Spatial Distribution Of Liquid Research Articles

An approach to separation efficiency modelling of structured packings based on X-ray tomography measurements: Application to aqueous viscous systems

The objective of this work is the development of a model to predict the separation efficiency of structured packings for aqueous viscous systems. The modelling approach is based on a hydrodynamic analogy between the real complex flow patterns and simplified fluid dynamic elements. Understanding of dominating liquid flow patterns inside structured packing is essential for the model development. Therefore, in this work, X-ray tomography is used to investigate liquid flow morphology. To study the influence of viscosity, water and water/glycerine mixtures are employed as working liquids.X-ray tomography permits the spatial distribution of liquid in the cross-section of a column filled with MellapakPlus 752.Y packing elements to be determined. The resulting images are used to evaluate liquid hold-up and gas-liquid interfacial area. Furthermore, liquid flow patterns (film flow, contact-point liquid, flooded regions) are identified, and their contribution to the overall hold-up is determined in dependence on flow rate and liquid viscosity.The results of the liquid flow morphology analysis help to develop a hydrodynamic analogy model. To implement the gas-liquid contact area and the flooded regions into this model, the packing is represented as a bundle of dry, filled and irrigated cylindrical channels, while the ratio between different channel types is determined from the analysis of tomographic images. This simplified hydrodynamic description allows a direct application of rigorous partial differential transport equations, and their solution yields local concentration fields which are used for the evaluation of the separation efficiency.The new modelling approach is validated by comparison with separation efficiency data obtained from experiments with CO2 desorption from saturated water-glycerine mixtures into air.

RIVER FUNCTIONING ANALYSIS FROM SUSPENDED SEDIMENT AND WATER DISCHARGE STUDY: THE CASE OF THE IVAÍ RIVER, SOUTHERN BRAZIL

This paper presents the spatial distribution of liquid and solid (suspended load) discharge in the Ivaí River Basin, and its implication in the functioning of this river system. The Ivaí is a typical medium-size river of the basaltic plateau, the left side of the Paraná River Basin in southern Brazil. The data relating to water discharge and concentration of suspended sediment come from 19 gauging stations controlled by the former Superintendence of Water Resources and Environmental Sanitation Development – SUDERHSA, today Water Institute of Paraná. The river drains an area of 36,587 km2, and its average discharge during the study period (1974–2008) was 702.9 m3 s-1. The specific discharge (Qsp = Qm:Ab) varied uniformly between 0.01 and 0.02 m3 s-1 km2, however, an anomalous result of 0.11 m3 s-1 km2 was identified. Most of the water that enters the Ivaí River comes from the smaller sub-basins (< 500 km2), and the specific discharge from the tributaries decreases from upstream to downstream, from 0.028 to 0.015 m3 s-1 km-2. Correlations are high between the annual production of suspended sediment versus average discharge (R2 = 0.97) for all river gauging stations, and the contribution of suspended load versus basin area (R2 = 0.95). The water and suspended sediment discharge of the Ivaí River is similar to those dry-wet, temperate climate river in the world. A good correlation was also obtained when the river was compared with others plateau river in the world. The results make a great contribution to the management and planning projects for many basaltic-plateau rivers along the eastern side of the upper Paraná Basin, Brazil.

Effect of bed characteristics on local liquid spreading in a trickle bed

Trickle bed reactors are important to several chemical process applications. While the available computational fluid dynamics models can predict overall liquid volume fraction, the prediction of spatial liquid distribution continues to be a challenging task. In the present work, Eulerian multifluid simulations were performed to investigate the effects of particle size, gas and liquid flow rates, and bed structure on local liquid spreading, and the predictions were validated using measured liquid spreading. It was found that the capillary pressure force caused liquid to spread in the lateral direction and that the interphase interaction forces pushed it in the downward direction and the relative magnitudes of these forces governed the local liquid distribution. While the use of existing capillary pressure force model led to satisfactory prediction of the observed trends of dynamic and steady state local liquid spreading, the modified capillary pressure force led to quantitatively correct predictions of local liquid spreading. © 2016 American Institute of Chemical Engineers AIChE J, 63: 347–357, 2017

Evaluation of the cloud thermodynamic phase in a climate model using CALIPSO‐GOCCP

AbstractLevel 1 measurements, including cross‐polarized backscatter, from the Cloud‐Aerosol Lidar with Orthogonal Polarization lidar, have been used to document the vertical structure of the cloud thermodynamic phase at global scale. We built a cloud phase identification (liquid, ice, or undefined) in the Global Climate Model (GCM)–oriented Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) Cloud Product (GOCCP) and analyzed the spatial distribution of liquid and ice clouds in five January, February, March (JFM) seasons of global‐scale observations (2007–2011). We developed a cloud phase diagnosis in the Cloud Feedback Model Intercomparison Program Observation Simulator Package to evaluate the cloud phase description in the LMDZ5B climate model. The diagnosis in the simulator is fully consistent with the CALIPSO‐GOCCP observations to ensure that differences between the observations and the “model + simulator” ensemble outputs can be attributed to model biases. We compared the liquid and ice cloud vertical distributions simulated by the model with and without the simulator to quantify the impact of the simulator. The model does not produce liquid clouds above 3 km and produces ice instead of liquid at low and middle altitudes in polar regions, as well as along the Intertropical Convergence Zone. The model is unable to replicate the observed coexistence of liquid and ice cloud between 0°C and −40°C. Liquid clouds dominate T > −21°C in the observations, T > −12°C in the model + simulator, and T > −7.5°C in the model parameterization. Even if the simulator shifts the model cloud phase parameterization to colder temperature because of the lidar instrument peculiarities, the cloud phase transition remains too warm compared to the observations.

Investigation of dynamic liquid distribution and hold-up in structured packings using ultrafast electron beam X-ray tomography

Dynamic cross-sectional liquid distribution and hold-up in a DN80 separation column filled with structured packings was studied using an ultrafast electron-beam X-ray tomograph with high temporal resolution of 2000 images per second. The modality allows visualisation and characterisation of the counter-current flow before and at the flooding point representing the upper operation limit. Two packings of the same type (Montz B1-MN) with different specific surface area were used to investigate the influence of the packing geometry on the spatial liquid distribution. The system studied was water/air at different gas and liquid loads. The results of the tomographic imaging and corresponding post-processing routines were validated by comparison with conventional draining measurements.

PAPER INK INTERACTIONS .Impact of oil-binder interaction on pore structure in paper coatings as studied by internal reflectance. Part 2: Relation to structural expansion

Abstract In the case of ink setting on coated paper, s1gmficant decrease of accessible pore volume of the coating matrix can occur due to structural changes caused by swelling of latex hinder particles when contacted with the vehicle of oil-based ink. The impact of latex swelling, reduced network connectivity and the subsequent effects on the dynamic of spatial liquid distribution characteristics within the expanded pore network were examined by a recently established optical retlectance measurement procedure based on the refractive index differences between the coating components and the surrounding medium present in the interparticle pores. GCC model coatings with latex binders displaying differing swelling characteristics were exposed to liquid supersource imbibition without application of external pressure. Effects of both linseed oil and mineral oil on binder swe lling and consequent structural expansion were studied. lt is proposed that the linear retlectance behaviour in the saturated region is related to the mechanical restriction on expansion at the transition between the saturated and partially filling regions of the porous structure, and is consistent with an approximate catenary form in the macroscopic coating dimensional change as a function of depth. A conceptual structural change factor based on the change of retlectance in the saturated region is introduced, and is shown to correlate with the porosity loss values. The results suggest differences in the structural change factors in relation to the equilibrium oil uptake, coating porosity loss, and liquid propagation. The structural change factor also correlates the reflectance gradient within the coating thickness with regard to oil uptake with hinder content as the binder Ievel is increased.

Deconvolution with Maximum Entropy Solution to Determine Local Extinction Coefficient and Local Volume Concentration Values from Laser Diffraction Data

AbstractThe traditional use of the laser diffraction technique provides line‐of‐sight liquid spray drop‐size distribution. However, deconvolution of the measurements can be performed for axisymmetric spray in order to determine local spray characteristics. In a previous publication, a new deconvolution technique making use of the maximum entropy principle was established and applied to determine the local drop‐size distributions. The entire approach was experimentally validated. In this work, the technique is employed to determine local extinction coefficient values. As in the previous investigation, the measurement procedure consists of scanning a laser beam through the spray cross‐section from the center to the edge of the spray. By use of the transmittance theory, the local extinction coefficients allow the local volume concentrations to be calculated. This theory introduces the mean scattering coefficient. The results show that this coefficient must be determined as a function of the Sauter mean diameter in order to avoid overestimation of the volume concentration. Although no proper validation is presented, the coherence of the overall approach is discussed in detail and solutions for improving the spatial resolution are presented. Finally, the local volume concentrations are combined with the local drop‐size distribution to provide local volume‐weighted, drop‐size distributions. These distributions provide information on the localization of the drops according to their diameter as well as on the spatial liquid distribution. This work illustrates applications and performances of laser diffraction technique that are rarely used.

LIEE와 Mie 산란 방법을 이용한 직분식 가솔린 엔진의 스월 및 슬릿 인젝터의 분무 특성

The spray characteristics of DISI injector have a great role in gasoline engine efficiency and emission. Thus, many researchers have studied to investigate the spray characteristics of swirl and slit injectors that are used in a DISI engine. In this study, we tried to provide spray parameters, which affect on the spray characteristics such as injection pressure, ambient pressure and ambient temperature. In addition, we calculated to investigate the break up mechanism of test injectors and obtained to evaluate the spray characteristics. As the ambient pressure increases in case of slit injector, decreases. The laser-induced exciplex fluorescence (LIEF) technique, which is based on spectrally resolved two-color fluorescent emissions, has applied to measure the liquid and vapor phases for on evaporating spray simultaneously. The TMPD/naphthalene proposed by Melton is used as a dophant to detect exciplex signal. The temporal and spatial distribution of liquid and vapor phases during the mixture formation process was measured by this technique. In the LIEF technique, the vapor phase is detected by the monomer fluorescence while the liquid phase is tracked by the exciplex fluorescence. From this experiment, we found that the spray area of the vapor phase is increased with elapsed time after injection and the area of liquid is decreased when the ambient pressure is 0.1MPa. However, the area tends to increase until the end of injection when the ambient pressure is 1.0MPa.

Two-dimensional imaging of fuel-vapour concentration byuse of LIEF technique during mixture formation process in a DIdiesel engine

The laser-induced exciplex fluorescence (LIEF)technique, which is based on spectrally resolved two-colour fluorescentemissions, has been applied to anevaporating diesel spray for the simultaneous separation ofliquid and vapour phases on the two-dimensional images. Theexciplex system is based on the TMPD/naphthalene systemproposed by Melton. The temporal and spatial distribution ofliquid and vapour phases during the mixture formation process was detected by this technique. In the LIEF technique, the vapourphase is detected by the monomer fluorescence while the liquidphase is tracked by the exciplex fluorescence. It is able toprovide quantitative information on the diffusion state forapplying the statistical entropy concept. This concept was putinto practice in the image sets obtained through LIEFmeasurement in order to investigate the diffusion process of vapour phase in the evaporating diesel spray. The lasershadowgraph was taken to deduce the effect of turbulent mixingon the ignition. The experiments were conducted in a directinjection diesel engine with optical access required forthe two-dimensional laser imaging.From the results, it is found that ignition occurs in the regionwhere turbulent mixing has advanced a nearly homogeneousmixture of fuel vapour and air. Multi-sectional images obtainedby LIEF indicate that there is a spatial dependence ofignition on the vapour-phase fuel in the combustion chamber.

Optical Diagnostics of Temporal and Spatial Evolution of a Reacting Diesel Fuel Jet

Laser Doppler anemometry, spectral extinction-absorption, and flame chemiluminescence measurements were carried out to characterize the fluid flow and to analyze the temporal and spatial distribution of liquid, vapor and some pollutant species in an optically accessed high swirl combustion chamber Extinction-absorption measurements from UV to visible have shown that the spray, strongly distorted, is mixed downstream by the high swirling flow and the vapor region expands rapidly from the tip of the jet toward the chamber walls. The entrainment of hot air into the jet accelerates the vaporization process and the strong swirling flow transports the vapor around the chamber The OH emission, indicating the spatial location of autoignition, occurs at the same crank angle as that of the minimum of the heat release rate, and in the vapor region far from the tip of the liquid jet. The first appearance of soot occurs later across a wide portion of the leading part of the jet located between the tip of the jet and the OH emission zone.

A continuum model for the transport of heat, mass and momentum in a deformable, multicomponent mush, undergoing solid-liquid phase change

Motivated by a geological problem, the continuum conservation equations governing the transport of heat, mass and momentum in a deformable multicomponent mush undergoing solid-liquid phase change are presented, and a one-dimensional (I-D) model of a layer heated from below investigated numerically. The results indicate that phase transport exercises a strong control on heat transport. The form of the spatial distribution of liquid depends upon the relative transport rates of heat and buoyant liquid; a high porosity wave may develop at the top of the mixed phase region, the amplitude of which increases with time until the contiguity of the solid matrix breaks down and a slurry forms. Phase compositions are fixed by the requirement of local thermodynamic equilibrium, and are deduced from published equilibrium phase change experiments.

Characteristics of Liquid Jet Atomization Across a High-Speed Airstream. 2nd Report. Calculation of Spatial Distribution of Liquid, Variation of Drop Diameter and Drop Trajectory.

To elucidate the atomization process of a liquid jet across a high-speed airstream, the spatial distribution of liquid, drop diameter and drop trajectory were calculated. In this model, a liquid column is not incorporated. Drops ejected from the injector have the same velocity Vl but different drop diameters, which are defined by the volume distribution of drop size. The ejected drop is broken up by the airstream. Calculated spatial distribution of liquid agrees well with measured spatial distribution of liquid. The trend of the calculated drop diameters agreed well with the trend of the measured Sauter mean diameter. The drop diameter decreases rapidly, near the injector especially along the outer line of the spray.

Comparative Imaging of Liquids in Rocks by NMR and Differential X Ray CT

ABSTRACTWe have applied NMR Imaging and X_Ray Computerized Tomography to the study of the structural properties of rocks. Samples from different porous rocks; sandstones, granites, limestones have been successively examined by both techniques. NMR images have been obtained on water saturated samples. The spatial distribution of liquid indicates the effective porosity. By constrast, X_Ray images display the mineral content of rocks. Standard tomographs do not have the required resolution to see pores smaller than 100 μm. We used water as a constrast agent to localize porosities by “differential” CT. Comparative results are shown.