Electric Pump System Research Articles

Exploitation of moderate wind resources by autonomous wind electric pumping systems

A laboratory test rig has been developed, in order to analyse the mutual interaction of the different components of a low power WEPS, in the presence of arbitrarily chosen wind intensity. The performances with moderate wind speed of a system composed by a horizontal axis, fixed-pitch wind turbine, a synchronous generator and a centrifugal electric pump have been investigated, both at the start and under steady-state conditions. A control strategy of the alternator field voltage, which facilitates the starting of the pump in the presence of modest wind intensity and maximises average water discharge under any wind condition, has been defined, implemented on an electronic board and tested.

An alternative isolated wind electric pumping system using induction machines

An isolated variable speed variable frequency wind electric pumping system is proposed. Induction machines are used both in the generation unit as well as in the pumping unit and a static VAr compensator is used for providing the magnetizing currents of both machines. An indirect induction generator stator flux control strategy is adopted. System steady state and dynamic operation is studied based on simulation and experimental results.

96/00640 Photovoltaic, wind and diesel. A cost comparative study of water pumping options in Jordan

In the present study, the economics of water pumping by different methods are discussed. The methods investigated are the diesel generation system (DGS), the photovoltaic generation system (PVGS), the mechanical wind pumping system (MWPS) and the electrical wind pumping system (EWPS). The results from the sites studied revealed lower costs for both the photovoltaic and mechanical wind pumping systems than diesel generation, while higher costs were noted for the electrical wind pumping system. The results of this study also showed that at low capacities it is more economical to use PVGS than other methods

Photovoltaic, wind and diesel: A cost comparative study of water pumping options in Jordan

In the present study, the economics of water pumping by different methods are discussed. The methods investigated are the diesel generation system (DGS), the photovoltaic generation system (PVGS), the mechanical wind pumping system (MWPS) and the electrical wind pumping system (EWPS). The results from the sites studied revealed lower costs for both the photovoltaic and mechanical wind pumping systems than diesel generation, while higher costs were noted for the electrical wind pumping system. The results of this study also showed that at low capacities it is more economical to use PVGS than other methods

The Applicability of Electrically Driven Accessories for Turboshaft Engines

Improved electrical power generation and actuation systems offer new design approaches for performing the engine control and accessory functions in helicopter propulsion systems. Present helicopter technology utilizes turboshaft engines with mechanically driven accessories. These accessories perform the functions of starting, fuel and lube pumping, variable stator actuation, and inlet particle separation. This paper discusses the applicability of replacing the mechanically driven accessories with their electrically driven counterparts. An electric accessory system is defined, which includes a switched reluctance starter/generator and its associated control unit; an electric pumping and actuation system; and the engine mounting for the starter/generator. A comparison between the mechanically and electrically driven accessory systems is performed on the basis of cost, weight, and reliability. Experience to date with switched reluctance machines and electrically driven turbo shaft accessory systems is summarized. The benefits of electrically driven accessories are shown and recommendations for future activity for his important technology are discussed.

Development of small centrifugal pumps for an electric propellant pump system

Small centrifugal pumps with low specific speeds have been designed, manufactured and performance tested at Volvo Flygmotor AB under a contract from the European Space Agency (ESA) over the period mid-1985 to mid-1988. The development of the pumps is a part of the work carried out to develop an Electric Propellant Pump System (EPPS) for the storable propellant monomethyl hydrazine (MMH) and nitrogen tetraoxide (NTO). Supporting technology development has been funded by the Swedish Delegation for Space Activities (DFR) and Swedish Space Corporation (SSC) together with Volvo Flygmotor. The main advantages of a typical EPPS communication satellite application are weight and volume reduction of the propellant system compared with a pressure-fed system. Active engine mixture ratio control and improved propellant utilization are also possible. Refuelling in space is another potential application where EPPS can be used. The development work was focused on communication satellite apogee propulsion and used the MBB 3 kN engine as reference. This paper presents the pump design and analyses and the results from the test campaigns of three different pump configurations, carried out with water as test liquid. The head rise, efficiency and suction performance together with other characteristics are also given. The planned next development step is to demonstrate pump performance in the propellants and primarily in NTO. The step is funded by (DFR)/(SSC) together with Volvo Flygmotor.

Toward an implantable artificial heart. Experimental and clinical experience at The Pennsylvania State University.

The number of patients who would be candidates for replacement of their failing native heart with an artificial device increases every year. A multidisciplinary group at The Pennsylvania State University is working toward the development of a reliable, totally implantable artificial heart. Initial work resulted in a pneumatic total artificial heart that has performed well in animal implants and has been used clinically in three patients as a temporary bridge to cardiac transplantation. Although pneumatic total artificial hearts have demonstrated utility as temporary mechanical circulatory support devices, attempts at permanent implantation by other groups have been fraught with complications. Because of the suboptimal performance of the pneumatic devices used for permanent implantation, the authors' groups at Penn State is developing n electric motor-driven total artificial heart with encouraging results in calf implants. This artificial heart of the future will use a transcutaneous energy transmission system that will obviate the need for percutaneous lines. Thus, the patient will be provided with as near a normal life-style as possible. At present the technology is at hand to implant an electric blood pump system that should provide a reasonable life-style and function reliably with minimal care. Ongoing cooperative experimental efforts will help to provide the answers necessary to make this system ready for clinical use.

Determination of transuranic and thorium isotopes in ocean water: In solution and in filterable particles

A sensitive technique for the measurement of dissolved and particulate actinide concentrations and water column distributions is described. Pu, Am, and Th isotopes are collected using large-volume, wire-mounted electrical pumping systems. Particles were removed by filtration, and actinides by absorption on MnO2-coated filters. The very large volumes processed (up to 4000 liters) result in very sensitive and precise concentration measurements after analyses of the samples by standard radiochemical and alpha spectrometric techniques.

Lightning Protection for Submergible Oilwell Pumps

Lightning protection for electric submergible pumps has long been an area of concern. Related insulation failures are costly and not altogether uncommon. These are due in part to poor-quality grounds and the tightly spaced geometry of submergible motor windings. An improved protection scheme is proposed wherein separate high-and low-current grounds are used, and the rate of voltage rise is limited. These techniques divert the major portion of lightning energy before it reaches the downhole equipment, thus minimizing coil-to-frame voltage stress. It also slows the rate of voltage rise to reduce turn-to-turn stress within a single motor coil. Design considerations are developed for the protection of an electric submergible pumping system, particularly as they relate to the value, quality, and reliability of individual protection components and various grounding systems. Laboratory test data are presented, showing the effects of motor impedance on performance when characteristic lightning transients are applied. Finally, available field data are reviewed.

Analysis of the reliability of submersible centrifugal electric pumping systems

A modern submersible centrifugal electric pumping system (SCEPS) for oil production consists of a submersible part which includes a centrifugal pump, an electric motor, a hydroprotection arrangement, a cable line, and an aboveground part that includes a control station and a transformer. The author discusses the mean service life of the submersible part of the SCEPS as the most important parameter of reliability of the SCEPS. The effect of the operating factors is assessed by calculating the mean service life of the submersible part of the typical SCEPS, making allowance for failures resulting from all causes. The mean operating time until failure of the submersible part of the new SCEPS due to design and technological error was determined.

Subsurface Electrical Centrifugal Pumps

Summary The first subsurface electrical centrifugal pump for oilwell service in the U.S. was installed in the Russell field, KS, in 1926. Since that time many improvements have increased the efficiency of the pump at various pumping rates and depths in a variety of casing sizes. Each oil well has a different producing environment that the design engineer must consider to optimize the pumping installation for maximum service life. This paper discusses the major items involved in selection of a subsurface electrical centrifugal pump for a specific application. Additionally, installation, operating, and servicing practices are discussed. Introduction The basic arrangement of downhole equipment of the subsurface electrical pumping system has not changed from that used in the first installation at Russell field. However, engineering improvements have been made to the pump, motor, seal, cable, and surface control systems to handle greater depths, corrosive fluids, higher temperatures, and low gas-liquid ratios (GLR's) to increase the efficiency and economic life of the pumping system. Installation and operating techniques have also changed. Engineers must understand the design limits of each component to make the optimal selection of the equipment. The operator must understand these limits to obtain maximum system life without a premature failure. Although there are other equipment installation arrangements, such as cable-suspended pumps, inverted pumps, and shrouded motors, this paper discusses only the standard equipment arrangement shown in Fig. 1 where the base of the pump motor is located approximately 30 m [98 ft] above the top of the producing formation. Discussion Pump The multistage centrifugal pump is located at the bottom of the tubing string (Fig. 1) with the pump intake located at the base of the pump. The pump consists of the multistage centrifugal impellers on a single shaft inside a single tubular housing of diffusers approximately 9 m [30 ft] long. Tandem pump systems may join two or more single-shaft pumps in series through the use of splined couplings between the shafts and a flange bolting for each housing. The total length of a tandem pump can be as long as 21.95 m [72 ft]. A single-stage centrifugal pump consists of one impeller and one diffuser. Fig. 2 shows a typical pump stage with the general nomenclature for the impeller and diffuser. Most impellers used in subsurface electrical pump designs have a nondimensional, specific speed number in the range of 1,500 to 6,000. The U.S. Hydraulic Inst. defines specific speed, Ns, of a centrifugal pump as the speed in revolutions per minute (rev/min) at which a geometrically similar impeller would operate if it were of such a size as to deliver 0.23 m3/hr [1 gal/min] against 0.3m [1 ft] of head. Head is defined as the lift that one stage at a given rev/min and capacity will generate (in meters [ft]). The following formula shows the relationship of a nondimensional design index. (1) where N = pump speed, rev/min, Q = capacity at the peak efficiency point, m3/min [cu ft/min], andH = total head per stage at the peak efficiency, m [ft]. Radial flow impellers with lower specific speeds develop head principally through centrifugal force. The higher-specific-speed pumps develop head through centrifugal and axial forces. The impeller illustrated in Fig. 2 is an example of a mixed-flow impeller (centrifugal and axial) with a specific speed of approximately 4,000. The capacity of a single stage is determined by the average OD of the impeller, the rev/min that the impeller turns, the space between the upper and lower shrouds, the average diameter of the eye space, and the curvature of the impeller vanes. Therefore, the greater the speed, OD, and shroud spacing, the greater the capacity. The eye diameter and curvature of the vanes affect the efficiency of the system. An additional impeller adds to the head but does not change the capacity of the first impeller. Each impeller develops a head that mathematically can be converted into pressure by multiplying the head generated on test by 100 times the specific gravity of the fluid being pumped (pure water is 1.000 at 20 deg. C [68 deg. F] at standard 10 MPA [1.0 bar] atmospheric pressure). Therefore, the discharge pressure of the impeller will act on the surface of the impeller exposed to it. Fig. 3 shows a cross section of an impeller and the top and bottom views of the impeller thrust areas. JPT P. 645^