Investigation of the Linear Stability Problem of Electrified Jets, Inviscid Analysis

Download
2012-09-01
The instability characteristics of a liquid jet discharging from a nozzle into a stagnant gas are investigated using the linear stability theory. Starting with the equations of motion for incompressible, inviscid, axisymmetric flows in cylindrical coordinates, a dispersion relation is obtained, where the amplification factor of the disturbance is related to its wave number. The parameters of the problem are the laminar velocity profile shape parameter, surface tension, fluid densities, and electrical charge of the liquid jet. The dispersion relation is numerically solved as a function of the wave number. The growth of instabilities occurs in two modes, the Rayleigh and atomization modes. For rWe < 1 (where We represents the Weber number and r represents the gas-to-liquid density ratio) corresponds to a Rayleigh or long wave instability, where atomization does not occur. On the contrary, for rWe >> 1 the waves at the liquid-gas interface are shorter and when they reach a threshold amplitude the jet breaks down or atomizes. The surface tension stabilizes the flow in the atomization regime, while the density stratification and electric charges destabilize it. Additionally, a fully developed flow is more stable compared to an underdeveloped one. For the Rayleigh regime, both the surface tension and electric charges destabilize the flow. [DOI: 10.1115/1.4007157]
JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME

Suggestions

ANALYTICAL EXPRESSIONS FOR LIQUID-COLUMN VELOCITIES IN PIPELINES WITH ENTRAPPED GAS
Tijsseling, Arris S.; Hou, Qingzhi; Bozkuş, Zafer (2015-01-01)
High pressures and high temperatures may arise in pipelines when a liquid column is suddenly accelerated into a gas pocket trapped at a closed end. A mass oscillation occurs that is described by nonlinear equations for both liquid and gas. Analytical expressions are derived for the uniform velocity of the liquid column, from which pressures and gas temperatures follow. The obtained results are validated against theoretical and experimental results published by fellow researchers.
Investigation of air bubble motion in counter-current water flow conditions
Bezdegümeli, Uğur; Yeşin, Ahmet Orhan; Department of Mechanical Engineering (2003)
In this thesis study, air bubble motion in counter-current water flow conditions in a vertical pipe is investigated experimentally. For this purpose, a test set-up was designed and constructed. Images of motions of single bubbles, having different diameters in the range of 3.0-4.8 mm, generated by specially designed bubble injectors were recorded by using a monochrome camera, an image capture card and a PC. Recorded video images were processed to obtain the necessary data for the The purpose of the study is...
Development of an iterative method for liquid-propellant combustion chamber instability analysis
Cengiz, Kenan; Özyörük, Yusuf; Department of Aerospace Engineering (2010)
Controlling unsteady combustion induced gas flow fluctuations and the resultant motor vibrations is a very significant step in rocket motor design. It occurs when the unsteady heat release due to combustion happens to feed the acoustic oscillations of the closed duct forming a feed-back system. The resultant vibrations concerned may even lead to total failure of the rocket system unless analysed and tested thoroughly. This thesis aims developing a linear numerical analysis method for the growth rate of inst...
Investigation of interaction between pressure relief valve and turbines during a transient flow in hydropower plant
Çetintaş, Mehmet Ali; Bozkuş, Zafer; Çelebioğlu, Kutay; Department of Civil Engineering (2022-2)
The main goal of the present study is to investigate the effect of pressure relief valve (PRV) on the hydraulic transients generated by multiple turbine operations. To achieve this goal, a numerical model of KEPEZ-I Hydropower plant is constructed in the Bentley HAMMER software, which employs the Method of Characteristics (MoC) for computations. The MoC has been proven worldwide as a versatile and accurate tool for solving non-linear, hyperbolic, partial differential equations in space-time domain for hydra...
MODELING OF TWO-DIMENSIONAL SOLIDIFICATION OF A FINITE CYLINDER
ODABAŞI, Gülnihal; Dursunkaya, Zafer (2016-01-01)
Two-dimensional solidification problem of a finite cylinder, in which the liquid phase is initially at the fusion temperature, is solved by using a front fixing approach. The external surfaces of the cylinder are subjected to a temporally or spatially varying temperature below freezing. The method employed is based on one used for the solution of a solidification problem in Cartesian domain. A coordinate transformation is applied in both radial and axial directions to obtain a square computational domain. T...
Citation Formats
S. Özgen and O. Uzol, “Investigation of the Linear Stability Problem of Electrified Jets, Inviscid Analysis,” JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME, pp. 0–0, 2012, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/40392.