Thesis-2008-Kulkarni.pdf (26.75 MB)
Three dimensional hydrodynamic modelling of combined free/porous flow regimes
thesis
posted on 2013-08-22, 14:06 authored by A. KulkarniIn the present scenario, as advances in research, technology and engineering
application have been on a rise , thus persuading researchers and engineers to employ
new computer modelling techniques for the design and analysis, mainly due to time,
environmental and economic constraints. Moreover it also forms a basis for any
observed anomalies, when comparing with the simulated and experimental results and
taking steps to develop optimum design strategies. The present research work deals with
the development of novel ftlter designs when employed in aeronautical hydraulic
systems. These pleated cartridge ftlters would be fabricated using eco-friendly fIltering
media supported by unconventional disposable or reusable solid components. The
primary focus of the present research work to develop a robust cost-effective simulating
tools for simulating the results in the hydrodynamic behaviour of the fluid in pleated
cartridge ftlters. As observed in any ftltration process, it comprises of two flow regimes
namely free flow and porous flow regimes. For over five decades, it had been a subject of
intense research and investigation for researchers, scientist and engineers to resolve some
of the critical and vital issues related to filtration process. The main problems, when
compared to others, that are associated with such processes are the free/porous
interfacial constraints along with boundary conditions and their mathematical
representation with respect to the industrial applications.
A three dimensional model has been developed to represent the momentum and
mass conservation for creeping incompressible flow in coupled free/porous flow
regimes. In order to take into consideration the rheological behaviour of the fluid, power
law model has been included, which forms the constitutive equation, and the viscosity of
the fluid has been updated for the highly viscous specially formulated hydraulic fluid. For
any numerical technique of analysis, on vital aspect is the boundary conditions that are
imposed on the surface/volume/edge of the domain under consideration. The free
(Stokes) and porous flow (Darey) regimes have been linked and solved in conjunction
with continuity equations on a perturbed continuity scheme based on the standard
Galerkin weighted residual finite element method.
The perturb continuity UVWP finite element scheme is based On the equal
order interpolation approximations and the discretized working equations are then
transformed into the local coordinate system using iso-parametric mapping. The elements used are linear (8 nodded) hexahedral elements. The integrals in the elemental
stiffness equations were calculated using Gauss-Legendre quadrature. After evaluation of
the members of the elemental stiffness matrix, they are assembled over the common
nodes in the computational grid to obtain a system of algebraic equations. After
substituting the boundary conditions, the system becomes determinate and the algebraic
equations can be solved using a frontal solution method. The described simulations are
carried out using an in-house developed lnte! Visual FORTRAN code. The time
stepping technique used here is second order Taylor-Galerkin method.
The concept of compression permeability model developed by Nassehi et aL
Nassehi et aL, 2005J ( developed for two dimensional case and now extended to three
dimensional case) has been used to into the flow model to take into account the effects
arising due to the mtration area loss in pleated cartridge filters and degree or extent of
compression of the fUter medium. Significant over-use of media material or the need for
changes to the geometric or mechanical design can be identified using the procedures
described.
History
School
- Aeronautical, Automotive, Chemical and Materials Engineering
Department
- Chemical Engineering
Publisher
© Abhijeet Madhukar KulkarniPublication date
2008Notes
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough UniversityEThOS Persistent ID
uk.bl.ethos.507369Language
- en