Simulacija strujanja vazduha i disperzije zagađivača u prelaznom režimu između strujanja sa mešanjem vazduha i prirodnog strujanja u stambenim zgradama
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Apstrakt
Distribucija vazdušne struje u stambenoj zgradi varira sa periodičnim radom sistema za KGH. U zavisnosti od rada ventilatora KGH, u prostoru se javlja strujanje sa mešanjem vazduha (uključen ventilator), ili stratifikovano strujanje vazduha (isključen ventilator). Ciljevi ove studije su: 1) da ispita koje je vreme potrebno da se stabilizuje vazduh u prostoriji nakon što se uključi/isključi uređaj za centralnu ventilaciju i 2) da se proceni kako razlika u distribuciji zagađivača u gasovitom stanju i u obliku čestica u prostoriji zavisi od režima rada ventilatora. U ovoj studiji vršena su eksperimentalna merenja prostorne distribucije vazdušne struje i koncentracije zagađivača u komori za simulaciju uslova sredine u prirodnoj veličini. Izmereni podaci su zatim poslužili kao osnova za izradu pouzdanog modela računske dinamike fluida (CFD), kojim se ispituju koncentracije gasa i čestica koje zagađuju vazduh u zavisnosti od režima rada mehaničkog ventilatora. Rezultati ukazuju na to da se prelaz između strujanja sa mešanjem i raslojenog strujanja javlja u vremenskoj skali izraženoj u sekundama, što znači da je strujanje u stambenim zgradama prevashodno sa mešanjem ili sa raslojavanjem. Rezultati pokazuju malu prostornu varijaciju gasa obeleživača i čestica u režimu strujanja sa mešanjem vazduha, dok veće vremenske i prostorne varijacije postoje pri raslojenom strujanju. Pored toga, varijacije u koncentracijama čestica veće su od onih u koncentracijama gasova. U određenim delovima prostorije koncentracija čestica pri strujanju sa raslojavanjem vazduha do 30 puta je veća nego pri strujanju sa mešanjem vazduha, što znači da postoji potencijalno velika izloženost česticama kada je ventilator isključen.
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