Numerical study of blast mitigation effect of innovative barriers using woven wire mesh

2020 ◽  
Vol 213 ◽  
pp. 110574 ◽  
Author(s):  
Weifang Xiao ◽  
Matthias Andrae ◽  
Norbert Gebbeken
Author(s):  
Carolina C. Rodrigues ◽  
Henrique K. Eidt ◽  
Rafael Dunaiski ◽  
César Y. Ofuchi ◽  
Flávio Neves ◽  
...  

In the petroleum industry, during the production and transportation of oil, multiphase flow occurs, due to the usual mixture of the crude oil, water and gas. This type of flow can be simplified, for study purposes, as a two-phase one, in which the gas is one phase, and a mixture of oil and water is the other. Separation of gaseous and liquid phases at the wellhead level is done by a separator and has innumerous advantages, including avoiding or at least reducing typical problems of multiphase flows such as intermittent flow, severe slugging and hydrates deposition. Another advantage is to increase the efficiency of the submersible centrifugal pumps or other artificial lift process used. A recurrent problem found in exploration and production of oil and gas is the range of the fluid viscosities encountered during exploration and extraction of petroleum, which can greatly vary with the temperature or the composition of the oil being extracted. Thus, it is necessary to understand how this parameter affects the performance of the equipment used. In addition, installation and maintenance of separators are hampered by the large size of this type of equipment. Therefore, a prior distribution system is here proposed, aiming to distribute the flow in more than one branch, in order to decrease the general size of the separation equipment needed, while maintaining the flow rate and separation efficiency. This distribution system has a cyclonic chamber, in which the flow enters through two nozzles tangentially oriented with the wall of the chamber, which performs a pre-separation due to the centrifugal field, and divides the flow into four outlets. This work presents a numerical study on the height influence of the cyclonic chamber in a distribution system. The transient beginning of the flow is analyzed, with the stability of the film being study. This work is focused on the behavior of the liquid phase in this proposed distribution system, so that only single-phase liquid flow at the inlet of the distribution system is considered. A validation was done through comparison with experimental data obtained in a test rig, in which was used one wire mesh sensor with 12 wires in order to evaluate the thickness of the liquid film over time. In addition, different heights and viscosities are studied in order to evaluate their influence on the flow. The parameters investigated are the film thickness, velocity and turbulence kinetic energy fields and flow rates at the outlets, focusing on the stability of the film and the transient effects associated with the beginning of the flow. In order to perform this study, the commercial software ANSYS-CFX 15.0 was used, with a hybrid mesh, for four different heights and two inlet velocities.


2017 ◽  
Vol 165 ◽  
pp. 25-32 ◽  
Author(s):  
M.W. Baltussen ◽  
J.A.M. Kuipers ◽  
N.G. Deen
Keyword(s):  

Author(s):  
Ram Ranjan ◽  
Jayathi Y. Murthy ◽  
Suresh V. Garimella

A numerical model of the evaporating liquid meniscus under saturated vapor conditions in wick microstructures has been developed. Four different wick geometries representing the common wicks used in heat pipes, viz., wire mesh, rectangular grooves, sintered wicks and vertical microwires, are modeled and compared for evaporative performance. The solid-liquid combination considered is copper-water. Steady evaporation is modeled and the liquid-vapor interface shape is assumed to be static during evaporation. Liquid-vapor interface shapes in different geometries are obtained by solving the Young-Laplace equation using Surface Evolver. Mass, momentum and energy equations are solved numerically in the liquid domain, with the vapor assumed to be saturated. Evaporation at the interface is modeled by using appropriate heat and mass transfer rates obtained from kinetic theory. Thermo-capillary convection due to non-isothermal conditions at the interface is modeled for all geometries and its role in heat transfer enhancement from the interface is quantified for both low and high superheats. More than 80% of the evaporation heat transfer is noted to occur from the thin-film region of the liquid meniscus. Very small Capillary and Weber numbers arising due to small fluid velocities near the interface for low superheats validate the assumption of static liquid meniscus shape during evaporation. Solid-liquid contact angle, wick porosity, solid-vapor superheat and liquid level in the wick pore are varied to study their effects on evaporation from the liquid meniscus.


2014 ◽  
Vol 67 (1-2) ◽  
pp. 214-222 ◽  
Author(s):  
R. Kouhikamali ◽  
S.M.A. Noori Rahim Abadi ◽  
M. Hassani

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Sebastian Stanisławek ◽  
Andrzej Morka

This paper presents a 2D numerical study of v-shape deflectors subjected to high explosive charge detonation. The literature provides many papers concerning the appropriate geometry of blast protection deflectors. Such structures require a relatively high distance between the ground and the vehicle chassis. In most cases, the placement of a deflector is not possible or it cannot cover the whole area under a chassis. An interesting question that arises is to what extent a set of small deflectors would be able to mitigate blast effects. The content of this paper constitutes an answer to this question. Three analyses were conducted: (1) multiplication of triangle components, (2) effect of deflector size, and (3) geometry-induced shock dynamics. The problem was solved with the use of modelling and simulation methods, in particular, CFD-FEM implemented in the LS-DYNA code. It was considered a plain issue in computational fluid dynamics, where space discretization for each option was built with two-dimensional elements to ensure efficient calculations. Deflectors were described using a rigid wall boundary condition, and an adequate simplified detonation model was assumed. The primary measure of the results was reaction force history, with momentum transfer and pressure distribution maps considered supplementary. The studies performed showed that both minimizing the v-shape deflector size and surrounding it with adjacent structures had a negative impact on its blast mitigation effectiveness. However, for each multi-v-shape deflector, some improvement was present, and, therefore, in situations where the installation of a typical protector is not possible due to dimensional requirements, it may offer a compromise solution.


Fibers ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 64 ◽  
Author(s):  
Giuseppe Tiberti ◽  
Antonio Mudadu ◽  
Bryan Barragan ◽  
Giovanni Plizzari

Industrial pavements are thin slabs on a continuous support subjected to restrained shrinkage and loads. The use of fibers as an alternative reinforcement to steel welded wire mesh and rebars is today an extensive practice for the reinforcement of concrete slabs-on-grade. Despite the widespread use of fiber reinforcement, the corresponding benefits in controlling cracking phenomena due to shrinkage are generally not considered in the design process of Fiber Reinforced Concrete (FRC) slabs-on-grade. The post-cracking performance provided by glass macro-fibers at low crack openings is particularly convenient in structures with a high degree of redundancy. Referring to service conditions, it is well known that concrete shrinkage as well as thermal effects tend to be the principal reasons for the initial crack formation in slabs-on-grade. A numerical study on the risk of cracking due to shrinkage in ground-supported slabs is presented herein. Special attention is devoted to the evaluation of the beneficial effects of glass fibers in controlling cracking phenomena due to shrinkage. The numerical analyses are carried out on jointless pavements of different sizes. Since shrinkage stresses in slabs-on-grade are considerably influenced by external constraints which limit the contractions, different subgrade conditions have been also considered.


Structures ◽  
2019 ◽  
Vol 20 ◽  
pp. 581-593 ◽  
Author(s):  
Zhejian Li ◽  
Wensu Chen ◽  
Hong Hao

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