Research on Coanda Effect Appeared in Oil-Air Annular Flow through the Conical Diffuser

2014 ◽  
Vol 668-669 ◽  
pp. 331-335
Author(s):  
Qi Guo Sun ◽  
Ying Wang ◽  
Xiong Shi Wang
Keyword(s):  
Numerical Simulation ◽  
Liquid Phase ◽  
Pressure Drop ◽  
Annular Flow ◽  
Radial Pressure ◽  
Coanda Effect ◽  
Expansion Angle ◽  
Flow Through ◽  
Radial Pressure Gradient ◽  
Coandǎ Effect

Physical model and numerical simulation model for oil-air annular flow through conical diffusers are built by Fluent, and Coanda Effect, a commonly phenomenon, appeared in this kind of oil-air annular flow field is studied, especially influences of Coanda Effect on the attachment of the liquid phase of annular flow trended to the curved wall are analyzed in detail by changing expansion angles to calculate the radial pressure distribution and pressure drop, employed numerical simulation method, in this paper. The simulation results show that the expansion angle has a great influence on the attachment of liquid phase in annular flow to the curved wall, the radial pressure gradient is an important factor of the Coanda Effect which make the liquid phase of annular flow convey near the wall, and the radial pressure gradient will decrease but the pressure drop increase when the expansion angle becomes larger. These conclusions will provide useful reference in designing pipelines conveying the two-phase annular flow in oil-air lubrication system.

scholarly journals Application of Direct Numerical Simulation to Determine the Correlation Describing Friction Losses during the Transverse Flow of Fluid in Hexagonal Array Pin Bundles

Fluids ◽  
2022 ◽  
Vol 7 (1) ◽  
pp. 22
Author(s):  
Yury Shvetsov ◽  
Yury Khomyakov ◽  
Mikhail Bayaskhalanov ◽  
Regina Dichina
Keyword(s):  
Numerical Simulation ◽  
Reynolds Number ◽  
Pressure Drop ◽  
Liquid Metal ◽  
Direct Numerical Simulation ◽  
Incompressible Fluid ◽  
Reactor Core ◽  
Transverse Flow ◽  
Hexagonal Array ◽  
Flow Through

This paper presents the results of a numerical simulation to determine the hydraulic resistance for a transverse flow through the bundle of hexagonal rods. The calculations were carried out using the precision CFD code CONV-3D, intended for direct numerical simulation of the flow of an incompressible fluid (DNS-approximation) in the parts of fast reactors cooled by liquid metal. The obtained dependencies of the pressure drop and the coefficient of anisotropy of friction on the Reynolds number can be used in the thermal-hydraulic codes that require modeling of the flow in similar structures and, in particular, in the inter-wrapper space of the reactor core.

Coanda Effect on the Impact of Distribution Characteristics of Oil-Air Annular Flow

2014 ◽  
Vol 620 ◽  
pp. 166-170
Author(s):  
Qi Guo Sun ◽  
Dong Xu Chen ◽  
Xiong Shi Wang ◽  
Zheng Hui Zhou
Keyword(s):  
Pressure Gradient ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Annular Flow ◽  
Branch Pipe ◽  
Coanda Effect ◽  
Distribution Characteristics ◽  
Coandǎ Effect ◽  
The Impact

The T-junction model is simulated in Fluent by changing the curvature of branch pipe, and then the distribution characteristics of the annular flow was studied in T-junction distributor. The mass flow and pressure of the annular flow in this T-junction are studied, and the impact of Coanda Effect on the annular flow distribution characteristic is analyzed in oil-air two phases flow. The results show that, Coanda Effect affects the distribution of oil-air annular flow unevenly. The mass flow rate of air phase and the air velocity of outlet increase with decreasing the curvature, while the mass flow rate of liquid decrease with decreasing the curvature of the branch pipe connection; T-shaped junction inlet pressure is high, but the pressure gradient is small, the pressure gradient in the small curvature manifold is larger than that in the large curvature manifold.

scholarly journals PHENOMENOLOGICAL ANALYSIS OF A CONCEPTUAL WATERJET PROPULSOR BASED ON THE COANDA EFFECT

2019 ◽  
Vol 18 (1) ◽  
pp. 03
Author(s):  
R. L. Lemos ◽  
C. H. Marques ◽  
L. A. Rocha ◽  
L. A. Isoldi ◽  
E. D. dos Santos
Keyword(s):  
Physical Phenomenon ◽  
Transient State ◽  
Water Jet ◽  
Coanda Effect ◽  
Ansys Fluent ◽  
Marine Propulsion ◽  
Flow Through ◽  
Coandǎ Effect ◽  
Mechanical Devices ◽  
Volume Method

This work is part of a research project conceived at the Federal University of Rio Grande. The project aims to create and develop mechanical devices that use the Coanda effect to enhance their overall efficiency. The focus herein is analyzing the physical phenomenon occurring in a conceptual water-jet propulsor. In the proposed concept, a water-jet propulsor has its impeller replaced by injectors that produce the so-called Coanda effect, increasing thereby the mass flow rate. In order to simulate the flow through the propulsor, a numerical model was developed. In this model the time-averaged conservation equations of mass and momentum were solved numerically by the finite volume method, more precisely with the commercial package ANSYS FLUENT (version 14.0). For the closure of the constitutive equations, the k-ω URANS turbulence model was employed. The simulation was performed for a transient state with a timestep of ∆t = 1×10-3 s and a total physical time of t = 6.0 s. Static pressure fields, streamlines and speed profiles are used to analyze the equipment performance and the phenomenon occurrence. The results show that the Coanda Effect is able to generate thrust in a waterjet propulsion device without impeller. The study suggests that the employment of this principle has promising applicability in marine propulsion and deserves attention on future works.

scholarly journals Experiment and Numerical Simulation on Gas-Liquid Annular Flow through a Cone Sensor

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2923 ◽  
Author(s):  
Denghui He ◽  
Senlin Chen ◽  
Bofeng Bai
Keyword(s):  
Numerical Simulation ◽  
Annular Flow ◽  
Gas Flow ◽  
Low Pressure ◽  
Pressure Recovery ◽  
Liquid Distribution ◽  
Wet Gas ◽  
Sensor Structure ◽  
Gas Measurement ◽  
Flow Through

The cone meter has been paid increasing attention in wet gas measurement, due to its distinct advantages. However, the cone sensor, which is an essential primary element of the cone meter, plays a role in the measurement of wet gas flow that is important, but not fully understood. In this article, we investigate the gas-liquid annular flow through a cone sensor by experiment and numerical simulation. Emphasis is put on the influences of pressure recovery characteristics and flow structure, and how they are affected by the cone sensor. The results show that the vortex length is shortened in gas-liquid annular flow, compared with that in single-phase gas flow. The pressure recovery length is closely related with the vortex length, and shorter vortex length leads to shorter pressure recovery length. The gas-liquid distribution suggests that flow around the apex of back-cone is very stable, little liquid is entrained into the vortex, and no liquid appears around the low pressure tapping, which makes a more stable pressure at the apex of cone sensor feasible. This finding highlights the importance of obtaining the low pressure from the back-cone apex, which should be recommended in the multiphase flow measurement. Our results may help to guide the optimization of the cone sensor structure in the wet gas measurement.

scholarly journals Experiment and numerical simulation of a valveless piezoelectric micropump applying Coanda effect

2016 ◽  
Vol 17 (2) ◽  
pp. 204 ◽  
Author(s):  
Xiuhua He ◽  
Xitong Zhang ◽  
Song Yang ◽  
Jiawei Zhu ◽  
Jie Yan
Keyword(s):  
Numerical Simulation ◽  
Coanda Effect ◽  
Coandǎ Effect

Numerical Simulation on Unstable Phenomenon of Coanda Effect

2002 ◽  
Vol 2002.3 (0) ◽  
pp. 249-250
Author(s):  
Masato SEINO ◽  
Ichiro KANO ◽  
Miki YAGITA
Keyword(s):  
Numerical Simulation ◽  
Coanda Effect ◽  
Coandǎ Effect
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