Suction Conditions Research Articles

Analysis of Processes Mechanized Oil Mining with the Methods Theory of Electrical Circuits

The authors investigate the problems of the development of the oil and gas complex at the last stage of operation, when oil is extracted by lifting. The main methods of lifting employed in the Russian Federation and the USA are described. A particular focus is placed on large water cuts at this stage of oil production. Literature on the issue under investigation is reviewed and the problem is set to analyze and construct models of oil production processes at the stage of well operation by lifting methods using network analysis (electrical circuits) in order to rationally manage all processes comprehensively. A typical flow chart of the oil production process by lifting methods is described. Technological processes of oil production are compared to processes in electric circuits. Thus the process of pumping purified formation water into injection wells by means of block cluster pumping units is similar to the process of recharging a battery using an electric power generator. The process of filling a production well with gas-liquid mixture displaced from the formation under pressure of injection wells is similar to the process of charging a capacitor from a battery, the process of lifting liquid from production wells using production pumps — to the process of discharging a capacitor on an active load. The simplified electrical diagram of a typical flow chart of oil production processes at this stage is given. Based on the given equivalent electrical circuit of technological processes, according to the laws of theoretical electrical engineering, models of the battery charging, capacitor charging and discharging processes are built. The table of correspondence of the parameters of technological and electrical circuits is presented on the basis of which the authors propose simplified models of the processes of pumping purified formation water into injection wells using unit cluster pumping stations, of filling a production well under pressure of the injection well, lifting liquid from production wells by means of suction pumps and conditions under which various operating modes of lifting processes are achieved.

Determining soil water characteristic curve of lime treated loess using multiscale structure fractal characteristic

Soil–Water characteristic Curve (SWCC) is meant to describe the mechanical behavior of unsaturated soil. The present paper focuses on the internal multi-scale microstructure of Xining untreated loess and lime-treated loess with the use of scanning electron microscopy (SEM) and image processing technique. A new SWCC model was presented based on the fractal dimension of pore size distribution. The SWCC of untreated loess was calculated from fractal dimension and fitted well with curve tested from Fredlund SWCC device. The SWCC of lime-treated loess was then calculated. Two curves of Xining untreated loess and lime-treated loess have been compared and reasons for the difference have also been discussed. The results indicate that the content of large pores in lime-treated loess decreased and the content of micro-pore increased. The bracket pores were changed into cement pores. The pore fractal dimension D of Xining untreated loess is 1.39 and the pore fractal dimension D of Xining lime-treated loess is 1.53. Air-entry value of untreated loess is 12.16 kPa, while lime-treated Loess—35.15 kPa. In transition region, matric suction of lime-treated loess was in the range of 35.15 kPa ~ 4000 kPa, while matric suction of untreated loess—12.16 kPa ~ 2600 kPa. The range of the transition region in lime-treated loess is larger than that in the loess, while in the range of saturation region, the reverse applies. Under the condition of the same matrix suction, the saturation of lime-treated loess is greater than that of untreated loess. In the residual region, the difference of SWCC of soil samples is small.

MHD Casson Fluid Flow over a Non-Linear Stretching/Shrinking Sheet with Suction and Slip Boundary Condition

A problem of steady laminar magnetohydrodynamic (MHD) Casson flow over a non-linear stretching/shrinking sheet with suction and slip boundary condition is considered. The governing nonlinear partial differential equations are transformed into a system of nonlinear ordinary differential equations using a similarity transformation. The transformed ordinary differential equations are then solved numerically using the bvp4c function in MATLAB software. Dual solutions are found for a certain range of the governing parameter. The effects of the suction parameter and the slip boundary condition on the skin friction and heat transfer coefficients as well as the velocity and temperature profiles are presented and discussed.

Applicability of Two-Parameter Turbulence Models to Simulation of the Interaction of Near-Wall Flows with Blowing and Suction on Permeable Surfaces

The applicability of two-parameter turbulence models to investigation of the impact of free-stream high-intensity turbulence on the characteristics of near-wall flow and heat- and mass-transfer in the steady-state and unsteady boundary layers under the conditions of blowing and suction through permeable surface sections is analyzed. The calculated results obtained in specifying a constant relative mass flow rate parameter in the cases of blowing and suction through permeable sections are compared with the experimental data. The mechanisms of the interaction of blowing and suction of a gas of homogeneous constitution with the flow on two permeable sections upstream and downstream of these sections in the near-wall zone of turbulent boundary layer are studied on the basis of numerical solutions. The calculated results obtained in specifying a time-dependent flow-rate parameter on two permeable surface sections are given.

Effects of Relative Humidity During Curing on Small-Strain Modulus of Cement-Treated Silty Sand

This study investigated the effects of relative humidity ( $$R_{h}$$ ) or total suction condition during curing on small-strain shear modulus (G0) of a cement-treated silty sand using free-free resonant frequency tests (FFR). The moduli were determined on samples cured at different suctions corresponding to three $$R_{h}$$ values of 7%, 75%, and 100%, in both unsoaked and soaked conditions. Soil–water retention curves (SWRCs), and unconfined compression strength (UCS) were also determined along with x-ray diffraction (XRD) analysis. The cement-treated SWRCs showed a much flatter slope than the non-treated ones, and the air-entry suction increased with cement content. The values of G0 increased with cement content and curing time. The highest modulus was achieved in 75% $$R_{h}$$ curing condition. The 7% $$R_{h} $$ condition resulted in a significant drop in modulus, even close to the non-treated G0 for the 2% cement case. At the same UCS value, the soaked cement-treated samples had higher modulus than the non-treated ones in the unsoaked condition, indicating that the effect of suction on modulus was smaller than the effect of cementation. XRD analysis revealed a greater availability of C3S in 7% $$R_{h}$$ curing condition at 7-day curing period suggesting that the hydration process was still not complete, which explained the decrease in G0 in this curing condition.

Triaxial test on water absorption compression of unsaturated soil and its soil-water-air-coupled elastoplastic finite deformation analysis

Triaxial tests and numerical simulations were conducted to determine the water absorption compression of unsaturated soil. In the triaxial tests, unsaturated silt specimens under the same initial condition were prepared and the processes of different suction reduction, isotropic consolidation, and exhausted-drained shearing were applied to the specimens. The numerical simulations used a soil-water-air coupled finite deformation analysis code with a newly incorporated elastoplastic constitutive model. The degree of saturation was introduced to the internal state variables of the yield function of the SYS Cam-clay model and a soil-water characteristic model with void ratio dependency. Then, the triaxial test was treated as an initial and boundary value problem, and the series of processes in the experiments were simulated using a single set of material constants and initial values. The new findings are as follows:1)The loading criterion and the classification of loading conditions considering change in saturation degree can be specified in the elastoplastic constitutive model for unsaturated soil.2)Water absorption compression behavior was observed in the experiments not only under suction reduction but also under constant suction condition. This water absorption compression under constant suction condition was explained as a saturation-increase behavior due to volume compression using the soil-water characteristic model with void ratio dependency.3)By considering the triaxial test as an initial and boundary value problem, the temporal change in the volume and the amount of water absorption/drainage were able to be reproduced.

Modeling and dual solutions for magnetized mixed convective stagnation point flow of upper convected Maxwell fluid model with second‐order velocity slip

In the present work, we have studied a numerical solutions of MHD stagnation point flow of nanofluid over a stretching/shrinking sheet with mass suction condition. We have used the upper convected Maxwell (UCM) fluid model for the development of momentum equation and utilized it to explore the characteristics of elasticity of this model. We used the Buongiorno nanofluid model to develop the equations for the present problem. The governing flow, energy, and concentration equations are changed into the ordinary differential equations by means of suitable transformation. The subsequent ordinary ones are solved numerically using bvp4c scheme in MATLAB. The combined results of buoyancy forces, double slip (first‐ and second‐order slip), and elasticity have been investigated, and the influence of various flow parameters such as Hartmann number, suction parameter, and stretching/shrinking parameter on the skin friction coefficient, local Nusselt number, Sherwood number, and streamlines is studied and exposed through graphs. It is found that mass suction parameter and elasticity of UCM fluid increase the range of buoyancy forces for the existence of dual solutions. Also, buoyancy force increases the range of stretching/shrinking parameter where solution exists.

Structural Behavior of Pipelines Buried in Expansive Soils under Rainfall Infiltration (Part I: Transverse Behavior)

Landslides, fault movements as well as shrink/swell soil displacements can exert important additional loadings on soil buried structures such as pipelines. These loadings may damage the buried structures whenever they reach the strength limits of the structure material. This paper presents a two-dimensional plane-strain finite element analysis of an 800 mm diameter water supply pipeline buried within the expansive clay of the Ain-Tine area (Mila, Algeria), considering the unsaturated behavior of the soil under a rainfall infiltration of 4 mm/day intensity and which lasts for different time durations (8, 15 and 30 days). The simulations were carried out using the commercial software module SIGMA/W and considering different initial soil suction conditions P1, P2, P3 and P4. The soil surface heave and the radial induced forces on the pipeline ring (i.e., Axial , Shear forces and bending moments ) results indicated that following the changes of suction the rainfall infiltration can cause considerable additional loads on the buried pipeline. Moreover, these loads are proportionally related to the initial soil suction conditions as well as to the rainfall infiltration time duration. The study highlighted that the unsaturated behavior of expansive soils because of their volume instability are very sensitive to climatic conditions and can exert adverse effects on pipelines buried within such soils. As a result, consistent pipeline design should seriously consider the study of the effect of the climatic conditions on the overall stability of the pipeline structure.

Buoyancy forces and activation energy on the MHD radiative flow over an exponentially stretching sheet with second‐order slip

AbstractThe current study explores the effects of second‐order slip and activation energy (AE) on the magnetohydrodynamic and radiative fluid flow caused by a surface with exponential stretching. The binary chemical reaction with mixed convection is considered in this physical model to discover the heat transfer phenomenon. The governing system of equations leads to a set of nonlinear ordinary differential equations by using scaling analysis. The transformed system is calculated computationally by using the most powerful Shooting procedure with the support of MATLAB software. The characteristics of various flow parameters on the governing flow field are exhibited pictorially and deliberated. The results revealed that the coefficient of heat and mass transfer upsurge with growing values of the second‐order slip parameter and skin friction coefficient has a reverse effect on the first‐order slip parameter. The thermal measure of the fluid in the presence of suction and slip conditions is seen to be lesser than that with the nonslip and nonsuction conditions. The heat measure of the fluid augments with the rising buoyancy parameter. The influence of slips coupled with AE is significant in the fluid flow and heat transfer characteristics. The outputs of the current investigation are validated by comparing the Nusselt number with the available results and are found to closely agree as a limiting case.

All-condition measuring methods for field performance of room air conditioner

Room air conditioners (RACs) are used worldwide and have become one of the major energy consumers in buildings. Because the actual field performance directly affects the energy consumption, the actual performance of an RAC must be determined. The compressor energy conservation (CEC) method exhibits better adaptability to the existing field test methods. However, the refrigerant mass flowrate cannot be calculated accurately under two-phase suction conditions, which is common for current high-energy-efficiency RACs. Therefore, two all-condition field measurement methods based on the CEC and compressor efficiency (CE) methods are proposed, and the isentropic and volumetric efficiency under wet compression working conditions is predicted with data-driven models trained using a back-propagation neural network (BPNN). The accuracy verification indicates that the relative errors of the refrigerant flowrate and cooling/heating capacities of both methods are approximately within ±15%, which is sufficient for the field performance evaluation; in addition, the CEC–compressor volumetric efficiency (CVE) method performs better. Furthermore, the proposed methods are compared, and the accuracy of the dynamic conditions is analyzed to improve the calculation performance.

Combined effect of compaction level and matric suction conditions on flexible pavement performance using construction and demolition waste

The characteristics of the unbound base layer have been recognized to influence the performance of flexible pavements to wide extents depending on climate conditions, construction quality, material source, traffic level, and pavement structure. Recently, unsaturated soil modeling has become generally accepted in predicting the pavement performance as pavement layers are typically placed well above soil water table, and tend to remain unsaturated during pavement service life. This paper investigates the combined impact of compaction level and initial matric suctions of construction and demolition (C&D) waste material used as a based layer on simulated pavement performance using the AASHTOWare Pavement ME Design software. Towards the preparation of the software inputs as per level 1 requirements, a laboratory experimental program was conducted on C&D material which includes the construction of soil water characteristic curve (SWCC) and determination of resilient modulus at four different moisture contents and two levels of compaction effort. The simulated pavement performance analyses consider two climatic conditions (dry and wet), two groundwater table levels (shallow and deep), two types of subgrade soil (strong and weak), and two thickness levels for the base and asphalt surface layers (thin and thick). Full statistical analyses of the main and interaction effects were performed on the results of AASHTOWare Pavement ME Design software. The results showed that the compaction level has more significant effect on the base and subgrade rutting and bottom-up fatigue cracking than the initial matric suction. In addition, both initial matric suction and SWCC input level were found to have a significant effect on all simulated distresses. Furthermore, the interaction between the compaction and initial matric suction was found to be significant.

Novel solution for heat and mass transfer of a MHD micropolar fluid flow on a moving plate with suction and injection

Two new functions on the semi-infinite interval, namely Rational Gegenbauer (R) and Exponential Gegenbauer (E) functions are proposed to solve the heat transfer problem. The considered problem is flow of MHD micropolar over a moving plate with suction and injection boundary conditions. For applying Tau method efficiently, two matrices of derivative and product for both of rational and exponential Gegenbauer whose enable us to solve a system of nonlinear algebraic equations on the semi-infinite interval were introduced, and an error bound of these functions approximation was estimated which led to have an exponential convergence rate in this method. Moreover, the influence of the important physical parameters on heat and mass transfer phenomena are studied with details. Comparing the results of Rational Gegenbauer Tau and Exponential Gegenbauer Tau methods with available analytical and numerical solutions shows that the present methods are efficient and have fast convergence rate and high accuracy. This method can solve a set of coupled nonlinear and high-order differential equations on a semi-infinite domain by converting to a set of linear equations.

Resilient and permanent deformation of unsaturated unbound granular materials under cyclic loading by the large-scale triaxial tests

The road base and subbase are normally situated above the underground water table and thus in the unsaturated state. To study the cyclic behavior of unbound granular materials (UGMs) in the road base and subbase courses under controlled matric suction conditions, a series of cyclic tests on the unsaturated UGMs were conducted by the large-scale triaxial apparatus. The large-scale triaxial apparatus was upgraded using an unsaturated module to control the matric suction by the axis-translation technique. Emphases were placed on the effects of matric suction and cyclic stress amplitude on the accumulated axial strain and resilient modulus of UGMs. Test results showed that the increase in matric suction reduced the development of accumulated axial strain exponentially under different cyclic stress amplitudes. Based on the shakedown theory, both the plastic shakedown and plastic creep limits were determined, which tended to grow linearly with the increase in matric suction. A new empirical model was proposed to predict the accumulated axial strain of unsaturated UGMs. Moreover, the increase in both matric suction and cyclic stress amplitude led to the increase in resilient modulus, and linear relationships existed between the resilient modulus and matric suction.

Effect of Suction and Discharge Conditions on the Unsteady Flow Phenomena of Axial-Flow Reactor Coolant Pump

In order to study the effects of the suction and discharge conditions on the hydraulic performance and unsteady flow phenomena of an axial-flow reactor coolant pump (RCP), three RCP models with different suction and discharge configurations are analyzed by computational fluid dynamics (CFD) method. The CFD results are validated by experimental data. The hydraulic performance of the three RCP models shows little difference. However, the unsteady flow phenomena of RCP are significantly affected by the variation of suction and discharge conditions. Compared with that of Model E-S (baseline, elbow-single nozzle), the pressure pulsation in rotating frame of Model S-S (straight pipe-single nozzle) and Model E-D (elbow-double nozzles) is weakened in different degrees and forms, due to the more uniform flow fields upstream and downstream of the impeller, respectively. It indicates that the generalized rotor-stator interaction (RSI) actually exists between the rotating impeller and all stationary components causing the circumferentially non-uniform flow. Furthermore, improving the circumferential uniformity of the flow upstream and downstream of impeller (suction and discharge flow) also contributes to reducing the radial dynamic fluid force acting on the impeller. Compared with those of Model E-S, the dynamic FX and FY of Model S-S are severely weakened, and those of Model E-D also gain a minor amplitude decrease at fBPF. In contrast, the general pressure pulsation in fixed frame is mainly related to the rotating impeller and barely affected by the suction and discharge conditions.

Total Artificial Heart Incorporating Novel Stacked Motor; First In Vivo Results

The latest version of the continuous flow total artificial heart (CFTAH), which incorporates a novel stacked motor to improve passive self-regulation of pressure difference between the left and right atria, and reduce pump rotor over-excursion, was tested in vivo in a calf model to assess operational performance. The CFTAH was implanted in a calf and run at various pump operating conditions including mean pump speeds from 2400 to 3600 RPM, sinusoidal speed modulations from 0 to 25%, and speed modulation rates from 80 to 120 B.M. It was also tested under various combinations of simulated high and low systemic vascular resistance and pulmonary vascular resistance via outlet graft clamping and administration of a Nitroprusside respectively. The CFTAH responded to all control inputs and ran as expected during the experiment. The head curves of the right and left pumps generated from measured pressures, measured right flow and calculated left flow, were consistent with in vitro data on this pump. The passive atrial pressure regulation performed well in the normal operating range, and there were no signs of excessive rotor axial displacement during extreme pressure excursions as had been seen in the previous versions of the pump. The left atrial pressure was unusually low throughout most of the experiment and we believe that this may have been due to partial blockage of the of the left inflow cuff proximal to the pressure line tap. This led to several left inlet suction conditions and extreme pressure conditions. The replacement of the standard, single stack stator motor with the new dual stator stack motor resulted in better passive regulation of the pressure difference between the left and right atria. Also, the extreme pressure conditions resulting from left inlet suction events did not cause the pump's rotor to rub against the volute housing as had been seen in previous versions of the pump. Even though the self-regulation was acceptable, shifting of the regulation characteristic to increase the nominal LAP-RAP value will improve the regulation further, and this modification will be implemented prior to the next in vivo experiment.

Thrombectomy aspiration device geometry optimization for removal of blood clots in cerebral vessels

A study involving the removal of blood clots in cerebral vessels by aspiration thrombectomy is presented. A robust design for the distal end geometry of a catheter is obtained that, together with adequate suction conditions, could avoid potential damage in the artery or fragmentation the thrombus. The optimization process of the parameters is undertaken by a Design of Experiments (DOE) that has been prepared based on Robust Design theories. In particular, 27 experiments are run for one factor at 9 levels (catheter geometry) and up to 9 factors at 3 levels. The experiments are formulated with virtual models that are solved with computing tools. Co-simulation between Computer Fluid Dynamics (CFD) and Finite Elements Method (FEM) structural analysis was used to obtain the suction conditions and the behavior of the blood clot during the intervention process. By comparing the results of the 27 experiments, the highest values of the suctioning force are obtained for a hole pattern based catheter design, that also gives the lowest risk for clot damage (based on the stress value obtained). Direct aspiration and designs based on conical catheter distal ends, give less robust solutions (results are not stable when the conditions of the environment change). Our study investigated the distance between the catheter and the clot, and it was noted that if the catheter was far from the clot, the suction generated a vessel narrowing and consequent potential damage. Up to 90 kPa could be applied when suctioning at a maximum distance equal to the diameter of the vessel between the distal end of the catheter and the proximal end of the clot. A maximum suctioning force of 0,514N was achieved without damage to the artery or the clot. This research enables us to determine and use the most representative parameters and geometries to be tested in in-vitro and in-vivo experiments. In this virtual study, hypothesizes are assumed with regard to the material properties, but the robustness of the design process allows to expect similar results in future in-vitro and in-vivo tests.

Modeling of blood clot removal with aspiration Thrombectomy devices

Thrombectomy by aspiration is a highly effective method of accomplishing vessel recanalization. This study aims to obtain a mathematical model that allows the prediction of the dynamic response of a thrombus in response to different suction conditions, in order to avoid potential damage or the breakage of the clot during the interventional procedure. Virtual computing models have been created using Bond-Graph data and mass-spring Multi-Degree of Freedom equations. The model allows the use of tensile and torsion loads that could potentially be generated by the suction pressure together with different catheter geometries. The stress generated in the clot depends on its length and on its stiffness. The results obtained with the mathematical model are validated with a Finite Element Method (FEM) model, shows good agreement in terms of stress and elongation values. The results are consistent with previous Bond Graph models which indicated that the forces needed to extract a blood clot from an artery in in-vitro experiments are within the range used experimentally (~40-90 kPa). Qualitative experiments are undertaken with 3D printed scale prototypes and gelatin. The results are consistent with Computer Fluid Dynamic (CFD) simulations.

Impact of Drying/Wetting on Shear Stiffness and Shear-Induced Volume Change Behaviours of Unsaturated Silty Clay

To further improve the understanding of the impact of drying/wetting on mechanical behaviours of unsaturated soils, this paper presented experimental results of suction-controlled triaxial tests on a slurry-consolidated silty clay with different drying/wetting cycles, matric suctions and net confining pressures. Test results show that, even if the same net confining pressure and matric suction were followed during triaxial shearing, the specimens that experienced six drying/wetting cycles (D–W-6) produced higher shear stiffness in the early stage of shearing and lower volumetric strain compared to those of specimens that have not been subjected to any drying/wetting history (D–W-0) at low matric suction condition. The stress–strain relationship of soils tends to alter from strain-hardening to strain-softening after drying/wetting. This is because the maximum matric suction experienced in drying/wetting process is similar to the pre-consolidation pressure, and thus the specimens became overconsolidated. However, D–W-6 shows a similar stress–strain relationship with D–W-0 under matric suction of 200 kPa due to the shear stiffness arisen from the irreversible volume compression (overconsolidation), which is counterbalanced by that contributed by its lower degree of saturation. The impact of drying/wetting on mechanical behaviours of unsaturated soils is always affected simultaneously by irreversible volume compression and lower degree of saturation. The overall influence of drying/wetting depends on the proportional effects of the two factors.

Tissue suction-mediated gene transfer to the beating heart in mice.

We previously developed an in vivo site-specific transfection method using a suction device in mice; namely, a tissue suction-mediated transfection method (tissue suction method). The aim of this study was to apply the tissue suction method for cardiac gene transfer. Naked plasmid DNA (pDNA) was intravenously injected in mice, followed by direct suction on the beating heart by using a suction device made of polydimethylsiloxane. We first examined the effects of suction conditions on transgene expression and toxicity. Subsequently, we analyzed transgene-expressing cells and the transfected region of the heart. We found that heart suction induced transgene expression, and that −75 kPa and −90 kPa of suction achieved high transgene expression. In addition, the inner diameter of the suction device was correlated with transgene expression, but the pressure hold time did not change transgene expression. Although the tissue suction method at −75 kPa induced a transient increase in the serum cardiac toxicity markers at 6 h after transfection, these markers returned to normal at 24 h. The cardiac damage was also analyzed through the measurement of hypertrophic gene expression, but no significant differences were found. In addition, the cardiac function monitored by echocardiography remained normal at 11 days after transfection. Immunohistochemical analysis revealed that CD31-positive endothelial cells co-expressed the ZsGreen1-N1 reporter gene. In conclusion, the tissue suction method can achieve an efficient and safe gene transfer to the beating heart in mice.

Recovery Characteristics of Weak Alkali ASP Flooding in Second Oil Reservoir

Taking two weak alkali ASP flooding test blocks as the research object, the injection-production characteristics, effective characteristics, agent recovery characteristics, reservoir inhalation condition, pressure characteristics and emulsification characteristics were analyzed. The results showed that the weak alkali ASP flooding had strong injection-production ability, high oil recovery rate, improved suction condition, established effective driving pressure system, obvious emulsification, and not serious chromatographic separation. The apparent inhalation index decreased by 23%-33%, and the liquid production index decreased by 31-42%; The inhalation thickness ratio were 89.5%-92.7%, and the water cut decreased by 16%-20%; The enhanced recovery increased by over 20% in the weak alkali ASP flooding of the second oil reservoir.