This thesis aimed at studying the reacting system of boundary layer flow of CuO-Oil- based Nanofluid with heat generation through a vertical permeable surface.
A boundary layer is formed whenever there is a relative motion between the boundary and the fluid. The details of flow within the boundary layer are very important for the understanding of many problems in aerodynamics, including the wind stall, the skin- drag on an object, heat transfers that occur in high speed flight and in naval architecture for the designs of ships and submarines. The concept of boundary layer was first introduced by Prandtl in 1904 and since then it has been applied to several fluid flowproblems.
The science of fluid dynamics encompasses the movement of gases and liquids, interaction of fluid with solid and the study of forces related to these phenomena. It plays an important role in every aspect of our daily life for example from morning bath to evening coffee. It has potential applications in the field of science, engineering, manufacturing, transportation, environment, medicine, energy and others. Flows are important for the existence of natural and technical world. Properties of the fluid, forces acting on the fluid particles and boundaries of the flow domain determine the resultant flow pattern. Deformation of fluids occurs continuously under application of shear stress which makes them isotropic substances. Navier-Stokes equations are the fundamental equations of the fluid that portray the stream as either Newtonian or non-Newtonian Harlow and Amsden.
There is a broad scope of heat transfer applications in numerous industrial processes involving mechanical, electrical and chemical industry. Achieving higher convective rate of heat transfer in thermal systems and processes has always been the challenges facing Scientists and Engineers. As a result, this process requires an immensity amount of vitality to manage the method of fluid heating/cooling and transport of heat. It is known that cooling is necessary for maintaining the preferred performance and steadfastness of an engine.
Heat transfer fluids like water, oil, ethyl glycol and salt water collect and transport heat from the region with high temperature to the region with low temperature. In Automobiles, piston converts the heat generated as a result of the combustion of the fuel into mechanical work and drives the crankshaft in the course of the connecting rod. Continuous heating of the piston without proficient cooling can lead to elevated fuel and oil utilization, harmful exhaust emissions, reduction in engine power output or undeviating engine damage.
Heat transfer fluids are expected to have high thermal conductivity, high volumetric heat capacity, and low viscosity. On the other hand, the heat carrier fluids have low thermal conductivity and affect the proper functioning of the system. In order to guarantee durability, reliability and extend lifespan of an engine, there is need for use of heat carriers’ fluid with improved heat transfer properties. The innovative conception of nanofluid was proposed as a solution to these challenges.
Nanofluid, an improved heat transfer fluid, is a fluid-dispersed which contains nanoparticles of size range (1-100nm). The fluids such as oil, water and ethyl glycol are some of the fluids used in nanofluid. Materials commonly used as nanoparticles are chemically stable metals (copper, gold), metal oxides (CuO, Al O ) and Carbon in various forms (diamond, graphite, carbon nanotubes). The mixture of concentration of nanopaticles into the heat carrier fluids enhances the viscosity of nanofluids and other thermo-physical properties like thermal conductivity, specific heat capacity and density.
Oil based nanofluids is used in the cooling of electronic equipment, nuclear reactors, power transformers and automobile engines. Oil in an engine cushions the bearings in opposition to the shocks of firing cylinders. It serves as lubricant to neutralize the corrosive elements during combustions and prevents the metal surfaces of an engine from rust. It also serves as coolant agent for parts of engine that are not exposed to the water-cooling system.
Metal oxides are commonly used as thermal additives in Nanofluid due to their outstanding properties such as high thermal conductivity and excellent compatibility with base fluid. Al O , TiO , ZnO and CuO are the most popular metal oxides nanoparticles. Nanofluids containing metal oxides have exhibited special potentials in heat transfer applications. Among various metal oxides nanoparticles, CuO has higher thermal conductivity; it is a monoclinic crystal structure and has many attractive properties. CuO particles have spheroid shapes and most of the particles are under aggregate states. And to have an efficient Nanofluid, the particles should have spherical shape to have a higher critical dilute limit.
Excessive concentration of nanoparticles in base fluid at low temperature leads to increase in the density of nanofluid, which is the compactness of nanoparticles, it results into very thick nanofluid and this leads to viscous nano-oil which provides stronger fluid film and the thicker the nanofluid film, the more resistant it will be rubbed from lubricated surfaces. Nanofluids’ viscosity is the measure of its thickness or struggle to flow. It is directly connected with how well oil based nanofluid lubricates and protects surfaces that it moves through. However, very thick nanofluid offers excessive resistance to flow at low temperatures and as a result may not flow quickly enough to those parts requiring lubrication. It is therefore crucial that for nanofluid to be effective, it must exhibit moderate concentration of nanoparticles and the right thermo-physical properties at both the highest and the lowest temperatures which are necessity for proper functional of the engine.
Inhaltsverzeichnis (Table of Contents)
- Chapter 1: Introduction
- 1.1 Background of the Study
- 1.2 Statement of the Problem
- 1.3 Objectives of the Study
- 1.4 Scope of the Study
- 1.5 Significance of the Study
- 1.6 Literature Review
- Chapter 2: Mathematical Formulation
- 2.1 Governing Equations
- 2.2 Boundary Conditions
- 2.3 Dimensionless Parameters
- 2.4 Similarity Transformation
- Chapter 3: Solution Methodology
- 3.1 Numerical Method
- 3.2 Stability Analysis
- 3.3 Convergence Criteria
- Chapter 4: Results and Discussion
- 4.1 Effects of Various Parameters on Velocity, Temperature and Concentration Profiles
- 4.2 Analysis of Skin Friction Coefficient, Nusselt Number and Sherwood Number
- Chapter 5: Conclusion and Recommendation
Zielsetzung und Themenschwerpunkte (Objectives and Key Themes)
This Ph.D. thesis investigates the boundary layer flow of a CuO-oil-based nanofluid with heat generation through a vertical permeable surface. The research aims to provide a comprehensive understanding of the fluid dynamics and heat transfer characteristics of this system, including the effects of various physical parameters such as nanoparticle volume fraction, heat generation parameter, and permeability parameter. The study utilizes numerical methods to solve the governing equations and analyze the resulting data.
- Nanofluid flow and heat transfer characteristics
- Impact of heat generation on fluid behavior
- Influence of nanoparticle volume fraction on fluid properties
- Analysis of boundary layer flow with a permeable surface
- Numerical simulation of fluid dynamics and heat transfer
Zusammenfassung der Kapitel (Chapter Summaries)
Chapter 1 provides an introduction to the research topic, outlining the background of the study, the research problem, the objectives, the scope, the significance of the study, and a comprehensive literature review. Chapter 2 focuses on the mathematical formulation of the problem, establishing the governing equations, boundary conditions, dimensionless parameters, and the similarity transformation used to simplify the equations. Chapter 3 describes the numerical methods employed to solve the formulated problem, including the stability analysis and convergence criteria. Chapter 4 presents the results and discussion of the numerical simulations, examining the effects of various parameters on the velocity, temperature, and concentration profiles, as well as the skin friction coefficient, Nusselt number, and Sherwood number.
Schlüsselwörter (Keywords)
This thesis explores the complexities of boundary layer flow, heat transfer, and nanofluids. Key areas of focus include the dynamics of CuO-oil-based nanofluid flow, heat generation effects, the influence of nanoparticle volume fraction, the role of a permeable surface, and the application of numerical methods for solving governing equations.
- Quote paper
- Ph.D Lateefat Aselebe (Author), 2022, Reacting System of Boundary Layer Flow of CuO-Oil-Based Nanofluid with Heat Generation through a Vertical Permeable Surface, Munich, GRIN Verlag, https://www.grin.com/document/1333582
