Dynamics of a Vapour Bubble inside a Vertical Rigid Cylinder

In this Paper dynamics of a vapour bubble generated due to a local energy input inside a vertical rigid cylinder and in the absence of buoyancy forces is investigated. Different ratios of the rigid cylinder to the maximum radius of the bubble are considered. The Boundary Integral Equation Method is employed for numerical simulation of the problem. Results show that during the collapse phase of the bubble inside a vertical rigid cylinder, two liquid micro jets are developed on the top and bottom sides of the vapour bubble and are directed inward. Results also show that existence of a deposit rib inside the vertical rigid cylinder slightly increases the life time of the bubble. It is found that by increasing the ratio of the cylinder diameter to the maximum radius of the bubble, the rate of the growth and collapse phases of the bubble increases and the life time of the bubble decreases

Dynamics of a vapour bubble near a thin elastic plate

Numerical and experimental results show that during the collapse phase of a vapor bubble near a rigid boundary, in the absence of strong buoyancy forces, a liquid micro jet is developed on the side of the bubble far from the rigid surface and directed towards it. Numerical and experimental results also show that, in the case of a bubble near a free surface, during the collapse phase of the bubble and in the absence of strong buoyancy forces, the vapor bubble is repelled by the free surface. In this case a liquid micro jet is developed on the closest side of the bubble to the free surface and is directed away from it. The dynamic behavior of a vapor bubble near a free surface leads to the idea that a vapor bubble during its growth and collapse phases near a deformable diaphragm may have a behavior similar to its behavior near a free surface. In this paper dynamics of a vapor bubble during its growth and collapse phases near a thin elastic plate is investigated. It has been shown that the growth and collapse of a vapor bubble generated due to a high local energy input causes considerable deformation on the nearby thin elastic plate. Different thin elastic plates with different thicknesses and different flexural rigidities are assumed and the dynamic behavior of a vapor bubble near each of these plates is investigated. Results show that during the growth and collapse of a vapor bubble near a thin elastic plate with a proper thickness and flexural rigidity, in the absence of strong buoyancy forces, a liquid micro jet may develop on the closest side of the bubble to the thin elastic plate and directed away from it.http://deepblue.lib.umich.edu/bitstream/2027.42/84307/1/CAV2009-final132.pd

Numerical Study on the Effect of an Annulus Injector on the Hydrodynamic Behavior of a Spray

In the internal combustion engines geometry of the injector orifice has significant effect on the improving of the fuel spray characteristics. In the present paper, effect of a conical annulus injector with three different aspect ratios and three different divergence angles of the annulus orifice on the hydrodynamic behavior of a fuel spray have been investigated numerically. The conical annulus injector aspect ratio is the ratio of the height of the annulus cone to the diameter of its circular base. The geometry of the annulus conical injectors inspires this idea that this type of injectors could inject possible large amount of liquid fuel into a combustion chamber symmetrically and homogeneously. The CFD software AVL Fire has been employed for numerical simulation of diesel fuel spray evolution. Numerical results show that the annulus conical injectors inject liquid fuel with an approximately homogenous distribution of droplets in the combustion chamber in comparison with the conventional injectors. In this kind of injector, fuel has been uniformly distributed in the cylinder. Numerical results also show that the annulus injectors significantly increase the cone angle of the liquid fuel spray and decrease its penetration length

Numerical investigation on the pulsating bubble dynamics in a narrow cylinder with a compliant coating

10.1088/0169-5983/46/1/015513Fluid Dynamics Research461-FDRS

Numerical analysis of a cavitation bubble in the vicinity of an elastic membrane

10.1088/0169-5983/45/5/055503Fluid Dynamics Research455-FDRS