Experiments and Numerical Simulations of water spray by hollow cone nozzle

The liquid jet breakup is a ubiquitous phenomenon in nature and a classic problem in hydrodynamics. The understanding of the jet breakup mechanism of hot liquids is still a challenge for researchers. The objective of this work was to understand and control the hot water spray jet breakup mechanism at moderate pumping pressures and elevated temperature. For this purpose, the visual and comparative studies were conducted on hollow cone water spray patterns generated by three hollow cone spray nozzles which were installed in an in-house built intermittently forced liquid spraying system. Using a high speed camera, the jet breakup dynamics were visualized as a function of system input parameters. The analysis of the grabbed images confirmed the strong influence of these processing parameters on spray characteristics. It was also predicted that heated liquids generate the dispersed spray patterns and the induction of thermal energy into the system enhances the jet disintegration ability. The spray cone width and angle were not varied significantly whereas the Weber and Reynolds numbers along with other spray parameters showed an appreciable response to the load pressure and water heating temperature at early stages of water injection.

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Mixing of hollow-cone water spray in a confined high-temperature gas crossflow

Computers & Fluids ◽

10.1016/j.compfluid.2017.06.007 ◽

2017 ◽

Vol 154 ◽

pp. 216-223 ◽

Cited By ~ 1

Author(s):

Wenjie Wang ◽

Haibin Zhang ◽

Zhongchuang Zhao ◽

Qinghai Zheng ◽

Bofeng Bai

Keyword(s):

High Temperature ◽

Water Spray ◽

Hollow Cone ◽

High Temperature Gas

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Numerical Simulations for Super Large-Scale Natural Draft Cooling Tower With an Optimized Non-Uniform Water Distribution

Volume 8: Computational Fluid Dynamics (CFD) and Coupled Codes; Nuclear Education, Public Acceptance and Related Issues ◽

10.1115/icone25-67057 ◽

2017 ◽

Author(s):

J. Y. Li ◽

H. Wang ◽

W. Sheng

Keyword(s):

Numerical Simulations ◽

Water Distribution ◽

Large Scale ◽

Cooling Tower ◽

Water Pressure ◽

Water Spray ◽

Natural Draft ◽

Precise Data ◽

Spray Density ◽

Autumn And Winter

The great spray area of a Super Large-Scale Natural Draft Cooling Tower (SLNDWCT) makes it difficult to achieve an uniform wind field, and non-uniform water spray distributions are adopted in engineering. In this paper, to improve the cooling performance, optimized non-uniform water spray distributions are designed by utilizing network hydraulic calculations and numerical simulations. In the network calculations, the node-formula is applied to figure out the water pressure and flow rate of each spray nozzle, providing more precise data in simulations for the heat and mass transfer. Simulations for operating in summer, Spring/Autumn and winter seasons, which are different in water spray density, have been presented. In the operating in summer, the spray zone is divided into two regions (inner and outer regions), and by adjusting the water spray density and areas of the two regions, an improved water distribution is achieved.

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Pressure Jet Spray in Air Stream

Volume 1B: General ◽

10.1115/70-gt-101 ◽

1970 ◽

Cited By ~ 4

Author(s):

R. Mellor ◽

N. A. Chigier ◽

J. M. Beér

Keyword(s):

Size Range ◽

Equation Of Motion ◽

State Equation ◽

Water Spray ◽

Hollow Cone ◽

Initial Droplet ◽

Steady State Equation ◽

Air Stream ◽

Droplet Behavior ◽

Solid Spheres

A study has been made of droplet trajectories in a hollow cone pressure-jet water spray operating in a uniform axial airflow of 13.9 m/s. Use of a double spark light source enabled measurements of drop velocities, sizes and angles of trajectories to be made on droplets in the size range 20 to 250 microns with velocities up to 37 m/s. Entrainment into the spray of the surrounding airflow was found to be negligible in a wind tunnel and it was found possible to predict the trajectories of individual drops on the basis of the steady-state equation of motion for single solid spheres in an infinite quiescent atmosphere. Average droplet behavior could not be predicted because of the wide variation in initial droplet conditions.

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Electronic Cone Illumination with the Conventional Transmission Electron Microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100077980 ◽

1977 ◽

Vol 35 ◽

pp. 72-73

Author(s):

William Krakow

Keyword(s):

Electronic Device ◽

Chromatic Aberration ◽

Objective Lens ◽

Hollow Cone ◽

Transmission Electron ◽

Lissajous Figures ◽

High Resolution Images ◽

Imaging Mode ◽

Diffraction Patterns ◽

Transmission Microscope

An electronic device has been constructed which manipulates the primary beam in the conventional transmission microscope to illuminate a specimen under a variety of virtual condenser aperture conditions. The device uses the existing tilt coils of the microscope, and modulates the D.C. signals to both x and y tilt directions simultaneously with various waveforms to produce Lissajous figures in the back-focal plane of the objective lens. Electron diffraction patterns can be recorded which reflect the manner in which the direct beam is tilted during exposure of a micrograph. The device has been utilized mainly for the hollow cone imaging mode where the device provides a microscope transfer function without zeros in all spatial directions and has produced high resolution images which are also free from the effect of chromatic aberration. A standard second condenser aperture is employed and the width of the cone annulus is readily controlled by defocusing the second condenser lens.

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Experiments in Bright-Field Imaging with Hollow-Cone Illumination

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100097703 ◽

1981 ◽

Vol 39 ◽

pp. 226-227

Author(s):

W. Kunath ◽

K. Weiss ◽

E. Zeitler

Keyword(s):

Signal To Noise Ratio ◽

Carbon Support ◽

Electronic System ◽

Optic Axis ◽

Hollow Cone ◽

Signal To Noise ◽

Bright Field ◽

Noise Ratio ◽

Single Field ◽

Field Imaging

Bright-field images taken with axial illumination show spurious high contrast patterns which obscure details smaller than 15 ° Hollow-cone illumination (HCI), however, reduces this disturbing granulation by statistical superposition and thus improves the signal-to-noise ratio. In this presentation we report on experiments aimed at selecting the proper amount of tilt and defocus for improvement of the signal-to-noise ratio by means of direct observation of the electron images on a TV monitor.Hollow-cone illumination is implemented in our microscope (single field condenser objective, Cs = .5 mm) by an electronic system which rotates the tilted beam about the optic axis. At low rates of revolution (one turn per second or so) a circular motion of the usual granulation in the image of a carbon support film can be observed on the TV monitor. The size of the granular structures and the radius of their orbits depend on both the conical tilt and defocus.

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