Fluid Dynamic Properties Research Articles

Thermal and velocity slip conditions together with thermal radiative effects on Joule heating mixed convection MHD hybrid nanofluid flow induced by an exponentially shrinking or stretching sheet

ABSTRACT The present study analyzes the mixed convection with magnetohydrodynamic (MHD) flow, Joule heating, and heat transfer in hybrid nanofluids on exponentially stretching or shrinking sheets. The study aims to optimize heat transfer and fluid dynamics properties in engineering and industrial applications. The governing partial differential equations are converted into ordinary differential equations by employing appropriate similarity transformations and then solved using the BVP4C MATLAB tool. In this study, the effects of silver volume fraction, velocity slip, thermal slip, magnetic field, heat generation, Eckert number, and thermal radiation on the skin friction coefficient, Nusselt number, velocity profile, and temperature profile are examined and graphically discussed. The base fluid water contained 2% silver (Ag) and 0.1% titanium oxide (TiO2) nano-particles in this hybrid model. The dual solution was present for a shrinking sheet ( λ < 0 ) when λ ≥ λ c . The skin friction coefficient values decreased by approximately 37%, while the local Nusselt number increased by approximately 3.1% when the velocity slip increased in the first solution. The Nusselt number increased by approximately 0.28% and 12% when the Eckert number and radiative parameter increased, respectively, but decreased by approximately 7.5% and 0.20% when the thermal slip and heat generation increased, respectively.

Centrifugal Compressor Surge in Closed Loop Systems: Initial Modelling and Comparison with Experiments

Abstract Heat pumps are expected to play a primary role in electrification of thermal users in the residential and industrial sectors. Dynamic compressors are widely used in large size heat pumps, thanks to their industrial replicability, compact size, affordable costs, and good performance in terms of efficiency and low acoustic emissions. The instability, which may occur in a compressor installed in closed loop cycle such as in a heat pump, is quite different from the classic open loop configuration involving dynamic compressors. This is mainly due to the complexity of the compressor instability mechanism coupled to a vapor compression system connected with two- phase heat exchangers, having different thermal and fluid dynamic capacitance properties, under a physical feedback loop. The aim of this paper is to investigate the behaviour of a dynamic compressor installed in an innovative heat pump prototype, of laboratory scale, under stable and unstable conditions. A preliminary simple dynamic model of the compression system consisting of a radial compressor, condenser and evaporator, is developed to represent the heat pump compression system, which can capture the unstable behaviour. The evaporator and condenser are modelled using empirical correlations. The preliminary validation of the dynamic model results is done through a dedicated experimental campaign, under different operating conditions. Results show the complexity of the interaction between the centrifugal compressor and the heat pump loop, discerning the different contributions to the time-dependent response of the system, prompting the necessity of a detailed model in the next step of the work.

Using Hydrodynamic Similarity as a Verification Method for Impact Cratering Simulations in the FLAG Hydrocode

Hydrodynamic codes (hydrocodes) are common tools for modeling hypervelocity impacts to provide insight into the physical phenomenon. Hydrocodes can simulate impacts from micrometer to kilometer spatial scales and reach impact velocities difficult to achieve in experimental settings. However, numerical models are approximations, and demonstrating that a numerical method is capable of providing physical results for these models is essential. In this work, we employ a hydrocode verification technique that leverages hydrodynamic similarity, a mathematical property of the conservation equations of fluid mechanics that form the basis for hydrocode models. Using the FLAG hydrocode, we simulate aluminum (Al) and basalt projectiles and targets at spatial scales spanning 7 orders of magnitude (hundreds of micrometers to kilometers). These materials were chosen because Al-6061 is a common material in spacecraft and satellites and basalt is a useful approximation of rocky astronomical bodies. Our results show that hydrodynamic similarity holds for each material model used and across spatial scales. We show that under certain conditions hydrodynamic similarity can apply in the presence of gravity and that similarity does not hold in the presence of strength models. We conclude that the FLAG hydrocode preserves important mathematical properties of fluid dynamics in hypervelocity impacts of Al-6061 and basalt.

In vivo fluid dynamics of the Ventura interatrial shunt device in patients with heart failure.

Interatrial shunts are under evaluation as a treatment for heart failure (HF); however, their in vivo flow performance has not been quantitatively studied. We aimed to investigate the fluid dynamics properties of the 0.51cm orifice diameter Ventura shunt and assess its lumen integrity with serial transesophageal echocardiography (TEE). Computational fluid dynamics (CFD) and bench flow tests were used to establish the flow-pressure relationship of the shunt. Open-label patients from the RELIEVE-HF trial underwent TEE at shunt implant and at 6 and 12month follow-up. Shunt effective diameter (Deff) was derived from the vena contracta, and flow was determined by the continuity equation. CFD and bench studies independently validated that the shunt's discharge coefficient was 0.88 to 0.89. The device was successfully implanted in all 97 enrolled patients; mean age was 70±11years, 97% were NYHA class III, and 51% had LVEF ≤40%. Patency was confirmed in all instances, except for one stenotic shunt at 6months. Deff remained unchanged from baseline at 12months (0.47±0.01cm, P=0.376), as did the trans-shunt mean pressure gradient (5.1±3.9mmHg, P=0.316) and flow (1137±463mL/min, P=0.384). TEE measured flow versus pressure closely correlated (R2≥0.98) with a fluid dynamics model. At 12months, the pulmonary/systemic flow Qp/Qs ratio was 1.22±0.12. When implanted in patients with advanced HF, this small interatrial shunt demonstrated predictable and durable patency and performance.

Dual solutions of magnetized radiative flow of Casson Nanofluid over a stretching/shrinking cylinder: Stability analysis

The enhanced thermal efficiency exhibited by Casson nanofluids offers significant practical applications across various industrial and engineering sectors. This study focuses on the mathematical investigation of the steady magnetohydrodynamic (MHD) boundary layer flow of Casson nanofluid through a stretched/shrinking cylinder, taking into account the effects of suction and thermal radiation. The governing partial differential equations (PDEs) have been subjected to a similarity transformation, resulting in a set of nonlinear ordinary differential equations (ODEs). These ODEs were solved numerically utilizing the code of bvp4c in the software of Matlab which offers high accuracy (4th order). The employed nanofluid model incorporates the effects of Brownian motion and thermophoresis. The present study illustrates the graphical depictions of the impacts of different governing parameters, namely Hartmann (M) number, curvature (γ) parameter, Brownian motion (Nb) parameter, mass suction (S) parameter, thermal radiation (Rd) parameter, and thermophoresis (Nt) parameter, on heat transfer, flow, and mass transfer characteristics. Comprehensive determination and visual presentation of the coefficient of skin friction, local Nusselt number, and local Sherwood number were conducted for a range of estimates of applied parameters. Based on our examination, it has been determined that dual similarity solutions are present within a specific range of mass suction parameters. The relationship between the Casson parameter and various fluid dynamic properties, such as skin friction coefficient, heat transfer rate, and mass transfer rates, has been found to exhibit a decreasing trend. Furthermore, the stability analysis discovered that the first solution exhibits linear stability, whereas the second solution displays linear instability. Additionally, the motivation behind this study is to enhance industrial performance through the optimization of thermal power generation systems, thereby increasing their overall efficiency.

Design, Validation, and Fabrication of a Tailored Electrochemical Reactor Using 3D Printing for Studies of Commercial Boron-Doped Diamond Electrodes.

Boron-doped diamond (BDD) electrodes are the most effective and resistant electrodic materials to perform advanced oxidation processes. Having a reactor that can provide adequate hydrodynamic conditions is mandatory to use these electrodes effectively. In this work, the diamond anode electrochemical reactor (E3L-DAER) is designed to fulfill this necessity. Several features are included to improve its efficiency, like conic inlet/outlet, flow enhancers, and a reduced interelectrode gap. The fluid dynamic validation has been performed using computer fluid dynamics (CFD) calculations, residence time distribution (RDT) curves, and mass transfer analysis. The reactor has been made using a three-dimensional (3D) printing stereolithography (SLA) technique, which allows us to build chemical-resistant reactors with nonstandard and tailored features in a cheap and fast way. The obtained results demonstrate that the designed reactor has the required fluid dynamics properties to perform reliable BDD electrode studies and applications. Finally, a BDD electrode was used to test the production of different oxidants such as persulfate, peroxophosphate, and chlorine-derived species.

On the possibility of engineering social evolution in microfluidic environments

Many species of microbes cooperate by producing public goods from which they collectively benefit. However, these populations are under the risk of being taken over by cheating mutants that do not contribute to the pool of public goods. Here we present theoretical findings that address how the social evolution of microbes can be manipulated by external perturbations to inhibit or promote the fixation of cheaters. To control social evolution, we determine the effects of fluid-dynamical properties such as flow rate or domain geometry. We also study the social evolutionary consequences of introducing beneficial or harmful chemicals at steady state and in a time-dependent fashion. We show that by modulating the flow rate and by applying pulsed chemical signals, we can modulate the spatial structure and dynamics of the population in a way that can select for more or less cooperative microbial populations.

Fluid dynamic properties of shark caudal fin morphology and its relationship to habitats

Fluid dynamic properties of shark caudal fin morphology and its relationship to habitats

Effect of Blade Trimming Length on the Performance of Marine Centrifugal Pump

To study the hydrodynamic characteristics of blade trimming length in centrifugal pumps, Delayed Detached Eddy Simulation (DDES) with nonlinear eddy viscosity was utilized to conduct unsteady calculations on the centrifugal pump. A comprehensive examination of the fluid dynamic properties of the centrifugal pump, including external features, flow conditions, and pressure fluctuations, was carried out. By applying the theory of entropy production, the areas of high energy loss within the centrifugal pump were identified, and the correlations between local entropy production, energy loss, and unsteady flow in different areas with varying blade trimming lengths were analyzed. The results indicate that with the increase in blade trimming length, under rated flow conditions, the head decreases by 1.8%, 3.2%, and 5.7% for different blade trimming lengths, respectively, compared to normal impellers. Similarly, the efficiency decreases by 0.5%, 0.8%, and 1.0% for different blade trimming lengths, respectively. Similar trends were observed under other working conditions as well. As the degree of blade trimming increases, the irreversible losses after the failure of the centrifugal pump also increase significantly, indicating that the flow inside the centrifugal pump becomes disorder. Blade trimming leads to a disorderly fluid flow inside the centrifugal pump, causing an increase in the radial force during operation, which in turn leads to an increase in vibration amplitude and affects its operational stability. Blade trimming failure has a significant impact on the frequency and amplitude of pressure pulsation, resulting in abnormal pressure pulsation and abnormal vibration of the centrifugal pump. Therefore, early warning and diagnosis of blade trimming can be achieved through pressure pulsation monitoring.

Development of open-pore polymer and ceramic foams/Guefoams with tunable fluid-dynamic properties: Application in highly efficient water bacteria removal

The usual replication method for preparing open-pore metal foams using NaCl as a template cannot be successfully applied to the fabrication of foams using either water-based ceramic slurries in which NaCl can be dissolved during processing, or liquid polymers that wet NaCl and leave no interconnecting windows between pores. In this work, we propose to modify the replication process by including a second template, paraffin, which is deposited over the NaCl and serves a dual purpose: (i) it acts as a barrier to dissolution of the NaCl with the matrix precursor, and (ii) it creates size-controllable binding collars between the particles that ensure the formation of interconnecting windows in the foam. The usefulness of the process described here is illustrated by the fabrication of two types of materials: low porosity epoxy and cement matrix foams and Guefoams. As proof of concept, epoxy-based Guefoams were developed for the removal of Escherichia coli in water using iodine-impregnated activated carbon particles as the guest phase. The results indicate that the Guefoams outperform conventional bactericidal particle beds in several aspects, including their ease of handling and their tunable fluid-dynamic properties that enable high bacteria annihilation efficiency.

Proteomics elucidating physiological and pathological functions of TDP-43.

Trans-activation response DNA binding protein of 43kDa (TDP-43) regulates a great variety of cellular processes in the nucleus and cytosol. In addition, a defined subset of neurodegenerative diseases is characterized by nuclear depletion of TDP-43 as well as cytosolic mislocalization and aggregation. To perform its diverse functions TDP-43 can associate with different ribonucleoprotein complexes. Combined with transcriptomics, MS interactome studies have unveiled associations between TDP-43 and the spliceosome machinery, polysomes and RNA granules. Moreover, the highly dynamic, low-valency interactions regulated by its low-complexity domain calls for innovative proximity labeling methodologies. In addition to protein partners, the analysis of post-translational modifications showed that they may play a role in the nucleocytoplasmic shuttling, RNA binding, liquid-liquid phase separation and protein aggregation of TDP-43. Here we review the various TDP-43 ribonucleoprotein complexes characterized so far, how they contribute to the diverse functions of TDP-43, and roles of post-translational modifications. Further understanding of the fluid dynamic properties of TDP-43 in ribonucleoprotein complexes, RNA granules, and self-assemblies will advance the understanding of RNA processing in cells and perhaps help to develop novel therapeutic approaches for TDPopathies.

Exploring the Impact of Oligomerization on Redox Flow Cell Performance

The redox flow battery (RFB) is a promising stationary energy storage technology due to its inherent decoupling of energy and power, long service lifetime, and potential for low-cost manufacturing.1 While current embodiments are constrained by high upfront cost, nonaqueous RFBs may offer a pathway to cost-competitive energy storage systems through higher energy densities;2 however, this concept is at an early stage and several challenges must be overcome. In particular, the development of stable, high-voltage redox chemistries in conjunction with low-cost, selective membranes is needed to mitigate difficult-to-reverse capacity fade and reduced efficiencies. As such, a range of redox-active organic macrostructures, including oligomers (RAOs),3 polymers (RAPs),4 and colloids (RACs),5 have been described in the peer-reviewed literature. Of specific interest are RAOs, which, like the other macrostructures, can be paired with size-exclusion membranes but exhibit electrochemical and fluid dynamic properties that more closely align with monomers. While this proof-of-concept has been demonstrated,6,7 to our knowledge, few studies have systematically evaluated how the molecular properties of RAOs influence their performance in flow cells.In this presentation, we will describe our efforts to understand how the molecular properties of different oligomers influence their behavior in redox flow cells. To this end, we synthesize and characterize a set of model compounds, ranging from monomers to tetramers, that utilize TEMPO as the redox-active unit. We then assess the thermodynamic, kinetic, and transport properties of these compounds using a suite of voltammetric techniques. Subsequently, we characterize the performance and durability of these compounds in symmetric flow cells via electrochemical impedance spectroscopy, DC polarization, and durational cycling. We perform post-test characterization after the cycling experiments to disaggregate molecular- and cell-level sources of capacity fade. We find that, in general, oligomers with increased size exhibit lower diffusivities while maintaining the facile charge transfer characteristics afforded by the appended monomer. These size-dependent variations in mass transport rates directly translate to differences in cell polarization and cycling performance. Time-dependent capacity fade observed during cycling is confirmed by post-mortem analysis. Broadly, these results align with previously developed relationships between molecular size, electrochemical properties, and flow cell performance; we posit that the principles for functionalization and testing utilized here can be applied to other RAOs with improved stability. Acknowledgements This work was supported as part of the Joint Center for Energy Storage Research, an Energy Innovation Hub funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences. B.J.N gratefully acknowledges the NSF Graduate Research Fellowship Program under Grant Number 1122374. Any opinion, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the NSF. The authors thank Jeffrey Kowalski and Katharine Greco of the Brushett Group as well as Yu Cao and Jeffrey Moore of the Moore Group at the University of Illinois for their contributions to conceptualizing the framework and preliminary testing for this work.

Effectiveness of biomechanically stable pergola-like additively manufactured scaffold for extraskeletal vertical bone augmentation.

Objective: Extraskeletal vertical bone augmentation in oral implant surgery requires extraosseous regeneration beyond the anatomical contour of the alveolar bone. It is necessary to find a better technical/clinical solution to solve the dilemma of vertical bone augmentation. 3D-printed scaffolds are all oriented to general bone defect repair, but special bone augmentation design still needs improvement. Methods: This study aimed to develop a structural pergola-like scaffold to be loaded with stem cells from the apical papilla (SCAPs), bone morphogenetic protein 9 (BMP9) and vascular endothelial growth factor (VEGF) to verify its bone augmentation ability even under insufficient blood flow supply. Scaffold biomechanical and fluid flow optimization design by finite element analysis (FEA) and computational fluid dynamics (CFD) was performed on pergola-like additive-manufactured scaffolds with various porosity and pore size distributions. The scaffold geometrical configuration showing better biomechanical and fluid dynamics properties was chosen to co-culture for 2months in subcutaneously into nude mice, with different SCAPs, BMP9, and (or) VEGF combinations. Finally, the samples were removed for Micro-CT and histological analysis. Results: Micro-CT and histological analysis of the explanted scaffolds showed new bone formation in the "Scaffold + SCAPs + BMP9" and the "Scaffold + SCAPs + BMP9 + VEGF" groups where the VEGF addition did not significantly improve osteogenesis. No new bone formation was observed either for the "Blank Scaffold" and the "Scaffold + SCAPs + GFP" group. The results of this study indicate that BMP9 can effectively promote the osteogenic differentiation of SCAPs. Conclusion: The pergola-like scaffold can be used as an effective carrier and support device for new bone regeneration and mineralization in bone tissue engineering, and can play a crucial role in obtaining considerable vertical bone augmentation even under poor blood supply.

On the effects of hybrid surface wettability on the structure of cavitating flow using implicit large eddy simulation

BackgroundSupercavitation flow is characterized by the presence of a supercavity, which can be unstable and cause unwanted motion or even loss of control of an object. To address this issue, flow control techniques are often employed. These techniques aim to manipulate the flow of liquid around the object and improve stability and control. Some of these methods include using control surfaces, injecting fluids, or more advanced techniques such as active flow control or smart materials. MethodThe aim of this study is to use computational methods to investigate the behaviour of supercavitation flow over a Clark-Y hydrofoil with different contact angle patterns (hybrid wettability) inspired by the Namib desert beetle. The hybrid wettability consists of six distinct patterns with a 160-degree contact angle for superhydrophobic surfaces and a five-degree contact angle for superhydrophilic surfaces. To predict the dynamic and unsteady behaviours of the supercavitation flow with a cavity number of 0.4, the implicit large eddy simulation (ILES) technique and Kunz mass transfer model are used. The compressive volume of fluid technique is used in conjunction with dynamic adaptive mesh refinement to track the interface between the vapour and liquid phases. The simulations are conducted using the interPhaseChangeFoam two-phase flow solver within the OpenFOAM framework. This study analyses the time-averaged and instantaneous fluid dynamic properties of the supercavitation flow of the hydrofoil with a hybrid surface, including pressure, velocity, vorticity fields, wake flow, recirculation zone, and liquid volume fraction. In addition, it examines the instantaneous cavity leading edge and flow separation, the vortical flow structure, vorticity stretching and dilatation, spanwise flow details, the creation of a low-pressure zone behind the hybrid hydrofoil, streamwise velocity fluctuations, and the cavity dynamics over an entire cycle. FindingsThe results show that the contact angle has a significant effect on the structure of the supercavitation flow. Specifically, the use of a superhydrophobic surface on the pressure side and trailing edge of a hydrofoil, along with a superhydrophilic surface on the leading edge, can reduce the thickness of the wake zone, the length of the cloud cavity, and flow instability. Additionally, this approach can delay the onset of cavitation.

In-Cylinder Heat Transfer Model Proposal Compatible with 1D Simulations in Uniflow Scavenged Engines

Advanced two-stroke engines are considered as powertrains for range extenders in hybrid electric vehicles due to size, simplicity, cost, and power density advantages. In-cylinder heat transfer is a phenomenon that affects the temperature of burnt gases and fresh air in an internal combustion engine. Compared to four-stroke units, this influence is more critical in two-stroke engines during the scavenging process since the gases velocity field inside the cylinder evolves rapidly in space and time. This study proposes a new convective heat transfer coefficient model beyond those based on Reynolds number calculation with the mean piston velocity. The model uses semi-empirical equations with non-dimensional numbers since it has to be integrated within the frame of a physical engine model, where thermo- and fluid dynamic properties of the gases inside the engine are solved using 0D or 1D approaches. In this particular application, the temperature deviation led to a poor prediction of trapped mass in the cylinder. The proposed convective heat transfer coefficient is calculated using a pseudo-velocity of the gases inside the cylinder based on the mass flow rates in the intake and exhaust ports during scavenging. The experimental results validate the 1D engine physical model, which is then used as initial conditions for CFD simulations. These CFD results are used to deduce the necessary conclusions for enhanced temperature predictability during scavenging, where deviations of less than 2% can be observed and an impact of up to 12% on the in-cylinder trapped mass can be seen.

Minimum fluidization velocity and bed expansion of the inverse fluidized bed

To define the fluid-dynamic properties of inverse fluidized beds, studies of the minimum fluidization velocity and bed expansion were performed in this work. The experiments were performed in an inverse fluidized bed of polypropylene and polystyrene particles in a cylindrical column using water and an aqueous glycerol solution of different concentrations as fluidizing medium. The dependence of the bed porosity on the superficial velocity of the fluid was determined experimentally for all the particles studied and different fluidizing media. The influence of fluidizing medium viscosity and particle density on the expansion of the inverse fluidized bed and on the minimum fluidization velocity was investigated. Comparison of the experimental data for the expansion of the inverse fluidized bed and the values calculated by the Richardson-Zaki correlation for the conventional fluidized bed showed some deviation, but the experimentally determined data were found to follow the shape of the Richardson-Zaki curve. In this paper, a correlation for the expansion of inverse fluidized beds is proposed.

Oпределение потерь конденсата при наличии неуглеводородных компонентов в пластовом газе

Introduction. Effective forecasting of development indicators and further exploitation of oil and gas condensate fields require operational data on the composition and properties of fluids. As part of the work, based on experimental PVT studies and analytical diagrams, the influence of non-hydrocarbon components on the thermodynamic processes of the reservoir mixture of the Mastakh field was determined. Different solubilities of heavy fractions of hydrocarbons in nitrogen and helium have been revealed. Materials and research methods The methodology for conducting thermodynamic studies and adjusting fluid dynamic properties using analytical diagrams can be divided into several stages: preparing recombined samples, conducting PVT experiments, processing research results. Using the methodology of Gazprom VNIIGAZ LLC, the influence of non-hydrocarbon components on condensate losses in the deposit was determined for the conditions of development of the Mastakhskoye field. Research results and their discussion. The Mastakh gas condensate field is confined to the brachyanticlinal structure of the same name. It has a sublatitudinal strike along a closed isohypse. The arch is complicated by dome-shaped uplifts, the most significant of which are the western and eastern ones. The western rise has a fairly flat and extensive arch. The fault has not been opened in any of the wells. However, indirect signs indicate its presence. The amount of undersaturation of the reservoir system is not high (1.15–1.3), high (up to 1.5) and depends mainly on the abnormally high reservoir pressure. Other reasons for this phenomenon may be the peculiarity of the formation conditions of the deposit or the shift of an already formed deposit. In addition, a significant thermodynamic characteristic is the dissolving ability of hydrocarbon and non-hydrocarbon components in the gas composition. For the initial conditions of the Mastakh field, a difference in reservoir pressures between the roof and the gas-water contact can be traced. There is a change in the content of hydrocarbon and non-hydrocarbon components over the area of the deposit. Thus, as a result of comparing the experiments performed, it was established that the presence of nitrogen and helium in the mixture has different effects on the process of precipitation and loss of hydrocarbons in the deposit. Conclusions. Thus, the data obtained made it possible to determine the influence of non-hydrocarbon components on condensate losses in the deposit and on changes in the properties of the gas condensate system during the development of the Mastakh field. The different degrees of solubility of condensate in the presence of nitrogen and helium, as well as their effect on reservoir losses of hydrocarbons at the stages of pressure reduction, were determined.

In-line measurements of the physical and thermodynamic properties of single and multicomponent liquids.

Microfluidic devices are becoming increasingly important in various fields of pharmacy, flow chemistry and healthcare. In the embedded microchannel, the flow rates, the dynamic viscosity of the transported liquids and the fluid dynamic properties play an important role. Various functional auxiliary components of microfluidic devices such as flow restrictors, valves and flow meters need to be characterised with liquids used in several microfluidic applications. However, calibration with water does not always reflect the behaviour of the liquids used inthe different applications. Therefore, several National Metrology Institutes (NMI) have developed micro-pipe viscometers for traceable inline measurement of the dynamic viscosity of liquids used in flow applications aspart of the EMPIR 18HLT08 MeDDII project. These micro-pipe viscometers allow the calibration of any flow device at different flow rates and the calibration of the dynamic viscosity of the liquid or liquid mixture used under actual flow conditions. The validation of the micro-pipe viscometers has been performed either with traceable reference oils or with different liquids typically administered in hospitals, such as saline and/or glucose solutions or even glycerol-water mixtures for higher dynamic viscosities. Furthermore, measurement results ofa commercially available device and a technology demonstrator for the inline measurement of dynamic viscosity and density are presented in this paper.

Computational fluid dynamic simulation for hydrodynamic shear enhanced filtration in multiple shaft disk filtration system

Multiple shaft disk (MSD) filtration system, in which 12 ceramic membrane disks were inserted for creating multiple hydrodynamic shear enhanced filtration, is a promising dynamic filtration technology for water purification. In order to reveal the complex flow pattern and hydrodynamics in the internals as well as key influencing factors, the commercial CFD package FLUENT with the finite-volume method was applied to simulate the fluid flow and calculate the shear stress. Via CFD simulations, the quantitative and qualitative properties of fluid dynamics could be obtained, which was benefited to understand the multiple flow field and hydrodynamic shear performance. The higher rotating speed of ceramic membrane disk clearly improved the velocity magnitude, shear stress and turbulence, thus significantly enhancing the filtration performance. A modified mathematical model was proposed to compute the velocity entrainment factor k, which could be used to evaluate the influence of the ceramic membrane disk on fluid. The rightmost region of MSD possessed the most intense velocity magnitude, shear stress and static pressure, thus the corresponding ceramic membrane disks (disks 6 and 11) own the highest permeate flux and biggest self-cleaning ability for membrane fouling. As for the inlet flow rate, it had limited effect on the shear stress. Besides, the energy consumption and mechanical efficiency rose with the rotating speed. The pressure values in experiments were in good agreement with those of CFD simulations. The understanding of the hydrodynamic shear enhanced filtration in MSD based on CFD analysis can facilitate the design of dynamic filtration membrane system to improve the module performance and promote the water purification and fouling control.

Development of enhanced three‐dimensional printed packings for scale‐up of distillation columns: A successful case study

AbstractThis publication presents a general approach for the enhancement of packings regarding scalability, separation efficiency, and fluid dynamic properties using three‐dimensional (3D) printing. The methodology is used to develop miniaturized, scalable packings for process development, and scale‐up applications. For this purpose, a 3D printable computer‐aided design version of the Rombopak 9M industrial packing (RP9M‐3D), which is known for its positive scalability properties, was created. An initial characterization by means of computational fluid dynamics simulations and mass transfer measurements reveals positive but also negative design properties. These findings are used to create a more advanced, miniaturized packing structure, the XW‐Pak. The evolved structure is compared to the RP9M‐3D. The simulation and experimental results show that the enhanced packing, which is still in the early stages of development, exhibits higher separation efficiencies with improved scalability properties at the same void fraction and surface area than the RP9M‐3D.