TY - JOUR

T1 - An experimental investigation of adiabatic two-phase flow patterns in a slit microchannel with 1:800 aspect ratio

AU - Dementyev, Yu A.

AU - Chinnov, E. A.

AU - Kochkin, D. Yu

AU - Ronshin, F. V.

AU - Evstrapov, A. A.

AU - Gusev, V. S.

AU - Kabov, O. A.

N1 - The study was supported by the Russian Science Foundation grant No. 19-19-00695 , https: rscf.ru. en. project. 19-19-00695.

PY - 2024/5

Y1 - 2024/5

N2 - To date, in the public domain there is a lot of experimental data on adiabatic two-phase flow in microchannels of various geometries (round, rectangular, square). However, microchannels with high aspect ratio (slit microchannels) remain poorly understood. In this article, an adiabatic two-phase flow in a slit microchannel with a height of 12.5 µm and width of 10 mm (aspect ratio 1:800) has been experimentally investigated for the first time in the wide range of liquid and gas superficial velocities (from 0.0026 to 0.266 m/s for liquid and from 0.266 to 7.73 m/s for gas). The combination of photolithography, anisotropic etching and thermal anode bonding allow us to create flow cells with slit microchannel height of 12.5 µm and width of 10 mm. Channel height and characteristics of channel surfaces (roughness and contact angles) have been measured using scanning electron microscopy (SEM) stylus profilometer, atomic force microscopy (AFM) and sessile drop technique respectively. For the first time, the new flow pattern and flow patterns transitions have been investigated and flow pattern maps for several liquids with various physical properties have been constructed. One of these maps has been compared with a map of a slit microchannel with large height. It is shown that the flow pattern maps for liquids that completely wet the mixing section can be generalized in coordinates liquid Capillary number Cal and gas Weber number Weg, which indicates the negligible effect of liquid inertia forces on the flow pattern boundaries. It has been shown that with an increase of surface tension, the region of the Jet flow pattern expands. It has been established that Saffman-Taylor instability in the mixing section and along the channel, instability caused by transverse pressure gradient and surface wettability are pattern-determined factors.

AB - To date, in the public domain there is a lot of experimental data on adiabatic two-phase flow in microchannels of various geometries (round, rectangular, square). However, microchannels with high aspect ratio (slit microchannels) remain poorly understood. In this article, an adiabatic two-phase flow in a slit microchannel with a height of 12.5 µm and width of 10 mm (aspect ratio 1:800) has been experimentally investigated for the first time in the wide range of liquid and gas superficial velocities (from 0.0026 to 0.266 m/s for liquid and from 0.266 to 7.73 m/s for gas). The combination of photolithography, anisotropic etching and thermal anode bonding allow us to create flow cells with slit microchannel height of 12.5 µm and width of 10 mm. Channel height and characteristics of channel surfaces (roughness and contact angles) have been measured using scanning electron microscopy (SEM) stylus profilometer, atomic force microscopy (AFM) and sessile drop technique respectively. For the first time, the new flow pattern and flow patterns transitions have been investigated and flow pattern maps for several liquids with various physical properties have been constructed. One of these maps has been compared with a map of a slit microchannel with large height. It is shown that the flow pattern maps for liquids that completely wet the mixing section can be generalized in coordinates liquid Capillary number Cal and gas Weber number Weg, which indicates the negligible effect of liquid inertia forces on the flow pattern boundaries. It has been shown that with an increase of surface tension, the region of the Jet flow pattern expands. It has been established that Saffman-Taylor instability in the mixing section and along the channel, instability caused by transverse pressure gradient and surface wettability are pattern-determined factors.

KW - Flow patterns

KW - Flow patterns borders

KW - Liquid film

KW - Slit microchannel

KW - Two-phase flow

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85184033135&origin=inward&txGid=f2ad82b73562bbd9ec12848b4ea7857a

UR - https://www.mendeley.com/catalogue/677c0325-b7cc-3312-aac5-ee90052ad1be/

U2 - 10.1016/j.expthermflusci.2024.111153

DO - 10.1016/j.expthermflusci.2024.111153

M3 - Article

VL - 154

JO - Experimental Thermal and Fluid Science

JF - Experimental Thermal and Fluid Science

SN - 0894-1777

M1 - 111153

ER -