Fluid flow and gas absorption in an ejector venturi scrubber

Empirical models were developed to describe the fluid flow characteristics and gas absorption efficiency of an ejector venturi scrubber. The empirical constants were determined experimentally using stop action photographs of the spray, static pressure measurements, and sulfur dioxide absorption efficiencies. To take photographs of the spray, a 2 foot high, clear plastic ejector venturi scrubber was used, with a 4 inch diameter gas entrance port. Photographic equipment included a Hasselblad camera, Xenon flash lamp, and Polaroid 667 ASA 3000 film. Exposure duration was about 1 microsecond, resulting in complete stop-action of the spray droplets at liquid rates up to 6 gpm. Droplet size ranged from 34 to 563 microns, with a volume mean diameter of 155 microns, at a liquid rate of 6 gpm. The sulfur dioxide mass transfer coefficient (Kga) varied from 0.6 to 796 lb-moles/hr-ft3 as the liquid delivery rate was varied from 1 to 8 gpm (i.e. from no atomization to complete atomization)

Devices and methods for wet gas flow metering: a comprehensive review

Wet gas is commonly encountered in various industries, including energy, chemical, and electric power sectors. For example, natural gas extracted from production often contains small amounts of liquid, such as water and hydrocarbon condensates, which classifies it as wet gas. The presence of liquid within the gas poses challenges for accurate flow measurement. To improve the performances of wet gas flow metering methods, significant research and development efforts have been invested into the wet gas flow metering technologies due to their vital importance in the production, transfer, and trade benefits. This paper presents a comprehensive overview of the recent development of wet gas flow metering. Firstly, a comprehensive discussion of the Lockhart-Martinelli parameter (Xlm) and its relation to the gas void fraction (Óg) is presented, which was mostly overlooked in previous wet gas research work. The occurrence of various flow patterns in wet gas conditions at different orientations (horizontal and vertical) was explored. Following an investigation of pressure impact on the wet gas flow patterns and development of the wet gas regions, a different test matrix for further research work was suggested. After a novel classification of wet gas measurement methods, the paper offers a detailed comparison of differential pressure (DP) meters including Venturi, Cone meter, and orifice meters, by considering both liquid and gas flow rate measurements. Secondly, the paper discusses and compares vortex flow meters, Coriolis and ultrasonic meters in comparison to DP meters. Notable phase fraction meters are also examined and compared to one another. Thirdly, the paper reviewed the concept of existing and potential hybrid wet gas meters, conducting a detailed discussion and comparison with commercial solutions by evaluating their ranges and accuracies. This assessment provides valuable insights into the capabilities of these hybrid meters, highlighting their potential to enhance the measurement of wet gas flow rates

Modelling of flows in vertical pipes and its application to multiphase flow metering at high gas content and to the prediction of well performance

Imperial Users onl

Estimation of volumetric flow rate in a square duct: Equal area versus log-Tchebycheff methods.

Accurate measurement of the volumetric airflow rates in a duct is critical to room comfort and energy saving in HVAC industry. Presently, the Equal Area and the Log-Tchebycheff methods are extensively used in practice. Both methods deduce the flow rate based on averaging discrete point velocities along the cross section while their difference is associated with the rules in specifying the measurement locations. This study aims at evaluating the Equal Area and the Log-Tchebycheff methods in deducing airflow rate in a 0.46 m square duct up to 40 Dh long, over a range of Reynolds number from 10,000 to 500,000. The numerical investigation evaluated the two methods for ideal flow conditions in the absence of practical imperfections. The airflow was simulated in a three-dimensional space using the commercial CFD code FLUENT with the RNG k-epsilon turbulence model. Based on the simulated flow field, the volumetric flow rates were calculated according to the Equal Area and the Log-Tchebycheff methods. It was observed that the Equal Area method overestimated the flow rate by 3.5 ∼ 4.7% while the Log-Tchebycheff method\u27s values fell within -0.4 ∼ 0.8% of the actual flow rates. (Abstract shortened by UMI.)Dept. of Mechanical, Automotive, and Materials Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2005 .Z46. Source: Masters Abstracts International, Volume: 44-03, page: 1500. Thesis (M.A.Sc.)--University of Windsor (Canada), 2005

Frequency Response Characteristics Of Respiratory Flow-meters

abstract: Flow measurement has always been one of the most critical processes in many industrial and clinical applications. The dynamic behavior of flow helps to define the state of a process. An industrial example would be that in an aircraft, where the rate of airflow passing the aircraft is used to determine the speed of the plane. A clinical example would be that the flow of a patient's breath which could help determine the state of the patient's lungs. This project is focused on the flow-meter that are used for airflow measurement in human lungs. In order to do these measurements, resistive-type flow-meters are commonly used in respiratory measurement systems. This method consists of passing the respiratory flow through a fluid resistive component, while measuring the resulting pressure drop, which is linearly related to volumetric flow rate. These types of flow-meters typically have a low frequency response but are adequate for most applications, including spirometry and respiration monitoring. In the case of lung parameter estimation methods, such as the Quick Obstruction Method, it becomes important to have a higher frequency response in the flow-meter so that the high frequency components in the flow are measurable. The following three types of flow-meters were: a. Capillary type b. Screen Pneumotach type c. Square Edge orifice type To measure the frequency response, a sinusoidal flow is generated with a small speaker and passed through the flow-meter that is connected to a large, rigid container. True flow is proportional to the derivative of the pressure inside the container. True flow is then compared with the measured flow, which is proportional to the pressure drop across the flow-meter. In order to do the characterization, two LabVIEW data acquisition programs have been developed, one for transducer calibration, and another one that records flow and pressure data for frequency response testing of the flow-meter. In addition, a model that explains the behavior exhibited by the flow-meter has been proposed and simulated. This model contains a fluid resistor and inductor in series. The final step in this project was to approximate the frequency response data to the developed model expressed as a transfer function.Dissertation/ThesisM.S.Tech Electrical Engineering 201

Multiphase flow rate measurement using a novel conductance Venturi meter : experimental and theoretical study in different flow regimes

Multiphase flows, where two or even three fluids flow simultaneously in a pipe are becoming increasingly important in industry. Although much research has been done to measure the phase flow rates of two-phase flows using a Venturi meter, accurate flow rate measurements of two phase flows in vertical and horizontal pipes at different flow regimes using a Venturi meter remain elusive. In water continuous multiphase flow, the electrical conductance technique has proven attractive for many industrial applications. In gas-water two phase flows, the electrical conductance technique can be used to measure the gas volume fraction. The electrical conductance is typically measured by passing a known electrical current through the flow and then measure the voltage drop between two electrodes in the pipe. Once the current and the voltage drop are obtained, the conductance (or resistance) of the mixture, which depends on the gas volume fraction in the water, can then be calculated. The principal aim of the research described in this thesis was to develop a novel conductance multiphase flow meter which is capable of measuring the gas and the water flow rates in vertical annular flows and horizontal stratified gas water two phase flows. This thesis investigates the homogenous and separated (vertical annular and horizontal stratified) gas-water two phase flows through Venturi meters. In bubbly(approximately homogenous) two phase flow, the universal Venturi meter (nonconductance Venturi) was used in conjunction with the Flow Density Meter, FDM (which is capable of measuring the gas volume fraction at the inlet of the Venturi) to measure the mixture flow rate using the homogenous flow model. Since the separated flow in a Venturi meter is highly complex and the application of the homogenous flow model could not be expected to lead to highly accurate results, a novel conductance multiphase flow meter, which consists of the Conductance Inlet Void Fraction Meter, CIVFM (that is capable of measuring the gas volume fraction at the inlet of the Venturi) and the Conductance Multiphase Venturi Meter, CMVM (that is capable of measuring the gas volume fraction at the throat of the Venturi) was designed and manufactured allowing the new separated flow model to be used to determine the gas and the water flow rates. A new model for separated flows has been investigated. This model was used to calculate the phase flow rates of water and gas flows in a horizontal stratified flow. This model was also modified to be used in a vertical annular flow. The new separated flow model is based on the measurement of the gas volume fraction at the inlet and the throat of the Venturi meter rather than relying on prior knowledge of the mass flow quality x. Online measurement of x is difficult and not practical in nearly all multiphase flow applications. The advantage of the new model described in this thesis over the previous models available in the literature is that the new model does not require prior knowledge of the mass flow quality which makes the measurement technique described in this thesis more practical.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Special Instrumentation for Two-Phase Flow

The design of engineering systems, involving two-phase flow, such as nuclear water reactors, requires the ability to model and predict the detailed behavior of those flows and the phenomena that they manifest, with a required degree of accuracy. In the past a significant amount of effort has been addressed to the development of intrusive and nonintrusive measurement techniques of two-phase flows, with special application to the determination of mass flow rates. Many extensive experiments are being performed to investigate in detail loss of coolant accidents (LOCA). During these experiments the coolant is released as a two-phase mixture through a simulated break of a coolant pipe, and the measurement of the mass flow rate of the two phases was required to analyze the accident evolution and consequences. In this context, most flow meters have been designed to measure the single-phase flow of a Newtonian fluid, and then used to measure quantities in more complex fluids. The key to fundamental understanding of two-phase flow is still the careful development of specialized instrumentation, in particular for special and complex geometrical applications. Within the framework of an Italian R&D program on Nuclear Fission, supported by the Ministry of Economic Development, the SPES3 experimental facility, able to simulate the innovative small and medium size PWR nuclear reactors, is being built and will be operated at SIET Company laboratories. In such facility some design and beyond design basis accidents, like LOCAs, with and without the emergency heat removal systems, will be simulated. In most accident simulations, a two-phase flow mixture will occur in the lines, during the transient evolution, due to the simulated strong depressurization of the system. An accurate accident analysis requires the measurement of the mixture mass flow rate and for this reason, instruments and methodologies to evaluate different two-phase flow parameters need to be developed. Typically a set of instruments (Spool Piece - SP) must be installed in order to evaluate the mass flow rate of the phases in a large range of flow patterns, pressures and temperatures. An ideal SP is a control volume constituted by different measurement instruments, fed with a two-phase flow. In single-phase flow, each instrument is able to measure a well defined flow parameter, while the instrument signal interpretation, in two-phase flow, is not easy due to the different flow patterns and the to the large number of parameters that influence the flow, so that a model of the SP, depending on the geometry and on the SP orientation, is required. Moreover the selection of the instruments strongly depends on the experimental conditions: pressure, temperature and phases velocities. The thesis work consists in the development of special instrumentation and in the development of models, based on the analysis of experimental data, that are able to interpret the measurement signals for many possible two-phase conditions. The two different measurement fields, internal flow structure investigation and instrument modeling for phases mass flow rate reconstruction purposes, have been analyzed. In the first field the instrumentation must be able to characterize momentum, mass, energy balance with a resolution sufficient to investigate local phenomena and characteristic structure (interface evolution, void profiles, liquid film level, characteristic frequencies, etc..). The investigation of an horizontal two-phase flow has been performed by means of a Wire Mesh Sensor. Local, chordal, cross-section void fraction values are derived from the sensor data in a wide range of phases superficial velocities, and a new signal methodology, able to characterize the flow in terms of phases distribution (flow patterns) and time evolution, has been developed. Moreover the methodology allows the extraction of important flow information, such as the local and time average void fraction, the interface evolution, and characteristic frequencies. The evolution of the void fraction profiles has been related to the superficial velocity of the two-phases (Jg and Jl) and the flow evolution in time and space has been analyzed and discussed, showing that such methodology is useful to identify and characterize in detail the two-phase flow. Concerning the second measurement field, the analysis of the instruments used for two-phase flow measurement applications has been described. This bibliographic research allowed the definition of the candidate instruments suitable to be installed in a nuclear safety experimental facility, and their measurement characteristics. The selection of the candidate instruments has been made defining some fundamental criteria that should be satisfied: range of measurement, dynamic response, installation requirements, materials/electrical compatibility with pressure and temperature conditions, flow velocity compatibility. The selected instruments have been experimentally studied in different pipe configurations, and different models have been developed for each one. Different instrument combinations have been tested, and the performance of each one has been analyzed in terms of estimation of the mass flow rate of the two phases. The performed research allows the identification of the advantage and drawbacks of the different instrument combinations, and the identification of the phases mass flow rate measurement accuracy achievable for each SP configuratio

USCID water management conference

Presented at Emerging challenges and opportunities for irrigation managers: energy, efficiency and infrastructure: a USCID water management conference held on April 26-29, 2011 in Albuquerque, New Mexico.Includes bibliographical references.Verifying conservation estimates for on-farm agricultural water conservation programs -- Improving irrigation system performance in the Middle Rio Grande through scheduled water delivery -- Urbanization of irrigation districts in the Texas Rio Grande River Basin -- Urbanization issues in the Middle Rio Grande Conservancy District -- From canyons to canals: applying regulated river research to canal bank analysis -- Water for irrigation, streams and economy: evaluating past and future climate change to secure a reliable water supply for multiple needs -- Flow measurement capabilities of diversion works in the Rio Grande Project area -- Open-channel and pipe flow measurement at Mohave Valley Irrigation and Drainage District using Venturi technology with bubbler sensors -- Using an ADCP to determine canal seepage losses in the Middle Rio Grande Conservancy District -- Venturi meters constructed with pipe fittings: an under-appreciated option for measuring agricultural water -- Improving crop water use determination using adjusted eddy covariance heat fluxes -- Performance evaluation of TDT soil water content and Watermark soil water potential sensors -- Meeting water challenges in Idaho through water banking -- Water transfers in California: 20 years of progress, view to the future