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Showing 1 to 20 of 22 for “"Bubbly flow"”.
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Experimental characterisation of bubbly flow using MRI
… imaging (MRI) towards the characterisation of bubbly flow systems. The principle goal of this study is to provide a hydrodynamic characterisation of a model bubble column using drift-flux analysis by supplying experimental closure for those parameters which are considered difficult to measure …
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Development of Advanced Image Processing Algorithms for Bubbly Flow Measurement
An accurate measurement of bubbly flow has a significant value for understanding the bubble behavior, heat and energy transfer pattern in different engineering systems. It also helps to advance the theoretical model development in two-phase flow study. Due to the interaction between the gas and …
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Performance measurements of a flashing flow nozzle
The performance of a flashing flow nozzle was quantified by efficiency and metastability measurements. Efficiency was calculated over a range of operating conditions, by using both inlet and exit conditions and the nozzle thrust. Metastability was quantified by a parameter that compared the …
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Improved turbulent lift momentum closure for multiphase computational fluid dynamics
… the lateral migration of the gas phase in bubbly flow, which strongly impacts the predictions of pressure drop and heat transfer [2]. Recent work from Sugrue has proposed an improved physical representation of the turbulent lift force utilizing a combination of direct numerical simulation …
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A robust momentum closure approach for multiphase computational fluid dynamics applications
… of these M-CFD methods in simulating two-phase flow and boiling heat transfer depends on their demonstrated accuracy and robustness, which signals a dual need for the comprehensive analysis of existing data and a reevaluation of the underlying physics. By virtue of the Eulerian-Eulerian …
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Modeling of Multicomponent Fuel Vaporization in Internal Combustion Engines
… the spray under flash boiling conditions with a bubbly-flow in the injector nozzle, and the effect of superheat degree on spray atomization was captured.
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Near-wall modeling of bubbly flows
… approach when applying M-CFD methods to the bubbly flow regime is to use an Eulerian-Eulerian two-fluid model, which solves for averaged mass and momentum equations for liquid and gas phases, as well as the k-epsilon turbulence model with modifications to account for the presence of bubbles. …
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Numerical simulation and modeling of two-phase flows using the volume-of-fluid method
Two-phase flows are of great interest in natural and industrial applications such as cavitation, spray atomization, and bubbly flows. As a two-phase system grows in complexity, analytical approximations of fluid behavior and experimental observations become more challenging. To make the detailed …
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A new experimental approach of characterizing two-phase flow and heat transfer in plate heat exchangers
Heat transfer of two-phase flow is not well characterized for plate heat exchangers (PHEs) despite their wide applications. No general correlations in the public domain are capable of accounting for all different effects of geometrical parameters, working fluids and operating conditions. The …
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CFD simulation of the dynamic flow behavior in a bubble column reactor
… is presented. This model is able to predict the bubbly flow parameter such as gas holdup, contact surface area, air volume fraction, pressure drop, and velocity magnitude to understanding the hydrodynamic flow behaviors. Three types of gas distributor design are tested on the 1.5 m height and …
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Traditional Image Processing and Modern Computer Vision Techniques for the Study of Two-Phase CO2 Flow
… which describe two-phase (gas-liquid) upwardly flowing CO2, for the purpose of using these parameters as sensor data for a control feedback loop, and for the automatic detection of flow regime transition, which is useful for the development of flow regime maps. The core focus of this thesis is …
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Development of a Fast X-ray Line Detector System for Two-Phase Flow Measurement
Measuring void fraction distribution in two-phase flow has been a challenging task for many decades because of its complex and fast-changing interfacial structure. In this study, a non-intrusive X-ray measurement system is developed and calibrated to mitigate this challenge. This approach has …
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Hydrodynamics and Mass Transfer in Bubble Columns
… the effect of column size and gas and liquid flow rates on column hydrodynamics and reactor performance. Among these approaches, phenomenological models based on either single-class or multi-class bubbles that were validated on cold flow systems have been successful in predicting the residence …
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Computational fluid dynamics and experimental study of the hydrodynamics of a bubble column and an air-water jet-stirred cell
A large number of flows encountered in nature and in many industrial processes areintrinsically multiphase flows. The efficiency and the effectiveness of multiphase flow processes strongly depend on the ability to model the fluid flow behaviour. Thus, a robust and accurate description of multiphase …
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Uncertainty Quantification and Accuracy Improvement of the Double-Sensor Conductivity Probe for Two-Phase Flow Measurement
… local time-averaged parameters in two-phase flows. The uncertainty of this measurement technique has not been well understood in the past as it involves many different steps and influential factors in a typical measurement. This dissertation aims to address this gap by performing a systematic …
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Studies in three phase gas-liquid-solid fluidised systems
… particle mixing and segregation, and phase flow dynamics (flow regime and circulation patterns). The studies have focused particularly on the solid behaviour and the influence of properties of solids present on the above parameters in three-phase, gas-liquid-solid fluidised systems …
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Performance measurement and visualization on the refrigerant distribution in the vertical manifold of the microchannel tube heat exchanger
… length and microchannel number. The inlet mass flow rate (min) and quality (x) are two main parameters affecting the distribution. The inlet quality was varied from 0.2 to 0.8, and the inlet mass flow rate was varied from 0.8 to 4.5 g/h per microchannel. For all three manifolds, the best …
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Development, Evaluation and Improvement of Correlations for Interphase Friction in Gas-Liquid Vertical Upflow
In this study, liquid-vapor vertical upflow has been research with the intent of finding an improved method of modelling the interphase friction in two-phase vertical flow in nuclear thermal-hydraulic codes. An improved method of modelling interphase friction should allow for better prediction of …
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The fundamentals of two-phase flow in wet domestic central heating systems
… is the installation of passive deaerators on the flow line of domestic wet central heating systems. To date, no data and theoretical models predicting the two-phase flow characteristics in domestic wet central heating systems are available in the open literature. This gap in literature has …
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Investigation into continuous spray and metered spray using compressed gas propellant
… the propellant into the valve stem to create ‘bubbly flow’ thus increasing the turbulence prior to the atomiser insert of the actuator. The domestic aerosol products are generally based on either spraying continuously (i.e. airfreshners, body spray, hairspray, insecticide, polish and …
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