Numerical calculation of the dynamic behavior of solid particles through the inlet box with complex geometry of a fluid machine

1993 ◽  
Vol 2 (4) ◽  
pp. 231-236
Author(s):  
Shengli Hu ◽  
Keqi Wu ◽  
Shangmo Cheng
Keyword(s):  
Numerical Calculation ◽  
Dynamic Behavior ◽  
Complex Geometry ◽  
Solid Particles ◽  
Inlet Box

Dynamic Analysis of Small Scale Floating Structure by Ship Wave Force

2009 ◽  
Author(s):  
Hiroaki Eto ◽  
Shigenori Yuasa ◽  
Kohei Wada ◽  
Osamu Saijo ◽  
Kiyotaka Ohki
Keyword(s):  
Numerical Calculation ◽  
Dynamic Behavior ◽  
Wave Height ◽  
Water Area ◽  
Tokyo Bay ◽  
Small Scale ◽  
Wave Forces ◽  
Floating Structure ◽  
Ship Waves ◽  
Ship Wave

A floating structure has many options for effective ocean space utilization, for instance, the well known floating airport project, called Mega-Float. But after the end of the project, small scale floating structure began to be paid to attention. As the good example of such a kind of floating structure, there is the floating restaurant named “WATERLINE” (Figure 1) in Tokyo Bay. “WATERLINE” is small scale floating structure, and it is moored at the Tennoz Canal that is the closed water area. Therefore, when the ship passes around the floating restaurant, ship wave forces give a great influence on dynamic behavior of floating restaurant. As for ship waves, several studies have been made on the wave resistance and influence on ship handling concerning ship waves, but it is hardly to find papers focused on influence that ship wave forces give to dynamic behavior of small scale floating structure. In this research, dynamic behavior of small scale floating structure by ship wave forces was studied through both theoretical and experimental approach. As for the theoretical analysis, the equations of the Boussinesq type to treat shallow water area were adopted, and ADI (Alternating Direction Implicit) method in a numerical calculation was used for the analysis of these equations. And the floating structure was assumed to be a rigid body, and the displacement responses by ship wave forces were analyzed. With regard to experimental study, dynamic behavior of “WATERLINE” and wave height by the ship wave were actually measured. This measurement data is a profitable basic data for other researchers and engineers in order to analyze a floating structure. In the present paper, the validity of the numerical calculation program for ship wave response analysis was verified by the comparison between calculation results and the measurement results, the characteristics of the displacement response and the wave height were discussed by the numerical results that had been obtained by changing by the ship’s speed and the distance between floating structure and the ship. In addition, the evaluation of habitability in vertical motion of the small scale floating structure at the canal was examined by the diagram proposed from our research results [1], [2]. And, in regard to the ship that passes over around floating structure, ship’s speed limit and minimum distance between the ship and the floating structure were proposed.

scholarly journals Radiation Heat Transfer in a Complex Geometry Containing Anisotropically-Scattering Mie Particles

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3986 ◽  
Author(s):  
Ali Ettaleb ◽  
Mohamed Abbassi ◽  
Habib Farhat ◽  
Kamel Guedri ◽  
Ahmed Omri ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Fly Ash ◽  
Complex Geometry ◽  
Radiation Heat Transfer ◽  
Solid Particles ◽  
Isotropic Scattering ◽  
Isotropic Case ◽  
Radiation Heat ◽  
Radiation Heat Flux

This study aims to numerically investigate the radiation heat transfer in a complex, 3-D biomass pyrolysis reactor which is consisted of two pyrolysis chambers and a heat recuperator. The medium assumes to be gray, absorbs, emits, and Mie-anisotropically scatters the radiation energy. The finite volume method (FVM) is applied to solve the radiation transfer equation (RTE) using the step scheme. To treat the complex geometry, the blocked-off-region procedure is employed. Mie equations (ME) are applied to evaluate the scattering phase function and analyze the angular distribution of the anisotropically scattered radiation by particles. In this study, three different states are considered to test the anisotropic scattering impacts on the temperature and radiation heat flux distribution. These states are as: (i) Isotropic scattering, (ii) forward and backward scattering and (iii) scattering with solid particles of different coals and fly ash. The outcomes demonstrate that the radiation heat flux enhances by an increment of the albedo and absorption coefficients for the coals and fly ash, unlike the isotropic case and the forward and backward scattering functions. Moreover, the particle size parameter does not have an important influence on the radiation heat flux, when the medium is thin optical. Its effect is more noticeable for higher extinction coefficients.

Dynamic Behavior of Solid Particles Suspended by Polluted Flow in a Turbine Stage

1973 ◽  
Vol 10 (7) ◽  
pp. 434-440 ◽  
Author(s):  
M. Fathy Hussein ◽  
W. Tabakoff
Keyword(s):  
Dynamic Behavior ◽  
Solid Particles ◽  
Turbine Stage

Prediction of Hydraulic Inductance

2002 ◽  
Author(s):  
D. Nigel Johnston
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Calculation ◽  
Dynamic Response ◽  
Complex Geometry ◽  
Fluid Power ◽  
Poppet Valve ◽  
Noise Characteristics ◽  
Spool Valve

The dynamic response, stability and fluid-borne noise characteristics of fluid power components and systems can be strongly influenced by the inertia or ‘hydraulic inductance’ of the fluid in passageways, which are often of complex geometry. The hydraulic inductance is a parameter that has often proved to be very difficult to quantify accurately, either theoretically or experimentally. This paper presents a method of numerical calculation of the hydraulic inductance in a passageway. The method is simple to apply and can be applied to geometries of arbitrary complexity. A simple way of using a Computational Fluid Dynamics package for calculating hydraulic inductance is also demonstrated. Results are presented for a simple cylindrical orifice, a simple spool valve and a conical poppet valve. The effect of the inductance on the response of a poppet valve is demonstrated.

Hydrodynamic Characteristics of Free Rise of Light Spheres and Bubbles in Newtonian and Non-Newtonian Liquids

2008 ◽  
Vol 591-593 ◽  
pp. 785-790 ◽  
Author(s):  
F.R.G. Melo ◽  
Marcos A.S. Barrozo ◽  
Carlos Henrique Ataíde
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Dynamic Behavior ◽  
Gas Bubbles ◽  
Free Fall ◽  
Solid Particles ◽  
Hydrodynamic Characteristics ◽  
Light Particles ◽  
Newtonian Liquids

Some authors showed that the results obtained for the movement of particle fall in liquids could not be extended to describe the rising of light particles with the same diameter in the same difference of density conditions, especially in the region of higher Reynolds number. The main objective of this study was the investigation of the dynamic behavior of light spheres and of gas bubbles isolated in stagnant liquids. The experimental data of the rising of light spheres and bubbles were obtained with photographic techniques and a stroboscope. The obtained results showed that there were significant differences between the behavior of the ascending gas bubbles and the solid particles in free fall.

Mathematical modeling of gas-dynamic processes in a pulsed aerodynamic facility and the numerical calculation of flow parameters in the test chamber

2019 ◽  
Author(s):  
Н.П. Скибина
Keyword(s):  
Numerical Calculation ◽  
Mathematical Modelling ◽  
Numerical Solution ◽  
Nozzle Exit ◽  
Gas Flow ◽  
Complex Geometry ◽  
Test Chamber ◽  
The Body ◽  
Flow Parameters ◽  
Cone Model

Описывается математическое моделирование газодинамических процессов, протекающих в основных функциональных частях импульсной аэродинамической установки. Осуществляется расчет локальных и интегральных параметров обтекания модели конуса, расположенной в рабочей части установки. Приводится качественное и количественное сравнение результатов математического и физического моделирования. Purpose.The aim of this paper is the mathematical modelling of gasdynamic processes and the incoming airflow around the model fixed in the test chamber of the main functional elements of a pulsed aerodynamic facility. Methodology.Physical and mathematical modelling methods are jointly used for comprehensive description of the processes under study. The experimentally obtained results of drainage and balance measurements combined with visualization of the flow around the model using the shadow method are used to validate the numerical solution of the problem. System of unsteady Reynolds averaged NavierStokes (RANS) equations and SST turbulence model are used for mathematical description of the movement of working gas flow from prechamber through the nozzle to the test chamber where the body was fixed. Finite elements method implemented in Ansys Fluent computational complex is used for the numerical solution. Findings.Mathematical modelling of the flow around the cone model by the incoming flow with Mach numbers M 2...5 was carried out. The distribution fields of gasdynamic parameters (,P,T,M) over the entire internal volume of the pulsed aerodynamic facility (prechamber, axisymmetric nozzles set, test chamber) are obtained. The values of static pressure at the model surface and Mach number at nozzle exit are calculated for each velocity. Relative error between numerical calculation and experimental data is obtained to be of the order of 10 and 3, respectively. For flow structure near the model we obtain a qualitative agreement that the density distribution field is identical to the shadowgraph flow visualization pattern. Value.A numerical method for calculation of local and integral parameters of supersonic and hypersonic flow around models in test chamber of aerodynamic facility was implemented. Information about the gasdynamic flow parameters at the nozzle exit allowing the study of the flow around the model for the cases with more complex geometry using mathematical modelling based on the results of experiments.

Prediction of Fluid Inertance in Nonuniform Passageways

2006 ◽  
Vol 128 (2) ◽  
pp. 266-275 ◽  
Author(s):  
D. Nigel Johnston
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Finite Element ◽  
Numerical Calculation ◽  
Incompressible Flow ◽  
Complex Geometry ◽  
Mean Flow ◽  
Poppet Valve ◽  
Noise Characteristics ◽  
Spool Valve

The dynamic response, stability, and noise characteristics of fluid components and systems can be strongly influenced by the inertance of the fluid in passageways, which are often of complex geometry. The inertance is a parameter that has often proved to be very difficult to accurately quantify, either theoretically or experimentally. This paper presents a method of numerical calculation of the inertance in a passageway, assuming inviscid, incompressible flow and zero mean flow. The method is simple to apply and can be applied to geometries of arbitrary complexity. Two simple but unorthodox ways of calculating inertance using a computational fluid dynamics and a finite element solid-modeling package are also demonstrated. Results are presented for a simple cylindrical orifice, a simple spool valve, and a conical poppet valve. The effect of the inertance on the response of a poppet valve is demonstrated.

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