Water Piston Research Articles

Hybrid Hydrogel-Magnet Actuated Capsule for Automatic Gut Microbiome Sampling.

Non-invasive, pill-sized capsules can provide intestinal fluid sampling to easily retrieve site-specific gut microbiome samples for studies in nutrition and chronic diseases. However, capsules with both automatic sampling and active locomotion are uncommon due to limited onboard space. This paper presents a novel hybrid hydrogel-magnet actuated capsule featuring: i) pH-responsive hydrogels that will automatically trigger fluid sampling at an environmental pH of 6 and ii) active locomotion by an external rotating magnetic field. Two capsule designs were fabricated (Design A: 31 μL sampling volume with dimensions 8 mm × 19 mm, Design B: 41 μL sampling volume with dimensions 8 mm × 21 mm). They were immersed in simulated gastric (pH = 1.2) and simulated intestinal fluid (pH = 6.8) to test for automatic intestinal fluid sampling. An external rotating magnetic field was applied to test for active locomotion. Finally, seal tests were performed to demonstrate sample contamination mitigation. Preliminary experiments showed that sampling occurred quickly and automatically in simulated intestinal fluid at 6-15 hours, active locomotion via rotation, rolling, and tumbling were possible at magnetic field magnitudes 10 mT, oil piston seals were better at mitigating sample contamination than water piston seals, and minimum o-ring seal pressures limits of 1.95 and 1.69 kPa for Design A and B respectively were sufficient against intra-abdominal pressures. This work presents the ability to impart capsule multi-functionality in a compact manner without onboard electronics or external triggering for sampling.

Experimental Stand for Very-Low-Velocity Gas Flow Generation.

This article presents an experimental stand for the generation of gas flows with very low velocities. The constant volume air flow was generated in the measurement area with the use of a Mariotte bottle and a water piston (water column in a tank). The air-flow velocity was determined from the change in the height of the water piston with time, which was measured via the difference between the pressure above the water surface and the pressure at the bottom of the water column. The tests were carried out in the mean velocity range of 0.35-66 cm/s. The five different velocities of air flowing out of the measurement pipe, measured with the particle image velocimetry method were compared with the results from the water piston method. The differences did not exceed 7%.

Dynamic failure analysis of static seals under pressure fluctuation in an ultrahigh-pressure water piston pump

For ultrahigh-pressure piston pumps, in the reciprocating action of the piston, the fretting between the static face seal and the mating surface occurs with the change of the pressure in the piston chamber. This phenomenon will seriously affect the service life of the seal ring and lead to the failure of the pump. However, the failure of static seals used to seal ultrahigh-pressures is usually studied from the directions of shear, stress, or rubber material. These studies cannot explain the failure phenomenon of the sealing ring found in our experiment. This paper analyzed the failure of the face seal ring in a piston pump with a maximum pressure of 120 MPa. A two-dimensional axisymmetric finite element model was established based on the Mooney-Rivlin constitutive relation of the rubber material, and the fretting conditions of the sealing ring were analyzed. Combined with the wear scars observed by the scanning electron microscope the face seal ring’s dynamic failure mechanism on the ultrahigh-pressure piston pump was determined. A better sealing scheme was proposed and verified by the duration test of the pump, which provided a basis for the design of the sealing of the ultrahigh-pressure fluid with high-frequency fluctuations.

Fluid-dynamic analysis of an in-line water piston pump

The paper focuses on the analysis of inline water piston pumps, by means of simulation of the fluid-dynamic behaviour and experimental characterization. These pumps are commonly used on the car wash systems, industrial washes systems and fire protection systems. They possess a robust architecture, made of a typical rod-crankshaft mechanism, which transforms the circular motion of the pump shaft in the reciprocating displacement of the piston. The pump analyzed in the paper, in particular, moves three pistons, shifted one another of 120°; each piston sucks from a tank and delivers water to a hydraulic line via automatic, spring loaded, poppet valves. The shaft, rod and other movable components are lubricated with mineral oil; the three ceramic pistons are isolated from this environment using opportune seals and work with water. This pump is robust and durable but suffers of some problems: the instantaneous pressure trend within each piston is ideally a square wave: the pressure is equal to the tank pressure during suction, while it is equal to the delivery pressure during the delivery phase. Instead, non –ideal behaviour of the poppet valves, leakages, fluid properties make the pressure trend more critical: during the pressure transient between the two high and low levels, pressure peaks and de-pressurization till aeration and cavitation occurrence may happen. These phenomena generate vibrations and noise and can damage the pump components. In order to study this, a lumped parameter fluid dynamic model of the pump has been realized, later compared with experimental results coming from the test rig to validate it. The model has been used to explore the dynamic pump behaviour in several operating conditions (various speed values and delivery pressure levels), calculating the flow irregularity, the pressure and forces instantaneous trends. The design characteristics of the poppet valves have been explored, in particular the spring characteristics, to discuss the trend of the previous variables.

Doctrines vs. Realities in Reservoir Engineering

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 185633, “Doctrines and Realities in Reservoir Engineering,” by Euthymios Vittoratos, Petroprognostica, and Anthony Kovscek, SPE, Stanford University, prepared for the 2017 SPE Western Regional Meeting, Bakersfield, California, USA, 23–27 April. The paper has not been peer reviewed. The appreciation of empirical realities permits the improvement of commercial depletion planning and enables a greater number of projects. The concepts articulated here are applicable in almost all heavy-oil reservoirs and may be applicable also for lighter oils that possess oil chemistry typical of heavier oils (e.g., high acid content). This paper reviews the evidence for and against three doctrines in current use to develop depletion plans: (1) optimal recovery is obtained using a voidage-replacement ratio (VRR) of unity, (2) the Buckley-Leverett (BL) formulation (phase slippage) applies uniformly to heavier oils, and (3) viscous fingering dominates unstable multiphase flows. VRR=1 Doctrine: Optimal Waterflood Response Occurs With VRR=1 Reality: Periods of VRR<1 Increase Oil Recovery Though initially viewed with some suspicion, waterflooding has demonstrated multifold greater recovery than primary depletion for many reservoirs. It is, by far, the most important oil-recovery process. One visualization of the process is that of a leaky, deformable water piston displacing a fraction of the oil to the production wells. Maximum recovery occurs when the voidage created by the produced fluids (oil plus water) at reservoir conditions (pressure and temperature) is replaced fully by an equal volume of the injected water also at reservoir conditions (i.e., the waterflood VRR=1). In this way, reservoir pressure is maintained. The waterflood initial production is pure oil until water breakthrough. Subsequently, water is produced along with the oil, resulting in an increasing water/oil ratio (WOR). This simple visualization is intuitively attractive and has dominated the thinking of the industry. This “leaky, deformable piston” visualization is simplistic and neglects or sidelines complex physical and chemical properties of the reservoir. If the waterflood is operated below the oil bubblepoint pressure through a continued VRR<1, a gaseous phase forms, creating three-phase-flow conditions and more-complex displacement possibilities. Furthermore, reservoir oils can have widely different physical and chemical properties, varying by many orders of magnitude in viscosity and substantially in interfacial activity as described by metrics such as the total acid number. Despite the full recognition of these complications, over time, the now al-most universal practice developed of operating waterfloods with VRR=1. Analytical and Numerical VRR Simulations. VRR<1 activates many recovery mechanisms. Some mechanisms can be enumerated and examined, and others may exist that are yet to be identified. What is the possible upside of operating a waterflood with VRR<1? Making a rough estimate is not too difficult if we limit the number of mechanisms. With VRR<1, two dominant recovery mechanisms exist, solution-gas drive (VRR=0) and water displacement (VRR=1). As a first approximation, at an intermediary VRR<1, the two mechanisms may be additive: Oil Recovery (at Optimal VRR)=Oil Recovery by Pure Waterflood (VRR=1)+Pure Solution-Gas Drive (VRR=0).

Numerical Analysis of the Water Film Characteristics in the Eccentric State of a Radial Piston Pump

This paper investigates the working efficiency and reliability of a piston pair of radial piston pumps by accurately calculating the shape and pressure distribution of the piston pair. First, a leakage model of the piston pair is established based on the equivalent liquid resistance and adaptive eccentricity. This model considers the piston micro-motion in the cylinder and the force balance. Then, the piston clearance shape and pressure distribution are numerically simulated using a genetic algorithm and the finite-volume method, and the clearance leakage flow is discussed. The example analysis demonstrates the accuracy of the model; the iterative algorithm has good numerical stability at the given precision and can rapidly converge to the global optimal solution of the model to obtain the real-time piston eccentricity state and pressure distribution with high accuracy. The results demonstrate that the model has high accuracy. Finally, the effects of various parameters such as the piston diameter, initial clearance of the piston pairs, and piston speed on the leakage rate are discussed. The conclusions of this paper provide guidance for the design of water piston pumps.

Evidence of methane and carbon dioxide migration to the near surface zone in the area of the abandoned coal mines in Wałbrzych District (Lower Silesian Coal Basin, SW Poland) based on periodical changes of molecular and isotopic compositions

The objective of this paper is to determine the reasons, origin and character of periodical changes of methane and carbon dioxide concentrations in the near-surface zone as well as emission of these gases to atmosphere after closing bituminous coal and anthracite mines in the former Wałbrzych Coal District (SW Poland). The measurements were performed during the period including the active impact of “water piston effect” on the migration of a coal-bearing gases as well as the period of stabilization of water table of the Pennsylvanian aquifer. In the years 1997–2005, 20 sampling sessions were completed during which 3210 soil gas samples were collected at a depth of about 1.2m and along 4 measurement lines located in the Gorce and the Sobięcin depressions. Maximum methane and carbon dioxide concentrations measured in soil gas samples reached 32.4 and 15.7vol%, respectively. Isotopic study shows that coal-bed gases, recent microbial methane, and multigenetic carbon dioxide from degassing of ground-waters of the Upper Pennsylvanian aquifer occur within the near-surface zone of the Wałbrzych Coal District. Within the Serpukhovian Wałbrzych and Upper Bashkirian-Moscovian Žacleř coal-bearing formations three genetic types of coal-bed gases occur: Variscan thermogenic (methane, higher gaseous hydrocarbons and carbon dioxide), endogenic (abiogenic) carbon dioxide and “late” (Late Cretaceous) and recent microbial methane and carbon dioxide. Changes of mean concentrations of methane and carbon dioxide in the near-surface zone recorded during years of studies demonstrated the influence of “water piston effect”, which drives migration of coalbed gases towards the earth surface. In both the Gorce and the Sobięcin depressions, gas migrates with various intensity. Generally, the lower methane emission measured in the years 2004–2005, and compared with the period 1999–2000, resulted from the stabilization of groundwater table whereas higher carbon dioxide emission confirms the degassing of shallow groundwaters. Anomalous concentrations of methane and carbon dioxide were related to numerous faults and fracture systems cutting the steeply dipping Upper Mississippian and Pennsylvanian coal-bearing formations, and to the outcrops of these rocks. However, in the near-surface zone, multiproportional mixing of coal-bed gases, recent microbial methane and carbon dioxide is observed. Periodical changes of stable carbon isotope composition of methane and carbon dioxide of near-surface zone in particular sessions are caused by the time-related change of location of water table of Pennsylvanian aquifer in the complicated structure of the Gorce and Sobięcin depressions. Persistently anomalous concentrations of methane and carbon dioxide in the near surface zone, still observed after several-years-long stabilization of groundwater table, seem to indicate a continuous supply of coalbed gases to the near-surface zone through pervious dislocations. Such an interpretation is confirmed by the extreme value of methane emission detected at a particular sampling site after the cessation of the “water piston” effect. It was presumably caused by the secondary intensification of gas flux from deep sources, triggered by neotectonic movements in the study area.

Water hydraulic axial piston motor cavitation characteristics based on CFD technology

PurposeThe purpose of this paper is to analyze the cavitation characteristics of a water hydraulic axial piston motor (WHAPM) to improve the water motor performance, to reduce the vibration and noise and to prolong the service life of the motor.Design/methodology/approachThe computational fluid dynamics (CFD) software PumpLinx is chosen to do cavitation analysis of the WHAPM. In this case, first, cavitation mechanism of the water piston motor is analyzed in depth. Then, considering the effects of bubble dynamics, the rate of phase transition, turbulence effects and non-condensable gas, the full cavitation model is selected, the dynamic CFD numerical model of internal flow field on the water hydraulic piston motor is established based on PumpLinx software and the fluid cavitation inside is numerically studied. Finally, the influence of the valve plate and pistons on motor cavitation is analyzed.FindingsResearch results show that there are two serious cavitation regions: one is the pressure transition region of the valve plate that is near the top dead center, and the other is the low-pressure region of the piston that is near the low-pressure transition area. Moreover, the more serious cavitation area is on the valve plate region.Originality/valueThe simulation results show that the proposed algorithm is able to detect the cavitation characteristics of the water piston motor. Besides, it is deduced that valve-plate structure optimization is more important than pistons to reduce cavitation influence.

Vibration Analysis and Experimental Research of the Linear-Motor-Driven Water Piston Pump Used in the Naval Ship

Aiming at the existing problems of traditional water piston pump used in the naval ship, such as low efficiency, high noise, large vibration, and nonintelligent control, a new type of linear-motor-driven water piston pump is developed and its vibration characteristics are analyzed in this research. Based on the 3D model of the structure, the simulation analyses including static stress analysis, modal analysis, and harmonic response analysis are conducted. The simulation results reveal that the mode shape under low frequency stage is mainly associated with the eccentricity swing of the piston rod. The vibration experiment results show that the resonance frequency of linear-motor-driven water piston pump is concentrated upon 500 Hz and 800 Hz in the low frequency range. The dampers can change the resonance frequency of the system to a certain extent. The vibration under triangular motion curve is much better than that of S curve, which is consistent with the simulation conclusion. This research provides an effective method to detect the vibration characteristics and a reference for design and optimization of the linear-motor-driven water piston pump.

Distribution of methane and carbon dioxide concentrations in the near-surface zone and their genetic characterization at the abandoned “Nowa Ruda” coal mine (Lower Silesian Coal Basin, SW Poland)

The closure of hard coal mines in the Lower Silesian Coal Basin (SW Poland) resulted in migration of coal-bed gases (mostly methane and carbon dioxide) towards the surface. The gases were driven out by rising groundwater table in the Pennsylvanian aquifer (so-called “water piston effect”). Because such migration may be a hazard for inhabitants living in the post-mining lands a surface geochemical survey was carried out in the area of the closed “Nowa Ruda” hard coal mine. The research aimed at: (i) evaluating the distribution of methane and carbon dioxide concentrations in the near-surface zone, (ii) determining the genetic characteristics of soil gases and (iii) comparing their characteristics with that of coal-bed gases. The surface geochemical survey included sampling of soil gases and chromatographic analyses of samples for methane and carbon dioxide concentrations and for stable carbon isotope composition in samples of increased methane and carbon dioxide concentrations. Samples were collected along 8 sampling lines located in the mining fields “Piast”, “Słupiec” and “Wacław”. In total, 390 soil gas samples were collected from 1.2m depth. Maximum methane and carbon dioxide concentrations were 7.8 and 5.8vol.%, respectively. Almost all methane encountered in the analyzed samples of soil gases are of microbial origin and were generated during recent anaerobic processes in the near-surface zone. High concentration of carbon dioxide was generated by aerobic biodegradation of organic matter in abandoned mines. Moreover, carbon dioxide was originated during the near-surface oxidation of methane. Only sometimes insignificant thermogenic component of coal-bed methane and carbon dioxide which migrated to near-surface zone from Pennsylvanian coal-bed strata occurs. Moreover an insignificant component of endogenic carbon dioxide also migrated though the faults from deep-seated volcanic chambers and/or even from upper mantle in the “Piast” mining field. The results of our research revealed that the changes of soils gas concentrations in the “Słupiec” field do not indicate “water piston effect”. The highest state of gas emergency by inflow of deep-gases to near-surface zone could take place in the years 2008–2010 therefore much later than the near-surface measurement sessions in 2004. In the “Piast” field a relatively high number of anomalous concentrations of methane and carbon dioxide were measured. Such values results from degassing of groundwaters, the table of which stabilized within the Pennsylvanian aquifer in 2000. Gases migrated towards the surface along the fracture systems and faults, particularly along the Main and the Great faults. A great number of anomalously high carbon dioxide concentrations were measured in the “Wacław” field, which is an effect of groundwater table stabilization within the Pennsylvanian rocks. Carbon dioxide migrates towards the surface along the bedding planes of Pennsylvanian coal-bearing strata and along the linings of remediated “Wacław” and “Wanda” shafts. The highest state of gas emergency by inflow of deep-gases to near-surface zone caused by the uprising of Pennsylvanian water table (“piston effect”) could take place in “Piast” mining field in the years 1998–2000, and in “Wacław” mining field in the years 1978–1980, therefore much earlier than the near-surface measurement sessions in 2004.

A Research Based on the Deep Self-Balanced Hydraulic Pump

The article will give information about the status of sea water pump technology research, carry out the analysis of the water pump slipper, piston and water pump housing and other key parts of hydraulic pumps, and finally make some optimization and innovation. In addition, there will be a mathematical model simulation for four major friction of the hydraulic pump sea water through the MatLab . The simulation results of the design of water hydraulic pump has a certain significance.

Permeability Characteristics and Classification of Coal Seams in Nigeria

In this work, the permeability characteristics of Nigerian coal seams were determined and these properties were used to investigation the applicability of water infusion in the coal seams to solve coal-mining problems. The experimental work was conducted with Triaxial Compression Machine adapted for the permeability test comprising of Hoek cell, a self- developed water piston, pressure gauge and an overhead water tank. The results of the investigation showed that the permeability measurements of the coals were consistent at the different sites and locations of the coalmines. It also revealed that the difference in coal seam permeability was relatively small in Nigeria.

A Novel Fluid Structure Interaction Experiment to Investigate Deformation of Structural Elements Subjected to Impulsive Loading

This paper presents a novel experimental methodology for the study of dynamic deformation of structures under underwater impulsive loading. The experimental setup simulates fluid–structure interactions (FSI) encountered in various applications of interest. To generate impulsive loading similar to blast, a specially designed flyer plate impact experiment was designed and implemented. The design is based on scaling analysis to achieve a laboratory scale apparatus that can capture essential features in the deformation and failure of large scale naval structures. In the FSI setup, a water chamber made of a steel tube is incorporated into a gas gun apparatus. A scaled structure is fixed at one end of the steel tube and a water piston seals the other end. A flyer plate impacts the water piston and produces an exponentially decaying pressure history in lieu of explosive detonation. The pressure induced by the flyer plate propagates and imposes an impulse to the structure (panel specimen), which response elicits bubble formation and water cavitations. Calibration experiments and numerical simulations proved the experimental setup to be functional. A 304 stainless steel monolithic plate was tested and analyzed to assess its dynamic deformation behavior under impulsive loading. The experimental diagnostic included measurements of flyer impact velocity, pressure wave history in the water, and full deformation fields by means of shadow moire and high speed photography.

태양열 물펌프의 실험적 성능분석

The solar powered water pump is very ideal equipment because solar power is more intensive when the water is more needed in summer and it is very helpful in the rural area, in which electrical power is not available. The average solar radiation power is <TEX>$3.488\;kWh/(m^2{\cdot}day)$</TEX> in Korea. In this study, the experimental system of the water pump driven by the radiation energy were designed, assembled, tested and analyzed fur realizing the solar powered water pump. Energy conversion ken radiation energy to mechanical energy by using n-pentane as operating material was done and the water pumping cycles were able to be continued. The quantity of the water pumped per cycle ranged from 2 L to 10 L depending on the level of the valve open area far the vapour supply. The average quantity was about 4,366 cc. The thermal efficiency was about <TEX>$0.018\%$</TEX>. The pressure level of the n-pentane vapour in flash tank was about <TEX>$110\~150\;kPa$</TEX> and that in the water tank was <TEX>$93\~130\;kPa$</TEX>. The pressure in the condenser during cycles was maintained as about 70 kPa. The condensation of the n-pentane vapour in the water tank was increased with the cycles even though the internal and external insulation were done. Air tank performance was better with increasing of the water piston displacement and the water could be pumped with the water piston displacement becoming higher than 6,500 cc.

水蒸気による駆動する水ピストンエンジン(一般セッション 相変化 I)

For usage of relatively low temperature wasted heat, a steam-driven water piston engine was planned and simulated. This engine was driven by expansion, condensation and compression of steam with oscillation of water head in the cylinder. It was shown that continuous steam supply resulted in an unstable behavior of water piston, and that intermittent steam supply improved the stability of the engine.

Design and development of a water piston solar powered steam pump

Most solar pumping systems are based on photovoltaic receivers driving electric pumps. An alternative system is to use a boiling water solar receiver to operate a direct acting steam pump. The advantages lie in the relative simplicity of the pump giving ease of manufacture, maintenance, reliability and low cost. At De Montfort University a simple direct acting steam pump has been developed over many years, so it has been a natural development to link this with a boiling water solar receiver. This paper is primarily concerned with the operation of the pump and overall system employed.

Are atmospheric CO 2 content and pleistocene climate connected by wind speed over a polar mediterranean sea?

Dust and sea-salt records in polar ice cores indicate that the climate has been windier during ice-ages, and therefore the rate of gas exchange between the atmosphere and ocean should be greater in glacial periods. Increased gas exchange between the atmosphere and poleward-advected, sinking cold water due to higher wind speeds could make the solubility pump more efficient, and this would decrease atmospheric CO 2. To illustrate how this might contribute to atmospheric CO 2 change over the last 150 kyr, the marine Na-concentration in the Vostok ice core is used as a logarithmc proxy for relative wind speed, from which gas piston velocities relative to the present are estimated. The effect of the cold water piston velocity on atmospheric CO 2 is then calculated according to an atmosphere-surface ocean box model. As a results, the solubility pump lowers atmospheric CO 2 about 50 ppm during oxygen isotope stages 2–4 and about 40 ppm during stage 5a-d. Unlike various nutrient rearranging mechanisms, the solubility pump produces little fractionation of carbon isotopes between the surface and deep ocean. Combining wind-induced solubility and nutrient-based effects, using Δδ 13C in deep-sea core V19–30 as a proxy of the latter, produces a record of atmospheric CO 2 which is similar to that observed in the Vostok ice core.

The changing patterns of ΔpCO2 between ocean and atmosphere

The average difference between the partial pressure of CO2 in ocean surface water and the overlying atmosphere (ΔpCO2 = pCO2,ocean) ‐ pCO2,atm) has been changing ever since the beginning of the anthropogenic era due to the dumping of CO2 as a waste gas into the atmosphere. However, the change in the difference has not been uniform over the surface of the oceans. This work assesses regional variations in the Earth scale patterns of sources (ΔpCO2&gt;0) and sinks (ΔpCO2&lt;0) during this anthropogenic transient. The regional correction, ΔpCO2*, is defined as the quantity that must be added to a region's preanthropogenic ΔpCO2 to give its present value. Using a five‐box ocean model with special surface regions for the prominent equatorial Pacific source and north Atlantic sink, we show that a larger magnitude of ΔpCO2* is necessary for these two regions than for the average ocean. Analytical results with a multiple one‐and‐one‐half‐box model, in which horizontal water exchanges are neglected, indicate that the ratio Of ΔpCO2* values for any two regions should vary inversely with the ratio of their gas exchange coefficients and nearly directly with the ratio of their deep‐to‐surface water piston velocities. The ΔpCO2* values for regions of the five‐box model vary by as much as a factor of six; predictions of the multiple one‐and‐one‐half‐box model are within a factor of two. Discrepancies from these predictions are believed to be due to horizontal and intermediate‐depth water exchanges, which tend to equalize the ΔpCO2* values. Our best estimate is that regions with large vertical water exchanges (equatorial and high‐latitude zones) and/or low gas exchange coefficients (equatorial zones) have ΔpCO2* magnitudes at least twice as large as the magnitude of ΔpCO2* for the average global ocean.

Combustor and Seal System for a Water Piston Propulsor

The Water Piston Propulsor (WPP) is an advanced in-water propulsion system for Marine Corps amphibious vehicles. Significant weight and volume reductions are the primary advantages of the WPP system versus the more conventional propulsion technologies used today. WPP thrust is produced by porting high-pressure combustion gases into the water-filled channels of a rotor. Gas expansion results in the expulsion of water from the downstream end of the rotor channel. Solar Turbines Incorporated, a subsidiary of Caterpillar Inc., is currently under contract to the David Taylor Research Center for the development of the high-temperature, high-pressure combustor and rotor seal systems. Details of combustor and rotor seal design, performance, and development test are discussed.

Method of generating a seismic signal employing a water piston

A method of generating a seismic signal by forming a shallow hole in the earth's surface, at least partially filling the hole with liquid, positioning a projectile firing apparatus over the hole and firing a projectile downward into the hole impacting the liquid therein.