyzed by means of squared envelope analysis, a special case of cyclostationary analysis. The results and their comparison showed that decrease in lubricant’s viscosity grade can lead to an increase in magnitude of cyclic frequencies equal to cage frequency and its harmonics. This observation can be helpful in detection of lubricant degradation and in...
Experimental Study on Behavior of Turbidity Currents with Obstacle
,
M.Sc. Thesis
Sharif University of Technology
;
Afshin, Hossein
(Supervisor)
;
Firoozabadi, Bahar
(Co-Advisor)
Abstract
Turbidity currents are produced when a particle laden fluid flows under the lighter ambient fresh fluid. The streaming of particle laden fluid is called turbidity current and this kind of currents is the major mechanism for sediment transportations in lakes and oceans. In the present research, the main concentration is on the effect of obstacle on the behavior of turbidity current. A series of laboratory experiments were carried out with various obstacle heights, shapes and different inlet densimetric Froude numbers. In each experiment, velocity profiles upstream and downstream of the obstacle were measured, using an ADV (Acoustic Doppler Velocimeter). Kaolin was used as the suspended...
Core-Scale Modeling and Experimental Study of Surfactant Flooding due to Enhanced Oil Recovery in Carbonate Rocks
, M.Sc. Thesis Sharif University of Technology ; Ghazanfari, Mohammad Hossein (Supervisor) ; Jamshidi, Saeed (Co-Advisor)
Abstract
Chemical flooding such as surfactant flooding in oil reservoirs can change the wettability and interfacial tension between oil and water and so reduce the residual oil saturation in the reservoir. Some of these materials can be adsorbed a lot on the surface of carbonate rocks, so it is difficult to predict the oil recovery factor in such process. Therefore it is necessary to survey the adsorption amount of surfactants in chemical EOR injections.In this thesis, the adsorption of a nonionic surfactant on the surface of carbonate rock is experimented and the proper model is obtained. Then the surfactant is injected in a core saturated with oil to observe the efficiency of this surfactant in...
Experimental Investigation of Performance of Tack Coats
, M.Sc. Thesis Sharif University of Technology ; Tabatabaee, Nader (Supervisor)
Abstract
In this study performance of tack coat (thin layer bonding asphalt concrete layers) was evaluated. The shear strength of tack coat layer was considered as its measure of performance. Direct shear tests were conducted on two layered HMA specimens. The test variables included the type of tack coat material, application rate (amount of residual bitumen per unit area), substrate condition, normal stress and shear loading rate. Four types of liquid asphalt (CSS, CRS, modified CRS and MC-250) were applied as tack coat. Three substrates conditions were used in the tests. These were 3-days old, 17-days old and long term aged substrates were used. It was found that optimum application rate depends...