Mass Transfer and Friction in Near-Wall Film Flows in Conditions of High-Velocity Co-Current Gas Flow

Abstract

We present the experimental research on the interaction of co-current gas flow with near-wall liquid film for gas velocities up to 300 m/s. Local parameters of near-wall liquid film are measured by using capacitytype probes. It is shown that co-current gas flow has strong influence on near-wall liquid film, leading to intensive wave formation, detachment of droplets from the film surface and their entrainment by the gas flow. Thus it is shown that the relative amount of liquid carried away by co-current gas flow is well characterized by Weber number of gas flow. A model for the motion of a film with co-current flow, connecting a thickness and velocity of the film with value of shearing stress at gas-liquid boundary, is suggested. It is shown that intensive wave formation leads to essential increase of the interphase friction value.

Experimental Study of the International Space Station Contamination by Its Orientation Thrusters Jets

“…Our earlier studies Prikhodko et al 2009) showed that there are some distinguishing characteristics of liquid film behavior inside a cylindrical channel and on its exit edge. They were obtained for a case of near-wall liquid film ejection with cocurrent gas flow from a cylindrical channel of 5 mm diameter into vacuum.…”

Interphase interaction of near-wall liquid film with co-current gas flow inside a nozzle

“…Measurements of local parameters of a near-wall liquid film (film thickness and film velocity) in the present study were carried out with the help of capacity-type probes [7]. Film thickness and velocity were measured near the exit edge of the supersonic nozzle (geometrical Mach number M = 3) with 10 mm throat diameter, 20 mm exit diameter and 20 mm nozzle length (Fig.…”

Near-wall liquid film outflow of water-ethanol mixture from cylindrical channel into vacuum

“…Under ejection into atmosphere the revealed effect is absent, and the ordinary gas-droplet flow takes place behind the exit cross-section of the channel. Another important feature of wall liquid film behavior inside the channel noted in [5] is presence of high-velocity co-current gas flow. Gas velocity under expansion from the cylindrical channel into vacuum reaches sonic velocity at the exit cross-section.…”

“…According to current understanding [6] detachment of droplets from the film surface and their carrying away by co-current gas flow takes place at Weber numbers We > 2. Experimental studies [5] have shown that amount of liquid carried away by gas flow can reach significant values (tens of percent of the liquid initial flow rate). Note that only ethanol was used as working liquid in studies [4,5].…”

“…Experimental studies [5] have shown that amount of liquid carried away by gas flow can reach significant values (tens of percent of the liquid initial flow rate). Note that only ethanol was used as working liquid in studies [4,5]. Current paper is devoted to experimental study of water-ethanol mixtures (with concentration from 0 to 100%) ejection with co-current gas flow from cylindrical channel into rarefied space.…”