Pumping Conditions Research Articles

Numerical exploration of chalcogenide microstructured fiber for ultrabroadband supercontinuum generation of optical vortices

• A microstructured fiber is proposed which features a near-zero and flat dispersion of OAM 1,1 with variation between −14.53 to −0.19 ps/nm/km from 4000 to 10600 nm and a small confinement loss. • We summarized the regulation of chromatic dispersion variation of OAM mode and discussed the coherence of with different pump conditions. • Several OAM supercontinuum spectra spanning from 1.5 to 15 μm at −40 dB are obtained. The OAM 1,1 supercontinuum spectrum is the broadest coherent OAM supercontinuum spectrum we have seen. We propose a microstructured fiber with an AsSe 2 ring and two well-ordered air hole rings for supercontinuum generation of optical vortex modes. The fiber features a near-zero and flat dispersion of OAM 1,1 with variation between −14.53 to −0.19 ps/nm/km over a 6600 nm bandwidth from 4000 to 10600 nm and a small confinement loss of < 1 dB/m up to 14700 nm. A coherent supercontinuum spectrum of the vortex mode (OAM 1,1 ) is generated from 1550 to 14484 nm at −40 dB by launching a 100 fs pulse with 120 kW peak power into a 30 mm long microstructured fibers. The high-order OAM (l = 4) supercontinuum spectrum ranging from 1805 to 15022 nm can be generated by launching a 100 fs laser pulse with a peak power of 60 kW at 7.0 μm in the proposed fiber. We also discussed the influence of different noise levels, propagation distances and pumping powers on the coherence.

Comparison of a novel finite element method for sucker rod pump downhole dynamometer card determination based on real world dynamometer cards

• Evaluation of the downhole dynamometer card based on the finite elements method. • The novel advanced finite element method overcomes limitation of existing models and is based on physical parameters. • An excellent match with measured downhole dynamometer cards was reached. • The simulation results allow a the evaluation of the performance parameters of the sucker rod pumping system. An advanced dynamic finite element model is presented that diagnoses the downhole pump performance of sucker rod pumping systems, applicable for any pumping conditions and equipment used. The results are compared to downhole measurements and other state of the art evaluation techniques. Existing diagnostic tools exhibit specific limitations that reduce their applicability and output quality. This paper introduces a diagnostic tool, which can predict the rod string's stress field and its movement not only at the pump plunger but all along the rod string. Moreover, this tool can account for the interaction between rod guides and tubing as well as rod string and tubing. To this end, innovative tube-to-tube contact modeling is applied. The high precision results are accomplished by running a dynamic finite element simulation. The basic principle is to evaluate the plunger load incrementally by consecutively applying restarts of each time step, fully automated and computation time optimized. This publication shows that both the plunger load and the rod string's dynamic behavior can be determined for any given wellbore as long as the borehole trajectory and surface dynamometer measurements are known. The dynamic finite element model is evaluated for a deviated system and a vertical system equipped with two different downhole pump types. Comparing the simulation results with the available downhole measurements shows an excellent match. The the proposed solution provides a considerable amount of details about the overall system's behavior. The evaluation has shown that the performance of standard and novel downhole pump types can be successfully diagnosed in detail, which is just possible under limitations with commercial software solutions.. The novelty of the shown technique is the consideration of the full 3D trajectory, the implementation of only physical properties of the equipment used, and a realistic setup. The validation of the model output with measured downhole data indicates an excellent accuracy of the shown model.

Fuzzy system design for automatic irrigation of agricultural fields

One of the main challenges in arid and semi-arid regions is the lack of water for various purposes such as industrial and agricultural applications. The problem is even more significant in traditional agriculture. The geographical location, climatic conditions, average annual rainfall, vegetation, air pollution and turbidity, and canopy of plants are important and lead to different water consumption in plants. Therefore, proper water consumption in agriculture in most countries leads to food security and a better supply of crops. In this research, we propose a fuzzy system that has eight inputs and seven outputs. Inputs include soil moisture, relative humidity, air temperature, wind speed, soil permeability, daily rainfall, vegetation, and air pollution. The Fuzzy outputs are the reference and water stress evapotranspiration, water pump condition, duration of water pump operation, the volume of water requirements for crops, irrigation efficiency, and water losses. The main feature of the fuzzy system is the prediction of water consumption in different climates with high accuracy. To prove high efficiency and accuracy, we have performed many analyzes in various geographical locations. The geographical locations are tropical, semi-mountainous, and mountainous areas. In addition, we have performed three different analyses in four periods using our fuzzy system. In the first and second modes are used the average daily and hourly data, respectively. Finally, in the third mode, some data of the second method, such as the impacts of air pollution, soil moisture, vegetation, and water infiltration rate in the soil, are not considered because most of the proposed approaches do not consider the factors. The results show that the second mode is more efficient, and in some farms saves about 70% in water consumption. In addition, the results show that the water consumption in autumn and winter is lower than in spring and summer. The fuzzy system has high efficiency on all crops in different climates and can prevent water stress or waterlogging. It irrigates as much water as the plants need and prevents water loss. One of the main factors in increasing the accuracy of the fuzzy system is the use of vegetation level, soil moisture, air pollution, soil type, and plant canopy. The research results show that the proposed system can be used in different climates and significantly reduce water consumption in agricultural lands. Regression, correlation coefficient, and RMSE analysis have been used to validate the fuzzy system.

Heat effects modelling on the efficiency loss of the lubricating interface between piston and cylinder in axial piston pumps

This work presents a systematic analysis of the tribological properties of the lubricant and the thermal exchange effect on the deformation of the solid-fluid structure between the piston and cylinder block in an axial piston pump. A thermo-elastohydrodynamic model is established and used to study the pump. Fluid film properties, friction forces and leakage of the solid-fluid structure are calculated and analysed under normal operating conditions of the axial piston pump s. The friction and leakage losses representing the direct total power loss are analysed for different conditions. Furthermore, the thermal effects on the oil film properties and lubrication mechanisms are calculated and discussed. This work provides sufficient methods and processes to evaluate the causes of the lubrication failure. It proves that the effects of heat exchange in the energy loss and efficiency loss between piston and cylinder are critical. Finally, some suggestions are given for a better design of the axial piston pump.

Adaptive Control Strategy and Model of Gas-Drainage Parameters in Coal Seam

For a long time, the serious mismatch between negative pressure and drainage parameters of underground gas drainage has been the main reason for the standing engineering problems in coal mines, such as low gas drainage concentration, fast decay, and low-utilization rate. Aiming at these problems, an innovative method by adding micro-frequency conversion drainage pumps and electronically controlled valves at the key nodes of the conventional pipe network system of gas drainage and the joint quantitative regulation of underground regulation facilities and surface drainage pumps based on the intrinsic correlation between the drainage parameters and negative pressure is proposed in this paper to solve the difficulty of how to regulate increasing pressure or resistance in the on-site gas-drainage system and to realize energy matching in the whole drainage system on demand. For this method, the study further defines the safety and efficiency criteria of gas drainage, proposes the adaptive control strategy of gas-drainage parameters, and establishes the adaptive control model based on particle swarm optimization. The model took the safety and efficiency criteria of gas drainage as the constraint conditions and the maximum gas-drainage flow or concentration as the objective function to adaptively adjust the operating conditions of drainage pumps, micro-frequency conversion drainage pumps, and electric control valves to realize the adaptive regulation of gas-drainage parameters. Finally, based on the adaptive control strategy and model of gas-drainage parameters, the numerical simulation research was carried out through Comsol with Matlab. The results show that the gas-drainage concentration and high-concentration drainage period can be increased many times, and the adaptive drainage parameters of valves and micro pumps can be adjusted intelligently, which provides a theoretical basis for the intelligent field implementation of gas.

Injection locking and breathing soliton microcomb generation dynamics of a nonlinear optical microcavity-laser diode butt-coupled system with pump power much higher than the parametric oscillation threshold

This paper mainly analyzes the injection locking mechanism of pump laser diode and the breathing microcavity optical frequency comb (microcomb) generation dynamics of the nonlinear optical Kerr microcavity-laser diode butt-coupled system with resonant Rayleigh backscattering feedback. The nonlinear dynamics is especially studied under the condition of the laser diode pump power much higher than the parametric oscillation threshold of the four-wave mixing microcomb in nonlinear Kerr microcavity. Further, we find that under the condition of high-power pumping, the exact mechanism for the system to produce the breathing microcomb is not due to the self-injection locking of the lasing frequency of the laser diode main pump mode, but a newly discovered microcavity resonant excitation mechanism through the pump mode modulation sideband (caused by microcavity Rayleigh backscattering feedback), which is closely related to the breathing characteristics of the generated soliton microcomb.

Research on pressure pulsation characteristics of a reactor coolant pump in hump region

The reactor coolant pump (RCP) is the machinery used in nuclear power facilities to move coolant. So RCP operation must be safe in order for nuclear power plants to operate reliably. It was discovered throughout the experiment that the flow rate of RCP was unsteady between 0.875 Q0 and 0.85 Q0 and the pressure pulsation increased dramatically. As the flow drops, the head no longer increases, but instead declines. The condition of pump is in the hump region. This research conducts tests to determine the characteristics of pressure pulsation and uses numerical simulation to investigate the causes of increased pressure pulsation. According to the study, when the pump was working in hump region, the amplitude of low-frequency (<fr) pressure pulsation increase dramatically. The impeller's flow separation created vortices, which propagated downstream and caused stalls in the diffuser. The A_RMS of the low-frequency signal increases as a result of this.

Plasmonic distributed feedback lasing in an anodic aluminum oxide/silver/polymer hybrid membrane.

A hybrid membrane is employed as a high-order plasmonic distributed feedback (DFB) cavity to reduce the lasing threshold of polymer lasers. The hybrid membrane consists of an anodic aluminum oxide (AAO) membrane, a 25 nm thick silver layer and a free-standing polymer membrane. The AAO membrane is fabricated by a low-cost, single chemical etching method. Then, a layer of silver with a thickness of 25 nm is sputtered on the surface of the AAO. Subsequently, a polymer membrane is directly attached to the silver-plated AAO membrane, forming an AAO/silver/polymer hybrid membrane. Under optical pumping conditions, low-threshold, three-order DFB lasing is observed. The proposed laser device exhibited a dual-threshold characteristic because of the evolution from amplified spontaneous emission to DFB lasing. And a significant shift from omnidirectional emission to directional emission lasing can be observed while the pump energy density is beyond the second threshold. Furthermore, the plasmonic enhancement sourced from silver corrugation reveals important improvement effects to the DFB lasing of AAO/silver/polymer hybrid membrane for decreasing threshold, narrowing full width at half maximum (FWHM), and an increasing Q factor. This work may promote the design and production of low-cost and large-area high-order plasmonic DFB polymer lasers.

Water Masers as an Early Tracer of Star Formation

We present a study of the correlation between 22 GHz water maser emission and far-infrared/submillimeter (IR/sub-mm) sources. The generalized linear model (GLM) is used to predict H2O maser detection in a particular source with defined physical parameters. We checked the GLM predictions by observing a sample of selected sources with the Effelsberg 100 m telescope. In total, 359 sources were observed. H2O masers were detected in 124 sources, with 56 new detections. We found 22 sources with a significant flux variability. Using the GLM analysis, we estimate that 2392 ± 339 star formation regions (SFRs) in the Galaxy may harbor H2O masers detectable by single-dish observations at the noise level of ∼0.05 Jy. Analyzing the luminosity-to-mass ratio (L/M) of the ATLASGAL and Hi-GAL clumps associated with different maser species, we find that 22 GHz water masers have significantly lower values of L/M in comparison to 6.7 GHz class II methanol and 1665 MHz OH masers. This implies that 22 GHz water masers may appear prior to 6.7 GHz methanol and OH masers in the evolutionary sequence of SFRs. From the analysis of physical offsets between host clumps and maser interferometric positions, we found no significant difference between the H2O and class II methanol maser offsets against the host clump position. We conclude that the tight association between water masers and IR/sub-mm sources may provide insight into the pumping conditions of these masers and the evolutionary stages of their onset.

Impacts of Fracture Roughness and Near-Wellbore Tortuosity on Proppant Transport within Hydraulic Fractures

For unconventional reservoir hydraulic fracturing design, a greater fracture length is a prime factor to optimize. However, the core observation results from the Hydraulic Fracturing Test Site (HFTS) show that the propped fractures are far less or shorter than expected, which suggests that the roughness and tortuosity of hydraulic fractures are crucial to sand transport. In this study, a transport model of sands is first built based on experimental measurements on the height and transport velocity of the sand bank in fractures with predetermined width and roughness. The fracture roughness is quantified by using the surface height integral. Then, three-dimensional simulations are conducted with this modified model to further investigate the impact of tortuous fractures on sand transport, from which a regression model is established to estimate the propped length of hydraulic fractures at a certain pumping condition. The experiment results show that the height of the sand bank in rough fractures is 20–50% higher than that in smooth fractures. The height of the sand bank decreases with the reduction in slurry velocity and increases with the increase in sand diameter. Sand sizes do little effect on the transport velocity of the sand bank, but the increase in slurry velocity and sand volume fraction can dramatically enhance the migration velocity of the sand bank. The appearance of tortuous fractures decreases the horizontal velocity of suspended particles and results in a higher sand bank compared with that in straight fractures. When the sand bank reaches equilibrium at the tortuous position, it is easy to produce vortices. So, there is a significant height of sand bank change at the tortuous position. Moreover, sand plugging can occur at the entrance of the fractures, making it difficult for the sand to transport deep into fractures. This study explains why the propped length of fractures in HFTS is short and provides a regression model that can be easily embedded in the fracturing simulation to quickly calculate dimensions of the propped fractures network to predict the length and height of propped fractures during fracturing.

Influence of Inlet Groove on Flow Characteristics in Stall Condition of Full-Tubular Pump

The full-tubular pump is a new type of pump with a narrow range of stable operation. In order to improve the internal flow characteristics of the full-tubular pump under small flow conditions and improve the safe and stable operating range of the pump, this paper conducts numerical simulation of the full-tubular pump model based on the Reynolds time-averaged N-S equation and the SST k-ω turbulence model. The improvement mechanism of the parameters of the inlet grooves on the stall area of the full-tubular pump is studied, and the reliability of the numerical simulation of the full-tubular pump is verified by model tests. The research results show that the inlet groove can improve the head and efficiency of the full-tubular pump in the small flow area, and the head at the deep stall condition is increased by nearly 1.61 m. The inlet groove increases the pressure difference of the impeller, which increases the head and improves the hump. At the same time, the increase in the pressure difference of the impeller increases the backflow flow in the gap between the stator and the rotor. The groove can reduce the vortex strength and backflow range at the inlet pipe wall near the stall operating, and also improve the flow field at the impeller inlet. In terms of pressure pulsation, the groove can effectively suppress the low-frequency pressure pulsation at the inlet of the impeller of the full-tubular pump under stall conditions, and effectively reduce the amplitude of the main frequency pressure pulsation and improve the internal flow. The research in this paper can provide a reference for improving the flow characteristics in the stall condition of the full-tubular pump.

Thermal-hydraulic performance of additively manufactured lattices for gas turbine blade trailing edge cooling

• Thermal-hydraulic performance of four lattice frame materials, namely, Octet, Tetrakaidecahedron, Face diagonal-cube, and Cube is studied for turbine edge cooling application. • Face diagonal-cube provided the highest heat transfer coefficient and pressure drop values amongst the investigated samples at similar porosity values and unit cell size. • Cube topology yielded the lowest flow losses and consequently highest thermal–hydraulic performance of ∼ 2.78 at the lowest investigated Reynolds number. Gas turbine blade trailing edge cooling is challenging because of the stringent geometrical constraints driven by aerodynamics and thermal stresses. The blade topology becomes significantly thin towards the trailing edge which leaves a narrow room for the construction of internal cooling channels and also makes this section susceptible to failure due to thermal stresses. Conventionally, pin-fins are employed in the internal cooling channels of the trailing edge because they provide high levels of heat transfer coefficient values and also structural integrity. Much of the past studies on pin fins have focused on their relative arrangements, heights, crossflow scheme, etc., with an aim to enhance the endwall heat transfer coefficient as well as leverage the conjugate heat dissipation capabilities of these “extended surfaces”. Lattices on the other hand, have been investigated to a lesser degree, and some studies can be found for blade mid-chord region, however, with their manufacturability challenges at that time, the concepts did not gain traction. Lattices are far more complex topologies with superior local heat transfer characteristics as well as high conjugate heat dissipation capabilities due to large wetted surface area. With the recent advancements in metal additive manufacturing, complex topologies such as lattices can be revisited due to high chances of their realization now. To this end, we are presenting our study on lattices additively manufactured in 420 Stainless Steel (thermal conductivity nearly twice of Inconel 718), where four different unit cell topologies, (a) Octet, (b) Tetrakaidecahedron, (c) Face diagonal-cube, and (d) Cube, were printed using Binder Jetting technology. The aim of this study is to characterize the conjugate heat transfer capabilities of these lattices manufactured in 420 Stainless Steel prior to conduct similar study with Inconel 718, due to relatively simpler additive manufacturing route of Binder jetting (420 stainless steel) compared to Direct Metal Laser Sintering (Inconel 718). The intended design porosity of the samples was 0.886 and the coupons had single unit cell (edge size of 10 mm) in the thickness. The steady-state experiments were conducted to evaluate the effective thermal conductivity and forced convective heat transfer performance. For forced convection, the experiments were conducted for a wide range of Reynolds numbers with air as the working fluid. Overall heat transfer coefficient, pressure drop, Nusselt number and friction factor enhancement level and pumping power requirements of these structures are presented. The implications of the porosity variation due to manufacturing process on the interpretation of relative performance trends is discussed. The effective thermal conductivity was independent of the topology for considered porosity value. Face diagonal-cube yielded the highest heat transfer and pressure drop for the investigated Reynolds number range. However, Cube provided the best overall thermal hydraulic performance value of 1.94 to 2.78 for the investigated range of Reynolds number. At fixed pumping power conditions, Cube was capable of providing the highest heat transfer coefficient.

Optimization of pumping conditions in end pumped Tm: YAP lasers with the consideration of thermal effects

Optimization of pumping conditions in end pumped Tm: YAP lasers with the consideration of thermal effects

1.7 &amp;lt;bold&amp;gt;&amp;mu;&amp;lt;/bold&amp;gt;m self-synchronized picosecond pulsed random Raman fiber laser

Aiming at the structural complexity of the current 1.7 μm band short pulse lasers, we propose and implement a self-synchronized picosecond pulsed random Raman fiber laser. The half-open Raman cavity based on random distributed feedback is pumped by a 1 578 nm pulsed fiber laser to achieve a picosecond pulse output with a central wavelength of 1 695 nm and an average power of 224 mW. The composite cavity formed by distributed Rayleigh scattering automatically satisfies the synchronous pumping condition without the need for precise matching of cavity length or complex feedback control in the system. By inserting a wavelength division multiplexer in the cavity, the random sub-cavity noise is suppressed and the stability of the output pulse is improved. To the best of our knowledge, this is the first realization of a random pulse fiber laser operating at 1.7 μm, which can be widely used in bioimaging and material processing. <fig fig-type="abstract-image" id="F1" orientation="portrait" position="float"><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="1000-2618-2022-39-4-363/7A9ED982-4F80-49df-B290-3AA8759A767B-F001.jpg"/></fig>

Optimization of the Radiation Response of Backup Optical Fiber Amplifiers for Space Missions

We investigated the X-ray radiation impact on the performances of “backup” erbium-doped fiber amplifiers (EDFAs) and erbium-ytterbium-doped fiber amplifier (EYDFA). These devices are exposed to the space radiation constraints, unpowered in the “OFF” mode, up to their hypothetic activation during the mission. This atypical profile of use must be considered as it could lead to a higher radiation vulnerability. To carry out this study, active optical fibers differing in terms of radiation hardness have been exposed to steady-state X-rays under different profiles of amplifier use: the gain degradation is measured by varying the pumping conditions, that drive the photobleaching (PB) phenomenon, during the radiation exposure: “ON” (100% ON), “OFF” (0% ON), and “OFF–ON–OFF” with powering 2% or 10% of the time. Our results show that the impact of the pump and its related PB efficiency depend on the selected active fiber to build the amplifier. An important result is that the “backup” EDFA designed with radiation-hardened Ce-doped fiber does not suffer from an extra-degradation due to the “OFF” mode, contrary to the one designed with a nonrad-hard fiber. For this latter one, it is indeed possible to reduce the extra-gain degradation by powering the amplifier for short time periods during the “OFF” state; otherwise, the EDFA recovers this extra-gain degradation in a few hours after turning “ON” in our test conditions. For the tested radiation-tolerant EYDFA, an enhanced vulnerability is observed for the “OFF” amplifier, that can be reduced too by briefly powering the amplifier. The origins of these effects are discussed based on the properties of point defects related to the aluminosilicate (EDFA) and phosphosilicate (EYDFA) glasses of the fiber.

Predictive Maintenance Model Based on Multisensor Data Fusion of Hybrid Fuzzy Rough Set Theory Feature Selection and Stacked Ensemble for Fault Classification

With the rising demand for integrated and autonomous systems in the field of engineering, efficient frameworks for instant detection of performance anomalies are imperative for improved productivity and cost-effectiveness. This study proposes a systematic predictive maintenance framework based on the hybrid multisensor fusion technique of fuzzy rough set feature selection and stacked ensemble for the efficient classification of fault conditions characterised by uncertainties. First, a feature vector of time-domain features was extracted from 17 multiple sensor signals. Then, a comparative study of six different Fuzzy Rough Set Feature Selection (FRFS) methods was employed to select the various combinations of optimal feature subsets for various faults classification tasks. The determined optimal feature subsets then served as inputs for training the stacked ensemble (ESB(STK)). In the ESB(STK), Support Vector Machine (SVM), Multilayer Perceptron (MLP), k -Nearest Neighbour ( k -NN), C4.5 Decision Tree (C4.5 DT), Logistic Regression (LR), and Linear Discriminant Analysis (LDA) served as the base classifiers while the LR was selected to be the metaclassifier. The proposed hybrid framework (FRFS-ESB(STK)) improved the classification accuracy with the selected combinations of optimal feature subset size whiles reducing the computational cost, overfitting, training runtime, and uncertainty in modelling. Overall analyses showed that the FRFS-ESB(STK) proved to be generalisable and versatile in the classification of all conditions of four monitored hydraulic components (i.e., cooler, valve, accumulator, and internal pump leakage) when compared with the six base classifiers (standalone) and three existing ensemble classifiers (Stochastic Gradient Boosting (SGB), Ada Boost (ADB), and Bagging (BAG)). The proposed FRFS-ESB(STK) showed an average improvement of 11.28% and 0.88% test accuracies when classifying accumulator and pump conditions, respectively, whiles 100% classification rates were obtained for both cooler and valve.

Online Flow Estimation for Condition Monitoring of Pumps in Aircraft Hydraulics

Hydraulic systems in conventional civil aviation are currently monitored in a very rudimentary way. Normally, measured values are compared with a fixed threshold. If these measured values are outside the predefined limits, the entire hydraulic system is usually shut down. To overcome this deficit, a study regarding a novel prognostic health management method for aircraft hydraulic pumps, which allows a statement about the pump condition, is presented in this paper. The method is based on measuring differential pressure and temperature at a suitable resistance. In the first part of the study, the overall concept for monitoring the motor pump unit is analyzed. This is followed by a discussion of possible measurement methods and suitable resistors to determine the condition of the pump. In the second part of the study, the implementation for online monitoring of the pump is discussed. After a suitable approximation is found, the quality of the proposed method is evaluated with real hydraulic power generation and consumers.

Analysis of Surface Pressure Pulsation Characteristics of Centrifugal Pump Magnetic Liquid Sealing Film

In order to discuss the surface pressure pulsation characteristics of the magnetic-fluid sealing membrane of centrifugal pump, this paper studies the surface pressure pulsation characteristics of the shaft end sealing membrane under different flow operating conditions of centrifugal pump based on the combination of numerical calculation and experimental verification. The results show that the pressure value on the surface of the magnetic-fluid sealing film decreases with the increase of the flow rate of the centrifugal pump, and the pressure on the surface of the magnetic-fluid sealing film has periodic pulsation, and the period is the time required for a single blade to sweep the volute separating tongue. In one rotation cycle of the runner, the number of reciprocating movements of the magnetic-hydraulic sealing film is the same as the number of blades of the runner. The main reason for the pressure pulsation is that the impeller periodically sweeps the fixed surface of the centrifugal pump.

Inter-stage energy characteristics of electrical submersible pump under gassy conditions

Owing to the complex operational conditions of deep-sea or underground, the energy and flow characteristics in the electrical submersible pump (ESP) conditions are even more chaotic under gas-liquid flow, which degrades the energy conversion efficiency. At present, few studies have been carried out to demonstrate the difference between stages of ESP under gassy conditions. In this study, based on the Eulerian–Eulerian inhomogeneous model, an ESP with three stages was simulated to investigate the inter-stage differences in energy characteristics and flow patterns under both pure water and gas-liquid two-phase flow in detail. The simulation results are in good agreement with the experimental data. Gas phase distribution, external and internal characteristics in the ESP with three stages were analyzed at different flow rate with inlet gas volume fraction (IGVF) of 5%, 10%, and 15%. With the rise of IGVF, the degree of gas aggregation in the impellers and diffusers increases significantly, and the influence of the vortex formed by the gas concentration expands, and the differences vanish in gas distribution and flow trajectory between different flow channels. The proportion of gas in the flow channel is negatively correlated with the flow rate. Meanwhile, the variation law of head and efficiency under different inlet gas content conditions is fitted to the equation. The gas distribution pattern became further chaotic as the number of stages increases. The turbulence kinetic energy in the impeller is highly consistent with the gas aggregation pattern in terms of position distribution and change trend. At designed and best efficiency flowrate, the volume average of turbulence kinetic energy inside the second and third impeller is significantly higher than the first impeller. Overall, this study comprehensively reveals the gas phase distribution pattern, energy and internal flow characteristics in the ESP, which is helpful for the optimization design of such a pump and the improvement of the energy conversion efficiency under gassy condition.

Hydrodynamic Simulation of the Influence of Injection Flowrate Regulation on In-Situ Leaching Range

Reasonable control of the leaching range is one of the critical indicators of the in-situ leaching uranium mining process. However, there is currently no mature control technology. To verify and improve the current control technology of the leaching range in the industry, this work proposes an injection control mode for a small flow around the well-site and establishes a hydrodynamic model of the leaching range under eight different pumping and injection conditions by using the groundwater modeling system (GMS). The model calculation, range prediction, comparative analysis, and on-site SO42− and S isotope verification tests were carried out. Results show that with the change of liquid injection ratio, the area ratios of fixed pumping injection ratio (total pumping flowrate is greater than 0.3% of the total injection flowrate) and model leaching range under four pumping injection equilibrium conditions were 99.10%, 99.99%, 98.30%, and 97.95%, respectively. The farthest migration distance ratios of the leaching solution were 99.37%, 100%, 98.02%, and 97.58%, respectively. It is considered that the operation mode with a fixed pumping injection ratio has no noticeable control effect on the leaching range; selecting a reasonable proportion to regulate the flowrate of injection wells at different positions can effectively reduce the area of the groundwater flow field and realize the effective control of the leaching range. The research results are conducive to saving a lot of evaporation pool construction, land acquisition, human and material resource investment, and environmental policy pressure.