Shell balance

About: Shell balance is a research topic. Over the lifetime, 154 publications have been published within this topic receiving 3691 citations.

The Influence of Actuator Parameters on Fluid Jetting Dispensing

Abstract: The actuator is an important component of the fluid jet-dispenser,and has an important influence on the fluid volume and velocity of the fluid jetted from the jet-dispenserThe calculation formula of cumulative fluid volume and its equivalent velocity based on fluid kinetic energy are deduced through central velocity at the nozzle outlet from the numerical simulation result,then cumulative fluid volume and equivalent velocity are computed under the condition of different actuator parameters by MATLAB programThis research supplies some foundation for the design and operation adjustment of the actuatorThe results show a good changeing characteristic of the cumulative fluid volume and equivalent velocity,the stroke of the ball-needle compared with its acceleration has less influence on the jetting fluid dispensing

Dynamics and stability of a fluid filled cylinder rolling on an inclined plane

Abstract: The dynamics and stability of a fluid-filled hollow cylindrical shell rolling on an inclined plane are analyzed. We study the motion in two dimensions by analyzing the interaction between the fluid and the cylindrical shell. An analytical solution is presented to describe the unsteady fluid velocity field as well as the cylindrical shell motion. From this solution, we show that the terminal state is associated with a constant acceleration. We also show that this state is independent of the liquid viscosity and only depends on the ratio of the shell mass to the fluid mass. We then analyze the stability of this unsteady flow field by employing a quasi-steady frozen-time framework. The stability of the instantaneous flow field is studied and transition from a stable to an unstable state is characterized by the noting the time when the eigenvalue crosses the imaginary axis. It is observed that the flow becomes unstable due to long wavelength axial waves. We find a critical Reynolds number ($\approx 5.6$) based on the shell angular velocity at neutral stability with the corresponding Taylor number being $\approx 125.4$. Remarkably, we find that this critical value is independent of the dimensionless groups governing the problem. We show that this value of the critical Reynolds number can be explained from a comparison of time scales of motion and momentum diffusion, which predicts a value near $2 \pi$.

Impact of an elastic spherical shell on a thin fluid layer

Abstract: The axisymmetric problem of the impact of a spherical shell on a thin layer of an ideal incompressible fluid is considered. The strains of the spherical shell are described by means of the normal mode method, a decomposition of the fluid flow zone onto subzones proposed in [1] being used for the hydrodynamic analysis and determination of the radius of the wetted surface. The connected problem of hydroelasticity is reduced to an evolutionary system of differential equations and calculations of the features of impact are carried for various parameters of the problem. It is shown that vibrations corresponding to the higher modes develop in the lower part of the shell during the impact on the fluid surface. This is in agreement with experiments and proves the inconsistency of the models in which a few number of modes are taken into account. The thinner is the fluid layer, the higher are the hydrodynamic loads and the amplitude of elastic vibrations of the shell during the impact.

Forced oscillations of shells of revolution in a viscous fluid flow

Abstract: The influence of mechanical properties of a large-sized shell on its forced oscillations in a flow of a viscous fluid is considered. As is known [1], the flow past a shell can be controlled by generating a wave that runs over the shell surface. Hydrodynamic calculations performed for only transverse running waves [2–6] show the potential possibility of significantly decreasing the drag, but conditions under which these running waves can be maintained in a shell of finite length had not been studied until now. The present paper considers the laws that govern a running wave generated in the front part of a shell of revolution occurring in a flow of a viscous fluid.

Effect of Gravity on the Hydrodynamics in an Unbaffled Stirred Vessel

Abstract: The hydrodynamics in an unbaffled stirred vessel were simulated in order to highlight the effect of gravity on pressure and velocity distributions. Two fluids with different viscosity were studied for the laminar and turbulent flow regimes, respectively. The simulation results were compared with experimental data from the literature. Results indicate that for the higher-viscosity fluid, gravity only affects static pressure and that the effects of gravity on velocity and dynamic pressure are negligible. For the lower-viscosity fluid, however, gravity imposes a pronounced impact on static pressure, dynamic pressure, velocity, and turbulent kinetic energy. These findings indicate that careful consideration is necessary for the role that gravity plays in the study of free-surface hydrodynamics in unbaffled stirred vessels.