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Showing 1 to 16 of 16 for “"Downcomer"”.
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Modeling Two-Phase Flow in the Downcomer of a Once-Through Steam Generator using RELAP5/MOD2
… study is to develop an accurate model of the downcomer of the once-through steam generator (OTSG) developed by Babcock & Wilcox, using RELAP5/MOD2. While the physical model can be easily developed, several parameters are left to be adjusted to optimally model the downcomer and match data that …
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Numerical Simulation of Liquid-Solid Circulating Fluidized Beds
… A typical LSCFB is comprised of a riser, a downcomer, a liquid-solid separator, a top solids-return pipe and a bottom solids-return pipe. In light of the literature review conducted in this research, a detailed modeling of the protein extraction using an LSCFB ion-exchange system requires a …
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CFD Analysis of Aspirator Region in a B&W Enhanced Once-Through Steam Generator
… generator level calculations, steam generator downcomer models, and flow induced vibration analyses. The OpenFOAM CFD software package was used to develop the three-dimensional model of the EOTSG aspirator region, perform the calculations, and post-process the results. Through a series of …
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CFD Modeling and Simulation of Natural Circulation in Helium- Cooled Very High Temperature Reactors
… flow loop with four riser and four downcomer tubes, each equipped with heating coils, thermocouples, and pressure sensors. Natural circulation is driven by density gradients induced by asymmetric heating of the riser and downcomer tubes, simulating decay heat removal during LOFC …
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Flooding and non-equilibrium in counter-current flows with reference to pressurised water reactors
… on two-1/10 scale planar test sections of a PWR downcomer annulus. The experiments involved the countercurrent flows of air and water and the data were compared with existing flooding correlations for tubes. The comparison revealed the inadequacy of the existing correlations. In the Phase 1 test …
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Effect of liquid flow patterns on distillation trays
… the flow separated at the ends of the inlet downcomer. This caused liquid to flow straight across the tray between the downcomers and large circulating regions to be formed in the side regions of the tray. The effect of the air crossflow on the flow pattern was then observed on a sieve tray …
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Sieve plate distillation dynamics
… liquid composition on the plate near the exit downcomer. The resulting frequency response was relatively flat in the frequency region of primary interest. The flatness of the frequency response was attributed to poor liquid mixing on tha plates. Based on the experimental observations, a plate …
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Plenum-to-plenum heat transfer characteristics under natural circulation in a scaled-down prismatic modular reactor
… transfer test facility with one riser and one downcomer between two plena to investigate loss of flow accident scenario (LOFA) for a prismatic very high temperature reactor (VHTR). Using advanced heat transfer coefficient probe and T-thermocouples. The facility represents a scaled down …
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Hypolimnetic Aerators: Predicting Oxygen Transfer and Water Flow Rate
… system ranged from 2.7-3.9 mm. The riser and downcomer DO profiles and gas holdups predicted by the model are in close agreement with experimental results. The water flow rate model was fitted to the experimental water velocity by varying the frictional loss coefficient for the air-water …
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Numerical Modeling of Air-Water Flows in Bubble Columns and Airlift Reactors
… of the gas flow due to recirculation from the downcomer and connectors, whereas the bubble column oscillations were random and resulted in gas flow through the center of the column. The profiles of gas holdup, gas velocity, and liquid velocity showed that the airlift reactor flow was asymmetric …
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Development of a photobioreactor for the cultivation of the freshwater microalga Haematococcus pluvialis
… of three windings. They also had a riser and downcomer of increased length when compared to TBRI and TBR2. This increased the bulk density difference between these stages and resulted in an increased fluid flow rate and consequently improved turbulence within the photostage. As well as being …
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Flow patterns on sieve trays
… separation occurred at the ends of the inlet downcomer which produced large circulating zones along the tray segments both on the non-perforated and perforated trays. The air when forced through the liquid, inhibited circulating flow such that it only occurred at high water inlet velocities. …
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A study of liquid-liquid extraction in a sieve plate column
… plate designs, and variable plate spacing and downcomer heights, and the system used was Clairsol `350' (dispersed) - acetone - deionised water (continuous) with either direction of mass transfer. Drop size distributions were best described by the functions proposed by Gal-or, and then …
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Flow patterns on distillation trays
… the flow separated at the ends of the inlet downcomer and circulations of up to 30% of the tray area were observed. Water-cooling and the manometer measurements were used to show the effect of the flow pattern on the tray efficiency and the height of clear liquid respectively. The efficiency …
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Computational Modeling and Simulations of Hydrodynamics for Air-Water External Loop Airlift Reactors
… predicted the formation of the gas bubble in the downcomer. The 3D PBM simulations also gave better predictions for the average bubble diameter size in the riser. It was concluded that a two-dimensional domain is adequate for gas-liquid flow simulations of a simple bubble column geometry, whereas …
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The use of flow control devices to improve the flow pattern and throughput of sieve trays
… liquid measurements across the tray and in the downcomer using manometers. This work presents experiments designed to evaluate flow control devices proposed to improve the gas liquid interaction and hence improve the tray efficiency and throughput. These are (a) the use of intermediate weirs to …