scholarly journals EFFECT OF PARTICLE-SIZE AND AIR FLOW RATES ON THE IGNITION TEMPERATURE OF SUB BITUMINOUS COAL

2016 ◽  
Vol 3 (10) ◽  
pp. 89-97 ◽  
Keyword(s):  
Particle Size ◽  
Ignition Temperature ◽  
Bituminous Coal ◽  
Air Flow ◽  
Flow Rates ◽  
Effect Of Particle Size

149 Evaluation of Hammermill Tip Speed, Air Assist, and Screen Hole Diameter on Ground Corn Characteristics

2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 134-135
Author(s):  
Michaela B Braun ◽  
Kara M Dunmire ◽  
Michael Sodak ◽  
Jerry Shepherd ◽  
Randy Fisher ◽  
...  
Keyword(s):  
Particle Size ◽  
Geometric Mean ◽  
Air Flow ◽  
Hole Diameter ◽  
Experimental Unit ◽  
Flow Index ◽  
Air Flow Rate ◽  
Flow Rates ◽  
Composite Flow ◽  
Ground Corn

Abstract This study was performed to evaluate hammermill tip speed, assistive airflow and screen hole diameter on hammermill throughput and characteristics of ground corn. Corn was ground using two Andritz hammermills (Model: 4330–6, Andritz Feed & Biofuel, Muncy,PA) measuring 1-m in diameter each equipped with 72 hammers and 300 HP motors. Treatments were arranged in a 3 × 3 × 3 factorial design with 3 tip speeds (3,774, 4,975, and 6,176 m/min), 3 screen hole diameters (2.3, 3.9 and 6.3 mm), and 3 air flow rates (1,062, 1,416, and 1,770 fan RPM). Corn was ground on 3 separate days to create 3 replications and treatments were randomized within day. Samples were collected and analyzed for moisture, particle size, and flowability characteristics. Data were analyzed using the GLIMMIX procedure of SAS 9.4 with grinding run serving as the experimental unit and day serving as the block. There was a 3-way interaction for standard deviation (Sgw), (linear screen hole diameter × linear hammer tip speed × linear air flow, P = 0.029). There was a screen hole diameter × hammer tip speed interaction (P < 0.001) for geometric mean particle size dgw (P < 0.001) and composite flow index (CFI) (P < 0.001). When tip speed increased from 3,774 to 6,176 m/min the rate of decrease in dgw was greater as screen hole diameter increased from 2.3 to 6.3 mm resulting in a 67, 111, and 254 µm decrease in dgw for corn ground using the 2.3, 3.9, and 6.3 mm screen hole diameter, respectively. For CFI, increasing tip speed decreased the CFI of ground corn when ground using the 3.9 and 6.3 mm screen. However, when grinding corn using the 2.3 mm screen, there was no evidence of difference in CFI when increasing tip speed. In conclusion, the air flow rate did not influence dgw of corn but hammer tip speed and screen size were altered and achieved a range of dgw from 304 to 617 µm.

scholarly journals Magnetizing Roast for Chalcopyrite: Effect of Particle Size and Dilution

1984 ◽  
Vol 1 (3) ◽  
pp. 115-122
Author(s):  
Irina Makarow ◽  
Thomas Agrafiotis ◽  
James A. Finch
Keyword(s):  
Particle Size ◽  
Ignition Temperature ◽  
Copper Ferrite ◽  
Effect Of Particle Size ◽  
Magnetic Product

In excess oxvgen, 0-37 μm CuFeS2 became magnetic at a temperature of 280ºc. The magnetic product is copper ferrite, CuO.Fe203. The ‘magnetizing’ temperature increased with particle size apparently following the trend reported for the ignition temperature. Dilution increased the magnetizing temperature; 80% dilution by PbS, MoS2 or SiO2 increases the temperature from 280ºC to over 420ºC. Sinterina was a concurrent reaction. Nevertheless, a chalcopyrite/ galena mixture after roasting and gentle grinding was readily separated on a Davis tube.

Computational Fluid Dynamics Simulation of Flow of Exhaled Particles From Powered-Air Purifying Respirators

2019 ◽  
Author(s):  
Susan S. Xu ◽  
Zhipeng Lei ◽  
Ziqing Zhuang ◽  
Michael Bergman
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Particle Size ◽  
Simulation Study ◽  
Particle Concentration ◽  
Air Flow ◽  
Dynamics Simulation ◽  
Cfd Modeling ◽  
Particle Sizes ◽  
Flow Rates

Abstract In surgical settings, infectious particulate wound contamination is a recognized cause of post-operative infections. Powered air-purifying respirators (PAPRs) are widely used by healthcare workers personal protection against infectious aerosols. Healthcare infection preventionists have expressed concern about the possibility that infectious particles expelled from PAPR exhalation channels could lead to healthcare associated infections, especially in operative settings where sterile procedural technique is emphasized. This study used computational fluid dynamics (CFD) modeling to simulate and visualize the distribution of particles exhaled by the PAPR wearer. In CFD simulations, the outward release of the exhaled particles, i.e., ratio of exhaled particle concentration outside the PAPR to that of inside the PAPR, was determined. This study also evaluated the effect of particle sizes, supplied air flow rates, and breathing work rates on outward leakage. This simulation study for the headform and loose-fitting PAPR system included the following four main steps: (1) preprocessing (establishing a geometrical model of a headform wearing a loose-fitting PAPR by capturing a 3D image), (2) defining a mathematical model for the headform and PAPR system, and (3) running a total 24 simulations with four particle sizes, three breathing workloads and two supplied-air flow rates (4 × 3 × 2 = 24) applied on the digital model of the headform and PAPR system, and (4) post-processing the simulation results to visually display the distribution of exhaled particles inside the PAPR and determine the particle concentration of outside the PAPR compared with the concentration inside. We assume that there was no ambient particle, and only exhaled particles existed. The results showed that the ratio of the exhaled particle concentration outside to inside the PAPR were influenced by exhaled particle sizes, breathing workloads, and supplied-air flow rates. We found that outward concentration leakage from PAPR wearers was approximately 9% with a particle size of 0.1 and 1 μm at the light breathing and 205 L/min supplied-air flow rates, which is similar to the respiratory physiology of a health care worker in operative settings, The range of the ratio of exhaled particle concentration leaking outside the PAPR to the exhaled particle concentration inside the PAPR is from 7.6% to 49. We found that supplied air flow rates and work rates have significant impact on outward leakage, the outward concentration leakage increased as particle size decreased, breathing workload increased, and supplied-air flow rate decreased. The results of our simulation study should help provide a foundation for future clinical studies.

scholarly journals Evaluation of Hammermill Tip Speed, Air Assist and Screen Hole Diameter on Ground Corn Characteristics

Processes ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1768
Author(s):  
Michaela Braun ◽  
Haley Wecker ◽  
Kara Dunmire ◽  
Caitlin Evans ◽  
Michael W. Sodak ◽  
...  
Keyword(s):  
Particle Size ◽  
Geometric Mean ◽  
Air Flow ◽  
Hole Diameter ◽  
Flow Index ◽  
Air Flow Rate ◽  
Screen Size ◽  
Flow Rates ◽  
Composite Flow ◽  
Ground Corn

This study was performed to evaluate hammermill tip speed, assistive airflow, and screen hole diameter on hammermill throughput and characteristics of ground corn. Corn was ground using two Andritz hammermills measuring 1 m in diameter each equipped with 72 hammers and 300 HP motors. Treatments were arranged in a 3 × 3 × 3 factorial design with three tip speeds (3774, 4975, and 6176 m/min), three screen hole diameters (2.3, 3.9, and 6.3 mm), and three air flow rates (1062, 1416, and 1770 fan revolutions per minute). Corn was ground on three separate days to create three replications and treatments were randomized within day. Samples were collected and analyzed for moisture, particle size, and flowability characteristics. There was a 3-way interaction (p = 0.029) for standard deviation (Sgw). There was a screen hole diameter × hammer tip speed interaction (p < 0.001) for geometric mean particle size dgw (p < 0.001) and composite flow index (CFI) (p < 0.001). When tip speed increased from 3774 to 6176 m/min, the rate of decrease in dgw was greater as screen hole diameter increased from 2.3 to 6.3 mm. For CFI, increasing tip speed decreased the CFI of ground corn when ground using the 3.9 and 6.3 mm screen. However, when grinding corn using the 2.3 mm screen, there was no evidence of difference in CFI when increasing tip speed. In conclusion, the air flow rate did not influence dgw of corn, but hammer tip speed and screen size were altered and achieved a range of dgw from 304 to 617 µm.

Effect of particle size on erosion measurements and predictions in annular flow for an elbow

Wear ◽  
2020 ◽  
pp. 203579
Author(s):  
G. Haider ◽  
M. Othayq ◽  
J. Zhang ◽  
R.E. Vieira ◽  
S.A. Shirazi
Keyword(s):  
Particle Size ◽  
Annular Flow ◽  
Effect Of Particle Size
Sign in / Sign up

Export Citation Format

Share Document