Characterisation of Vertical Upward Gas-Liquid Flow Using a Non-Intrusive Optical Infrared Sensor

The pursuit to improve accuracy, cost effectiveness and safety in the operation of multiphase flow metering sums up the motivation for this work. Non-intrusive optical infrared sensors (NIOIRS) of 880 nm and 1480 nm wavelengths have been applied in this work for the objective identification of flow regimes, determination of phase fractions and ultimately for the measurement of phase volumetric flowrates in an upward vertical gas liquid flow. The sensing method detects flow structures based on the disparity of optical properties of each fluid. Air and water were used as working fluids to create GLF in vertical test and main rig setups with 0.018 m x 1 m and 0.0273 m x 5 m test section respectively under varied fluid flow rate combinations (0- 1.0 m/s of water and 0 - 13 m/s of air). Notable contributions were made in this work. These include (i) a derivation of a flow regime dependent phase fraction model, which accounts for interfacial scattering, hence improves phase fraction measurement (ii) A novel application of supervised learning methods to improve objective flow regime identification for a GLF (iii) Application of a modified calibration model to measure actual liquid velocities and flow rates In the absence of priori superficial velocities and slip ratio information (iv) a scheme to convert the NIOIRS into a GLF meter

Multiphase flow measurement in the slug regime using ultrasonic measurement techniques and slug closure model

Multiphase flow in the oil and gas industry covers a wide range of flows. Thus, over the last decade, the investigation, development and use of multiphase flow metering system have been a major focus for the industry worldwide. However, these meters do not perform well in slug flow conditions. The present work involves experimental investigations of multiphase flow measurement under slug flow conditions. A two-phase gas/liquid facility was designed and constructed at Cranfield University. It consisted of a 0.05 m diameter 25 m long horizontal pipeline with the necessary instrumentation. An ultrasonic multiphase metering concept has been proposed and investigated. The concept was based on the combination of non-invasive and non-intrusive ultrasonic sensors and a slug closure model. The slug closure model was based on the "slug unit" model to infer the gas and liquid phase volumetric flowrates. The slug characteristics obtained by non-invasive and non-intrusive ultrasonic techniques were inputs to slug closure model which calculates the factors KI (Liquid), K2 (Liquid), K3 (Gas) and K4 (Gas). These factors are function of the slip ratio in the slug body, flow profile (CO), drift velocity (Vd), liquid holdup and gas void fraction in slug body, slug length, film length, and the total length of the slug unit. Based on ultrasonic sensor measurements, the slug translational velocity was estimated and the slug closure model then calculates the gas and liquid phase volumetric flowrates. Air water slug flow data were gathered and processed for a range of superficial velocities VSL=0.3 to 1.03 ms'1 and VsG=0.6 to 3.01 ms'1. The overall goal of a 5% relative error metering for both phases was not achieved for the conditions tested. The liquid phase percentage errors were from -63.6% to 45.4% while the gas phase percentage errors were from 42% to -14.6%. Key words: slug flow, slug characteristics, slug closure model, non-invasive ultrasonic, non-intrusive ultrasonic, clamp-on transit time ultrasonic flowmeter

A study of flow behaviour of dense phase at low concentrations in pipes

Offshore production fluids from the reservoir are often transported in pipelines from the wellheads to the platform and from the platform to process facilities. At low flow velocity water, sand or liquids like condensate could settle at the bottom of pipelines that may lead to grave implications for flow assurance. During shutdown the settled heavy liquid (e.g. water), could result in corrosion in pipelines, while following restart stages the settled water could form water plugs that could damage equipment, while settled sand could also form a blockage that needs to be purged. Furthermore, there is a requirement to know the quantity of water and base sediment for fiscal metering and custody transfer purposes. A series of experiments were carried out to observe low water cut in oil and water flows in four inch diameter pipeline. Similarly low sand concentrations in water and sand, water, air and sand flows were observed in two inch diameter pipelines. Conductive film thickness sensors were used to ascertain structural velocities, height and dense phase fractions. Comparisons are made between two cases in order to gain better understanding of the behaviours and dispersal process of low loading denser phase in multiphase flows. The arrangement enabled production of flow regime maps for low water cut oil and water flow, as well as water sand and water, air and sand flows, structural velocities and denser phase removal velocities were also ascertained. Actual in-situ liquid velocities were obtained experimentally. A novel detection of sand in water and water and sand flows was produced. The experimentally obtained film thickness was in agreement with two fluid model predictions. Thus, confirming use of conductive sensors for dense phase classification, film thickness, velocity and holdup measurements in pipelines

Annual report of the National Advisory Committee for Aeronautics (41st). administrative report including Technical Report nos. 1210 to 1253

Report includes the National Advisory Committee for Aeronautics letter of submittal to the President, summaries of the committee's activities and research accomplished, bibliographies, and financial report

Process Analytics from Passive Acoustic Emissions Monitoring during Fluidized Bed Pellet Coating in Pharmaceutical Manufacturing

Piezoelectric microphones were attached to a top spray fluidized bed to provide valuable process signatures. Relationships were developed between sound waves and conditions within the fluidized bed to relay critical quality and performance information. Deep learning analytics were used to extract valuable information from experimental data. Advancements in passive acoustic emissions monitoring will play a key role in optimizing pharmaceutical manufacturing pathways to ensure drug quality and performance

In-line powder flow behaviour measured using electrostatic technology

Within solid-dose manufacturing processes, powder flow and powder triboelectrification are critical to the quality of the final product. Off-line testers do not simulate the shear and packing conditions that a powder would experience in-process and may be unreliable in predicting in-line flow and charging properties, which are key components to successful formulation and process design. In this work, a dual-electrode, electrostatic powder flow sensor (EPFS) was used to obtain electrostatic signals that were generated in response to the pattern of flow of pharmaceutical powders in two density modes: The first being powders in lean phase flow, generated by free-fall of the powder from the outlet of a screw-feeder. The second being dense phase flow, through either 19.1 mm Ii.Dd. stainless-steel pipe or at the outlet of a tablet-press hopper. Powders were selected from a range of low to high cohesivity so as to study the effect of powder cohesion on the flow pattern. Electrostatic signals were then analysed by three distinct signal processing methods (RMS signal averaging, cross correlation, and Fast-Fourier-Transform) with a view to determining certain characteristics of powder flow, i.e. mass flow rate; cohesivity; and triboelectrification. In the first application a calibration was attempted to establish the link between the root-mean-square (RMS) of the electrostatic signal and the mass flow, as determined by the accumulation of mass on a balance placed below the screw-feeder (in the case of lean phase application) and the 19.1 mm i.d. pipe (in the case of dense phase application). In both cases it proved unsuccessful, owing to the instability in the electrostatic signal (i.e. its dependence on factors other than mass flow, for example inherent and induced charge fluctuations and moisture content). An alternative method for determining mass flow rate was proposed based on the second signal processing method, which involved the cross-correlation of signal from both sensors to determine the free-fall velocity. This method might work in future applications if combined with a suitable technique for determining the powder density. In the second application, a Fast-Fourier-Transform (FFT) of the electrostatic signal to yield an FFT spectrum was used to establish whether this technique could determine aspects of powder cohesivity. A correlation in rank order of cohesivity was observed between the ratio of the summed or averaged amplitudes at the three principle frequencies to the summed or averaged of the baseline components respectively, and the cohesivity of the powders, as determined by off-line powder rheometry assessments of dynamic flow and bulk properties. In the third application, the RMS signal normalised to the powder mass flow rate was used to study the time-dependent powder charging behaviour, which is induced by the transportation of the powder within the screw feeder. Characteristic relative charging profiles were obtained for each powder, which in some cases were coupled to charge-induced adhesion of the powder to the equipment. In the last application, the RMS signal generated from the EPFS sensor located at the outlet of the hopper on a rotary tablet press was used to interrogate the dense-phase intermittent-flow resulting from the dosing of the tablet die. Those more cohesive powders gave a larger RMS signal at the lower electrode (relative to the upper electrode) whereas less cohesive powders had similar RMS signals at each electrode. While the exact explanation of this effect is currently unknown these results suggest that the technique might be useful in the determination of die filling as a function of the input material characteristics. In summary, this work has provided some insight into the potential applications of EPFS for in-line measurement of powder flow and charging characteristics. Future work should focus on (i) developing an integrated sensor with an independent measurement of density to yield the powder mass flow using an inferential approach, (ii) co-use of techniques (such as Faraday-cup and charge decay analysers) to validate the in-line charging behaviour, (iii) further exploration of the significance of the signal amplitude difference at the tablet press hopper outlet in on the characteristics of the tablet compact

Multiphase flow measurement in the slug regime using ultrasonic measurement techniques and slug closure model

Multiphase flow in the oil and gas industry covers a wide range of flows. Thus, over the last decade, the investigation, development and use of multiphase flow metering system have been a major focus for the industry worldwide. However, these meters do not perform well in slug flow conditions. The present work involves experimental investigations of multiphase flow measurement under slug flow conditions. A two-phase gas/liquid facility was designed and constructed at Cranfield University. It consisted of a 0.05 m diameter 25 m long horizontal pipeline with the necessary instrumentation. An ultrasonic multiphase metering concept has been proposed and investigated. The concept was based on the combination of non-invasive and non-intrusive ultrasonic sensors and a slug closure model. The slug closure model was based on the "slug unit" model to infer the gas and liquid phase volumetric flowrates. The slug characteristics obtained by non-invasive and non-intrusive ultrasonic techniques were inputs to slug closure model which calculates the factors KI (Liquid), K2 (Liquid), K3 (Gas) and K4 (Gas). These factors are function of the slip ratio in the slug body, flow profile (CO), drift velocity (Vd), liquid holdup and gas void fraction in slug body, slug length, film length, and the total length of the slug unit. Based on ultrasonic sensor measurements, the slug translational velocity was estimated and the slug closure model then calculates the gas and liquid phase volumetric flowrates. Air water slug flow data were gathered and processed for a range of superficial velocities VSL=0.3 to 1.03 ms'1 and VsG=0.6 to 3.01 ms'1. The overall goal of a 5% relative error metering for both phases was not achieved for the conditions tested. The liquid phase percentage errors were from -63.6% to 45.4% while the gas phase percentage errors were from 42% to -14.6%. Key words: slug flow, slug characteristics, slug closure model, non-invasive ultrasonic, non-intrusive ultrasonic, clamp-on transit time ultrasonic flowmeter.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

A study of climbing-film flow characteristics of various liquids and air in an annular duct

Momentum transfer in climbing-film flow in an annular duct was investigated. Air and various liquids, with a wide range of viscosities and surface tensions, were investigated. The two phases flowed co-currently upward, the liquid climbing as a thin film on the inner wail while the outer wall remained dry. The annulus was constructed of a three inch I. D. acrylic plastic tube and a one inch O. D. stainless steel rod. The dry, clear plastic outer wall made determination of pressure losses in the gas phase, radii of the point of maximum velocity, and outer wall shear stresses straightforward. High-speed motion picture photography of the liquid film was used to study the liquid film thickness and the wave character of the liquid surface. It was attempted to determine the effect of the liquid properties on the character of the liquid film and on the hydrodynamics of the air-liquid flow. The liquids used were water, Shellsolv, iso-octyl alcohol and light oil (viscosity ranging from 6.75x10⁻⁴ to 1.22x10⁻² lbm/ft sec and surface tension ranging from 24.4 to 72.75 dyne/cm at 68°F). The experimental investigation covered an air flow range of 7x10⁴<Re<2x10⁵ and a liquid flow range of 0.10 to 0.755 lbm/min. The results of this investigation are subsequently presented. 1. Friction factors for air flowing alone in the annulus were 2% to 13% larger than smooth tube values. The radius at the point of maximum velocity was in agreement with the values predicted by existing empirical correlations. 2. The two-phase pressure losses increased with increases in air and liquid flow rates. At the same liquid flow rate, the pressure losses were larger for the more viscous liquids. 3. The presence of the liquid film flowing on the inner wall caused only small changes in the outer wall shear stress from the single-phase values. Correlations were found for friction factor and Reynolds number using the region between the point of maximum velocity and the outer wall as the hydraulic flow region. In the region of low liquid entrainment the following empirical correlation was found f₂ = .201 Re₂⁻.³²⁶ 4. The radius of the point of maximum velocity increased as the liquid flow rate increased and was larger for the more viscous liquids. The following empirical correlation was found y* = .01 ReL.²⁴⁶μ*.⁴⁸ 5. The two-phase pressure losses were predicted well by the Lockhart and Martinelli correlation over the entire range of the data and for all liquids. 6. The laminar film model gives a reasonable approximation of the liquid film thickness for all the liquids investigated. The data indicate that the film thickness is proportional to the liquid viscosity to the .3 power. 7. Shear stresses at the air-liquid interface were 33% to 52% larger than the outer wall shear stresses and 7% to 130% larger than the inner wall shear stresses. The interfacial and the inner wall shear stresses approach each other at the high air flow rates, indicating the velocity profile in the liquid film is approaching linearity. 8. The frequency of the waves on the liquid surface increase as the air and liquid flow rates increase. The frequency was larger for the less viscous liquids and also for the liquids with the lower surface tensions. The wave celerity increases with increases in air and liquid flow rate and was 3% to 6% of the average air velocity. This compares well with the 5% to 10% reported for a liquid film climbing on a tube wall