In this study, instability and failure in complex fluids (Elastoviscoplastic fluids) is explored using the classic Considère (F˙ < 0) and stress curvature (σ¨ < 0) criteria. Employing the Saramito model, numerical simulation of the extensional protocol on non-Newtonian fluids is carried out. Validation is firstly performed (with a purely viscoelastic model) and in general found to be in agreement with previous works. Parameter variation of the Bingham number (Bi), capillary number (Ca) and extension rate (ε˙) is then undertaken. It is found out that for Oldroyd-B based fluids, the stress curvature condition almost always occurs from inception of the flow for all cases. Additionally, increasing surface tension has a stabilizing effect on the extending fluid when it is below a critical value, above which it aids breakup. Increasing the yield stress, though, delays the onset of instability, but reduces the final length of the extending filament. At mild to high extension rates, the Considère criterion and the extension at the maximum stress are suit-able indicators of the final extension at strain-to-break(εST B). Furthermore, the rate of the of necking instability till final breakup varies with the εST B at moderate to high ε˙. / I denna studie undersöks instabilitet och misslyckande i komplexa vätskor (Elastoviskoplas-tiska vätskor) med den klassiska Considère (F˙ < 0) och stresskurvatur (σ¨ < 0) kriterier. Genom att använda Saramito-modellen utförs numerisk simulering av det utökade protokol-let på icke-newtonska vätskor. Valideringen utförs först (med en rent viskoelastisk modell) och i allmänhet visar sig överensstämma med tidigare verk.Parametervariation av Bingham-numret (Bi), kapillärnummer (Ca) och förlängningshastighet (ε˙) genomförs sedan. Det har visat sig att för Oldroyd-B-baserade vätskor, uppträder stresskrökningstillståndet nästan alltid från början av flödet i alla fall. Dessutom har ökande ytspänningen stabiliserande effekt på den utsträckande vätskan när den är under ett kritiskt värde, över vilket den underlättar uppbrytning. En ökning av sträckgränsen fördröjer dock instabiliteten men minskar den slutliga längden på det utsträckta filamentet. Vid milda till höga utvidgningshastigheter är Considère-kriteriet och förlängningen vid maximal spänning lämpliga indikatorer för den slutliga förlängningen vid spänning till brott (εST B). Vidare varierar frekvensen av instabilitet i halsen till slutlig upplösning med εST B vid måttlig till hög ε˙.

<p>Hydrogenated castor oil (HCO) crystals as a rheology modifier have been widely used in paints, cosmetics and household products. In this thesis, we are interested in the effect of crystal morphology on the suspension rheology of products. Three major types of micron-sized crystal morphologies have been observed: fiber, rosette and irregular crystal. Fibers show a high aspect ratio with the length ranging from 5 to 33 µm and width around 1~3 µm. The rosette (2~50 µm) is a three-dimensional spherulitic structure with nano-fibrous arms extruding from a heterogeneous central point. Irregular crystals with equivalent diameter ranging from 4 to 84 µm are hard solid and show irregular shapes. There is an additional fourth type of crystal morphology which is a nano-sized fibrous structure that is assumed to be broken down from arms of micron-sized rosettes and fibers. Due to the relatively small amount, the effects of nano-fibrous fragments on rheology were not considered separately in this work.</p> <p>The effect of temperature and shear history on the HCO crystal morphology has been studied. The energy barrier to nucleation for fibers is suggested to be higher than that of rosettes. Irregular crystals are thermodynamically less stable and tend to transform into stable polymorphs. A non-isothermal crystallization study showed that the formation of rosettes and fibers was favored by a slow cooling rate (1°C/min) while the formation of irregular crystals was favored by a fast cooling rate (5°C/min). Shear rates from zero to 100 s^-1 have been applied at cooling rates from 1°C/min to 5°C/min. Nucleation has been found to be promoted with the increase of shear rate. Morphological analysis indicated that the formation of fibers was favored by gentle shear (e.g., 1 s^-1), but fibers can be broken with the increase of shear time.</p> <p>Kinetics of isothermal crystallization of hydrogenated castor oil in water emulsions exhibiting multiple crystal morphologies has been studied in the temperature range of 55°C to 70°C. The induction time of nucleation increases with the increase of the isothermal temperature under which crystallization occurred. A linear increase in induction time with increased temperature was found for both fibers and rosettes. A modified Avrami model was developed by introducing the volume fraction of each type of morphology into three dimensional and one dimensional full Avrami models. It was found that the experimental trends for mixed crystal morphologies could be captured by the modified Avrami model.</p> <p>Due to the difficulty of obtaining samples with a single crystal morphology, rheological studies of suspensions containing mixtures of the three morphologies in a surfactant solution have been undertaken. The viscometry of dilute suspensions has shown that the magnitude of intrinsic viscosity is dominated by the fraction of a crystal morphology type, i.e. fiber > rosette > irregular crystal. A modified Farris model was fitted to the rheology data from mixtures of crystal morphology with interacting particles. A yield stress exists for concentrated suspensions followed by a shear thinning behavior with the increase of shear rate. A power-law relation has been found between yield stress and total particle volume fraction with a constant exponent of 1.5 regardless of crystal morphology.</p> / Doctor of Philosophy (PhD)

The velocity fields around a circular cylinder in a crossflow of drag-reducing polymeric solutions and water were experimentally investigated using a laser-Doppler velocimeter. Measured boundary-layer velocity profiles indicated that the flow parameter controlling the drag on a bluff body in drag-reducing flows is the turbulence intensity rather than the Reynolds number. For turbulence intensity less than 0.7% polymer addition induced delayed separation. For turbulence intensity over 1% the opposite effect was true. Time-averaged velocity profiles of water did not show any significant difference between self-induced and forced oscillatory flows. Heat, mass and momentum transfer of Newtonian and power-law non-Newtonian fluids were theoretically investigated using an implicit finite-difference scheme. The results clearly· indicated that shear-dependent non-Newtonian viscosity controls the entire transport processes of the power-law fluids. For the major portion of the boundary layer, it was found that the more shear thinning the material exhibits, the lower the skin friction and the higher the heat transfer result. Accounting for the motion of the stagnation point provided an improved prediction of heat transfer for Newtonian fluid. / Doctor of Philosophy

The accuracy of the numerical simulation in the prediction of cavitation in cryogenic fluids is of critical importance for the efficient design and performance of turbopumps in rocket propulsion systems. One of the main challenges remains the efficiency in modeling the physics, handling the multiscale properties and developing robust numerical methodologies. Such flows involve thermodynamic phase transition and cavitation bubbles smaller than the global flow structure. Cryogenic fluids are thermo-sensible, then thermal effects and strong variations in fluid properties can alter the cavity properties. The aim of this work is to address the challenge of efficiently modeling cavitating flows when using water and cryogenic fluids. Because of the complexity of the phenomenon, we focus on improving accuracy of the numerical simulation and on proposing some approaches for a strong coupling between numerics and experiments. We first discuss how to simulate cavitation by means of a mixture model. We specifically address two challenges. The first one is associated with the prediction of thermal effect during the phase transition, requiring the solution of the energy conservation equation. The second challenge is associated to the prediction of the number of bubbles, by considering a transport equations for the bubble density. This study is applied to the numerical simulation of a cavitating flow in a Venturi configuration. We observe an improved estimation of temperature and pressure profiles by using the energy equation and the nucleation model. Secondly, we focus on bubble dynamics. Several forms of Rayleigh-Plesset (RP) equations are solved in order to estimate the temperature and pressure during the collapse of the bubble. We observe that, for high Mach number flows, RP modified with a compressible term can predict the bubble behavior more accurately than the classical form of RP. It is necessary to use a complex equation of state for non-condensable gas (van der Waals) in order to have an accurate estimation of the bubble temperature during the collapse phase. We first apply this approach to the water treatment with cavitation, by proposing a model for the estimation of radicals developed during the collapse of the bubble. Secondly, this equation is modified by adding a term of convective heat transfer at the interface between liquid and bubble and it is coupled with a bubbly flow model in order to assess the prediction of thermal effect. We perform a parametric study by considering several values and models for the convective heat transfer coefficient, hb, and we compare temperature and pressure profiles with respect to the experimental data. We observe the importance of the choice of hb for correctly predicting the temperature drop in the cavitating region and we assess the most efficient models. In addition, we perform an experimental study on nitrogen cavitating flows in order to validate numerical prediction of thermal effect, and in order to assess the fundamental characteristics of the nucleation and the transient growth process of the bubble.

No description available.

Fluid-structure interaction (FSI) as the name suggests, is the study of dynamic interaction of both fluid and structure motions. Fluid-structure interaction exists in almost all engineering and science fields. Moreover, the random loading caused by fluid motions in uncertain environment conditions present new challenges to the designers. The objective of the present research work is to develop efficient and robust finite element models to solve fluid structure interaction problems effectively. A key advantage of the displacement based FE M is the flexibility and easiness in modifying the existing efficient numerical solvers, and can also be extended easily to a number of problems. The research work carried out in this thesis can be divided into three parts. In the first part, development of displacement based Lagrangian FE models for acoustic fluids is presented. Here, the displacement fields of the 2-D and 3-DFEs are derived based on the consistently assumed constrained strain fields satisfying irrotationality and incompressibility constraints simultaneously. These elements’ behaviour, in terms of number of zero energy modes, non-zero spurious modes, and the integration order is studied. The inf-sup test is carried out on all the elements to examine the performance of each formulated element. Next, a new class of FEs based on Legendre polynomials is presented. The node point locations in this case are obtained by calculating the zero’s of equation(1- ξ2)L’n(ξ) =0,where,Ln is the Legendre polynomial of order n in one dimension. In the second part, the development of a spectral layer element for studying wave propagation in acoustic fluids is presented. Laplace transform based spectral finite element formulation is developed for studying acoustic wave propagation. The partial differential equations(PDE)are converted to ordinary differential equations(ODE) by taking Laplace transform. The Laplace damping parameter is introduced for easy handling of the numerical Laplace transform(NLT).This Laplace damping parameter removes the “wraparound”problem which is present in shortwave guides due to periodicity of the Fourier transform. Later, a technique is developed through which SFEM stiffness matrix can be added to the FEM dynamic stiffness matrix in the frequency domain. Finally, Uncertainty analysis is carried out to understand the effect of randomness in the design parameters on the system response variability. Here, standard uncertainty analysis procedure called Monte Carlo simulation (MCS) is considered first and later Polynomial chaos expansion(PCE). In this analysis, the gravitational forces, bulk modulus of the fluid, and Young’s modulus of the structure are considered as random input variables in the study. The randomness in the system output is measured in terms of coefficient of variation for each random variable considered.

The research in this thesis was motivated by a desire to understand the mixing properties of quasi-two-dimensional flows whose time-dependence arises naturally as a result of fluid-dynamic instabilities. Additionally, we wished to study how flows such as these transition from the laminar into the turbulent regime. This thesis presents a numerical and theoretical investigation of a particular fluid dynamical system introduced by Kolmogorov. It consists of a thin layer of electrolytic fluid that is driven by the interaction of a steady current with a magnetic field produced by an array of bar magnets. First, we derive a theoretical model for the system by depth-averaging the Navier-Stokes equation, reducing it to a two-dimensional scalar evolution equation for the vertical component of vorticity. A code was then developed in order to both numerically simulate the fluid flow as well as to compute invariant solutions. As the strength of the driving force is increased, we find a number of steady, time-periodic, quasiperiodic, and chaotic flows as the fluid transitions into the turbulent regime. Through long-time advection of a large number of passive tracers, the mixing properties of the various flows that we found were studied. Specifically, the mixing was quantified by computing the relative size of the mixed region as well as the mixing rate. We found the mixing efficiency of the flow to be a non-monotonic function of the driving current and that significant changes in the flow did not always lead to comparable changes in its transport properties. However, some very subtle changes in the flow dramatically altered the degree of mixing. Using the theory of chaos as it applies to Hamiltonian systems, we were able to explain many of our results.

In this scientific work, we use two effective methods : Lie groups theory and the finite element method, to explain why the transition from laminar flow to turbulence flow depends on the variation of the Reynolds number. We restrict ourselves to the case of incompressible viscous Newtonian fluid flows. Their governing equations, i.e. the continuity and Navier-Stokes equations are established and investigated. Their solutions are expressed explicitly thanks to Lie's theory. The stability theory, which leads to an eigenvalue problem is used together with the finite element method, showing a way to compute the critical Reynolds number, for which the transition to turbulence occurs. The stationary flow is also studied and a finite element method, the Newton method, is used to prove the stability of its convergence, which is guaranteed for small variations of the Reynolds number. / Mathematical Sciences / M.Sc. (Applied Mathematics)

Thesis (PhD)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: In this study an equation of state has been developed for the specific purpose of representing systems of simple non-polar spherical and chain-like components and their mixtures for practical applications. To be applied in engineering calculations, the model has to be accurate, be able to represent mixtures with large size asymmetry without the use large binary interaction parameters, and be mathematically simple enough to ensure rapid computations. The model is developed through a sequential evaluation of the statistical mechanical theory of particles and the various approaches available to extend it to real fluid systems. The equation of state developed in this work models the real fluid systems as interacting with a highly simplified two step potential model. The repulsive interactions are represented by a newly developed simplified form of the hard sphere equation of state, capable of representing the known hard sphere virial coefficients and phase behaviour to a high degree of accuracy. This equation has a realistic closest packed limiting density in between the idealised hard sphere fluid random and crystal structure limits. The attractive interactions between the particles are incorporated into the model through a perturbation expansion represented in the form of a double summation perturbation approximation. The perturbation matrix was optimised to have the lowest order in density necessary to still be able to accurately represent real fluid properties. In a novel approach to obtain simple mixing rules that result in the theoretically correct second virial coefficient composition dependence, the perturbation matrix is constrained in such a manner that only the first perturbation term has a term that is first order in density. From a detailed evaluation of the various methods available to represent chain-like non-spherical systems it was finally concluded that the Perturbed Hard Chain Theory provided an ideal compromise between model simplicity and accuracy, and this method is used to extend the equation to chain-like systems. Finally the model is extended to fluid mixtures by uniquely developed mixing rules resulting in the correct mixture composition dependence both at low and high system densities. The newly developed equation of state is shown to be capable of representing the pure component systems to a comparable degree of accuracy as the generally applied equations of state for non-spherical systems found in the literature. The proposed equation is furthermore also shown equal or improve on the predictive ability of these models in the representation offluid mixtures consisting out of similar chainlike or size and energetic asymmetric components. Finally, the computational time required to model the behaviour of large multi-component fluid mixtures using the new equation of state is significantly shorter that that of the other semi-empirical equations of state currently available in the literature. / AFRIKAANSE OPSOMMING: Hierdie werkstuk behels die ontwikkeling van ‘n toestandsvergelyking wat spesifiek gerig is op toepassings in alledaagse, praktiese ingenieurstipe berekeninge en daartoe instaat is om sisteme bestaande uit nie-polêre spferiese- en ketting-tipe komponente en hulle mengsels teKettingteorie (PHCT) die mees geskikde metode is vir hierdie doel en is op die vergelyking toegepas. As ‘n laaste stap in die toestandsvergelykingontwikkelling is daar mengreëls ontwikkel vir die vergelyking wat die korrekte samestellingsafhanklikheid toon vir beide die lae en hoë digtheidskondisies. Die model wat in hierdie studie ontwikkel is, is met verskeie ander bekende toestandsvergelykings, wat daartoe instaat is om nie-spferiese sisteme te modelleer, vergelyk en daar is gevind dat die nuwe model daartoe instaat is om suiwer sisteme net so goed as die bestaande vergelykings te modelleer. Verder is daar ook gevind dat die nuwe vergelyking die modellering van verskeie mensels van kettingtipe komponente en komponente van uiteenlopende groottes of interaksie energieë kan ewenaar of verbeter. Laastens is daar ook gevind dat die tyd nodig vir die modellering van die termodinamiese gedrag van mengsels van ‘n groot hoeveelheid komponente aansienlik korter is vir die nuwe model as die ander bekende semi-empiriese vergelykings. kan beskyf. Om aan hierdie vereistes te voldoen moet die toestandsvergelyking die relevante sisteme akkuraat kan modelleer, slegs klein interaksie parameters benodig om mengsels van komponente met groot verskille in molekulêre groottes akkuraat voor te stel en steeds wiskundig eenvoudig genoeg wees om vinnige berekeninge te verseker. Die vergelyking is ontwikkel deur ‘n sistematiese evaluering van die statisitiese meganiese teorie van partikels en die verskillende metodes om hierdie teorië op werklike sisteme toe te pas. Die toestandsvergelyking beskryf die intermolekulêre interaksie tussen die verskillende komponente met ‘n hoogs vereenvoudigde twee-stap interaksie potensiaal model. Die afstotende kragte tussen die komponente word in ag geneem deur ‘n nuwe vergelyking wat ontwikkel is om die gedrag van ‘n ideale harde spfeer sisteem te modelleer. Hierdie hardespfeermodel is daartoe instaat om die viriale koeffisiënte en die fase gedrag van teoretiese harde spfeer sisteme akkuraat te modelleer, en het ‘n maksimum digtheidslimiet wat tussen teoretiese waardes van ‘n perfek geordende en nie-geordende harde spheer sisteem lê. Die aantrekkinskragte tussen die partikels word beskou as ‘n perturbasie van die harde-spheer vergelyking. ‘n Term bestaande uit ‘n dubbelle sommasiefunksie word gebruik om hierdie perturbasie uitbreiding voor te stel. Die sommasie term is geoptimiseer sodat die finale toestandsvergelyking die laagste digtheidsgraad het wat steeds tot ‘n akkurate voorstelling van die termodinamiese gedrag van werklike sisteme lei. Die sommasiefunksie is so gespesifiseer dat die eerste term van die perturbasie uitbreiding slegs ‘n eerste graadse orde in digtheid het in ‘n unieke benadering om te verseker dat die mengreëls van die toestandsvergelyking die teoreties korrekte samestellingafhanklikheid van die mengselvirialekoeffisiente tot gevolg het. ‘n Deeglike ondersoek van die verskillende metodes om die toepassing van die toestandsvergelyking uit te brei tot die moddellering van nie-spheriese ketting-tipe molekules is gedoen en daar is uiteindelik tot die gevolgtrekking gekom dat die Geperturbeerde Harde

Thesis (MEng) -- Stellenbosch University, 2014. / ENGLISH ABSTRACT: Supercritical fluids are enjoying ever increasing popularity as a solvent medium for extraction, stripping and absorption processes. Being readily tuneable and able to achieve sharp, highly efficient separations, supercritical fluids present an attractive alternative to traditional solvents, while using less intrinsically harmful compounds. Although the potential of supercritical fluids as solvents have been known for more than a century, there are still several areas of uncertainty, one being the hydrodynamics of extraction columns operating under supercritical conditions. This shortcoming can be attributed to the satisfactory performance of modified standard hydrodynamics to approximate column design, along with a predominant culture of overdesign in process engineering. Even though modified subcritical hydrodynamic models provide a good approximation they do not successfully predict the effect of changes in density, viscosity and surface tension of a supercritical fluid, leading to inaccuracies in column design. This study investigates the state of hydrodynamics under supercritical conditions in counter current packed columns discussed in literature, identifies shortcomings in existing literature and devises a way of addressing the said shortcomings. The primary objective of this study is to establish a multipurpose supercritical pilot plant capable of measuring hydrodynamics under supercritical conditions, followed by the secondary objective of measuring preliminary hydrodynamic data to prove the plant can deliver on its design requirements in measuring reliable hydrodynamic data. During a survey of available literature it was found that very little experimental work has been performed on hydrodynamics under supercritical conditions and especially on random packings. Further it is found that the systems investigated in literature were conducted under conditions of significant mass transfer. As mass transfer directly affects flow rates and fluid properties of the fluids in the column, it is vital to use systems with very little to no mass transfer. This ensures the most accurate approach possible when investigating fundamental hydrodynamic behaviour. Finally it was found that there are no well-defined correlations available for a wide range of packings, fluid properties and hydrodynamic phenomena for columns under supercritical conditions. To remedy the shortcomings in hydrodynamic data it was decided that more pilot plant work is required. It was found that no pilot plants available can measure hydrodynamic data. An investigation was performed into retrofitting available pilot plants, plants used by other research groups and commercially available plants. It was concluded that the best option was to salvage the major parts of an existing old pilot plant and use them to construct a new, customized pilot plant. This provides the opportunity of constructing a custom, multipurpose pilot plant capable of use in future research. After an initial concept design a full design of the new pilot plant was performed. The plant consists of two columns of 17 mm and 38 mm inside diameter and 3.5 m and 1.5 m packed height, respectively, and is capable of pressures and temperatures of up to 300 bar and 200°C. Furthermore the pilot plant can measure liquid hold-up, pressure drop, flooding and entrainment in accordance with the objective of measuring supercritical hydrodynamic data. Liquid hold-up was determined by stopping the process and allowing the column to drain, after which the volume drained was measured. To measure the pressure drop an Endress+Hauser Deltabar S PMD75 DP cell was used. Flooding was determined using the measured pressure drop and volumetric rate of column overheads, from where a hydrodynamically inoperable state is defined. Overall entrainment, although unlikely due to the presence of a demister in the column, was investigated by comparing the column overheads to literature phase equilibria. Preliminary hydrodynamic testing was performed using the 38mm diameter column packed with 1/4” Dixon rings. Testing is performed with at 120 bar and 40°C with a CO2 supercritical phase and polyethylene glycol liquid phase with an average molar mass of 400 (PEG 400). The hydrodynamic data gathered showed expected trends, but showed discrepancy with literature due to differences in liquids used, column packing and experimental system between the respective studies. / AFRIKAANSE OPSOMMING: Superkritiese vloeistowwe is besig om toenemende gewildheid as 'n oplosmiddel vir ekstraksie, stroping en absorpsie prosesse te geniet. Hierdie gewildheid is as gevolg van ʼn vermoë om skerp, hoogs effektiewe skeidings te bewerkstellig deur gebruik te maak van ʼn maklik aanpasbare oplosmiddel wat minder intrinsiek skadelik is as tradisionele oplosmiddels. Hierdie voordele lei daartoe dat superkritiese vloeiers as ʼn aantreklike alternatief tot tradisionele oplosmiddels gesien kan word. Alhoewel die potensiaal van superkritiese vloeistowwe as oplosmiddels al vir meer as ʼn eeu bekend is, is nog weinig eksperimentele werk al gedoen oor die hidrodinamiese gedrag van superkritiese gepakte kolomme. Hierdie tekortkoming kan toegeskryf word tot die bevredigende prestasie van aangepaste standaard hidrodinamiese korrelasies gedurende superkritiese kolomontwerp en ʼn oorheersende kultuur van oorontwerp in proses-ingenieurswese. Alhoewel aangepaste standaard hidrodinamiese korrelasies ʼn aanvaarbare benadering bied, beeld dit nie die effek van die veranderde digtheid, viskositeit en oppervlakspanning van ʼn superkritiese vloeistof uit nie, wat lei tot foute in kolomontwerp. Hierdie studie ondersoek die stand van superkritiese hidrodinamika in literatuur, spesifiek in teenstroom gepakte kolomme. Tekortkominge in die bestaande literatuur is geïdentifiseer en 'n metode om die genoemde tekortkominge reg te stel is bedink. Die primêre doel van hierdie studie is om 'n veeldoelige superkritiese loodsaanleg te bou wat tot staat is om superkritiese hidrodinamika te meet, gevolg deur die sekondêre doelwit wat die meet van voorlopige hidrodinamiese data behels, wat sal bewys dat die loodsaanleg voldoen aan ontwerpsvereistes. Tydens 'n opname van beskikbare literatuur was daar gevind dat weinig eksperimentele werk al gedoen is in die veld van superkritiese hidrodinamika, en nog minder oor sogenoemde ongeordende of ‘random’ kolompakkings. Verder is daar gevind dat eksperimente uitgevoer in literatuur slegs bestaan uit stelsels waar beduidende massa-oordrag plaasvind. Aangesien massa-oordrag die vloeitempo en fisiese eienskappe van die vloeiers in ʼn kolom direk beïnvloed, is dit noodsaaklik om gebruik te maak van stelsels met baie min of geen massaoordrag. Dit verseker ʼn akkurate benadering tot die meet van fundamentele hidrodinamiese gedrag. Laastens is gevind dat daar geen hidrodinamiese korrelasies beskikbaar is wat ʼn wye verskeidenheid van kolompakkings, vloeier eienskappe en hidrodinamiese verskynsels onder superkritiese toestande dek nie. Om die tekortkominge in superkritiese hidrodinamika in literatuur aan te spreek, word meer eksperimentele loodsaanlegwerk vereis. Daar is gevind dat geen van die beskikbare loodsaanlegte hidrodinamiese data kan meet nie. Ondersoek is ingestel tot die ombouing van bestaande loodsaanlegte, aanlegte wat gebruik is deur ander navorsingsgroepe en kommersieel beskikbare aanlegte. Daar is tot die gevolgtrekking gekom dat die beste opsie is om ʼn nuwe loodsaanleg self te bou en gebruik te maak van parte uit een van die ou bestaande aanlegte om kostes laag te hou. Sodoende kan ʼn veeldoelige, pasgemaakte loodsaanleg gebou word wat ook vir toekomstige navorsing gebruik kan word. Na ʼn aanvanklike konsep ontwerp vir die nuwe loodsaanleg, is ʼn volledige ontwerp gedoen. Die aanleg bestaan uit twee kolomme van onderskeidelik 17 mm en 38 mm binnedeursnee en 3,5 m en 1,5 m gepakte hoogte, en is in staat om eksperimente by ʼn maksimum druk en temperatuur van tot 300 bar en 200°C uit te voer. Verder is die loodsaanleg in staat daartoe hidrodinamiese data te meet, naamlik die vloeistofophoud in die kolom, drukval oor die kolompakking, kolomvloed en druppel meesleuring. Die vloeistofophoud in die kolom is bepaal deur alle voer tot die kolom te stop en tyd toe te laat vir die vloeistof om te dreineer, waarna die gedreineerde afgetap en gemeet is. Om die drukval te meet word ʼn Endress+Hauser Deltabar S PMD75 DP sel gebruik. Kolomvloed is bepaal met behulp van die drukval oor die kolom en die vloeitempo van die kolom se boonste produkstroom, van waar ʼn hidrodinamies onbruikbare toestand gedefinieer word. Algehele druppel meesleuring, alhoewel onwaarskynlik as gevolg van die teenwoordigheid ʼn ontwasemer in die kolom, is wel ondersoek deur die vloeistofinhoud in die kolom se boonste produkstroom te vergelyk met fase ewewigsdata in literatuur. Voorlopige hidrodinamiese eksperimente is uitgevoer met behulp van die 38mm deursnee kolom gepak met 1/4 " Dixon ringe. Eksperimente is uitgevoer by 120 bar en 40 ° C met 'n CO2 kritiese fase en 'n poliëtileenglikol vloeistof fase met ʼn gemiddelde molêre massa van 400 (PEG 400). Die hidrodinamiese data het verwagte tendense getoon, maar diskrepansies met literatuur waardes. Die verskille tussen die eksperimentele en literatuur data word geregverdig deur die verskille tussen die vloeistowwe, pakking en eksperimentele stelsels wat in die onderskeie studies gebruik is.