Eksperimentalna analiza plinsko fokusiranih mikro-curkov

Kušar, Jernej (author), Šarler, Božidar (mentor)

V diplomski nalogi smo izvedli eksperimentalno vrednotenje plinsko fokusiranih mikro-curkov. Eksperimentalno smo z variacijami pretoka fokusirnega plina (zrak) in fokusirane kapljevine (voda) ter ob uporabi 43 različnih kombinacij velikosti premerov zunanje odprtine, notranje kapilare in razdalje med steno in kapilaro ovrednotili 1743 curkov. Reynolds-ovo število curka se je gibalo v območju od 33,62 do 669,35, Weber-ovo število za curek v območju od 1,3 do 33,12, kapilarno število pa v območju od 0,009 do 0,07. Povprečen padec tlaka med notranjostjo šobe in okolico se je gibal v območju med 4 in 252 mbar. Premer nastalega curka se je gibal v območju od 6,39 do 320,7 µm, njegova dolžina pred razpadom pa od 0,13 do 7,84 mm. Izmerjeni rezultati se delno ujemajo z brezdimenzijskim zakonom o skaliranju za curke manjših velikosti. Za območje pretokov, uporabljenih v eksperimentu, so bili izračunane teoretične vrednosti premerov curkov na osnovi enačb iz literature. Razlika med teoretičnimi in eksperimentalnimi vrednostmi premerov se je za večino curkov nahajala v območju med 0 in 16 %, največja razlika je znašala 65 %.

• Language: Slovenian
• Keywords: mikro curek, tokovno fokusirani curki, različni tipi šob, tlačni padec, dolžina curka, premer curka
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FS - Faculty of Mechanical Engineering
• Place of publishing: Ljubljana
• Publisher: [J. Kušar]
• Year: 2024
• Number of pages: XII, 44 str.
• PID: 20.500.12556/RUL-159283
• UDC: 533.697.4:517:620.173.25(043.2)
• COBISS.SI-ID: 202951683
• Publication date in RUL: 05.07.2024

Secondary language

• Language: English
• Title: Experimental analysis of flow-focused micro-jets

Abstract

In this Bachelor thesis, we performed an experimental evaluation of gas-focused micro-jets. We experimentally evaluated 1743 jets by varying the flow of the focusing gas (air) and focused liquid (water) while using one of the 43 different combinations of the outer and inner capillary diameters and the distance between the inner chamber wall and inner capillary top. The gas and liquid Reynolds numbers for jets ranged from 33.62 to 669.35. The jet Weber and Capillary numbers ranged from 1.3 to 33.12 and 0.009 to 0.07, respectively. The average pressure drop between the pressure inside the nozzle and the surrounding pressure varied between 4 and 252 mbar. The diameter of the resulting jet varied in the range of 6.39 to 320.7 µm, and its length before breakup into droplets varied from 0.13 to 7.84 mm. The measured results partially agree with the dimensionless scaling law for smaller jets. For the range of flow rates used in the experiment, theoretical values of jet diameters were calculated based on equations from the literature. The difference between the theoretical and experimental diameter values for most jets ranged from 0 to 16 %, with the most significant difference being 65 %.

• Keywords: micro-jet, flow-focused jets, different nozzle types, pressure drop, jet length, jet diameter