Challenging Paradigms by Optimizing Combustible Dust Separator

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
Wayne Strasser ◽  
Alex Strasser
Keyword(s):  
High Speed ◽  
Computational Study ◽  
Flow Distribution ◽  
Computational Design ◽  
Particulate Material ◽  
Dust Collector ◽  
Mixed Effect ◽  
Industrial Dust ◽  
Negative Effect ◽  
Dust Separator

A computational study was carried out to investigate the effects of internal geometry changes on the likelihood of solids buildup within, and the efficiency of, an industrial dust collector. Combustible solids held up in the unit pose a safety risk. The dust collector serves multiple functions, so the design requires a delicate balance. Particles should be separated from the incoming mixture and collected in the bottom of the unit. This particulate material should freely flow into a high-speed ejector (Mach 0.4) underneath. Gas must also flow freely to the top outlet, but sufficient gas must flow down to the ejector so that its motive gas augments the transport of particles back to the reactor (recirculation). Computational design evaluations included: (1) rod spacing, (2) ledge removal, and (3) rod cover plates. Testing on particle size distribution and density was carried out in-house to provide inputs to the computational fluid dynamics (CFD) model. Rod spacing reduction had a mixed effect on flow distribution. Plates were found to induce a negative effect on recirculation and a mixed effect on combustible solids accumulation. Removal of the ledge, however, offered slightly more recirculation along with completely alleviating stagnant solids accumulation. It is shown that, without consideration of detailed fluid physics, general separator design principals might be misguiding.

Investigation of Dust Separator Design and Risk Mitigation

2017 ◽  
Author(s):  
Wayne Strasser ◽  
Alex Strasser
Keyword(s):  
High Speed ◽  
Risk Mitigation ◽  
Computational Study ◽  
Flow Distribution ◽  
Computational Design ◽  
Particulate Material ◽  
Dust Collector ◽  
Mixed Effect ◽  
Industrial Dust ◽  
Negative Effect

A computational study was carried out to investigate the effects of internal geometry changes on the likelihood of solids buildup within, and the efficiency of, an industrial dust collector. Combustible solids held up in the unit pose a safety risk. The dust collector serves multiple functions, so the design requires a delicate balance. Particles should be separated from the incoming mixture and collected in the bottom of the unit. This particulate material should freely flow into a high-speed ejector (Mach 0.4) underneath. Gas must also flow freely to the top outlet, but sufficient gas must flow down to the ejector so that its motive gas augments the transport of particles back to the reactor (“recirculation”). Computational design evaluations included 1) rod spacing, 2) ledge removal, and 3) rod cover plates. Testing on particle size distribution and density were carried out in-house to provide inputs to the CFD model. Rod spacing reduction had a mixed effect on flow distribution. Plates were found to induce a negative effect on recirculation and a mixed effect on combustible solids accumulation. Removal of the ledge, however, offered slightly more recirculation along with completely alleviating stagnant solids accumulation. It is shown that, without consideration of detailed fluid physics, general separator design principals might be misguiding.

Effect of education on migration decisions in Ghana: a rural-urban perspective

2016 ◽  
Vol 43 (2) ◽  
pp. 336-356 ◽  
Author(s):  
Franklin Amuakwa-Mensah ◽  
Louis Boakye-Yiadom ◽  
William Baah-Boateng
Keyword(s):  
Educational Attainment ◽  
Rural Areas ◽  
Migration Decision ◽  
Skilled Workers ◽  
Mixed Effect ◽  
Content Type ◽  
Rural And Urban ◽  
Migration Decisions ◽  
Negative Effect ◽  
The Impact

Purpose – The purpose of this paper is to investigate the effect of education on migration decisions focusing on rural and urban in-migrants by comparing the 2005/2006 and 2012/2013 rounds of the Ghana Living Standards Survey (GLSS5 and GLSS6). After correcting for selectivity bias, the authors observed that anticipated welfare gain and socio-economic variables such as sector of employment, sex, experience, age, educational level and marital status significantly affect an individual’s migration decision. Design/methodology/approach – The authors made use of Sjaastad’s (1962) human capital framework as a basis for examining the impact of education on migration. The migration decision equation was based on the Heckman two stage procedure. Findings – While educational attainment is observed to have a positive effect on migration decision in the period 2005/2006, the authors find a negative effect of educational attainment on migration decision in the period 2012/2013. The effect of educational attainment on migration decision in 2005/2006 for urban in-migrant is higher than the effect for rural in-migrant, with its significance varying for the different stages of educational attainment. In absolute terms, whereas the effect of secondary educational attainment on migration decisions for urban in-migrant is higher than that of rural in-migrant, the reverse holds for higher educational attainment during the period 2012/2013. Social implications – Based on the mixed effect of education on migration decision as evident from the study, policies to enhance the educational system in Ghana should be complemented with job creations in the entire country. Moreover, special attention should be given to the rural sector in such a way that the jobs to be created in the sector do not require skilled workers. With quality education and job creation, the welfare of individuals living in urban and rural areas will be enhanced. Originality/value – In spite of the importance of education in migration decisions, there is scanty literature on the rural-urban dimension. To the best of the author’s knowledge there is no literature in the Ghanaian context which examines the rural and urban perspective of the impact of education on migration with a much recent data. Further, the author consider how the determinants of migration decision have changed over time focusing on rural and urban perspectives.

scholarly journals Analysis and control of flow at suction connection in high-speed centrifugal pump

2017 ◽  
Vol 9 (1) ◽  
pp. 168781401668529 ◽  
Author(s):  
Wen-wu Song ◽  
Li-chao Wei ◽  
Jie Fu ◽  
Jian-wei Shi ◽  
Xiu-xin Yang ◽  
...  
Keyword(s):  
Flow Field ◽  
Centrifugal Pump ◽  
High Speed ◽  
Internal Flow ◽  
Orifice Plate ◽  
Centrifugal Pumps ◽  
Pressure Area ◽  
Negative Effect ◽  
And Control ◽  
Experimental Data Analysis

The backflow vortexes at the suction connection in high-speed centrifugal pumps have negative effect on the flow field. Setting an orifice plate in front of the inducer is able to decrease the negative effect caused by backflow vortexes. The traditional plate is able to partially control the backflow vortexes, but a small part of the vortex is still in the inlet and the inducer. Four new types of orifice plates were created, and the control effects on backflow vortexes were analyzed. The ANSYS-CFX software was used to numerically simulate a high-speed centrifugal pump. The variations of streamline and velocity vectors at the suction connection were analyzed. Meanwhile, the effects of these plates on the impeller pressure and the internal flow field of the inducer were analyzed. Numerically, simulation and experimental data analysis methods were used to compare the head and efficiency of the high-speed pumps. The results show that the C-type orifice plate can improve the backflow vortex, reduce the low-pressure area, and improve the hydraulic performance of the high-speed pump.

scholarly journals Cotton Imports and GDP of Indonesia- Cointegration Analysis

2021 ◽  
pp. 149-154
Author(s):  
P. Soumya ◽  
R. A. Yeledhalli
Keyword(s):  
High Speed ◽  
Cointegration Analysis ◽  
Causality Analysis ◽  
The Real ◽  
Real Gdp ◽  
Use Of Technology ◽  
Long Run ◽  
Negative Effect ◽  
The Government ◽  
The Impact

The study examines the impact of cotton imports on the real GDP (Gross Domestic Product) of Indonesia for a period from 1992 to 2018 using ARDL approach and Granger causality analysis. Results of the study indicated that cotton imports have negative effect on economic growth. For every 1% increase in cotton imports the real GDP decreased by 0.107% in the long run. Any disequilibrium in the model is adjusted with a high speed of adjustment of 107.7% in less than a year. Shocks and the trend are adjusted in less than one year. There is no causality between imports of cotton and the real GDP. The study suggested effort should be taken by the government to increase yield of cotton by the use of technology and also a need to initiate farmers to take up cotton farming. 

Computational Design and Analysis of Nitinol-Based Arch Wedge Support

2018 ◽  
Author(s):  
Tyler Stranburg ◽  
Yucheng Liu ◽  
Harish Chander ◽  
Adam Knight
Keyword(s):  
Boundary Conditions ◽  
Mechanical Response ◽  
Computational Study ◽  
Experimental Testing ◽  
Permanent Deformation ◽  
Computational Design ◽  
Element Analysis ◽  
Human Movements ◽  
First Time ◽  
Human Motions

A nitinol-based arch wedge support (AWS) was designed using computational approach. Finite element analysis (FEA) was performed to on this design to assess the influence of loading, boundary conditions, and thickness on the mechanical response of the computer-aid design (CAD) model. Five loading conditions caused by different human movements, two boundary conditions, and three thicknesses are involved in this computational study. FEA results showed that the presented AWS design can resist forces caused by different human motions without generating any permanent deformation. The study features the first time to design and evaluate a thin-walled nitinol AWS model. The results of this study form the background of prototyping and experimental testing of the design in the next phase.

Hot Gas Filtration in Co-Generation Power Plants

2003 ◽  
Author(s):  
M. H. Al-Hajeri ◽  
M. R. Al-Ajmi
Keyword(s):  
Power Plants ◽  
Computational Study ◽  
Cross Flow ◽  
Deposition Process ◽  
Particulate Material ◽  
Gas Filtration ◽  
Physical Damage ◽  
Hot Gas ◽  
Hot Gas Filtration ◽  
Face Velocity

This paper reports a computational study using CFD on a hot gas filter in cross flow arrangement. The filter generally operates with the dirty gases passing through the filter elements, the particulate material being deposited on the outside of the filter. However, in power co-generation plants, hot gas filtration is needed to allow the hot exhaust gases to be fed to a turbine without causing any physical damage to the blades. The aim of this work is to increase understanding of the deposition process and the factors that affect the build up of the filter cake. A parametric investigation is undertaken with particular emphasis on the effects of the ratio of the approach cross flow velocity to filter face velocity on the deposition pattern as a function of the particle size (1 to 100 microns). Velocity fields and particle tracks are presented, in addition to the radius of convergence which is a parameter that characterizes the deposition process for each flow regime.

scholarly journals Experimental and Computational Study of Trapped Vortex Combustor Sector Rig with High-Speed Diffuser Flow

2001 ◽  
Vol 7 (6) ◽  
pp. 375-385 ◽  
Author(s):  
R. C. Hendricks ◽  
D. T. Shouse ◽  
W. M. Roquemore ◽  
D. L. Burrus ◽  
B. S. Duncan ◽  
...  
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Fuel Injection ◽  
Computational Study ◽  
Combustion Efficiency ◽  
Flame Stabilization ◽  
Performance Data ◽  
Pollutant Emissions ◽  
Choked Flow ◽  
Trapped Vortex

The Trapped Vortex Combustor (TVC) potentially offers numerous operational advantages over current production gas turbine engine combustors. These include lower weight, lower pollutant emissions, effective flame stabilization, high combustion efficiency, excellent high altitude relight capability, and operation in the lean burn or RQL modes of combustion. The present work describes the operational principles of the TVC, and extends diffuser velocities toward choked flow and provides system performance data. Performance data include EINOx results for various fuel-air ratios and combustor residence times, combustion efficiency as a function of combustor residence time, and combustor lean blow-out (LBO) performance. Computational fluid dynamics (CFD) simulations using liquid spray droplet evaporation and combustion modeling are performed and related to flow structures observed in photographs of the combustor. The CFD results are used to understand the aerodynamics and combustion features under different fueling conditions. Performance data acquired to date are favorable compared to conventional gas turbine combustors. Further testing over a wider range of fuel-air ratios, fuel flow splits, and pressure ratios is in progress to explore the TVC performance. In addition, alternate configurations for the upstream pressure feed, including bi-pass diffusion schemes, as well as variations on the fuel injection patterns, are currently in test and evaluation phases.

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