scholarly journals Cavitation in atomizer channels of water-mist Fi-Fi systems

2021 ◽  
Vol 1 (395) ◽  
pp. 109-118
Author(s):  
S. Boroday ◽  
Keyword(s):  
Fluid Dynamics ◽  
Flow Rate ◽  
Water Mist ◽  
High Flow ◽  
Engineering Analysis ◽  
Ansys Cfx ◽  
Modern Methods ◽  
Computer Based ◽  
Computational Fluid Dynamics Cfd ◽  
Swirl Atomizer

Object and purpose of research. This paper discusses insufficient flow rate in a standard swirl atomizer of ma-rine water-mist Fi-Fi systems. The purpose of this study was to find the reasons for this insufficient flow rate and the ways to improve it. Materials and methods. This research was a computer-based simulation (in commercial ANSYS CFX package for engineering analysis) based on modern methods of computational fluid dynamics (CFD). Main results. An upgraded swirler for high-flow atomizer preventing cavitation in its inner channels. Conclusion. These results make it possible to design atomizers and sprinklers of marine water-mist Fi-Fi systems with cavitation-free swirler channels.

A CFD Analysis for the Advanced Accumulator

2014 ◽  
Author(s):  
Donghua Lu ◽  
Kuo Wang ◽  
Qianhua Su ◽  
Jun Xing
Keyword(s):  
Fluid Dynamics ◽  
Flow Control ◽  
Flow Pattern ◽  
Flow Rate ◽  
Vortex Chamber ◽  
Flow Chamber ◽  
High Flow ◽  
Low Flow ◽  
Cfd Analysis ◽  
Computational Fluid Dynamics Cfd

A new design for the flow control component of an advanced accumulator (ACC) was introduced and numerically investigated in the paper. The flow control component can produce high flow rate and low flow rate at the different stages during the safety injection. The FLUENT computational fluid dynamics (CFD) was used in the simulation of the flow pattern in the flow chamber and the outlet. The flow pattern and pressure gradient in the vortex chamber were investigated. The results show the design can realize the high flow and low flow in this design.

scholarly journals Effect of hydraulic and geometric factors upon leakage flow rate in pressurized pipes

RBRH ◽  
2021 ◽  
Vol 26 ◽  
Author(s):  
Mayara Francisca da Silva ◽  
Fábio Veríssimo Gonçalves ◽  
Johannes Gérson Janzen
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Rate ◽  
Leakage Flow ◽  
Cfd Simulations ◽  
Mean Velocity ◽  
Leakage Flow Rate ◽  
Geometric Factors ◽  
Leakage Area ◽  
Computational Fluid Dynamics Cfd

ABSTRACT Computational Fluid Dynamics (CFD) simulations of a leakage in a pressurized pipe were undertaken to determine the empirical effects of hydraulic and geometric factors on the leakage flow rate. The results showed that pressure, leakage area and leakage form, influenced the leakage flow rate significantly, while pipe thickness and mean velocity did not influence the leakage flow rate. With relation to the interactions, the effect of pressure upon leakage flow rate depends on leakage area, being stronger for great leakage areas; the effects of leakage area and pressure on leakage flow rate is more pronounced for longitudinal leakages than for circular leakages. Finally, our results suggest that the equations that predict leakage flow rate in pressurized pipes may need a revision.

scholarly journals Modelling of working processes of non-contact oil free vacuum pumps by computational fluid dynamics (CFD) methods

2021 ◽  
Vol 2059 (1) ◽  
pp. 012003
Author(s):  
A Burmistrov ◽  
A Raykov ◽  
S Salikeev ◽  
E Kapustin
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Mathematical Models ◽  
Cfd Models ◽  
Ansys Cfx ◽  
Sst Turbulence Model ◽  
Computational Fluid Dynamics Cfd ◽  
Dynamic Meshing ◽  
Comparison With Experimental Data

Abstract Numerical mathematical models of non-contact oil free scroll, Roots and screw vacuum pumps are developed. Modelling was carried out with the help of software CFD ANSYS-CFX and program TwinMesh for dynamic meshing. Pumping characteristics of non-contact pumps in viscous flow with the help of SST-turbulence model were calculated for varying rotors profiles, clearances, and rotating speeds. Comparison with experimental data verified adequacy of developed CFD models.

On the Discretization of the Power-Law Hemolysis Model

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Mohammad M. Faghih ◽  
Ahmed Islam ◽  
M. Keith Sharp
Keyword(s):  
Fluid Dynamics ◽  
Power Law ◽  
Velocity Fields ◽  
Radial Expansion ◽  
Complex Flows ◽  
Cfd Simulations ◽  
Large Exponent ◽  
Computer Based ◽  
Computational Fluid Dynamics Cfd ◽  
Simple Flows

Abstract Flow-induced hemolysis remains a concern for blood-contacting devices, and computer-based prediction of hemolysis could facilitate faster and more economical refinement of such devices. While evaluation of convergence of velocity fields obtained by computational fluid dynamics (CFD) simulations has become conventional, convergence of hemolysis calculations is also essential. In this paper, convergence of the power-law hemolysis model is compared for simple flows, including pathlines with exponentially increasing and decreasing stress, in gradually expanding and contracting Couette flows, in a sudden radial expansion and in the Food and Drug Administration (FDA) channel. In the exponential cases, convergence along a pathline required from one to tens of thousands of timesteps, depending on the exponent. Greater timesteps were required for rapidly increasing (large exponent) stress and for rapidly decreasing (small exponent) stress. Example pathlines in the Couette flows could be fit with exponential curves, and convergence behavior followed the trends identified from the exponential cases. More complex flows, such as in the radial expansion and the FDA channel, increase the likelihood of encountering problematic pathlines. For the exponential cases, comparison of converged hemolysis values with analytical solutions demonstrated that the error of the converged solution may exceed 10% for both rapidly decreasing and rapidly increasing stress.

Study of Gas Shortcut Flow Rate in Cyclone with Different Inlet Section Angles Using Response Surface Methodology

2009 ◽  
Vol 7 (1) ◽  
Author(s):  
Fuping Qian ◽  
Xingwei Huang ◽  
Mingyao Zhang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Response Surface Methodology ◽  
Response Surface ◽  
Flow Rate ◽  
Numerical Solutions ◽  
Inlet Section ◽  
Statistical Software ◽  
Vortex Finder ◽  
Computational Fluid Dynamics Cfd

Numerical simulations of cyclones with various vortex finder dimensions and inlet section angles were performed to study the gas shortcut flow rate. The numerical solutions were carried out using commercial computational fluid dynamics (CFD) code Fluent 6.1. A prediction model of the gas shortcut flow rate was obtained based on response surface methodology by means of the statistical software program (Minitab V14). The results show that the length of the vortex finder insertion, the vortex finder diameter and the inlet section angle play an important role in influencing the gas shortcut flow rate. The gas shortcut flow rate decreases when increasing the inlet section angle, and increases when increasing the vortex finder diameter and decreasing the length of the vortex finder insertion. Compared with the effect of the length of the vortex finder insertion on the shortcut flow rate, the effect of the vortex finder diameter on the gas shortcut flow rate seems more pronounced. The effect of the vortex finder dimension on the gas shortcut flow rate is changed with the different inlet section angles, i.e., the effects of the vortex finder dimension of the conventional cyclone (the inlet section angle is 0º) on the gas shortcut flow rate is stronger than the cyclone with 30º and 45º inlet section angles.

Computational Study of Single-Sided Ventilation Through a 3-Dimensional Room With Rounded Edges

2013 ◽  
Author(s):  
A. Idris ◽  
B. P. Huynh
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Speed ◽  
Flow Pattern ◽  
Flow Rate ◽  
Software Package ◽  
Computational Study ◽  
Ventilation Rate ◽  
3 Dimensional ◽  
Computational Fluid Dynamics Cfd

A commercial Computational Fluid Dynamics (CFD) software package is used to investigate numerically a 3-dimensional rectangular-box room with rounded edges. The room has all its window openings located on one wall only. The standard K-ε turbulence model is used. Air’s flow rate and flow pattern are considered in terms of wind speed and the openings’ characteristics, such as their number, location, size and shape. Especially, comparison with ventilation rate corresponding to when the room edges are sharp is made; and thereby the effects of the edges being rounded are examined.

Transient Analysis of a Spring-Loaded Pressure Safety Valve Using Computational Fluid Dynamics (CFD)

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Xue Guan Song ◽  
Lin Wang ◽  
Young Chul Park
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Safety Valve ◽  
Three Dimensional ◽  
Pressure Vessels ◽  
Moving Mesh ◽  
Cfd Model ◽  
Ansys Cfx ◽  
Computational Fluid Dynamics Cfd ◽  
Mesh Technique

A spring-loaded pressure safety valve (PSV) is a key device used to protect pressure vessels and systems. This paper developed a three-dimensional computational fluid dynamics (CFD) model in combination with a dynamics equation to study the fluid characteristics and dynamic behavior of a spring-loaded PSV. The CFD model, which includes unsteady analysis and a moving mesh technique, was developed to predict the flow field through the valve and calculate the flow force acting on the disk versus time. To overcome the limitation that the moving mesh technique in the commercial software program ANSYS CFX (Version 11.0, ANSYS, Inc., USA) cannot handle complex configurations in most applications, some novel techniques of mesh generation and modeling were used to ensure that the valve disk can move upward and downward successfully without negative mesh error. Subsequently, several constant inlet pressure loads were applied to the developed model. Response parameters, including the displacement of the disk, mass flow through the valve, and fluid force applied on the disk, were obtained and compared with the study of the behavior of the PSV under different overpressure conditions. In addition, the modeling approach could be useful for valve designers attempting to optimize spring-loaded PSVs.

scholarly journals COMPARISON OF AIR DISTRIBUTION SYSTEMS IN ICE RINK ARENA VENTILATION

2013 ◽  
Vol 5 (4) ◽  
pp. 429-434 ◽  
Author(s):  
Agnieszka Stobiecka ◽  
Barbara Lipska ◽  
Piotr Koper
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Distribution Systems ◽  
Numerical Calculations ◽  
Air Distribution ◽  
Humid Air ◽  
Ice Surface ◽  
Ansys Cfx ◽  
Computational Fluid Dynamics Cfd

The paper presents the requirements and functions of ventilation in ice rink arenas and discusses difficulties and problems of ventilation in such objects. Particular attention has been paid to two types of inside used air distribution systems – traditional-integrated and modern-separated where the functions of tribune ventilation and dehumidification of the air over the ice surface were separated. The flow of humid air and heat in the designed hall was modelled numerically using the ANSYS CFX code based on computational fluid dynamics (CFD) technique. Air distribution systems in the ice rink arena were compared based on the results of numerical calculations.

Numerical Simulation on the Parallel Combined Nozzles of Mini/Micro Gas Flow Standard Device

2012 ◽  
Vol 472-475 ◽  
pp. 2000-2003
Author(s):  
Jin Long Meng ◽  
Zhao Qin Yin
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Flow Rate ◽  
Gas Flow ◽  
Flow Characteristics ◽  
Micro Gas Flow ◽  
Actual Flow Rate ◽  
Actual Flow ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method

The flow characteristics in mini/micro sonic nozzles have been studied in this paper using the computational fluid dynamics (CFD) method. The result shows that the flow rate of the parallel combined nozzles is not equal to but smaller than that of the sum of the nozzles. The reason is the each effect of the air after nozzles, which changes the flow field parameters .The more number of the parallel combined nozzles, the bigger error exits between actual flow rate and that of the sum of the nozzles. The result is consistent to the experiment. The study also shows the smaller of the nozzle’s diameter, the bigger error exits.

Effects of Impeller Squealer Tip on Centrifugal Compressor Performance

2016 ◽  
Author(s):  
Riccardo Da Soghe ◽  
Cosimo Bianchini ◽  
Lorenzo Toni ◽  
Dante Tommaso Rubino
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Flow ◽  
Tip Clearance ◽  
Flow Coefficient ◽  
Performance Improvements ◽  
Positive Effects ◽  
Computational Fluid Dynamics Cfd ◽  
Compressor Performance ◽  
Load Conditions

This paper summarizes the main results sorted out from a Design of Experiment (DoE) based on a validated Computational Fluid Dynamics (CFD). Several tip recessed geometries applied to an unshrouded impeller were considered in conjunction with two tip clearance levels. The computations show that recessed tip geometries have positive effects when considering high flow coefficient values while in part-load conditions the gain is reduced. Starting from the results obtained when studying tip cavities, a single rim tip squealer geometry was then analysed: the proposed geometry leads to performance improvements for all the tested conditions considered in this work.

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