Makine Mühendisliği Bölümü Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/371

Browse

Now showing 1 - 20 of 34

Exergy analysis of gas turbine power plant in Iraq Al Najaf
(2015) Al-Gburi, Maher
The exergy analysis of Al Najaf power plant of capacity 115.74MW which is located in Iraq will present in this study. The analysis of every component in the system apart was tested in accordance with the laws of mass and energy conversion was one of the main goals of this thesis. As well as we will identify and quantify the sites which have exergy losses. This analysis provides an alternative plan to ensure superior performance of a power plant. The aspects under consideration were the quantitative exergy balance for the entire system and for each component, respectively. At different temperatures, rate of irreversibility of system components, efficiency of exergy and the efficiency flaws were highlighted for each component and for the whole plant. The exergy flow of a material is classified into the groupings of thermal, mechanical and chemical exergy in this study and a stream of entropy-production. Fuel Natural gas of low heating value of 50050 kJ/kg was used as the fuel. The evaluation addressed the question of how the fluctuations in cycle temperatures influence the exergetic efficiency and exergy destruction in the plant. The rate of exergy destruction in the turbine was around 2.75% whereas that in the combustion chamber was about 55.77%. When a 8°C rise was done in the temperature, exergy efficiency for the combustion chamber was calculated to be 49.83%. According to the results of the study, the combustion chamber is found to be chief means of irreversibilities in the plant. Also, it was identified that the exergetic efficiency and the exergy destruction are considerably dependent on the alterations in the turbine inlet temperature. On the basis of these results, recommendations are presented for advancement of the plant
Optimization of the fabrication processes of microfluidic chips by hot embossing
(2015) Ziyara, Abbas Ali İbrahim
Currently, the advent of microfluidics offers promising tools, especially in life sciences, with applications ranging from biological or chemical sensors to organs on chips. Although, this technology contains various other advantages such as reduction in sample and reagent consumption, decrease in reaction times, and improved accuracy, there are still a few number of commercially available microfluidic devices. One of the reasons hampering commercialization of microfluidics is its fabrication cost. Lithography based techniques are commonly used for microfluidic fabrication owing to the high precision. However in lithography based microfluidic fabrication methods manufacturing lead times are often high. Design-to-device period may reach up to several days. Here, micro scaled conventional methods such as micro milling, micro injection molding, or hot embossing are more prominent. In these methods, the cycle time reduces down to hours or even minutes. This in turn reduces the cost per device considerably. This thesis aims to design and construct a low cost hot embossing press and optimize the process parameters for fabrication of microfluidic chips. The hot embossing press was designed as a low cost device, having material cost as low as 224 TL. For testing purposes, we fabricated a mold made of brass using micro milling process. We proved that, we can obtain 200 m wide channels on polymethylmethacrylate (PMMA) substrates, by applying 240 bars or pressure for 6 min. under 180 oC temperature, total cycle time per one chip is found to be 11 min.
Design of micromixer for precision milled microfluidic systems
(2015) Alfakheri, Ali
Mixing in microfluidic systems is a challenging problem since the flow is almost always laminar hence the transport of species depends only on diffusion. In this thesis, a passive micromixer is designed for mixing two miscible liquids in a micro channel. The mixer utilizes series of throttles, which reduce the diffusion length, placed along the mixing channel. Although there are many fabrication techniques to manufacture microfluidics, the throttles constituting the micromixer are specially designed to be fabricated by micromilling. Here, micromilling is particularly chosen because of its flexibility and productivity compared to other microfluidic fabrication methods. For design purposes, firstly the parameters affecting the mixing performance are determined. These parameters are defined as the Reynolds number (Re), non-dimensional throttle size and the number of throttles. Then, micromixers are simulated using computational fluid dynamics tools available in COMSOL Multiphysics at different parameter levels. As a result, it is found that micromixers with 15 to 20 throttles can achieve a mixing efficiency greater than 80% in very low Re flows. After optimizing the design, the micromixer is improved by shifting the throttles off the axis of the mixing channel. It is seen that the improvement increases the mixing efficiency to 84%.
Design and analysis of an overconstrained manipulator for rehabilitation
(2015) Aldulaimi, Hassan
A parallel manipulator is a closed loop kinematic chain mechanism that is attached to the base by at least two limbs in parallel. Compared with the serial, the parallel manipulator has higher load-carrying capacities, higher accuracy, higher stiffness and lower inertia. Due to these advantages the parallel manipulator become viable alternative for wide applications, therefore it have been the subject of study of many research during the recent three decades. However, these kinematic closed loops also have some disadvantages, such as limited workspace, complicated forward kinematics, high cost and complicated structures. To overcome these disadvantages parallel manipulators with less than 6-DoF can be used. Also, designing a parallel manipulator with less than six degree of freedom for a subspace can relatively reduce the complexity.This thesis deals with one of the applications of parallel manipulator as a rehabilitation robot. This device is an over –constrained parallel manipulator 5 degree of freedom with 3 legs. This manipulator consists of a moving platform which is connected to a fixed base via three legs. Each leg is made of RRR(RR) (revolute) joints where the first three joint in all legs are parallel and the recent two joint are intersecting .Inverse kinematics of this device including position velocity and acceleration are studied. In addition, the workspace of the parallel manipulator is analyzed. A design optimization is conducted for the prescribed workspace of the device. Finally, this thesis also deals with the dynamic modeling the manipulator using an approach of the principle of virtual work. The equations of motion of the manipulator are derived by considering its motion characteristics. To reduce computations, inverse Jacobian matrices for manipulators are derived to give relations between input and output variables.
Analysis of the oil well impactor mechanism under different conditions
(2016) Mahmood Alkarawi, Walaa Abid
Drilling process is one of vastly used manufacturing in oil and gas industry, there are plenty of studies that are looking for this complex process in academic and industry world. PDC drill bit is an important petroleum equipment in this process, therefore predictions of significant process variable such as torque, cutting force and stress distributions play an important role to keep the equipment life and the safety of the lives of workers. The researchers have found these variables by using experimental techniques which makes the investigation need long period time and have expensive cost. At this point, finite element modeling and simulation become the main to investigate these parameters. It can be expected that finite element Simulations can be used without conducting any experimental studies. This thesis covers a study investigating the effect of parameters on the drill bit, PDC modelling and simulation during the drilling process by using finite element method with software ABAQUS. For this purpose, drilling simulations of the PDC are performed. At the first step, the effect of drilling speed on torque and cutting force is investigated by comparing simulation result with experimental results that are found in the literature review. The effect of load force on torque and the values of rotary speed depend on data from experimental working from field NOOR WELL in south of Iraq are found. In addition, comparison of two different mesh sizes of element is performed and the results are compared with that of the literature. Then the effect of applied pressure on the drill bit is shown. Also the effect of kinetic energy and internal energy are considered. Lastly, element point in drill bit is set and the maximum stress results are listed from the beginning of the process to the end. The results corresponding to all of these parameters related with the process of the drill bit are taken as a reference point and then comparison for other impactors are conducted using ABAQUS.
Trajectory tracking control of flexible joint parallel manipulators subject to impact
(2016) Denizli, Mustafa Semih
In this study, trajectory tracking control method for parallel manipulators having joint elasticity is examined and in addition the stability and the performance were investigated when the manipulator is subject to an impact with another object. Firstly, dynamic analysis for the parallel manipulators is carried out and the system equations of motion are derived by using Lagrange technique. Then the system impulse-momentum equations are derived. Moreover, an inverse dynamics control method is presented which is based on an input-output relation between the torques and end-effector position variables. In the case study, a 3-RPR planar parallel manipulator with three legs having joint elasticity is simulated considering an impact with a point mass body and all of these simulations are conducted by Matlab® and Simulink® software programs. After the simulations, it is observed that controller retrieved the desired trajectory and the results are provided at the end of the study.
Design of an overconstrained manipulator for rehabilitation purposes
(2016) Yılmaz, Kuntay
In this thesis, an overconstrained mechanism for upper extremity rehabilitation is introduced. The geometry of the selected manipulator was arranged that it fits the exact motion of the arm upper extremity and acts as an exoskeleton. Inverse kinematics calculations are shown for describing the motion of actuators for a desired arm motion. Lagrange Formulation is used for the inverse dynamic model of the system. Due to the geometry of the manipulator, kinematic and dynamic calculations are applied to the two spherical subspaces of the manipulator using imaginary joints. Workspace analysis has been made to verify the motion that the mechanism needs for the specified rehabilitation tasks.
Numerical study of influence of air ceiling diffusers on room air flow characteristics
(2016) Chowaid, Mehdi
A theoretical study includes details flow turbulence in air-conditioned Turkey spaces with the determination of the boundary conditions depending on the Code of cooling is done in this thesis. Two kinds of two-dimensional and three-dimensional ventilation problems have been considered. Isothermal ventilation in simple rooms. And non-isothermal ventilation with coupled heat or mass transfer. The investigation has studied the flow and thermal boundary conditions for four different diffusers (displacement, grille, slot, and square diffusers). The dimensions of the physical model are (5.16×3.65 m) with (2.43 m high). The supply condition for four diffusers are (displacement (0.0768 kg/s), grille (0.0768 kg/s), slot (0.1410kg/s), square (0.750kg/s)) and temperature at supply for all types is (15° C), the return considered as the type of diffusers has been imposed zero flow pressure and temperature at (24° C). A modified version of a three-dimensional computer program (fluent 6.3.26) by using finite-volume method was used to simulate the complex flow with buoyant inside the model room. They have been investigated numerically by using several turbulence models and the method solution by using k-ε and k-ω models. The numerical results can be divided into: 1. Results which compared with the measured ones obtained from ASHRAE RP-1009 three-dimensional as non-Isothermal and two cases of two-dimensional as Isothermal. 2. There is a good agreement with (k-ω) model gives more accurate fitting and closer to reality, the reason for this is due to the overall average error for displacement ventilation (19.87 % at velocity carves) and (14.20 % at temperature carve). 3. The Effective Draft Temperature (EDT) for four types of diffusers for three orientations simulating the Iraqi condition (east, south, and west) for these models are as follow: The EDT performance of various commonly used turbulence models for complex airflows and temperature distributions with forced ventilation conditions for different buildings in Iraq, also obtain displacement outlet is better than other types. The accuracy of the results can be found at different levels in terms of average temperature.
Feedback lineariztion control of flexible joint parallel manipulators by solving singular acceleration level differential equations
(2016) Abdaljawad Abdaljawad, Harith Mahdi
This study utilizes a certain algorithm where joint drives flexibility is presented for solving singular set of differential equations by specified implicit numerical integration method that is called Backward Euler Formula for more advanced order derivative information. The reason for using such a procedure is that there is singularity presence at the acceleration level inverse dynamics equations because the control torques can't perpetuate a direct effectiveness at the end-effector accelerations as a result of the elastic media. The trajectory tracking control law is utilized for a 3R (revolute joint), three legs planar parallel manipulator. This law linearizes and decouples the system which leads to achieve asymptotic stability by the means of feeding back the positions and velocities of the actuated rotors and joints. The desired path of the end-effector is chosen for the sake of singularity avoidance.
Numerical analysis of turbulent flow and heat transfer with nanofluid in elliptical cross-sectioned duct
(Çankaya Üniversitesi, 2017) Peneklioğlu, Kaan
In this study, varying major to minor axis ratio in an elliptic tube has been investigated numerically under the steady state, forced convection with turbulent heat flow conditions. Constant wall temperature was applied to tube wall. Mainly, hydrodynamically and thermally developed turbulent flow has been investigated. To obtain fully turbulent flow, study was performed Reynolds numbers between 10000 and 100000. Water was used as working fluid in the first part of study. ANSYS Fluent 17.0 tool was used for all simulations. After the end of numerical results, average Nusselt numbers and average friction factors were obtained and they were compared with correlations which are commonly used in the literature. Al2O3 / Water nanofluid was used as working fluid in the second part of study and all simulations were repeated. It is noticed that using of nanofluid increases average Nusselt number significantly. However, it leads to an increase in pressure drop inside the tube. As a result, it causes an increase in average friction factor. According to the results of the study, using of nanofluid increases average Nusselt number almost 13% in all models. At the same time, it causes an increase in average friction factor around 1.7%. It is noticed that different major to minor axis ratios have no significant effect on average Nusselt number and average friction factor. Also, correlations in the form of 𝑁𝑢=𝑎1 ×𝑅𝑒𝑏1 and 𝑓=𝑎2×𝑅𝑒𝑏2 are obtained for average Nusselt number and average friction factor in all models.
Design and optimization of parallel manipulators for rehabilitation
(Çankaya Üniversitesi, 2017) Yavuz, Samet; Makine Mühendisliği
In this thesis, a novel over-constrained parallel manipulator for arm rehabilitation is introduced. This manipulator is a planar-spherical parallel manipulator with five degrees of freedom and four legs for rehabilitation of forearm (wrist, elbow and shoulder joints). First of all, the desired motions are specified. Then, manipulator geometry is proposed to ensure these motions. Inverse kinematic solutions are performed for describing the motion of actuators. Jacobian analysis is done to define singularity conditions and to obtain force-torque relation between user and the manipulator. The manipulator optimized dimensionally by using Firefly Algorithm to provide motions in workspace boundaries without any singularity condition. Obtained dimensional parameters are tested and whole workspace is scanned with several simulations to ensure whether the manipulator provide the given motions in specified workspace boundaries.
Thermodynamic analysis and simulation of parabolic trough solar collector hybrid steam turbine power plant
(Çankaya Üniversitesi, 2017) Al-Attwani, Anwer Hamed Salih
In this study, thermodynamic analysis of a hybrid solar steam turbine power plant is done considering utilization of solar energy which is produced by parabolic trough collectors. Firstly, simulation of the fuel oil fired simple power plant is carried out and compared with conceptually designed improved solar hybrid version of the plant. During the design procedure, connections of the plant with the solar field via a heat exchanger, preliminary design of this heat exchanger, selection of the solar fluid and sizing and orientation of the solar field are performed. Different cases using data from one unit of Wassit thermal power plant, Wassit, Iraq including fuel saving and increasing power (power bosting) modes for different times of the year are considered, simulations are carried out with MATLAB SIMULINK and compared with each other in terms of increasing efficiency, saving fuel oil, increasing output electricity, decreasing environmental pollution and use of water. Also, extra energy which can be utilized by the solar collector field is found for all cases and simulation of the solar field is done for different times of the year and compared in terms of useful power output, overall heat loss coefficient, fluid output temperature, glass and absorber temperatures. v One unit of Wassit thermal power plant has output power equal to 330MW, and contains 3 Stages of turbine, a condenser, 4 low pressure closed feedwater heaters, 3 high pressure closed feedwater heaters and an open feedwater heater. MATLAB simulations performed using the real data from the original power plant for different modes showed that the proposed power plant efficiency is increased in both modes for all schemes. The rate of increasing output power for one case and the fuel saving for the other cases suggested that, integrating parabolic trough collectors with existing thermal power plant is more reliable, less expensive, environmentally friendly and uses less water (in the steam cycle) than getting electric power from only fuel oil powered thermal power plant. The value of efficiency increase, fuel savings and power increase are also compared for different months of the year (summer, spring and winter). Lastly, simple economic analysis is done and the levelized cost of energy is found to be equal to 13.9 cent/kWh and this price is competitive compared among prices of electricity produced in both conventional and renewable power plants.
Stress analysis in single lap joints of composite plates under different loading conditions
(2018) Alsaddam, Samer Kadhım Kareem
In the recent four decades, the demand of the different industries about the light but strong materials which can be used massively, caused a big progress in producing the composite materials. According to the proposed requirement, the necessity of researching about composite materials and the structures which can be constructed based on them is obvious. In this thesis, firstly a brief introduction about the composite materials and their applications are presented. Then, the analyses of three different structured of single-lap single-bolt composite joints are presented. The aforementioned analysis are done because to corroborate the process of simulation which we have done for our design and find features which can be compared together. The analyses are based on stress and deformation. According to the proposed analyses, the T800 carbon epoxy composite material has better performance in terms of deformation under 0- 5KN force. Based on the results which are obtained from the aforementioned analyses, using two supportive plates are used to reduce the effect of load effect on the composite plates. Based on the analyses which are done in chapter 3, a new design is presented in chapter four. According to the results which are done in ANSYS in term of deformation, the performance of our design can be used as an alternative design to replace with the three ones, which are presented in chapter three. Finally, some suggestions as ongoing and future works are presented in chapter five, like, doing experimental test on our design structure.
Suspension design of an unmanned automatic gun shot system placed on a vehicle
(2018) İşcanoğlu, Serkan
tez çalışması ana bölümler olarak, beş kısımdan meydana gelmektedir. İnsansızlaşmanın önemi başlığının altındaki kısımda günlük hayatta insansızlaşmanın önemi ve sonuçları, askeri sahada insansızlaşmanın değeri ve katkıları dahası sonuçları, insansız sistemlerin üstünlük ve buna karşın zayıf olduğu noktalar ve insansız sistemlerin kullanılmasının ahlaki boyutu konuları irdelenmektedir. Askeri sahada insansızlaşma topiği altındaki kısımda, askeri alanda insansızlaşmanın tarihsel boyutu, insansız sistemlerin tanımlanması ve tasnifi, insansız sistemler ve otonomi, hava, kara, deniz ve uzay araçları sınıflarından meydana gelmiş insansız sistemlerin türleri yapıları ve özellikleri; Türkiye'nin sahip olduğu insansız araçlar konuları incelenmiştir. Modern çağdan beri piyade sınıfının ilerlemesi ve savaşlardaki enformatik gelişmeler topiği altındaki bölümde, piyade sınıfının tarihi savaşlardaki kullanılma durumlarına göre irdelemesi yapılmaktadır. En yeni teknolojik ilerlemeler doğrultusunda piyade sınıfının yeni baştan teşkilatlanması başlığı altındaki bölümde planlama, konsept, kadro, araç, silah, teçhizat, enerji gereksinimi ve eğitim alt başlıkları incelenmektedir. Daha sonraki bölümde ise; Türkiye'nin sahip olduğu insansız araçlar, silah yerleştirilebilen araçlar, parametreler, belirlenen bir silah sisteminin monte edilmesi, taşıtın dinamik olarak modellenmesi, süspansiyon seçimi ve süspansiyon tasarımı yapılarak sonuç ve öneriler irdelenmiştir. Bu çalışmada modelleme Solidworks'de yapıldıktan sonra ANSYS programında dinamik analizimiz yapılmış ve geri tepmeli silah tasarımının ne kadarlık bir kuvvete maruz kaldığı ortaya konulmuştur. Aynı zamanda Matlab yazılımında süspansiyon seçiminin yapılması maksadıyla mekanik simülasyon uygulanmıştır.
Numerical study of the effects of geometric parameters on performance of solar chimney power plants
(2019) Nsaif, Osama Sabbar
The aim of the study is to get the best and the most efficient design of Solar Chimney Power Plant (SCPP) considering different chimney and collector parameters. SCPP is one of the most promising applications of solar energy because of the high reliability of the system in addition to the low cost of long-term energy production and low maintenance needs. Because of the reasons above, it has been a focus for researchers to increase efficiency of such systems. Solar chimney power plant is a thermal system containing three basic components; the solar collector, the solar chimney and the wind turbine. SCPP has basic working principles which are the effect of greenhouse, chimney drag and conversion to kinetic energy. The air below the semi-transparent collector (glass) is heated up by the solar radiation which is coming from the top of the collector surface. The heated air moves by buoyancy force to the center of the collector where the turbine is located. The heated air leads to a flow through the turbine and drives the turbine which rotates a generator and electric energy is obtained from that rotation. In this study, a 2-D computational fluid dynamics (CFD) analysis for the entire system of solar chimney power plant is done by using commercial program ANSYS 18.2. After verifying the CFD results of the numerical model with the results of the experimental work and obtaining almost identical results, the main parameters like the height of tower, the diameter of the tower, the tower configuration, the diameter of the collector, the height of collector and the inclination angle of the collector which can effect on performance of SCPP has been changed and the influence of varying these parameters on the effectiveness and performance of the solar chimney system is studied. It is found through this study that all of the chimney and the collector parameters which are mentioned above have a direct impact on the effectiveness and performance of SCPP. Depending on the numerical results, it is found that the height and the diameter of the tower is considered as the most effective parameters which can affect largely on the value of the output power of SCPP and the height and diameter of chimney equal to 3.5 m and 25 cm are the best values considering the performance of the chimney. Also results shows that the diverging chimney configuration is the best tower geometry that can be utilized and it can improve and increase the performance of SCPP largely. The numerical findings shows that the increase of solar collector diameter leads to increasing the output power and the best value for the diameter of the collector is 400 cm (the maximum value). Furthermore, it is concluded that the height and inclination angle of the solar collector has an important effect on the output power and the best design for solar collector parameters is 6 cm height of the solar collector with 0 degree for the inclination angle of the solar collector.
Thermal design and simulation of cooling system for performance improvement of Li-İon batteries for vehicles / Araçlardaki Li-Ion pillerin soğutma performaslarının incelenmesi, tasarım ve test ederek değerlendirilmesi
(2019) Özçelik, Beyrek Baran
Tezin amacı ve kapsamı, sıcaklık değişiminin pil performansı üzerindeki etkisini izlemek ve alternatif soğutma metodolojilerini simüle etmek ile beraber mantıklı bir soğutma sistemi tasarımı önermektir.Farklı soğutma akışkanları, soğutma geometrileri ve ısı transfer yöntemleri incelenmiş ve en uygun olanları simüle edilmiş ve karşılaştırılmıştır. Bu bağlamda alüminyum bateri modülü ve montajlı kanal tipleri sayısal olarak karşılaştırılmıştır. Sayısal modelin, 3C boşalma hızı altında tek bir akünün test edilmesi, zamanın fonksiyonu olarak ısı üretimi ve sayısal model ile karşılaştırılması ile gerçekleştirilmiştir
Numerical modelling of forced convection heat transfer in an open cavity
(2019) Deniz, Ahmet
In this study, combined forced and natural convection heat transfer and fluid flow are examined in an open cavity. The effect of cavity geometries like cavity depth, cavity length, on heat transfer rate is investigated. As a flow parameter, Reynolds number, heat flux, heated wall position and Richardson number effect of the heat transfer are investigated. The cavity left wall is heated with constant heat flux, while other walls are kept at the adiabatic condition. The working fluid is assumed as air with Pr=0.71. For numerical analysis FLUENT Software is used in order to solve incompressible, two-dimensional, steady-state flow. For momentum and energy equations second-order upwind scheme is used. Length to depth ratio and height to depth ratio of the cavity is varied between 0.25
Trajectory control of a delta robot for telescopic mast systems assembly
(2019) Gül, Özgün
In this study, trajectory control of a Delta Robot with three degrees of freedom was carried out. The design of Delta Robot has been examined. The images of the components of the robot are shared with the components. The Telescopic Mast System has been examined and the contribution of Delta Robot on this system has been demonstrated. Delta Robot's Workspace Analysis has been done by " Trajectory Control" and how to follow the path is described. The most efficient path was selected and a trajectory control was done on a determined path. A simulation was created in the MATLAB Simulink Multibody Environment, inverse kinematic codes were placed in the system and a PID control system was added. PID optimization was performed by using MATLAB Optimization Toolbox. This assembly system is simulated with the MATLAB Simulink program and the results are shared.
Kinematic synthesis using fireflyalgorithm and computer-aided analysis of continuous variable valve lift mechanism
(2019) Elkawafi, Aisha
In this thesis, a variable valve lift mechanism is proposed and then the kinematic synthesis has been performed using both MATLAB and Autodesk INVENTOR. Moreover, optimization of the lengths of the links has been done using the firefly algorithm in order to reduce the error between the objective valve lift profile, a polynomial cam profile of race engine, and the calculated profile. The optimized mechanism is simulated again with both MATLAB and INVENTOR and the family of valve lifts for various maximum valve opening are compared and show a good consistency. The valve velocity and acceleration are also calculated and compared with the objective functions. Thus, this mechanically based idea of the schematic variable valve lift system can be translated in the future into the design of a physical system with a selected actuation system to provide the best valve lift depending on the engine demand.
Numerical analysis of nano-fluid flow and heat transfer in ducts
(2019) Al-Tameemi, Hussein Raad Abdulhadi
In this study, turbulent nanofluid flow and heat transfer in a square duct with constant heat flux at the top and bottom surfaces and insulated front a back faces were investigated numerically. Fluent was used for the numerical solution of the governing equations of the problem. To model the turbulence, realizable k- model is used. The finite volume method (FVM) was used to discretize the continuity, momentum and energy equations. Three different types of nanoparticles Al2O3, ZnO, and CuO with different diameters (30, 29, 29 nm) at different volume fractions (in the range of 1% to 4%) were considered. Effects of these parameters on heat transfer rate and flow characteristics in the Reynolds numbers range of 10000 to 35000 were studied. The results of the simulations show a good agreement with the existing experimental correlations. The numerical results show that Al2O3-water has the highest Nusselt number compared to other nanofluids considered while it has the lowest heat transfer coefficient due to low thermal conductivity. It was observed that the Nusselt number increases with the increase in the Reynolds number and the volume fraction of nanoparticles.

Browse

Browsing Makine Mühendisliği Bölümü Tezleri by Issue Date