| 1. |
- Moradi Nour, Zeinab, et al.
(författare)
-
Kinematics and dynamics of suspended gasifying particle
- 2017
-
Ingår i: Acta Mechanica. - : SPRINGER WIEN. - 0001-5970 .- 1619-6937. ; 228:3, s. 1135-1151
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of gasification on the dynamics and kinematics of immersed spherical and non-spherical solid particles have been investigated using the three-dimensional lattice Boltzmann method. The gasification was performed by applying mass injection on particle surface for three cases: flow passing by a fixed sphere, rotating ellipsoid in simple shear flow, and a settling single sphere in a rectangular domain. In addition, we have compared the accuracy of employing two different fluid-solid interaction methods for the particle boundary. The validity of the gasification model was studied by comparing computed the mass flux from the simulation and the calculated value on the surface of the particle. The result was used to select a suitable boundary method in the simulations combined with gasification. Moreover, the reduction effect of the ejected mass flux on the drag coefficient of the fixed sphere have been validated against previous studies. In the case of rotating ellipsoid in simple shear flow with mass injection, a decrease on the rate of rotation was observed. The terminal (maximum) velocity of the settling sphere was increased by increasing the ratio of radial flux from the particle boundary.
|
|
| 2. |
- Nita, Satoshi, et al.
(författare)
-
Electrostatic cloaking of surface structure for dynamic wetting
- 2017
-
Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 3:2
-
Tidskriftsartikel (refereegranskat)abstract
- Dynamic wetting problems are fundamental to understanding the interaction between liquids and solids. Even in a superficially simple experimental situation, such as a droplet spreading over a dry surface, the result may depend not only on the liquid properties but also strongly on the substrate-surface properties; even for macroscopically smooth surfaces, the microscopic geometrical roughness can be important. In addition, because surfaces may often be naturally charged or electric fields are used to manipulate fluids, electric effects are crucial components that influence wetting phenomena. We investigate the interplay between electric forces and surface structures in dynamic wetting. Although surface microstructures can significantly hinder spreading, we find that electrostatics can “cloak” the microstructures, that is, deactivate the hindering. We identify the physics in terms of reduction in contact-line friction, which makes the dynamic wetting inertial force dominant and insensitive to the substrate properties.
|
|
| 3. |
- Yada, Susumu, et al.
(författare)
-
Droplet Impact on Surfaces with Asymmetric Microscopic Features
- 2021
-
Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 37:36, s. 10849-10858
-
Tidskriftsartikel (refereegranskat)abstract
- The impact of liquid drops on a rigid surface is central in cleaning, cooling, and coating processes in both nature and industrial applications. However, it is not clear how details of pores, roughness, and texture on the solid surface influence the initial stages of the impact dynamics. Here, we experimentally study drops impacting at low velocities onto surfaces textured with asymmetric (tilted) ridges. We found that the difference between impact velocity and the capillary speed on a solid surface is a key factor of spreading asymmetry, where the capillary speed is determined by the friction at a moving three-phase contact line. The line-friction capillary number Ca-f = mu V-f(0)/sigma (where mu V-theta(0), and sigma are the line friction, impact velocity, and surface tension, respectively) is defined as a measure of the importance of the topology of surface textures for the dynamics of droplet impact. We show that when Ca-f << 1, the droplet impact is asymmetric; the contact line speed in the direction against the inclination of the ridges is set by line friction, whereas in the direction with inclination, the contact line is pinned at acute corners of the ridges. When Ca-f >> 1, the geometric details of nonsmooth surfaces play little role.
|
|
| 4. |
- Larsson, Andreas, et al.
(författare)
-
Collaborative Healthcare Innovation in Sweden
- 2012
-
Ingår i: Sustainable Innovation. - New York : Springer. - 9781461420767 - 9781461420774 ; , s. 49-62
-
Bokkapitel (refereegranskat)abstract
- Abstract in UndeterminedThe medical technology (medtech) industry in Sweden is situated withina complex innovation ecosystem, in which various stakeholders from the public,private and academic sectors need to collaborate to meet demands on effective andeffi cient healthcare. Demographics are changing and those in need of healthcare arenot only larger in numbers than ever but they are also more knowledgeable anddemanding. Increasing innovative performance is crucial in both the private andpublic healthcare sectors, but bold steps forward need to be taken in light of stricterrules and regulations for how healthcare stakeholders should manage both theirinternal processes and the ways in which they interact with other stakeholders in thelarger innovation system. The traditional way in which medtech companies gainaccess to user needs, primarily working through a sales–purchasing relationshipwith the public healthcare sector, is outdated and needs to be replaced with anincreasingly collaborative and cocreative model of healthcare innovation.This chapter describes experiences and lessons learned from InnoPlant, a 3-year(2008–2011) action learning project involving three companies from the Swedishmedtech industry, two county/regional councils responsible for public healthcare,and four academic institutions—carried out within the framework of the SwedishProduct Innovation Engineering program (PIEp). The purpose of the project was toadvance the capability of stakeholders from the public, private, and academic sectorsto collaborate in the cocreation of healthcare innovations.
|
|
| 5. |
- Liu, Jiewei, et al.
(författare)
-
Numerical Simulation of Rapid Expansion of Supercritical Carbon Dioxide
- 2015
-
Ingår i: AIChE Journal. - : Wiley. - 0001-1541 .- 1547-5905. ; 61:1, s. 317-332
-
Tidskriftsartikel (refereegranskat)abstract
- Axisymmetric rapid expansion of supercritical carbon dioxide is investigated in this article. The extended generalized Bender equation of state is used to give a good description of the fluids over a wide range of pressure and temperature conditions. The locations of Mach disks are analyzed and compared with an experimental correlation for the case where there is no plate positioned in front of the nozzle exit. It is found that the disagreement between our numerical results and the experimental formula is very small when the pressure ratio is small, and increases as the pressure ratio increases. It is also found that with different equations of state, the predicted positions of Mach disks do not differ a lot, but the temperature profiles in the chamber differ a lot. The case where there is a plate positioned in front of the nozzle exit is also studied in this article. A universal similarity solution is obtained.
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
- Malik, Amer, et al.
(författare)
-
Modeling and analysis of a phase change material thermohydraulic membrane microactuator
- 2013
-
Ingår i: Journal of microelectromechanical systems. - 1057-7157 .- 1941-0158. ; 22:1, s. 186-194
-
Tidskriftsartikel (refereegranskat)abstract
- Presented in this work, is a Finite Element Method (FEM)-based model for phase change material actuators, modeling the active material as a fluid as opposed to a solid. This enables the model to better conform to localized loads, as well as offering the opportunity to follow material movement in enclosed volumes. Modeling, simulation and analysis of an electrothermally activated paraffin microactuator has been conducted. The paraffin microactuator used for the analysis in the current study exploits the large volumetric expansion of paraffin upon melting, which combined with its low compressibility in the liquid state allows for high hydraulic pressures to be generated. The purpose of the study is to supply a geometry independent model of such a microactuator through the implementation of a fluid model rather than a solid model, which has been utilized in previous studies. Numerical simulations are conducted at different frequencies of the heating source and for different geometries of the microactuator. The results are compared with the empirical data obtained on a close to identical paraffin microactuator, which clearly show the advantages of a fluid model instead of a solid state approximation.
|
|
| 9. |
- Pashkevich, Natallia, 1983-, et al.
(författare)
-
Sustainability through the Digitalization of Industrial Machines : Complementary Factors of Fuel Consumption and Productivity for Forklifts with Sensors
- 2019
-
Ingår i: Sustainability. - Basel, Switzerland : MDPI. - 2071-1050. ; 11:23, s. 1-21
-
Tidskriftsartikel (refereegranskat)abstract
- Increasing the fuel efficiency of industrial machines through digitalization can enable the transport and logistics sector to overcome challenges such as low productivity growth and increasing CO2 emissions. Modern digitalized machines with embedded sensors that collect and transmit operational data have opened up new avenues for the identification of more efficient machine use. While existing studies of industrial machines have mostly focused on one or a few conditioning factors at a time, this study took a complementary approach, using a large set of known factors that simultaneously conditioned both the fuel consumption and productivity of medium-range forklifts (n = 285) that operated in a natural industrial setting for one full year. The results confirm the importance of a set of factors, including aspects related to the vehicles’ travels, drivers, operations, workload spectra, and contextual factors, such as industry and country. As a novel contribution, this study shows that the key conditioning factors interact with each other in a non-linear and non-additive manner. This means that addressing one factor at a time might not provide optimal fuel consumption, and instead all factors need to be addressed simultaneously as a system.
|
|
| 10. |
- Shiomi, Junichiro, et al.
(författare)
-
Low dimensional heat and mass transport in carbon nanotubes
- 2010
-
Ingår i: Proceedings of the ASME Micro/Nanoscale Heat and Mass Transfer International Conference 2009, MNHMT2009. - 9780791843895 ; , s. 337-346
-
Konferensbidrag (refereegranskat)abstract
- This report covers various issues related to heat and mass transport in carbon nanotubes. Heat and mass transport under quasi-one-dimensional confinement has been investigated using molecular dynamics simulations. It is shown that the quasi-ballistic heat conduction manifests in the length and diameter dependences of carbon nanotube thermal conductance. Such quasi-ballistic nature of carbon nanotube heat conduction also influences the thermal boundary conductance between carbon nanotubes and the surrounding materials. The quasi-one-dimensional structure also influences the mass transport of water through carbon nanotubes. The confinement gives rise to strongly directional dynamic properties of water. Here, it is demonstrated that the confined water can be efficiently transported by using the temperature gradient. Furthermore, the simulations reveal the diameter-dependent anisotropic dielectric properties, which could be used to identify intrusion of water into carbon nanotubes.
|
|
