0000000001155223
AUTHOR
Mikus Milgrāvis
showing 6 related works from this author
Plakana profila divslāņu indukcijas spoles izveide
2015
Darbā tiek izstrādāta indukcijas spole ar jauna tipa ģeometriju. Galvenais mērķis ir izveidot spoli tā, lai pie tās pēc iespējas tuvāk varētu novietot pastāvīgo magnētu sistēmu un maksimizētu spoles inducēto lauku. Spoles izmēru izvēlei, veikti analītiski novērtējumi. Izveidots spoles ģeometriskajām īpašībām atbilstošs skaitliskais modelis, un modelētie dati salīdzināti ar cita veida ģeometrijas spolēm. Eksperimentālais modelis izveidots laboratorijas apstākļos un tiek pielāgots jau esošam strāvas avotam. Ap spoli izveidota noslēgta cikla ūdens dzesēšanas sistēma. Apskatīta spoles izdalītā un ar dzesēšanas sistēmas palīdzību aizvadītā siltuma bilance. Veikta skaitliska un eksperimentāla mag…
Permanent magnet dipole stirrer for aluminium furnaces
2018
Use of permanent magnet systems for metallurgical applications have been proposed before. We have continued development of such systems by investigation use of single magnetic dipole which is realized as permanent magnet cylinder. Magnet is magnetized orthogonal to its axis and has been mounted to the side of the liquid metal reservoir. System first was modelled using small scale experiment with galinstan melt. Velocity distributions and flow patterns in reservoir using Ultrasound Doppler Anemometer were acquired and will be presented here. Additionally, numerical model using Comsol and Cenos modelling software were developed alongside analytical, non-dimensional estimation calculations. Ex…
Application of AC and DC magnetic field for surface wave excitation to enhance mass transfer
2020
Abstract Refining the metallic melts and removal of contaminants from the free surface may be sped up by increasing the surface area of mass exchange interface. It is relevant to both the case of volatile impurity evaporation in a vacuum as well as the case of chemical reactions when the continuous crust of reaction products should be interrupted. Previously proposed low-frequency AC magnetic field excitation of intense surface waves is limited by skin-effect. The induced sign-alternating forcing at high dimensionless frequency values becomes dominantly pulsing at considerably higher than unity values, delivering time-averaged stirring without intense surface waves. Superimposing DC magneti…
Direct chill casting of aluminium alloys under electromagnetic interaction by permanent magnet assembly
2018
Direct chill casting is one of the methods used in industry to obtain good microstructure and properties of aluminium alloys. Nevertheless, for some alloys grain structure is not optimal. In this study, we offer the use of electromagnetic interaction to modify melt convection near the solidification interface. Solidification under various electromagnetic interactions has been widely studied, but usually at low solidification velocity and high thermal gradient. This type of interaction may succeed fragmentation of dendrite arms and transport of solidification nuclei thus leading to improved material structure and properties. Realization of experimental small-scale crystallizer and electromag…
Nanoparticle dispersion in liquid metals by electromagnetically induced acoustic cavitation
2016
Abstract Aim of this study is to investigate experimentally the effect of magnetically induced cavitation applied for the purpose of nanoparticle dispersion in liquid metals. The oscillating magnetic force due to the azimuthal induction currents and the axial magnetic field excites power ultrasound in the sample. If the fields are sufficiently high then it is possible to achieve the acoustic cavitation threshold in liquid metals. Cavitation bubble collapses are known to create microscale jets with a potential to break nanoparticle agglomerates and disperse them. The samples are solidified under the contactless ultrasonic treatment and later analyzed by electron microscopy and energy-dispers…
Laikā mainīgu magnētisko lauku izmantošana daļiņu izkliedei šķidrā metālā
2017
Metāla matricas kompozīti (MMC) ir materiāli, kas sastāv no metāla matricas un tajā izkliedētām oksīda, keramikas vai citām daļiņām. Tiem var būt unikālas materiāla mehāniskās, termiskās u.c. īpašības. Šajā darbā tiek izstrādāta EM tehnoloģija daļiņu veidoto aglomerātu bezkontakta sagraušanai šķidrā metālā. Lai testētu elektromagnētisko metožu ietekmi uz daļiņu sadalījumu, ir izveidotas vairākas eksperimentālas sistēmas spiediena svārstību radīšanai šķidrā metālā. Eksperimentu sērijās alumīnija un alvas paraugi ar SiC un TiB daļiņām pakļauti AC, DC magnētiskajiem laukiem, kā arī magnētiskā lauka impulsiem. EM iedarbības laikā sasniegta metāla kavitācija. Pēc EM iedarbības daļiņu raksturīgai…