The distribution of solid particles suspended in a turbulent flow: A stochastic approach

1991 ◽  
Vol 7 (2) ◽  
pp. 123-130
Author(s):  
Shao Xuejun ◽  
Xia Zhenhuan
Keyword(s):  
Turbulent Flow ◽  
Stochastic Approach ◽  
Solid Particles

LIMITATIONS OF THE STOCHASTIC APPROACH IN TWO-PHASE TURBULENT FLOW CALCULATIONS

1996 ◽  
Vol 6 (2) ◽  
pp. 211-225 ◽  
Author(s):  
Keh-Chin Chang ◽  
Wen-Jing Wu ◽  
Muh-Rong Wang
Keyword(s):  
Turbulent Flow ◽  
Stochastic Approach ◽  
Two Phase

scholarly journals Heterogeneous freezing of water droplets containing kaolinite particles

2011 ◽  
Vol 11 (9) ◽  
pp. 4191-4207 ◽  
Author(s):  
B. J. Murray ◽  
S. L. Broadley ◽  
T. W. Wilson ◽  
J. D. Atkinson ◽  
R. H. Wills
Keyword(s):  
Cooling Rate ◽  
Surface Area ◽  
Clay Mineral ◽  
Constant Temperature ◽  
Hydrophobic Surface ◽  
Supercooled Liquid ◽  
Stochastic Approach ◽  
Solid Particles ◽  
Rate Coefficients ◽  
Water Droplets

Abstract. Clouds composed of both ice particles and supercooled liquid water droplets exist at temperatures above ~236 K. These mixed phase clouds, which strongly impact climate, are very sensitive to the presence of solid particles that can catalyse freezing. In this paper we describe experiments to determine the conditions at which the clay mineral kaolinite nucleates ice when immersed within water droplets. These are the first immersion mode experiments in which the ice nucleating ability of kaolinite has been determined as a function of clay surface area, cooling rate and also at constant temperatures. Water droplets containing a known amount of clay mineral were supported on a hydrophobic surface and cooled at rates of between 0.8 and 10 K min−1 or held at constant sub-zero temperatures. The time and temperature at which individual 10–50 μm diameter droplets froze were determined by optical microscopy. For a cooling rate of 10 K min−1, the median nucleation temperature of 10–40 μm diameter droplets increased from close to the homogeneous nucleation limit (236 K) to 240.8 ± 0.6 K as the concentration of kaolinite in the droplets was increased from 0.005 wt% to 1 wt%. This data shows that the probability of freezing scales with surface area of the kaolinite inclusions. We also show that at a constant temperature the number of liquid droplets decreases exponentially as they freeze over time. The constant cooling rate experiments are consistent with the stochastic, singular and modified singular descriptions of heterogeneous nucleation; however, freezing during cooling and at constant temperature can be reconciled best with the stochastic approach. We report temperature dependent nucleation rate coefficients (nucleation events per unit time per unit area) for kaolinite and present a general parameterisation for immersion nucleation which may be suitable for cloud modelling once nucleation by other important ice nucleating species is quantified in the future.

Sedimentation of solid particles in turbulent flow in horizontal channels

2004 ◽  
Vol 140 (1-2) ◽  
pp. 79-85 ◽  
Author(s):  
Ayse Sarimeseli ◽  
Gudret Kelbaliyev
Keyword(s):  
Turbulent Flow ◽  
Solid Particles

scholarly journals SENSIBILIDADE DE GOTEJADORES À OBSTRUÇÃO POR PARTÍCULAS DE AREIA

Irriga ◽  
2018 ◽  
Vol 23 (2) ◽  
pp. 194-203
Author(s):  
Acácio Perboni ◽  
José Antonio Frizzone ◽  
Rubens Duarte Coelho ◽  
Rogério Lavanholi ◽  
Ezequiel Saretta
Keyword(s):  
Turbulent Flow ◽  
Flow Rate ◽  
Flow Regimes ◽  
Solid Particles ◽  
Automated System ◽  
Particle Sizes ◽  
Initial Flow ◽  
Water Flow Velocity ◽  
Sand Particles ◽  
Micro Irrigation

SENSIBILIDADE DE GOTEJADORES À OBSTRUÇÃO POR PARTÍCULAS DE AREIA     ACÁCIO PERBONI1; JOSÉ ANTONIO FRIZZONE2; RUBENS DUARTE COELHO2; ROGÉRIO LAVANHOLI3 E EZEQUIEL SARETTA4   1 Professor, IFMT, Campo Novo do Parecis - MT, [email protected] 2 Professor, Departamento de Engenharia de Biossistemas, ESALQ/USP, Piracicaba - SP, [email protected]; [email protected] 3 Doutorando, Departamento de Engenharia de Biossistemas, ESALQ/USP, Piracicaba - SP, [email protected] 4 Professor, UFSM, Cachoeira do Sul - RS, [email protected]     1 RESUMO   O objetivo deste trabalho foi avaliar a influência do tamanho e concentração de partículas de areia e da velocidade de fluxo da água nas linhas na sensibilidade à obstrução de um modelo de gotejador do tipo cilíndrico, não regulado, com vazão nominal de 2 L h-1. Foram realizados ensaios de obstrução com areia misturada em água destilada, combinando os seguintes fatores: três faixas granulométricas de partículas de areia, três concentrações de areia e três velocidades de fluxo de água no tubo. A vazão de 32 gotejadores foi medida a cada doze minutos por meio de um sistema automatizado. Nos ensaios com faixa granulométrica de 0,105 a 0,25 mm, ocorreu a obstrução nas concentrações de 250 e 500 mg L-1, para os regimes de escoamento de transição e turbulento. Já na faixa granulométrica de 0,25 a 0,5 mm, ocorreu obstrução nas concentrações de 100, 250 e 500 mg L-1, para os regimes de escoamento de transição e turbulento. A obstrução de gotejadores ocorreu de forma aleatória nas oito linhas. Após obstruídos os gotejadores não desobstruíram com o passar do tempo de ensaio.   Palavras-chave: microirrigação, partículas sólidas inertes, granulometria, concentração     PERBONI, A.; FRIZZONE, J. A.; COELHO, R. D.; LAVANHOLI, R.; SARETTA, E. SENSITIVITY OF DRIPPERS TO CLOGGING CAUSED BY SAND PARTICLES     2 ABSTRACT   The purpose of this research was to assess the influence of concentration and size of sand particles, and water flow velocity in laterals on the sensitivity of drippers to clogging. A cylindrical integrated non-pressure compensating dripper of 2 L h-1 nominal flow rate was used. Experiments were undertaken using distilled water and sand particles, according to the following levels: (a) three ranges of particles sizes; (b) three concentrations of particles; and, (c) three flow velocities in the laterals. The flow rate of 32 drippers was measured at every 12 minutes by an automated system. Within the range of particle sizes from 0.105 to 0.25 mm, clogging of emitters was observed under transient and turbulent flow regimes, and under particles concentration of 250 and 500 mg L-1. Within the range of particles sizes from 0.25 to 0.5 mm, clogging was observed for all concentrations under transient and turbulent flow regimes. Clogging of emitters occurred as a random phenomenon. Once clogged, emitters did not recover their initial flow rate.    Keywords: micro irrigation, inert solid particles, particle size, concentration

The mixing of solid particles in a motionless mixer—a stochastic approach

AIChE Journal ◽  
1972 ◽  
Vol 18 (5) ◽  
pp. 984-989 ◽  
Author(s):  
S. J. Chen ◽  
L. T. Fan ◽  
C. A. Watson
Keyword(s):  
Stochastic Approach ◽  
Solid Particles ◽  
Motionless Mixer

Modeling of the Size Distribution Resulting from Dissolution of Spherical Solid Particles in Turbulent Flow

2012 ◽  
Vol 33 (4) ◽  
pp. 521-526 ◽  
Author(s):  
Ahmet Ekmekyapar ◽  
Asım Künkül ◽  
Mehmet Yüceer ◽  
Gudret Kelbaliyev
Keyword(s):  
Turbulent Flow ◽  
Size Distribution ◽  
Solid Particles
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