THE INFLUENCE OF GRAVITY AND CONTACT ANGLE ON THE LIQUID FLOW IN THE SURFACE TENSION TANK

The flow behavior inside the vane surface tension tank is studied by using CFD-VOF method. Gravitational acceleration and contact angle are taken into consideration as control parameters. It is shown that when the contact angle is 10° and the gravitational acceleration is less than 10^-2g₀, the fluid reaches the top of the tank along the outer vanes. Moreover, the flow along the outer vanes is little influenced by the decrease of the gravitational acceleration when the gravitational acceleration is less than 10^-3g₀. The fluid velocity near the outer vanes decays gradually during the flow process, and the initial velocity depends on gravitational acceleration, the less gravitational acceleration, the larger initial velocity. Furthermore, the height of the flow climbing is impacted significantly by the contact angle. As the contact angle decreases the time of the fluid climbing to the top of the tank increased, and when the contact angle is greater than 45°, the fluid near the outer vanes cannot reach the top of tank. Ultimately, the relationship between the length of the climbing flow (L(t)) with the contact angle (θ) is also analyzed. It is observed that the increase of contact angle leads to the decreases of slope of the L(t) and the initial velocity of the fluid near the vanes.