scholarly journals A Numerical Analysis Research on Earlier Behavior of Molten Droplet Covered with Vapor Film at the Stage of Triggering and Propagation in Steam Explosion

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Mingjun Zhong ◽  
Yankai Li ◽  
Meng Lin ◽  
Minghao Yuan ◽  
Yanhua Yang
Keyword(s):  
Pressure Pulse ◽  
Experimental Studies ◽  
Hydrodynamic Effect ◽  
Vapor Film ◽  
Droplet Deformation ◽  
Molten Droplet ◽  
Material Density ◽  
Liquid Systems ◽  
Droplet Behavior ◽  
Very High

When the molten fuel with high temperature falls into the cavity water, it will be dispersed into droplets which are covered with vapor films due to the rapid heat transfer with phase transition. This situation cannot be simply described by liquid-liquid or gas-liquid systems. And there are no sufficient experimental studies on the behavior of droplet covered with vapor film because of the rapid reaction and the difficulty in capture of the film configuration. In this paper, a multiphase code with the volume of fluid (VOF) method is used to simulate the earlier behavior of droplet when vapor film exits. The earlier behavior is defined as behavior of the droplet before its disintegration. Thermal effect and pure hydrodynamic effect are, respectively, considered. The simulation results indicate that the film thickness and material density have significant effect on the earlier behavior of droplet. The situation assumed in Ciccarelli and Frost’s model (1994) is observed in current simulation of earlier thermal droplet behavior. The effect of triggering pressure pulse on earlier hydrodynamic behavior is also discussed and it indicates that vapor film has little effect on the hydrodynamic droplet deformation when the intensity of the pressure pulse is very high.

Numerical Simulation of Thermal Behavior of a Molten Droplet Covered With Vapor Film

2014 ◽  
Author(s):  
Mingjun Zhong ◽  
Meng Lin ◽  
Jinbiao Xiong ◽  
Yankai Li ◽  
Yanhua Yang
Keyword(s):  
Experimental Studies ◽  
Vapor Film ◽  
Volume Of Fluid Method ◽  
Molten Droplet ◽  
Material Density ◽  
Phase Code ◽  
Liquid Systems ◽  
Droplet Behavior ◽  
Simulation Results ◽  
Multi Phase

When the molten fuel with high temperature falls into the cavity water, it will be dispersed to droplets which are covered with vapor films due to the rapid heat transfer with phase transition. This situation cannot be simply described by liquid-liquid nor gas-liquid systems. And there are not sufficient experimental studies on the behavior of droplet covered with vapor film because of the rapid reaction and the difficulty in capture of the film configuration. In this paper, A multi-phase code with the Volume of Fluid Method (VOF) is developed to simulate the behavior of droplet covered with vapor film. Thermal effect is considered. The simulation results indicate that the film thickness and material density have significant effect on the behavior of droplet. The situation assumed in Ciccarelli and Frost’s model is observed in current simulation of thermal droplet behavior.

Application of Hybrid Biosystems for Stimulation of Oil Production

2021 ◽  
Author(s):  
Baghir Alakbar Suleimanov ◽  
Sabina Jahangir Rzayeva ◽  
Ulviyya Tahir Akhmedova
Keyword(s):  
Oil Recovery ◽  
Single Phase ◽  
Experimental Studies ◽  
Oil Production ◽  
Pore Channel ◽  
Subcritical Region ◽  
Slippage Effect ◽  
Liquid Systems ◽  
Reservoir Conditions

Abstract Microbial enhanced oil recovery is considered to be one of the most promising methods of stimulating formation, contributing to a higher level of oil production from long-term fields. The injection of bioreagents into a reservoir results in the creation of oil-dicing agents along with significant amount of gases, mainly carbon dioxide. In early, the authors failed to study the preparation of self-gasified biosystems and the implementation of the subcritical region (SR) under reservoir conditions. Gasified systems in the subcritical phase have better oil-displacing properties than non-gasified systems. The slippage effect determines the behavior of gas–liquid systems in the SR under reservoir conditions. Slippage occurs more easily when the pore channel has a smaller average radius. Therefore, in a heterogeneous porous medium, the filtration profile of gasified liquids in the SR should be more uniform than for a degassed liquid. The theoretical and practical foundations for the preparation of single-phase self-gasified biosystems and the implementation of the SR under reservoir conditions have been developedSR under reservoir conditions. Based on experimental studies, the superior efficiency of oil displacement by gasified biosystems compared with degassed ones has been demonstrated. The possibility of efficient use of gasified hybrid biopolymer systems has been shown.

scholarly journals Computational Approaches for Studying Slag–Matte Interactions in the Flash Smelting Furnace (FSF) Settler

Processes ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 485
Author(s):  
Jani-Petteri Jylhä ◽  
Nadir Ali Khan ◽  
Ari Jokilaakso
Keyword(s):  
Flash Smelting ◽  
Copper Production ◽  
Limiting Factor ◽  
Molten Droplet ◽  
Geometry Modeling ◽  
Droplet Behavior ◽  
Flow Phenomena ◽  
Modeling Software ◽  
Flash Smelting Furnace ◽  
Physical Phenomena

Computational methods have become reliable tools in many disciplines for research and industrial design. There are, however, an ever-increasing number of details waiting to be included in the models and software, including, e.g., chemical reactions and many physical phenomena, such as particle and droplet behavior and their interactions. The dominant method for copper production, flash smelting, has been extensively investigated, but the settler part of the furnace containing molten high temperature melts termed slag and matte, still lacks a computational modeling tool. In this paper, two commercial modeling software programs have been used for simulating slag–matte interactions in the settler, the target being first to develop a robust computational fluid dynamics (CFD) model and, second, to apply a new approach for molten droplet behavior in a continuum. The latter is based on CFD coupled with the discrete element method (DEM), which was originally developed for modeling solid particle–particle interactions and movement, and is applied here for individual droplets for the first time. The results suggest distinct settling flow phenomena and the significance of droplet coalescence for settling velocity and efficiency. The computing capacity requirement for both approaches is the main limiting factor preventing full-scale geometry modeling with detailed droplet interactions.

Numerical study on structures formed by the deposition and solidification of a single molten droplet

2020 ◽  
Vol 98 (10) ◽  
pp. 907-916
Author(s):  
Wenbin Li ◽  
Ying Zhang ◽  
Yue Chen ◽  
Peisheng Li ◽  
Chunhong Ma
Keyword(s):  
Cooling Rate ◽  
Numerical Study ◽  
Deposition Process ◽  
Droplet Deformation ◽  
Molten Droplet ◽  
Front Tracking Method ◽  
Parametric Studies ◽  
Dynamic Metrics ◽  
Formed Structure

The formed structure is of importance in determining the surface quality of a component made by droplet-based 3D printing. In the present work, the molten droplet solicitation process was simulated under an axisymmetric system where the smallest length scale and time scale were fully resolved. Evolutions of sharp droplet interfaces were captured through the front tracking method. Parametric studies have been carried out to explore how the dynamic metrics, which include the Ohnesorge number (Oh) and Weber number (We), can affect the structure of depositing droplet. The effect of the superheat parameter on the cooling rate was also investigated in the final section. Numerical results show that the inertial resisting force is critical dynamics in the variation of horizontal dimensionless length at the early deposition process. Three levels of Oh numbers and stages of We numbers were classified according to the deformation behavior. Flattening degree under different Oh number and We number cases were both fitted well by the exponential function. This paper also reveals that the variation law of the cooling rate and solidification time is affected by the superheat parameter, resulting in a feasible and promising method to predict droplet deformation time through the fully resolved numerical simulations during the manufacturing process.

Experimental Studies on Galling Onset in OCTG Connections: A Review

Tribology ◽  
2006 ◽  
Author(s):  
S. Ekwaro-Osire ◽  
F. Karpat
Keyword(s):  
Natural Gas ◽  
Experimental Studies ◽  
Oil Industry ◽  
Superior Performance ◽  
Review Of Literature ◽  
Performance Properties ◽  
Operational Costs ◽  
Concise Review ◽  
Mode Of Failure ◽  
Very High

With today's high prices for natural gas and oil, the demand for oil and country tubular goods (OCTG), with superior performance properties, is very high. Failures in OCTG can be attributed to numerous sources, for example, makeup torque, corrosion, and galling. Thread galling is the most common mode of failure. This failure often leads to leakage, corrosion of the material, and loss of mechanical integrity. The failure of OCTG eventually amounts to excessive operational costs for the gas and oil industry. The have been numerous approaches taken to improve the galling resistance of OCTG connections. The advocacy of these approaches is often achieved through experimental studies using galling testers. In this paper, it is proposed to classify the galling testers in seven distinct groups. There is a need to design and use effective galling testers to understand and improve the performance of OCTG connections. Thus, the objective of this paper was to present a concise review of literature related to the galling testers that may have applications to OCTG.

scholarly journals The Pathophysiology of Post-Traumatic Glioma

2018 ◽  
Vol 19 (8) ◽  
pp. 2445 ◽  
Author(s):  
Donata Simińska ◽  
Klaudyna Kojder ◽  
Dariusz Jeżewski ◽  
Ireneusz Kojder ◽  
Marta Skórka ◽  
...  
Keyword(s):  
Brain Tumor ◽  
Immune System ◽  
Experimental Studies ◽  
Epidemiological Studies ◽  
Detection Rates ◽  
Expression Of Genes ◽  
Specific Morphology ◽  
Post Traumatic ◽  
The Brain ◽  
Very High

Malignant glioma is a brain tumor with a very high mortality rate resulting from the specific morphology of its infiltrative growth and poor early detection rates. The causes of one of its very specific types, i.e., post-traumatic glioma, have been discussed for many years, with some studies providing evidence for mechanisms where the reaction to an injury may in some cases lead to the onset of carcinogenesis in the brain. In this review of the available literature, we discuss the consequences of breaking the blood–brain barrier and consequences of the influx of immune-system cells to the site of injury. We also analyze the influence of inflammatory mediators on the expression of genes controlling the process of apoptosis and the effect of chemical mutagenic factors on glial cells in the brain. We present the results of experimental studies indicating a relationship between injury and glioma development. However, epidemiological studies on post-traumatic glioma, of which only a few confirm the conclusions of experimental research, indicate that any potential relationship between injury and glioma, if any, is indirect.

Visual Observation of Vapor Film Collapse Behavior During Vapor Explosion

2002 ◽  
Author(s):  
Yutaka Abe ◽  
Hideki Nariai
Keyword(s):  
High Temperature ◽  
Pressure Pulse ◽  
Film Surface ◽  
Vapor Film ◽  
Visual Data ◽  
Vapor Explosion ◽  
Auto Correlation ◽  
Piv Technique ◽  
Collapse Behavior ◽  
Film Collapse

During severe accident of a light water reactor, various thermal hydraulic phenomena including vapor explosion could threaten the integrity of the containment vessel. Thermal detonation model is proposed to describe the vapor explosion. According to the model, several processes should be sequentially satisfied for the trigger phenomena of the vapor explosion. One of the most important processes for the trigger phenomena is the vapor film collapse around high temperature molten material droplets. In the present study, the vapor film collapse behavior around high temperature solid particle submerged into water was experimentally investigated by attacking a pressure pulse to the vapor film on a high temperature sold particle. The interfacial phenomena between vapor and water were measure by using a high-speed video camera of the maximum speed of 40,500 fps. The visual data obtained were processed with visual data processing techniques. That is, the average vapor film thickness was estimated, dynamic behaviors of the interfaces were analyzed with PIV technique and the interface movement was estimated with the digital auto correlation techniques from the visual data obtained. Furthermore, the transients of the temperature and pressure were simultaneously measured. The interfacial temperatures between vapor and water, and between molted liquid and water are analytically estimated by solving the heat conduction equation with the data obtained as the boundary conditions. It is clarified that vapor collapse by pressure pulse occurs homogeneously around the vapor film surface on a high temperature particle. Microscopic information are obtained from the visual data by using visual data processing technique, PIV technique and digital auto-correlation technique. At the time the vapor film surface changes to white, the saturation temperature exceeds the interfacial temperature. The microscopic vapor film collapse behavior indicates the possibility of the phase change at the vapor film collapse.

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