Search results for " fluid dynamics"
showing 10 items of 246 documents
Implementation and application of the actuator line model by OpenFOAM for a vertical axis wind turbine
2017
University of Stavanger has started The Smart Sustainable Campus & Energy Lab project, to gain knowledge and facilitate project based education in the field of renewable and sustainable energy and increase the research effort in the same area. This project includes the future installation of a vertical axis wind turbine on the campus roof. A newly developed Computational Fluid Dynamics (CFD) model by OpenFOAM have been implemented to study the wind behavior over the building and the turbine performance. The online available wind turbine model case from Bachant, Goude and Wosnik from 2016 is used as the starting point. This is a Reynolds-Averaged Navier-Stokes equations (RANS) case set up th…
Membrane Deformation and Its Effects on Flow and Mass Transfer in the Electromembrane Processes
2019
In the membrane processes, a trans-membrane pressure (TMP) may arise due to design features or operating conditions. In most applications, stacks for electrodialysis (ED) or reverse electrodialysis (RED) operate at low TMP (<
Performance improvement of a Savonius water rotor with novel blade shapes
2021
Abstract Savonius water rotor is a prominent drag based turbine able to extract energy available in flowing water with low velocity like river streams, tidal currents or other man made water canals. However, in view of its low performance, an enhanced design of the rotor blades is necessary to better its efficiency. Therefore, the present study aims to improve the efficiency of Savonius rotor by changing the blade design. Different blade shapes were investigated numerically using computational fluid dynamics (CFD). Using conventional design, the peak power coefficient was found to be 0.166 at tip-speed ratio of 0.78. However, the peak power coefficient reaches 0.184 using the optimal blade …
Thermal conductivity of disperse insulation materials and their mixtures
2017
Development of new, more efficient thermal insulation materials is a key to reduction of heat losses and contribution to greenhouse gas emissions. Two innovative materials developed at Thermeko LLC are Izoprok and Izopearl. This research is devoted to experimental study of thermal insulation properties of both materials as well as their mixture. Results show that mixture of 40% Izoprok and 60% of Izopearl has lower thermal conductivity than pure materials. In this work, material thermal conductivity dependence temperature is also measured. Novel modelling approach is used to model spatial distribution of disperse insulation material. Computational fluid dynamics approach is also used to est…
Wall collision and drug-carrier detachment in dry powder inhalers: Using DEM to devise a sub-scale model for CFD calculations
2018
Abstract In this work, the Discrete Element Method (DEM) is used to simulate the dispersion process of Active Pharmaceutical Ingredients (API) after a wall collision in dry powders inhaler used for lung delivery. Any fluid dynamic effects are neglected in this analysis at the moment. A three-dimensional model is implemented with one carrier particle (diameter 100 μm) and 882 drug particles (diameter 5 μm). The effect of the impact velocity (varied between 1 and 20 m s−1), angle of impact (between 5° and 90°) and the carrier rotation (±100,000 rad s−1) are investigated for both elastic and sticky walls. The dispersion process shows a preferential area of drug detachment located in the southe…
Experiments and predictions of the transition of the flow pattern with impeller clearance in stirred tanks
2001
In the present work, the double- to single-loop flow pattern transition in a stirred vessel equipped with a Rushton turbine is investigated by Laser Doppler anemometry (LDA). In particular, the clearance at which such transition occurs is assessed by comparing axial velocity profiles underneath the impeller. Computational fluid dynamics (CFD) simulations of the same system are carried out, by employing the 'inner-outer' fully predictive computation strategy. The comparison of predicted results with the experimental data collected shows that the transition is well reproduced by simulations. A good agreement on the mean velocities is also observed but for the impeller discharge stream angle t…
Effect of material and geometric parameters on natural convection heat transfer over an eccentric annular-finned tube
2019
In this work, the performance of an eccentric annular finned tube heat exchanger under natural convection conditions has been investigated numerically. The objective of the study is to analyse the ...
Membrane distillation heat transfer enhancement by CFD analysis of internal module geometry
2011
Module geometry optimisation can be a crucial matter in all separation processes using selective or hydrophobic membranes, e.g. reverse osmosis (RO) and membrane distillation (MD). In fact the choice of suitable channel shape and size can dramatically affect the performance of the process. With reference to the membrane distillation process, temperature polarization phenomena and pres¬sure drops along the channels largely affect the process efficiency (i.e. the efficient use of temperature driving force for the passage of vapour through the membrane) as well as pressure distribution, module mechanical resistance and pumping costs. Several works have been presented so far in literature on th…
Modelling and simulation of gas-liquid hydrodynamics in mechnically stirred tanks
2007
Abstract Computational fuid dynamics (CFD) is an increasingly important tool for carrying out realistic simulations of process equipment. In the case of multiphase systems the development of CFD models is less advanced than for single-phase systems. In the present work CFD simulations of gas–liquid stirred tanks are reported. An Eulerian–Eulerian multi-fluid approach is used in conjunction with the simplest two-phase extension of the k–ɛ turbulence model. All bubbles are assumed to share the same size. The effect of inter-phase forces on simulation results is separately considered. As concerns drag, it is shown that the sole parameter needed to characterize the dispersed phase behaviour is …
Thermal-hydraulic behaviour of the DEMO divertor plasma facing components cooling circuit
2017
Abstract Within the framework of the Work Package DIV 1 – “Divertor Cassette Design and Integration” of the EUROfusion action, a research campaign has been jointly carried out by ENEA and University of Palermo to investigate the thermal-hydraulic performances of the DEMO divertor cassette cooling system. A comparative evaluation study has been performed considering three different options for the cooling circuit layout of the divertor Plasma Facing Components (PFCs). The potential improvement in the thermal-hydraulic performance of the cooling system, to be achieved by modifying cooling circuit layout, has been also assessed and discussed in terms of optimization strategy. The research acti…