Range Of Liquid Flow Rates Research Articles

CFD-aided contraction-expansion static mixer design for oil-in-water emulsification

Abstract Contraction-expansion (CE) static mixers can enable solid-liquid and liquid-liquid dispersion with low energy dissipation, low risk of obstruction, and without moving parts. In this work, the influence of CE elements of different geometries on the imposed turbulence of a flowing liquid has been assessed by a two-dimensional computational fluid dynamic (2D-CFD) simulation. The effect of CE on the dispersion of droplets of an immiscible liquid has also been analysed from simulations, using the volume of fluid (VOF) approach. Direct numerical simulation (DNS) performed by the open-source Gerris Flow Solver software was used to get the velocity fields and turbulence characteristics. Different ratios of CE diameters and lengths were analysed for liquid Reynolds numbers from 500 to 20,000. From simulations, the CE geometry that maximised the average root mean square velocity, as an indicator of turbulence, was determined for different liquid flow rates. It was found that the average RMS had a maximum for a wide range of liquid flow rates when the CE diameter ratio was between 0.55 and 0.59 and the length ratio was between 0.2 and 0.3. Then, a device with seven CE elements with geometrical features within this range was built and used for preparing an oil-in-water emulsion. The test system contained water and sunflower oil (5 % v/v) with the further addition of TritonX100 (0.5 % in volume of the solution) as surfactant. The stability of the emulsions was assessed by measuring the time evolution of turbidity (absorbance at 860 nm), to get the initial separation velocities. The emulsions prepared using the CE device showed initial phase separation rates lower than the one obtained in a stirred flask, evidencing the feasibility of using CE static mixers for preparing emulsions with relatively low energy consumption. Moreover, the emulsions obtained with the CE device, although dependent on the flow rate, showed similar features when obtained with 10, 100 and 250 passes through the CE static mixer.

Phase volume fraction measurement of vertical oil–water-gas flow using integrated optical-electrical coaxial cross-modal probe sensor

Measuring phase volume fraction is an essential part of petroleum exploration and development. According to the problems that the common sensors are unable to obtain the phase volume fraction of oil–water-gas flow, an integrated optical-electrical coaxial cross-modal probe sensor (IOECCMPS) is designed, and a phase volume fraction system based on IOECCMPS is developed for different oil–water-gas flow. Specifically, the electrical and optical mathematical models of the IOECCMPS were established, and theoretical analysis of electric field distribution and ray tracing results. We also analyzed the sensitivity distribution of the electrical measurement module (EMM). Based on the above results, the effects of structural parameters on its performance are discussed, including the electrode length, electrode thickness, the angle of the monitoring tip, and insulating tube structure. In addition, we also studied the response characteristics of the IOECCMPS in oil–water-gas flow. Furthermore, the IOECCMPS circuit was designed and experimented with on the oil–water-gas flow measurement platform. Experimental results show: the developed IOECCMPS can realize multi-phase measurement under oil–water-gas flow such as liquid flow rate range (0.42–2.92 m3/h), liquid water volume fraction range (50–90%), gas flow rate range (0.21–1.67 m3/h), etc., and the measurement error is within 5%. In the research work of this paper, the developed IOECCMPS can simultaneously accomplish the accurate measurement of phase volume fraction of oil–water-gas flow, which provides a reference for the development of oil production monitoring technology.

Analytical first-principles-based model for sprays-based CO2 capture

CO2 removal from flue gases or air is directly proportional to the overall contact area between the solvent and gas flow. Spraying the solvent offers possibilities for large area/volume ratios resulting from the small size of solvent droplets. The overall mass transfer (KGAv) is a crucial indicator of the performance of the system and indicates the overall CO2 capture rate per unit volume at given working pressure. The maximum capture rate of spray systems considered in this study is 608 kmol/m3-hr. This study develops an analytical model to predict mass transfer in spray-based systems for CO2 capture by evaluating KGAv and capture efficiency. Model predictions are validated using two experimental studies for a range of liquid flow rate, inlet solvent loading, different nozzle types, and inlet CO2 partial pressure. The relative importance of the incorporation of equilibrium partial pressure of CO2 (P*) into amine with respect to CO2 partial pressure is also studied. It is found that its effect on KGAv is prominent in high liquid flow rate and low solvent loading regimes where the overall CO2 capture is high. Finally, the variation of key parameters such as KGAv, total mass transfer coefficient (KG), effective area (Av), solvent loading (α), and mole fraction of CO2 in the gas stream (XCO2) along the channel height is studied, which gives insights on optimization of the channel height for specified operating conditions.

Multiphase Measurement of Oil Production Using Fiber-Conductance Dual-Mode Sensor

To meet the actual requirements of multi-phase measurement, a fiber-conductance dual-mode sensor (FCDMS) is designed and developed. The theoretical model of the FCDMS measurement field is established, and the light transmission process’s mathematical description and simulation analysis in the sensitive conical tip is carried out. Thereafter, The FCDMS simulation model is established by the ZEMAX ray-tracing method and Finite Element Method (FEM). the effects of structural parameters on sensitivity distribution are analyzed, including the electrode length, the radius of the electrode, and the cone angle of the sensitive tip. Furthermore, we studied the response characteristics of FCDMS in oil-gas-water multi-phase flow. At the same time, the temperature influence experiments and dynamic experiments validate the designed FCDMS, indicating the FCDMS enables measuring the phase holdup of oil-gas-water multi-phase flow. The developed FCDMS could realize the phase holdup measurement with the liquid flow rate range of 10-70m³/d, the gas flow rate range of 5-40m³/d and the liquid water holdup range of 50-90%.

Experimental Investigation of Effect of Flow Conditions on Pressure Drop of Two Phase Oil (D130)-Water Flow in Horizontal and Vertical 6-inch Annulus Pipe

The flow of oil-water in pipes commonly occurs in oil and petroleum industries and is a challenging issue. Clear understanding of the frictional pressure drop (FPD) of oil-water flows in pipes is important for determining size of pumps and pipelines in transportation of oils. An experimental investigation has been conducted for measurement of pressure drop of oil Exxsol (D130)-water two-phase flow in 6 inch diameter horizontal and vertical stainless steel annulus pipe at different flow conditions. Two-phase large scale horizontal & vertical flow loop was used to acquire data for different water cuts and fluid mixture (oil-water) flow rates. Experiments were carried out for different water cuts (WC) ranging from 0-100% and for different inclination angles (0° and 90°). The oil-water flow rates were varied from 2,000 to 12,000 barrels-per-day (BPD). Exxsol mineral oil (D130) and potable water have been used as working fluids. In order to simulate field conditions, the range of liquid flow rates used matches the range of actual flow rates in oil wells. The frictional pressure drop (FPD) has been found to decrease initially (for all flow rates) from WC=0% to WC=20%. Further increase in WC, causes FPD to increase from WC=20% to WC=40%. This is due to phase inversion. For a given WC=40%, for increase in BPD from 6,000 to 8,000, increase in FPD is about 34%. The effect of angle has found to be appreciable. For a given flow rate 8,000 BPD & WC=40%, for increase in angle from 0 to 90°, percentage increase in frictional pressure drop is about 26%. The outcomes of the study will be helpful in mitigating multi-phase flow problems in oil and petroleum industries.

A study of transition from periodic dripping to jetting in the presence of an electric field

A liquid is issued from the outlet of the capillary tube vertically, and drop formation may be in the form of periodic dripping, dripping faucet and jetting, which usually depends on flow rate or Weber number. We consider the critical Weber number (WeC=ρV02D/σ) at which the transition from periodic dripping to jetting occurs in the presence of an electric field, where high-resolution images are recorded. The necking time is mainly related to nozzle diameter and surface tension, and independent of electric potential and flow rate (in a reasonable range).The first threshold limit decreases with an increase in electric potential, where the dripping faucet is clearly affected and the point of drop detachment gradually increases. When the drop formation is in the form of dripping faucet, the transition from dripping faucet to jetting regime is enhanced by electric potential, where a sudden transition could be observed in an extremely limited range of liquid flow rate. The critical criterion (Weber number) is presented to determine the transition from dripping to jetting in the presence of an electric field. The critical Weber number is in a reasonable agreement with the experiment, although the predicted results are quantitatively divergent with experimental data.

Time averaged tomographic measurements before and after dryout in a simplified BWR subchannel geometry

For the validation of advanced two-fluid CFD models at boiling water reactor (BWR) conditions, it is necessary to have good experimental data challenging for the code by reflecting relevant flow phenomena. The present experimental study aims to provide detailed film thickness distributions in a BWR-like subchannel geometry, including spacer grids and heat transfer. This is achieved using chloroform as a working fluid, indirectly heated by hot water channels simulating BWR fuel rods. X-ray equipment was used to produce tomographic 3D-data of time-averaged attenuation coefficients which essentially represent the liquid holdup. The conversion to film thickness was done by integrating the attenuation coefficient along lines perpendicular to the rod wall and using an effective chloroform attenuation coefficient determined by numerical simulation of the experimental setup, including X-ray sensor behavior. The simulation method was validated by using two different sensors types. Measurements were performed over the whole cross-section of the channel and an axial length of 11 cm. The experiments cover a range of liquid flow rates in the pre- and post-dryout regime.

PREMATURE SHUT OFF POSSIBILITY PREDICTION FOR AUTOMOTIVE FUEL TANK SYSTEM

Prediction of the possibility of a vehicle fuel tank supply process prematureshut off is of main concern for the automotive industry. The main objectiveof this work is to show that premature shut off can be explained by the absenceof a steady state after the initial transient in the fuel supply process. Thevehicle fuel tank considered in this work is composed only of a rectilinearpipe inclined with respect to the horizontal and connected to the top of arectangular tank. The counter-current two-phase flow in the pipe is modeledusing the one-dimensional drift flux model and the tankis modeled as a control volume where mass conservation for each phase isconsidered. Linear stability analysis of the two-phase flow model shows theabsence of the steady state phase for a range of liquid flow rates before theflooding condition is achieved as a function of tube inclination and length.This fact suggests that premature shut off occurs due to the absence of asteady state regime phase during the fuel supply process.

Experimental Investigation of Two-Phase Flow Patterns in a Vertical to Horizontal Bend Pipe Using Wire-Mesh Sensor

The air-water two-phase flow plays an important role in many applications of industry fields. Usually, a 90-degree bend is used to connect pipes for changing the direction of flow which influences the two-phase flow pattern. In this paper, the effect of 90-degree bend under different ranges of gas and liquid superficial velocities on the two-phase flow patterns in the horizontal pipe located after the bend was experimentally investigated, and then results were presented and compared in a two-phase flow pattern map. Also, tomographic images and probability density functions were used to capture the cross-section void fraction and its distribution for the two-phase flow patterns. The results revealed that at low liquid and gas flow rates, a stratified-wavy flow pattern was observed as a dominant flow pattern. While the wavy-annular and semiannular flow patterns were observed at a high range of gas flow rates in the horizontal pipe. The results also showed that at the high range of liquid flow rate, bubbly, plug, slug, stratified-wavy, and wavy-annular flow patterns were observed in the horizontal pipe when the gas flow increased. The tomographic images and probability density functions gave good agreement with the experimental observations and results.

Intensification of the ozone-water mass transfer in an oscillatory flow reactor with innovative design of periodic constrictions: Optimization and application in ozonation water treatment

Ozone-water mass transfer was investigated in continuous mode using a macroscale oscillatory flow reactor provided with smooth periodic constrictions (OFR-SPC). The effects of oscillation amplitude (x0) and frequency (f) on the mass transfer coefficient (kLa) were assessed through a Doehlert experimental design. Different gas and liquid flow rates were also studied. The results show that kLa increases with f (up to 4 Hz), x0 (up to 15 mm), and the gas flow rate (up to 150 Ncm3 min−1). No significant changes in kLa were observed over a wide range of liquid flow rates (up to 180 mL min−1) and for Re0 < 1000. In all conditions studied, and among different reactor configurations tested, the higher kLa values were observed with the OFR-SPC, achieving kLa values up to 35 times higher than those obtained in a conventional bubble column. Moreover, the enhancement on the mass transfer efficiency (MTE) promoted by the oscillatory movement was more pronounced as the gas (ozone) flow rate decreases and liquid (water) flow rate increases, which is another advantage of this system when looking for large-scale implementation of the ozonation process in water treatment. Ozonation experiments using a mixture of fluoroquinolones in different matrices (distilled water, surface water and urban wastewater) were also performed, the results demonstrating that OFR-SPC is an interesting reactor alternative for ozone-driven water treatment.

CO2 REMOVAL EFFICIENCY FROM NATURAL GAS AT ELEVATED PRESSURE OF PACKED ABSORPTION COLUMN USING POTASSIUM CARBONATE PROMOTED WITH GLYCINE

This article reports the absorption removal efficiency for carbon dioxide (CO2) capture from natural gas using an environmental friendly solvent, potassium carbonate promoted with glycine. Recently, CO2 capture using this solvent (with precipitating) was studied by previous researchers. However, the precipitates of the solvent increase the potential of blockage in the packing and piping thus result failure in absorption processes. Therefore, this study focused to assess the CO2 removal efficiency of non-precipitating potassium carbonate promoted with glycine. This green solvent contains aqueous blend of 20 wt% potassium carbonate and 8 wt% glycine. The absorption performance of the solvent was obtained by demonstrated a few experimental works using a bench scale packed absorption column. The packing type was Sulzer metal gauze and the column consisted of six sampling point which located equidistance along the packing The system was running over a range of liquid flow rate 1.81-7.22 m3/m2.h at fixed operating pressure (4 Mpa), CO2 inlet concentration (20%), gas flow rate (33 kmol/m2.h) and solvent temperature (60 . The effect of liquid flow rate was assessed in term of its CO2 removal efficiency and concentration profile along the packing. The study shows the increasing trend of CO2 removal as liquid flow rate increases. Higher liquid/molar flow rate gas (L/G) offers a better absorption performance compared to lower L/G ratio. This study demonstrated the efficient absorption up to 77 % using non-precipitating potassium carbonate promoted with glycine.

Feasibility analysis of SO2 absorption using a hydrophilic ceramic membrane contactor

Abstract Hydrophilic ceramic membranes would be potential candidates for membrane gas absorption if they could be applied to appropriate separation processes. This study highlights a novel concept for the practical implementation of SO2 absorption in hydrophilic ceramic membrane that exhibits outstanding thermal and mechanical stabilities. With this aim, we investigated experimentally the performance of SO2 absorption into aqueous sodium hydroxide (NaOH) solution in a hydrophilic alumina (Al2O3) membrane contactor in terms of SO2 removal efficiency and SO2 mass transfer flux, and compared the performance with that in a hydrophobic one. A series of experiments were performed at various conditions over a NaOH concentration range of 0–1.0 mol·L− 1, a liquid flow rate range of 30–180 ml·min− 1, a gas flow rate range of 120–1000 ml·min− 1, an inlet SO2 concentration range of 400–2000 μl·L− 1, and a temperature range of 10 –35 °C. It was found that the hydrophilic membrane was more competitive when using a NaOH concentration higher than 0.2 mol·L− 1. Furthermore, it can be inferred that the hydrophilic α-Al2O3 membrane exhibited exceptional long-term stability under 480 h continuous operation.

Two-phase spray cooling with HFC-134a and HFO-1234yf on practical enhanced surfaces

An experimental study was conducted to characterize the spray cooling performance of HFC-134a and HFO-1234yf refrigerants using enhanced surfaces produced by simple processes with implications for active two-phase cooling of automotive power electronics. Experimental setup involved a closed loop spray cooling system featuring a pressure atomized spray nozzle and a 1-cm2 heater sample that simulated a high heat flux device. Heat transfer surfaces consisted of three modified surfaces, namely, electroplated-microporous, sanded, and blasted surfaces, along with a smooth surface that served as a reference. Tests were performed with saturated working fluids at room temperature (22 °C) using a range of liquid flow rates (2.5–4.5 ml/cm2 s). Based on the results, HFC-134a provided a better performance through higher heat transfer coefficient (HTC) and critical heat flux (CHF) values compared to HFO-1234yf that can mainly be attributed to the thermophysical properties and their effect on two-phase heat transfer process. The electroplated-microporous surface achieved the highest heat transfer enhancement among the tested surfaces. Overall, this study provided a framework for two-phase spray cooling performance of the current and next-generation refrigerants aimed for advanced thermal management of automotive power inverter modules towards achieving cost, size and weight reduction.

Mass transfer performance and correlations for CO2 absorption into aqueous blended of DEEA/MEA in a random packed column

The mass transfer performance of CO2 absorption into blended N,N‐diethylethanolamine (DEEA)/ethanolamine (MEA) solutions was investigated using a lab‐scale absorber (H = 1.28 m, D = 28 mm) packed with Dixon ring random packing. The mass transfer coefficient KGav, the unit volume absorption rate Φ, outlet concentration of CO2 (yCO2), and the bottom temperature Tbot of CO2 in aqueous DEEA/MEA solutions were determined over the feed temperature range of 298.15–323.15 K, lean CO2 loading of 0.15–0.31 mol/mol, over a wide range of liquid flow rate of 3.90–9.75 m3/m2‐h, by using inert gas flow rate of 26.11–39.17 kmol/m2‐h and 6–18 kPa CO2 partial pressure. The results show that liquid feed temperature, lean CO2 loading, liquid flow rate, and CO2 partial pressure had significant effect on those parameters. However, the inert gas flow rate had little effect. To allow the mass transfer data to be really utilized, KGav and yout correlations for the prediction of mass transfer performance were proposed and discussed. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3048–3057, 2017

Effect of inclination and water cut on venturi pressure drop measurements for oil-water flow experiments

This study presents an experimental investigation of pressure drop measurements in a Tercom flanged machined venturi meter of 0.5 beta ratio for oil-water two-phase flow in a 0.0762m (3-in.) pipe. Two-phase large scale inclinable flow loop was used to acquire data for different water cuts and fluid mixture flow rates. Mineral oil D80 and portable water were used for the single phase and two-phase oil-water experiments. The experiments were conducted for flow rates ranging from 2000 to 12000 bpd, water cuts varying from 0% to 100% in steps of 20%, for four flow loop inclinations (0, 40, 60, and 90 degrees) from horizontal to vertical positions. The range of liquid flow rates were selected to match the actual flow rates in real oil wells to reflect field conditions. The results show that the venturi pressure drop varies parabolically with fluid flow rate for given water cut. However, the venturi pressure drop varies linearly with water cut for given fluid flow rate. The corresponding slopes increase slightly with flow rates. The flow loop inclination has no effect on the venturi pressure drop measurements at the considered flow conditions. A new modified venturi coefficient, k, which is a function of pressure losses and geometry, was defined and its value obtained from the oil-water two-phase flow experiments. The mixture venturi pressure coefficient was also defined and determined, and the average value found to be around 15.5 for all flow loop inclinations. The results indicate that the venturi pressure drop and the determined venturi coefficients are unaffected by the flow loop inclination for selected oil-water two-phase flow conditions. In this paper, attention was focused on the variables affecting the performance of the venturi meter for oil-water flow under real oil well operating conditions.

Specific features of three-dimensional wave regimes development in a vertically falling liquid film

This Letter presents the results of an experimental study of the wave regimes of the liquid film flow over the vertical plate within a range of moderate Reynolds numbers using liquids with different physical properties. The analysis of statistical characteristics of wave fields has made it possible to elaborate the classification of three-dimensional wave regimes in a range of liquid flow rates under study. Steady-state threedimensional wave regimes are shown to occur at Reynolds numbers that are significantly higher than the Reynolds number of a transition from a two-dimensional to three-dimensional wave flow.

Experimental analyses of mass transfer and heat transfer of post-combustion CO2 absorption using hybrid solvent MEA–MeOH in an absorber

• Mass transfer of MEA–MeOH was comprehensively investigated. • The K G a v of MEA–MeOH is higher than that of MEA–H 2 O. • MeOH is vulnerable to evaporate and should be operated at a low temperature. • Optimizing operating conditions can reduce solvent evaporation. The performance of CO 2 absorption into a hybrid solvent such as monoethanolamine (MEA) in methanol (MeOH) was experimentally investigated in a lab-scale absorber packed with Sulzer DX-type structured packing, and compared with that of aqueous MEA solution. The experiments were performed at various key operating conditions over a MEA concentration range of 2.5–5.0 kmol/m 3 , a CO 2 lean loading range of 0–0.373 mol/mol, a liquid flow rate range of 2.92–16.09 m 3 /m 2 h, an inert gas flow rate range of 24.37–63.54 kmol/m 2 h, a CO 2 partial pressure range of 6.7–13.8 kPa, and an inlet liquid temperature of 10 °C. The absorption performance was presented in terms of the overall gas phase mass transfer coefficient ( K G a v ), CO 2 concentration and system temperature profiles along the height of the absorber, and the system temperatures at the bottom and the top of the absorber, T bot and T top , respectively. It was found that the K G a v for MEA–MeOH was higher than that of MEA–H 2 O. In addition, the experimental results showed that key operating parameters such as MEA concentration, CO 2 loading, liquid flow rate and inert gas flow rate have large effect on the performance of CO 2 absorption into the MEA–MeOH.

Experimental study on flooding and flow reversal in small diameter tubes with various inclinations and horizontal lengths

Lubricant oil return to compressor in household refrigerator is controlled by oil-refrigerant two-phase flow behavior in the suction pipe. Conditions of flooding and flow reversal were considered as a conservative bound for the oil return. Phenomena associated with counter current flow limitation (CCFL or flooding) and flow reversal were experimentally investigated using small diameter tubes with vertical, inclined and crank-type configurations. Flooding and flow reversal phenomena were visually observed. Both flooding and flow reversal points were measured using various shapes of test section in a wide range of liquid flow rate. The gas velocities for flooding were found to be inversely proportional to the liquid flow rates and independent of the tube configurations. The gas velocities for the flow reversal point appeared to be at a similar level over a certain range of liquid flow rate but strongly depend on the inclination angle, horizontal length and kind of liquid.

Influence of chemical species on the determination of arsenic using inductively coupled plasma mass spectrometry at a low liquid flow rate

The effect of common arsenic species on the ICP-MS signal working at a low liquid flow rate was investigated, taking into account the influence of the analytical concentration and of the matrix, comparing various sample introduction systems. Significant decrease (up to 65%) in the relative sensitivity of arsenite compared to arsenate was found, while methylarsonate, dimethylarsinate and arsenobetaine gave the same response (within 6%) as arsenate, throughout the 20–1000 μL min−1 liquid flow rate range. The effect was independent of the analytical concentration in the 1–100 μg L−1 range, and it was ascribed to processes related to both the sample introduction system and the ion generation and transport. Ion defocussing due to dissimilar kinetic energy of the arsenic ions generated from arsenite and arsenate was ruled out. Results obtained by various micronebulizer/spray chamber configurations showed that the temperature of the spray chamber is relevant in determining the relative responses of the arsenic species: heating the spray chamber at 60 °C caused a decrease in relative sensitivity of arsenite and dimethylarsinate compared to arsenate, while the arsenite-to-arsenate signal ratio was improved by cooling at 4 °C. The relative response of arsenite and arsenate was also significantly influenced by the presence of ammonium phosphate, which mitigated the difference between the species using conventional sample introduction devices. The influence of the chemical species on the ICP-MS signal was also investigated for species of other elements, finding significant differences in sensitivity for Hg, Se and Sn compounds when working at a low liquid flow rate. The results proved to have an effect on the accurate quantification of total concentration, as well as for arsenic speciation analysis by μHPLC/ICP-MS.

Research of Wet Gas Experimental Facility with Adjustable and Intermediate Pressure

In order to better simulate the flowing condition of wet gas, Tianjin University has designed and built up a wet gas flow experimental facility with adjustable and intermediate pressure in the flow laboratory. The designed pressure of the facility which used standard meter method and dual closed-loop design is 4MPa. The experiment medium is air and water, and the highest operation pressure is 1.6MPa. The gas flow rate range is 3~1000m3/h, and the liquid flow rate range is 0.05~8 m3/h. This article includes the structure introduction of the facility and the calculation of pressure loss of the system, etc. By the uncertainty assessment for the discussed facility, the conclusion is stated that the facility’s gas measurement uncertainty is 1% and the facility’s liquid measurement uncertainty is 0.35%.