Search results for "Computational Fluid Dynamics"
showing 10 items of 179 documents
Wavelet analysis of experimental results for coupled structural–hydraulic behavior of the EURISOL target mock-up
2009
During test runs of the The European Isotope Separation On-Line (EURISOL) target mock-up performed in December 2008, data were recorded for strain gages and for acceleration sensors. In this paper, the applicability of wavelet analysis for detecting the onset and the status of flow-induced cavitation is investigated for the first time. Even under noisy conditions, the detection of incipient cavitation was possible when combining measurements with data from structural and fluid dynamic simulations. The distribution of coefficients of suitably selected wavelets yields a quantitative measure for the extent of cavitation in the EURISOL target mock-up under representative flow conditions. Withou…
High-order simulation scheme for active particles driven by stress boundary conditions
2020
Abstract We study the dynamics and interactions of elliptic active particles in a two dimensional solvent. The particles are self-propelled through prescribing a fluid stress at one half of the fluid-particle boundary. The fluid is treated explicitly solving the Stokes equation through a discontinuous Galerkin scheme, which allows to simulate strictly incompressible fluids. We present numerical results for a single particle and give an outlook on how to treat suspensions of interacting active particles.
Formulation predictive dissolution (fPD) testing to advance oral drug product development: an introduction to the US FDA funded ‘21st Century BA/BE’ …
2018
Over the past decade, formulation predictive dissolution (fPD) testing has gained increasing attention. Another mindset is pushed forward where scientists in our field are more confident to explore the in vivo behavior of an oral drug product by performing predictive in vitro dissolution studies. Similarly, there is an increasing interest in the application of modern computational fluid dynamics (CFD) frameworks and high-performance computing platforms to study the local processes underlying absorption within the gastrointestinal (GI) tract. In that way, CFD and computing platforms both can inform future PBPK-based in silico frameworks and determine the GI-motility-driven hydrodynamic impac…
Fully developed laminar flow and heat transfer in serpentine pipes
2015
Abstract A serpentine pipe is a sequence of parallel straight pipe segments connected by U-bends. Its geometry is fully characterized by pipe radius, a , bend curvature radius, c and length of the straight segments, l . The repeated curvature inversion forces the recirculation (secondary flow) pattern to switch between two specular configurations, which may enhance mixing and heat or mass transfer with respect to a constant-curvature pipe at the cost of an increase in pressure drop. In the present work, fully developed laminar flow and heat transfer in serpentine pipes were investigated by numerical simulation. The curvature δ = a / c was made to vary between 0.1 and 0.5 while the paramet…
Influence of the porosity profile and sets of Ergun constants on the main hydrodynamic parameters in the trickle-bed reactors
2014
Abstract The Eulerian multiphase code has been applied for the comparative simulation of the experimental results obtained for varying flow rates of both fluid phases and for systems of various physicochemical properties used in the laboratory trickle-bed reactor (TBR). Therefore six different radial porosity profiles and three sets of the Ergun constants used in the relations defining the interphase momentum exchange have been implemented into the CFD code. The mean relative error of the pressure drop and of the averaged holdup as well as the standard deviation determined with respect to the experiments have been used as the criterion for the validation of the theoretical model. These valu…
CFD Modelling of the Demister in the Multi Stage Flash Desalination plant
2011
Abstract Demisters are used to remove entrained brine droplets from flashed off vapor within the flashing stages of the multi stage flash desalination process (MSF). This is necessary to prevent accumulation of brine droplets on the outside surface of the condenser tubes and contamination of the desalinated water. The aim of this work is to design a new demister with lower pressure drop and unaffected separation efficiency which can be later installed in the flashing stages of the MSF plant and causes reduction in the required heat transfer area. In this work the demister performance is predicted as a function of design (wire diameter), and operating parameters (stage temperature). This obj…
Analysis Based Optimization of Human Powered Vehicle Body
2015
The human powered vehicle market is not only a larger market per unit than the automotive market, but it is one in growth. The main product of this market is the classical bicycle, which is familiar around the globe, but mainly in the urban environment. The bicycle, which in this paper will be considered a human powered vehicle, is slowly gaining ground in the field of urban transportation solutions. This paper analyzes the possibility of optimizing the body of a human powered vehicle recumbent tricycle through continuous fluid dynamics. The vehicle is already designed and built, and is fully functional. The body of the vehicle comes as a necessity to give the operator protection from the e…
Improving the rheometry of rubberized bitumen: experimental and computation fluid dynamics studies
2017
Abstract Multi-phase materials are common in several fields of engineering and rheological measurements are intensively adopted for their development and quality control. Unfortunately, due to the complexity of these materials, accurate measurements can be challenging. This is the case of bitumen-rubber blends used in civil engineering as binders for several applications such as asphalt concrete for road pavements but recently also for roofing membranes. These materials can be considered as heterogeneous blends of fluid and particles with different densities. Due to this nature the two components tends to separate and this phenomenon can be enhanced with inappropriate design and mixing. Thi…
CFD simulation of gas-liquid hydrodynamics in a rectangular air–lift loop reactor
2006
Computational Fluid Dynamics is an increasingly important tool for carrying out realistic simulations of process apparatuses. As a difference from single phase systems, for multi phase systems the development of CFD models is still at its early stages. Moreover, gas-liquid systems are characterised by an additional complexity level, related to the fact that, as a difference with solid-liquid systems, bubble sizes are not known in advance, being rather the result of formation and breakage-coalescence dynamics, and therefore of complex phenomena related to flow dynamics and interfacial effects. In the present work CFD simulations of gas-liquid air-lift reactors are reported. All bubbles are a…