Numerical Analysis of Dust Emission by Powder Discharge and Jet Expansion

2015 ◽  
Author(s):  
F. Audard ◽  
P. Fede ◽  
O. Simonin ◽  
E. Belut
Keyword(s):  
Numerical Simulations ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Dust Emission ◽  
Free Fall ◽  
Particulate Flow ◽  
Solid Mass ◽  
Particulate Flows ◽  
Frictional Effects

The paper deals with the Euler-Euler numerical simulation of an experimental study (Ansart et al., 2009 [1]) of freely falling granular jet for investigating the dispersion of dust. The configuration is a bunker, where quasi-static particulate flow takes place, and a free-fall chamber. As a first step, a frictional viscosity model developed by Srivastava and Sundaresan (2003) [2] is implemented to take into account the frictional effects occurring in the quasi-static particulate flows. Without the frictional model for the viscosity, the numerical simulations overpredict the solid mass flow rate at the outlet of the bunker. When using the frictional viscosity, the solid mass flow rate is in better accordance with the experimental value. However, the solid velocity is overestimated in numerical simulations.

scholarly journals On-Sun Performance Evaluation of Alternative High-Temperature Falling Particle Receiver Designs

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Clifford K. Ho ◽  
Joshua M. Christian ◽  
Julius E. Yellowhair ◽  
Kenneth Armijo ◽  
William J. Kolb ◽  
...  
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Efficiency ◽  
Particle Temperature ◽  
Free Fall ◽  
Mass Flow Rates ◽  
Mesh Structures ◽  
Free Falling ◽  
The Impact

This paper evaluates the on-sun performance of a 1 MW falling particle receiver. Two particle receiver designs were investigated: obstructed flow particle receiver versus free-falling particle receiver. The intent of the tests was to investigate the impact of particle mass flow rate, irradiance, and particle temperature on the particle temperature rise and thermal efficiency of the receiver for each design. Results indicate that the obstructed flow design increased the residence time of the particles in the concentrated flux, thereby increasing the particle temperature and thermal efficiency for a given mass flow rate. The obstructions, a staggered array of chevron-shaped mesh structures, also provided more stability to the falling particles, which were prone to instabilities caused by convective currents in the free-fall design. Challenges encountered during the tests included nonuniform mass flow rates, wind impacts, and oxidation/deterioration of the mesh structures. Alternative materials, designs, and methods are presented to overcome these challenges.

scholarly journals The effect of cohesion on the discharge of a granular material through the orifice of a silo

2021 ◽  
Vol 249 ◽  
pp. 08014
Author(s):  
Adrien Gans ◽  
Pascale Aussillous ◽  
Blanche Dalloz ◽  
Maxime Nicolas
Keyword(s):  
Granular Material ◽  
Numerical Simulations ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Experimental Results ◽  
Numerical Investigations ◽  
Silo Discharge

We present the results of both experimental and numerical investigations of the silo discharge for a cohesive granular material. In our study, thanks to a cohesion-controlled granular material (CCGM) we propose to investigate the effect of the cohesive length lc, on the discharge of a silo for two different configurations, one axisymmetrical, and one quasi-2D rectangular silo. In both configurations, an adjustable bottom is used to control the size of the orifice. As observed for cohesionless granular material by previous studies, the mass flow rate and the density through an orifice are mostly controlled by the diameter of the orifice D. The experimental results of the quasi-2D silo are compared with continuum numerical simulations.

Particle abrasion of lifting elbow in dilute pneumatic conveying

2020 ◽  
pp. 135065012095129
Author(s):  
Yun Ji ◽  
Songyong Liu ◽  
Dianrong Gao ◽  
Jianhua Zhao
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Design Method ◽  
Orthogonal Design ◽  
Industrial Applications ◽  
Experimental Results ◽  
Solid Mass ◽  
Airflow Velocity ◽  
Two Phase

Elbows are widely used in various industrial fields and are important for industrial applications. In this study, Eulerian coupling method was used to address the fluid-particle, and particle-particle interactions in a gas-solid two-phase flow while considering the effects of lifting angle, airflow velocity, and solid mass flow rate. The Hertz-Mindlin contact model and empirical Erosion/Corrosion Research Center erosion model were used to predict erosion in a lifting elbow, and the erosion ratio was used for validation with the experimental results. Experimental results indicated that the established model herein is accurate with different airflow velocities and lifting angles. The orthogonal design method was applied to the simulation scheme design, and range and variance analyses were used for the analysis of the results. Results indicated that the solid mass flow rate most affected elbow erosion comparing with lifting angles and airflow velocities. Additionally, the effect of the elbow lifting angle on the erosion mechanism was considered, and results indicated that the maximum erosion region is independent of the airflow velocity, lifting angle, and solid mass flow rate.

High-Pressure Turbine Rim Seal Design for Increased Efficiency

2016 ◽  
Author(s):  
M. Chilla ◽  
H. P. Hodson ◽  
G. Pullan ◽  
D. Newman
Keyword(s):  
High Pressure ◽  
Numerical Simulations ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Main Stream ◽  
Turbine Stage ◽  
High Pressure Turbine ◽  
Disc Space ◽  
Seal Design

In high-pressure turbines, compressor air is used to purge the disc space in an effort to protect the blade roots and the turbine disc from overheating and failure. The purge air exits the disc space through a rim seal at the hub of the main annulus and is subsequently entrained in the rotor hub endwall flows. The introduction of the purge air into the turbine main stream causes additional losses and therefore reduced turbine efficiency. For a given rim sealing mass flow rate, the rim seal geometry has to be designed in a way that reduces the detrimental impact of the sealing flow on turbine performance. In this study, the rim seal of a generic high-pressure turbine, representative of modern large civil aero-engines, is redesigned under consideration of the pressure field upstream of the rotor. Unsteady numerical simulations of the turbine stage are used to compare the aerodynamic impact of three different rim seal designs. The numerical simulations predict an increase in the time-averaged turbine stage efficiency of over 0.2% for the stage configuration with the final redesigned rim seal compared to the configuration with the original baseline rim seal geometry at the nominal sealing mass flow rate.

Machine learning assisted measurement of solid mass flow rate in horizontal pneumatic conveying by acoustic emission detection

2021 ◽  
Vol 229 ◽  
pp. 116083
Author(s):  
Peng Zhang ◽  
Yao Yang ◽  
Zhengliang Huang ◽  
Jingyuan Sun ◽  
Zuwei Liao ◽  
...  
Keyword(s):  
Machine Learning ◽  
Acoustic Emission ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Pneumatic Conveying ◽  
Solid Mass ◽  
Emission Detection

Measurement of solid mass flow rate by a non-intrusive microwave method

2018 ◽  
Vol 323 ◽  
pp. 525-532 ◽  
Author(s):  
Lei Pang ◽  
Yingjuan Shao ◽  
Chamin Geng ◽  
Wenqi Zhong ◽  
Guoyao Liu ◽  
...  
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Microwave Method ◽  
Solid Mass

Performance Evaluation of a High-Temperature Falling Particle Receiver

2016 ◽  
Author(s):  
Clifford K. Ho ◽  
Joshua M. Christian ◽  
Julius Yellowhair ◽  
Kenneth Armijo ◽  
William J. Kolb ◽  
...  
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Efficiency ◽  
Particle Temperature ◽  
Free Fall ◽  
Mass Flow Rates ◽  
Mesh Structures ◽  
Free Falling ◽  
The Impact

This paper evaluates the on-sun performance of a 1 MW falling particle receiver. Two particle receiver designs were investigated: obstructed flow particle receiver vs. free-falling particle receiver. The intent of the tests was to investigate the impact of particle mass flow rate, irradiance, and particle temperature on the particle temperature rise and thermal efficiency of the receiver for each design. Results indicate that the obstructed flow design increased the residence time of the particles in the concentrated flux, thereby increasing the particle temperature and thermal efficiency for a given mass flow rate. The obstructions, a staggered array of chevron-shaped mesh structures, also provided more stability to the falling particles, which were prone to instabilities caused by convective currents in the free-fall design. Challenges encountered during the tests included non-uniform mass flow rates, wind impacts, and oxidation/deterioration of the mesh structures. Alternative materials, designs, and methods are presented to overcome these challenges.

Experimental and Numerical Heat Transfer on a Cylinder Cooled by Two Rectangular Jets of Different Heights

2012 ◽  
Author(s):  
Fabio Gori ◽  
Ivano Petracci ◽  
Matteo Angelino
Keyword(s):  
Heat Transfer ◽  
Numerical Simulations ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Maximum Heat ◽  
Optimal Position ◽  
Nusselt Numbers ◽  
Cylinder Diameter ◽  
Maximum Heat Transfer

The present paper presents experimental measurements of heat transfer on a cylinder, cooled by two rectangular jets of the same width but different height, H, in order to investigate the influence of the jet height on the local and the average cooling rates, because one of the problems in the heat transfer with jet flow is the convenience to choose the height of the jet in comparison to the height of the impinged object. The cylinder, heated by electric current, is set at several distances from the jet exit, x, on the symmetrical plane of symmetry, i.e. in a two-dimensional geometry, in order to find the optimal position which realizes the maximum heat transfer. The experimental heat transfer on the impingement shows that the local Nusselt number, defined with the cylinder diameter, D, is greater for the smaller slot because velocity is slightly higher but the average Nusselt numbers, defined with the cylinder diameter, D, are quite similar because the higher slot has a greater surface of impingement. Local and average Nusselt numbers are in qualitative agreement only if are compared with the same dimensionless distance, x/H, which can be interpreted as the ratio Rex/ReH, which is per unit of mass flow rate or is independent of the mass flow rate. Numerical simulations are carried out with a two-equations turbulent model using the RNG k-ε approach, on a cylinder with the same thickness of the experiments or without thickness. The numerical simulations of the cylinder without thickness are in acceptable agreement for what concern the average Nusselt numbers. The local Nusselt numbers are in fair agreement only if the cylinder has the thickness of the experiments, independently of the heat flow conditions, i.e. uniformly throughout the thickness or from the inner surface.

scholarly journals Determination of a Methodology to Derive Correlations Between Window Opening Mass Flow Rate and Wind Conditions Based on CFD Results

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1600 ◽  
Author(s):  
Panagiotis Stamatopoulos ◽  
Panagiotis Drosatos ◽  
Nikos Nikolopoulos ◽  
Dimitrios Rakopoulos
Keyword(s):  
Wind Speed ◽  
Numerical Simulations ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Empirical Equation ◽  
Ventilation Rate ◽  
Cfd Simulations ◽  
Air Mass ◽  
Adjacent Room

This paper presents a methodology for the development of an empirical equation which can provide the air mass flow rate imposed by single-sided wind-driven ventilation of a room, as a function of external wind speed and direction, using the results from Computational Fluid Dynamics (CFD) simulations. The proposed methodology is useful for a wide spectrum of applications, in which no access to experimental data or conduction of several CFD runs is possible, deriving a simple expression of natural ventilation rate, which can be further used for energy analysis of complicated building geometries in 0-D models or in object-oriented software codes. The developed computational model simulates a building, which belongs to Rheinisch-Westfälische Technische Hochschule (RWTH, Aachen University, Aachen, Germany) and its surrounding environment. A tilted window represents the opening that allows the ventilation of the adjacent room with fresh air. The derived data from the CFD simulations for the air mass flow were fitted with a Gaussian function in order to achieve the development of an empirical equation. The numerical simulations have been conducted using the Ansys Fluent v15.0® software package. In this work, the k-w Shear Stress Transport (SST) model was implemented for the simulation of turbulence, while the Boussinesq approximation was used for the simulation of the buoyancy forces. The coefficient of determination R2 of the curve is in the range of 0.84–0.95, depending on the wind speed. This function can provide the mass flow rate through the open window of the investigated building and subsequently the ventilation rate of the adjacent room in air speed range from 2.5 m/s to 16 m/s without the necessity of further numerical simulations.

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