scholarly journals Research on Duct Flow Field Optimisation of a Robot Vacuum Cleaner

10.5772/50903 ◽  
2011 ◽  
Vol 8 (5) ◽  
pp. 65 ◽  
Author(s):  
Xiao-bo Lai ◽  
Hai-shun Wang ◽  
Hua-shan Liu
Keyword(s):  
Pressure Drop ◽  
Flow Field ◽  
Velocity Vector ◽  
Fluid Model ◽  
Three Dimensional ◽  
Theoretical Modelling ◽  
Duct Flow ◽  
Vacuum Cleaner ◽  
Arbitrary Plane ◽  
Computational Fluid Dynamics Cfd

The duct of a robot vacuum cleaner is the length of the flow channel between the inlet of the rolling brush blower and the outlet of the vacuum blower. To cope with the pressure drop problem of the duct flow field in a robot vacuum cleaner, a method based on Pressure Implicit with Splitting of Operators (PRISO) algorithm is introduced and the optimisation design of the duct flow field is implemented. Firstly, the duct structure in a robot vacuum cleaner is taken as a research object, with the computational fluid dynamics (CFD) theories adopted; a three-dimensional fluid model of the duct is established by means of the FLUENT solver of the CFD software. Secondly, with the k-∊ turbulence model of three-dimensional incompressible fluid considered and the PRISO pressure modification algorithm employed, the flow field numerical simulations inside the duct of the robot vacuum cleaner are carried out. Then, the velocity vector plots on the arbitrary plane of the duct flow field are obtained. Finally, an investigation of the dynamic characteristics of the duct flow field is done and defects of the original duct flow field are analysed, the optimisation of the original flow field has then been conducted. Experimental results show that the duct flow field after optimisation can effectively reduce pressure drop, the feasibility as well as the correctness of the theoretical modelling and optimisation approaches are validated.

scholarly journals Three-Dimensional Wake Decay Inside of a Compressor Cascade and its Influence on the Downstream Unsteady Flow Field: Part I — Wake Decay Characteristics in the Flow Passage

1990 ◽  
Author(s):  
C. Poensgen ◽  
H. E. Gallus
Keyword(s):  
Flow Field ◽  
Turbulent Flows ◽  
Velocity Vector ◽  
Three Dimensional ◽  
Time Dependent ◽  
Major Influence ◽  
Hot Wire ◽  
Compressor Cascade ◽  
Flow Passage ◽  
Turbulent Flow Field

A measuring technique based on multisensor hot-wire anemometry has been developed to determine the unsteady three-dimensional velocity vector and the structure of turbulent flows. It then has been applied to the passage and the exit flow of an annular compressor cascade, which is periodically disturbed by the wakes of a cylinder rotor, located about 50 percent of blade chord upstream. In part I of this paper the decay of the rotor wakes will be described first without stator and secondly through a stator passage. The time-dependent turbulent flow field downstream of this stator is discussed in Part II. The rotor wakes have a major influence on the development of three-dimensional separated regions inside the compressor cascade, and this interaction will be addressed in both parts of this paper.

Numerical Simulation of the Laminar Flow Field in Stirred Tank with Double Layer Combined Impeller Stirring Eccentrically

2015 ◽  
Vol 779 ◽  
pp. 125-132
Author(s):  
Ying Na Liang
Keyword(s):  
Flow Field ◽  
Double Layer ◽  
Three Dimensional ◽  
Stirred Tank ◽  
Flow Structures ◽  
Practical Application ◽  
Three Dimensional Flow ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method ◽  
Multiple Reference

Computational fluid dynamics (CFD) method was applied to study the flow field in cylindrical stirred tank mixing non-Newtonian fluid with double layer combined impeller of upper-straight-blade and lower-inclined-blade. The laminar model and the multiple reference frame (MRF) were employed to simulate the three-dimensional flow field in stirred tank with double layer combined impeller rotating at a constant speed of 200 r/min mixing the mixture of glycerin and water centrally、eccentrically and relative eccentrically, and three different flow structures in stirred tank were obtained. Analyzing the velocity vectors, the velocity contours and the axial、radial and tangent velocity distribution curves, the rule of velocity field with the blade combined form and the stirring structure was discussed. The research provided the valuable reference for the design and practical application of the laminar stirred tank.

The Role of the Hand During Freestyle Swimming

2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Raymond C. Z. Cohen ◽  
Paul W. Cleary ◽  
Bruce R. Mason ◽  
David L. Pease
Keyword(s):  
Fluid Model ◽  
Three Dimensional ◽  
The Body ◽  
Cfd Modeling ◽  
Vortical Structures ◽  
Video Footage ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Computational Fluid Dynamics Cfd ◽  
Lift And Drag

The connections between swimming technique and the fluid dynamical interactions they generate are important for assisting performance improvement. Computational fluid dynamics (CFD) modeling provides a controlled and unobtrusive way for understanding the fundamentals of swimming. A coupled biomechanical–smoothed particle hydrodynamics (SPH) fluid model is used to analyze the thrust and drag generation of a freestyle swimmer. The swimmer model was generated using a three-dimensional laser body scan of the athlete and digitization of multi-angle video footage. Two large distinct peaks in net streamwise thrust are found during the stroke, which coincide with the underwater arm strokes. The hand motions generate vortical structures that travel along the body toward the kicking legs and the hands are shown to produce thrust using both lift and drag. These findings advance understanding of the freestyle stroke and may be used to improve athlete technique.

Effect of Blade Numbers on Pressure Drop of Axial Cyclone Separators by CFD

2011 ◽  
Vol 55-57 ◽  
pp. 343-347 ◽  
Author(s):  
Yi Gang Luan ◽  
Hai Ou Sun
Keyword(s):  
Pressure Drop ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Three Dimensional Model ◽  
Navier Stokes Equations ◽  
Pressure Drops ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method ◽  
Resistance Performance

In this article, computational fluid dynamics(CFD) method is used to predict the effect of blade numbers on the pressure drop of axial cyclone separators. A three-dimensional model is built to acquire the resistance of axial cyclone separators with different blade numbers. The flow field inside cyclone separators is calculated using 3D Reynolds-averaged Navier-Stokes equations. And turbulence model is used to simulate the Reynold stress. Also pressure drop of cyclone separators with different blade numbers is expressed as a function of different inlet velocities. At the same inlet velocity with increasing the blade numbers, pressure drops of cyclones reduce greatly. And changing the blade number of cyclone separator is an effective method to improve its resistance performance.

Laminar Fluid Flow around Two Wall-Mounted Cubes of Arbitrary Configuration

2010 ◽  
Vol 224 (11) ◽  
pp. 2396-2407 ◽  
Author(s):  
M Eslami ◽  
M M Tavakol ◽  
E Goshtasbirad
Keyword(s):  
Fluid Flow ◽  
Flow Field ◽  
Free Stream ◽  
Three Dimensional ◽  
Bluff Bodies ◽  
Vortical Structures ◽  
Laminar Fluid Flow ◽  
Pressure Distributions ◽  
Arbitrary Configuration ◽  
Computational Fluid Dynamics Cfd

The problem of flow field around multiple bluff bodies mounted on a surface is of great significance in different fields of engineering. In this study, a computational fluid dynamics (CFD) code is developed to calculate three-dimensional (3D) steady state laminar fluid flow around two cuboids of arbitrary size and configuration mounted on a surface in free stream conditions. This study presents the results for two cubes of the same size mounted on a surface in both inline and staggered arrangements. Streamlines are plotted for various combinations of the distance between the two cubes and Reynolds number. Moreover, the effects of different parameters on vortical structures, separation, and reattachment points are discussed. Also, velocity and pressure distributions are plotted in the wake region behind the two cubes. It is clearly shown that how the presence of the second cube changes the flow field and the vortical structures in comparison with the case of a single cube.

Numerical Simulation of Flow Process of Ammonium Persulfate Crystallizer

2014 ◽  
Vol 997 ◽  
pp. 396-400
Author(s):  
Yu Guang Fan ◽  
Ting Wei
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Three Dimensional ◽  
Ammonium Persulfate ◽  
Flow Process ◽  
Calculation Results ◽  
Crystallization Effect ◽  
Computational Fluid Dynamics Cfd ◽  
The Impact ◽  
Selection Of

The method of computational fluid dynamics (CFD) is used to three-dimensional numerical simulation for the fluid flow process of ammonium persulfate crystallizer. By using standard model, this paper respectively simulated the flow field within the crystallizer in the impeller installation height of 1.2 m while stirring speed is of 60 r/min, 100 r/min and 200 r/min; and simulated the impact of the flow field inside the crystallizer when the stirring speed of 100 r/min and impeller installation height respectively is of 0.7 m, 1.2 m and 1.7 m. That calculation results show that: the velocity gradient is mainly concentrated in the area of internal draft tube and paddle around. With the increase of impeller speed, the flow velocity of the fluid within the crystallizer corresponding increases; and the energy also gradually decreases from mixing impeller to the settlement zone with the loss of the installation height, and the kinetic energy in the bottom of the crystallizer is reduced. Considering the energy and crystallization effect, selection of mixing speed of 100 r/min or so and installation height of about 1.2 m is more appropriate.

Three-Dimensional Wake Decay Inside of a Compressor Cascade and Its Influence on the Downstream Unsteady Flow Field: Part II—Unsteady Flow Field Downstream of the Stator

1991 ◽  
Vol 113 (2) ◽  
pp. 190-197 ◽  
Author(s):  
C. Poensgen ◽  
H. E. Gallus
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Turbulent Flows ◽  
Velocity Vector ◽  
Three Dimensional ◽  
Time Dependent ◽  
Major Influence ◽  
Hot Wire ◽  
Compressor Cascade ◽  
Turbulent Flow Field

A measuring technique based on multisensor hot-wire anemometry has been developed to determine the unsteady three-dimensional velocity vector and the structure of turbulent flows. It then has been applied to the passage and the exit flow of an annular compressor cascade, which is periodically disturbed by the wakes of a cylinder rotor, located about 50 percent of blade chord upstream. In Part I of this paper the decay of the rotor wakes has been described first without stator and secondly through a stator passage. The time-dependent turbulent flow field downstream of this stator is discussed in Part II of this paper. The rotor wakes have a major influence on the development of three-dimensional separated regions inside the compressor cascade, and this interaction will be addressed in both parts of the paper.

Study on the Field Dynamics of the Seal Cavity Flow Field for High Parameters Bellows Mechanical Seal

2011 ◽  
Vol 99-100 ◽  
pp. 1287-1292
Author(s):  
Wei An Meng ◽  
Mutellip Ahmat ◽  
Nijat Yusup ◽  
Asiye Shavkat
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Three Dimensional ◽  
Cavity Flow ◽  
Mechanical Seal ◽  
Sealing Performance ◽  
Numerical Simulation Methods ◽  
Field Velocity ◽  
Computational Fluid Dynamics Cfd ◽  
The Impact

Based on the computational fluid dynamics (CFD) theory and numerical simulation methods, the seal cavity flow field for the bellows mechanical seal under such the high temperature, high pressure, high-speed as complex working conditions was numerically simulated, and the temperature field, velocity field, pressure field, turbulent kinetic energy and the flow field vorticity distribution of the medium of the seal cavity were obtained, the three-dimensional fluid flow in the seal cavity, the heat transfer characteristics and the impact on the sealing performance were analyzed in this researching.

The Three-Dimensional Unsteady Numerical Analysis of the Internal Flow Field of the New Control Valve

2014 ◽  
Vol 980 ◽  
pp. 112-116
Author(s):  
Dong Yue Qu ◽  
Jia Lei Xu ◽  
Yang Yang Huang ◽  
Xiao Zeng Xie
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Control Valve ◽  
Internal Flow ◽  
Pulse Frequency ◽  
Computational Fluid Dynamics Cfd ◽  
Steam System ◽  
Normal Work ◽  
Vibration Noise

The medium flow of control valve is a typical complex unsteady flow, the internal flow is very unstable which leads to trim or body with vibration of different amplitude, therefore, control valve has been a failure-prone components in the turbine inlet steam system. This paper take the new valve as the research object, by computational fluid dynamics (CFD) software, the numerical simulation of the internal steam steady state flow field of valve normal work a typical opening in the process of opening is made, and obtain the internal flow field visualization distribution and flow characteristics of control valve. Extract unstable place pressure pulsation of the flow field, get the pulse frequency, and provide the basis for the design, optimization and application of low vibration noise control valve.

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