Flow Velocity Coefficient Research on the Coexistence of Pipe Flow and Flow around Pipe

2011 ◽  
Vol 204-210 ◽  
pp. 746-749
Author(s):  
Hong Bing Gao ◽  
Nan Sun ◽  
Liao Yang ◽  
Yu Ma
Keyword(s):  
Flow Field ◽  
Theoretical Basis ◽  
Flow Simulation ◽  
Flow Speed ◽  
Test Rig ◽  
Flow Problems ◽  
Relative Roughness ◽  
Velocity Coefficient ◽  
Definition Of ◽  
Test Result

Based on Darcy - Weisbach route losses equation, this test is focused on the mixed-flow problems at low speed in big flow field, designing the experiment scheme, introducing its principle, and setting up the test rig. According to the test result data, we put forward the definition of flow speed coefficient and draw its curves, and described some related issues, such as reverse pressure phenomenon，reliability of flow simulation, roughness, and so on. The results showed that the flow speed in the pipe will get higher with the flow field increasing, and smaller relative roughness pipes. The flow speed coefficient x≤1 and its curves is monotone decreasing function and will be closer to a fixed value at last with V0’s increasing. This test will provide theoretical basis for increasing fluid energy’s utilization.

scholarly journals Air Flow Simulation and Optimization for Negative Pressure Safflower Harvesting Device

2015 ◽  
Vol 9 (1) ◽  
pp. 773-779 ◽  
Author(s):  
Ge Yun ◽  
Zhang Lixin ◽  
Han Dandan ◽  
Zeng Haifeng ◽  
Zhang Xiang
Keyword(s):  
Flow Field ◽  
Air Flow ◽  
Flow Simulation ◽  
Internal Flow ◽  
Parabolic Type ◽  
Flow Speed ◽  
Low Velocity ◽  
Simulation And Optimization ◽  
Airflow Distribution ◽  
Cone Type

The safflower collection device is an important service part of safflower harvesting device, the number of the air outlets and external structure of air collecting hood are the main factors influencing the effect of the flower’s petals harvesting and collection. However, the design of pneumatic safflower harvest device is based on experience, resulting in long the design cycle, thus increasing the cost of design. Combined with the advantages of computational fluid dynamics software FLUENT, and the internal flow field of safflower closed style cover flowers as the research object, this paper designed gas collecting hood structures with different number of outlets through the analysis of the airflow distribution and motion law. The result of numerical simulation of gas-collecting hood with trapezoidal cone shows higher air flow speed with no low velocity zone, and the distribution of flow field of safflower collected cover with trapezoid cone type is better than that of parabolic type structure. Based on result of simulation, improved the design of the external shape of flowers cover and designed trapezoid cone type to improve the internal airflow state, thus could achieve the goal of improving efficiency of picking and collecting and reduce energy consumption.

scholarly journals Approbation of the Laser Doppler Anemometer Lad-08 on the Secondary Standard Test Rig for Air Flow Speed

2020 ◽  
Vol 1675 ◽  
pp. 012082
Author(s):  
I K Kabardin ◽  
V G Meledin ◽  
S V Dvoinishnikov ◽  
V A Pavlov ◽  
G V Bakakin ◽  
...  
Keyword(s):  
Air Flow ◽  
Flow Speed ◽  
Standard Test ◽  
Laser Doppler Anemometer ◽  
Laser Doppler ◽  
Secondary Standard ◽  
Test Rig

FEM Comparative Analysis of Synchronous Rotor with Different Helix Angle in the Process of Mixing

2012 ◽  
Vol 501 ◽  
pp. 388-392
Author(s):  
Hui Guang Bian ◽  
Wei Shuai Lv ◽  
Chuan Sheng Wang
Keyword(s):  
Comparative Analysis ◽  
Theoretical Basis ◽  
Production Efficiency ◽  
Transient Flow ◽  
Flow Simulation ◽  
Helix Angle ◽  
Original Performance ◽  
Mixing Performance ◽  
Axial Tensile ◽  
Flow Mixing

The paper is used to analyze the structure of traditional synchronous rotor from the perspective which the helix angle between long edge and short edge has some difference. The specialized viscoelastic fluid software--Polyflow is used to dynamic simulation analyze the two different kinds of rotors during the process of flow mixing, and then to analyze the two kinds of rotor performance through the result of transient flow simulation which mixed for one second. The analysis revealed that the improved synchronous rotor had better axial tensile properties in the case of remaining the original performance basically unchanged. And that could improve mixing performance and the production efficiency of mixer more effectively. There will provide a theoretical basis for the optimization of the rotor configuration in future.

The Introduction of Micro Cells to Treat Pressure in Free Surface Fluid Flow Problems

1995 ◽  
Vol 117 (4) ◽  
pp. 683-690 ◽  
Author(s):  
Peter E. Raad ◽  
Shea Chen ◽  
David B. Johnson
Keyword(s):  
Fluid Flow ◽  
Free Surface ◽  
Pressure Field ◽  
Flow Simulation ◽  
New Method ◽  
Computational Domain ◽  
Critical Feature ◽  
Flow Problems ◽  
Macro Cell ◽  
Marker And Cell Method

A new method of calculating the pressure field in the simulation of two-dimensional, unsteady, incompressible, free surface fluid flow by use of a marker and cell method is presented. A critical feature of the new method is the introduction of a finer mesh of cells in addition to the regular mesh of finite volume cells. The smaller (micro) cells are used only near the free surface, while the regular (macro) cells are used throughout the computational domain. The movement of the free surface is accomplished by the use of massless surface markers, while the discrete representation of the free surface for the purpose of the application of pressure boundary conditions is accomplished by the use of micro cells. In order to exploit the advantages offered by micro cells, a new general equation governing the pressure field is derived. Micro cells also enable the identification and treatment of multiple points on the free surface in a single surface macro cell as well as of points on the free surface that are located in a macro cell that has no empty neighbors. Both of these situations are likely to occur repeatedly in a free surface fluid flow simulation, but neither situation has been explicitly taken into account in previous marker and cell methods. Numerical simulation results obtained both with and without the use of micro cells are compared with each other and with theoretical solutions to demonstrate the capabilities and validity of the new method.

EFD and CFD Study of Forces, Ship Motions, and Flow Field for KRISO Container Ship Model in Waves

2020 ◽  
Vol 64 (01) ◽  
pp. 61-80
Author(s):  
Ping-Chen Wu ◽  
Md. Alfaz Hossain ◽  
Naoki Kawakami ◽  
Kento Tamaki ◽  
Htike Aung Kyaw ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Flow Field ◽  
Flow Simulation ◽  
Wake Flow ◽  
Ship Motions ◽  
Container Ship ◽  
Added Resistance ◽  
Ocean Engineering ◽  
Ship Model ◽  
Calm Water

Ship motion responses and added resistance in waves have been predicted by a wide variety of computational tools. However, validation of the computational flow field still remains a challenge. In the previous study, the flow field around the Korea Research Institute for Ships and Ocean Engineering (KRISO) Very Large Crude-oil Carrier 2 tanker model with and without propeller condition and without rudder condition was measured by the authors, as well as the resistance and self-propulsion tests in waves. In this study, the KRISO container ship model appended with a rudder was used for the higher Froude number .26 and smaller block coefficient .65. The experiments were conducted in the Osaka University towing tank using a 3.2-m-long ship model for resistance and self-propulsion tests in waves. Viscous flow simulation was performed by using CFDShip-Iowa. The wave conditions proposed in Computational Fluid Dynamics (CFD) Workshop 2015 were considered, i.e., the wave-ship length ratio λ/L = .65, .85, 1.15, 1.37, 1.95, and calm water. The objective of this study was to validate CFD results by Experimental Fluid Dynamics (EFD) data for ship vertical motions, added resistance, and wake flow field. The detailed flow field for nominal wake and self-propulsion condition will be analyzed for λ/L = .65, 1.15, 1.37, and calm water. Furthermore, bilge vortex movement and boundary layer development on propeller plane, propeller thrust, and wake factor oscillation in waves will be studied.

Experimental Characterization of a Swirl Stabilized MGT Combustor

2015 ◽  
Author(s):  
T. O. Monz ◽  
M. Stöhr ◽  
W. O’Loughlin ◽  
J. Zanger ◽  
M. Hohloch ◽  
...  
Keyword(s):  
Flow Field ◽  
Flow Pattern ◽  
Flame Stabilization ◽  
Main Stage ◽  
Exhaust Gas ◽  
Test Rig ◽  
Gas Emissions ◽  
Preheating Temperature ◽  
Exhaust Gas Emissions

A swirl stabilized MGT combustor (Turbec T100) was operated with natural gas and was experimentally characterized in two test rigs, a pressurized and optically accessible MGT test rig and an atmospheric combustor test rig. For the detailed characterization of the combustion processes, planar OH-PLIF and simultaneous 3D-stereo PIV measurements were performed in the atmospheric combustor test rig. Flow fields, reaction zones and exhaust gas emissions are reported for a range of pressure scaled MGT load points. Parameter studies on combustor inlet conditions (e.g. air preheating temperature, air and fuel mass flow rates and fuel split) were conducted in the atmospheric combustor test rig. From the parameters studies the fuel split between the pilot and the main stage and the air preheating temperature were found to have the biggest impact on the flame shape, flame stabilization and exhaust gas emissions. The measurements of the ATM test rig are compared with measurements of the pressurized MGT test rig with and without an optically accessible combustion chamber. Opened and closed conical flame and flow pattern were found in both test rigs. Reasons for the two flame and flow pattern are supposed to be the interaction of pilot stage combustion and flow field and the interaction of the dilution air with the combustion and the flow field. The results are discussed and compared with repect to a transferability of combustion characteristics from the ATM test rig to the MGT test rigs.

scholarly journals Concept and Essence of the Forensic Study of Personality

2018 ◽  
pp. 186-192
Author(s):  
D. V. Isyutin-Fedotkov
Keyword(s):  
Theoretical Basis ◽  
Academic Discipline ◽  
Russian Language ◽  
Point Of View ◽  
Process Theory ◽  
Term Study ◽  
Approaches To Studying ◽  
The Subject ◽  
Definition Of ◽  
The Russian Language

The article considers and analyzes various opinions on the category "forensic study of personality". From the point of view of the Russian language, the various meanings of the term "study" fully and in a multifaceted way reflect the activities of the investigator in the study of the person in the course of sufficient disclosure and investigation of crimes. It is concluded that forensic study of personality can be considered as a process, theory (doctrine) and part of criminalistics (educational discipline, special course). In this connection, the definition of the term "forensic study of personality" depends on understanding of its essence. Forensic study of personality as a process for the study of personality is associated with activity. Forensic study of the personality as a theory (doctrine) is associated with the objective laws that constitute the subject of criminalistics. Forensic study of the personality as a section of criminalistics (academic discipline, special course) is based on a theoretical basis, on the basis of which methods, approaches to studying personality are considered. The ultimate goal of forensic study of personality is solving the problems of disclosure and investigation of crimes. Author's definitions of the term "forensic study of personality" are proposed.

New Progress of Contemporary Cartography-Navigable Electronic Map

2012 ◽  
Vol 239-240 ◽  
pp. 582-586
Author(s):  
Lin Liu ◽  
Wan Wu Li ◽  
Chen Sun ◽  
Ting Xu
Keyword(s):  
Multimedia Information ◽  
Theoretical Basis ◽  
Development Trend ◽  
Geographic Information ◽  
Electronic Map ◽  
Additional Information ◽  
Thematic Information ◽  
Definition Of ◽  
The Development Trend

The paper gives the definition of the navigable electronic map, generalizes the theoretical basis of the navigable electronic map, analyzes the characteristics of the navigable electronic map from the aspects of the general characteristics, the data and the function, and studies the content of the navigable electronic map including the basic geographic information, the navigable thematic information, the auxiliary multimedia information, the dynamic additional information, and finally points out the development trend of the navigable electronic map.

Sustainable urban land use: Definition, theoretical basis and review of morphology aspect concepts

2009 ◽  
Vol 1 (2) ◽  
pp. 153-170
Author(s):  
Ranka Gajić
Keyword(s):  
Land Use ◽  
Theoretical Basis ◽  
Urban Land ◽  
Urban Land Use ◽  
Point Of View ◽  
Theory And Practice ◽  
Urban Planner ◽  
Starting Point ◽  
Definition Of ◽  
Spatial Entities

The topic of sustainable urban land use compared to the world theory and practice has almost not been elaborated by the professionals in Serbia. This paper's starting point is that it is important to analyze and apply this topic, not only for the master plan level but also for the more detailed levels of planning and for smaller spatial entities/complexes in the cities, focusing on the morphological implications of sustainable urban land use as the topic relevant from the architect/urban planner point of view. After the definition of the notion of sustainable urban land use and the theoretical basis has been defined in the introductory explications, followed by a brief review of that topic's presence in Serbia, the point of view has been explained - namely, focusing on one single aspect (morphology) followed by a review of relevant criteria of other aspects of sustainable urban land use (economical, ecological and social aspects). The conclusion derived by synthesis represents the recommendation for a possible practice/methodology for planner's approach to the sustainable urban land use from the viewpoint of the morphology aspect.

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