A macroscale model for simulating pressure drop and collection efficiency of pleated filters over time

2012 ◽  
Vol 98 ◽  
pp. 344-355 ◽  
Author(s):  
S. Fotovati ◽  
H. Vahedi Tafreshi ◽  
B. Pourdeyhimi
Keyword(s):  
Pressure Drop ◽  
Collection Efficiency ◽  
Pleated Filters ◽  
Over Time

scholarly journals A New Approach of Dedusting for IGCC by a Two-Stage Moving Granular Bed Filter

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2534
Author(s):  
Chiawei Chang ◽  
Yishun Chen ◽  
Litsung Sheng ◽  
Shusan Hsiau
Keyword(s):  
Pressure Drop ◽  
Mass Flow ◽  
Power Plants ◽  
Collection Efficiency ◽  
Size Distributions ◽  
Granular Bed ◽  
Two Stage ◽  
Mass Consumption ◽  
Particulate Size ◽  
Dust Particulate

We propose a dust removal technology in which a two-stage moving granular bed filter was employed using coarse and fine filtering granules. The pressure drop, collection efficiency, and dust particulate size distributions were investigated using various mass flow rates for coarse and fine granules at room temperature. In addition, the ratio of mass consumption was used to reveal the actual mass flow. The ratio of mass consumption influenced the pressure drop, collection efficiency, and dust particulate size distributions. Particulates larger than 1.775 μm were removed by the filter. Our results showed that a mass flow of 330 g/min for coarse granules and a mass flow of 1100 g/min for fine granules provided optimal collection efficiency and particulate size distribution. The proposed design can aid the development of high-temperature systems in power plants.

scholarly journals Grid convergence study of a cyclone separator using different mesh structures

2017 ◽  
Vol 23 (3) ◽  
pp. 311-320 ◽  
Author(s):  
R.A.F. Oliveira ◽  
G.H. Justi ◽  
G.C. Lopes
Keyword(s):  
Pressure Drop ◽  
Collection Efficiency ◽  
Fluid Dynamic ◽  
Two Phase ◽  
Mesh Structure ◽  
Pressure Drops ◽  
Regular Elements ◽  
Grid Convergence ◽  
Grid Convergence Index ◽  
Mesh Structures

In a cyclone design, pressure drop and collection efficiency are two important performance parameters to estimate its implementation viability. The optimum design provides higher efficiencies and lower pressure drops. In this paper, a grid independence study was performed to determine the most appropriate mesh to simulate the two-phase flow in a Stairmand cyclone. Computational fluid dynamic (CFD) tools were used to simulate the flow in an Eulerian-Lagrangian approach. Two different mesh structure, one with wall-refinement and the other with regular elements, and several mesh sizes were tested. The grid convergence index (GCI) method was applied to evaluate the result independence. The CFD model results were compared with empirical correlations from bibliography, showing good agreement. The wall-refined mesh with 287 thousand elements obtained errors of 9.8% for collection efficiency and 14.2% for pressure drop, while the same mesh, with regular elements, obtained errors of 8.7% for collection efficiency and 0.01% for pressure drop.

Longitudinal Effect of Pressure Drop on the Intima-Media Thickening of the Venous Segment of the Arteriovenous Fistula

2013 ◽  
Author(s):  
Ehsan Rajabi-Jaghargh ◽  
Mahesh K. Krishnamoorthy ◽  
Rupak K. Banerjee
Keyword(s):  
Pressure Drop ◽  
Arteriovenous Fistula ◽  
Dialysis Patients ◽  
Luminal Diameter ◽  
Post Surgery ◽  
Opposite Trend ◽  
Venous Stenosis ◽  
Arteries And Veins ◽  
Venous Segment ◽  
Over Time

Venous stenosis is one of the primary causes of the arteriovenous fistula (AVF) maturation-failure and is characterized by vasoconstriction and significant intima-media thickening (IMT). Although the hemodynamic endpoints are believed to play a crucial role in the pathogenesis of venous stenosis, the exact mechanism behind this is unclear. Our hypothesis is that the changes in the pressure drop over time (Δp′) can influence the remodeling factors in AVFs: changes in luminal diameter (ΔDh) and IMT. Curved (C-AVF; n = 3) and straight (S-AVF; n = 3) AVFs were created between the femoral arteries and veins of 3 pigs. CT-scan and ultrasound were utilized to numerically evaluate the flow field, and thus pressure drop in AVFs at 2D (D: days), 7D, and 28D post-surgery. For each AVF, IMT was also measured at 4 histological blocks along the vein. For the C-AVF, the pressure drop consistently decreased over time (from 18.32 mmHg at 2D to 4.58 mmHg at 28D), while opposite trend was found for the S-AVF (from 12.91 mmHg at 2D to 24.49 mmHg at 28D). The Δp′ was negative at all the histology blocks for C-AVF which showed the reduction in the resistance over time due to dilation (positive ΔDh) and outward hypertrophy of the venous segment (positive ΔDh/IMT). In contrast, Δp′ was mostly positive for the S-AVF which showed the increase in the resistance due to vasoconstriction (negative ΔDh) and inward hypertrophy (negative ΔDh/IMT). Thus, measuring Δp′ at the successive post-surgery time points can provide important information on the remodeling behavior of AVFs. Also, creating AVFs in a surgical configuration that can result in negative Δp′ and thus favorable remodeling could influence the life expectancy of the dialysis patients.

Determining the impact of air-side cleaning for heat exchangers in ventilation systems

2019 ◽  
Vol 41 (1) ◽  
pp. 46-59 ◽  
Author(s):  
Akram Abdul Hamid ◽  
Dennis Johansson ◽  
Michael Lempart
Keyword(s):  
Pressure Drop ◽  
Energy Loss ◽  
Heat Exchangers ◽  
Heat Recovery ◽  
Energy Use ◽  
Ventilation System ◽  
Field Measurements ◽  
The Impact ◽  
Over Time ◽  
Ventilation Systems

Cleaning coils can be an efficient way to reduce the need for reparations and maintain the functionality of a ventilation system. This study builds upon existing knowledge concerning the contamination of heat exchangers. Through field measurements on coils and heat-recovery units, a laboratory experiment on a coil, and a generic calculation example, this study determines the impact of sustained contamination on heat-recovery units with regards to energy use. Field measurements made before and after cleaning of heat exchangers show an average increase in the pressure drop by 12% and decrease in the thermal exchange efficiency by 8.1% due to mass deposited on the surface of the heat exchangers. Results from a laboratory test show a correlation between the mass deposited on a coil and (1) the increase in pressure drop over the coil, as well as (2) a diminishing heat exchange. Accumulating contamination on heat-recovery units in residential and commercial buildings (over time) is then linked to increasing pressure drop and diminishing thermal efficiency. With models based on these links, energy loss over time is calculated based on a generic calculation example in a realistic scenario. Practical application: The results from this study emphasize the need for maintenance of buildings with ventilation systems with coils, but more so those with heat-recovery units. The presented field measurements and laboratory study correlate energy loss with sustained accumulation of contaminants on coils and heat-recovery units. These results should serve as a recommendation to property owners considering maintenance of such units in their buildings.

Collection Efficiency and Pressure Drop of Needle Punched Filters

1976 ◽  
Vol 98 (2) ◽  
pp. 675-680 ◽  
Author(s):  
E. M. Afify ◽  
M. H. Mohamed
Keyword(s):  
Pressure Drop ◽  
Unit Area ◽  
Collection Efficiency ◽  
Pressure Rise ◽  
Woven Fabrics ◽  
Dimensionless Form ◽  
Time Duration ◽  
Time Rate ◽  
Concentration Time

Although needle punched fabrics have been used in filtration with increasing success, only meager information is available on their performance characteristics in relation to their unique structure. In this paper an experimental investigation on the performance of needle punched filters is presented. A testing apparatus designed and constructed for this study is described. The pressure drop characteristics of needle punched filters were investigated. The effects of flow rate, packing density, and needling intensity were studied. Experiments were also performed to determine the collection efficiency of needle punched filters using flyash. The effect of flyash concentration, time duration of test, and needling intensity were considered. The role played by the structure in utilizing the mechanisms of collection and reducing the time rate of pressure rise during filtration is discussed. A new scale for measuring the quality of performance of filters using dust and relating, in a dimensionless form, the dust penetration, the pressure drop, and the filter weight per unit area was also developed. Comparison between the performance of commercial woven and needle punched filters demonstrated the superiority of needle punched fabrics over woven fabrics in filtration.

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