flow modeling Articles
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Requirements for transport network flow models used in reliability analysis
The network reliability of transport systems has been intensively studied in the last two decades. When we discuss network reliability models, the following four categories of topics can be identified: routing and scheduling under uncertain conditions; flow models for degraded and congested networks; evaluation and measurement of reliability; network design and management. Of these, transport ...
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Compositional fluid tracking: an optimised approach to subsea fluid sampling
The complex challenges and cost of intervention in acquiring representative subsea fluid sampling has necessitated an optimised novel approach to compositional fluid tracking to improve estimation of the local fluid properties for facility design optimisation and operations of subsea production systems. This enables computation of the local thermodynamic and hydrodynamic equilibrium in a ...
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The influence of ejector component efficiencies on performance of Ejector Expander Refrigeration Cycle and exergy analysis
In order to identify the amounts and locations of irreversibility within the components of the cycle, exergy analysis is employed. A two-phase constant area ejector flow model was used. As the ejector component efficiencies increase, coefficient of performance and exergy efficiency increase. As a result, when the efficiencies of motive nozzle and diffuser are 100%, the efficiency of ejector ...
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Entropy generation for unsteady natural convection and radiation within a tilted saturated porous channel
The problem of entropy generation for unsteady natural convection and radiation in a tilted open-ended channel, submitted to uniform hot walls temperature and filled with an isotropic fluid saturated porous medium is outlined. The present study is carried out using the Darcy flow model. The local thermal equilibrium assumption is assumed. Viscous dissipation effects are taken into account. The ...
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Vent Flows in Fire Compartments with Large Openings
The Kawagoe vent flow model has been widely used to study fully developed compartment fires. It is well known that the Kawagoe model is only adequate for compartments with relatively small openings because it overestimates the vent flow rates for compartments with large openings. For a compartment with a very wide opening occupying a large fraction of one wall, experimental observations show that ...
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Exergy analysis of Airlift Systems: experimental approach
Airlift Systems (ALS) are widely used in various industrial applications. As the main part of the flow through ALS's upriser pipe, is formed by gas-liquid flow, the analysis of such systems will be accompanied by problems of two-phase flow modelling. Several effective variables are involved in ALS; thereupon comprehensive method is needed to consider these parameters. Exergy analysis can be ...
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A flood lamination strategy based on transportation network with time delay
Over the last few years, the frequency and intensity of floods has become more marked due to the influence of climate change. The engendered problems are related to the safety of goods and persons. These considerations require predictive management that will limit water height downstream. In the literature, numerous works have described flow modeling and management. The work presented in this ...
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A simple explicit model approximating the relationship between speed and density of vehicular traffic on urban roads
With the increase in simulation of urban environments for the purpose of planning, modelling vehicular traffic has become important. Since empirical evidence on traffic flow is relatively sparse, models are being increasingly used for planning urban roads and environments. In this paper, a simple, explicit model is proposed to approximate the speed versus density of vehicular traffic flow. The ...
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Considering line status in the dispatch process to minimise transmission congestion cost and maximise system usage
In competitive electricity markets, energy locational marginal prices (LMPs) are commonly used to allocate energy payments and transmission congestion charges and credits. In these markets, energy prices and transmission pricing are highly affected by transmission constraints, where a congested transmission is accompanied by congestion costs, lower system utilisation, and higher energy prices due ...
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Wresting informational privacy from free speech
This paper deals with the conflict between privacy rights and freedom of speech. Courts have upheld freedom of speech to the detriment of the privacy interest. Even when the information is false, courts have been reluctant to allow restrictions on the collection and dissemination of personal information. To establish a stronger case for privacy, we concentrate on a special type of privacy: ...
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Resilience-based failure mode effects and criticality analysis for regional water supply system
An alternative risk assessment method, known as failure mode effects and criticality analysis (FMECA), is demonstrated on the regional water supply systems (RWSS) in Tucson, AZ, USA that combines delivery of potable and reclaimed water and conveyance of wastewater to a developing area within the Tucson RWSS. The goal of FMECA is to examine the volumetric severity of a component failure on the ...
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Multi-objective optimisation of cost–benefit of urban flood management using a 1D2D coupled model
This paper presents a multi-objective optimisation (MOO) tool for urban drainage management that is based on a 1D2D coupled model of SWMM5 (1D sub-surface flow model) and BreZo (2D surface flow model). This coupled model is linked with NSGA-II, which is an Evolutionary Algorithm-based optimiser. Previously the combination of a surface/sub-surface flow model and evolutionary optimisation has been ...
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Transient stability and power flow model of the unified power flow controller for various control strategies
This paper describes and validates transient stability and power flow model of a Unified Power Flow Controller (UPFC), and presents a detailed comparison of different controls strategies, proposing novel, efficient, and simple controls for this controller. The proposed model accurately represents the behaviour of the controller in quasi-steady state operating conditions, and hence is adequate for ...
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Validation of a mass consistent flow model as part of a decision support system
In the context of real time (online) decision support systems for nuclear installations, atmospheric dispersion and deposition has to be calculated for a mesoscale area. Typically, the wind field in this area is influenced by topography. Therefore, simple Gaussian type modelling is not appropriate. Initiated and funded by the Bundesamt fur Strahlenschutz, simple (diagnostic mass consistent) flow ...
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A model and a simulator for disaster recovery
The level of economic and social cost arising from large scale disasters has become apparent in recent years. One of the conclusions that can be drawn from recent experiences is that both corporations and regulators have difficulty in predicting both the post disaster scenario, and the results of management actions in these scenarios. This paper discusses an approach that could lead to ...
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A CFD study of the effect of venturi geometry on high pressure wet gas metering
Venturi meter is increasingly being preferred as wet gas flow meter because of its simple construction and ease of operation. It has been found that the performance of venturi in single phase gas is very different from that of water. In this work, with a view to optimise the design, the effects of diameter, diameter ratio and convergent angle on the performance of a venturi meter for wet gas ...
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8` SlurryFlo Control Valve - Case Study
We then introduced a SlurryFlo control valve into the 3D model, with identical piping layout, downstream knife gate valve and flow parameters (see Fig 2). A side-by-side comparison of the two flow models depicts very different scenarios; SlurryFlo’s patented trim design acts as variable orifice, centering the abrasive froth slurry within the ...
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Impact of pumping in open pit mining on groundwater flow: a case study
The groundwater flow behaviour was analysed during pre-monsoon, monsoon, and post-monsoon seasons. At first, the groundwater model was analysed in the steady state, and then the same was applied in the transient state to predict the spatio-temporal behaviour of groundwater in the region. Transient flow model was also developed to estimate the potential impact of pumping of groundwater due to ...
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Flow modeling and analysis of compound channel in river network with complex floodplains and groynes
Presented here are flow simulations of a network of natural rivers flanked by one or two large and complex floodplains with impermeable groynes and bridge embankments using one- and quasi-two-dimensional dynamic flow models. The effects of the large floodplain storage capacity, momentum transfer interaction and apparent shear stress at the vertical interface between the main channel and ...
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On the influence of sea-surface temperature on mesoscale flows: an example from the city of Athens
The differences resulting in mesoscale flow estimations when using constant or varying (in time and space) sea-surface temperature information have been investigated, with the aid of appropriate air-flow simulations. Results suggest interesting interactions of land and sea surfaces with the atmosphere, which are expected to influence atmospheric flow modelling and air quality management in ...
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