Engineering Commons^™

Desktop Computer Programs For Preliminary Design Of Transonic Compressor Rotors, Brian C. Mcdonald

Theses and Dissertations

A need exist for correlation-based desktop computer programs that predict the flow through transonic compressor rotors with nominal computational time and cost. Modified versions of two desktop computer programs, BOWSHOCK and TRANSROTOR, were used to perform a parametric study on a modem compressor rotor. BOWSHOCK calculates the exit flow properties of a supersonic streamtube through a user-defined compressor rotor. TRANSROTOR calculates flow properties at three stations in a user-defined compressor stage. Modifications to TRANSROTOR included the incorporation of a recently published rotor loss model. Baseline and modified TRANSROTOR versions were run with two modern transonic compressor blades. Results were compared …

Simulation And Analysis Of Wing Rock Physics For A Generic Fighter Model With Three Degrees-Of-Freedom, Ahmed Saad

Theses and Dissertations

Modern fighter designs have been associated with lateral self-excited oscillations own as "Wing Rock". Simulations of wing rock by flow visualization utilities have been encouraged to develop a complete understanding of the fluid mechanism that drives the motion as well as for prediction purposes. Previous wind/water tunnel simulations have been limited to a single degree-of freedom (DoF) in roll. In this study, for the first time, wing rock is computationally simulated in three DoF: roll, sideslip, and vertical motion to study the effect of adding file sideslip and vertical motion. The results are for a generic fighter model consisting of …

A Study Of The Volume Of Fluid Method For Moving Boundary Problems, Marianne Francois

Master's Theses - Daytona Beach

Moving boundary problems are often encountered in engineering and science. One of the methods to solve such problems numerically is the volume of fluid (VOF) method. The VOF method uses an additional field variable/to track the interface using the Eulerian fixed grid. In this work, the VOF method is combined with the Continuum surface force model. The governing flow equations for Newtonian fluids in incompressible flow in two dimensions are solved using the pressure-based algorithm. A linear interface reconstruction algorithm is developed and improved by interpolations. In order to validate the code, the problem of the convection of a two-fluid …

Distribution Of Velocities And Velocity Gradients In Mixing And Flocculation Vessels : Comparison Between Ldv Data And Cfd Predictions, Changgen Luo

Dissertations

Flocculation is an operation of significant industrial relevance commonly encountered in many processes, including water and wastewater treatment. The physico-chemical phenomena of this process is strongly affected by the magnitude of the velocity gradients generated, typically through agitation, in rapid mix devices and flocculation vessels.

In this work the fluid dynamic characteristics of mechanically agitated systems, namely three different types of stirred tanks, which can be used as flocculation vessels, were studied. Both the mean and fluctuating velocities in all three directions were measured by using a Laser-Doppler Velocimeter (LDV). The velocity distribution, fluctuating velocities, power consumption and local velocity …

Vapor-Liquid Phase Equilibria Of Nonideal Fluids With A Ge-Eos Model, Socrates Ioannidis

Dissertations

This study dealt with the prediction and correlation of vapor-liquid equilibria behavior of nonideal fluids. The thermodynamic formalism of the G^E-EoS models, which combines the two traditional methods γ-Φ and Φ-Φ used so far for low and high pressure phase equilibria correlations respectively, has been combined with the 1FG^E model, based on one-fluid theory, to produce a more consistent approach to the phase equilibrium problem.

In the first part of our study we examine the predictive abilities of our model for vapor-liquid equilibria of highly nonideal fluids. The results establish the fact that the Huron-Vidal mixing rule …

Dynamic Unstructured Method For Prescribed And Aerodynamically Determined Relative Moving Boundary Problems, Kamakhya Prasad Singh

Mechanical & Aerospace Engineering Theses & Dissertations

A new methodology is developed to simulate unsteady flows about prescribed and aerodynamically determined moving boundary problems. The method couples the fluid dynamics and rigid-body dynamics equations to capture the time-dependent interference between stationary and moving boundaries. The unsteady, compressible, inviscid (Euler) equations are solved on dynamic, unstructured grids by an explicit, finite-volume, upwind method. For efficiency, the grid adaptation is performed within a window around the moving object. The Eulerian equations of the rigid-body dynamics are solved by a Runge-Kutta method in a non-inertial frame of reference. The two-dimensional flow solver is validated by computing the flow past a …

Agitation Requirements For Complete Liquid Dispersion In Liquid-Liquid-Gas Systems, Emad Ahmad Abu-Hakmeh

Theses

A number of studies have been published in the literature on the determination of the agitation intensity at which two immiscible liquids become completely dispersed in mechanically agitated vessels. However, no information is currently available on the agitation intensity required for the complete dispersion of two liquids in the presence of an additional gas phase. Therefore, the main objective of this study was to experimentally determine the minimum agitation speed for complete liquid-liquid dispersion, N_cd, in liquid-liquid-gas systems as a function of gas flow rate, impeller type, impeller size, and impeller off-bottom clearance. The minimum agitation speed was …

Agitation Requirements For Complete Drawdown Of Floating Solids In Stirred Tanks, Joseph Philemon Mmbaga

Theses

The agitation requirements for complete drawdown of floating solids in mechanically agitated tank vessels has been studied both theoretically and experimentally.

A semi-theoretical equation has been derived on the basis of Kolmogoroff's theory of isotropic turbulence to determine the minimum impeller speed required for drawdown. The equation contains one adjustable parameter which has been found to be a function of the impeller type and position in the tank vessel.

The equation was tested using various vessels and impeller configurations. The solid phase consisted of high density polyethylene (density = 897kg/m³), low density polyethylene (density = 840kg/m³) …

An Adaptive Remeshing Finite Element Method For High-Speed Compressible Flows Using Quadrilateral And Triangular Elements, Gururaja R. Vemaganti

Mechanical & Aerospace Engineering Theses & Dissertations

In this study a new adaptive remeshing method for high speed compressible flow analysis is presented. The method uses quadrilateral elements where possible, and triangles are introduced as needed. The primary goal of this study is to develop a remeshing method which uses both the concepts of unstructured and structured meshes for the finite element analysis to predict accurate aerodynamic heating in problems related to high speed viscous flows. The remeshing method uses a solution based on an old mesh to create a new mesh based on an advancing front technique. In the present implementation, a structured mesh of quadrilaterals …

Stability Of Bicomponet Polymeric Liquids In Poiseuille Flow, Chin-Chang Jeng

Theses

Polymer processing, involving two or more components, has become more popular recently in industrial plants. However, product Quality is affected very much by the fluid stability. Some theoretical and experimental results concerning Newtonian and non-Newtonian flow in rectangular coordinates, have been published, and the fluid-fluid interfaces were observed to be unstable by some researchers.

In this paper, the linear stability of bicomponent non-Newtonian fluids flowing in a cylindrical tube was investigated by using the Ellis model. Only the very long wave and the axisymmetric disturbances were considered. The Ellis zero-shear-rate viscosity ratio, m( = η02 / η01 )destabilizing. The half-zero-shear-rate-viscosity …

The Slow Settling Of A Sphere In A Viscous Fluid In The Proximity Of A Corner, Joseph Kisutcza

Theses

Experimental settling velocities for three different sizes of Delrin spheres in Ucon lubricant were determined at 20.2 degrees Celsius in order to confirm the validity of a theoretically derived equation for the settling of a sphere in the proximity of a corner. The experiments were conducted in a wedge shaped column with a circular sector base, filled with the viscous fluid, where the angle of the wedge was varied for experimental purposes. The distance from the wedge apex to the particle was also changed for the different runs.

The experimental data gave a good approximation of the values evaluated by …

The Settling Of Particles In A Square Contained Medium, Richard S. Matyas

Theses

Stokes' Law, has been standardly utilized to calculate the terminal velocity of falling particles. However, the limitation of Stokes' Law is that it does not take into account the container walls and their resulting drag forces. Extensive work with additional drag due to cylindrical container walls has been examined by many investigators. The classical and earliest is the well know Ladenburg Correction which cannot be utilized with non-cylindrical containers. This experimental thesis examines the analog of the Ladenburg relationship for a square container. This experimental thesis was undertaken to experimentally determine the value of the constant K₁ for a …

A Study Of Fluid Flow Entering A Sharp-Edged Channel, Rocco Racano

Theses

Experimental investigations were carried out on an newtonian fluid In the two dimensional case through the regions of a sharp-edged entrance and exit. Qualitative and quantitative results were compared to a variation of a two dimensional case of converging flow in a capillary as originally derived by Oka and proposed by Philippoff. In addition velocity profiles were taken in the entrance region. Furthermore, the effect of temperature gradients in the slit region with their resulting optical effects were considered. The methods used to obtain these goals were photoelasticity and streak photography.

Results were four, to be consistent with the theory …

Application Of The Finite Element Method Using The Method Of Weighted Residuals To Two Dimensional Newtonian Steady Flow With Constant Fluid Properties, Mien Ray Chi

Theses and Dissertations

In this thesis we will be concerned with the two-dimensional steady laminar Newtonian fluid flow with constant fluid properties in Cartesian coordinate system. More precisely, we will consider a flow for which the interesting dependent variables, for example, velocity, vorticity, stream function, etc., are expressible as functions of two independent Cartesian coordinates.

Transition From Laminar To Turbulent Flow For A Two-Phase Mixture, Mohammed Sharief Qureshi

Theses and Dissertations

A phase is simply one of the states of matter. Multiphase flow is the simultaneous flow of several phases. Two-phase flow is the simplest case of multiphase flow.

Developing Turbulent Flow In An Annulus, Dwight H. Kelly

Theses and Dissertations

Turbulent flows are encountered in nearly every case where fluid motion is involved. Since turbulent flow through relatively short annular sections occurs frequently in practical applications, e.g., flow through heat exchangers, axial flow turbomachinery and jet aircraft engines, there is a need for detailed information on this subject.

The Development Of Turbulent Flow In The Inlet Region Of Smooth Pipe, Forrest C. Smith

Theses and Dissertations

Turbulent flows are encountered in nearly every case where fluid motion is involved. Turbulent flow in pipes is of great practical interest, and the problem of flow in the entry region is of special importance since the great majority of applications are in the realm of developing flow.

Turbulent Flow In The Entry Region, Chin-Hsiu Li

Theses and Dissertations

When entering into the subject of turbulent flow, it is essential to understand that the kind of flow with which we deal belongs to a particular class known as shear flow. These types of flow comprise flow fields in which relative velocities have been induced by shear stresses rather than by the action of pressure forces. In pipe flow, when the fluid enters through the well-rounded bell from a reservoir or from the calm open air, a uniform velocity distribution occurs at the pipe entrance. Immediately down stream from the entrance of the pipe, the flow is structured with a …

Liquid Particle Interaction With A Normal Shock Wave, Victor George Forsnes

Theses and Dissertations

The atomization of a liquid by an air stream has been an item of much concern in the past, and there have been numerous experimental studies of the process made in an effort to correlate liquid and air- stream physical properties into a general model which will predict the degree of and the time required for atomization for a given physical situation. The breakup of liquid drops, a major portion of the atomization process, finds application in the field of meteorology, where the formation, breakup, and shape of raindrops is an item of much concern; in the field of internal …