Average Liquid Flow Research Articles

Development and field application of a jetting and helical combination tool

Liquid loading occurs in gas wells after a period of production, and the vortex drainage gas recovery technology can alleviate this problem by removing liquid. To substantially enhance the efficiency of this technology, a novel tool combining jetting and helical mechanisms has been introduced. To validate its effectiveness, a laboratory system for detailed analysis of pressure drops by using various tools at multiple gas flow rates has been set up. The analysis approach encompasses both single-factor and orthogonal analyses of tool structure parameters to find out the optimal tool structural parameters under different operating conditions. Consequently, a correlation between the gas flow rates observed in controlled laboratory environments and those in actual gas wells has been established. The study indicates that the tool’s main structural parameters significantly impact pressure drops along the wellbore. Furthermore, it is evident that distinct well profiles require unique tool setups to minimize such pressure drop. Field tests of the optimized tool have shown notable enhancements: The average gas flow rate increased by 25.9%, reaching 5.39 × 104 m3/d (1.90 × 106 scf/d), while the average liquid flow rate increased by 20.1%, reaching 1.46 m3/d (9.18 bbl/d). These results highlight the superior drainage stimulation effect of the new jetting and helical combination tool, presenting novel insights and methodologies for enhancing gas recovery in liquid-loaded gas wells.

GET 63–2019: Innovative Method for Stabilizing Liquid Flow Rate in a Reference Installation 3

Establishing the pinpoint accuracy of national primary standards for units of mass and volume flow rates (mass and volume) of liquid (water) is a priority in the national economy of most states. In Russia and abroad, the principle of operation of standards for units of flow rate and amount of liquid is based on the gravimetric weighing method, i. e., on measuring the mass of liquid entering a weighing container over a certain averaging time interval. The decisive condition for the accuracy of the result of the standard is the stabilization of liquid flow rate, as well as the choice of the optimal method for creating a forced flow of liquid in the pressure pipeline and measuring line. The widely accepted method of creating a forced flow of liquid by placing it at a height or supplying it using pumps has one inconvenient consequence – the bulkiness of the standard design. The creation of such a design entails economic, labor, and time costs, which can adversely affect the test conditions and results. The author’s innovative method of active damping of pressure and fluid flow fluctuations, which eliminates the need to place the pressure tank at a great height above ground level, allows minimizing inconveniences. This method is implemented in the pressure pipeline and measuring line of the reference installation 3 of the State Primary Special Standard of Units of Mass and Volume of Liquid in a Flow and of Mass and Volume Flow Rates of a Liquid GET 63–2019. The purpose of the article is to substantiate and experimentally confirm the high efficiency of this method. The results of experimental research of changes in the absolute pressure in the air cushion and the liquid level in the pressure tank of the stabilization module confirmed the efficiency of the proposed method based on the obtained minimum values of the relative deviations of the instantaneous and average liquid flow rates. The engineering solution presented in the article is of interest to economic entities and commercial organizations interested in reducing the costs of testing the volumetric flow rate (mass and volume) of liquid (water).

Convective effects on columnar dendritic solidification – A multiscale dendritic needle network study

Gravity-induced buoyancy, inevitable in most solidification processes, substantially alters the dynamics of crystal growth, such that incorporating fluid flow in solidification models is crucial to understand and predict key aspects of microstructure selection. Here, we present a multi-scale Dendritic Needle Network (DNN) model for directional solidification that includes buoyant flow in the liquid, and apply it to a range of alloys and growth conditions. After a brief presentation of the model, we study the selection of stable primary dendrite arm spacings in Al-4at.%Cu and in Ti-45at.%Al alloys under different gravity levels, comparing both applications to published phase-field results and experimental measurements. Then, we simulate the oscillatory growth behavior recently reported via X-ray in situ imaging of directional solidification of nickel-based superalloy CMSX-4. In this last application, the DNN simulations manage to reproduce the oscillatory growth behavior, and hence permit identifying the fundamental mechanisms behind the oscillatory growth regime. In particular, we show that sustained oscillations occur when the average liquid flow velocity is close to the crystal growth velocity, and that primary dendritic spacings also play a crucial role in the oscillatory behavior.

Two-dimensional dynamic model of the interaction of a fluid and a piezoelectric bending actuator in a plane channel

The paper proposes a two-dimensional computer model of the fluid flow in a plane channel under the action of an applied pressure drop with a flat ceramic piezoelectric actuator immersed in it, bending in the transverse direction in proportion to the applied electric voltage. A mathematical model of the coupled liquid-piezodrive system in variational form for numerical simulation by the finite element method is proposed. Since the assignment of the Dirichlet boundary conditions for displacement in this problem, is difficult, an equivalent piezo actuator deformation scheme using the Neumann boundary conditions is constructed. The deformations and equivalent stresses of von Mises on a piezo actuator are calculated. The influence of the geometry of the channel and the hydrodynamic resistance formed by the piezo actuator on the dynamics of the fluid flow is analyzed. An algorithm is proposed for adaptive dynamic remeshing of the channel computational mesh under deformations exceeding the size of finite elements. With a symmetric control signal supplied to the piezoelectric actuator, the asymmetry of the geometry leads to a violation of the symmetry of the fluid flow within the period, both in terms of fluid flow rate and in time. In the absence of a pressure drop at low frequencies of the oscillations of the piezoelectric element (of the order of the inverse relaxation time of the velocity), the period-average liquid flow rate is nonzero and increases with increasing frequency. In the presence of an external pressure drop along the layer, the average liquid flow rate is proportional to the pressure drop; at low frequencies, it is inversely proportional to the frequency; with increasing frequency, it reaches saturation. Based on the results of numerical modeling, various variants of new microfluidic technical devices generating a fluid flow using a piezoelectric bending actuator are proposed: a micropump creating a closed-circuit flow; fluid flow regulator and fluid volume dispenser.

Experimental evidence of liquid feeding during solidification of a steel

Sufficient liquid feeding under constrained solidification conditions like, those experienced in welding and casting, is vital to avoid solidification cracking. We present the results of unique in-situ experimental observations of liquid feeding in a solidifying steel melt pool. Liquid feeding was observed in the inter-cellular regions during the terminal stage of solidification. An average liquid flow speed of 450–500μms−1 was found. A pressure difference of the order of 104Pa is calculated to cause the liquid flow. The rate of solidification shrinkage and the rate of deformation were found to be less than the rate of liquid feeding.

Catalytic performance improvement of styrene hydrogenation in trickle bed reactor by using periodic operation

We investigated the catalytic performance improvement of styrene hydrogenation in a trickle bed reactor by using periodic operation. The effects of cycle period and split on relative conversion, which is defined as styrene conversion obtained from periodic operation over that from steady state operation, were examined at various operating conditions including gas and average liquid flow rates, pressure and temperature. The experimental results reveal that both cycle period and split have strong influence on the catalytic performance. The fast mode (short cycle period) is a favorable condition. The improvement by the periodic operation becomes less pronounced for operations at high average liquid flow rate, pressure and temperature. From this study, a maximum improvement of styrene conversion of 18% is observed.

Outdoor Prototype Results for Direct Atmospheric Capture of Carbon Dioxide

At Carbon Engineering, we have built a prototype air contactor with 10 m3 of packing volume, and have absorbed carbon dioxide from ambient air for over 1000hours of outdoor operation. Our prototype was built to: a) test our cross-flow, pulsed-liquid, PVC packing-based contactor design in an operational environment; b) to evaluate fan and liquid pumping energy requirements of our design; c) to assess technical and safety risks involved with liquid solution loss through entrained “drift” droplets, and; d) to examine for packing or solution fouling by atmospheric particulates. In this paper we present our results on the liquid pumping and fan energy requirements of our prototype, and show preliminary analyses we have conducted on liquid loss through “drift” droplets and NPE fouling.Our operation with pulsed liquid flow allows us to fully wet the surface of our structured packing with a brief period of full flow, then to cut flow for a duration of several minutes to let the liquid slowly react away as CO2 is absorbed. Using this technique we have cut average liquid flow to 10% of full manufacturer's specifications while retaining an average of over 80% of the capture rate observed at full flow. This method, under patent application, has allowed us to reduce our mgh fluid pumping energy requirement for the contactor to <40MJ/ton-CO2 (<11 kWh/ton-CO2). Here we report this energy requirement without accounting for pump efficiency, which we nominally assume to be ηpump=90%.Our prototype contactor has utilized high-performance XF12560 structured packing from Brentwood Industries (Reading, PA), manufactured from PVC rather than a stainless-steel. This choice has given us several advantages, chiefly that it costs far less on a per-surface-area basis, and that is provides a much lower pressure drop on a per- surface-area basis. We have previously shown data that suggests these plastic packings absorb CO2 with equal performance to traditional stainless-steel designs once wetted properly [1]. The high-performance and low pressure drop characteristics of our XF12560 product have allowed us to achieve PV work requirements of <350MJ/ton-CO2 (<100 kWh/ton-CO2). Again, this value does not reflect fan efficiency, which we commonly use as ηfan=55% in our analyses. This current value for PV work requirement is higher than we had previously reported, due to a specific cause of under-performance in our prototype which is discussed in this paper. Despite this, we are in fact very encouraged by the results of our first attempt at long-duration outdoor contacting, and we have numerous design improvements stemming from our prototype operation that will be included in the next iteration of our full-scale contactor design.Extensive air sampling was carried out during our contactor operation to measure the loss of liquid solution via “drift” droplets. During normal pulsed-flow contactor operation, 6 hour air samples taken from the contact outflow and measured for our K+ ion tracer, showed OH concentrations to be <5% of the OHSA regulated indoor respiratory requirement. After our 1000hours of integrated CO2 absorption time, we have as of yet been unable to observe any significant performance decrease in the absorptive properties of our working solution or in the efficiency of our structured packing product.

Quantification aspects of constant pressure (ultra) high pressure liquid chromatography using mass-sensitive detectors with a nebulizing interface

The present contribution investigates the quantitation aspects of mass-sensitive detectors with nebulizing interface (ESI-MSD, ELSD, CAD) in the constant pressure gradient elution mode. In this operation mode, the pressure is controlled and maintained at a set value and the liquid flow rate will vary according to the inverse mobile phase viscosity. As the pressure is continuously kept at the allowable maximum during the entire gradient run, the average liquid flow rate is higher compared to that in the conventional constant flow rate operation mode, thus shortening the analysis time. The following three mass-sensitive detectors were investigated: mass spectrometry detector (MS), evaporative light scattering detector (ELSD) and charged aerosol detector (CAD) and a wide variety of samples (phenones, polyaromatic hydrocarbons, wine, cocoa butter) has been considered. It was found that the nebulizing efficiency of the LC-interfaces of the three detectors under consideration changes with the increasing liquid flow rate. For the MS, the increasing flow rate leads to a lower peak area whereas for the ELSD the peak area increases compared to the constant flow rate mode. The peak area obtained with a CAD is rather insensitive to the liquid flow rate. The reproducibility of the peak area remains similar in both modes, although variation in system permeability compromises the ‘long-term’ reproducibility. This problem can however be overcome by running a flow rate program with an optimized flow rate and composition profile obtained from the constant pressure mode. In this case, the quantification remains reproducibile, despite any occuring variations of the system permeability. Furthermore, the same fragmentation pattern (MS) has been found in the constant pressure mode compared to the customary constant flow rate mode.

A long gas bubble moving in a tube with flowing liquid

The steady axisymmetric behavior of a long gas bubble moving with a flowing liquid in a straight round tube is studied by computationally solving the nonlinear Navier–Stokes equations using a Galerkin finite-element method with a boundary-fitted mesh for wide ranges of capillary number Ca and Reynolds number Re. As illustrated with a series of computed results, the hydrodynamic stresses due to liquid flow around the bubble tend to shape the middle section of long bubbles into a cylinder of constant radius, with a uniform annular liquid flow adjacent to the tube wall. But the surface tension effect tends to cause nonuniformities in the annular liquid film thickness. The annular liquid film thickness generally increases with increasing Ca, but decreases with increasing Re. In units of the bubble velocity relative to the tube wall, the average liquid flow velocity U ¯ is always less than unity, indicating that the bubble always moves faster than the average liquid flow. For convenient practical applications, a least-square fitted empirical formula is obtained in a form of U ¯ = 1 - A ∼ / ( 1 + B ∼ Ca - C ∼ ) with A ∼ , B ∼ , and C ∼ being functions of Re. The fact that the behavior of long bubbles moving in a tube appears independent of the bubble length is consistent with the inconsequential influence of the uniform annular film flow in bubble’s middle section to the bubble dynamics. Whereas all the long bubbles exhibit similar nose profile, various tail shapes can be obtained by adjusting the values of Re and Ca.

Trickle bed reactors: Effect of liquid flow modulation on catalytic activity

The effect of slow ON–OFF liquid flow modulation on the oxidation of aqueous solutions of ethanol using a 0.5% Pd / Al 2 O 3 commercial egg-shell catalyst was investigated in a laboratory trickle bed reactor (TBR). In this mode of operation, the catalyst was cyclically exposed to oxidative and reductive environments. The study was carried out under different gas and liquid flow rates, cycle periods and splits. Cycling results have been compared with the steady-state experiments performed at the corresponding average liquid flow rate. Significant improvements over the continuous operation were obtained when the catalyst was exposed to a short surplus of oxygen (to minimize deactivation by overoxidation in the kinetic regime) after a longer time of working in the mass transfer limited regime. According to the results presented here, it is recommended to work with high liquid flow rates and moderate gas flow rates to ensure complete wetting of the catalyst during the ON cycle and to minimize the overoxidation process during the OFF cycle.

Experimental investigation of fast-mode liquid modulation in a trickle-bed reactor

Unsteady-state operation of trickle-bed reactors (TBRs) is a promising technique to improve reactor performances especially when mass transfer phenomena are rate controlling. Among the different techniques, fast-mode modulation of the liquid flow rate seems to be one of the most successful. In fact cycling the liquid flow rate at very low frequencies can induce the reactor to work at the high-interaction regime where mass and heat transfer phenomena are strongly enhanced. Fast-mode periodic operation, then, can be considered an extension of the natural high-interaction regime at a mean range of gas and liquid flow rate normally associated with trickling regime in steady-state conditions. Experimental tests have been performed in a TBR employing α -methyl styrene hydrogenation on Pd/C catalyst in unsteady-state conditions by “on–off” fast-mode liquid modulation. Results have been compared with the steady-state experiments at the corresponding average liquid flow rate, revealing a conversion rate improvement up to 60%. All experiments have been performed in isothermal conditions, so conversion improvement can be ascribed only to mass transfer increase and not to thermal effects. The variation of gas and liquid flow rates and liquid cycle parameters presented several important implications about the optimal working conditions.

Experimental investigation of countercurrent liquid-vapor interactions and their effect on the friction Factor

An experimental test facility was constructed to determine the vapor flow influence on the friction factor of countercurrent liquid flowing in small channels. The fluids used were water and air. The friction factor for liquid flowing in three different grooves with channel angles of 20°, 40°, and 60° was evaluated to determine the influence of the vapor flow for a velocity range of 0–10 m/s. The vapor flow was shown to significantly influence the friction factor of the liquid, due to the frictional interaction at the vapor-liquid interface. As expected, increasing the velocity of the vapor flow resulted in an increase in the friction factor of the liquid. The amount of this increase was shown to depend on the ratio of the average vapor velocity to the average liquid flow velocity. For grooves with larger channel angles, the vapor flow velocity was shown to have a more significant influence on the friction factor of the liquid. The wave height at the liquid surface was also found to affect the friction factor, with larger waves resulting in an increased friction factor.