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Background : Elastomeric infusion pumps are widely used in the delivery of parenteral medications in the home, but real-life conditions may not match calibration or standardised testing conditions. This study investigated the impact of changes in infusion pump height and/or back pressure on infusion pump function. Methods : Volume delivered after one day, infusion duration, average and peak flow rates and time spent within stated accuracy were determined for four elastomeric and one electronic pump using gravimetric technique. Experiments were repeated after altering the height of the pump relative to the output (±40cm, ±20cm) and/or adding a back pressure (10-30mmHg) to the output of an attached catheter. Results : Under ideal operating conditions, the flow rate deviated from that specified by the manufacturer and between 88.5% and 99% of the total infusion volume was delivered. Varying the height or applying back pressure led to further changes in average flow rates and the volume of infusion solution delivered by the elastomeric pumps, but had little effect on the electronic pump. Conclusions : Clinicians should consider potential impact on drug delivery, safety and therapeutic effect for home infusion patients given variations in infusion pump performance observed in this study.

Background: Connecting an infusion line to a closed stopcock results in pressurization of fluid within the syringe infusion pump assembly leading to flow irregularities when opening the stopcock and activating the pump. Aims: It was the purpose of this study to assess the extent of pressurization under different conditions and its impact on start‐up fluid delivery. Methods: Intraluminal pressures and start‐up fluid delivery at 1 mL/h flow rate were assessed with connection of the infusion line 1 min (delayed connection) or immediately after purging (immediate connection) using two different infusion lines made from polyvinylchloride (PVC) or polyethylene (PE). Results: Delayed connection resulted in an increase of intraluminal pressures from zero to 5.1 [4.5 to 5.7] mmHg with the PVC line and from zero to 47.1 [44.8 to 49.3] mmHg with the PE line (mean difference 42.0 [95% CI 39.3–44.7] mmHg; p <.0001). Immediate connection resulted in an increase of intraluminal pressures from zero to 44.3 [41.8–46.8] mmHg with the PVC line and from zero to 61.3 [57.2–65.4] mmHg with the PE line (mean difference 17.0 [95% CI 11.8–22.2] mmHg; p <.0001). The increase in intraluminal pressures was significantly higher with PE lines for both delayed and immediate connection when compared to the PVC lines (mean difference 29.5 [95% CI 19.3–39.7] mmHg; p <.0001). Related fluid volumes delivered at 10 s and 360 s after starting the pump ranged from −252% to 1321% (10 s) of expected infusion volumes and from 59% to 129% (360 s), respectively. Conclusions: Both, timing of infusion line connection after purging and infusion line characteristics considerably affect intraluminal pressures and start‐up fluid delivery when connecting a new syringe infusion pump assembly to a closed stopcock. Consecutive alterations in drug administration can have considerable hemodynamic consequences when dealing with catecholamine infusions in critically ill patients. [ABSTRACT FROM AUTHOR]

Rational and energy efficient operation of pumps for pumping and transporting liquids used in difficult conditions of mining is possible due to the implementation and use of modern methods of managing the operating modes of the pumps. Nowadays, the methods and resources used to regulate the operating modes of pumping units do not meet modern requirements, and many mines still use outdated methods of regulating the operating modes of pumps, which entails significant energy losses and an increase in the cost of the transported liquid. In the article, the methods of reducing electricity losses and the impact on the performance of pumping units were considered. It is concluded that this method of regulating work makes it possible to operate pumping units in the working area. Our article considers and experimentally substantiates the possibility of achieving savings in electrical energy, as well as increasing the reliability of the operation of pumping units based on the use of modern methods of regulating operating modes.

The work is devoted to the study of the parameters of an installation for heating a coolant using liquid forcing through throttle openings. A scheme of a full-size experimental stand has been developed and the principles of operation are described in detail. For visual observation of the state of the liquid at different angular speeds of rotation of the rotor, a transparent drum model is made. The influence of the shape of the rotor skirt and the depth of its immersion in the liquid on the filling capacity of the rotor cavity at an angular velocity from 42 to 314 rad/s has been determined. The optimal parameters of the depth of immersion of the drum skirt with a diameter of 0.5 m in the liquid, at low rotor speeds of 16, 24, 32 rad/s, were obtained. The angle of inclination is calculated and it is experimentally proved that for a conical shape it is 5 degrees. It was found that at angular velocities of the rotor more than 100 rad/s, the shape and depth of immersion of the skirt in the liquid do not affect the filling of the rotor, since the feed is higher than its flow through the throttle openings. It is shown that the use of rotational forces to heat the liquid allows using an electric motor with less power, since it is spent only on unwinding the rotor with the liquid. The calculated dependence of the liquid pressure on the side walls of the rotor, the liquid heating temperature on the angular velocity of rotation of the rotor and on two values of the area of the throttle openings, at 31.4·10–6 m² and 64.34·10–6 m², is obtained. When the total area of the throttle openings is doubled, the temperature of the liquid heating at the same angular velocities increases from 35.6 °C to 82.5 °C. The above installation parameters allow you to get hot water when using small shell-and-tube heat exchangers [ABSTRACT FROM AUTHOR]

The paper introduces a new approach to solving the problem of optimization of dynamic systems «pump+pipe network». In the article the volume of fluid admitted through each pipe in a given time is called the state of pumping. These volumes are taken as basic time-dependent functions describing injection. The system of functions defines an imaginary line – the trajectory of injection in the space, set by the planned volumes of injection through each pipeline. Regulation of flow in the pipelines by any devices, which create local hydrodynamic resistance, allows obtaining different trajectories. The impact of control devices is estimated by the openness coefficient of a pipeline or flow, defined as the ratio of flow in partially blocked pipeline to the flow in the fully open pipeline. The paper considers two options of injection, which demonstrated that different trajectories could meet its own energy consumption. The authors have analyzed the value, equal to the ratio of the pressure produced by the pump to the efficiency corresponding to this pressure, used in quantitative research and assessment of pump operation. It is shown that with increasing pressure or with decreasing feed the given value grows. Since the required pump energy depends on the shape of the trajectory, the energy becomes a functional. To find the minimums of this functional the variational methods are used. This is the way for finding extremal trajectory, where energy and time cost is minimal. A trajectory describing the optimal injection mode is a straight-line segment in an injection space, the ends of which correspond to the initial and final states of injection. To implement this process, the authors proposed the algorithm to determine which pipeline should be partly blocked, and calculate a measure of blocking, considering control device as the device that sets the local resistance coefficient. The main aim of the research was to determine the optimal way of pumping into two pipelines, in which the pump and the pipeline network are considered as a single interconnected system. Objects: pumps used to maintain reservoir pressure, two pipelines equipped with devices for controlling fluid flow. Methods: method for finding the optimal regime – calculus of variations. Results. Pump operation requires the least amount of energy and time, if the filling of the set volumes occurs simultaneously. The paper introduces the algorithm for determining the degree of blocking the pipelines for pumping in two pipelines.

A mathematical model of fluid flow in a two-stage reciprocating hybrid volumetric power machine with a second compression stage profiled from two truncated cones (a diffuser and a confuser) is developed. The model uses the energy conservation equation in the form of the Bernoulli equation, written both with and without compressibility of the fluid. Head losses were determined, including head losses along the length, head losses on local resistance, and inertial head losses. The developed mathematical model can be used to calculate not only a PDRHPM, but also the booster stages of medium-and high-pressure compressors that use a liquid piston. [ABSTRACT FROM AUTHOR]

In order to improve the friction characteristics of the friction pair, find the flow state of particles in the oil film and the temperature distribution of oil film in flow distribution pair, the effects of solid particles in the oil on the oil film characteristics and volumetric efficiency of high-pressure vane pump were studied by means of theoretical analysis, numerical simulation and experimental test in this paper. Firstly, the two-phase flow calculation model was established, and the particle gravity equation and motion resistance equation were established also. Then, the passage model of flow distribution pair was set. The fluid domain of flow distribution pair included the oil port, groove and oil film. The passage model was meshed and the boundary conditions were set. According to the relevant standard of cleanliness requirement of hydraulic fluid system, the solid particle diameter was selected as 0.005, 0.010 and 0.013 mm, and the solid-phase volume fraction was selected as 0.2%, 0.6% and 1% for calculation. Finally, the influnce of solid particle diameter, solid-phase volume fraction and operating parameters on the flow field characteristics of oil film were analysed by FLUENT software. By changing the diameter and solid-phase volume fraction of solid particles, the working pressure and rotating speed of the pump, the nephogram of solid-phase volume fraction distribution and temperature distribution of the oil film in the flow distribution pair were obtained by numerical simulation and verified by test. The result showed the addition of solid particles in the oil had no effect on the pressure value and distribution of the oil film, but it leaded to the decrease of the oil film temperature in the oil discharge area, and the maximum change of oil film temperaturewas 2 K. The solid-phase volume fraction of oil film in the oil suction area decreased with the increase of particle diameter with the maximum change of 0.25%, while it increased in the oil discharge area with the maximum change of 0.35%. On the whole, the solid-phase volume fraction of oil film changed in the increasing trend, and the maximum change was 0.72%. The volumetric efficiency of vane pump decreased with the increase of solid particle diameter, and the relationship between them was approximately linear. With the increase of the solid-phase volume fraction of solid particles, the solid-phase volume fraction of oil film increased, which resulted in the decrease of volumetric efficiency of vane pump. The relationship between solid-phase volume fraction and volumetric efficiency was nonlinear. The surface temperature of oil film decreased with the increase of solid-phase volume fraction. The position of maximum change of oil film temperature was oil discharge area, and the maximum change was 2 K. The solid-phase volume fraction of oil film decreased with the increase of working pressure, and the maximum change was 0.3%. The temperature of all areas on the surface of the oil film was increased, and the temperature change of the core area was 4 K. The solid-phase volume fraction and temperature in most areas of oil film increased with the increase of rotating speed. The maximum change of solid-phase volume fraction and temperature of oil film was 0.2% and 3 K respectively in the areas with great effect. This research provides a reference for the flow distribution pair design of the port pair of high-pressure vane pump when the oil contains solid particles. [ABSTRACT FROM AUTHOR]

The paper presents the results of critical experiments to study the dynamic stability of a power unit with the VVER-1200 reactor conducted as part of the pre-commissioning activities at the pilot operation stage of Novovoronezh NPP II's unit 1. The following dynamic tests were conducted: – trip of one main feedwater pump (MFP) with no standby MFP starting to operate at the power level of 100% Nnom, involving a detailed analysis of the variation in the process parameters of such mode and the process dynamics, and an assessment of the test results on a full-scale simulator; – trip of one out of four reactor coolant pump sets (RCPS) in operation at the power level of 100% Nnom and the reactor plant safety assessment in the context of the reactor core thermal reliability; – turbine generator (TG) load shedding to the auxiliary level with assessments for the behavior of the key reactor plant characteristics. The paper presents records for transients and safety-related process parameters, and describes the operation of the unit components and essential controls in the dynamic test process. A conclusion is made based on an analysis of the test results that the VVER-1200 unit has a high dynamic stability. The results of the dynamic stability studies for unit 1 of Novovoronezh II make it possible to provide a number of recommendations for further designs, including specifically the following: – accelerated warning protection (AWP) should be used instead of power reduction and limiting for modes with tripped main feedwater pumps; – generator-grid timing devices should be used for modes with the unit operating for auxiliary power supply; – Russian-developed software and hardware tools should be fully switched to in implementing both normal operation and safety control systems, since the adjustment of protection and interlocking algorithms used in the AREVA software and hardware package introduced at Novovoronezh II requires the developer's authorization which involves substantial time and financial expenditures.

Su dağıtım şebekeleri, genellikle, şebekede basınç açısından en kritik noktalarda yeterli basınç olacak şekilde işletilir. Ancak günün saatleri içindeki debi salınımlarına uyacak ve enerji tüketimini en aza indirecek bir işletme tipi yerine, işletme kolaylığı için, genellikle, basınçların en düşük basıncın oldukça üstünde olduğu düşük basınç şikayetlerine göre bir işletim uygulanmaktadır. Su dağıtım sistemlerinde, zaman, tüketilen su miktarı ve basınç gibi parametreler dikkate alınarak şebeke işletiminin iyileştirilmesi, hem sistemde su kayıplarının önlenmesi hem de enerji verimliliğinin arttırılmasını sağlar. Yerel yönetimler için önemli bir maliyet kalemi olan içmesuyu dağıtım sistemlerindeki enerji tüketimi şebekenin optimum işletimi ile önemli miktarda azaltılarak enerji tasarrufu sağlanabilmektedir. Bu çalışmada, bir organize sanayi bölgesinin su dağıtım şebekesi örnek şebeke olarak ele alınmıştır. Örnek şebekede, su tüketim farklılıkları esas alınarak üç ayrı işletme bölgesi oluşturulmuştur. Bu bölgelerde minimum ve maksimum su tüketimlerinin debi için ekstrem koşullar olduğu kabul edilerek iki ayrı tüketim değeri ve üç işletme için sekiz farklı hidrolik durum oluşturulmuştur. Bu durumlarda oluşan hidrolik koşullar EPANET yazılımı ile simülasyon yoluyla çözümlenmiştir. İşletmede yapılacak iyileştirmelerle elde edilecek enerji tasarrufunu belirleyebilmek için örnek şebekede iki farklı işletme prosedürü tanımlanmıştır: (i) normal (basit) işletme ve (ii) iyileştirilmiş işletme. Çalışma sonunda, iyileştirilmiş işletmenin toplam enerji tüketimini %16 oranında azalttığı hesaplanmıştır. Birim enerji tüketimi normal işletme için 0.314 kWh/m³ değerinden iyileştirilmiş işletme için 0.261 kWh/m³ değerine düşmüştür. Bu çalışma, su dağıtım şebekeleri işletiminin su tasarrufu ve enerji verimliliği açısından iyileştirilmesine ilişkin planlanma çalışmalarında, hidrolik simülasyon yazılımı EPANET’in etkin bir araç olarak kullanılabileceğini ortaya koymaktadır.

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Ozone dissolution system design is important for meeting transfer efficiency (TE) goals. Large sidestream pump flow (L) and high venturi inlet pressure improves TE but increases operating cost. Ozone TE was examined at a 25 gpm (97-Lpm) pilot-scale sidestream system with (SSw-dg) and without (SSwo-dg) degas separation. Under constant ozone dose conditions, process operating parameters were varied including sidestream gas/liquid (G/L) ratio, venturi-inlet water pressure, venturi-outlet water pressure, feed gas pressure, and ozone gas concentration. Performance results included determination of TE, ozone exposure (CTHDT), and hydraulic detention time (THDT). Several design aspects of sidestream ozone systems were examined to improve mass transfer by using remixing devices, protecting ozone gas piping from corrosion, calculating sidestream ozone residual, and driving force for mass transfer. Moisture contamination of ozone supply lines may cause corrosion and/or decomposition of ozone gas that releases heat and destroys ozone. Ozone gas piping design is critical to prevent trapping water that might enter gas pipe during power outage or when units are offline. During plant operation below design flow, multiple constant speed pumps or variable speed pumps were evaluated to reduce overall operating costs. [ABSTRACT FROM AUTHOR]

Water distribution systems are generally operated so as to provide enough pressure at all nodes that are critical in terms of pressure in the network. But, instead of applying an operational plan that fits the flowrate fluctuations in the hours of a day and thus minimizes the energy consumption, for the operation practicality, a complaints-based operational procedure in which pressures at all nodes are well above the minimum allowable pressure limit is preferred. In water distribution systems, improvement of the operational procedure of the network based on time, the amount of consumed water and pressures at the nodes allows both to reduce water losses in the network, to enhance sustainability and also to provide energy efficiency. In water distribution systems, energy consumption, one of the major expenses for local governments today, can be decreased significantly by optimization of water network operations. In this study, the water network of an organized industrial district was considered as the case water network. There operational zones in the network were identified based on the differences in water consumption patterns. With considering minimum and maximum water consumptions as the extreme conditions for flowrate, eight scenarios were identified for two flowrates (i.e. minimum and maximum) and three operational zones. Hydraulic conditions for these scenarios were then analyzed by hydraulic simulations in EPANET 2. In order to assess energy savings via operational improvements, two different operational procedures were identified for the case water network: (i) base operational procedure and (ii) improved operational procedure. As the result of the study, improved operational procedure reduced energy consumption almost 16% for the case water network. Unit energy consumption lowered from 0.314 kWh/m³ for base operation procedure to 0.261 kWh/m³ for improved operational procedure. This study indicates that EPANET, a hydraulic simulation software, can effectively be applied in the planning of operational improvements of water distribution networks. [ABSTRACT FROM AUTHOR]

This paper explores numerically the benefits of water discharge prediction in the real time control (RTC) of water distribution networks (WDNs). An algorithm aimed at controlling the settings of control valves and variable speed pumps, as a function of pressure head signals from remote nodes in the network, is used. Two variants of the algorithm are considered, based on the measured water discharge in the device at the current time and on the prediction of this variable at the new time, respectively. As a result of the prediction, carried out using a polynomial with coefficients determined through linear regression, the RTC algorithm attempts to correct the expected deviation of the controlled pressure head from the set point, rather than the currently measured deviation. The applications concerned the numerical simulation of RTC in a WDN, in which the nodal demands are reconstructed stochastically through the bottom-up approach. The results prove that RTC benefits from the implementation of the prediction, in terms of the closeness of the controlled variable to the set point and of total variations of the device setting. The benefits are more evident when the water discharge features contained random fluctuations and large hourly variations. [ABSTRACT FROM AUTHOR]

There are different mechanical presses used to deform or press the material through dies to convert into useful product by applying different conditions like temperature, pressure, speed of ram etc. These material deformation techniques not only used to produce finished products but also to increase the strength of the material by introducing severe plastic deformation. Equal channel angular pressing (ECAP) is a technique used to increase the strength of materials by introducing severe plastic deformation through grains refinement. The ECAP die consisting of two channels intersecting at 90 degree was designed and manufactured to perform angular extrusion. The load was calculated through mathematical modelling. A hydraulic press equipped with conventional temperature control furnace, sensor based limit switches, pressure controlled mechanism and with variable speed control was designed, fabricated and manufactured at UET Taxila. The material used for the fabrication purposes is mild steel. The major designing parameters included stroke length, maximum load, pressure, cylinder bore, sealing mechanism and volume flow rate of working fluid. The main parts of the hydraulic press consist of piston and cylinder arrangement, structure or frame, press stand and hydraulic circuit. The press was tested initially for its leakage and then test was performed on Teflon and Nylon materials at 2 tons of pressure. Later on the aerospace grade aluminum alloy 6061 was pressed through ECAP die at a speed of 9mm/sec. [ABSTRACT FROM AUTHOR]

In the paper considered the schematic circuit, operating principle and arrangement of components assemblies and mechanisms unified hydraulic control system and life support for the family prospective hydromechanical transmission MWTP. The parameters and characteristics are shown for the main regulatory systems and hydraulic mechanisms.

An experimental investigation is conducted to develop an electrohydrodynamic (EHD) pump based on microelectromechanical systems (MEMS) technology. In EHD conduction pumping, Coulomb force is the main driving force for fluid motion. The non-equilibrium process of dissociation and recombination of dielectric liquid, HFE-7100, produces hetero-charge layers in vicinity of electrodes. The attraction between the hetero-charge layers and electrode surfaces generate the net motion in the dielectric liquid by applying asymmetric electric fields. In order to generate the asymmetric electric fields, two electrode plates are prepared. On one plate, an electrode pattern is designed as a series of planar micro scale comb fingers. The other electrode plate is a non-patterned plane surface. The working fluid is confined between the two electrodes which face each other. The generated pressure and the liquid flow rate are measured for the different asymmetric electric fields. The validity of the conduction pumping mechanism is confirmed by experiments.

One of an electrohydrodynamics (EHD) phenomenon is the induced flow of a functional fluid in the presence of an electric field. In this paper, we describe a small pump in which the flow is generated by such an EHD phenomenon. In the case of pumps based on cylindrical electrodes, which thus far have been the focus of our research on EHD pumps, the total circumference length of the edge of the holes in the electrode that generates the rotational flow is small, leading to a small overall one-directional flow velocity. To increase this area, we produced two different electrode pumps in which the electrode (cylindrical; 6 mm diameter, 1 mm width) contains multiple holes. We measured the pressure-flow rate characteristics of our pumps and compared their performances. [ABSTRACT FROM AUTHOR]

A technique of calculating the relationships between the discharge pressures in the pumping cavity and the compressor cavity of a hybrid energy-converting piston machine is proposed. Through the use of the results presented here, a relationship is found between the discharge pressure of the pumping cavity and that of the compressor cavity that assures equality between the mass flow rates of the liquid traveling out of the pumping and compressor cavities and, correspondingly, normal operation of a hybrid energy-converting piston machine. [ABSTRACT FROM AUTHOR]

How to estimate the exact value of pressure losses within a district heating (DH) network been in service for decades, which a pump at pumping station should compensate to achieve maximum benefits and the lowest costs relative to the scenario of the started process of transition to 4th generation district heating (4GDH)? Geographic Information System (GIS) software Zulu© was used to model a DH network and evaluate how specific location will affect hot water flow rates. Pressure, roughness and hydraulic resistance profiles were plotted using hydraulic optimisation software ZuluThermo© – GIS Zulu© add-in. While the new arrangement does not reduce pressure losses themselves, the corrected arrangement provides economic advantage due to lower operation costs and more stable hydraulic profiles. That means that end sections of DH network between the transmission line and consumers become more effective. By calculating pressure loss and temperature degradation the method also allows to detect an optimum location to connect a new consumer where the minimum modernisation is needed. Working with data-driven network models makes it possible to obtain a lot of positive effects at the same time including the main - the DH utility sells more heat and becomes more profitable as the losses are lower. • To ensure low-temperature energy supply, its consumption for pumping is assessed. • Steady-state calculation method is used to evaluate pressure and flow distribution. • To verify, portable ultrasonic flow rate meter&traditional pressure sensors are used. • Electricity consumption is decreased by 394.74 kW, the saving effect is up to 6%. • Effect is achieved by lowering losses, clarifying friction factor&relative roughness. [ABSTRACT FROM AUTHOR]

The authors conducted a detailed study of possible options for geometry of blades with pressure and power characteristics of the impeller. [ABSTRACT FROM AUTHOR]

The unsteady flow inside a large centrifugal pump with stay vanes was analyzed in this study. The static performance and pressure fluctuations in the pump were numerically predicted and were compared with experimental data. Considering the relative positions of the impeller to the volute tongue and stay vanes, the static performance which was obtained using a full unsteady calculation was compared with traditional steady calculation results. A comparison of the results with the experimental data showed that the operation condition farther from the design condition resulted in larger differences between the steady simulation and experimental results, with errors beyond reasonable limits, while the performance curves obtained by the unsteady calculations were closer to the experimental data. A comparison of the pressure fluctuations at four monitoring points with the experimental data showed that the amplitudes at HVSI and HVS2 are much larger than at HD1 and HD2. The main frequency for these four monitoring points, which agreed well with the experimental data, was the blade passing frequency. The relative obvious errors in pressure fluctuations for HD1 and HD2 were due to the inlet flow rate variation of the simulation. Thus, unsteady numerical simulations can be used to predict the pressure fluctuations when designing a pump. [ABSTRACT FROM AUTHOR]

Pressure fluctuation, which impacts on operating security, is the common phenomenon in the pump. In order to study pressure fluctuation phenomenon in the pump, TJ04-ZL-02 axial flow pump model is investigated under different operating conditions by experiment and unsteady calculation based on κ -- ω turbulence model. Numerical results show that the basic frequency amplitude of monitoring points in four sections under small operating condition are larger than that under design operating condition and large operating condition. And there are more random frequency components in each monitoring point, which are low frequency components. Experimental results show that compared with different operating conditions the basic frequency amplitude under design operation condition is not smallest. Under small operating condition the basic frequency amplitude is larger than that under large operating condition. Therefore, running under small operating condition will be easy to cause resonance. Based on this study, it's recommended that avoiding small operating condition should contribute to improving operational stability. [ABSTRACT FROM AUTHOR]

Abstract: This article describes the benefit of monitoring the intravasation rate in addition to the conventional measurement of fluid deficit in hysteroscopic surgical procedures. The intravasation rate is the rate, in milliliters per minute, at which fluid enters the systemic circulation, whereas fluid deficit is the amount of irrigation fluid, in milliliters, already absorbed by the patient. To determine the intravasation rate, a manually operated intravasation monitoring pump was constructed, with which one of us (Dr. Atul Kumar) performed 966 hysteroscopic procedures from May 1993 to February 2010. Because the intravasation rate had to be manually calculated by an assistant, it was decided to replace the assistant with a controller to monitor intravasation rate. The surgical experience gathered from the manually operated pump was used to develop algorithms for the controller. The controller-operated intravasation monitoring pump was constructed, with which 41 hysteroscopic procedures were performed from March 2010 to August 2011. In hysteroscopic procedures, this pump simultaneously displays the real-time intravasation rate and the fluid deficit on an LCD screen. [Copyright &y& Elsevier]

Gas injection is one of the methods used in enhanced oil recovery. A pump is usually used for injection of gas into a core in the laboratory. For precision of the experimental results, it is important to keep experimental errors at the minimum value. In this work, an approach for reduction of one of the most important and effective parameters in the generation of experimental errors during gas injection is presented. One of the main goals of this study is to increase the accuracy of gas injection into a core by using a pump at the experimental scale. In gas injection into a core, if the pump is adjusted to a constant rate, under some conditions, gas injection cannot be conducted with a constant rate and therefore deviation from the constant rate occurs. The value of deviation from the constant rate is different with respect to rock and fluid properties and operating conditions. In this investigation, experiments were carried out on a carbonate core with low permeability. Experimental data and effective parameters on the error in using a pump for gas injection with a constant rate were studied. [ABSTRACT FROM AUTHOR]

Numerical and experimental results were presented in this study, concerning a test impeller of a centrifugal pump. From the experimental point of view, the cavitation was visualized at different Inlet Pressure values. Image processing and statistical treatment of the photographs taken at given impeller position allowed to quantify the attached and cloud cavitation extent. A numerical model of 3D cavitating flows, based on the CFD code Fluent 6.1, has been developed to predict the cavitation behavior in our model which is considering the entire pump, the impeller and also the casing of the pump, with all its complex geometry and flow parameters. Non-cavitating and cavitating conditions were investigated. Calculations were found to be in good agreement with experimental measurements and visualisations. Experimental and numerical results concerning the pump parameters were investigated. The overall conclusion is the obvious knowledge that the NPSH is indeed affecting the cavitation condition in the centrifugal pumps, having direct impact on the magnitude of static pressures in various locations inside the pump, but is not altering too much the velocities distributions of fluid. The results obtained show the ability of the model to simulate the main features of 3D cavitating flows in rotating machinery. The rich palette of results shown below is thoroughly investigating the flow parameters of the model. [ABSTRACT FROM AUTHOR]

Abstract: This paper proposed a workless-generator-feeding (WGF) system for a jet refrigeration cycle, using R141b. This feeding system does not require any mechanical power. The liquid refrigerant from the condenser was fed to the vapour-generator by means of the generator pressure and gravitational force. The system was tested and compared with a conventional system using a mechanical pump. It was found that this system was workable. The heat input to the generator was slightly higher than that for a system using a mechanical pump. The jet refrigeration cycle employing this new feeding system provided a slightly lower coefficient of performance (COP) compared to a system using a mechanical pump. However, this new system did not require any mechanical energy. Therefore, the jet refrigeration system employing this WGF system is truly a heat-power refrigeration cycle. [Copyright &y& Elsevier]

Abstract: A novel type of voltage-controlled pump based on electro-osmotic flow has been developed that uses massively parallel micromachined microfluidic channels to generate both high flow rates and high pressures. The approximately half-million microchannels have sub-micron cross-sections, and thus also function as a monolithically integrated microfilter with uniform pore size. This first generation device produces pressures of 5.5kPa/V and flow rate of 0.054mL/min/V/cm2. Such a small and light-weight, yet robust pump makes it useful, and often advantageous in a particularly broad array of applications and systems ranging from drug delivery to cooling microchips to filtration. [Copyright &y& Elsevier]

The helix grooved elastomeric pump (HGEP) is a cylindrical viscous screw pump which will pump high viscosity fluids at high pressures and low flow rates. It incorporates an elastomeric O-ring as part of the pumping mechanism. The theory is developed using the smoothed pressure method. Numerical methods are used to develop data for the HGEP performance. Results are presented for a given pump. The results include the effect of film thickness clearances, groove angles, groove depths, and ridge-to-groove width ratios. The aim of the investigation is to provide a theoretical background for the design of an HGEP. The theory is developed for the smoothed pressure formulation and an elastomeric O-ring model is established. The smoothed pressure formulation and the elastomeric O-ring model is set up for numerical solutions; the data obtained show the effects of various film thickness, clearances, groove angles, groove depths, and ridge-to-groove ratios for a given size pump and pumping fluid. The total volumetric flow rate increases with the reduction of the film thickness clearances. The maximum flow rate is obtained with -.0894 mm film thickness clearances. The computer solution is unstable for clearances less than -.0894 mm. The smaller the ridge-to-groove ratio, the performance is better. [ABSTRACT FROM AUTHOR]

Abstract: The development and testing of two versions of a novel micropump are described: (i) the single-disk viscous pump and (ii) the double-disk viscous pump. The rotational movement of the disk(s) induces viscous stresses on the fluid that forces the fluid from an inlet channel, and then, through the pumping volume above the single disk, or between the two disks. A wiper acts to “wipe” the fluid from the disk(s) toward the outlet channel. The fluid flow through the double-disk pump is visualized using a red Rhodamine dye that is injected into the fluid passage upstream of the pumping volume. These visualizations provide information on the relative importance of viscous forces, centrifugal forces, and static pressure variations. The maximum flow rates and pressure rises are 1.0ml/min, 643Pa, and 2.1ml/min 1.19kPa for the single-disk and double-disk pumps, respectively, for a rotational speed of 5000rpm, a disk diameter of 2.38mm, and a gap height of 103μm, and supplied power to the motor of 7W. The disk pumps are fabricated using precision machining techniques employed on a lathe and milling machine. Advantages of the viscous disk pumps include: simplicity of design, planar structure, continuous flow, well controlled flow rate, and, if desired, the ability to augment mixing in the fluid. [Copyright &y& Elsevier]

Abstract: Micro-ejectors to supply fuel–air mixture to micro-combustors were fabricated and tested. The ejector sucks air using the jet of vaporized liquid gas ejected from a nozzle by its own vapor pressure, and needs no moving part and electric power supply. A tapered nozzle and a Laval nozzle were fabricated by the deep reactive ion etching of silicon. Using the Laval nozzle, which produces supersonic flow, the performance of the ejector becomes high, and the maximum entrainment ratio, which is defined as the volumetric ratio between ejected fuel flow and sucked air flow, reached 36.8. This entrainment ratio is stoichiometrically enough for the complete combustion of butane (>31). At this time, the flow rate of fuel–air mixture was 394sccm. We investigated several characteristics of the prototyped ejectors. The most important problem that we found is that entrainment ratio considerably drops, when several tens Pa pressure is applied at the exit of the ejector by the pressure loss of a combustor. However, the performance of the ejector will be improved by optimizing the design of the Laval nozzle according to the supplied pressure of fuel. [Copyright &y& Elsevier]

Abstract: In order to overcome the shortcomings of the traditional sealing for dry Roots pump, we first designed magnetic fluid sealing and calculated its magnetic field distribution. In addition, since the differential pressure formulas sustained by the seal in most literature are inaccurate or incorrect, we precisely deduced and obtained the differential pressure formula of magnetic fluid sealing before we tested the differential pressure sustained by the seal and the influence of rotation speed on vacuum degree in the test platform. The dry Roots pumps using magnetic fluid sealing have been working well for almost four years up to now, which shows that the performance of the magnetic fluid sealing for dry Roots pump is good. We have successfully developed “the dry Roots pump with magnetic fluid sealing” which was accepted as the state patent and authenticated as the achievement in the scientific research in 2000. [Copyright &y& Elsevier]