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Title:	Effect of surface tension on fluid flow,heat and mass transfer for natural convection in an open square cavity
Authors:	Norazam Arbin (P58677)
Supervisor:	Ishak Hashim, Prof. Dr.
Keywords:	Heat -- Transmission
Issue Date:	13-Dec-2017
Description:	Heat and mass transfer is important in many engineering fields and industrial sectors. The subject of natural convection in cavities is important in several engineering applications, like solar collectors, cooling of electronic equipment and air flow in buildings. By understanding the fluid flow patterns and characteristics, the optimal heat and mass transfer rates can be achieved. This thesis is concerned with natural convection in a differentially-heated cavity with a free surface. The flow is assumed to be Newtonian, two-dimensional, incompressible and laminar. At the top flat freesurface, Newton's law of cooling is applied. The Boussinesq approximation is applied to the momentum equation. The vorticity-stream function approach for solving the governing equations subject to some appropriate boundary conditions is employed. The finite difference method is used to discretise the equations. The resulting systems of equations are solved by the Successive Over - Relaxation method. All the numerical schemes are programmed in MATLAB. The numerical simulations for the streamlines, isotherms, iso-concentrations, heatlines and masslines together with isocontours of entropy generation are presented graphically. The effect of surface tension which is related to Marangoni number, plays an important role in determining the efficiency of heat and mass transfer mechanism. The heat transfer rate decreases at the cold wall and increases at the hot wall with the combination of surface tension and cooling factor for various fluid types. The flows of heat and fluid circulation are of similar type except at a strong cooling condition. For the case involving doublediffusive convection where the concentration term is considered, the heat and mass transfer mechanisms are strongly dependent on buoyancy ratio and thermal to mass diffusivity ratio. Moreover, the compositional dominated flow makes the transfer rates more efficient for the considered conditions for higher Marangoni number. In addition, the surface tension effect increases the heat and mass transfer rates for all values of the Lewis number for high buoyancy ratio. Decreasing patterns of heat and mass transfer rates are found for low Lewis number for the case of aiding flow which indicates that the surface tension effect suppresses the transfer mechanism across the cavity when a partially heated segment is applied to the cavity. A longer heater segment yields great efficiency of heat and mass transfer rates for various values of the Marangoni number. Furthermore, the obtained results showed the entropy generation is greatly affected by the surface tension effect especially for two configurations of sink-source which contribute to the highest transfer rates for all Marangoni numbers.,Certification of Master's/Doctoral Thesis" is not available
Pages:	165
Call Number:	TJ260.N647 2017 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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