Output characteristics of a series three-port axial piston pump

Science.gov (United States)

Zhang, Xiaogang; Quan, Long; Yang, Yang; Wang, Chengbin; Yao, Liwei

2012-05-01

Driving a hydraulic cylinder directly by a closed-loop hydraulic pump is currently a key research area in the field of electro-hydraulic control technology, and it is the most direct means to improve the energy efficiency of an electro-hydraulic control system. So far, this technology has been well applied to the pump-controlled symmetric hydraulic cylinder. However, for the differential cylinder that is widely used in hydraulic technology, satisfactory results have not yet been achieved, due to the asymmetric flow constraint. Therefore, based on the principle of the asymmetric valve controlled asymmetric cylinder in valve controlled cylinder technology, an innovative idea for an asymmetric pump controlled asymmetric cylinder is put forward to address this problem. The scheme proposes to transform the oil suction window of the existing axial piston pump into two series windows. When in use, one window is connected to the rod chamber of the hydraulic cylinder and the other is linked with a low-pressure oil tank. This allows the differential cylinders to be directly controlled by changing the displacement or rotation speed of the pumps. Compared with the loop principle of offsetting the area difference of the differential cylinder through hydraulic valve using existing technology, this method may simplify the circuits and increase the energy efficiency of the system. With the software SimulationX, a hydraulic pump simulation model is set up, which examines the movement characteristics of an individual piston and the compressibility of oil, as well as the flow distribution area as it changes with the rotation angle. The pump structure parameters, especially the size of the unloading groove of the valve plate, are determined through digital simulation. All of the components of the series arranged three distribution-window axial piston pump are designed, based on the simulation analysis of the flow pulse characteristics of the pump, and then the prototype pump is made

Piston pump and method of reducing vapor lock

Science.gov (United States)

Phillips, Benjamin A.; Harvey, Michael N.

2000-02-15

A pump includes a housing defining a cavity, at least one bore, a bore inlet, and a bore outlet. The bore extends from the cavity to the outlet and the inlet communicates with the bore at a position between the cavity and the outlet. A crankshaft is mounted in supports and has an eccentric portion disposed in the cavity. The eccentric portion is coupled to a piston so that rotation of the crankshaft reciprocates the piston in the bore between a discharge position an intake position. The bore may be offset from an axis of rotation to reduce bending of the piston during crankshaft rotation. During assembly of the pump, separate parts of the housing can be connected together to facilitate installation of internal pumping components. Also disclosed is a method of reducing vapor lock by mixing vapor and liquid portions of a substance and introducing the mixture into a piston bore.

Radial-piston pump for drive of test machines

Science.gov (United States)

Nizhegorodov, A. I.; Gavrilin, A. N.; Moyzes, B. B.; Cherkasov, A. I.; Zharkevich, O. M.; Zhetessova, G. S.; Savelyeva, N. A.

2018-01-01

The article reviews the development of radial-piston pump with phase control and alternating-flow mode for seismic-testing platforms and other test machines. The prospects for use of the developed device are proved. It is noted that the method of frequency modulation with the detection of the natural frequencies is easily realized by using the radial-piston pump. The prospects of further research are given proof.

Layered clustering multi-fault diagnosis for hydraulic piston pump

Science.gov (United States)

Du, Jun; Wang, Shaoping; Zhang, Haiyan

2013-04-01

Efficient diagnosis is very important for improving reliability and performance of aircraft hydraulic piston pump, and it is one of the key technologies in prognostic and health management system. In practice, due to harsh working environment and heavy working loads, multiple faults of an aircraft hydraulic pump may occur simultaneously after long time operations. However, most existing diagnosis methods can only distinguish pump faults that occur individually. Therefore, new method needs to be developed to realize effective diagnosis of simultaneous multiple faults on aircraft hydraulic pump. In this paper, a new method based on the layered clustering algorithm is proposed to diagnose multiple faults of an aircraft hydraulic pump that occur simultaneously. The intensive failure mechanism analyses of the five main types of faults are carried out, and based on these analyses the optimal combination and layout of diagnostic sensors is attained. The three layered diagnosis reasoning engine is designed according to the faults' risk priority number and the characteristics of different fault feature extraction methods. The most serious failures are first distinguished with the individual signal processing. To the desultory faults, i.e., swash plate eccentricity and incremental clearance increases between piston and slipper, the clustering diagnosis algorithm based on the statistical average relative power difference (ARPD) is proposed. By effectively enhancing the fault features of these two faults, the ARPDs calculated from vibration signals are employed to complete the hypothesis testing. The ARPDs of the different faults follow different probability distributions. Compared with the classical fast Fourier transform-based spectrum diagnosis method, the experimental results demonstrate that the proposed algorithm can diagnose the multiple faults, which occur synchronously, with higher precision and reliability.

NEW SOLUTIONS FOR THE CONSTRUCTION OF DRILLING PISTON PUMPS VALVES

Directory of Open Access Journals (Sweden)

Рима Явдатовна Абдюкова

2016-08-01

Full Text Available The article consideres theoretical and practical researches aimed to develop a new design of the valve pairs of drill piston pump. The result of the research is a new design of the drill piston pump valve according to the specified requirements.

Analysis of the flow dynamics characteristics of an axial piston pump based on the computational fluid dynamics method

Directory of Open Access Journals (Sweden)

Bin Zhang

2017-01-01

Full Text Available To improve its working performance, the flow ripple characteristics of an axial piston pump were investigated with software which uses computational fluid dynamics (CFD technology. The simulation accuracy was significantly optimized through the use of the improved compressible fluid model. Flow conditions of the pump were tested using a pump flow ripple test rig, and the simulation results of the CFD model showed good agreement with the experimental data. Additionally, the composition of the flow ripple was analyzed using the improved CFD model, and the results showed that the compression ripple makes up 88% of the flow ripple. The flow dynamics of the piston pump is mainly caused by the pressure difference between the intake and discharge ports of the valve plates and the fluid oil compressibility.

Free-piston engine-and-hydraulic pump for railway vehicles

Directory of Open Access Journals (Sweden)

A. F. Golovchuk

2013-04-01

Full Text Available Purpose. The development of the free-piston diesel engine-and-hydraulic pump for the continuously variable hydrostatical transmission of mobile power vehicles. Methodology. For a long time engine builders have been interesting in the problem of developing free piston engines, which have much bigger coefficient of efficiency (40…80%. Such engines don’t have the conversion of reciprocating motion for inner combustion engine piston into rotating motion of crankshaft, from which the engine torque is transferred to the power machine transmission. Free-piston engines of inner combustion don’t have the crank mechanism (CM that significantly reduces mechanical losses for friction. Such engines can be used as compressors. Free-piston engine compressor (FPEC – is a free-piston machine in which energy received from engine’s cylinder is being transferred direct to compressor’s pistons connected with operational pistons of engine without crank mechanism. Part of the pressed air is being consumed for engine cylinder drain and the other part is going to the consumer. Findings. The use of free-piston engines-and-hydraulic pumps as power-transmission plants of power vehicles (diesel locomotives, combine harvester, tractors, cars and other mobile and stationary power installations with the continuously variable transmissions allows cost effectiveness improvement and metal consumption reduction of these vehicles, since the cost effectiveness of FPE is higher by 25-30%, and the metal consumption is lower by 40-50%. Originality. One of the important advantages of the free-piston engines is their simplicity and engine balance. As a result of the crank mechanism absence their construction is much simplified and the vibrations, peculiar to the ordinary engines are eliminated. In such installation the engine pistons are directly connected through the rod to compressor pistons and therefore there are no losses in the bearing bushes. Practical value. The free-piston

The research on flow pulsation characteristics of axial piston pump

Science.gov (United States)

Wang, Bingchao; Wang, Yulin

2017-01-01

The flow pulsation is an important factor influencing the axial piston pump performance. In this paper we implement modeling and simulation of the axial piston pump with AMESim software to explore the flow pulsation characteristics under various factors . Theory analysis shows the loading pressure, angular speed, piston numbers and the accumulator impose evident influence on the flow pulsation characteristics. This simulation and analysis can be used for reducing the flow pulsation rate via properly setting the related factors.

Reciprocating piston pump system with screw drive

Science.gov (United States)

Perkins, Gerald S. (Inventor); Moore, Nicholas R. (Inventor)

1981-01-01

A pump system of the reciprocating piston type is described, which facilitates direct motor drive and cylinder sealing. A threaded middle potion of the piston is engaged by a nut connected to rotate with the rotor of an electric motor, in a manner that minimizes loading on the rotor by the use of a coupling that transmits torque to the nut but permits it to shift axially and radially with respect to the rotor. The nut has a threaded hydrostatic bearing for engaging the threaded piston portion, with an oil-carrying groove in the nut being interrupted. A fluid emitting seal located at the entrance to each cylinder, can serve to center the piston within the cylinder, wash the piston, and to aid in sealing. The piston can have a long stroke to diameter ratio to minimize reciprocations and wear on valves at high pressures. The voltage applied to the motor can be reversed prior to the piston reaching the end of its stroke, to permit pressure on the piston to aid in reversing the motor.

Method and means for repairing injection fuel pump pistons

Energy Technology Data Exchange (ETDEWEB)

Ash, E.G.; Tompkins, M.J. Jr.

1988-06-07

This patent describes an improvement in timing pistons for rotary fuel injection pumps of the type having a die cast aluminum housing. The housing has a cylindrical chamber, a steel piston, the piston being received in the chamber, means for reciprocating the piston lengthwise of the chamber, an aluminum jacket surrounding the piston and extending the full length thereof, the jacket being rigidly secured to the piston. The jacket has an exterior surface hard coat anodized to the hardness of about 60-70 Rockwell (C scale) as the means of preventing galling due to the reciprocal movement of the aluminum jacket piston within the aluminum chamber.

Transient Characteristics of Free Piston Vuilleurnier Cycle Heat Pumps

Science.gov (United States)

Matsue, Junji; Fujimoto, Norioki; Shirai, Hiroyuki

A dynamic analysis of a free piston Vuilleumier cycle heat pump was performed using a time-stepping integration method to investigate transient characteristics under power controlling. The nonlinear relationship between displacement and force for pistons was taken into account for the motion of reciprocating components. The force for pistons is mainly caused by the pressure change of working gas varying with piston displacements; moreover nonlinear viscous dissipative force due to the oscillating flow of working gas in heat exchangers and discontinuous damping force caused by solid friction at piston seals and rod seals are included. The displacements of pistons and pressure changes in the Vuilleumier cycle heat pump were integrated by an ideal isothermal thermodynamic relationship. It was assumed that the flow friction was proportional to the kinematic pressure of working gas, and that the solid friction at the seals was due to the functions of the working gas pressure and the tension of seal springs. In order to investigate the transient characteristics of a proposed free piston Vuilleumier cycle heat pump machine when hot-side working gas temperatures and alternate force were changed, some calculations were performed and discussed. These calculation results make clear transient characteristics at starting and power controlling. It was further found that only a small amount of starter power is required in particular conditions. During controlling, the machine becomes unstable when there is ar elatively large reduction in cooling or heating power. Therefore, an auxiliary device is additionally needed to obtain stable operation, such as al inear motor.

Wear Performance of Bionic Dimpled-Shape Pistons of Mud Pump

Directory of Open Access Journals (Sweden)

Xuejing Cheng

2017-01-01

Full Text Available The piston is one of the parts that most easily become worn out and experience failure in mud pumps for well drilling. By imitating the body surface morphology of the dung beetle, this paper proposed a new type (BW-160 of mud pump piston that had a dimpled shape in the regular layout on the piston leather cup surface and carried out a performance test on the self-built test rig. Firstly, the influence of different dimple diameters on the service life of the piston was analyzed. Secondly, the analysis of the influence of the dimple central included angle on the service life of the piston under the same dimple area density was obtained. Thirdly, the wear of the new type of piston under the same wear time was analyzed. The experimental results indicated that the service life of the piston with dimples on the surface was longer than that of L-Standard pistons, and the maximum increase in the value of service life was 92.06%. Finally, the Workbench module of the software ANSYS was used to discuss the wear-resisting mechanism of the new type of piston.

SLIPPER PERFORMANCE INVESTIGATION IN AXIAL PISTON PUMPS AND MOTORS-FLOW AND VISCOUS POWER LOSSES

Directory of Open Access Journals (Sweden)

A. Osman KURBAN

1997-01-01

Full Text Available In this study, the slippers being the most effective on the performance of swash plate type axial piston pumps and motors, which is a good example of hydrodynamic-hydrostatic bearing applications, have been investigated. With respect to this, having derived the viscous moment loss, viscous flow leakage loss and power loss equations, the variations of these parameters under different operating conditions have been examined experimentally.

Pump having pistons and valves made of electroactive actuators

Science.gov (United States)

Bar-Cohen, Yoseph (Inventor)

1997-01-01

The present invention provides a pump for inducing a displacement of a fluid from a first medium to a second medium, including a conduit coupled to the first and second media, a transducing material piston defining a pump chamber in the conduit and being transversely displaceable for increasing a volume of the chamber to extract the fluid from the first medium to the chamber and for decreasing the chamber volume to force the fluid from the chamber to the second medium, a first transducing material valve mounted in the conduit between the piston and the first medium and being transversely displaceable from a closed position to an open position to admit the fluid to the chamber, and control means for changing a first field applied to the piston to displace the piston for changing the chamber volume and for changing a second field applied to the first valve to change the position of the first valve.

Electromagnetic liquid pistons for capillarity-based pumping

Science.gov (United States)

Malouin, Bernard; Olles, Joseph; Cheng, Lili; Hirsa, Amir; Vogel, Michael

2011-11-01

Two adjoining ferrofluid droplets can behave as an electronically-controlled oscillator or switch by an appropriate balance of magnetic, capillary, and inertial forces. Their motion can be exploited to displace a surrounding liquid, forming electromagnetic liquid pistons. Such ferrofluid pistons can pump a precise volume of liquid via finely tunable amplitudes or resonant frequencies with no solid moving parts. Here we demonstrate the use of these liquid pistons in capillarity-dominated systems for variable focal distance liquid lenses with nearly perfect spherical interfaces. These liquid/liquid lenses feature many promising qualities not previously realized together in a liquid lens, including large apertures, immunity to evaporation, invariance to orientation relative to gravity, and low driving voltages. The dynamics of these liquid pistons is examined, with experimental measurements showing good agreement with a spherical cap model. A centimeter-scale lens was shown to respond in excess of 30 Hz, with resonant frequencies over 1 kHz predicted for scaled down systems.

Design and theoretical analysis of a sliding valve distribution radial piston pump

Energy Technology Data Exchange (ETDEWEB)

Tong, Guo; Shengdun, Zhao; Yanghuiwen, Yu [Xian Jiaotong University, Xian (China); Peng, Shang [Xian Engineering University of Armed Police Force, Xian (China)

2016-01-15

A Sliding valve distribution radial piston pump (SVDRPP) is presented. In this pump, a new distribution method that uses sliding valves to distribute oil for the piston chambers is developed. With this design, the disadvantages brought by the distribution shaft and the check valves (traditional distribution mechanisms), such as the poor stress state of the shaft and the energy waste for opening the check valves, are expected to be eliminated. In addition, a method of using pressure oil to accomplish the returning stroke of the piston is also proposed, which could be used to replace the usage of springs along with their shortcomings. A pump with five pistons is designed as an example to elaborate the structure and the working principle of SVDRPP. Furthermore, the flow characteristics of SVDRPP are studied, and the formulas of the displacement, the average flow rate and the instantaneous flow rate are deduced.

Design and theoretical analysis of a sliding valve distribution radial piston pump

International Nuclear Information System (INIS)

Tong, Guo; Shengdun, Zhao; Yanghuiwen, Yu; Peng, Shang

2016-01-01

A Sliding valve distribution radial piston pump (SVDRPP) is presented. In this pump, a new distribution method that uses sliding valves to distribute oil for the piston chambers is developed. With this design, the disadvantages brought by the distribution shaft and the check valves (traditional distribution mechanisms), such as the poor stress state of the shaft and the energy waste for opening the check valves, are expected to be eliminated. In addition, a method of using pressure oil to accomplish the returning stroke of the piston is also proposed, which could be used to replace the usage of springs along with their shortcomings. A pump with five pistons is designed as an example to elaborate the structure and the working principle of SVDRPP. Furthermore, the flow characteristics of SVDRPP are studied, and the formulas of the displacement, the average flow rate and the instantaneous flow rate are deduced

A magnetically driven piston pump for ultra-clean applications

Science.gov (United States)

LePort, F.; Neilson, R.; Barbeau, P. S.; Barry, K.; Bartoszek, L.; Counts, I.; Davis, J.; deVoe, R.; Dolinski, M. J.; Gratta, G.; Green, M.; Díez, M. Montero; Müller, A. R.; O'Sullivan, K.; Rivas, A.; Twelker, K.; Aharmim, B.; Auger, M.; Belov, V.; Benitez-Medina, C.; Breidenbach, M.; Burenkov, A.; Cleveland, B.; Conley, R.; Cook, J.; Cook, S.; Craddock, W.; Daniels, T.; Dixit, M.; Dobi, A.; Donato, K.; Fairbank, W.; Farine, J.; Fierlinger, P.; Franco, D.; Giroux, G.; Gornea, R.; Graham, K.; Green, C.; Hägemann, C.; Hall, C.; Hall, K.; Hallman, D.; Hargrove, C.; Herrin, S.; Hughes, M.; Hodgson, J.; Juget, F.; Kaufman, L. J.; Karelin, A.; Ku, J.; Kuchenkov, A.; Kumar, K.; Leonard, D. S.; Lutter, G.; Mackay, D.; MacLellan, R.; Marino, M.; Mong, B.; Morgan, P.; Odian, A.; Piepke, A.; Pocar, A.; Prescott, C. Y.; Pushkin, K.; Rollin, E.; Rowson, P. C.; Schmoll, B.; Sinclair, D.; Skarpaas, K.; Slutsky, S.; Stekhanov, V.; Strickland, V.; Swift, M.; Vuilleumier, J.-L.; Vuilleumier, J.-M.; Wichoski, U.; Wodin, J.; Yang, L.; Yen, Y.-R.

2011-10-01

A magnetically driven piston pump for xenon gas recirculation is presented. The pump is designed to satisfy extreme purity and containment requirements, as is appropriate for the recirculation of isotopically enriched xenon through the purification system and large liquid xenon time projection chamber of EXO-200. The pump, using sprung polymer gaskets, is capable of pumping more than 16 standard liters per minute of xenon gas with 750 Torr differential pressure.

Fluid structure interaction in piston diaphragm pumps

NARCIS (Netherlands)

van Rijswick, R.J.A.

2017-01-01

Piston diaphragm pumps are used world-wide to transport abrasive and/or aggressive slurries against high discharge pressures in the mining, mineral processing and power industries. Limitation of excessive deformation of the diaphragm is of utmost importance for eliminating fatigue failures of the

Lead-free, bronze-based surface layers for wear resistance in axial piston hydraulic pumps

Energy Technology Data Exchange (ETDEWEB)

Vetterick, Gregory Alan [Iowa State Univ., Ames, IA (United States)

2010-01-01

Concerns regarding the safety of lead have provided sufficient motivation to develop substitute materials for the surface layer on a thrust bearing type component known as a valve plate in axial piston hydraulic pumps that consists of 10% tin, 10% lead, and remainder cooper (in wt. %). A recently developed replacement material, a Cu-10Sn-3Bi (wt.%) P/M bronze, was found to be unsuitable as valve plate surface layer, requiring the development of a new alloy. A comparison of the Cu-1-Sn-10Pb and Cu-10Sn-3Bi powder metal valve plates showed that the differences in wear behavior between the two alloys arose due to the soft phase bismuth in the alloy that is known to cause both solid and liquid metal embrittlement of copper alloys.

Measurements on a PV solar pump equipped with a piston pump with a matching valve

NARCIS (Netherlands)

Smulders, P.T.; Ten Thije O.G. Boonkkamp, J.; Borg, van der N.J.C.M.; Beek, van M.

1997-01-01

The work on a simple high efficient solar pump equipped with a piston pump with a matching valve, reported at the Solar World Congress in Budapest, has been continued. Quasi-static and dynamic models of the solar pump have been derived with which the operation of the system is simulated. A test rig

Piston-assisted proton pumping in Complex I of mitochondria membranes

Science.gov (United States)

Mourokh, Lev; Filonenko, Ilan

2014-03-01

Proton-pumping mechanism of Complex I remains mysterious because its electron and proton paths are well separated and the direct Coulomb interaction seems to be negligible. The structure of this enzyme was resolved very recently and its functionality was connected the shift of the helix HL. We model the helix as a piston oscillating between the protons and electrons. We assume that positive charges are accumulated near the edges of the helix. In the oxidized state, the piston is attracted to electrons, so its distance to the proton sites increases, the energy of these sites decreases and the sites can be populated. When electrons proceed to the drain, elastic forces return the piston to the original position and the energies of populated proton sites increase, so the protons can be transferred to the positive site of the membrane. In this work, we explore a simplified model when the interaction of the piston with electrons is replaced by a periodic force. We derive quantum Heisenberg equations for the proton operators and solve them jointly with the Langevin equation for the piston position. We show that the proton pumping is possible in such structure with parameters closely resembling the real system. We also address the feasibility of using such mechanism in nanoelectronics.

A liquid helium piston pump with a superconducting drive

International Nuclear Information System (INIS)

Schmidt, C.

1984-01-01

This chapter describes a bellows pump where the driving force is achieved by an arrangement of three superconducting coils. The pump was designed for use in the supercritical helium flow circuit of the LCT-conductor test facility. The main advantage of the superconducting drive, compared to conventional pumps with external drive, is the compact design. Force transferring parts between 4.2 K and room temperature are not necessary. The pump was tested in a closed loop arrangement. The superconducting drive for a piston pump consists of a moving coil in a constant background field. Other coil configurations and the upscaling of the pump design are discussed

Present situation and the future task of pumps and motors for mobile application; Kensetsu kikai sharyoyo pump/motor no genjo to kadai

Energy Technology Data Exchange (ETDEWEB)

Ishii, S.

1994-09-15

The current technologies of hydraulic pumps and motors for construction machinery and vehicles are discussed. A bent axis type axial double piston pump for negative feedback control systems and a cam plate type double piston pump superior in responsibility for load sensing control systems are usually used for hydraulic shovels. A split flow type double piston pump is on the increase for mini-shovels, having an unsolved problem as pressure fluctuation. The use of piston pumps is increasing rapidly for cranes, and a cam plate type axial piston pump is mainly used for large cranes. A traveling motor integrated with a transmission gear is usually used for hydraulic shovels, and a swing motor with valves and a brake in its casing is also used. A bent axis type variable displacement motor combined with a transmission is on the increase for winches, and a reliable preventing system from drop of suspended loading is expected to be developed rapidly. HST for traveling is also diffusing into small construction machinery. 12 figs.

Non-adiabatic pumping in an oscillating-piston model

Science.gov (United States)

Chuchem, Maya; Dittrich, Thomas; Cohen, Doron

2012-05-01

We consider the prototypical "piston pump" operating on a ring, where a circulating current is induced by means of an AC driving. This can be regarded as a generalized Fermi-Ulam model, incorporating a finite-height moving wall (piston) and non-trivial topology (ring). The amount of particles transported per cycle is determined by a layered structure of phase space. Each layer is characterized by a different drift velocity. We discuss the differences compared with the adiabatic and Boltzmann pictures, and highlight the significance of the "diabatic" contribution that might lead to a counter-stirring effect.

Unsteady response of flow system around balance piston in a rocket pump

Science.gov (United States)

Kawasaki, S.; Shimura, T.; Uchiumi, M.; Hayashi, M.; Matsui, J.

2013-03-01

In the rocket engine turbopump, a self-balancing type of axial thrust balancing system using a balance piston is often applied. In this study, the balancing system in liquid-hydrogen (LH2) rocket pump was modeled combining the mechanical structure and the flow system, and the unsteady response of the balance piston was investigated. The axial vibration characteristics of the balance piston with a large amplitude were determined, sweeping the frequency of the pressure fluctuation on the inlet of the balance piston. This vibration was significantly affected by the compressibility of LH2.

Improvement of the low-speed friction characteristics of a hydraulic piston pump by PVD-coating of TiN

International Nuclear Information System (INIS)

Hong, Yeh Sun; Lee, Sang Yul; Kim, Sung Hun; Lim, Hyun Sik

2006-01-01

The hydraulic pump of an Electro-hydrostatic Actuator should be able to quickly feed large volume of oil into hydraulic cylinder in order to reduce the response time. On the other hand, it should be also able to precisely dispense small amount of oil through low-speed operation so that the steady state position control error of the actuator can be accurately compensated. Within the scope of axial piston type hydraulic pumps, this paper is focused on the investigation how the surface treatment of their cylinder barrel with TiN plasma coating can contribute to the reduction of the friction and wear rate of valve plate in the low-speed range with mixed lubrication. The results showed that the friction torque of the valve plate mated with a TiN-coated cylinder barrel could be reduced to 22% of that with an uncoated original one when load pressure was 300 bar and rotational speed 100 rpm. It means that the torque efficiency of the test pump was expected to increase more than 1.3% under the same working condition. At the same time, the wear rate of the valve plate could be reduced to 40∼50%

Dynamically balanced, hydraulically driven compressor/pump apparatus for resonant free piston Stirling engines

Science.gov (United States)

Corey, John A.

1984-05-29

A compressor, pump, or alternator apparatus is designed for use with a resonant free piston Stirling engine so as to isolate apparatus fluid from the periodically pressurized working fluid of the Stirling engine. The apparatus housing has a first side closed by a power coupling flexible diaphragm (the engine working member) and a second side closed by a flexible diaphragm gas spring. A reciprocally movable piston is disposed in a transverse cylinder in the housing and moves substantially at right angles relative to the flexible diaphragms. An incompressible fluid fills the housing which is divided into two separate chambers by suitable ports. One chamber provides fluid coupling between the power diaphragm of the RFPSE and the piston and the second chamber provides fluid coupling between the gas spring diaphragm and the opposite side of the piston. The working members of a gas compressor, pump, or alternator are driven by the piston. Sealing and wearing parts of the apparatus are mounted at the external ends of the transverse cylinder in a double acting arrangement for accessibility. An annular counterweight is mounted externally of the reciprocally movable piston and is driven by incompressible fluid coupling in a direction opposite to the piston so as to damp out transverse vibrations.

Remaining useful life prediction based on the Wiener process for an aviation axial piston pump

Directory of Open Access Journals (Sweden)

Xingjian Wang

2016-06-01

Full Text Available An aviation hydraulic axial piston pump’s degradation from comprehensive wear is a typical gradual failure model. Accurate wear prediction is difficult as random and uncertain characteristics must be factored into the estimation. The internal wear status of the axial piston pump is characterized by the return oil flow based on fault mechanism analysis of the main frictional pairs in the pump. The performance degradation model is described by the Wiener process to predict the remaining useful life (RUL of the pump. Maximum likelihood estimation (MLE is performed by utilizing the expectation maximization (EM algorithm to estimate the initial parameters of the Wiener process while recursive estimation is conducted utilizing the Kalman filter method to estimate the drift coefficient of the Wiener process. The RUL of the pump is then calculated according to the performance degradation model based on the Wiener process. Experimental results indicate that the return oil flow is a suitable characteristic for reflecting the internal wear status of the axial piston pump, and thus the Wiener process-based method may effectively predicate the RUL of the pump.

Computer controlled titration with piston burette or peristaltic pump - a comparison.

Science.gov (United States)

Hoffmann, W

1996-09-01

The advantages and problems of the use of piston burettes and peristaltic pumps for dosage of titrant solutions in automatic titrations are shown. For comparison, only the dosing devices were exchanged and all other components and conditions remained unchanged. The results of continuous acid base titration show good agreement and comparable reproducibility. Potentiometric sensors (glass electrodes) with different equilibration behaviour influence the results. The capability of such electrodes was tested. Conductometric measurements allow a much faster detection because there is no equilibration of electrodes. Piston burettes should be used for titration with very high precision, titration with organic solvents and slow titrations. Peristaltic pumps seem to be more suitable for continuous titrations and long time operation without service.

The properties of an improvised piston pump for the rapid delivery of intravenous fluids.

Science.gov (United States)

Smart, C M; Primrose, C W; Peters, A L; Speirits, E J

2014-02-01

To maximise the effect of a small fluid load, it is occasionally desirable to bolus manually with multiple depressions of a large-capacity syringe. This is usually achieved by placing the syringe on the side port of a three-way tap. We modified this technique by placing two-one-way valves in line with the three-way tap, effectively creating a piston pump, the infusion rates via which we compared with those achieved by an inflatable pressure-infuser in a simulated resuscitation. Fluid flow was faster using the piston pump than with the pressure-infuser (mean (SD) time to infuse 2000 ml saline 0.9% via a 16-G cannula 352 (10) s vs 495 (19) s, respectively, p piston pump appears to have potential for both tight control of fluid delivery and major high-volume resuscitation. The lightweight nature of the pump and its lack of reliance on gravity may also make it suitable for the pre-hospital setting. © 2014 The Association of Anaesthetists of Great Britain and Ireland.

Preliminary Study of a Piston Pump for Cryogenic Fluids

Science.gov (United States)

Biermann, Arnold E.; Kohl, Robert C.

1959-01-01

Preliminary data are presented covering the performance of a low-speed, five-cylinder piston pump designed for handling boiling hydrogen. This pump was designed for a flow of 55 gallons per minute at 240 rpm with a discharge pressure of 135 pounds per square inch. Tests were made using JP-4 fuel, liquid nitrogen, and liquid hydrogen. Pump delivery and endurance characteristics were satisfactory for the range of operation covered. In connection with the foregoing pump development, the cavitation characteristics of a preliminary visual model, glass-cylinder pump and of a simple reciprocating disk were studied. Subcooling of approximately 0.60 F was obtained from the cavitation produced by reciprocating a disk in boiling nitrogen and in boiling water. The subcooling obtained in a similar manner with liquid hydrogen was somewhat less.

An adaptive-order particle filter for remaining useful life prediction of aviation piston pumps

Directory of Open Access Journals (Sweden)

Tongyang LI

2018-05-01

Full Text Available An accurate estimation of the remaining useful life (RUL not only contributes to an effective application of an aviation piston pump, but also meets the necessity of condition based maintenance (CBM. For the current RUL evaluation methods, a model-based method is inappropriate for the degradation process of an aviation piston pump due to difficulties of modeling, while a data-based method rarely presents high-accuracy prediction in a long period of time. In this work, an adaptive-order particle filter (AOPF prognostic process is proposed aiming at improving long-term prediction accuracy of RUL by combining both kinds of methods. A dynamic model is initialized by a data-driven or empirical method. When a new observation comes, the prior state distribution is approximated by a current model. The order of the current model is updated adaptively by fusing the information of the observation. Monte Carlo simulation is employed for estimating the posterior probability density function of future states of the pump’s degradation. With updating the order number adaptively, the method presents a higher precision in contrast with those of traditional methods. In a case study, the proposed AOPF method is adopted to forecast the degradation status of an aviation piston pump with experimental return oil flow data, and the analytical results show the effectiveness of the proposed AOPF method. Keywords: Adaptive prognosis, Condition based maintenance (CBM, Particle filter (PF, Piston pump, Remaining useful life (RUL

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

Directory of Open Access Journals (Sweden)

Ye-qing Huang

2016-01-01

Full Text Available 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.

Fundamentals of hydraulic piston pump applications in chemical engineering; Verfahrenstechnische Grundsaetze beim Einsatz von hydraulischen Kolbenpumpen

Energy Technology Data Exchange (ETDEWEB)

Haubold, H.J. [Putzmeister AG, Putzmeister Industrial Technology (PIT), Aichtal (Germany)

2007-07-01

This paper describes design features as well as criteria for the selection of the required piston pump under the circumstance of high viscose sludge. These kind of sludges are mostly contaminated with foreign bodies. Life cycle costs and professional service management are influencing factors of a successful pump operation. This paper will show in detail criteria's for the pipe transportation. For example the influence of the calculation for the pressure loss against the necessary pump pressure. In focus are all structural measures to reduce pressure peaks, as well as the reduction of pressure variation and their elimination in the delivery flow. This under the circumstance of a high pulsating pump delivery. This paper will be concluded with a reference of examples of applications and show new developments of piston pump design. (orig.)

Fluid Dynamics in Rotary Piston Blood Pumps.

Science.gov (United States)

Wappenschmidt, Johannes; Sonntag, Simon J; Buesen, Martin; Gross-Hardt, Sascha; Kaufmann, Tim; Schmitz-Rode, Thomas; Autschbach, Ruediger; Goetzenich, Andreas

2017-03-01

Mechanical circulatory support can maintain a sufficient blood circulation if the native heart is failing. The first implantable devices were displacement pumps with membranes. They were able to provide a sufficient blood flow, yet, were limited because of size and low durability. Rotary pumps have resolved these technical drawbacks, enabled a growing number of mechanical circulatory support therapy and a safer application. However, clinical complications like gastrointestinal bleeding, aortic insufficiency, thromboembolic complications, and impaired renal function are observed with their application. This is traced back to their working principle with attenuated or non-pulsatile flow and high shear stress. Rotary piston pumps potentially merge the benefits of available pump types and seem to avoid their complications. However, a profound assessment and their development requires the knowledge of the flow characteristics. This study aimed at their investigation. A functional model was manufactured and investigated with particle image velocimetry. Furthermore, a fluid-structure interaction computational simulation was established to extend the laboratory capabilities. The numerical results precisely converged with the laboratory measurements. Thus, the in silico model enabled the investigation of relevant areas like gap flows that were hardly feasible with laboratory means. Moreover, an economic method for the investigation of design variations was established.

Operational experience with double acting piston pumps for cryogenic helium and nitrogen

International Nuclear Information System (INIS)

Vosswinkel, F.

1978-01-01

The design of a high efficiency double acting piston pump suitable for pumping liquefied gases at cryogenic temperatures for cable cooling, is reported. The pump has proved flexible, reliable and efficient in operation. The plunger-type pumps can be used for filling cryostats or dewars with liquid helium or nitrogen from a pressure free or pressurized storage vessel, or as circulators for subcooled, saturated and/or supercritical helium in large scale cooling experiments. Flow rates of up to 17 g/s, maximum operating pressure of 600 kPa absolute and maximum differential pressure of approximately 100 kPa are obtained. (UK)

Piston-Skirt Lubrication System For Compressor

Science.gov (United States)

Schroeder, Edgar C.; Burzynski, Marion, Jr.

1994-01-01

Piston-skirt lubrication system provides steady supply of oil to piston rings of gas compressor. No need for oil-filled crankcase or external oil pump. Instead, part of each piston acts as its own oil pump circulating oil from reservoir. Annular space at bottom of piston and cylinder constitutes working volume of small oil pump. Depending on application, reservoir open to atmosphere, or sealed and pressurized in bellows to prevent contact between oil and atmosphere. Filter removes particles worn away from piston rings and cylinder wall during normal operation.

Mechanical design and modeling of a single-piston pump for the novel power take-off system of a wave energy converter

NARCIS (Netherlands)

Vakis, Antonis I.; Anagnostopoulos, John S.

2016-01-01

A multi-pump, multi-piston power take-off wave energy converter ((MPPTO)-P-2 WEC) has been proposed for use with a novel renewable energy harvester termed the Ocean Grazer. The (MPPTO)-P-2 WEC utilizes wave motion to pump via buoys connected to pistons working fluid within a closed circuit and store

Free piston inertia compressor

Science.gov (United States)

Richards, W.D.C.; Bilodeau, D.; Marusak, T.; Dutram, L. Jr.; Brady, J.

A free piston inertia compressor comprises a piston assembly including a connecting rod having pistons on both ends, the cylinder being split into two substantially identical portions by a seal through which the connecting rod passes. Vents in the cylinder wall are provided near the seal to permit gas to escape the cylinder until the piston covers the vent whereupon the remaining gas in the cylinder functions as a gas spring and cushions the piston against impact on the seal. The connecting rod has a central portion of relatively small diameter providing free play of the connecting rod through the seal and end portions of relatively large diameter providing a limited tolerance between the connecting rod and the seal. Finally, the seal comprises a seal ring assembly consisting of a dampener plate, a free floating seal at the center of the dampener plate and a seal retainer plate in one face of the dampener plate.

Energetics of the Ventilatory Piston Pump of the Lugworm, a Deposit-feeding Polychaete Living in a Burrow.

Science.gov (United States)

Toulmond, A; Dejours, P

1994-04-01

The aim of this study was to tentatively estimate the energy cost of breathing in the lugworm, Arenicola marina (L.), a gallery-dwelling, piston-pump breather that moves water in a tail-to-head direction. Each tested lugworm was placed in a horizontal glass tube. The caudal end of the tube was connected to a well-aerated seawater reservoir at 20{deg}C, and the cephalic end attached to a drop meter through a tube resistance. At the exit of the cephalic chamber the O2 tension was recorded via an in situ O2 electrode, and the hydrostatic pressure of the exhaled water was also recorded. Water flow rate, total O2 uptake rate {Mdot}TOTO2, O2 extraction coefficient, and the mechanical power necessary to pump water through the resistive anterior exit of the apparatus ({Wdot}MEC), were computed. The basal metabolic rate of each animal ({Mdot}CONFO2) was separately estimated by the confinement method. {Mdot}CONFO2 subtracted from {Mdot}TOTO2 approximates {Mdot}CBO2, the O2 uptake rate necessary to activate the piston-pump breathing mechanism and to ensure the corresponding mechanical work rate, {Wdot}MEC. The results show that the energy cost of breathing, {Mdot}CBO2, of the piston-pump-breathing Arenicola is very high, with mean values approximating 47% of the {Mdot}TOTO2 value; that the mechanical power we measured, {Wdot}MEC, is very low; and that the mechanical-to-metabolic efficiency, the ratio {Wdot}MEC/{Mdot}CBO2, does not exceed 1%. These observations are compared to those obtained in other piston-pump breathers, such as Chaetopterus variopedatus and Urechis caupo, and in ciliary filter feeders including polychaetes, bivalves, and ascidians.

Modeling and performance improvement of the constant power regulator systems in variable displacement axial piston pump.

Science.gov (United States)

Park, Sung Hwan; Lee, Ji Min; Kim, Jong Shik

2013-01-01

An irregular performance of a mechanical-type constant power regulator is considered. In order to find the cause of an irregular discharge flow at the cut-off pressure area, modeling and numerical simulations are performed to observe dynamic behavior of internal parts of the constant power regulator system for a swashplate-type axial piston pump. The commercial numerical simulation software AMESim is applied to model the mechanical-type regulator with hydraulic pump and simulate the performance of it. The validity of the simulation model of the constant power regulator system is verified by comparing simulation results with experiments. In order to find the cause of the irregular performance of the mechanical-type constant power regulator system, the behavior of main components such as the spool, sleeve, and counterbalance piston is investigated using computer simulation. The shape modification of the counterbalance piston is proposed to improve the undesirable performance of the mechanical-type constant power regulator. The performance improvement is verified by computer simulation using AMESim software.

Application of the free piston concept to Vuilleumier heat pumps

Energy Technology Data Exchange (ETDEWEB)

Ruether, J.; Kuehl, H.D.; Schulz, S. [Dortmund Univ. (Germany). Inst. fuer Thermodynamik

2000-07-01

In this contribution the 64 different possible set-ups of the oscillation system for the two displacers of a {beta}-type free piston Vuilleumier heat pump are discussed. Many of these alternatives can be disregarded as they are unable to oscillate in a self-sustaining mode. To decide about this ability the differential equations describing the system dynamics are derived. For simplicity reasons damping is neglected. Furthermore some practical aspects and the starting behaviour of the machine are taken into account. Based on this analysis the best configuration was chosen to be realised as a modification of the FPV2 free piston Vuilleumier heat pump. The new design is described and first experimental results of the modified version are presented. (orig.) [German] Ausgehend von der Gesamtheit aller moeglichen Schwingungssysteme fuer das Kolbensystem einer Freikolben-Vuilleumier-Waermepumpe wird der Weg zu einem fuer den Einsatz in der Heizungstechnik geeigneten Konzept beschrieben. Wesentliches Kriterium ist dabei die Faehigkeit zur selbsterregten Schwingung, die anhand der die Kinematik des Systems beschreibenden Differentialgleichungen beurteilt wird. Dabei kann der Einfluss der Daempfung unberuecksichtigt bleiben. Praktische Ueberlegungen und insbesondere das Startverhalten der entsprechenden Konfigurationen werden ebenfalls beruecksichtigt. Das auf Grundlage der obigen Kriterien ausgewaehlte Kolbensystem wird durch Modifikation der FPV2 Freikolben-Vuilleumier-Waermepumpe realisiert. Entsprechende Umbauarbeiten sowie erste Betriebserfahrungen und Messdaten werden vorgestellt. (orig.)

Modeling and Performance Improvement of the Constant Power Regulator Systems in Variable Displacement Axial Piston Pump

Science.gov (United States)

Park, Sung Hwan; Lee, Ji Min; Kim, Jong Shik

2013-01-01

An irregular performance of a mechanical-type constant power regulator is considered. In order to find the cause of an irregular discharge flow at the cut-off pressure area, modeling and numerical simulations are performed to observe dynamic behavior of internal parts of the constant power regulator system for a swashplate-type axial piston pump. The commercial numerical simulation software AMESim is applied to model the mechanical-type regulator with hydraulic pump and simulate the performance of it. The validity of the simulation model of the constant power regulator system is verified by comparing simulation results with experiments. In order to find the cause of the irregular performance of the mechanical-type constant power regulator system, the behavior of main components such as the spool, sleeve, and counterbalance piston is investigated using computer simulation. The shape modification of the counterbalance piston is proposed to improve the undesirable performance of the mechanical-type constant power regulator. The performance improvement is verified by computer simulation using AMESim software. PMID:24282389

Modeling and Performance Improvement of the Constant Power Regulator Systems in Variable Displacement Axial Piston Pump

Directory of Open Access Journals (Sweden)

Sung Hwan Park

2013-01-01

Full Text Available An irregular performance of a mechanical-type constant power regulator is considered. In order to find the cause of an irregular discharge flow at the cut-off pressure area, modeling and numerical simulations are performed to observe dynamic behavior of internal parts of the constant power regulator system for a swashplate-type axial piston pump. The commercial numerical simulation software AMESim is applied to model the mechanical-type regulator with hydraulic pump and simulate the performance of it. The validity of the simulation model of the constant power regulator system is verified by comparing simulation results with experiments. In order to find the cause of the irregular performance of the mechanical-type constant power regulator system, the behavior of main components such as the spool, sleeve, and counterbalance piston is investigated using computer simulation. The shape modification of the counterbalance piston is proposed to improve the undesirable performance of the mechanical-type constant power regulator. The performance improvement is verified by computer simulation using AMESim software.

Experimental Verification of Oil Whirl of Piston in Axial Piston Pmmp and Motor

OpenAIRE

田中, 嘉津彦; 中原, 綱光; 京極, 啓史

1999-01-01

Piston motion which interacts with lubrication characteristics including friction force between the piston and cylinder has been measured in order to prove the oil whirl phenomena in an axial piston pump and motor which had been found theoretically in the previous paper. The piston motion has been measured by means of eddy current displacement sensors, comparing with calculated results. It has been verified that the piston has whirled in the cylinder under certain operating conditions and spe...

Uji Unjuk Kerja Pompa Pedal Multi Piston

OpenAIRE

Sukwanputra, Firman Yoko; Soegihardjo, Oegik

2003-01-01

Multi piston pedal pump is classified under reciprocating pump. This pump is generally designed for applications that require high capacity with low head. This pump is used for shallow well or to pump water in the system with low static and dynamic head. This experiment will examine the performance of multi piston pedal pump with capacity 3000 liter/hour. Two parameters, volumetric efficiency and overall efficiency will be examined during the experiment. The goal is to know the actual perform...

3D-CFD Simulation of Confined Cross-Flow Injection Process Using Single Piston Pump

Directory of Open Access Journals (Sweden)

M. Elashmawy

2017-12-01

Full Text Available Injection process into a confined cross flow is quite important for many applications including chemical engineering and water desalination technology. The aim of this study is to investigate the performance of the injection process into a confined cross-flow of a round pipe using a single piston injection pump. A computational fluid dynamics (CFD analysis has been carried out to investigate the effect of the locations of the maximum velocity and minimum pressure on the confined cross-flow process. The jet trajectory is analyzed and related to the injection pump shaft angle of rotation during the injection duty cycle by focusing on the maximum instant injection flow of the piston action. Results indicate a low effect of the jet trajectory within the range related to the injection pump operational conditions. Constant cross-flow was used and injection flow is altered to vary the jet to line flow ratio (QR. The maximum jet trajectory exhibits low penetration inside the cross-flow. The results showed three regions of the flow ratio effect zones with different behaviors. Results also showed that getting closer to the injection port causes a significant decrease on the locations of the maximum velocity and minimum pressure.

Load of the slipper-swash plate kinematic pair of an axial piston pump

Directory of Open Access Journals (Sweden)

Złoto Tadeusz

2018-01-01

Full Text Available The paper presents problems related to the twisting moment of the slipper. The load of the slipper and the piston has been presented and the complex formula of twisting moment of the slipper has been established. Achieved results has been presented graphically. The conducted research has indicated that the value of the twisting moment relays on both the exploitation and geometrical parameters.

Summary of Test Results From a 1 kWe-Class Free-Piston Stirling Power Convertor Integrated With a Pumped NaK Loop

Science.gov (United States)

Briggs, Maxwell H.; Geng, Steven M.; Pearson, J. Boise; Godfroy, Thomas J.

2010-01-01

As a step towards development of Stirling power conversion for potential use in Fission Surface Power (FSP) systems, a pair of commercially available 1 kW class free-piston Stirling convertors was modified to operate with a NaK liquid metal pumped loop for thermal energy input. This was the first-ever attempt at powering a free-piston Stirling engine with a pumped liquid metal heat source and is a major FSP project milestone towards demonstrating technical feasibility. The tests included performance mapping the convertors over various hot and cold-end temperatures, piston amplitudes and NaK flow rates; and transient test conditions to simulate various start-up and fault scenarios. Performance maps of the convertors generated using the pumped NaK loop for thermal input show increases in power output over those measured during baseline testing using electric heating. Transient testing showed that the Stirling convertors can be successfully started in a variety of different scenarios and that the convertors can recover from a variety of fault scenarios.

Impact of typical steady-state conditions and transient conditions on flow ripple and its test accuracy for axial piston pump

Science.gov (United States)

Xu, Bing; Hu, Min; Zhang, Junhui

2015-09-01

The current research about the flow ripple of axial piston pump mainly focuses on the effect of the structure of parts on the flow ripple. Therein, the structure of parts are usually designed and optimized at rated working conditions. However, the pump usually has to work in large-scale and time-variant working conditions. Therefore, the flow ripple characteristics of pump and analysis for its test accuracy with respect to variant steady-state conditions and transient conditions in a wide range of operating parameters are focused in this paper. First, a simulation model has been constructed, which takes the kinematics of oil film within friction pairs into account for higher accuracy. Afterwards, a test bed which adopts Secondary Source Method is built to verify the model. The simulation and tests results show that the angular position of the piston, corresponding to the position where the peak flow ripple is produced, varies with the different pressure. The pulsating amplitude and pulsation rate of flow ripple increase with the rise of pressure and the variation rate of pressure. For the pump working at a constant speed, the flow pulsation rate decreases dramatically with the increasing speed when the speed is less than 27.78% of the maximum speed, subsequently presents a small decrease tendency with the speed further increasing. With the rise of the variation rate of speed, the pulsating amplitude and pulsation rate of flow ripple increase. As the swash plate angle augments, the pulsating amplitude of flow ripple increases, nevertheless the flow pulsation rate decreases. In contrast with the effect of the variation of pressure, the test accuracy of flow ripple is more sensitive to the variation of speed. It makes the test accuracy above 96.20% available for the pulsating amplitude of pressure deviating within a range of ±6% from the mean pressure. However, with a variation of speed deviating within a range of ±2% from the mean speed, the attainable test

Design Study for a Free-piston Vuilleumier Cycle Heat Pump

Science.gov (United States)

Matsue, Junji; Hoshino, Norimasa; Ikumi, Yonezou; Shirai, Hiroyuki

Conceptual design for a free-piston Vuilleumier cycle heat pump machine was proposed. The machine was designed based upon the numerical results of a dynamic analysis method. The method included the effect of self excitation vibration with dissipation caused by the flow friction of an oscillating working gas flow and solid friction of seals. It was found that the design values of reciprocating masses and spring constants proposed in published papers related to this study were suitable for practical use. The fundamental effects of heat exchanger elements on dynamic behaviors of the machine were clarified. It has been pointed out that some improvements were required for thermodynamic analysis of heat exchangers and working spaces.

A Hybrid Lumped Parameters/Finite Element/Boundary Element Model to Predict the Vibroacoustic Characteristics of an Axial Piston Pump

Directory of Open Access Journals (Sweden)

Shaogan Ye

2017-01-01

Full Text Available Low noise axial piston pumps become the rapid increasing demand in modern hydraulic fluid power systems. This paper proposes a systematic approach to simulate the vibroacoustic characteristics of an axial piston pump using a hybrid lumped parameters/finite element/boundary element (LP/FE/BE model, and large amount of experimental work was performed to validate the model. The LP model was developed to calculate the excitation forces and was validated by a comparison of outlet flow ripples. The FE model was developed to calculate the vibration of the pump, in which the modeling of main friction pairs using different spring elements was presented in detail, and the FE model was validated using experimental modal analysis and measured vibrations. The BE model was used to calculate the noise emitted from the pump, and a measurement of sound pressure level at representative field points in a hemianechoic chamber was conducted to validate the BE model. Comparisons between the simulated and measured results show that the developed LP/FE/BE model is effective in capturing the vibroacoustic characteristics of the pump. The presented approach can be extended to other types of fluid power components and contributes to the development of quieter fluid power systems.

Test Results From a Pair of 1-kWe Dual-Opposed Free-Piston Stirling Power Convertors Integrated With a Pumped NaK Loop

Science.gov (United States)

Geng, Steven M.; Briggs, Maxwell H.; Penswick, L. Barry; Pearson, J. Boise; Godfroy, Thomas J.

2011-01-01

As a step towards development of Stirling power conversion for potential use in Fission Surface Power (FSP) systems, a pair of commercially available 1-kW-class free-piston Stirling convertors were modified to operate with a NaK (sodium (Na) and potassium (K)) liquid metal pumped loop for thermal energy input. This was the first-ever attempt at powering a free-piston Stirling engine with a pumped liquid metal heat source and is a major FSP project milestone towards demonstrating technical feasibility. The convertors were successfully tested at the Marshall Space Flight Center (MSFC) from June 6 through July 14, 2009. The convertors were operated for a total test time of 66 hr and 16 min. The tests included (a) performance mapping the convertors over various hot- and cold-end temperatures, piston amplitudes, and NaK flow rates and (b) transient test conditions to simulate various startup (i.e., low-, medium-, and high-temperature startups) and fault scenarios (i.e., loss of heat source, loss of NaK pump, convertor stall, etc.). This report documents the results of this testing

Analysis and dynamical modeling of a piston valve for a wave energy converter

OpenAIRE

Cruz Gispert, Albert

2014-01-01

The Ocean Grazer, a novel wave energy converter, has been proposed by the University of Groningen. The system can collect and store multiple forms of ocean energy, with a pistontype hydraulic pump as its core technology. In this work, the dynamical behavior of a piston valve for use in the piston pump system is studied. In order to gain insight into the dynamical behavior of the piston-type hydraulic pump, a simulation model is developed to describe the movement of the piston v...

Summary of Test Results From a 1 kW(sub e)-Class Free-Piston Stirling Power Convertor Integrated With a Pumped NaK Loop

Science.gov (United States)

Briggs, Maxwell H.; Geng, Steven M.; Pearson, J. Boise; Godfroy, Thomas J.

2010-01-01

As a step towards development of Stirling power conversion for potential use in Fission Surface Power (FSP) systems, a pair of commercially available 1 kW class free-piston Stirling convertors was modified to operate with a NaK liquid metal pumped loop for thermal energy input. This was the first-ever attempt at powering a free-piston Stirling engine with a pumped liquid metal heat source and is a major FSP project milestone towards demonstrating technical feasibility. The tests included performance mapping the convertors over various hot and cold-end temperatures, piston amplitudes and NaK flow rates; and transient test conditions to simulate various start-up and fault scenarios. Performance maps of the convertors generated using the pumped NaK loop for thermal input show increases in power output over those measured during baseline testing using electric heating. Transient testing showed that the Stirling convertors can be successfully started in a variety of different scenarios and that the convertors can recover from a variety of fault scenarios.

Flow ripple reduction of an axial piston pump by a combination of cross-angle and pressure relief grooves: Analysis and optimization

International Nuclear Information System (INIS)

Xu, Bing; Ye, Shaogan; Zhang, Junhui; Zhang, Chunfeng

2016-01-01

This paper investigates the potential of flow ripple reduction of an axial piston pump by a combination of cross-angle and pressure relief grooves. A dynamic model is developed to analyze the pumping dynamics of the pump and validated by experimental results. The effects of cross-angle on the flow ripples in the outlet and inlet ports, and the piston chamber pressure are investigated. The effects of pressure relief grooves on the optimal solutions obtained by a multi-objective optimization method are identified. A sensitivity analysis is performed to investigate the sensitivity of cross-angle to different working conditions. The results reveal that the flow ripples from the optimal solutions are smaller using the cross-angle and pressure relief grooves than those using the cross-angle and ordinary precompression and decompression angles and the cross-angle can be smaller. In addition, when the optimal design is used, the outlet flow ripples sensitivity can be reduced significantly.

A prototype of volume-controlled tidal liquid ventilator using independent piston pumps.

Science.gov (United States)

Robert, Raymond; Micheau, Philippe; Cyr, Stéphane; Lesur, Olivier; Praud, Jean-Paul; Walti, Hervé

2006-01-01

Liquid ventilation using perfluorochemicals (PFC) offers clear theoretical advantages over gas ventilation, such as decreased lung damage, recruitment of collapsed lung regions, and lavage of inflammatory debris. We present a total liquid ventilator designed to ventilate patients with completely filled lungs with a tidal volume of PFC liquid. The two independent piston pumps are volume controlled and pressure limited. Measurable pumping errors are corrected by a programmed supervisor module, which modifies the inserted or withdrawn volume. Pump independence also allows easy functional residual capacity modifications during ventilation. The bubble gas exchanger is divided into two sections such that the PFC exiting the lungs is not in contact with the PFC entering the lungs. The heating system is incorporated into the metallic base of the gas exchanger, and a heat-sink-type condenser is placed on top of the exchanger to retrieve PFC vapors. The prototype was tested on 5 healthy term newborn lambs (<5 days old). The results demonstrate the efficiency and safety of the prototype in maintaining adequate gas exchange, normal acido-basis equilibrium, and cardiovascular stability during a short, 2-hour total liquid ventilator. Airway pressure, lung volume, and ventilation scheme were maintained in the targeted range.

Piston-pump-type high frequency oscillatory ventilation for neonates with congenital diaphragmatic hernia: a new protocol.

Science.gov (United States)

Tamura, M; Tsuchida, Y; Kawano, T; Honna, T; Ishibashi, R; Iwanaka, T; Morita, Y; Hashimoto, H; Tada, H; Miyasaka, K

1988-05-01

High frequency ventilation and extracorporeal membrane oxygenation (ECMO) are devices that are expected to save the lives of newborn infants whose pulmonary conditions have deteriorated. A piston-pump-type high-frequency oscillator (HFO), developed by Bryan and Miyasaka called "Hummingbird," is considered to be superior to high frequency "jet" ventilators or those of the flow-interrupter type, and was used successfully in two neonates with congenital diaphragmatic hernia (CDH) in a high-risk group. The first baby was on a conventional ventilator with pharmacologic support for the first 54 hours and then operated on. Postoperative deterioration necessitated the use of HFO for the next eight days. The infant then recovered uneventfully. For the second baby, HFO was necessary both preoperatively and postoperatively. This baby had a major diaphragmatic defect and her case was complicated with pneumothorax. There was a long stormy course on HFO (total, 70 days), but the patient was successfully extubated on the 75th day postoperatively and is now doing well. We believe active long preoperative stabilization with pharmacologic support and preoperative and postoperative hyperventilation with a piston-pump-type HFO may be a new innovative strategy for the management of severe CDH patients.

Pump safety device

International Nuclear Information System (INIS)

Timmermans, Francis; Vandervorst, Jean.

1981-01-01

Safety device for longitudinally leak proofing the shaft of a pump in the event of the fracture of the dynamic seal separating the pump fluid high pressure chamber from the low pressure chamber. It is designed for fitting to the primary pumps of nuclear reactors. It includes a hollow cyclindrical piston located coaxially around the pump shaft and normally housed in a chamber provided for this purpose in the fixed housing of the dynamic seal, and means for moving this piston coaxially so as to compress a safety O ring between the shaft and the piston in the event of the dynamic seal failing [fr

Hydraulic Pump Fault Diagnosis Control Research Based on PARD-BP Algorithm

Directory of Open Access Journals (Sweden)

LV Dongmei

2014-12-01

Full Text Available Combining working principle and failure mechanism of RZU2000HM hydraulic press, with its present fault cases being collected, the working principle of the oil pressure and faults phenomenon of the hydraulic power unit –swash-plate axial piston pump were studied with some emphasis, whose faults will directly affect the dynamic performance of the oil pressure and flow. In order to make hydraulic power unit work reliably, PARD-BP (Pruning Algorithm based Random Degree neural network fault algorithm was introduced, with swash-plate axial piston pump’s vibration fault sample data regarded as input, and fault mode matrix regarded as target output, so that PARD-BP algorithm could be trained. In the end, the vibration results were verified by the vibration modal test, and it was shown that the biggest upward peaks of vacuum pump in X-direction, Y-direction and Z- direction have fallen by 30.49 %, 21.13 % and 18.73 % respectively, so that the reliability of the fact that PARD-BP algorithm could be used for the online fault detection and diagnosis of the hydraulic pump was verified.

The provision of clearances accuracy in piston - cylinder mating

Science.gov (United States)

Glukhov, V. I.; Shalay, V. V.

2017-08-01

The paper is aimed at increasing the quality of the pumping equipment in oil and gas industry. The main purpose of the study is to stabilize maximum values of productivity and durability of the pumping equipment based on the selective assembly of the cylinder-piston kinematic mating by optimization criterion. It is shown that the minimum clearance in the piston-cylinder mating is formed by maximum material dimensions. It is proved that maximum material dimensions are characterized by their own laws of distribution within the tolerance limits for the diameters of the cylinder internal mirror and the outer cylindrical surface of the piston. At that, their dispersion zones should be divided into size groups with a group tolerance equal to half the tolerance for the minimum clearance. The techniques for measuring the material dimensions - the smallest cylinder diameter and the largest piston diameter according to the envelope condition - are developed for sorting them into size groups. Reliable control of the dimensions precision ensures optimal minimum clearances of the piston-cylinder mating in all the size groups of the pumping equipment, necessary for increasing the equipment productivity and durability during the production, operation and repair processes.

Thermomechanical piston pump development

Science.gov (United States)

Sabelman, E. E.

1971-01-01

A thermally powered reciprocating pump has been devised to replace or augment an electric pump for the transport of temperature-control fluid on the Thermoelectric Outer Planet Spacecraft (TOPS). The thermally powered pump operates cyclically by extracting heat energy from the fluid by means of a vapor-pressure expansion system and by using the heat to perform the mechanical work of pumping. A feasibility test unit has been constructed to provide an output of 7 cu in during a 10- to 100-second cycle. It operates with a fluid input temperature of 200 to 300 F and a heat sink temperature of 0 to 30 F.

Investigating the adaptability of the multi-pump multi-piston power take-off system for a novel wave energy converter

NARCIS (Netherlands)

Wei, Y.; Barradas Berglind, J.J; van Rooij, M.; Prins, WA; Jayawardhana, B.; Vakis, A. I.

2017-01-01

In this work, a numerical model is developed in order to investigate the adaptability of the multi-pump multi-piston power take-off ((MPPTO)-P-2) system of a novel wave energy converter (WEC). This model is realized in the MATLAB/SIMULINK environment, using the multi-body dynamics solver Multibody

Analysis of BY-106 pump pit cover plate

International Nuclear Information System (INIS)

Coverdell, B.L.

1994-01-01

A new cover for the pump pit of Tank 241-BY-106 has been designed to allow the rotary core exhauster to be hooked up without requiring pit entry, riser modification, or equipment removal. The new pit cover is necessary to allow installation of two risers for reducing exposure, contamination, and waste. Computer analysis indicates that the safety margin of the pit cover plate with two risers is adequate. The computer stress model and input files are attached. The pit cover plate is a replacement for an existing plate; therefore seismic and wind loads were considered for the plate only

Fundamental test results of a hydraulic free piston internal combustion engine

Energy Technology Data Exchange (ETDEWEB)

Hibi, A.; Ito, T. [Toyohashi University of Technology (Japan). Dept. of Mechanical Engineering

2004-10-01

The hydraulic free piston internal combustion engine pump that has been constructed and tested in this work is the opposed piston, two-stroke cycle, uniflow scavenging, direct fuel injection, and compression ignition type. The opposed engine pistons reciprocate the hydraulic pump pistons directly and the hydraulic power to be used in the hydraulic motors is generated. The hydraulic pressure generated is substantially constant. The opposed free pistons rest after every gas cycle and hydraulic power is continuously supplied by a hydraulic accumulator during the free pistons' rest. The smaller the hydraulic flow output, the longer the duration of the rest. Every gas cycle is performed under a fixed working condition independent of hydraulic power output. The test results in this work indicate that the number of gas cycles per second of the free piston engine pump is directly proportional to hydraulic flow output. The opposed free pistons operate every 53.2 s when hydraulic flow output is 1.02 cm{sup 3}/s; at that time hydraulic power output is 0.0124 kW. Hydraulic thermal efficiency, the ratio of hydraulic energy produced to fuel energy consumed, has been measured in the range 0.0124 kW to 4.88 kW of hydraulic power output and it has become clear that hydraulic thermal efficiency in this range is constant. The measured value of hydraulic thermal efficiency is 31 per cent. It has been demonstrated that hydraulic thermal efficiency is kept constant even if hydraulic power output is very small. (author)

Fuel savings with conventional hot water space heating systems by incorporating a natural gas powered heat pump. Preliminary project: Development of heat pump technology

Science.gov (United States)

Vanheyden, L.; Evertz, E.

1980-12-01

Compression type air/water heat pumps were developed for domestic heating systems rated at 20 to 150 kW. The heat pump is driven either by a reciprocating piston or rotary piston engine modified to operate on natural gas. Particular features of natural gas engines as prime movers, such as waste heat recovery and variable speed, are stressed. Two systems suitable for heat pump operation were selected from among five different mass produced car engines and were modified to incorporate reciprocating piston compressor pairs. The refrigerants used are R 12 and R 22. Test rig data transferred to field conditions show that the fuel consumption of conventional boilers can be reduced by 50% and more by the installation of engine driven heat pumps. Pilot heat pumps based on a 1,600 cc reciprocating piston engine were built for heating four two-family houses. Pilot pump operation confirms test rig findings. The service life of rotary piston and reciprocating piston engines was investigated. The tests reveal characteristic curves for reciprocating piston engines and include exhaust composition measurements.

Positive Darwinian selection in the piston that powers proton pumps in complex I of the mitochondria of Pacific salmon.

Science.gov (United States)

Garvin, Michael R; Bielawski, Joseph P; Gharrett, Anthony J

2011-01-01

The mechanism of oxidative phosphorylation is well understood, but evolution of the proteins involved is not. We combined phylogenetic, genomic, and structural biology analyses to examine the evolution of twelve mitochondrial encoded proteins of closely related, yet phenotypically diverse, Pacific salmon. Two separate analyses identified the same seven positively selected sites in ND5. A strong signal was also detected at three sites of ND2. An energetic coupling analysis revealed several structures in the ND5 protein that may have co-evolved with the selected sites. These data implicate Complex I, specifically the piston arm of ND5 where it connects the proton pumps, as important in the evolution of Pacific salmon. Lastly, the lineage to Chinook experienced rapid evolution at the piston arm.

Positive Darwinian Selection in the Piston That Powers Proton Pumps in Complex I of the Mitochondria of Pacific Salmon

Science.gov (United States)

Garvin, Michael R.; Bielawski, Joseph P.; Gharrett, Anthony J.

2011-01-01

The mechanism of oxidative phosphorylation is well understood, but evolution of the proteins involved is not. We combined phylogenetic, genomic, and structural biology analyses to examine the evolution of twelve mitochondrial encoded proteins of closely related, yet phenotypically diverse, Pacific salmon. Two separate analyses identified the same seven positively selected sites in ND5. A strong signal was also detected at three sites of ND2. An energetic coupling analysis revealed several structures in the ND5 protein that may have co-evolved with the selected sites. These data implicate Complex I, specifically the piston arm of ND5 where it connects the proton pumps, as important in the evolution of Pacific salmon. Lastly, the lineage to Chinook experienced rapid evolution at the piston arm. PMID:21969854

Immersion piston for producing crude oil and liquids from boreholes

Energy Technology Data Exchange (ETDEWEB)

Fekete, I; Hornyos, J

1967-02-09

When using a free piston to pump an oil well, oil and gas accumulates above and below the piston; upon venting the gas pressure above the piston, the gas pressure below it drives the piston and the oil above it to the surface. In the past, such pistons were too heavy and did not run tight in the tubing, causing loss of efficiency and high gas consumption. According to this invention, the piston is made of aluminum or plastic; it consists of at least 2 parts flexibly connected by wire rope or plastic strings, and is equipped with a labyrinth gasket and a paraffin scraper. (3 claims)

Positive Darwinian selection in the piston that powers proton pumps in complex I of the mitochondria of Pacific salmon.

Directory of Open Access Journals (Sweden)

Michael R Garvin

Full Text Available The mechanism of oxidative phosphorylation is well understood, but evolution of the proteins involved is not. We combined phylogenetic, genomic, and structural biology analyses to examine the evolution of twelve mitochondrial encoded proteins of closely related, yet phenotypically diverse, Pacific salmon. Two separate analyses identified the same seven positively selected sites in ND5. A strong signal was also detected at three sites of ND2. An energetic coupling analysis revealed several structures in the ND5 protein that may have co-evolved with the selected sites. These data implicate Complex I, specifically the piston arm of ND5 where it connects the proton pumps, as important in the evolution of Pacific salmon. Lastly, the lineage to Chinook experienced rapid evolution at the piston arm.

Ocular pulsation correlates with ocular tension: the choroid as piston for an aqueous pump?

Science.gov (United States)

Phillips, C I; Tsukahara, S; Hosaka, O; Adams, W

1992-01-01

In 26 random out-patients, including 13 treated glaucoma patients and ocular hypertensives, the higher the ocular tension, the greater the pulse amplitude, by Alcon pneumotonometry, at a statistically significant level. In a single untreated hypertensive, when 2-hourly pneumotonometry was done for 24 h, the correlation was similar and significant. The higher the diastolic blood pressure, the higher the ocular pulsation, also significantly. Pulsation is suggested to be a pump, the choroid being the piston, contributing (1) to an increase in the outflow of aqueous humour and (2) to a homeostatic mechanism contributing to normalization of the intra-ocular pressure, wherein pulsation increases or decreases, as the intraocular pressure increases or decreases, respectively.

76 FR 54373 - Airworthiness Directives; Austro Engine GmbH Model E4 Diesel Piston Engines

Science.gov (United States)

2011-09-01

... diesel piston engines, with high-pressure (HP) fuel pump, part number (P/N) E4A- 30-100-000, installed... Airworthiness Directives; Austro Engine GmbH Model E4 Diesel Piston Engines AGENCY: Federal Aviation... pressure supply for excessive oscillations to determine if high-pressure (HP) fuel pumps have been exposed...

A linear motor and compact cylinder-piston driver for left ventricular bypass.

Science.gov (United States)

Qian, K X

1990-01-01

A simple, portable, reliable and noise-free pneumatic driver has been developed. It consists of a linear motor attached to a cylinder piston, in one unit. The motor coil is directly wound on the cylinder, and the permanent magnet is fixed to the piston. As a continuous voltage square wave is applied to the coil, the cylinder reciprocates on the piston periodically, producing air pressure and vacuum alternately. In conjunction with a locally made diaphragm pump, the driver was tested in vitro and in vivo. Results demonstrated that the device could drive the diaphragm pump and so support the circulation of an experimental animal. The driver weighs 12 kg. For 200 mmHg air pressure and -80 mmHg vacuum the power consumed is 30 W. Its noise is about 30 dB, less than that of an artificial valve and pump.

The sperm pump of the hangingfly Bittacus planus Cheng (Mecoptera: Bittacidae).

Science.gov (United States)

Gao, Qiong-Hua; Hua, Bao-Zhen

2015-11-01

The males of antliophoran insects usually use a sperm pump to transfer liquid sperm into the reproductive tract of the female. However, the fine structure of the sperm pump and its ejaculatory mechanism has not been thoroughly clarified in many groups of Mecoptera. In this paper, the structure of the sperm pump was investigated in the hangingfly Bittacus planus Cheng, 1949 using light and scanning electron microscopy. The sperm pump mainly consists of a piston fused with a piston-carrying sclerite, a pumping chamber enclosed by the genital folds, which comprises the posterior region of the ejaculatory sac, an ostial sclerite, a phallobase, and other associated structures and muscles. The piston crown plays a major role in the piston movement. The ostial sclerite serves as a discharge valve and is controlled by two antagonistic muscles. No depressor muscles were found attached to the piston. The sperm pumping activity is mainly controlled by the combination of the levator of the piston and the retractor and protractor of the ostial sclerite. The ejaculatory mechanism and phylogenetic significance are briefly discussed based on the structure of the sperm pump. Copyright © 2015 Elsevier Ltd. All rights reserved.

Optimizing the longitudinal and transverse electroosmotic pumping in a rectangular channel with horizontal baffle plates

Science.gov (United States)

Lai, Anison K. R.; Chang, Chien-Cheng; Wang, Chang-Yi

2018-04-01

This paper presents a continued study to our previous work on electroosmotic (EO) flow in a channel with vertical baffle plates by further investigating EO flow through an array of baffle plates arranged in parallel to the channel walls. The flow may be driven either in the direction along or in the direction transverse to the plates, thus distinguishing the longitudinal EO pumping (LEOP) and the transverse EO pumping (TEOP). In both types of EO pumping, it is more interesting to examine the cases when the baffle plates develop a higher zeta potential (denoted by α) than that on the channel walls (β). This semi-analytical study enables us to compare between LEOP and TEOP in the pumping efficiency under similar conditions. The TEOP case is more difficult to solve due to the higher order governing partial differential equations caused by the induced non-uniform pressure gradient distribution. In particular, we examine how the EO pumping rates deviate from those predicted by the Helmholtz-Smoluchowski velocity and illustrate the general trend of optimizing the EO pumping rates with respect to the physical and geometric parameters involved.

Impact of the thermal effect on the load-carrying capacity of a slipper pair for an aviation axial-piston pump

Directory of Open Access Journals (Sweden)

Hesheng TANG

2018-02-01

Full Text Available A thermal hydraulic model based on the lumped parameter method is presented to analyze the load-carrying capacity of a slipper pair in an aviation axial-piston pump under specified operating conditions. Both theoretical and experimental results are presented to demonstrate the validity of the thermal hydraulic model. The results illustrate that the squeezing force and thermal wedge bearing force are the main factors that affect the film thickness and load-carrying capacity. At high oil temperature and high load pressure, the film thickness decreases with increasing clamping force due to a combined action of the squeezing bearing force and the thermal wedge bearing force, but the load-carrying capacity will increase. An increase of the film thickness is proven to be beneficial under high shaft rotational speed but especially dangerous as it strongly increases the ripple amplitude of the film thickness, which leads to decreasing the load-carrying capacity. The structural parameters of the slipper can be optimized to achieve desired performance, such as the slipper radius ratio and orifice length diameter ratio. To satisfy the requirement of the load-carrying capacity, the slipper radius ratio should be selected from 1.4 to 1.8, and the orifice length diameter ratio should be selected from 4 to 5. Keywords: Aviation axial piston pump, Fluid lubrication, Load-carrying capacity, Slipper pair, Thermal effect

回热型双活塞太阳能水泵的设计与研究%Design and Research of Regenerative Double Piston Solar Water Pump

Institute of Scientific and Technical Information of China (English)

崔丹丹; 郑宏飞; 毛巨正; 伍纲

2017-01-01

设计制作了一种利用太阳能或其他余热驱动的回热型双活塞水泵.通过对其建立数学模型,对其循环过程进行理论分析并给出了泵水效率.在理论分析的基础上,搭建实验系统,对其进行了性能测试,得到活塞内部工质的温度和压力变化规律以及泵水速率随加热温度和泵水高度的变化情况.由于本系统采用了双活塞并回收了部分余热,可连续泵水,95℃加热条件下,系统的泵水速率为265 kg/h.结果显示,实验与理论结果有相同的变化趋势,提高加热温度可提升装置的泵水速率和缩短循环时间,有利于提高系统的效率;提高泵水高度将会使泵水速率降低.因此该类型的小型太阳能泵水装置,泵水高度不宜设置过高.%A regenerative double piston pump driven by solar energy or other waste heat is designed and manufactured.Through the mathematical model,the circulation process is analyzed theoretically and the pump water efficiency is given.On the basis of theoretical analysis,the experimental system is built and the performance of the system is tested.The temperature and pressure variation law of the working fluid inside the piston and the variation of pump water rate with the different heating temperatures and pump water heights are obtained.As the system uses double piston and recovered some residual heat,it can continuously pump water and pump water rate of the experimental system reached 265 kg/h at 95℃ heating temperature.The results show that the experimental results agree with the theoretical results.Increasing the heating temperature can improve the pump water rate and shorten the cycle time,which is beneficial to improve the efficiency of the whole system.Meanwhile,increasing pump water height will reduce pump water rate.Therefore,for the type of small solar pump water device,pump water height should not be set too high.

Reduced energy and volume air pump for a seat cushion

Energy Technology Data Exchange (ETDEWEB)

Vaughn, M.R.; Constantineau, E.J.; Groves, G.E.

1997-08-19

An efficient pump system is described for transferring air between sets of bladders in a cushion. The pump system utilizes a reversible piston within a cylinder in conjunction with an equalizing valve in the piston which opens when the piston reaches the end of travel in one direction. The weight of a seated user then forces air back across the piston from an inflated bladder to the previously deflated bladder until the pressure is equalized. In this fashion the work done by the pump is cut in half. The inflation and deflation of the different bladders is controlled to vary the pressure on the several pressure points of a seated user. A principal application is for wheel chair use to prevent pressure ulcers. 12 figs.

Reduced energy and volume air pump for a seat cushion

Energy Technology Data Exchange (ETDEWEB)

Vaughn, Mark R. (Albuquerque, NM); Constantineau, Edward J. (Albuquerque, NM); Groves, Gordon E. (Tijeras, NM)

1997-01-01

An efficient pump system for transferring air between sets of bladders in a cushion. The pump system utilizes a reversible piston within a cylinder in conjunction with an equalizing valve in the piston which opens when the piston reaches the end of travel in one direction. The weight of a seated user then forces air back across the piston from an inflated bladder to the previously deflated bladder until the pressure is equalized. In this fashion the work done by the pump is cut in half. The inflation and deflation of the different bladders is controlled to vary the pressure on the several pressure points of a seated user. A principal application is for wheel chair use to prevent pressure ulcers.

Free-piston Stirling engine system considerations for various space power applications

International Nuclear Information System (INIS)

Dochat, G.R.; Dhar, M.

1991-01-01

The U.S. Government is evaluating power requirements for future space applications. As power requirements increase solar or nuclear dynamic systems become increasingly attractive. Free-Piston Stirling Engines (FPSE) have the potential to provide high reliability, long life, and efficient operation. Therefore, they are excellent candidates for the dynamic power conversion module of a space-based, power-generating system. FPSE can be coupled with many potential heat sources (radioisotope, solar, or nuclear reactor), various heat input systems (pumped loop, heat pipe), heat rejection (pumped loop or heat pipe), and various power management and distribution systems (AC, DC, high or low voltage, and fixed or variable load). This paper will review potential space missions that can be met using free-piston Stirling engines and discusses options of various system integration approaches. Currently free-piston Stirling engine technology for space power applications is being developed under contract with NASA-Lewis Research Center. This paper will also briefly outline the program and recent progress

Fluidic pumping system

International Nuclear Information System (INIS)

Wilson, P.D.

1995-01-01

A fluidic pumping system comprises two charge vessels which communicate with a liquid inlet and a liquid outlet through a fluidic bridge rectifier. A pressurising and depressurising arrangement for alternately pressurising and depressurising the charge vessels comprises a chamber containing a piston and being in communication with the charge vessels. Drive means not mechanically connected to the piston are provided for causing reciprocatory movement of the piston. Movement of the piston in one direction causes pressurisation of one charge vessel to discharge a liquid therefrom through the liquid outlet. Simultaneously, the other charge vessel is depressurised to draw liquid from the liquid inlet into the depressurised charge vessel. Preferably, the drive means for the piston comprises an external solenoid winding at each end of a horizontally arranged chamber. Alternatively, the chamber may be vertically disposed with an external solenoid winding at the upper end of the chamber to effect upward movement of the piston, the piston then falling under gravity upon de-energisation of the winding. (UK)

Free-piston Stirling Engine system considerations for various space power applications

Science.gov (United States)

Dochat, George R.; Dhar, Manmohan

1991-01-01

Free-Piston Stirling Engines (FPSE) have the potential to provide high reliability, long life, and efficient operation. Therefore, they are excellent candidates for the dynamic power conversion module of a space-based, power-generating system. FPSE can be coupled with many potential heat sources (radioisotope, solar, or nuclear reactor), various heat input systems (pumped loop, heat pipe), heat rejection (pumped loop or heat pipe), and various power management and distribution systems (ac, dc, high or low voltage, and fixed or variable load). This paper reviews potential space missions that can be met using free-piston Stirling engines and discusses options of various system integration approaches. This paper briefly outlines the program and recent progress.

Nano-electro-mechanical pump: Giant pumping of water in carbon nanotubes

Science.gov (United States)

Farimani, Amir Barati; Heiranian, Mohammad; Aluru, Narayana R.

2016-05-01

A fully controllable nano-electro-mechanical device that can pump fluids at nanoscale is proposed. Using molecular dynamics simulations, we show that an applied electric field to an ion@C60 inside a water-filled carbon nanotube can pump water with excellent efficiency. The key physical mechanism governing the fluid pumping is the conversion of electrical energy into hydrodynamic flow with efficiencies as high as 64%. Our results show that water can be compressed up to 7% higher than its bulk value by applying electric fields. High flux of water (up to 13,000 molecules/ns) is obtained by the electro-mechanical, piston-cylinder-like moving mechanism of the ion@C60 in the CNT. This large flux results from the piston-like mechanism, compressibility of water (increase in density of water due to molecular ordering), orienting dipole along the electric field and efficient electrical to mechanical energy conversion. Our findings can pave the way towards efficient energy conversion, pumping of fluids at nanoscale, and drug delivery.

21 CFR 880.5725 - Infusion pump.

Science.gov (United States)

2010-04-01

... Infusion pump. (a) Identification. An infusion pump is a device used in a health care facility to pump fluids into a patient in a controlled manner. The device may use a piston pump, a roller pump, or a... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Infusion pump. 880.5725 Section 880.5725 Food and...

Human Aorta Is a Passive Pump

Science.gov (United States)

Pahlevan, Niema; Gharib, Morteza

2012-11-01

Impedance pump is a simple valveless pumping mechanism that operates based on the principles of wave propagation and reflection. It has been shown in a zebrafish that a similar mechanism is responsible for the pumping action in the embryonic heart during early stages before valve formation. Recent studies suggest that the cardiovascular system is designed to take advantage of wave propagation and reflection phenomena in the arterial network. Our aim in this study was to examine if the human aorta is a passive pump working like an impedance pump. A hydraulic model with different compliant models of artificial aorta was used for series of in-vitro experiments. The hydraulic model includes a piston pump that generates the waves. Our result indicates that wave propagation and reflection can create pumping mechanism in a compliant aorta. Similar to an impedance pump, the net flow and the flow direction depends on the frequency of the waves, compliance of the aorta, and the piston stroke.

Variable Displacement Control of the Concrete Pumping System Based on Dynamic Programming

Directory of Open Access Journals (Sweden)

Ye Min

2017-01-01

Full Text Available To solve the problems of cylinder piston striking cylinder and the hydraulic shocking of the main pump, and causing energy waste problem, the method of variable displacement control of piston stroke was proposed. In order to achieve effective control of the piston stroke, variable displacement control model was established under the physical constraint condition of non-collision between piston and cylinder. And the control process was realized by Dynamic Programming(DP, the simulation and test results show that piston of concrete pumping system don’t strike cylinder and reduce the hydraulic shock of the main pump outlet, meanwhile improve the response speed of the cylinder and achieve energy-saving purposes under varying loads. This control model built in the integration design space of structure variable and control variable is of guiding significance for solving open-loop system’s engineering problems.

Two thousand wind pumps in the arid region of Brazil

International Nuclear Information System (INIS)

Feitosa, E.A.N.; Sampaio, G.M.P.

1991-01-01

The North-East part of Brazil is an arid region where water pumping is of vital importance. The main strategy of the Wind Energy Group (Eolica) at the University of Pernambuco is to act as a 'catalyst' between the Brazilian government and the companies involved in wind energy. The company CONESP is a drilling company that is also responsible for choosing the appropriate pumping system and providing maintenance. CONESP already has drilled about 6,000 wells and installed 2,000 conventional windmills with piston pumps. Most of the wells have a very low capacity; thus wind pumps, having a relatively low water pumping capacity, are a suitable solution. However, one of the problems with the installed conventional wind pumps is that the drilled tube wells are not perfectly vertical, resulting in wear of the pump rod. Besides, the maintenance or replacement of the piston pump is time consuming and consequently costly. To reduce operation and maintenance costs, windmills coupled to pneumatic pumps have been developed. Examples are given of air-lift pumps and barc pumps, both using commercially available compressors. The main advantage is that there are no moving parts situated below ground level. Moreover, the windmill does not necessarily have to be placed above the well. Well and windmill can be situated up to 100 metres from each other. The starting torque of this system is also lower than the conventional wind pump. It is concluded that windmills with pneumatic pumps have a relatively low efficiency and higher investment costs compared with windmills coupled to piston pumps. However, CONESP's effort is to optimize the total performance of the pumping system. Due to the lower maintenance costs, pneumatic pumps seem to be a viable alternative to piston pumps. 7 figs., 3 refs

Experiments on the WavePiston, Wave Energy Converter

DEFF Research Database (Denmark)

Angelelli, E.; Zanuttigh, B.; Kofoed, Jens Peter

2011-01-01

This paper analyses the performance of a new Wave Energy Converter (WEC) of the Oscillating Water Column type (OWC), named WavePiston. This near-shore floating device is composed of plates (i.e. energy collectors) sliding around a cylinder, that is placed perpendicular to the shore. Tests...... in the wave basin at Aalborg University allowed to investigate power production in the North Sea typical wave climate, with varying design parameters such as plate dimensions and their mutual distance. The power produced per meter by each collector is about the 5% of the available wave power. Experimental...... results and survivability considerations suggest that the WavePiston would be particularly suited for installations in milder seas. An example application is therefore presented in the Mediterranean Sea, off-shore the island of Sicily. In this case, each collector harvests the 10% of the available wave...

CFD Analysis of an Axial Piston Pump

OpenAIRE

Kumar, Sushil

2010-01-01

Premi extraordinari doctorat curs 2009-2010, àmbit d’Enginyeria Industrial En el ámbito de la Oleohidráulica, las bombas de pistón poseen los diseños más sofisticados, de hecho, las bombas de pistones son las únicos capaces de trabajar a altas presiones, además de poseer el mejor rendimiento de todo el grupo de bombas existentes. Sin embargo, cabe señalar que todos los diseños de las bombas de pistón, se basan principalmente en la experiencia de los diseñadores, por lo tanto no existen her...

Device for covering a string of pump-compressor pipes

Energy Technology Data Exchange (ETDEWEB)

Sharafutdinov, I.G.; Prokopov, O.I.; Rastorgyev, M.A.

1982-01-01

The invention refers to oil field equipment, and more specifically to devices for automatic coverage of the flow of gusher oil and gas wells during the development of a fire near the well. A device is described for covering the string of pump-compressor pipes which includes a housing with piston connected to the string of pump-compressor pipes, shoe, seat and assembly for fixing the piston in the upper position with heat-sensitive substance. It is distinguished by the fact that in order to improve reliability of its triggering when a fire develops, the assembly for fixing the piston is equipped with hydraulic cylinders whose rods are connected to the piston, and the heat sensitive substance is placed in the vessels whose cavities are connected to the above-piston cavities of the hydraulic cylinders and are connected by a common collector.

Some design features of CO2 swing piston expander

International Nuclear Information System (INIS)

Guan Haiqing; Ma Yitai; Li Minxia

2006-01-01

CO 2 is a potential substitute for synthesized refrigerants with favorable environmental properties. To improve the coefficient of performance (COP) of CO 2 heat pump systems, a swing piston expander prototype has been developed for replacing the throttling valve based on the thermodynamic analysis of the operating conditions of a CO 2 transcritical cycle. The measures on reducing the loss of friction and leakage are paramount important to improve the efficiency of the expander. The performance of the CO 2 swing expander prototype was actually tested in a CO 2 transcritical cycle water-to-water heat pump test rig, and the test results illustrate that the isentropic efficiency of the prototype can be more than 28% when running steadily and up to a maximum of about 44%. Some operating characteristics of the swing piston expander are presented according to the analysis of the test results

Modelling the heart with the atrioventricular plane as a piston unit.

Science.gov (United States)

Maksuti, Elira; Bjällmark, Anna; Broomé, Michael

2015-01-01

Medical imaging and clinical studies have proven that the heart pumps by means of minor outer volume changes and back-and-forth longitudinal movements in the atrioventricular (AV) region. The magnitude of AV-plane displacement has also shown to be a reliable index for diagnosis of heart failure. Despite this, AV-plane displacement is usually omitted from cardiovascular modelling. We present a lumped-parameter cardiac model in which the heart is described as a displacement pump with the AV plane functioning as a piston unit (AV piston). This unit is constructed of different upper and lower areas analogous with the difference in the atrial and ventricular cross-sections. The model output reproduces normal physiology, with a left ventricular pressure in the range of 8-130 mmHg, an atrial pressure of approximatly 9 mmHg, and an arterial pressure change between 75 mmHg and 130 mmHg. In addition, the model reproduces the direction of the main systolic and diastolic movements of the AV piston with realistic velocity magnitude (∼10 cm/s). Moreover, changes in the simulated systolic ventricular-contraction force influence diastolic filling, emphasizing the coupling between cardiac systolic and diastolic functions. The agreement between the simulation and normal physiology highlights the importance of myocardial longitudinal movements and of atrioventricular interactions in cardiac pumping. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Thermodynamic and energy saving benefits of hydraulic free-piston engines

International Nuclear Information System (INIS)

Zhao, Zhenfeng; Wang, Shan; Zhang, Shuanlu; Zhang, Fujun

2016-01-01

The hydraulic free-piston engine integrates the internal combustion engine with a hydraulic pump. The piston of an HFPE is not connected to the crankshaft and the piston movement is determined by the forces that act upon it. These features optimize combustion and make higher power density and efficiency increase. In this paper, a detailed thermodynamic and energy saving analysis is performed to demonstrate the fundamental efficiency advantage of an HFPE. The thermodynamic results show that the combustion process can be optimized to an ideal engine cycle. The experimental results show that the HFPE combustion process is a nearly constant-volume process; the efficiency is approximately 50%; the piston displacement and velocity curves for a cycle are the same at any frequency, even at a 1.25 Hz. The maximum velocities are of the same value at high or low frequencies. Similarly, pump output flow is not influenced by frequency. The independent cyclic characteristics of HFPE determine that it should work in higher frequencies when the vehicle runs in Japanese 10–15 road conditions. It indicates that a higher working frequency will lead to the starting frequency of HFPE, and a lower frequency will decrease the pressurized pressure of the hydraulic accumulator. - Highlights: • The thermodynamic and energy saving benefits of the HFPEs was investigated. • The approach of combustion optimization was obtained by adjusting the injection timing and compression ratio. • The high efficiency area of HFPE was given as a function of injection timing and compression pressure. • The maximum efficiency of HFPE of 50% was obtained from the prototype. • The method of energy saving with adjusting the piston frequency was examined.

40 CFR 65.116 - Quality improvement program for pumps.

Science.gov (United States)

2010-07-01

... (for example, piston, horizontal or vertical centrifugal, gear, bellows); pump manufacturer; seal type and manufacturer; pump design (for example, external shaft, flanged body); materials of construction... program. (4) Pump or pump seal inspection. The owner or operator shall inspect all pumps or pump seals...

Open Loop Heat Pipe Radiator Having a Free-Piston for Wiping Condensed Working Fluid

Science.gov (United States)

Weinstein, Leonard M. (Inventor)

2015-01-01

An open loop heat pipe radiator comprises a radiator tube and a free-piston. The radiator tube has a first end, a second end, and a tube wall, and the tube wall has an inner surface and an outer surface. The free-piston is enclosed within the radiator tube and is capable of movement within the radiator tube between the first and second ends. The free-piston defines a first space between the free-piston, the first end, and the tube wall, and further defines a second space between the free-piston, the second end, and the tube wall. A gaseous-state working fluid, which was evaporated to remove waste heat, alternately enters the first and second spaces, and the free-piston wipes condensed working fluid from the inner surface of the tube wall as the free-piston alternately moves between the first and second ends. The condensed working fluid is then pumped back to the heat source.

Double bowl piston

Science.gov (United States)

Meffert, Darrel Henry; Urven, Jr., Roger Leroy; Brown, Cory Andrew; Runge, Mark Harold

2007-03-06

A piston for an internal combustion engine is disclosed. The piston has a piston crown with a face having an interior annular edge. The piston also has first piston bowl recessed within the face of the piston crown. The first piston bowl has a bottom surface and an outer wall. A line extending from the interior annular edge of the face and tangent with the outer wall forms an interior angle greater than 90 degrees with the face of the piston. The piston also has a second piston bowl that is centrally located and has an upper edge located below a face of the piston crown.

Free-Piston Stirling Power Conversion Unit for Fission Surface Power, Phase I Final Report

Science.gov (United States)

Wood, J. Gary; Buffalino, Andrew; Holliday, Ezekiel; Penswick, Barry; Gedeon, David

2010-01-01

This report summarizes the design of a 12 kW dual opposed free-piston Stirling convertor and controller for potential future use in space missions. The convertor is heated via a pumped NaK loop and cooling is provided by a pumped water circuit. Convertor efficiency is projected at 27 percent (AC electrical out/heat in). The controller converts the AC electrical output to 120 Vdc and is projected at 91 percent efficiency. A mechanically simple arrangement, based on proven technology, was selected in which the piston is resonated almost entirely by the working space pressure swing, while the displacer is resonated by planar mechanical springs in the bounce space.

Limitation of Piston Centre Shift in Free Piston Stirling Engines

Energy Technology Data Exchange (ETDEWEB)

Van der Woude, R.R. [ECN Energy in the Built Environment and Networks, Petten (Netherlands)

2006-09-15

Piston centre shift is one of the phenomena setting Free Piston engines apart from traditional kinematic engines. In kinematic engines the piston centre position is determined by the design of the engine's internal mechanisms. In Free Piston engines however, the piston's mid-stroke position is determined by the balance of forces acting on the piston, in particular flexure and gas pressure forces. As a result, a mean pressure difference across the piston emerging during engine operation will cause the piston mid-stroke position to shift away from the geometrical centre. This process will continue until a new balance is reached with the flexure forces counteracting the new mean pressure balance. Yet, before the new equilibrium is reached, the resulting piston centre shift may have grown to such an extent that piston overstrokes have become inevitable. In order to limit piston centre shift and prevent piston overstrokes, several solutions have been proposed in the past. Popular solutions include ingenious mechanisms to vent gas between the spaces separated by the piston, in an attempt to limit the pressure difference. Enatec however has adopted a different approach by applying a precisely determined clearance between the piston and cylinder. With the right shape the clearance effectively limits the mean pressure difference across the piston and therefore limits the extent of the piston centre drift. Taking benefit of tightly controlled tolerances of both piston and cylinder, Enatec has demonstrated the effectiveness of this simple concept in series produced engines.

Experimental Study on the WavePiston Wave Energy Converter

DEFF Research Database (Denmark)

Pecher, Arthur; Kofoed, Jens Peter; Angelelli, E.

This report presents the results of an experimental study of the power performance of the WavePiston wave energy converter. It focuses mainly on evaluating the power generating capabilities of the device and the effect of the following issues: Scaling ratios PTO loading Wave height and wave period...... dependency Oblique incoming waves Distance between plates During the study, the model supplied by the client, WavePiston, has been rigorously tested as all the anticipated tests have been done thoroughly and during all tests, good quality data has been obtained from all the sensors....

76 FR 33660 - Airworthiness Directives; Austro Engine GmbH Model E4 Diesel Piston Engines

Science.gov (United States)

2011-06-09

... Model E4 Diesel Piston Engines AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of... pressure supply for excessive oscillations to determine if high-pressure fuel pumps have been exposed to damaging pressure oscillations. Pumps that have been exposed require replacement before further flight...

Special compressor technology for a new generation of heat pumps for domestic applications. Free piston technology with zero-oil torsion drive; Speciale compressortechnologie voor een nieuwe generatie warmtepompen voor huishoudelijke toepassingen. Vrijezuigertechnologie met olieloze torsie-aandrijving

Energy Technology Data Exchange (ETDEWEB)

Wissink, E.B. [TNO, Apeldoorn (Netherlands)

2013-02-15

To meet the increasing demand for small high efficient domestic heat pumps with a good total cost of ownership performance, a next generation of heat pumps is required. This article is dealing with the development of a new compressor technology for domestic heat pumps. After identification of the main losses in mechanical driven low capacity heat pump cycles, it became clear that a concept with a (semi-)free piston compressor has the potency to improve the efficiency significantly. An evaluation showed that none of the existing free-piston designs meets essential requirements like low internal friction, small size integrated electromotor and hermetic design suitable for all refrigerants, including ammonia. Therefore TNO designed a complete new free piston compressor making use of the following two design philosophies: balancing mechanical forces by using symmetry and reducing motor size by use of transmission ratio based on elastic deformation and the peak shaving effect of the energy contents (kinetic and elastic) of the compressor running in a natural frequency mode. This paper describes the background, the design steps and the final design of the new torsion compressor technology [Dutch] Om aan de toenemende vraag naar kleine hoog-efficiente warmtepompen voor woningverwarming met een lage exploitatiekostprijs te voldoen, is een nieuwe generatie warmtepompen vereist. Dit artikel beschrijft de ontwikkeling van een nieuwe compressortechnologie voor huishoudelijke warmtepompen. Na het onderzoeken van de belangrijkste verliezen in mechanisch aangedreven warmtepompsystemen met een klein verwarmingsvermogen werd duidelijk dat een concept met een (semi-)vrijezuigercompressor de potentie heeft om de efficientie aanzienlijk te verbeteren.

A novel small dynamic solar thermal desalination plant with a fluid piston converter

International Nuclear Information System (INIS)

Mahkamov, Khamid; Orda, Eugene; Belgasim, Basim; Makhkamova, Irina

2015-01-01

Highlights: • A dynamic solar desalination plant was developed which works cyclically. • It integrates an evacuated tube solar collector and fluid piston converter. • Pressure during desalination process varies with frequency of 2–4 Hz. • The system has a small increase in fresh water yield and provides pumping capacity. • Mathematical modelling provides accurate description of experimental performance. - Abstract: An innovative small dynamic water desalination plant was developed and tested under laboratory conditions. The system is a combination of a heat pipe evacuated tube solar collector, conventional condenser and novel fluid piston converter. Saline water is boiled and turned into vapour in the manifold of the solar collector. A small fraction of the solar energy supplied to the plant is used to drive the fluid piston converter. Oscillations of the fluid piston periodically change the volume and pressure in the plant. For the duration of approximately half of the periodic cycle the pressure in the plant drops below the atmospheric level causing flash boiling of saline water in the manifold of the solar collector. Generated vapour is turned into fresh water in the condenser which is surrounded by a cooling jacket with saline water. The flash boiling effect improves the fresh water production capacity of the plant. Additionally, the fluid piston converter drives a pump which provides lifting of saline water from a well and pumps this through the cooling jacket of the condenser to a saline water storage tank. This tank replenishes saline water in the manifold of the solar collector. Experimental investigations demonstrated the saline water self-circulation capability of the plant and increase in the fresh water production compared to the static mode of operation. Experimental data was also used to calibrate the mathematical model of the plant. Comparison of theoretical and experimental information demonstrates that the model accurately predicts the

Pistonics

DEFF Research Database (Denmark)

Perram, John W.; Præstgaard, Eigil; Smith, Edgar R.

2011-01-01

is proportional to its internal energy. We report molecular dynamics experiments with ideal gas particles and show that they can exchange energy with their container. We then construct a dynamical system modelling the motion of the piston and heat transfer to the surroundings when the piston is released...... to the dynamical system can make it resemble a quasi-static process. We then generalise the dynamical system to a two-compartment adiabatic cylinder in which the gases in the two chambers are separated by a movable piston. We show that, if the piston is subjected to infinitesimal kinetic friction, in all cases...

Investigation of preparation technique and tribological properties of CrN piston rings coatings

International Nuclear Information System (INIS)

Cai Zhihai; Zhang Ping; Zhao Junjun; Du Jun; Niu Qingyin

2009-01-01

By using multi-ion plating, CrN films were made on surface of piston rings to improve its tribological properties and service life. Effects of nitrogen content to prepare the film on hardness and phase structure were studied. The high-temperature tribological properties of Cr plating and CrN films were compared with CETR friction tester. The results show that nitrogen partial pressure significantly affects the mechanical properties of CrN films. With increasing N 2 partial pressure, preferential growth orientation of the film changed from Cr 2 N(211) to CrN(220) phase, leading to two hardness peaks corresponding to the Cr 2 N and CrN phases,respectively. Having higher high-temperature wear resistance and lower friction coefficient than Cr plating, the CrN films are suitable for piston rings under high temperature conditions. (authors)

Operating experience with a high capacity helium pump under supercritical conditions

International Nuclear Information System (INIS)

Lehmann, W.; Minges, J.

1984-01-01

This chapter discusses the development and testing of a high-capacity piston pump to provide forced cooling for large superconducting magnets. The pump is a three cylinder, vertically arranged single-acting piston pump equipped with a frequency controlled three-phase geared motor operating at room temperature. The pump is capable of delivering up to 150 g/s at a maximum speed of 310 rpm and under the inlet conditions of 4 bar/4.5 K. No decline was noticed in delivery head and efficiencies during more than 560 hours of operation. It is concluded that the pump satisfies all requirements for circulating large mass flows across great pressure differences as needed (e.g. in fusion magnet design)

75 FR 68179 - Airworthiness Directives; Austro Engine GmbH Model E4 Diesel Piston Engines

Science.gov (United States)

2010-11-05

... Airworthiness Directives; Austro Engine GmbH Model E4 Diesel Piston Engines AGENCY: Federal Aviation... pumps failed as a result of pressure oscillations in the fuel supply line. We are issuing this AD to.... Analyses have shown that high pressure (HP) fuel pumps failed as a result of pressure oscillations in the...

A micro surface tension pump (MISPU) in a glass microchip.

Science.gov (United States)

Peng, Xing Yue Larry

2011-01-07

A non-membrane micro surface tension pump (MISPU) was fabricated on a glass microchip by one-step glass etching. It needs no material other than glass and is driven by digital gas pressure. The MISPU can be seen working like a piston pump inside the glass microchip under a microscope. The design of the valves (MISVA) and pistons (MISTON) was based on the surface tension theory of the micro surface tension alveolus (MISTA). The digital gas pressure controls the moving gas-liquid interface to open or close the input and output MISVAs to refill or drive the MISTON for pumping a liquid. Without any moving parts, a MISPU is a kind of long-lasting micro pump for micro chips that does not lose its water pumping efficiency over a 20-day period. The volumetric pump output varied from 0 to 10 nl s(-1) when the pump cycle time decreased from 5 min to 15 s. The pump head pressure was 1 kPa.

Development and verification of a reciprocating test rig designed for investigation of piston ring tribology

DEFF Research Database (Denmark)

Pedersen, Michael Torben; Imran, Tajammal; Klit, Peder

2009-01-01

This paper describes the development and verification of a reciprocating test rig, which was designed to study the piston ring tribology. A crank mechanism is used to generate a reciprocating motion for a moving plate, which acts as the liner. A stationary block acting as the ring package is loaded......, which is suitable for the study of piston ring tribology....

40 CFR 63.1035 - Quality improvement program for pumps.

Science.gov (United States)

2010-07-01

...., piston, horizontal or vertical centrifugal, gear, bellows); pump manufacturer; seal type and manufacturer... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Quality improvement program for pumps... improvement program for pumps. (a) Criteria. If, on a 6-month rolling average, at least the greater of either...

An investigation of the fluid-structure interaction of piston/cylinder interface

Science.gov (United States)

Pelosi, Matteo

The piston/cylinder lubricating interface represents one of the most critical design elements of axial piston machines. Being a pure hydrodynamic bearing, the piston/cylinder interface fulfills simultaneously a bearing and sealing function under oscillating load conditions. Operating in an elastohydrodynamic lubrication regime, it also represents one of the main sources of power loss due to viscous friction and leakage flow. An accurate prediction of the time changing tribological interface characteristics in terms of fluid film thickness, dynamic pressure field, load carrying ability and energy dissipation is necessary to create more efficient interface designs. The aim of this work is to deepen the understanding of the main physical phenomena defining the piston/cylinder fluid film and to discover the impact of surface elastic deformations and heat transfer on the interface behavior. For this purpose, a unique fully coupled multi-body dynamics model has been developed to capture the complex fluid-structure interaction phenomena affecting the non-isothermal fluid film conditions. The model considers the squeeze film effect due to the piston micro-motion and the change in fluid film thickness due to the solid boundaries elastic deformations caused by the fluid film pressure and by the thermal strain. The model has been verified comparing the numerical results with measurements taken on special designed test pumps. The fluid film calculated dynamic pressure and temperature fields have been compared. Further validation has been accomplished comparing piston/cylinder axial viscous friction forces with measured data. The model has been used to study the piston/cylinder interface behavior of an existing axial piston unit operating at high load conditions. Numerical results are presented in this thesis.

Performance Analysis of a Thermoelectric Solar Collector Integrated with a Heat Pump

Science.gov (United States)

Lertsatitthanakorn, C.; Jamradloedluk, J.; Rungsiyopas, M.; Therdyothin, A.; Soponronnarit, S.

2013-07-01

A novel heat pump system is proposed. A thermoelectric solar collector was coupled to a solar-assisted heat pump (TESC-HP) to work as an evaporator. The cooling effect of the system's refrigerant allowed the cold side of the system's thermoelectric modules to work at lower temperature, improving the conversion efficiency. The TESC-HP system mainly consisted of transparent glass, an air gap, an absorber plate that acted as a direct expansion-type collector/evaporator, an R-134a piston-type hermetic compressor, a water-cooled plate-type condenser, thermoelectric modules, and a water storage tank. Test results indicated that the TESC-HP has better coefficient of performance (COP) and conversion efficiency than the separate units. For the meteorological conditions in Mahasarakham, the COP of the TESC-HP system can reach 5.48 when the average temperature of 100 L of water is increased from 28°C to 40°C in 60 min with average ambient temperature of 32.5°C and average solar intensity of 815 W/m2, whereas the conversion efficiency of the TE power generator was around 2.03%.

40 CFR 63.176 - Quality improvement program for pumps.

Science.gov (United States)

2010-07-01

... type (e.g., piston, horizontal or vertical centrifugal, gear, bellows); pump manufacturer; seal type... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Quality improvement program for pumps... improvement program for pumps. (a) In Phase III, if, on a 6-month rolling average, the greater of either 10...

GAS METERING PUMP

Science.gov (United States)

George, C.M.

1957-12-31

A liquid piston gas pump is described, capable of pumping minute amounts of gas in accurately measurable quantities. The pump consists of a flanged cylindrical regulating chamber and a mercury filled bellows. Sealed to the ABSTRACTS regulating chamber is a value and having a gas inlet and outlet, the inlet being connected by a helical channel to the bellows. A gravity check valve is in the gas outlet, so the gas passes through the inlet and the helical channel to the bellows where the pumping action as well as the metering is accomplished by the actuation of the mercury filled bellows. The gas then flows through the check valve and outlet to any associated apparatus.

Analysis of the cylinder block tilting inertia moment and its effect on the performance of high-speed electro-hydrostatic actuator pumps of aircraft

Directory of Open Access Journals (Sweden)

Junhui ZHANG

2018-01-01

Full Text Available Electro-hydrostatic actuator (EHA pumps are usually characterized as high speed and small displacement. The tilting inertia moment on the cylinder block produced by the inertia forces of piston/slipper assemblies cannot be ignored when analyzing the cylinder block balance. A large tilting inertia moment will make the cylinder block tilt away from the valve plate, resulting in severe wear and significantly increased leakage. This paper presents an analytical expression for the tilting inertia moment on the cylinder block by means of vector analysis. In addition, a high-speed test rig was built up, and experiments on an EHA pump prototype were carried out at high speeds of up to 10,000 r/min. The predicted nature of the cylinder block tilt at high speeds corresponds closely to the witness marks on the dismantled EHA pump prototype. It is suggested that more attention should be given to the tilting inertia moment acting on the cylinder block of an EHA pump since both wear and leakage flow between the cylinder block and the valve plate are very much dependent on this tilting moment.

Test of a cryogenic helium pump

International Nuclear Information System (INIS)

Lue, J.W.; Miller, J.R.; Walstrom, P.L.; Herz, W.

1981-01-01

The design of a cryogenic helium pump for circulating liquid helium in a magnet and the design of a test loop for measuring the pump performance in terms of mass flow vs pump head at various pump speeds are described. A commercial cryogenic helium pump was tested successfully. Despite flaws in the demountable connections, the piston pump itself has performed satisfactorily. A helium pump of this type is suitable for the use of flowing supercritical helium through Internally Cooled Superconductor (ICS) magnets. It has pumped supercritical helium up to 7.5 atm with a pump head up to 2.8 atm. The maximum mass flow rate obtained was about 16 g/s. Performance of the pump was degraded at lower pumping speeds

Design and Fabrication of a 5-kWe Free-Piston Stirling Power Conversion System

Science.gov (United States)

Chapman, Peter A.; Walter, Thomas J.; Brandhorst, Henry W., Jr.

2008-01-01

Progress in the design and fabrication of a 5-kWe free-piston Stirling power conversion system is described. A scaled-down version of the successful 12.5-kWe Component Test Power Converter (CTPC) developed under NAS3-25463, this single cylinder prototype incorporates cost effective and readily available materials (steel versus beryllium) and components (a commercial linear alternator). The design consists of a displacer suspended on internally pumped gas bearings and a power piston/alternator supported on flexures. Non-contacting clearance seals are used between internal volumes. Heat to and from the prototype is supplied via pumped liquid loops passing through shell and tube heat exchangers. The control system incorporates several novel ideas such as a pulse start capability and a piston stroke set point control strategy that provides the ability to throttle the engine to match the required output power. It also ensures stable response to various disturbances such as electrical load variations while providing useful data regarding the position of both power piston and displacer. All design and analysis activities are complete and fabrication is underway. Prototype test is planned for summer 2008 at Foster-Miller to characterize the dynamics and steady-state operation of the prototype and determine maximum power output and system efficiency. Further tests will then be performed at Auburn University to determine start-up and shutdown characteristics and assess transient response to temperature and load variations.

PISTON

Energy Technology Data Exchange (ETDEWEB)

Sewell, Christopher Meyer [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2014-01-08

This presentation was a part of the guest lecture series for graduate classes at the University of Oregon on many-core visualization. It discussed a practical introduction to high-level data parallelism using thrust and PISTON; presented an overview of PISTON and PINION; provided tutorial examples; additional details on research results.

Flow pumping system for physiological waveforms.

Science.gov (United States)

Tsai, William; Savaş, Omer

2010-02-01

A pulsatile flow pumping system is developed to replicate flow waveforms with reasonable accuracy for experiments simulating physiological blood flows at numerous points in the body. The system divides the task of flow waveform generation between two pumps: a gear pump generates the mean component and a piston pump generates the oscillatory component. The system is driven by two programmable servo controllers. The frequency response of the system is used to characterize its operation. The system has been successfully tested in vascular flow experiments where sinusoidal, carotid, and coronary flow waveforms are replicated.

Pumps for nuclear facilities

International Nuclear Information System (INIS)

1999-01-01

The guide describes how the Finnish Radiation and Nuclear Safety Authority (STUK) controls pumps and their motors at nuclear power plants and other nuclear facilities. The scope of the control is determined by the Safety Class of the pump in question. The various phases of the control are: (1) review of construction plan, (2) control of manufacturing, and construction inspection, (3) commissioning inspection, and (4) control during operation. STUK controls Safety Class 1, 2 and 3 pumps at nuclear facilities as described in this guide. STUK inspects Class EYT (non-nuclear) pumps separately or in connection with the commissioning inspections of the systems. This guide gives the control procedure and related requirements primarily for centrifugal pumps. However, it is also applied to the control of piston pumps and other pump types not mentioned in this guide

New Configurations of Micro Plate-Fin Heat Sink to Reduce Coolant Pumping Power

DEFF Research Database (Denmark)

Kolaei, Alireza Rezania; Rosendahl, Lasse

2012-01-01

the optimum heat sink configuration. The particular focus of this study is to reduce the coolant mass flow rate by considering the thermal resistances of the heat sinks and, thereby, to reduce the coolant pumping power in the system. The threedimensional governing equations for the fluid flow and the heat......The thermal resistance of heat exchangers has a strong influence on the electric power produced by a thermoelectric generator (TEG). In this work, a real TEG device is applied to three configurations of micro plate-fin heat sink. The distance between certain microchannels is varied to find...... heat sink configurations reduces the coolant pumping power in the system....

Overview of NASA Lewis Research Center free-piston Stirling engine technology activities applicable to space power systems

Science.gov (United States)

Slaby, Jack G.

1987-01-01

A brief overview is presented of the development and technological activities of the free-piston Stirling engine. The engine started as a small scale fractional horsepower engine which demonstrated basic engine operating principles and the advantages of being hermetically sealed, highly efficient, and simple. It eventually developed into the free piston Stirling engine driven heat pump, and then into the SP-100 Space Reactor Power Program from which came the Space Power Demonstrator Engine (SPDE). The SPDE successfully operated for over 300 hr and delivered 20 kW of PV power to an alternator plunger. The SPDE demonstrated that a dynamic power conversion system can, with proper design, be balanced; and the engine performed well with externally pumped hydrostatic gas bearings.

Tritium evacuataion performance of a large oil-free reciprocating pump

International Nuclear Information System (INIS)

Hayashi, T.; Yamada, M.; Konishi, S.

1994-01-01

In fusion reactors large dry vacuum and transfer pumps are needed for various applications such as backing and roughing for torus evacuation, gas transfer and processing in the fuel cycle, and facility vacuum for safety systems. There are some commercial use oil-free pumps, however, most of all these pumps have low pumping function for hydrogen gases and also at high discharge pressure. A large oil-free reciprocating pump has been developed for high tritium services at the Tritium Process Laboratory (TPL) in the Japan Atomic Energy Research Institute (JAERI). This pump is mainly composed four-stage compression vertical cylinders, a single acting piston with piston rings made by carbon polyimide composite and two buffer tanks. Each stage in the cylinder has 16 special check valves. The process line is isolated completely to crank-case oil by dynamic metal bellows. Design pumping speed is 54 m 3 /hr for hydrogen gas at 5 Torr of discharge pressures. After cold testing in TPL, this pump was shipped and installed in the Tritium Systems Test Assembly (TSTA) loop of the Los Alamos National Laboratory under the US-Japan Collaboration program on fusion technology

ピストンポンプ・モータにおけるピストンの回転運動と摩擦力

OpenAIRE

田中, 嘉津彦; 中原, 綱光; 京極, 啓史

1993-01-01

The influence of the piston rotation on the frictional forces between the piston and the cylinder has been studied experimentally for a swash plate type piston pump and motor. In order to measure the rotational speeds of the piston, the capacitance detecting method has been employed for the piston with the slits. The frictional forces have been measured by means of Piezo-type load washers connected to the floating cylinder. The results show that the piston rotates even under severely lubricat...

Pumps for nuclear industry

International Nuclear Information System (INIS)

Tanguy, L.

1978-01-01

In order to meet the requirements of nuclear industry for the transfer of corrosive, toxic, humidity sensitive or very pure gases, different types of pumps were developped and commercialized. Their main characteristics are to prevent pollution of the transfered fluid by avoiding any contact between this fluid and the lubricated parts of the machine, and to prevent a contamination of the atmosphere or of the fluid by a total tightness. Patellar pumps have been particularly developped because the metallic bellows are quite reliable and resistant in this configuration. Two types are described: patellar pumps without friction and barrel pumps whose pistons are provided with rings sliding in the cylinders without lubrication [fr

DESIGN AND CONSTRUCTION OF A HYDRAULIC PISTON

OpenAIRE

Santos De la Cruz, Eulogio; Rojas Lazo, Oswaldo; Yenque Dedios, Julio; Lavado Soto, Aurelio

2014-01-01

A hydraulic system project includes the design, materials selection and construction of the hydraulic piston, hydraulic circuit and the joint with the pump and its accesories. This equiment will be driven by the force of moving fluid, whose application is in the devices of machines, tools, printing, perforation, packing and others. El proyecto de un sistema hidráulico, comprende el diseño, selección de materiales y construcción del pistón hidráulico, circuito hidráulico y el ensamble con l...

A highly self-adaptive cold plate for the single-phase mechanically pumped fluid loop for spacecraft thermal management

International Nuclear Information System (INIS)

Wang, Ji-Xiang; Li, Yun-Ze; Zhang, Hong-Sheng; Wang, Sheng-Nan; Liang, Yi-Hao; Guo, Wei; Liu, Yang; Tian, Shao-Ping

2016-01-01

Highlights: • A highly self-adaptive cold plate integrated with paraffin-based actuator is proposed. • Higher operating economy is attained due to an energy-efficient strategy. • A greater compatibility of the current space control system is obtained. • Model was entrenched theoretically to design the system efficiently. • A strong self-adaptability of the cold plate is observed experimentally. - Abstract: Aiming to improve the conventional single-phase mechanically pumped fluid loop applied in spacecraft thermal control system, a novel actively-pumped loop using distributed thermal control strategy was proposed. The flow control system for each branch consists primarily of a thermal control valve integrated with a paraffin-based actuator residing in the front part of each corresponding cold plate, where both coolant’s flow rate and the cold plate’s heat removal capability are well controlled sensitively according to the heat loaded upon the cold plate due to a conversion between thermal and mechanical energies. The operating economy enhances remarkably owing to no energy consumption in flow control process. Additionally, realizing the integration of the sensor, controller and actuator systems, it simplifies structure of the traditional mechanically pumped fluid loop as well. Revolving this novel scheme, mathematical model regarding design process of the highly specialized cold plate was entrenched theoretically. A validating system as a prototype was established on the basis of the design method and the scheduled objective of the controlled temperature (43 °C). Then temperature control performances of the highly self-adaptive cold plate under various operating conditions were tested experimentally. During almost all experiments, the controlled temperature remains within a range of ±2 °C around the set-point. Conclusions can be drawn that this self-driven control system is stable with sufficient fast transient responses and sufficient small steady

Efficiency of a variable displacement open circuit floating cup pump

NARCIS (Netherlands)

Vael, G.E.M.; Achten, P.A.J.; Brink, van den T.L.

2009-01-01

The Floating Cup Displacement principle is a relatively new axial piston displacement principle for hydrostatic pumps, motors and transformers. Since its origin in 2001, it has been mainly applied in fixed displacement pump prototypes. At the SICFP’05, a design for a variable displacement open

Conformational change during photocycle of bacteriorhodopsin and its proton-pumping mechanism.

Science.gov (United States)

Chou, K C

1993-06-01

Based on the recent finding on the structural difference of seven helix bundles in the all-trans and 13-cis bacteriorhodopsins, the distances among the key groups performing the function of proton translocation as well as their microenvironments have been investigated. Consequently, a pore-gated model was proposed for the light-driven proton-pumping mechanism of bacteriorhodopsin. According to this model, the five double-bounded polyene chain in retinal chromophore can be phenomenologically likened to a molecular "lever," whose one end links to a "piston" (the beta-ionone ring) and the other end to a pump "relay station" (the Schiff base). During the photocycle of bacteriorhodopsin, the molecular "lever" is moving up and down as marked by the position change of the "piston," so as to trigger the gate of pore to open and close alternately. When the "piston" is up, the pore-controlled gate is open so that the water channel from Asp-96 to the Schiff base and that from the Schiff base to Asp-85 is established; when the "piston" is down, the pore-controlled gate is closed and the water channels for proton transportation in both the cytoplasmic half and extracellular half are blocked. The current model allows a consistent interpretation of a great deal of experimental data and also provides a useful basis for further investigating the mechanism of proton pumping by bacteriorhodopsin.

Magnetic-flux pump

Science.gov (United States)

Hildebrandt, A. F.; Elleman, D. D.; Whitmore, F. C. (Inventor)

1966-01-01

A magnetic flux pump is described for increasing the intensity of a magnetic field by transferring flux from one location to the magnetic field. The device includes a pair of communicating cavities formed in a block of superconducting material, and a piston for displacing the trapped magnetic flux into the secondary cavity producing a field having an intense flux density.

The study of pressure fluctuations in the pressure line of the pump and of the efficiency of the vibration absorbers

Directory of Open Access Journals (Sweden)

O.V. Korolyov

2016-12-01

Full Text Available The article presents the results of experimental studies of pressure fluctuations in the pipes of piston pumps. The relevance of these studies is due to the need to reduce the pressure fluctuations that create a positive displacement pumps, due to their negative impact not only on the reliability of the pump, but the accuracy of flow measurement and pressure of the medium supplied to such pumps. Aim: The aim of this study was to investigate the hydraulic characteristics of pulsating flows in pressure lines piston pumps of liquefied gas, as well as the study of the effectiveness of the dampers of pressure pulsations and conformity of their parameters to the calculation. Materials and Methods: As a drive used the piston pumps − single-line and trilinear. In the tests recorded pressure fluctuations in the pressure line. For this purpose the low-inertia pressure sensors 15.0 MPa working complete with strain test station, which allows registering the pressure fluctuations at frequencies up to 10 kHz. Strain test station output signal fed to the input of the oscilloscope operating in memory mode. In all tests the pressure sensor is mounted at three points - after the piston group on the pressure line before the damping device and after it. In the experiment, three different damper was used - two new, designed by the author's method and one regular damper, which are equipped with serial piston pumps. Dampers installed vertically, the flow entering to the lower cap, and an output through the side surface. Results: The experimental results confirmed the general position of the greater efficiency of complex composite filters and the correctness of chosen method of their calculation, proposed earlier by the authors. In particular, the actual level of weakening of pressure fluctuations on developed damper with a high degree coincided with the calculated results.

Predictive piston motion control in a free-piston internal combustion engine

Energy Technology Data Exchange (ETDEWEB)

Mikalsen, R.; Jones, E.; Roskilly, A.P. [Sir Joseph Swan Institute for Energy Research, Newcastle University, Newcastle upon Tyne, NE1 7RU England (United Kingdom)

2010-05-15

A piston motion controller for a free-piston internal combustion engine is presented. To improve dynamic performance in the control of the piston motion and engine compression ratio, the controller response is determined from a prediction of engine top dead centre error rather than the measured value from the previous cycle. The proposed control approach showed superior performance compared with that of standard PI feedback control known from the literature due to a reduced control action time delay. The manipulation of fuel injection timing to reduce in-cylinder pressure peaks and cycle-to-cycle variations was also studied, indicating that with the piston motion estimation, the injection timing is a powerful control variable for this purpose. (author)

Cooled spool piston compressor

Science.gov (United States)

Morris, Brian G. (Inventor)

1993-01-01

A hydraulically powered gas compressor receives low pressure gas and outputs a high pressure gas. The housing of the compressor defines a cylinder with a center chamber having a cross-sectional area less than the cross-sectional area of a left end chamber and a right end chamber, and a spool-type piston assembly is movable within the cylinder and includes a left end closure, a right end closure, and a center body that are in sealing engagement with the respective cylinder walls as the piston reciprocates. First and second annual compression chambers are provided between the piston enclosures and center housing portion of the compressor, thereby minimizing the spacing between the core gas and a cooled surface of the compressor. Restricted flow passageways are provided in the piston closure members and a path is provided in the central body of the piston assembly, such that hydraulic fluid flows through the piston assembly to cool the piston assembly during its operation. The compressor of the present invention may be easily adapted for a particular application, and is capable of generating high gas pressures while maintaining both the compressed gas and the compressor components within acceptable temperature limits.

Modeling and simulation of flow field in giant magnetostrictive pump

Science.gov (United States)

Zhao, Yapeng; Ren, Shiyong; Lu, Quanguo

2017-09-01

Recent years, there has been significant research in the design and analysis of giant magnetostrictive pump. In this paper, the flow field model of giant magnetostrictive pump was established and the relationship between pressure loss and working frequency of piston was studied by numerical simulation method. Then, the influence of different pump chamber height on pressure loss in giant magnetostrictive pump was studied by means of flow field simulation. Finally, the fluid pressure and velocity vector distribution in giant magnetostrictive pump chamber were simulated.

The Analysis of Secondary Motion and Lubrication Performance of Piston considering the Piston Skirt Profile

Directory of Open Access Journals (Sweden)

Yanjun Lu

2018-01-01

Full Text Available The work performance of piston-cylinder liner system is affected by the lubrication condition and the secondary motion of the piston. Therefore, more and more attention has been paid to the secondary motion and lubrication of the piston. In this paper, the Jakobson-Floberg-Olsson (JFO boundary condition is employed to describe the rupture and reformation of oil film. The average Reynolds equation of skirt lubrication is solved by the finite difference method (FDM. The secondary motion of piston-connecting rod system is modeled; the trajectory of the piston is calculated by the Runge-Kutta method. By considering the inertia of the connecting rod, the influence of the longitudinal and horizontal profiles of piston skirt, the offset of the piston pin, and the thermal deformation on the secondary motion and lubrication performance is investigated. The parabolic longitudinal profile, the smaller top radial reduction and ellipticities of the middle-convex piston, and the bigger bottom radial reduction and ellipticities can effectively reduce the secondary displacement and velocity, the skirt thrust, friction, and the friction power loss. The results show that the connecting rod inertia, piston skirt profile, and thermal deformation have important influence on secondary motion and lubrication performance of the piston.

Integral Ring Carbon-Carbon Piston

Science.gov (United States)

Northam, G. Burton (Inventor)

1999-01-01

An improved structure for a reciprocating internal combustion engine or compressor piston fabricate from carbon-carbon composite materials is disclosed. An integral ring carbon-carbon composite piston, disclosed herein, reduces the need for piston rings and for small clearances by providing a small flexible, integral component around the piston that allows for variation in clearance due to manufacturing tolerances, distortion due to pressure and thermal loads, and variations in thermal expansion differences between the piston and cylinder liner.

Overview of Multi-Kilowatt Free-Piston Stirling Power Conversion Research at GRC

Science.gov (United States)

Geng, Steven M.; Mason, Lee S.; Dyson, Rodger W.; Penswick, L. Barry

2008-01-01

As a step towards development of Stirling power conversion for potential use in Fission Surface Power (FSP) systems, a pair of commercially available 1 kW class free-piston Stirling convertors and a pair of commercially available pressure wave generators (which will be plumbed together to create a high power Stirling linear alternator test rig) have been procured for in-house testing at Glenn Research Center. Delivery of both the Stirling convertors and the linear alternator test rig is expected by October, 2007. The 1 kW class free-piston Stirling convertors will be tested at GRC to map and verify performance. The convertors will later be modified to operate with a NaK liquid metal pumped loop for thermal energy input. The high power linear alternator test rig will be used to map and verify high power Stirling linear alternator performance and to develop power management and distribution (PMAD) methods and techniques. This paper provides an overview of the multi-kilowatt free-piston Stirling power conversion work being performed at GRC.

Overview of Multi-kilowatt Free-Piston Stirling Power Conversion Research at GRC

Science.gov (United States)

Geng, Steven M.; Mason, Lee S.; Dyson, Rodger W.; Penswick, L. Barry

2008-01-01

As a step towards development of Stirling power conversion for potential use in Fission Surface Power (FSP) systems, a pair of commercially available 1 kW class free-piston Stirling convertors and a pair of commercially available pressure wave generators (which will be plumbed together to create a high power Stirling linear alternator test rig) have been procured for in-house testing at Glenn Research Center. Delivery of both the Stirling convertors and the linear alternator test rig is expected by October, 2007. The 1 kW class free-piston Stirling convertors will be tested at GRC to map and verify performance. The convertors will later be modified to operate with a NaK liquid metal pumped loop for thermal energy input. The high power linear alternator test rig will be used to map and verify high power Stirling linear alternator performance and to develop power management and distribution (PMAD) methods and techniques. This paper provides an overview of the multi-kilowatt free-piston Stirling power conversion work being performed at GRC.

Free-piston driver performance characterisation using experimental shock speeds through helium

Science.gov (United States)

Gildfind, D. E.; James, C. M.; Morgan, R. G.

2015-03-01

Tuned free-piston driver operation involves configuring the driver to produce a relatively steady blast of driver gas over the critical time scales of the experiment. For the purposes of flow condition development and parametric studies, it is useful to establish some average working values of the driver pressure and temperature for a given driver operating condition. However, in practise, these averaged values need to produce sufficiently accurate estimates of performance. In this study, two tuned driver conditions in the X2 expansion tube have been used to generate shock waves through a helium test gas. The measured shock speeds have then been used to calculate the effective driver gas pressure and temperature after diaphragm rupture. Since the driver gas is typically helium, or a mixture of helium and argon, and the test gas is also helium, ideal gas assumptions can be made without significant loss of accuracy. The technique is applicable to tuned free-piston drivers with a simple area change, as well as those using orifice plates. It is shown that this technique can be quickly used to establish average working driver gas properties which produce very good estimates of actual driven shock speed, across a wide range of operating conditions. The use of orifice plates to control piston dynamics at high driver gas sound speeds is also discussed in the paper, and a simple technique for calculating the restriction required to modify an established safe condition for use with lighter gases, such as pure helium, is presented.

Development of free-piston Stirling engine performance and optimization codes based on Martini simulation technique

Science.gov (United States)

Martini, William R.

1989-01-01

A FORTRAN computer code is described that could be used to design and optimize a free-displacer, free-piston Stirling engine similar to the RE-1000 engine made by Sunpower. The code contains options for specifying displacer and power piston motion or for allowing these motions to be calculated by a force balance. The engine load may be a dashpot, inertial compressor, hydraulic pump or linear alternator. Cycle analysis may be done by isothermal analysis or adiabatic analysis. Adiabatic analysis may be done using the Martini moving gas node analysis or the Rios second-order Runge-Kutta analysis. Flow loss and heat loss equations are included. Graphical display of engine motions and pressures and temperatures are included. Programming for optimizing up to 15 independent dimensions is included. Sample performance results are shown for both specified and unconstrained piston motions; these results are shown as generated by each of the two Martini analyses. Two sample optimization searches are shown using specified piston motion isothermal analysis. One is for three adjustable input and one is for four. Also, two optimization searches for calculated piston motion are presented for three and for four adjustable inputs. The effect of leakage is evaluated. Suggestions for further work are given.

Supercritical waste oxidation pump investigation

International Nuclear Information System (INIS)

Thurston, G.; Garcia, K.

1993-02-01

This report investigates the pumping techniques and pumping equipment that would be appropriate for a 5,000 gallon per day supercritical water oxidation waste disposal facility. The pumps must boost water, waste, and additives from atmospheric pressure to approximately 27.6 MPa (4,000 psia). The required flow ranges from 10 gpm to less than 0.1 gpm. For the higher flows, many commercial piston pumps are available. These pumps have packing and check-valves that will require periodic maintenance; probably at 2 to 6 month intervals. Several commercial diaphragm pumps were also discovered that could pump the higher flow rates. Diaphragm pumps have the advantage of not requiring dynamic seals. For the lower flows associated with the waste and additive materials, commercial diaphragm pumps. are available. Difficult to pump materials that are sticky, radioactive, or contain solids, could be injected with an accumulator using an inert gas as the driving mechanism. The information presented in this report serves as a spring board for trade studies and the development of equipment specifications

49 CFR 229.55 - Piston travel.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Piston travel. 229.55 Section 229.55... Piston travel. (a) Brake cylinder piston travel shall be sufficient to provide brake shoe clearance when... piston travel may not exceed 11/2 inches less than the total possible piston travel. The total possible...

Calculation of the Thermal Loading of the Cylinder-Piston Group of the Automobile Engine

Science.gov (United States)

Barchenko, F. B.; Bakulin, V. N.

2017-05-01

We propose a mathematical model for calculating thermal loods of parts of the cylinder-piston group of the automobile engine operating under unstable conditions in its complete life cycle. Methods have been described for calculating the boundary conditions to determine the thermal state of the parts of the cylinder-piston group of such an engine with the use of theoretical formulas, empirical and semiempirical relations, and tabulated data. In modeling, we calculated the work of all systems of the engine (pumps, pipelines, heat exchangers) influencing directly or indirectly the thermal state of its cylinder-piston group. The nonstationary thermal state was calculated once in the operating cycle of the engine with the use of the cycle-averaged values of the local heat transfer coefficients and the resulting temperature of the medium. The personal computer counting time for one time step of a transport diesel engine of typical design with a number of units of the order of 500 was 5 s.

Free-piston cutting machine

Science.gov (United States)

Ciccarelli, Gaby; Subudhi, Manomohan; Hall, Robert E.

2000-01-01

A cutting machine includes a gun barrel for receiving a projectile. A compression tube is disposed in flow communication with the barrel and includes a piston therein. A reservoir is disposed in flow communication with the tube and receives a first gas under pressure. A second gas fills the compression tube on a front face of the piston. And, the pressurized first gas is discharged into the tube on a back face of the piston to accelerate the piston through the tube for compressing the second gas, and in turn launching the projectile through the barrel to impact a workpiece.

Performance Analysis of a Wind Turbine Driven Swash Plate Pump for Large Scale Offshore Applications

International Nuclear Information System (INIS)

Buhagiar, D; Sant, T

2014-01-01

This paper deals with the performance modelling and analysis of offshore wind turbine-driven hydraulic pumps. The concept consists of an open loop hydraulic system with the rotor main shaft directly coupled to a swash plate pump to supply pressurised sea water. A mathematical model is derived to cater for the steady state behaviour of entire system. A simplified model for the pump is implemented together with different control scheme options for regulating the rotor shaft power. A new control scheme is investigated, based on the combined use of hydraulic pressure and pitch control. Using a steady-state analysis, the study shows how the adoption of alternative control schemes in a the wind turbine-hydraulic pump system may result in higher energy yields than those from a conventional system with an electrical generator and standard pitch control for power regulation. This is in particular the case with the new control scheme investigated in this study that is based on the combined use of pressure and rotor blade pitch control

Quantitative assessment of haemolysis secondary to modern infusion pumps.

Science.gov (United States)

Poder, T G; Boileau, J-C; Lafrenière, R; Thibault, L; Carrier, N; de Grandmont, M-J; Beauregard, P

2017-04-01

Although most studies have shown that little haemolysis is induced by infusion pumps, there are some notable exceptions. Only limited data are available on the actual infusion pumps that are most used in hospitals in Quebec and elsewhere, namely, the Infusomat ® Space (peristaltic), Plum A+™ (piston) and Colleague ® CXE (shuttle) pumps. Haemolysis and potassium levels were compared before and after the use of the three different infusion pumps. Using 135 units of packed red blood cells (RBCs) aged from 10 to 28 days, 27 measurements were taken for each pump at various flow rates (30, 60, 150, 300 and 450 ml/h) and were compared with measurements taken before using the pumps. The range of flow rates was chosen to cover those of paediatric and adult transfusions. The shuttle- and piston-type pumps resulted in low haemolysis levels. The peristaltic-type pump produced significantly more haemolysis, which worsened at low flow rates, but the absolute value of haemolysis remained within the range recommended by the regulatory agencies in North America and Europe. Approximately two-thirds of the haemolysis produced by the peristaltic-type pump seemed to be secondary to the use of an antisiphon valve (ASV) on the transfusion line recommended by the manufacturer. Potassium levels did not increase with the use of the pumps. Modern infusion pumps widely used in hospitals in Quebec and elsewhere produce non-threatening levels of haemolysis during the transfusion of packed RBCs aged from 10 to 28 days. ASVs appear to induce additional haemolysis, and we do not recommend using them for blood transfusion. © 2017 International Society of Blood Transfusion.

Cooled-Spool Piston Compressor

Science.gov (United States)

Morris, Brian G.

1994-01-01

Proposed cooled-spool piston compressor driven by hydraulic power and features internal cooling of piston by flowing hydraulic fluid to limit temperature of compressed gas. Provides sufficient cooling for higher compression ratios or reactive gases. Unlike conventional piston compressors, all parts of compressed gas lie at all times within relatively short distance of cooled surface so that gas cooled more effectively.

Interaction of Vortex Ring with Cutting Plate

Science.gov (United States)

Musta, Mustafa

2015-11-01

The interaction of a vortex ring impinging on a thin cutting plate was made experimentally using Volumetric 3-component Velocitmetry (v3v) technique. The vortex rings were generated with piston-cylinder vortex ring generator using piston stroke-to-diameter ratios and Re at 2-3 and 1500 - 3000, respectively. The cutting of vortex rings below center line leads to the formation of secondary vortices on each side of the plate which is look like two vortex rings, and a third vortex ring propagates further downstream in the direction of the initial vortex ring, which is previously showed by flow visualization study of Weigand (1993) and called ``trifurcation''. Trifurcation is very sensitive to the initial Reynolds number and the position of the plate with respect to the vortex ring generator pipe. The present work seeks more detailed investigation on the trifurcation using V3V technique. Conditions for the formation of trifurcation is analyzed and compared with Weigand (1993). The formed secondary vortex rings and the propagation of initial vortex ring in the downstream of the plate are analyzed by calculating their circulation, energy and trajectories.

HEMOPERFUSION DURING CORONARY ANGIOPLASTY - 1ST EUROPEAN EXPERIENCE WITH A NEW HEMOPERFUSION PUMP

NARCIS (Netherlands)

DEMUINCK, ED; MEEDER, J; MAGIELSE, C; BOM, VJJ; VANDIJK, RB; VERKERKE, GJ; LIE, KI

Hemolysis tests with fresh human blood were performed in vitro with a new 5 ml, piston-type hemoperfusion pump, designed to prevent myocardial ischemia during coronary angioplasty. Despite driving pressures greater than 3 atmospheres, shear stress greater than 200 Pa, turbulent pump flow, and the

Improvement in thermal fatigue resistance of cast iron piston; Chutetsu piston no tainetsu hiro sekkei

Energy Technology Data Exchange (ETDEWEB)

Amano, K; Uosaki, Y; Takeshige, N [Mazda Motor Corp., Hiroshima (Japan)

1997-10-01

Cast iron piston is superior in reduction of diesel engine emission to aluminum piston because of its characteristic of heat insulation. In order to study thermal fatigue characteristics of cast iron, thermal fatigue tests were carried out on two kinds of ferrite ductile cast iron. Differences between cast iron piston and aluminum piston in thermal fatigue resistance have been investigated by using FEM analysis. 5 refs., 14 figs., 1 tab.

Sibling cycle piston and valving method

Science.gov (United States)

Mitchell, Matthew P. (Inventor); Bauwens, Luc (Inventor)

1990-01-01

A double-acting, rotating piston reciprocating in a cylinder with the motion of the piston providing the valving action of the Sibling Cycle through the medium of passages between the piston and cylinder wall. The rotating piston contains regenerators ported to the walls of the piston. The piston fits closely in the cylinder at each end of the cylinder except in areas where the wall of the cylinder is relieved to provide passages between the cylinder wall and the piston leading to the expansion and compression spaces, respectively. The piston reciprocates as it rotates. The cylinder and piston together comprise an integral valve that seqentially opens and closes the ports at the ends of the regenerators alternately allowing them to communicate with the expansion space and compression space and blocking that communication. The relieved passages in the cylinder and the ports in the piston are so arranged that each regenerator is sequentially (1) charged with compressed working gas from the compression space; (2) isolated from both expansion and compression spaces; (3) discharged of working gas into the expansion space; and (4) simultaneously charged with working gas from the expansion space while being discharged of working gas into the compression space, in the manner of the Sibling Cycle. In an alterate embodiment, heat exchangers are external to the cylinder and ports in the cylinder wall are alternately closed by the wall of the piston and opened to the expansion and compression spaces through relieved passages in the wall of the reciprocating, rotating piston.

Pressure heat pumping in the orifice pulse-tube refrigerator

International Nuclear Information System (INIS)

Boer, P.C.T. de

1996-01-01

The mechanism by which heat is pumped as a result of pressure changes in an orifice pulse-tube refrigerator (OPTR) is analyzed thermodynamically. The thermodynamic cycle considered consists of four steps: (1) the pressure is increased by a factor π 1 due to motion of a piston in the heat exchanger at the warm end of the regenerator; (2) the pressure is decreased by a factor π 2 due to leakage out of the orifice; (3) the pressure is further decreased due to motion of the piston back to its original position; (4) the pressure is increased to its value at the start of the cycle due to leakage through the orifice back into the pulse tube. The regenerator and the heat exchangers are taken to be perfect. The pressure is assumed to be uniform during the entire cycle. The temperature profiles of the gas in the pulse tube after each step are derived analytically. Knowledge of the temperature at which gas enters the cold heat exchanger during steps 3 and 4 provides the heat removed per cycle from this exchanger. Knowledge of the pressure as a function of piston position provides the work done per cycle by the piston. The pressure heat pumping mechanism considered is effective only in the presence of a regenerator. Detailed results are presented for the heat removed per cycle, for the coefficient of performance, and for the refrigeration efficiency as a function of the compression ratio π 1 and the expansion ratio π 2 . Results are also given for the influence on performance of the ratio of specific heats. The results obtained are compared with corresponding results for the basic pulse-tube refrigerator (BPTR) operating by surface heat pumping

A study on the piston ring wear in automotive engine Seat 1500 CA by means of radioactive tracer technique; Estudio del desgaste de segmentos en motor Seat 1500 CA mediante trazadores radiactivos

Energy Technology Data Exchange (ETDEWEB)

Val Cob, M del; Chul, Y; Fuentes Figuera de Vargas, J.

1971-07-01

The iron side wear in the chromium-plated top compression ring has been a matter of interest for the engine makers and it has been required by them to investigate the wear characteristics of the chromium-plated piston ring. Meanwhile, Bureau of Nuclear Energy in Spain (Junta de Energia Nuclear) and Seat Car Manufacturing Company (Sociedad Espanola de Automoviles de Turismo) agreed to study the wear characteristics of chromium-plated piston ring of type CA gasoline engine for Seat 1500 car by means of radioactive tracer technique. (Author) 9 refs.

Design of Piston Ring Friction Tester Apparatus

DEFF Research Database (Denmark)

Klit, Peder

2006-01-01

One of the major prerequisites for calculating piston ring friction is a good description of the tribological situation. Piston rings operate in three different lubrication regimes and the theoretical models should be capable to describe this. A very important condition for describing the frictio......One of the major prerequisites for calculating piston ring friction is a good description of the tribological situation. Piston rings operate in three different lubrication regimes and the theoretical models should be capable to describe this. A very important condition for describing...... the frictional behavior of a piston ring correctly is knowledge about the amount of lubricant present. For piston rings the external load may be established by measuring the pressure distribution, i.e. the pressure drop in the piston ring package. Speed and temperature may also be established. The amount...... available is reflected in the friction absorbed in the bearing. The following properties will be measured: Oil fillm thickness - along liner (axial variation), oil film thickness - along piston ring (circumferential variation), piston tilt, temperature of piston rings and liner, pressure at piston lands...

Characterization of subvisible particle formation during the filling pump operation of a monoclonal antibody solution.

Science.gov (United States)

Nayak, Arpan; Colandene, James; Bradford, Victor; Perkins, Melissa

2011-10-01

Characterization and control of aggregate and subvisible particle formation during fill-finish process steps are important for biopharmaceutical products. The filling step is of key importance as there is no further filtration of the drug product beyond sterile filtration. Filling processes can impact product quality by introducing physical stresses such as shear, friction, and cavitation. Other detrimental factors include temperature generated in the process of filling, foaming, and contact with filling system materials, including processing aids such as silicone oil. Certain pumps may shed extrinsic particles that may lead to heterogeneous nucleation-induced aggregation. In this work, microflow imaging, size-exclusion chromatography (SEC), and turbidimetry were utilized to quantify subvisible particles, aggregation, and opalescence, respectively. The filling process was performed using several commonly used filling systems, including rotary piston pump, rolling diaphragm pump, peristaltic pump, and time-pressure filler. The rolling diaphragm pump, peristaltic pump, and time-pressure filler generated notably less protein subvisible particles than the rotary piston pump, although no change in aggregate content by SEC was observed by any pump. An extreme increase in subvisible particles was also reflected in an increase in turbidity. Copyright © 2011 Wiley-Liss, Inc.

49 CFR 230.76 - Piston travel.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Piston travel. 230.76 Section 230.76... Tenders Brake and Signal Equipment § 230.76 Piston travel. (a) Minimum piston travel. The minimum piston travel shall be sufficient to provide proper brake shoe clearance when the brakes are released. (b...

Design of a high-pressure circulating pump for viscous liquids.

Science.gov (United States)

Seifried, Bernhard; Temelli, Feral

2009-07-01

The design of a reciprocating dual action piston pump capable of circulating viscous fluids at pressures of up to 34 MPa (5000 psi) and temperatures up to 80 degrees C is described. The piston of this pump is driven by a pair of solenoids energized alternatively by a 12 V direct current power supply controlled by an electronic controller facilitating continuously adjustable flow rates. The body of this seal-less pump is constructed using off-the-shelf parts eliminating the need for custom made parts. Both the electronic controller and the pump can be assembled relatively easily. Pump performance has been evaluated at room temperature (22 degrees C) and atmospheric pressure using liquids with low and moderately high viscosities, such as ethanol and corn oil, respectively. At ambient conditions, the pump delivered continuous flow of ethanol and corn oil at a flow rate of up to 170 and 17 cm3/min, respectively. For pumping viscous fluids comparable to corn oil, an optimum reciprocation frequency was ascertained to maximize flow rate. For low viscosity liquids such as ethanol, a linear relationship between the flow rate and reciprocation frequency was determined up to the maximum reciprocation frequency of the pump. Since its fabrication, the pump has been used in our laboratory for circulating triglycerides in contact with supercritical carbon dioxide at pressures of up to 25 MPa (3600 psi) and temperatures up to 70 degrees C on a daily basis for a total of more than 1500 h of operation functioning trouble free.

Fine structures of the ejaculatory sac and sperm pump of the scorpionfly Panorpa liui Hua (Mecoptera: Panorpidae).

Science.gov (United States)

Shen, Jian; Hua, Baozhen

2013-08-01

Male adults of Panorpidae possess a special sperm pump, through which the males transfer liquid sperm to the females. However, the structures of the sperm pump and the transfer mechanism have not been satisfactorily elucidated hitherto. In this paper the structures of the ejaculatory sac and sperm pump of the scorpionfly Panorpa liui Hua were investigated using light microscopy and scanning electron microscopy. The ejaculatory sac is located between the basal end of the paired vasa deferentia and the aedeagus, comprising a small anterior part and a large posterior part. The anterior part is simple and functions only as a channel for sperm transfer. The epithelial cells of the large posterior part likely have secretory functions. The sperm pump is formed by the posterior region of the ejaculatory sac and derivates of the genital field, which enclose the pumping chamber, a piston and the associated muscles. The orifice of the ejaculatory duct lies ventrad of the piston. The piston of the sperm pump is heavily sclerotized and controlled by two antagonistic muscle pairs. A pair of simple tubular accessory glands opens to the pumping chamber. Two well-developed sex pheromone glands are located on the ventral side of the ejaculatory sac, and are composed of two fan-shaped lamellae. The epithelium of the sex pheromone glands is single-layered, and forms densely filamentous processes. The ejaculation mechanism is briefly discussed based on the morphology of ejaculatory sac and sperm pump. Copyright © 2013 Elsevier Ltd. All rights reserved.

External vortex pumping by oscillating plate arrays of mayfly nymphs

Science.gov (United States)

Sensenig, Andrew; Kiger, Ken; Shultz, Jeffrey

2009-11-01

Mayfly nymphs are aquatic insects, many of which can generate ventilation currents by beating two linear arrays of external plate-like gills. The oscillation Reynolds number associated with the gill motion changes with animal size, varying from Re ˜ 2 to 50 depending on age and species. Thus mayflies provide a novel system model for studying ontogenetic changes in pumping mechanisms associated with transitions from a more viscous- to inertia-dominated flow. Observation of the 3-D kinematics of the gill motion of the species C. triangulifer reveal that the mayfly makes a transition in stroke motion when Re>5, with a corresponding shift in mean flow from the ventral to the dorsal direction. Time-resolved PIV measurements within the inter-gill space reveal the basic elements of the flow consist of vortex rings generated by the strokes of the individual gills. For the larger Re case, the phasing of the plate motion generates a complex array of small vortices that interact to produce an intermittent dorsally directed jet. For Restroke kinematics. Thus we argue the transition in the kinematics is a reflection of a single mechanism adapted over the traversed Re range, rather than a shift to a completely new mechanism. This work is supported by the NSF under grant CBET-0730907.

Drift stabilizer for reciprocating free-piston devices

Science.gov (United States)

Ward, William C.; Corey, John A.; Swift, Gregory W.

2003-05-20

A free-piston device has a stabilized piston drift. A piston having a frequency of reciprocation over a stroke length and with first and second sides facing first and second variable volumes, respectively, for containing a working fluid defining an acoustic wavelength at the frequency of reciprocation. A bypass tube waveguide connects the first and second variable volumes at all times during reciprocation of the piston. The waveguide has a relatively low impedance for steady flow and a relatively high impedance for oscillating flow at the frequency of reciprocation of the piston, so that steady flow returns fluid leakage from about the piston between the first and second volumes while oscillating flow is not diverted through the waveguide. Thus, net leakage about the piston is returned during each stroke of the piston while oscillating leakage is not allowed and pressure buildup on either the first or second side of the piston is avoided to provide a stable piston location.

Solar photovoltaic water pumping system using a new linear actuator

OpenAIRE

Andrada Gascón, Pedro; Castro, Javier

2007-01-01

In this paper a photovoltaic solar pumping system using a new linear actuator is presented. This linear actuator is a double-sided flat two-phase variable-reluctance linear stepper motor that moves a piston-type water pump with the help of a rope, a pulley and a counterweight. The entire actuator pump ensemble is controlled by a simple electronic unit that manages the electric power generated by a photovoltaic array. The proposed system is suitable for rural communities in developing...

Overview of Multi-Kilowatt Free-Piston Stirling Power Conversion Research at Glenn Research Center

Science.gov (United States)

Geng, Steven M.; Mason, Lee S.; Dyson, Rodger W.; Penswick, L. Barry

2008-01-01

As a step towards development of Stirling power conversion for potential use in Fission Surface Power (FSP) systems, a pair of commercially available 1 kW class free-piston Stirling convertors and a pair of commercially available pressure wave generators (which will be plumbed together to create a high power Stirling linear alternator test rig) have been procured for in-house testing at Glenn Research Center (GRC). Delivery of both the Stirling convertors and the linear alternator test rig is expected by October 2007. The 1 kW class free-piston Stirling convertors will be tested at GRC to map and verify performance. The convertors will later be modified to operate with a NaK liquid metal pumped loop for thermal energy input. The high power linear alternator test rig will be used to map and verify high power Stirling linear alternator performance and to develop power management and distribution (PMAD) methods and techniques. This paper provides an overview of the multi-kilowatt free-piston Stirling power conversion work being performed at GRC.

Researches on the Piston Ring

Science.gov (United States)

Ehihara, Keikiti

1944-01-01

In internal combustion engines, steam engines, air compressors, and so forth, the piston ring plays an important role. Especially, the recent development of Diesel engines which require a high compression pressure for their working, makes, nowadays, the packing action of the piston ring far more important than ever. Though a number of papers have been published in regard to researches on the problem of the piston ring, none has yet dealt with an exact measurement of pressure exerted on the cylinder wall at any given point of the ring. The only paper that can be traced on this subject so far is Mr. Nakagawa's report on the determination of the relative distribution of pressure on the cylinder wall, but the measuring method adopted therein appears to need further consideration. No exact idea has yet been obtained as to how the obturation of gas between the piston and cylinder, the frictional resistance of the piston, and the wear of the cylinder wall are affected by the intensity and the distribution of the radial pressure of the piston ring. Consequently, the author has endeavored, by employing an apparatus of his own invention, to get an exact determination of the pressure distribution of the piston ring. By means of a newly devised ring tester, to which piezoelectricity of quartz was applied, the distribution of the radial pressure of many sample rings on the market was accurately determined. Since many famous piston rings show very irregular pressure distribution, the author investigated and achieved a manufacturing process of the piston ring which will exert uniform pressure on the cylinder wall. Temperature effects on the configuration and on the mean spring power have also been studied. Further, the tests were performed to ascertain how the gas tightness of the piston ring may be affected by the number or spring power. The researches as to the frictional resistance between the piston ring and the cylinder wall were carried out, too. The procedure of study, and

Carbon/Carbon Pistons for Internal Combustion Engines

Science.gov (United States)

Taylor, A. H.

1986-01-01

Carbon/carbon piston performs same function as aluminum pistons in reciprocating internal combustion engines while reducing weight and increasing mechanical and thermal efficiencies of engine. Carbon/carbon piston concept features low piston-to-cylinder wall clearance - so low piston rings and skirts unnecessary. Advantages possible by negligible coefficient of thermal expansion of carbon/carbon.

Development and Experimental Investigation of a Two-Stroke Opposed-Piston Free-Piston Engine

OpenAIRE

Schneider, Stephan; Chiodi, Marco; Friedrich, Horst E.; Bargende, Michael

2016-01-01

The proposed paper deals with the development process and initial measurement results of an opposed-piston combustion engine for application in a Free-Piston Linear Generator (FPLG). The FPLG, which is being developed at the German Aerospace Center (DLR), is an innovative internal combustion engine for a fuel based electrical power supply. With its arrangement, the pistons freely oscillate between the compression chamber of the combustion unit and a gas spring with no mechanical coupling like...

New Configurations of Micro Plate-Fin Heat Sink to Reduce Coolant Pumping Power

Science.gov (United States)

Rezania, A.; Rosendahl, L. A.

2012-06-01

The thermal resistance of heat exchangers has a strong influence on the electric power produced by a thermoelectric generator (TEG). In this work, a real TEG device is applied to three configurations of micro plate-fin heat sink. The distance between certain microchannels is varied to find the optimum heat sink configuration. The particular focus of this study is to reduce the coolant mass flow rate by considering the thermal resistances of the heat sinks and, thereby, to reduce the coolant pumping power in the system. The three-dimensional governing equations for the fluid flow and the heat transfer are solved using the finite-volume method for a wide range of pressure drop laminar flows along the heat sink. The temperature and the mass flow rate distribution in the heat sink are discussed. The results, which are in good agreement with previous computational studies, show that using suggested heat sink configurations reduces the coolant pumping power in the system.

Theoretical study on device efficiency of pulsed liquid jet pump

International Nuclear Information System (INIS)

Gao Chuanchang; Lu Hongqi; Wang Shicheng; Cheng Mingchuan

2001-01-01

The influence of the main factors on device efficiency of pulsed liquid jet pump with gas-liquid piston is analysed, the theoretical equation and its time-averaged solution of pulsed liquid jet pump device efficiency are derived. The theoretical and experimental results show that the efficiency of transmission of energy and mass to use pulsed jet is greatly raised, compared with steady jet, in the same device of liquid jet pump. The calculating results of time-averaged efficiency of pulsed liquid jet pump are approximately in agreement with the experimental results in our and foreign countries

A High Performance Pulsatile Pump for Aortic Flow Experiments in 3-Dimensional Models.

Science.gov (United States)

Chaudhury, Rafeed A; Atlasman, Victor; Pathangey, Girish; Pracht, Nicholas; Adrian, Ronald J; Frakes, David H

2016-06-01

Aortic pathologies such as coarctation, dissection, and aneurysm represent a particularly emergent class of cardiovascular diseases. Computational simulations of aortic flows are growing increasingly important as tools for gaining understanding of these pathologies, as well as for planning their surgical repair. In vitro experiments are required to validate the simulations against real world data, and the experiments require a pulsatile flow pump system that can provide physiologic flow conditions characteristic of the aorta. We designed a newly capable piston-based pulsatile flow pump system that can generate high volume flow rates (850 mL/s), replicate physiologic waveforms, and pump high viscosity fluids against large impedances. The system is also compatible with a broad range of fluid types, and is operable in magnetic resonance imaging environments. Performance of the system was validated using image processing-based analysis of piston motion as well as particle image velocimetry. The new system represents a more capable pumping solution for aortic flow experiments than other available designs, and can be manufactured at a relatively low cost.

Development of a hybrid chemical/mechanical heat pump

Science.gov (United States)

Grzyll, Lawrence R.; Silvestri, John J.; Scaringe, Robert P.

1991-01-01

The authors present the current development status of a hybrid chemical/mechanical heat pump for low-lift applications. The heat pump provides electronics cooling by evaporating a pure refrigerant from an absorbent/refrigerant mixture in a generator/cold plate. The current development focused on evaluation of absorbent/refrigerant pairs, corrosion testing, pump and compressor design, and electronic cold plate design. Two cycle configurations were considered. The first configuration utilized a standard mechanical compressor and pump. The second cycle configuration investigated pumps and compressors with non-moving parts. An innovative generator/cold plate design is also presented. The development to date shows that this cycle has about the same performance as standard vapor compression heat pumps with standard refrigerants but may have some performance and reliability advantages over vapor compression heat pumps.

Effect of pump limiter throat on pumping efficiency

International Nuclear Information System (INIS)

Ghendrih, P.; Grosman, A.; Samain, A.; Capes, H.; Morera, J.P.

1988-01-01

The necessary control of plasma edge density has led to the development of pump limiters to achieve this task. On Tore Supra, where a large part of the program is devoted to plasma edge studies, two types of such density control apparatus have been implemented, a set of pump limiters and the pumps associated to the ergodic divertor (magnetically assisted pump limiters). Generally two different kinds of pump limiters can be used, those with a throat which drives the plasma from the open edge plasma (SOL) to the neutralizer plate, and those without or with a very short throat. We are interested here in this aspect of the pump limiter concept, i.e. on the throat effect on neutral density build-up in the vicinity of the pumping plates (and hence on pumping efficieny). The underlying idea of this throat effect can be readily understood; indeed while the neutral capture in pump limiters without throats is only a ballistic effect, on expects the plasma to improve the efficiency of pump-limiters via plasma-neutral-sidewall interactions in the throat. This problem has been studied both numerically and analytically. The paper is divided as follows. In section 2, we describe the basic features of pump-limiters which are modelized by the numerical code Cezanne. Section 3 is devoted to the throat length effect considering in particular the neutral density profile in the throat and the neutral density buil-up as a function of the throat lenght. In section 4, we show that the plugging effect occurs for reasonnable values of throat lengths. An analytical value of the plugging length is discussed and compared to the values obtained numerically

An Electron-Diffraction Examination of Cast-Iron Piston Rings from Single-Cylinder Aircraft-Engine Tests

Science.gov (United States)

1945-02-01

found t; a great extent on thn ueed cylinder barrel ( SAE 4140 steel) and to a lesser extent on the top ohrmne- plated ring of the aesembl.yafter it had...on the used cylinder barrel (W 4140 steel) used in the tests and, to a lesser extent, on the used top chrome-platedring of the piston assembly. The

Performance optimization of grooved slippers for aero hydraulic pumps

Directory of Open Access Journals (Sweden)

Juan Chen

2016-06-01

Full Text Available A computational fluid dynamics (CFD simulation method based on 3-D Navier–Stokes equation and Arbitrary Lagrangian–Eulerian (ALE method is presented to analyze the grooved slipper performance of piston pump. The moving domain of grooved slipper is transformed into a fixed reference domain by the ALE method, which makes it convenient to take the effects of rotate speed, body force, temperature, and oil viscosity into account. A geometric model to express the complex structure, which covers the orifice of piston and slipper, vented groove and the oil film, is constructed. Corresponding to different oil film thicknesses calculated in light of hydrostatic equilibrium theory and boundary conditions, a set of simulations is conducted in COMSOL to analyze the pump characteristics and effects of geometry (groove width and radius, orifice size on these characteristics. Furthermore, the mechanics and hydraulics analyses are employed to validate the CFD model, and there is an excellent agreement between simulation and analytical results. The simulation results show that the sealing land radius, orifice size and groove width all dramatically affect the slipper behavior, and an optimum tradeoff among these factors is conducive to optimizing the pump design.

Two piston V-type Stirling engine

Science.gov (United States)

Corey, John A.

1987-01-01

A two piston Stirling engine which includes a heat exchanger arrangement placing the cooler and regenerator directly adjacent the compression space for minimal cold duct volume; a sealing arrangement which eliminates the need for piston seals, crossheads and piston rods; and a simplified power control system.

From aluminium pistons to steel pistons in trucks and ships; Von Aluminium- zum Stahlgrosskolben bei Nkw und Schiffen

Energy Technology Data Exchange (ETDEWEB)

Kortas, J. [Mahle GmbH, Markgroeningen (Germany). Produktkonstruktion Grossmotorenkomponenten

2005-11-01

This article is intended to show the development from one-piece aluminum pistons to composite pistons made from forged steel. With the Mahle pistons completely produced from forged steel, process-safe peak cylinder pressures of 25 MPa can be achieved. The steel piston development was initiated in the commercial vehicle sector and then extended to large engines with cylinder diameters up to 480 mm. (orig.)

Deriving guidelines for the design of plate evaporators in heat pumps using zeotropic mixtures

DEFF Research Database (Denmark)

Mancini, Roberta; Zühlsdorf, Benjamin; Jensen, Jonas Kjær

2018-01-01

This paper presents a derivation of design guidelines for plate heat exchangers used for evaporation of zeotropic mixtures in heat pumps. A mapping of combined heat exchanger and cycle calculations for different combinations of geometrical parameters and working fluids allowed estimating the trade....... It was found that the pressure drop limit leading to infeasible designs was dependent on the working fluid, thereby making it impossible to define a guideline based on maximum allowable pressure drops. It was found that economically feasible designs could be obtained by correlating the vapour Reynolds number...

Drive piston assembly for a valve actuator assembly

Science.gov (United States)

Sun, Zongxuan

2010-02-23

A drive piston assembly is provided that is operable to selectively open a poppet valve. The drive piston assembly includes a cartridge defining a generally stepped bore. A drive piston is movable within the generally stepped bore and a boost sleeve is coaxially disposed with respect to the drive piston. A main fluid chamber is at least partially defined by the generally stepped bore, drive piston, and boost sleeve. First and second feedback chambers are at least partially defined by the drive piston and each are disposed at opposite ends of the drive piston. At least one of the drive piston and the boost sleeve is sufficiently configured to move within the generally stepped bore in response to fluid pressure within the main fluid chamber to selectively open the poppet valve. A valve actuator assembly and engine are also provided incorporating the disclosed drive piston assembly.

Stabilizing Gas Bearings In Free-Piston Machines

Science.gov (United States)

Dhar, Manmohan

1995-01-01

Gas bearings and clearance seals between pistons and cylinders in free-piston machines designed to reduce undesired dynamic forces and torques on pistons, gas bearings, and cylinders. Circumferential grooves and drain galleries added to piston or cylinder in improved design. Provides stabilization without significant reduction in length of seal, or significant increase in leakage and consequent reduction of efficiency.

Integrated two-cylinder liquid piston Stirling engine

Energy Technology Data Exchange (ETDEWEB)

Yang, Ning; Rickard, Robert; Pluckter, Kevin; Sulchek, Todd, E-mail: todd.sulchek@me.gatech.edu [George W. Woodruff School of Mechanical Engineering and Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

2014-10-06

Heat engines utilizing the Stirling cycle may run on low temperature differentials with the capacity to function at high efficiency due to their near-reversible operation. However, current approaches to building Stirling engines are laborious and costly. Typically the components are assembled by hand and additional components require a corresponding increase in manufacturing complexity, akin to electronics before the integrated circuit. We present a simple and integrated approach to fabricating Stirling engines with precisely designed cylinders. We utilize computer aided design and one-step, planar machining to form all components of the engine. The engine utilizes liquid pistons and displacers to harness useful work from heat absorption and rejection. As a proof of principle of the integrated design, a two-cylinder engine is produced and characterized and liquid pumping is demonstrated.

Integrated two-cylinder liquid piston Stirling engine

International Nuclear Information System (INIS)

Yang, Ning; Rickard, Robert; Pluckter, Kevin; Sulchek, Todd

2014-01-01

Heat engines utilizing the Stirling cycle may run on low temperature differentials with the capacity to function at high efficiency due to their near-reversible operation. However, current approaches to building Stirling engines are laborious and costly. Typically the components are assembled by hand and additional components require a corresponding increase in manufacturing complexity, akin to electronics before the integrated circuit. We present a simple and integrated approach to fabricating Stirling engines with precisely designed cylinders. We utilize computer aided design and one-step, planar machining to form all components of the engine. The engine utilizes liquid pistons and displacers to harness useful work from heat absorption and rejection. As a proof of principle of the integrated design, a two-cylinder engine is produced and characterized and liquid pumping is demonstrated.

Integrated two-cylinder liquid piston Stirling engine

Science.gov (United States)

Yang, Ning; Rickard, Robert; Pluckter, Kevin; Sulchek, Todd

2014-10-01

Heat engines utilizing the Stirling cycle may run on low temperature differentials with the capacity to function at high efficiency due to their near-reversible operation. However, current approaches to building Stirling engines are laborious and costly. Typically the components are assembled by hand and additional components require a corresponding increase in manufacturing complexity, akin to electronics before the integrated circuit. We present a simple and integrated approach to fabricating Stirling engines with precisely designed cylinders. We utilize computer aided design and one-step, planar machining to form all components of the engine. The engine utilizes liquid pistons and displacers to harness useful work from heat absorption and rejection. As a proof of principle of the integrated design, a two-cylinder engine is produced and characterized and liquid pumping is demonstrated.

Piston engines and gas turbines

Energy Technology Data Exchange (ETDEWEB)

Shmelev, V.M.

1999-07-01

The concept of a free piston engine utilising overlean fuel-air mixture and using entropy rising compression is examined. An analysis was made of engine operation. The high compression parameters can be reached under compression of the mixture by a free piston to ensure the space heat release occurs from the mixture is not capable to self-combustion. It is shown that two stage entropy rising compression allows to reduce the final compression pressure and increase a perfomance of the piston engine. (orig.)

Electromagnetic circulation pump for corrosive gases

International Nuclear Information System (INIS)

Noe, P.; Delafosse, D.; Deletre, G.

1965-01-01

In order to transport very corrosive products (fluorinated compounds) we have been led to develop a totally metallic circulation pump capable of operating at above room temperatures and with a molecular vacuum. We have aimed at maximum simplicity both in its conception and in its operation. The tests showed that the compression ratios produced, although not high are interesting (1.5 at a pressure of 100 torr) (see curve I). The flow-rate range is very wide: about one hundred ccs/atm/min. to 3000 ccs/atm/min. (see curves IV, V, VI). The desorption of this pump presents no difficulty if both the aspiration and the reject sides are pumped together. A hole of 2 mm diameter drilled in the piston makes it possible to desorb the space between the two segments. The price of this pump is not high: 1300 F, with the electrical cabinet. (authors) [fr

Free-piston engine

Science.gov (United States)

Van Blarigan, Peter

2001-01-01

A combustion system which can utilize high compression ratios, short burn durations, and homogeneous fuel/air mixtures in conjunction with low equivalence ratios. In particular, a free-piston, two-stroke autoignition internal combustion engine including an electrical generator having a linear alternator with a double-ended free piston that oscillates inside a closed cylinder is provided. Fuel and air are introduced in a two-stroke cycle fashion on each end, where the cylinder charge is compressed to the point of autoignition without spark plugs. The piston is driven in an oscillating motion as combustion occurs successively on each end. This leads to rapid combustion at almost constant volume for any fuel/air equivalence ratio mixture at very high compression ratios. The engine is characterized by high thermal efficiency and low NO.sub.x emissions. The engine is particularly suited for generating electrical current in a hybrid automobile.

Development of a gas fired Vuilleumier heat pump for residential heating

DEFF Research Database (Denmark)

Carlsen, Henrik

1989-01-01

A natural gas-driven heat pump based on the Vuilleumier principle has been developed for use in single-family houses. The pump has a heat output of 7.5 kW at a coefficient of performance of 1.62 based on the lower heat content of the gas fuel. The heat pump uses helium as working fluid at 20 MPa...... mean pressure, and it is designed as a semihermetic unit. A crank mechanism distinguished by very small loads on the piston rings was developed. The advantages and disadvantages of the Vuilleumier principle for heat-driven heat pumps are discussed. Results of the extensive experimental work...... are presented. A new 20 kW Vuilleumier heat pump is briefly described...

Improvements in or relating to pumps

International Nuclear Information System (INIS)

Norman, G.

1985-01-01

A diaphragm pump comprises a housing, a diaphragm peripherally secured in the housing and in the form of a laminate, one layer of greater elasticity than another, a rod extending from a central support through a wall of the housing for reciprocating the diaphragm. The central support engages the diaphragm to a transverse extent which is between one half and two thirds of the major transverse active dimension (ie radius) of the diaphragm, at least one of the parts diverging as it extends away from the diaphragm. A control mechanism is illustrated for a pair of pumps driven by one reciprocating piston under the influence of pneumatic pressure, reciprocation and the pump stroke/delivery stroke relationship being controlled by adjustable pressure restrictors acting on change-over spool valves. (author)

Stirling engine piston ring

Science.gov (United States)

Howarth, Roy B.

1983-01-01

A piston ring design for a Stirling engine wherein the contact pressure between the piston and the cylinder is maintained at a uniform level, independent of engine conditions through a balancing of the pressure exerted upon the ring's surface and thereby allowing the contact pressure on the ring to be predetermined through the use of a preloaded expander ring.

Performance characteristics of a continuous-flow fluidic pump

International Nuclear Information System (INIS)

Robinson, S.M.; Counce, R.M.; Smith, G.V.

1987-01-01

The fluidic pump is a type of positive-displacement pump in which basic fluid mechanics phenomena are utilized to eliminate valves and other moving parts that are exposed to the fluid being transferred. The version described in this article is powered by gas pressure serving as gas pistons and is virtually maintenance-free. It utilizes two displacement vessels and is designed to produce a steady and continuous liquid flow. This type of pump may be very useful for the transfer of radioactive or hazardous liquids where mechanical maintenance may be difficult or exposure of personnel to the fluid is undesirable. This paper presents experimental and model-predicted characteristics of such systems. The effects of several geometric parameters and operating conditions on the performance of the pump are briefly discussed

Spherical Casimir pistons

Energy Technology Data Exchange (ETDEWEB)

Dowker, J S, E-mail: dowker@man.ac.uk [Theory Group, School of Physics and Astronomy, University of Manchester, Manchester (United Kingdom)

2011-08-07

A piston is introduced into a spherical lune Casimir cavity turning it into two adjacent lunes separated by the (hemispherical) piston. On the basis of zeta-function regularization, the vacuum energy of the arrangement is finite for conformal propagation in spacetime. For even spheres this energy is independent of the angle of the lune. For odd dimensions it is shown that for all Neumann, or all Dirichlet, boundary conditions the piston is repelled or attracted by the nearest wall if d = 3, 7, ... or if d = 1, 5, ... , respectively. For hybrid N-D conditions these requirements are switched. If a mass is added, divergences arise which render the model suspect. The analysis, however, is relatively straightforward and involves the Barnes zeta function. The extension to finite temperatures is made and it is shown that for the 3, 7, ... series of odd spheres, the repulsion by the walls continues but that, above a certain temperature, the free energy acquires two minima symmetrically placed about the midpoint.

Spherical Casimir pistons

International Nuclear Information System (INIS)

Dowker, J S

2011-01-01

A piston is introduced into a spherical lune Casimir cavity turning it into two adjacent lunes separated by the (hemispherical) piston. On the basis of zeta-function regularization, the vacuum energy of the arrangement is finite for conformal propagation in spacetime. For even spheres this energy is independent of the angle of the lune. For odd dimensions it is shown that for all Neumann, or all Dirichlet, boundary conditions the piston is repelled or attracted by the nearest wall if d = 3, 7, ... or if d = 1, 5, ... , respectively. For hybrid N-D conditions these requirements are switched. If a mass is added, divergences arise which render the model suspect. The analysis, however, is relatively straightforward and involves the Barnes zeta function. The extension to finite temperatures is made and it is shown that for the 3, 7, ... series of odd spheres, the repulsion by the walls continues but that, above a certain temperature, the free energy acquires two minima symmetrically placed about the midpoint.

An intelligent displacement pumping film system: A new concept for enhancing heavy metal ion removal efficiency from liquid waste

International Nuclear Information System (INIS)

Wang, Zhongde; Feng, Yanting; Hao, Xiaogang; Huang, Wei; Guan, Guoqing; Abudula, Abuliti

2014-01-01

Highlights: • A new concept for design of an intelligent displacement pumping film was proposed. • As-prepared ESIX hybrid film system showed excellent Ni 2+ uptake/exclude rate. • Piston-like proton pumping effect existed in the prepared ESIX hybrid film. • The mechanism of the ion pumping effect was proved by XPS analysis. - Abstract: A concept of electrochemically switched ion exchange (ESIX) hybrid film system with piston-like proton pumping effect for the removal of heavy metal ions was proposed. Based on this concept, a novel ESIX hybrid film composed of layered alpha zirconium phosphate (α-Zr(HPO 4 ) 2 ; α-ZrP) nanosheets intercalated with a potential-responsive conducting polyaniline (PANI) was developed for the removal of Ni 2+ ions from wastewater. It is expected that the space between α-ZrP nanosheets acts as the reservoir for the functional ions while the intercalated PANI works as the potential-sensitive function element for piston-like proton pumping in such ESIX hybrid films. The prepared ESIX hybrid film showed an excellent property of rapid removal of Ni 2+ ions from wastewater with a high selectivity. The used film was simply regenerated by only altering the applied potential. The ion pumping effect for the ESIX of Ni 2+ ions using this kind of film was proved via XPS analysis. The proposed ESIX hybrid film should have high potential for the removal of Ni 2+ ions and/or other heavy metal ions from wastewater in various industrial processes

Improving Free-Piston Stirling Engine Power Density

Science.gov (United States)

Briggs, Maxwell H.

2016-01-01

Analyses and experiments demonstrate the potential benefits of optimizing piston and displacer motion in a free piston Stirling Engine. Isothermal analysis shows the theoretical limits of power density improvement due to ideal motion in ideal Stirling engines. More realistic models based on nodal analysis show that ideal piston and displacer waveforms are not optimal, often producing less power than engines that use sinusoidal piston and displacer motion. Constrained optimization using nodal analysis predicts that Stirling engine power density can be increased by as much as 58% using optimized higher harmonic piston and displacer motion. An experiment is conducted in which an engine designed for sinusoidal motion is forced to operate with both second and third harmonics, resulting in a maximum piston power increase of 14%. Analytical predictions are compared to experimental data showing close agreement with indirect thermodynamic power calculations, but poor agreement with direct electrical power measurements.

DEVELOPMENT OF A LINEAR COMPRESSOR FOR AIR CONDITIONERS AND HEAT PUMPS

Science.gov (United States)

The report discusses the design, building, testing, and delivering to the Environmental Protection Agency of a linear compressor for operation in a 3.0- ton (10.5 kW) residential air-conditioning and heat pumping system. The compressor design evolved from a linear resonant piston...

Designing an Electro-Hydraulic Control Module for an Open-Circuit Variable Displacement Pump

DEFF Research Database (Denmark)

Pedersen, Henrik Clemmensen; Andersen, Torben Ole; Hansen, Michael Rygaard

2005-01-01

, in the form of an electric control signal, under varying working conditions, when having access to engine speed and actual pump pressure. The paper presents a model of both the pump and the control module, along with design considerations on which linear controllers are developed for a worst point......This paper deals with the problem of designing an electric control module for a Sauer-Danfoss Series 45 H-frame open circuit axial piston pump. The purpose of the electric control module is to replace the existing hydro-mechanical (LS) regulator, and enable the pump to follow a reference pressure...

5-kWe Free-piston Stirling Engine Convertor

Science.gov (United States)

Chapman, Peter A.; Vitale, Nicholas A.; Walter, Thomas J.

2008-01-01

The high reliability, long life, and efficient operation of Free-Piston Stirling Engines (FPSEs) make them an attractive power system to meet future space power requirements with less mass, better efficiency, and less total heat exchanger area than other power convertor options. FPSEs are also flexible in configuration as they can be coupled with many potential heat sources and various heat input systems, heat rejection systems, and power management and distribution systems. Development of a 5-kWe Stirling Convertor Assembly (SCA) is underway to demonstrate the viability of an FPSE for space power. The design is a scaled-down version of the successful 12.5-kWe Component Test Power Converter (CTPC) developed under NAS3-25463. The ultimate efficiency target is 25% overall convertor efficiency (electrical power out over heat in). For the single cylinder prototype now in development, cost and time constraints required use of economical and readily available materials (steel versus beryllium) and components (a commercially available linear alternator) and thus lower efficiency. The working gas is helium at 150 bar mean pressure. The design consists of a displacer suspended on internally pumped gas bearings and a power piston/alternator supported on flexures. Non-contacting clearance seals are used between internal volumes. Heat to and from the prototype convertor is done via pumped liquid loops passing through shell and tube heat exchangers. The preliminary and detail designs of the convertor, controller, and support systems (heating loop, cooling loop, and helium supply system) are complete and all hardware is on order. Assembly and test of the prototype at Foster- Miller is planned for early 2008, when work will focus on characterizing convertor dynamics and steady-state operation to determine maximum power output and system efficiency. The device will then be delivered to Auburn University where assessments will include start-up and shutdown characterization and

Fault diagnosis of an intelligent hydraulic pump based on a nonlinear unknown input observer

Directory of Open Access Journals (Sweden)

Zhonghai MA

2018-02-01

Full Text Available Hydraulic piston pumps are commonly used in aircraft. In order to improve the viability of aircraft and energy efficiency, intelligent variable pressure pump systems have been used in aircraft hydraulic systems more and more widely. Efficient fault diagnosis plays an important role in improving the reliability and performance of hydraulic systems. In this paper, a fault diagnosis method of an intelligent hydraulic pump system (IHPS based on a nonlinear unknown input observer (NUIO is proposed. Different from factors of a full-order Luenberger-type unknown input observer, nonlinear factors of the IHPS are considered in the NUIO. Firstly, a new type of intelligent pump is presented, the mathematical model of which is established to describe the IHPS. Taking into account the real-time requirements of the IHPS and the special structure of the pump, the mechanism of the intelligent pump and failure modes are analyzed and two typical failure modes are obtained. Furthermore, a NUIO of the IHPS is performed based on the output pressure and swashplate angle signals. With the residual error signals produced by the NUIO, online intelligent pump failure occurring in real-time can be detected. Lastly, through analysis and simulation, it is confirmed that this diagnostic method could accurately diagnose and isolate those typical failure modes of the nonlinear IHPS. The method proposed in this paper is of great significance in improving the reliability of the IHPS. Keywords: Fault diagnosis, Hydraulic piston pump, Model-based, Nonlinear unknown input observer (NUIO, Residual error

Micro-Welding of Copper Plate by Frequency Doubled Diode Pumped Pulsed Nd:YAG Laser

Science.gov (United States)

Nakashiba, Shin-Ichi; Okamoto, Yasuhiro; Sakagawa, Tomokazu; Takai, Sunao; Okada, Akira

A pulsed laser of 532 nm wavelength with ms range pulse duration was newly developed by second harmonic generation of diode pumped pulsed Nd:YAG laser. High electro-optical conversion efficiency more than 13% could be achieved, and 1.5 kW peak power green laser pulse was put in optical fiber of 100 μm in diameter. In micro- welding of 1.0 mm thickness copper plate, a keyhole welding was successfully performed by 1.0 kW peak power at spot diameter less than 200 μm. The frequency doubled pulsed laser improved the processing efficiency of copper welding, and narrow and deep weld bead was stably obtained.

Observation of advanced particle removal rates in pump limiter simulation experiments

International Nuclear Information System (INIS)

Goebel, D.M.; Conn, R.W.

1984-05-01

The performance of particle removal schemes for density and impurity control in tokamaks and mirror machines depends strongly on the plasma parameters and local recycling near the plasma neutralizier plates and gas pumping ducts. The relationship between plasma density, electron temperature, ion energy and gas flow and particle removal rate through a pumping duct located near a plasma neutralizer plate has been experimentally investigated in the steady state plasma device PISCES. Results indicate that initially the particle removal by pumps at the end of the duct is proportional to the plasma flux to the plate. A nonlinear increase in the pumping rate occurs when the ionization mean free path for neutrals from the plate becomes less than the plasma radius. The transition from a transparent to an opaque plasma due to local ionization of the neutrals produced at the neutralizer plate greatly enhances the particle removal rate by recycling of the neutral gas as it flows away from the neutralizer plate or out of the pumping ducts. Parameters were varied to determine the importance of ballistic scattering of higher energy ions from the plate, but no effects were found in these experiments

An efficient linear power generator - Linear motor for oscillating piston machines; Effizienter Lineargenerator / Linearmotor fuer Kolbenmaschine - Schlussbericht

Energy Technology Data Exchange (ETDEWEB)

Lindegger, M.

2008-07-01

When an oscillating piston interacts with an electrical generator or motor, it is obvious that the electrical machine should also have linear motion, eliminating the disadvantage of a crankshaft. This work has two parts: construction of an efficient linear generator for a Stirling engine with a free piston and a theoretical study of the efficiency of linear motors for driving compressors. The Stirling engine and the linear generator have a continuous power of 1.3 kW{sub el}. With thermal peak power the planned 1.5 kW{sub el} are attained. The Project 'Stirling Free Piston Generator' for cogeneration will continue. Smaller linear motors with permanent magnets function without electronic control from single-phase AC net. The theoretical study shows how linear motors can be led out by linking the electric vector diagram with the pressure-volume diagram of the compressor. At a power level exceeding a few kW, a three-phase system with power electronics is more suitable. The frequency of oscillation is variable and lower than 50 Hz. The efficiency of the simulated linear motors lies in the range of efficiency class EFF1 of standard motors. The very high efficiencies of rotating motors with permanent magnets are not attained. The combination of the linear motor with an optimised thermal process leads to advantages regarding the efficiency. If a heat pump with linear drive system can operate with hot lubricating oil the losses in the heat exchangers are reduced. The Competence Center for Thermal Machines at Lucerne University of Applied Sciences and Arts shows great interest to pursue the project of a linear heat pump for small temperature differences. (author)

Thermal Fluctuations in Casimir Pistons

Science.gov (United States)

Lomnitz, M.; Villarreal, C.

2012-07-01

We present analytical and simple expressions to determine the free energy, internal energy, entropy, as well as the pressure acting at the interface of a perfectly conducting rectangular Casimir piston. We show that infrared divergencies linear in temperature become cancelled within the piston configuration, and show a continuous behavior consistent with intuitive expectations.

Integrated Free-Piston Generators: An Overview

Energy Technology Data Exchange (ETDEWEB)

Arshad, Waqas M.; Thelin, Peter; Sadarangani, Chandur [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Electrical Machines and Power Electronics; Baeckstroem, Thomas [ABB Group Services-Corporate Research, Vaesteraas (Sweden)

2002-08-01

The free-piston generator is an energy conversion device that integrates a combustion engine and an electrical generator into a single unit. Thereby the intermediary crankshaft stage present in conventional hybrid topologies is eliminated. This has benefits in efficiency, weight reduction, robustness, variable compression operation and multi-fuel possibilities. This paper presents the free-piston generator concepts, along with the expected benefits and drawbacks. A literature survey is provided. Results from a simplified combustion modeling process are presented in terms of piston motion profiles. These have implications upon the dimensioning and selection of an appropriate electrical machine. Specifications for the electrical machine are outlined. Some distinct electrical machine solutions are presented and discussed. An application of the free-piston generator in a series hybrid vehicle is also proposed.

Thermo-hydraulic free piston engine as a primary propulsion unit in mobile hydraulic drives; Die thermohydraulische Freikolbenmaschine - ein neues Antriebskonzept fuer hydraulische angetriebene Fahrzeuge

Energy Technology Data Exchange (ETDEWEB)

Brunner, H. [Technische Univ. Dresden (Germany)

2004-07-01

The principle function of a free piston engine was tested on a test stand. The engine can drive hydraulic loads as a primary aggregate in a storage-based constant pressure network. Its power is independent of the loads. The engine is operated in intermittent operation and at the optimal operating point. There are no idle or part-load fractions. Measurements so far have shown that the performance of the new system equals that of a current combination of internal combustion engine and axial piston pump in their optimal operating point. In cyclic operation, the performance is even better. (orig.)

Development of high pressure-high vacuum-high conductance piston valve for gas-filled radiation detectors

International Nuclear Information System (INIS)

Prasad, D N; Ayyappan, R; Kamble, L P; Singh, J P; Muralikrishna, L V; Alex, M; Balagi, V; Mukhopadhyay, P K

2008-01-01

Gas-filled radiation detectors need gas filling at pressures that range from few cms of mercury to as high as 25kg/cm 2 at room temperature. Before gas-filling these detectors require evacuation to a vacuum of the order of ∼1 x 10 -5 mbar. For these operations of evacuation and gas filling a system consisting of a vacuum pump with a high vacuum gauge, gas cylinder with a pressure gauge and a valve is used. The valve has to meet the three requirements of compatibility with high-pressure and high vacuum and high conductance. A piston valve suitable for the evacuation and gas filling of radiation detectors has been designed and fabricated to meet the above requirements. The stainless steel body (80mmx160mm overall dimensions) valve with a piston arrangement has a 1/2 inch inlet/outlet opening, neoprene/viton O-ring at piston face and diameter for sealing and a knob for opening and closing the valve. The piston movement mechanism is designed to have minimum wear of sealing O-rings. The valve has been hydrostatic pressure tested up to 75bars and has Helium leak rate of less than 9.6x10 -9 m bar ltr/sec in vacuum mode and 2x10 -7 mbar ltr/sec in pressure mode. As compared to a commercial diaphragm valve, which needed 3 hours to evacuate a 7 litre chamber to 2.5x10 -5 mbar, the new valve achieved vacuum 7.4x10 -6 mbar in the same time under the same conditions

Influence of Pressure Build-Up Time of Compression Chamber on Improving the Operation Frequency of a Single-Piston Hydraulic Free-Piston Engine

Directory of Open Access Journals (Sweden)

Hai-bo Xie

2013-01-01

Full Text Available A single-piston hydraulic free-piston engine with a two-cylinder four-stroke diesel engine as its driver is introduced. It takes the free-piston assembly a certain time to move after the pressure in the compression chamber starts to increase. The time difference between the pressure increasing and the piston starting to move is defined as the pressure build-up time. The characteristics of the pressure build-up time and its influence on the performance of the free-piston engine are introduced and analyzed. Based on the basic law of dynamics of the free-piston assembly, the parameters which influence the pressure build-up time are analyzed. And then improvement and optimization are proposed to shorten the pressure build-up time.

Coupled dynamic-multidimensional modelling of free-piston engine combustion

International Nuclear Information System (INIS)

Mikalsen, R.; Roskilly, A.P.

2009-01-01

Free-piston engines are under investigation by a number of research groups worldwide, as an alternative to conventional technology in applications such as electric and hydraulic power generation. The piston dynamics of the free-piston engine differ significantly from those of conventional engines, and this may influence in-cylinder gas motion, combustion and emissions formation. Due to the complex interaction between mechanics and thermodynamics, the modelling of free-piston engines is not straight-forward. This paper presents a novel approach to the modelling of free-piston engines through the introduction of solution-dependent mesh motion in an engine CFD code. The particular features of free-piston engines are discussed, and the model for engine dynamics implemented in the CFD code is described. Finally, the coupled solver is demonstrated through the modelling of a spark ignited free-piston engine generator

Coupled dynamic-multidimensional modelling of free-piston engine combustion

Energy Technology Data Exchange (ETDEWEB)

Mikalsen, R. [Sir Joseph Swan Institute for Energy Research, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom); Roskilly, A.P. [Sir Joseph Swan Institute for Energy Research, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom)], E-mail: tony.roskilly@ncl.ac.uk

2009-01-15

Free-piston engines are under investigation by a number of research groups worldwide, as an alternative to conventional technology in applications such as electric and hydraulic power generation. The piston dynamics of the free-piston engine differ significantly from those of conventional engines, and this may influence in-cylinder gas motion, combustion and emissions formation. Due to the complex interaction between mechanics and thermodynamics, the modelling of free-piston engines is not straight-forward. This paper presents a novel approach to the modelling of free-piston engines through the introduction of solution-dependent mesh motion in an engine CFD code. The particular features of free-piston engines are discussed, and the model for engine dynamics implemented in the CFD code is described. Finally, the coupled solver is demonstrated through the modelling of a spark ignited free-piston engine generator.

Transitions in low Re pumping by oscillating plate arrays of mayfly nymphs

Science.gov (United States)

Kiger, Ken; Sensenig, Andrew; Shultz, Jeffrey

2008-11-01

Mayfly nymphs are aquatic insects which alter behavior and metabolism to accommodate changes in ambient dissolved oxygen. Many species can generate a ventilation current to compensate for low oxygen levels by beating two linear arrays of plate-like gills that line the lateral edge of the abdomen. The oscillation Reynolds number associated with the gill motion changes with animal size, varying over a span of Re = 2 to 50 depending on age and species. Thus mayflies provide a novel system model for studying ontological changes in pumping mechanisms associated with transitions from a viscous- to inertia-dominated flow. Observation of the detailed 3-D kinematics of the gill motion of the species Centroptilum triangulifer reveal that the mayfly makes a marked transition in stroke motion when Re>5, with a corresponding shift in mean flow from the ventral to the dorsal direction. Results of the time-resolved flow within the inter-gill space shows that for Re>12 the plate motion generates a complex array of bound and shed vortices, which interact to produce an intermittent dorsally directed jet. For the Re<5, distinct bound vortices are still observed, but increased diffusive effects creates vortices which simultaneously envelope several gills, forcing a new flow pattern to emerge. Details of the flow mechanism and its implications will be discussed. This work is supported by NSF under grant CBET-0730907.

Improving Power Density of Free-Piston Stirling Engines

Science.gov (United States)

Briggs, Maxwell H.; Prahl, Joseph M.; Loparo, Kenneth A.

2016-01-01

Analyses and experiments demonstrate the potential benefits of optimizing piston and displacer motion in a free-piston Stirling Engine. Isothermal analysis shows the theoretical limits of power density improvement due to ideal motion in ideal Stirling engines. More realistic models based on nodal analysis show that ideal piston and displacer waveforms are not optimal, often producing less power than engines that use sinusoidal piston and displacer motion. Constrained optimization using nodal analysis predicts that Stirling engine power density can be increased by as much as 58 percent using optimized higher harmonic piston and displacer motion. An experiment is conducted in which an engine designed for sinusoidal motion is forced to operate with both second and third harmonics, resulting in a piston power increase of as much as 14 percent. Analytical predictions are compared to experimental data and show close agreement with indirect thermodynamic power calculations, but poor agreement with direct electrical power measurements.

Device to position selectively a tool carried by a vehicle moving on the perforated plate of a tube bundle

International Nuclear Information System (INIS)

Bernardin, M.

1985-01-01

The aim of the invention is an examination device for a tube bundle of an apparatus such as, but not restrictively, a steam generator, situated in a dangerous zone, e.g. radioactive and designed to be introduced into the water box of the said and placed against the perforated plate of the tube bundle by an operator working outside of the said apparatus and able to operate whatever the vertical or horizontal position of the tube plate. The device has a selectively positionable tool - carrying vehicle comprising pistons positioning fingers extendable into the tubes and mounted on extendable supports perpendicular to the pistons and to each other, and an articulated telescopic arm fixed at one end to a rotary mounting on the vehicle and at the other end to an access opening in the vessel containing the tube plate, to hold the vehicle against the plate [fr

Magnetic bearings for free-piston Stirling engines

Science.gov (United States)

Curwen, P. W.; Fleming, D. P.; Rao, D. K.; Wilson, D. S.

1992-01-01

The feasibility and efficacy of applying magnetic bearings to free-piston Stirling-cycle power conversion machinery currently being developed for long-term space missions are assessed. The study was performed for a 50-kWe Reference Stirling Space Power Converter (RSSPC) which currently uses hydrostatic gas bearings to support the reciprocating displacer and power piston assemblies. Active magnetic bearings of the attractive electromagnetic type are feasible for the RSSPC power piston. Magnetic support of the displacer assembly would require unacceptable changes to the design of the current RSSPC. However, magnetic suspension of both displacer and power piston is feasible for a relative-displacer version of the RSSPC. Magnetic suspension of the RSSPC power piston can potentially increase overall efficiency by 0.5 to 1 percent (0.1 to 0.3 efficiency points). Magnetic bearings will also overcome several operational concerns associated with hydrostatic gas bearing systems. These advantages, however, are accompanied by a 5 percent increase in specific mass of the RSSPC.

Pistons and engine testing

CERN Document Server

2016-01-01

The ever-increasing demands placed on combustion engines are just as great when it comes to this centerpiece—the piston. Achieving less weight or friction, or even greater wear resistance, requires in-depth knowledge of the processes taking place inside the engine, suitable materials, and appropriate design and manufacturing processes for pistons, including the necessary testing measures. It is no longer possible for professionals in automotive engineering to manage without specific expertise of this kind, whether they work in the field of design, development, testing, or maintenance. This technical book answers these questions in detail and in a very clear and comprehensible way. In this second, revised edition, every chapter has been revised and expanded. The chapter on “Engine testing”, for example, now include extensive results in the area of friction power loss measurement and lube oil consumption measurement. Contents Piston function, requirements, and types Design guidelines Simulation of the ope...

Investigation of thermal behaviour, pressure drop, and pumping power in a Cu nanofluid-filled solar flat-plate collector

Directory of Open Access Journals (Sweden)

Shamshirgaran S. Reza

2017-01-01

Full Text Available The evaluations of the performance of solar flat-plate collectors are reported in the literature. A computer program developed by MATLAB has been applied for modelling the performance of a solar collector under steady state laminar conditions. Results demonstrate that Cu-water nanofluid would be capable of boosting the thermal efficiency of the collector by 2.4% at 4% volume concentration in the case of using Cunanofluid instead of just water as the working fluid. It is noteworthy that, dispersing the nanoparticles into the water results in a higher pressure drop and, therefore, a higher power consumption for pumping the nanofluid within the collector. It has been estimated for the collector understudy, that the increase in the pressure drop and pumping power to be around 30%.

Improving Free-Piston Stirling Engine Specific Power

Science.gov (United States)

Briggs, Maxwell H.

2015-01-01

This work uses analytical methods to demonstrate the potential benefits of optimizing piston and/or displacer motion in a Stirling engine. Isothermal analysis was used to show the potential benefits of ideal motion in ideal Stirling engines. Nodal analysis is used to show that ideal piston and displacer waveforms are not optimal in real Stirling engines. Constrained optimization was used to identify piston and displacer waveforms that increase Stirling engine specific power.

Staged combustion with piston engine and turbine engine supercharger

Science.gov (United States)

Fischer, Larry E [Los Gatos, CA; Anderson, Brian L [Lodi, CA; O'Brien, Kevin C [San Ramon, CA

2011-11-01

A combustion engine method and system provides increased fuel efficiency and reduces polluting exhaust emissions by burning fuel in a two-stage combustion system. Fuel is combusted in a piston engine in a first stage producing piston engine exhaust gases. Fuel contained in the piston engine exhaust gases is combusted in a second stage turbine engine. Turbine engine exhaust gases are used to supercharge the piston engine.

A conceptual study of the potential for automotive-derived and free-piston Stirling engines in 30- to 400-kilowatt stationary power applications

Science.gov (United States)

Vatsky, A.; Chen, H. S.; Dineen, J.

1982-01-01

The technical feasibility of applying automotive-derived kinematic and free-piston Stirling engine concepts for stationary applications was explored. Automotive-derived engines offer cost advantages by providing a mature and developd engine technology base with downrating and parts commonality options for specific applications. Two engine sizes (30 and 400 kW), two Stirling engine configurations (kinematic and free-piston), and two output systems (crankshaft and hydraulic pump) were studied. The study includes the influences of using either hydrogen or helium as the working gas. The first kinematic configuration selects an existing Stirling engine design from an automotive application and adapts it to stationary requirements. A 50,000-hour life requirement was established by downrating the engine to 40 kW and reducing auxiliary loads. Efficiency improvements were gained by selective material and geometric variations and peak brake efficiency of 36.8 percent using helium gas was achieved. The second design was a four-cylinder, 400 kW engine, utilizing a new output drive system known as the z-crank, which provides lower friction losses and variable stroke power control. Three different material and working gas combinations were considered. Brake efficiency levels varied from 40.5 percent to 45.6 percent. A 37.5 kW single-cycle, free-piston hydraulic output design was generated by scaling one cylinder of the original automotive engine and mating it to a counterbalanced reciprocal hydraulic pump. Metallic diaphragms were utilized to transmit power.

A conceptual study of the potential for automotive-derived and free-piston Stirling engines in 30- to 400-kilowatt stationary power applications

Science.gov (United States)

Vatsky, A.; Chen, H. S.; Dineen, J.

1982-05-01

The technical feasibility of applying automotive-derived kinematic and free-piston Stirling engine concepts for stationary applications was explored. Automotive-derived engines offer cost advantages by providing a mature and developd engine technology base with downrating and parts commonality options for specific applications. Two engine sizes (30 and 400 kW), two Stirling engine configurations (kinematic and free-piston), and two output systems (crankshaft and hydraulic pump) were studied. The study includes the influences of using either hydrogen or helium as the working gas. The first kinematic configuration selects an existing Stirling engine design from an automotive application and adapts it to stationary requirements. A 50,000-hour life requirement was established by downrating the engine to 40 kW and reducing auxiliary loads. Efficiency improvements were gained by selective material and geometric variations and peak brake efficiency of 36.8 percent using helium gas was achieved. The second design was a four-cylinder, 400 kW engine, utilizing a new output drive system known as the z-crank, which provides lower friction losses and variable stroke power control. Three different material and working gas combinations were considered. Brake efficiency levels varied from 40.5 percent to 45.6 percent. A 37.5 kW single-cycle, free-piston hydraulic output design was generated by scaling one cylinder of the original automotive engine and mating it to a counterbalanced reciprocal hydraulic pump. Metallic diaphragms were utilized to transmit power.

Experimental Investigation of Piston Rings for Internal Combustion Engines

DEFF Research Database (Denmark)

Christiansen, Jens; Klit, Peder; Vølund, Anders

2007-01-01

One of the major prerequisites for calculating piston ring friction is a good description of the tribological situation. A very important condition for describing the frictional behavior of a piston ring correctly is knowledge about the amount of lubricant present. For piston rings the external...... forces are small compared to the rest of the acting forces the main design idea is to fix the piston, while the cylinder liner moves. This approach makes it simple to measure the parameters mentioned above by putting the instrumentation in the piston. The aim of this paper is describe the tribological...

Pistons and engine testing

CERN Document Server

GmbH, Mahle

2012-01-01

The ever-increasing demands placed on combustion engines are just as great when it comes to this centerpiece - the piston. Achieving less weight or friction, or even greater wear resistance, requires in-depth knowledge of the processes taking place inside the engine, suitable materials, and appropriate design and machining processes for pistons, including the necessary testing measures. It is no longer possible for professionals in automotive engineering to manage without specific know-how of this kind, whether they work in the field of design, development, testing, or maintenance. This techni

Isothermal sinusoidal analysis of balanced compound Vuilleumier heat pumps

International Nuclear Information System (INIS)

Finkelstein, T.

1992-01-01

This paper reports on Vuilleumier heat pumps with balanced compounding which have been under investigation for about fifteen years but have not yet reached the stage of commercial utilization. Previously published analytical treatment based upon isothermal treatment of the variable-volume spaces resulted in closed form solution of considerable complexity of the coupled differential equations but applied only to free piston machines. In contrast, the procedure presented here is based on previously demonstrated sinusoidal excursions of the reciprocators. It is of the same order of accuracy, but much more simple and usable. It was found that there is only negligible difference between the results of the present and the previous approach. Additionally, the treatment presented here is applicable to kinematic machines, as well as to free piston machines. For the latter design, an equation for the natural frequency is also derived. Ideal proportions and practical expressions for the energy streams are derived. Gas forces are plotted versus displacement and it is shown that they are equivalent to a linear spring, which is of importance for the concept of a free-piston design

Pump limiter experiment in the TFR tokamak

International Nuclear Information System (INIS)

Anon.

1987-01-01

Pump limiter experiments are carried out in the TFR Tokamak. The first TFR pump limiter is located in the outer part of the torus, its double-throat head is made of graphite tiles, the neutralizer plates are made of stainless steel, and it is pumped by a 3500 l s -1 titanium sublimation pump. The first attempts showed that the exhaust efficiency ε of this pump limiter was low (1.5% of the total plasma particle efflux). To improve on these results, a new limiter head with a single longer throat has been built. The particles were better trapped and the pumping achieved an important decrease of the recycling coefficient. Geometric features and also the highly non linear regime of pressure in the pump limiter as a function of the density at the entrance slot could explain the increase by a factor 3.5 of the exhaust efficiency (ε = 5%). Ion temperatures of the order of a few eV have been deduced from Doppler broadening measurements at the neutralizer plate of the pump limiter. (orig.)

History of heat pumps - Swiss contributions and international milestones

Energy Technology Data Exchange (ETDEWEB)

Zogg, M

2008-05-15

Compared to conventional boilers, heating by heat pumps cuts down fuel consumption and CO{sub 2} emissions to about 50%. Compared to electric resistance heating, the energy consumption is even reduced up to 80%. Therefore, the impressive market penetration growth of heat pumps will continue. Swiss pioneers were the first to realize functioning vapour recompression plants. The first European heat pumps were realized in Switzerland. To date it remains one of the heat pump champions. Swiss pioneering work in the development of borehole heat exchangers, sewage heat recovery, oil free piston compressors and turbo compressors is well known. The biggest heat pump ever built comes from Switzerland. Although there is a fairly comprehensive natural gas distribution grid, 75% of the new single-family homes built in Switzerland are currently heated by heat pumps. This paper presents some of the highlights of this success story focusing on Swiss developments and relating them to the international milestones. In order to indicate the direction in which the future development might go to, some recent Swiss research projects are presented as well. (author)

Pumping behavior of sputtering ion pump

Energy Technology Data Exchange (ETDEWEB)

Chou, T.S.; Bittner, J.; Schuchman, J.

1991-12-31

To optimize the design of a distributed ion pump (DIP) for the Superconducting X-Ray Lithography Source (SXLS) the stability of the rotating electron cloud at very high magnetic field beyond transition, must be re-examined. In this work the pumping speed and frequency spectrum of a DIP at various voltages (1 to 10 KV) and various magnetic fields (0.1 to 4 Tesla) are measured. Three cell diameters 10 mm, 5 mm and 2.5 mm, each 8 mm long, and with 3 or 4 mm gaps between anode and cathode are investigated. In this study both the titanium cathodes and the stainless steel anode plates are perforated with holes comparable in size to the anode cell diameters. Only the partially saturated pumping behavior is under investigation. The ultimate pressure and conditioning of the pump will be investigated at a later date when the stability criterion for the electron cloud is better understood.

Pumping behavior of sputtering ion pump

Energy Technology Data Exchange (ETDEWEB)

Chou, T.S.; Bittner, J.; Schuchman, J.

1991-01-01

To optimize the design of a distributed ion pump (DIP) for the Superconducting X-Ray Lithography Source (SXLS) the stability of the rotating electron cloud at very high magnetic field beyond transition, must be re-examined. In this work the pumping speed and frequency spectrum of a DIP at various voltages (1 to 10 KV) and various magnetic fields (0.1 to 4 Tesla) are measured. Three cell diameters 10 mm, 5 mm and 2.5 mm, each 8 mm long, and with 3 or 4 mm gaps between anode and cathode are investigated. In this study both the titanium cathodes and the stainless steel anode plates are perforated with holes comparable in size to the anode cell diameters. Only the partially saturated pumping behavior is under investigation. The ultimate pressure and conditioning of the pump will be investigated at a later date when the stability criterion for the electron cloud is better understood.

On the Influence of Piston and Cylinder Density in Tribodynamics of a Radial Piston Digital Fluid Power Displacement Motor

DEFF Research Database (Denmark)

Johansen, Per; Roemer, Daniel Beck; Andersen, Torben O.

2015-01-01

-stroke displacement simulations are used as basis for the parametric analysis. From the parametric analysis a change, in the minimum film thickness as function of piston and cylinder density, is shown for certain operating modes of the digital fluid power displacement motor. This indicate a need for careful....... In this paper the influence of the inertia term on the lubrication gaps of a radial piston motor are studied by a parametric analysis of the piston and cylinder density in a multibody tribodynamic simulation model. The motor is modeled as a digital fluid power displacement machine and a series of full...... assessment of the applicability, of the force balance condition, if it is used in multibody tribodynamic simulations of radial piston digital fluid power displacement motors....

A reciprocating liquid helium pump used for forced flow of supercritical helium

International Nuclear Information System (INIS)

Krafft, G.; Zahn, G.

1978-01-01

The performance of a small double acting piston pump for circulating helium in a closed heat transfer loop is described. The pump was manufactured by LINDE AG, Munich, West Germany. The measured flow rate of supercritical helium was about 17 gs -1 (500 lhr -1 ) with a differential pressure of Δp = 0.5 x 10 5 Nm -2 at a working pressure of p = 6 x 10 5 Nm -2 . At differential pressures beyond 0.5 x 10 5 Nm -2 the volumetric efficiency decreases. (author)

Development of velocity interferometer and its application to piston motion measurement in a compression tube of freepiston shock tube; Sokudo kanshokei no kaihatsu to sono jiyu piston shogekihakan no asshuku kannai no piston undo no keisoku eno oyo ni kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

Koremoto, K.; Hashimoto, T. [Tohoku University, Sendai (Japan); Takayama, K. [Tohoku University, Sendai (Japan). Inst. of Fluid Science; Ito, K [National Aerospace Laboratory, Tokyo (Japan)

1999-10-25

A free piston shock tunnel has been intensively used as a hypersonic flow ground test facility and its characteristics depend sensitively upon the piston motion in its compression tube. The continuous measurement of the piston motion in its compression tube was studied in an analogue facility in which a piston motion in a 50mm dia. and 2000mm long compression tube was measured continuously and accurately from its start to the collision with bumper section. To achieve it a velocity interferometer was developed particularly to measure the piston speed in it. Then piston motions were successfully measured and result agreed very well with numerical result. (author)

Gas-driven pump for ground-water samples

Science.gov (United States)

Signor, Donald C.

1978-01-01

Observation wells installed for artificial-recharge research and other wells used in different ground-water programs are frequently cased with small-diameter steel pipe. To obtain samples from these small-diameter wells in order to monitor water quality, and to calibrate solute-transport models, a small-diameter pump with unique operating characteristics is required that causes a minimum alternation of samples during field sampling. A small-diameter gas-driven pump was designed and built to obtain water samples from wells of two-inch diameter or larger. The pump is a double-piston type with the following characteristics: (1) The water sample is isolated from the operating gas, (2) no source of electricity is ncessary, (3) operation is continuous, (4) use of compressed gas is efficient, and (5) operation is reliable over extended periods of time. Principles of operation, actual operation techniques, gas-use analyses and operating experience are described. Complete working drawings and a component list are included. Recent modifications and pump construction for high-pressure applications also are described. (Woodard-USGS)

Double acting stirling engine piston ring

Science.gov (United States)

Howarth, Roy B.

1986-01-01

A piston ring design for a Stirling engine wherein the contact pressure between the piston and the cylinder is maintained at a uniform level, independent of engine conditions through a balancing of the pressure exerted upon the ring's surface and thereby allowing the contact pressure on the ring to be predetermined through the use of a preloaded expander ring.

A Fourier Approximation Method for the Multi-Pump Multi-Piston Power Take-Off System

NARCIS (Netherlands)

Wei, Yanji; Barradas Berglind, Jose de Jesus; Muhammad Zaki Almuzakki, M.; van Rooij, Marijn; Wang, Ruoqi; Jayawardhana, Bayu; Vakis, Antonis I.

2018-01-01

In this work, a frequency-domain method for the numerical solution of the nonlinear dynamics of a wave energy converter with a pumping system is presented. To this end, a finite Fourier series is used to describe the nonlinear force components, i.e., the pumping force. The dynamics of the buoy and

Free-piston reciprocating cryogenic expander utilizing phase controller

Science.gov (United States)

Cha, Jeongmin; Park, Jiho; Kim, Kyungjoong; Jeong, Sangkwon

2017-02-01

In a free-piston expander which eliminates mechanical linkages, a prescribed behaviour of the free-piston movement is the key to an expander performance. In this paper, we have proposed an idea of reducing complexity of the free-piston expander. It is to replace both multiple solenoid valves and reservoirs that are indispensable in a previous machine with a combination of a single orifice-reservoir assembly. It functions as a phase controller like that of a pulse tube refrigerator so that it generates time-delay of pressure variation between the warm-end and the reservoir resulting in the intended expansion of the cold-end volume down to the pre-set reservoir pressure. The modeling of this unique free-piston reciprocating expander utilizing phase controller is developed to understand and predict the performance of the new-type expander. Additionally, the operating parameters are analysed at the specified conditions to enable one to develop a more efficient free-piston type cryogenic expander.

Improvement of pump tubes for gas guns and shock tube drivers

Science.gov (United States)

Bogdanoff, D. W.

1990-01-01

In a pump tube, a gas is mechanically compressed, producing very high pressures and sound speeds. The intensely heated gas produced in such a tube can be used to drive light gas guns and shock tubes. Three concepts are presented that have the potential to allow substantial reductions in the size and mass of the pump tube to be achieved. The first concept involves the use of one or more diaphragms in the pump tube, thus replacing a single compression process by multiple, successive compressions. The second concept involves a radical reduction in the length-to-diameter ratio of the pump tube and the pump tube piston. The third concept involves shock heating of the working gas by high explosives in a cyclindrical geometry reusable device. Preliminary design analyses are performed on all three concepts and they appear to be quite feasible. Reductions in the length and mass of the pump tube by factors up to about 11 and about 7, respectively, are predicted, relative to a benchmark conventional pump tube.

On the validity range of piston theory

CSIR Research Space (South Africa)

Meijer, M-C

2015-06-01

Full Text Available The basis of linear piston theory in unsteady potential flow is used in this work to develop a quantitative treatment of the validity range of piston theory. In the limit of steady flow, velocity perturbations from Donov’s series expansion...

A review of free-piston engine history and applications

Energy Technology Data Exchange (ETDEWEB)

Mikalsen, R.; Roskilly, A.P. [School of Marine Science and Technology, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU (United Kingdom)

2007-10-15

This document reviews the history of free-piston internal combustion engines, from the air compressors and gas generators used in the mid-20th century through to recent free-piston hydraulic engines and linear electric generators. Unique features of the free-piston engine are presented and their effects on engine operation are discussed, along with potential advantages and disadvantages compared to conventional engines. The paper focuses mainly on developed engines where operational data has been reported. Finally, the potential of the free-piston engine is evaluated and the most promising designs identified. (author)

Piston membrane pumps for slurries transport; Kolbenmembranpumpen fuer den Schlammtransport

Energy Technology Data Exchange (ETDEWEB)

Wiechmann, F. [Abel GmbH und Co. KG, Buechen (Germany)

2006-03-15

As raw materials prices are rising, ore and coal mines in remote parts of the world have become profitable. Local infrastructures in these regions are not comparable with Europe. There are no rods or railways, and pipelines must be constructed parallel to rivers through deserts, mountains and rainforests. As a rule, pipelines do not follow favourable geological conditions but are constructed along the shortest possible rout to the nearest port or the nearest processing plant. Slurries are transported by pumping. (orig.)

Gas action effect of free piston Stirling engine

International Nuclear Information System (INIS)

Mou, Jian; Li, Wei; Li, Jinze; Hong, Guotong

2016-01-01

Highlights: • The gas action effect is analyzed by the method of rotation vector decomposition. • Gas force can be decomposed into motivation force and spring or inertia force. • The optimal phase angles of displacements to pressure wave have been found. - Abstract: Gas action effect of free piston Stirling engine (FPSE) is very important to solve the key problem of start-up and find the way to increase its efficiency. The gas force is a key force to free FPSE. In this paper, the gas action effect has been analyzed by the method of rotation vector decomposition. It is found that the gas forces of piston and displacer can be decomposed into two forces, one component acts as motivation force resisting the damping force to output power, the other acts as spring force or inertia force according to the phase angle of pressure wave to displacements of the displacer and piston. Only when the motivation components of both piston and displacer resist their damping forces, will the FPSE be start-up and work stably. And only when the spring force is approximately equal to inertia force of piston, will the piston need the smallest gas spring force and nearly all the gas force be put for the alternator, meanwhile the engine outputs the maximum work. In the perfect condition, the optimal phase angle of the reciprocating movements of the displacer and piston ahead of the pressure wave are 180° and 90° respectively. The analyses above are verified by a series of experiments on a FPSE designed by our laboratory.

Test results of distributed ion pump designs for the PEP-II Asymmetric B-Factory collider

Energy Technology Data Exchange (ETDEWEB)

Calderon, M.; Holdener, F.; Peterson, D. [Lawrence Livermore National Lab., CA (United States)] [and others

1994-07-01

The testing facility measurement methods and results of prototype distributed ion pump (DIP) designs for the PEP-II B-Factory High Energy Ring are presented. Two basic designs with 5- or 7-anode plates were tested at LLNL with penning cell sizes of 15, 18, and 21 mm. Direct comparison of 5- and 7-plate anodes with 18 mm holes shows increased pumping speed with the 7-plate design. The 5-plate, 18 mm and 7-plate, 15 mm designs both gave an average pumping speed of 135 1/s/m at 1 {times} 10{sup {minus}8} Torr nitrogen base pressure in a varying 0.18 T peak B-field. Comparison of the three hole sizes indicates that cells smaller than the 15 mm tested can be efficiently used to obtain higher pumping speeds for the same anode plate sizes used.

Test results of distributed ion pump designs for the PEP-II Asymmetric B-Factory collider

International Nuclear Information System (INIS)

Calderon, M.; Holdener, F.; Peterson, D.

1994-07-01

The testing facility measurement methods and results of prototype distributed ion pump (DIP) designs for the PEP-II B-Factory High Energy Ring are presented. Two basic designs with 5- or 7-anode plates were tested at LLNL with penning cell sizes of 15, 18, and 21 mm. Direct comparison of 5- and 7-plate anodes with 18 mm holes shows increased pumping speed with the 7-plate design. The 5-plate, 18 mm and 7-plate, 15 mm designs both gave an average pumping speed of 135 1/s/m at 1 x 10 -8 Torr nitrogen base pressure in a varying 0.18 T peak B-field. Comparison of the three hole sizes indicates that cells smaller than the 15 mm tested can be efficiently used to obtain higher pumping speeds for the same anode plate sizes used

Instantaneous heat flux flowing into piston top-land surface of D.I. diesel engine; DI diesel kikan no piston top land bu eno shunji netsuryusoku

Energy Technology Data Exchange (ETDEWEB)

Taguma, M [Zexel Corp., Tokyo (Japan); Inui, M; Enomoto, Y; Hagihara, Y [Musashi Institute of Technology, Tokyo (Japan); Koyama, T [Mitsubishi Motors Co., Tokyo (Japan)

1997-10-01

The thermal loads of the piston top-land surface in D.I. diesel engine during actual operation is not cleared. The authors fixed thin film thermocouples in the top-land center of a standard piston, and measured the instantaneous heat fluxes in that place. As a result, the authors made clear the thermal loads of the piston top-land surface in a cycle, and confirmed presence of the flame inflow to the piston top-land center. In addition, the authors made clear the thermal loads of the piston top-land surface in EGR operation. 4 refs., 8 figs.

Gas-lift pumps for flowing and purifying molten silicon

Science.gov (United States)

Kellerman, Peter L.; Carlson, Frederick

2016-02-23

The embodiments herein relate to a sheet production apparatus. A vessel is configured to hold a melt of a material and a cooling plate is disposed proximate the melt. This cooling plate configured to form a sheet of the material on the melt. A pump is used. In one instance, this pump includes a gas source and a conduit in fluid communication with the gas source. In another instance, this pump injects a gas into a melt. The gas can raise the melt or provide momentum to the melt.

The control of a free-piston engine generator. Part 2: Engine dynamics and piston motion control

Energy Technology Data Exchange (ETDEWEB)

Mikalsen, R.; Roskilly, A.P. [Sir Joseph Swan Institute for Energy Research, Newcastle University, Newcastle upon Tyne, NE1 7RU England (United Kingdom)

2010-04-15

Free-piston engines are under investigation by a number of research groups due to potential fuel efficiency and exhaust emissions advantages over conventional technology. The main challenge with such engines is the control of the piston motion, and this has not yet been fully resolved for all types of free-piston engines. This paper builds on the fundamental investigations presented in the accompanying paper and investigates the dynamics of the engine and the feasibility of classical control approaches. The response of the engine to rapid load changes are investigated using decentralised PID, PDF and disturbance feedforward. It is found that the engine is sensitive to rapid load changes but that in constant power applications standard control techniques provide satisfactory performance. The influence of cycle-to-cycle variations in the combustion process are investigated, but not found to be critical for engine operation. (author)

Computational Modelling of Piston Ring Dynamics in 3D

Directory of Open Access Journals (Sweden)

Dlugoš Jozef

2014-12-01

Full Text Available Advanced computational models of a piston assembly based on the level of virtual prototypes require a detailed description of piston ring behaviour. Considering these requirements, the piston rings operate in regimes that cannot, in general, be simplified into an axisymmetric model. The piston and the cylinder liner do not have a perfect round shape, mainly due to machining tolerances and external thermo-mechanical loads. If the ring cannot follow the liner deformations, a local loss of contact occurs resulting in blow-by and increased consumption of lubricant oil in the engine. Current computational models are unable to implement such effects. The paper focuses on the development of a flexible 3D piston ring model based on the Timoshenko beam theory using the multibody system (MBS. The MBS model is compared to the finite element method (FEM solution.

The influence oil film lubrication of the piston-cylinder dynamic

Directory of Open Access Journals (Sweden)

Adriana Tokar

2008-10-01

Full Text Available An analytical study of the dynamics of a piston in a reciprocating engine was conducted. The equation of Reynolds and moving of piston are derived. The analysis, which incorporates a hydrodynamic lubrication model, was applied to M501 diesel engine. The results of this study indicate that piston dynamics were found to be sensitive to piston-cylinder bore clearance, location of the wrist pin and lubricant viscosity, underscoring their importance in engine design.

Heat pump used in milk pasteurization: an energy analysis

Energy Technology Data Exchange (ETDEWEB)

Ozyurt, O.; Comakli, O.; Yilmaz, M. [Ataturk Univ., Erzurum (Turkey). Dept. of Mechanical Engineering; Karsli, S. [Ataturk Univ., Erzurum (Turkey). Vocational School of Higher Education

2004-07-01

This study investigates the applicability of heat pumps to milk pasteurization for cheese production and to compare the results with classical pasteurization systems. The experiments are conducted in a liquid-to-liquid vapour compression heat pump system and a milk-to-milk plate heat exchanger is used as an economizer. The experiments are also conducted in a double jacket boiler system and a plate pasteurization system, which are classical milk pasteurization systems. The results for the three systems are compared and the advantages/disadvantages of using heat pump for milk pasteurization instead of classical systems are determined. It is found that the heat pump consumes less energy than the other two classical systems. (Author)

Engine including a piston member having a high top ring groove

Energy Technology Data Exchange (ETDEWEB)

Weber, R.L.; Kamman, K.R.; Ballheimer, B.; Shoup, S.G.

1990-07-17

This patent describes an improvement in an engine. It is of the type having a block defining an upper bore, a cylinder liner located in the block bore and defining a piston bore, a cylinder head connected to the block, and a piston assembly including a steel piston member disposed for reciprocation in the piston bore.

Piston surface heat transfer during combustion in large marine diesel engines

DEFF Research Database (Denmark)

Jensen, Michael Vincent; Walther, Jens Honore

2010-01-01

In the design process of large marine diesel engines information on the maximum heat load on the piston surface experienced during the engine cycle is an important parameter. The peak heat load occurs during combustion when hot combustion products impinge on the piston surface. Although the maximum...... heat load is only present for a short time of the total engine cycle, it is a severe thermal load on the piston surface. At the same time, cooling of the piston crown is generally more complicated than cooling of the other components of the combustion chamber. This can occasionally cause problems...... with burning off piston surface material. In this work the peak heat load on the piston surface of large marine diesel engines during combustion was investigated. Measurements of the instantaneous surface temperature and surface heat flux on pistons in large marine engines are difficult due to expensive...

Reduction of HCCI combustion noise through piston crown design

DEFF Research Database (Denmark)

Pedersen, Troels Dyhr; Schramm, Jesper

2010-01-01

. The largest and most consistent reduction in noise level was however achieved with a diesel bowl type piston. The increased surface area as well as the larger crevice volumes of the experimental piston crowns generally resulted in lower IMEP than the flat piston. While the crevice volumes can be reduced...... away from the engine. The experiments were conducted in a diesel engine that was run in HCCI combustion mode with a fixed quantity of DME as fuel. The results show that combustion knock is effectively suppressed by limiting the size of the volume in which the combustion occurs. Splitting...... the compression volume into four smaller volumes placed between the perimeter of the piston and the cylinder liner increased the noise to a higher level than that generated with a flat piston crown. This was due to resonance between the four volumes. Using eight volumes instead decreased the noise. The noise...

New monobolt piston design for large engines; Neues Monobolt-Kolbendesign fuer Grossmotoren

Energy Technology Data Exchange (ETDEWEB)

Estrum, T.; Kortas, J.; Geissler, C. [Mahle GmbH, Markgroeningen (Germany). Profitcenter Grossmotorenkomponenten

2008-07-15

High-load pistons for modern, powerful large diesel and gas engines require increasingly more compact and lightweight designs. Due to the low installation height, less room remains for the required screw length in traditional large-bore piston designs, where the piston crown is screwed to the piston skirt. With the new development of the compact monobolt piston design, the Mahle Large Engine Components Profit Center succeeded in satisfying the requirements for an extremely low installation height of a composite piston, while allowing high mechanical and thermal loads. (orig.)

Insulin Pump Malfunction During Hospitalization: Two Case Reports.

Science.gov (United States)

Faulds, Eileen R; Wyne, Kathleen L; Buschur, Elizabeth O; McDaniel, Jodi; Dungan, Kathleen

2016-06-01

Insulin pump malfunctions and failures continue to occur; however, more severe malfunctions such as the "runaway pump" phenomenon are rarely reported. This article describes two cases of pump malfunction in which pump users appear to have received an unsolicited bolus of insulin resulting in severe episodes of hypoglycemia during hospitalization. Both cases of insulin pump malfunction occurred in the inpatient setting at a large academic medical center in the United States. An analysis of the corresponding insulin pump downloads was performed. The Food and Drug Administration's (FDA's) Manufacturer and User Facility Device Experience (MAUDE) database was searched for similar cases involving Medtronic (Northridge, CA) insulin pumps using the terms "pump," "infusion," "insulin AND malfunction AND Medtronic." The two cases described show remarkable similarities, each demonstrating a severe hypoglycemic event preceded by an infusion site change followed by an alarm. In both cases a rapid spraying of insulin was reported. The insulin pump downloads validated much of the patients' and medical staff's descriptions of events. The FDA's MAUDE database search revealed 425 cases meeting our search term criteria. All cases were reviewed. Seven cases were identified involving independent movement of the reservoir piston. The cases detailed are the first to describe an insulin pump malfunction of this nature in the hospital setting involving unsolicited insulin boluses leading to severe hypoglycemia. The cases are particularly compelling in that they were witnessed by medical personnel. Providers and patients should receive instruction education on the recognition and management of insulin pump malfunction.

Development and application of a double-piston configured, total-liquid ventilatory support device.

Science.gov (United States)

Meinhardt, J P; Quintel, M; Hirschl, R B

2000-05-01

Perfluorocarbon liquid ventilation has been shown to enhance pulmonary mechanics and gas exchange in the setting of respiratory failure. To optimize the total liquid ventilation process, we developed a volume-limited, time-cycled liquid ventilatory support, consisting of an electrically actuated, microprocessor-controlled, double-cylinder, piston pump with two separate limbs for active inspiration and expiration. Prospective, controlled, animal laboratory study, involving sequential application of conventional gas ventilation, partial ventilation (PLV), and total liquid ventilation (TLV). Research facility at a university medical center. A total of 12 normal adult New Zealand rabbits weighing 3.25+/-0.1 kg. Anesthestized rabbits were supported with gas ventilation for 30 mins (respiratory rate, 20 cycles/min; peak inspiratory pressure, 15 cm H2O; end-expiratory pressure, 5 cm H2O), then PLV was established with perflubron (12 mL/kg). After 15 mins, TLV was instituted (tidal volume, 18 mL/kg; respiratory rate, 7 cycles/min; inspiratory/expiratory ratio, 1:2 cycles/min). After 4 hrs of TLV, PLV was re-established. Of 12 animals, nine survived the 4-hr TLV period. During TLV, mean values +/- SEM were as follows: PaO2, 363+/-30 torr; PaCO2, 39+/-1.5 torr; pH, 7.39+/-0.01; static peak inspiratory pressure, 13.2+/-0.2 cm H2O; static endexpiratory pressure, 5.5+/-0.1 cm H2O. No significant changes were observed. When compared with gas ventilation and PLV, significant increases occurred in mean arterial pressure (62.4+/-3.5 torr vs. 74.0+/-1.2 torr) and central venous pressure (5.6+/-0.7 cm H2O vs. 7.8+/-0.2 cm H2O) (p piston pumps with active expiration. Considering the enhanced flow profiles, this device configuration provides advantages over others.

Development of a proof of concept low temperature 4He Superfluid Magnetic Pump

Science.gov (United States)

Jahromi, Amir E.; Miller, Franklin K.

2017-03-01

We describe the development and experimental results of a proof of concept Superfluid Magnetic Pump in this work. This novel low temperature, no moving part pump can replace the existing bellows-piston driven 4He or 3He-4He mixture compressor/circulators used in various sub Kelvin refrigeration systems such as dilution, Superfluid pulse tube, Stirling, or active magnetic regenerative refrigerators. Due to the superior thermal transport properties of sub-Lambda 4He this pump can also be used as a simple circulator to distribute cooling over large surface areas. Our pump was experimentally shown to produce a maximum flow rate of 440 mg/s (averaged over cycle), 665 mg/s (peak) and produced a maximum pressure difference of 2323 Pa using only the more common isotope of helium, 4He. This pump worked in an ;ideal; thermodynamic state: The experimental results matched with the theoretical values predicted by a computer model. Pump curves were developed to map the performance of this pump. This successful demonstration will enable this novel pump to be implemented in suitable sub Kelvin refrigeration systems.

Three-dimensional Casimir piston for massive scalar fields

International Nuclear Information System (INIS)

Lim, S.C.; Teo, L.P.

2009-01-01

We consider Casimir force acting on a three-dimensional rectangular piston due to a massive scalar field subject to periodic, Dirichlet and Neumann boundary conditions. Exponential cut-off method is used to derive the Casimir energy. It is shown that the divergent terms do not contribute to the Casimir force acting on the piston, thus render a finite well-defined Casimir force acting on the piston. Explicit expressions for the total Casimir force acting on the piston is derived, which show that the Casimir force is always attractive for all the different boundary conditions considered. As a function of a - the distance from the piston to the opposite wall, it is found that the magnitude of the Casimir force behaves like 1/a 4 when a→0 + and decays exponentially when a→∞. Moreover, the magnitude of the Casimir force is always a decreasing function of a. On the other hand, passing from massless to massive, we find that the effect of the mass is insignificant when a is small, but the magnitude of the force is decreased for large a in the massive case.

Loss terms in free-piston Stirling engine models

Science.gov (United States)

Gordon, Lloyd B.

1992-01-01

Various models for free piston Stirling engines are reviewed. Initial models were developed primarily for design purposes and to predict operating parameters, especially efficiency. More recently, however, such models have been used to predict engine stability. Free piston Stirling engines have no kinematic constraints and stability may not only be sensitive to the load, but also to various nonlinear loss and spring constraints. The present understanding is reviewed of various loss mechanisms for free piston Stirling engines and how they have been incorporated into engine models is discussed.

Quasi-open loop hydraulic ram incremental actuator with power conserving properties

International Nuclear Information System (INIS)

Raymond, E.T.; Robinson, C.W.

1982-01-01

An electric stepping motor, operated by command signals from a computer or a microprocessor, rotates a rotary control member of a distributor valve, for sequencing hydraulic pressure and hence flow to the cylinders of an axial piston hydraulic machine. A group of the cylinders are subjected to pressure and flow and the remaining cylinders are vented to a return line. Rotation of the rotary control valve member sequences pressurization by progressively adding a cylinder to the forward edge to the pressurized group and removing a cylinder from the trailing edge of the pressurized group. The double ended pistons of each new pressurized group function to drive a wobble plate into a new position of equilibrium and then hold it in such position until another change in the makeup of the pressurized group. These pistons also displace hydraulic fluid from the opposite cylinder head which serves as the output of a pumping element. An increment of displacement of the wobble plate occurs in direct response to each command pulse that is received by the stepping motor. Wobble plate displacement drives the rotary valve of the hydraulic power transfer unit, causing it to transfer hydraulic fluid from a first expansible chamber on one side of a piston in a hydraulic ram to a second expansible chamber on the opposite side of the piston. Reverse drive of the hydraulic power transfer unit reverses the direction of transfer of hydraulic fluid between the two expansible chambers

Coupled hydrodynamic-structure analysis of piston motion in reciprocating compressors

International Nuclear Information System (INIS)

Moon, Seung Ju; Cho, Jin Rae; Ryu, Sung Hyon

2003-01-01

The piston slap phenomenon is one of the major noise source of reciprocating compressors used in household electric appliances. In response to public demand, strict regulations are increasingly being imposed on the allowable noise level which is caused mostly by household electric appliances. In this paper, the dynamic behavior of suction and discharge valves are analytically calculated and the lubricant behavior between piston and cylinder are investigated using two-dimensional Reynolds equation. And the piston slap caused by the piston secondary motion is investigated by the finite element method

Experimental performance of a piston expander in a small- scale organic Rankine cycle

Science.gov (United States)

Oudkerk, J. F.; Dickes, R.; Dumont, O.; Lemort, V.

2015-08-01

Volumetric expanders are suitable for more and more applications in the field of micro- and small-scale power system as waster heat recovery or solar energy. This paper present an experimental study carried out on a swatch-plate piston expander. The expander was integrated into an ORC test-bench using R245fa. The performances are evaluated in term of isentropic efficiency and filling factor. The maximum efficiency and power reached are respectively 53% and 2 kW. Inside cylinder pressure measurements allow to compute mechanical efficiency and drown P-V diagram. A semi-empirical simulation model is then proposed, calibrated and used to analyse the different sources of losses.

A One-Square-Millimeter Compact Hollow Structure for Microfluidic Pumping on an All-Glass Chip

Directory of Open Access Journals (Sweden)

Xing Yue (Larry Peng

2016-04-01

Full Text Available A micro surface tension pump is a new type of low-cost, built-in, all-glass, microfluidic pump on a glass microchip fabricated by one-step glass etching. However, geometric minimization and optimization for practical use are challenging. Here, we report a one-square-millimeter, built-in, all-glass pump controlled by two-way digital gas pressure. The pump consists simply of two joint chambers and a piston between two gas control channels. It does not require pre-perfusion for initialization, and can immediately begin to run when a liquid enters its inlet channel. It is also more reliable than conventional micro pumps for practical use due to its ability to restart after the formation of a blocking bubble, which can serve as a valuable troubleshooting procedure. Its volumetric pump output was 0.5–0.7 nL·s−1 under a pump head pressure of 300 Pa.

Fluorocarbon seal replaces metal piston ring in low density gas environment

Science.gov (United States)

Morath, W. D.; Morgan, N. E.

1967-01-01

Reinforced fluorocarbon cupseal, which provides an integral lip-type seal, replaces the metal piston rings in piston-cylinder configurations used in the compression of low density gases. The fluorocarbon seal may be used as cryogenic compressor piston seals.

Tribological Performance of Different Geometries of Piston Rings in Marine Diesel Engines

DEFF Research Database (Denmark)

Imran, Tajammal; Klit, Peder; Felter, Christian

Friction in the piston ring package (piston, piston rings and liner) is a major source of power consumption in two stroke marine diesel engines. It is well-known that a typical piston ring operates under full separation in the mid-part of the stroke, and in the mixed lubrication regime at the dead...

Fluid powered linear piston motor with harmonic coupling

Science.gov (United States)

Raymond, David W.

2016-09-20

A motor is disclosed that includes a module assembly including a piston that is axially cycled. The piston axial motion is coupled to torque couplers that convert the axial motion into rotary motion. The torque couplers are coupled to a rotor to rotate the rotor.

Numerical simulation and design optimization of an electrohydrodynamic pump for dielectric liquids

International Nuclear Information System (INIS)

Fernandes, D.V.; Suh, Y.K.

2016-01-01

Highlight: • We firstly demonstrated that optimized set of parameters exists in the design of an electrohydrodynamic(EHD) pump. • We applied recently developed techniques of optimization to the EHD pump composed of a pair of flat plates and one circular cylinder. • Our work serves as driving knowledge for the research area on EHD pumping. - Abstract: With an ever increasing demand for more effective heat sinks, liquid based electronic cooling has become a new prospect in the field. The present study introduces an electrohydrodynamic (EHD) pump with a simple design for dielectric liquids which have potential applications for electronic cooling. The pump consists of an eccentrically sandwiched wire electrode placed at the horizontal centerline between two parallel flat-plate electrodes. The EHD flow of dielectric liquid induced by the space charge generated due to the Onsager effect was obtained by the numerical solution of the Poisson–Nernst–Planck equations for ion transport and the Navier–Stokes equations for fluid flow. Good agreement obtained in the comparison of the numerical and the experimental results of velocity for the centrally sandwiched wire electrode case confirmed the validity of the numerical results. For a fixed voltage, the pump flow rate depends on the eccentricity of the wire electrode with respect to the plate electrodes and also with the electrode dimensions. By using the Taguchi method an optimum design for the EHD pump is obtained considering the wire electrode diameter, the flat plate electrode length and the eccentricity (the horizontal distance between the centers of wire and flat-plate electrodes) as the design parameters for fixed channel dimensions.

Thermally Actuated Hydraulic Pumps

Science.gov (United States)

Jones, Jack; Ross, Ronald; Chao, Yi

2008-01-01

Thermally actuated hydraulic pumps have been proposed for diverse applications in which direct electrical or mechanical actuation is undesirable and the relative slowness of thermal actuation can be tolerated. The proposed pumps would not contain any sliding (wearing) parts in their compressors and, hence, could have long operational lifetimes. The basic principle of a pump according to the proposal is to utilize the thermal expansion and contraction of a wax or other phase-change material in contact with a hydraulic fluid in a rigid chamber. Heating the chamber and its contents from below to above the melting temperature of the phase-change material would cause the material to expand significantly, thus causing a substantial increase in hydraulic pressure and/or a substantial displacement of hydraulic fluid out of the chamber. Similarly, cooling the chamber and its contents from above to below the melting temperature of the phase-change material would cause the material to contract significantly, thus causing a substantial decrease in hydraulic pressure and/or a substantial displacement of hydraulic fluid into the chamber. The displacement of the hydraulic fluid could be used to drive a piston. The figure illustrates a simple example of a hydraulic jack driven by a thermally actuated hydraulic pump. The pump chamber would be a cylinder containing encapsulated wax pellets and containing radial fins to facilitate transfer of heat to and from the wax. The plastic encapsulation would serve as an oil/wax barrier and the remaining interior space could be filled with hydraulic oil. A filter would retain the encapsulated wax particles in the pump chamber while allowing the hydraulic oil to flow into and out of the chamber. In one important class of potential applications, thermally actuated hydraulic pumps, exploiting vertical ocean temperature gradients for heating and cooling as needed, would be used to vary hydraulic pressures to control buoyancy in undersea research

THE COURSE IN TESTING THE WEARING OUT OF MUD PUMPS PARTS

Directory of Open Access Journals (Sweden)

Davorin Matanović

1989-12-01

Full Text Available Piston and cylinder are such parts in the mud pumps which cause the greatest expences due to the work stoppage of drilling rig. To reduce so caused expences it is necessary to produce spare parts of better quality. In determining the abrasion wear resistance for chosen materials, so called dry sand/rubber wheel abrasion test as an ASTM standard has been used (the paper is published in Croatian.

Piston ring lubrication and hydrocarbon emissions from internal combustion engines

Energy Technology Data Exchange (ETDEWEB)

Froelund, K.

1997-11-01

Is it the intention with this project to improve the existing hydrocarbon emission model at the Institute by combining it with a model for predicting the piston ring lubrication. The piston ring lubrication model should be experimentally verified to ensure the validity of the model. The following items were the objectives of the current study: Develop a piston ring lubrication model. This implies the development of a ring-pack gas flow model; Examine the response of the piston ring lubrication model to changing engineer conditions. Especially, it would be interesting to look at the engine warm-up phase since this is the phase where the engine-out emissions are highest and where the commonly used three way catalyst is not capable of converting the engine-out emissions, thereby leading the engine-out emissions directly out in to the environment with the exhaust gases; In order to verify the piston ring lubrication model the lubricant distribution on the cylinder liner should be investigated experimentally. Here again it would be of great interesting to look at the engine warm-up phase; The piston ring lubrication model should be adjusted for application together with the new hydrocarbon emission model for SI-engines at the Institute in order to increase the accuracy of the latter; The piston ring lubrication model could be used for describing the transport of PAH`s in diesel engines. (EG)

Analytical and experimental investigation of ringless-piston concept. Interim report, September 1986-December 1987

Energy Technology Data Exchange (ETDEWEB)

Dickey, D.W.; Wood, C.D.

1987-12-01

The purpose of this project was to analytically and experimentally investigate the concept of a ringless-piston internal-combustion engine. A joint objective was to design, build, and test a ringless piston to improve ringless-piston engine performance. A computer model was developed to predict ringed and ringless-piston engine performance. Experimental performance data were then collected by operating a small, liquid-cooled, two-stroke gasoline engine with and without the piston ring on the stock aluminum and Southwest Research Institute prototype steel piston. The experimental performance data were then compared with the results of the computer model. The results showed that a piston engine can operate without piston rings.

Analytical and experimental investigation of ringless-piston concept. Final report, September 1986-November 1987

Energy Technology Data Exchange (ETDEWEB)

Dickey, D.W.; Wood, C.D.

1988-03-01

The purpose of this project was to analytically and experimentally investigate the concept of a ringless-piston internal combustion engine. A joint objective was to design, build, and test a ringless piston to improve ringless piston engine performance. A computer model was developed to predict ringed and ringless piston engine performance. Experimental performance data were then collected by operating a small, liquid-cooled, two-stroke gasoline engine with and without the piston ring on the stock aluminum and Southwest Research Institute prototype steel piston. The experimental performance data were then compared with the results of the computer model. The results showed that a piston engine can operate without piston rings. Ringless-piston engine power and efficiency were found to be defined by the expression C/NBS, where C = piston-to-bore diametrical clearance, N = engine speed in rpm, B = engine bore, and S = engine stroke. There was good agreement between predicted and measured performance reperformance can be improved by using piston and liner materials that have similar coefficients of thermal expansion.

Ensuring Steady Operation of Free-Piston Generator

OpenAIRE

Pavel Nemecek

2006-01-01

This paper describes Free-Piston Generator (FPG) model and its control for achieving steady operation. A FPG is a special type of combustion engine representing a new approach concerning the conversion of the chemical energy of hydrocarbon fuel into electrical energy. Unlike conventional engines, this type of engine does not use a crankshaft, and generates electric energy directly by a linear movement of pistons.

Ensuring Steady Operation of Free-Piston Generator

Directory of Open Access Journals (Sweden)

Pavel Nemecek

2006-02-01

Full Text Available This paper describes Free-Piston Generator (FPG model and its control for achieving steady operation. A FPG is a special type of combustion engine representing a new approach concerning the conversion of the chemical energy of hydrocarbon fuel into electrical energy. Unlike conventional engines, this type of engine does not use a crankshaft, and generates electric energy directly by a linear movement of pistons.

Root-Contact/Pressure-Plate Assembly For Hydroponic System

Science.gov (United States)

Morris, Carlton E.; Loretan, Philip A.; Bonsi, Conrad K.; Hill, Walter A.

1994-01-01

Hydroponic system includes growth channels equipped with rootcontact/pressure-plate assemblies. Pump and associated plumbing circulate nutrient liquid from reservoir, along bottom of growth channels, and back to reservoir. Root-contact/pressure-plate assembly in each growth channel stimulates growth of roots by applying mild contact pressure. Flat plate and plate connectors, together constitute pressure plate, free to move upward to accommodate growth of roots. System used for growing sweetpotatoes and possibly other tuber and root crops.

Simulations geometric structures of the stepped profile bearing surface of the piston

Directory of Open Access Journals (Sweden)

Wroblewski Emil

2017-01-01

Full Text Available The main node piston-pin-piston rings are most responsible for the formation of mechanical losses. It is advisable to reduce friction losses in the piston-cylinder group lead to an increase in the overall efficiency of the engine and thus reduce the fuel consumption. The method to reduce the area covered by the oil film is a modification of the bearing surface of the piston by adjusting the profile. In this paper the results of simulation for the stepped microgeometry piston bearing surface are presented.

Experimental Piston Ring Tribology for Marine Diesel Engines

DEFF Research Database (Denmark)

Klit, Peder; Vølund, Anders

2008-01-01

A very important condition for describing the frictional behavior of a piston ring correctly is knowledge about the amount of lubricant present. It is often assumed that piston rings operate under fully flooded conditions, but this is not the case in real life operation. In large two-stroke engin...

RE-1000 free-piston Stirling engine update

Science.gov (United States)

Schreiber, J. G.

1985-01-01

A free piston Stirling engine was tested. The tests performed over the past several years on the single cylinder engine were designed to investigate the dynamics of a free piston Stirling engine. The data are intended to be used primarily for computer code validation. The tests designed to investigate the sensitivity of the engine performance to variations in working space pressure, heater and cooler temperatures, regenerator porosity, power piston mass and displacer dynamics were completed. In addition, some data were recorded with alternate working fluids. A novel resonant balance system for the engine was also tested. Some preliminary test results of the tests performed are presented along with an outline of future tests to be run with the engine coupled to a hydraulic output unit. A description of the hydraulic output unit is given.

The control of a free-piston engine generator. Part 1: Fundamental analyses

Energy Technology Data Exchange (ETDEWEB)

Mikalsen, R.; Roskilly, A.P. [Sir Joseph Swan Institute for Energy Research, Newcastle University, Newcastle upon Tyne, NE1 7RU, England (United Kingdom)

2010-04-15

Free-piston engines are under investigation by a number of research groups due to potential fuel efficiency and exhaust emissions advantages over conventional technology. The main challenge with such engines is the control of the piston motion, and this has not yet been fully resolved for all types of free-piston engines. This paper discusses the basic features of a single piston free-piston engine generator under development at Newcastle University and investigates engine control issues using a full-cycle simulation model. Control variables and disturbances are identified, and a control strategy is proposed. It is found that the control of the free-piston engine is a challenge, but that the proposed control strategy is feasible. Engine speed control does, however, represent a challenge in the current design. (author)

Free piston space Stirling technology program

Science.gov (United States)

Dochat, G. R.; Dhar, M.

1989-01-01

MTI recently completed an initial technology feasibility program for NASA by designing, fabricating and testing a space power demonstrator engine (SPDE). This program, which confirms the potential of free-piston Stirling engines, provided the major impetus to initiate a free-piston Stirling space engine (SSE) technology program. The accomplishments of the SPDE program are reviewed, and an overview of the SSE technology program and technical status to date is provided. It is shown that progress in both programs continues to justify its potential for either nuclear or solar space power missions.

Dynamics of a massive piston in an ideal gas

International Nuclear Information System (INIS)

Chernov, N I; Lebowitz, J L; Sinai, Yakov G

2002-01-01

This survey is a study of a dynamical system consisting of a massive piston in a cubic container of large size L filled with an ideal gas. The piston has mass M∼L 2 and undergoes elastic collisions with N∼L 3 non-interacting gas particles of mass m=1. It is found that under suitable initial conditions there is a scaling regime with time and space scaled by L in which the motion of the piston and the one-particle distribution of the gas satisfy autonomous coupled equations (hydrodynamic equations) such that in the limit L→∞ the mechanical trajectory of the piston converges in probability to the solution of the hydrodynamic equations for a certain period of time. There is also a heuristic discussion of the dynamics of the system on longer intervals of time

The Casimir effect for pistons with transmittal boundary conditions

Science.gov (United States)

Fucci, Guglielmo

2017-11-01

This work focuses on the analysis of the Casimir effect for pistons subject to transmittal boundary conditions. In particular we consider, as piston configuration, a direct product manifold of the type I × N where I is a closed interval of the real line and N is a smooth compact Riemannian manifold. By utilizing the spectral zeta function regularization technique, we compute the Casimir energy of the system and the Casimir force acting on the piston. Explicit results for the force are provided when the manifold N is a d-dimensional sphere.

Performance simulation of a spark ignited free-piston engine generator

Energy Technology Data Exchange (ETDEWEB)

Mikalsen, R.; Roskilly, A.P. [Sir Joseph Swan Institute for Energy Research, University of Newcastle upon Tyne, Newcastle upon Tyne, NE1 7RU (United Kingdom)

2008-10-15

Free-piston engines are under investigation by a number of research groups worldwide due to potential fuel efficiency and engine emissions advantages. The free-piston engine generator, in which a linear electric generator is fixed to the mover to produce electric power, has been proposed as an alternative prime mover for hybrid-electric vehicles. This paper investigates the performance of a spark ignited free-piston engine generator and compares it to a conventional engine using a computational fluid dynamics simulation model. The particular operating characteristics of the free-piston engine were not found to give noticeable performance advantages, and it is concluded that the main potential of this technology lies in the simplicity and flexibility of the concept. (author)

Motion characteristic of a free piston linear engine

Energy Technology Data Exchange (ETDEWEB)

Xiao, Jin; Li, Qingfeng; Huang, Zhen [Key Laboratory for Power Machinery and Engineering of Ministry of Education, Shanghai Jiao Tong University, Shanghai, 200240 (China)

2010-04-15

A mathematical model of a free piston linear engine is established. The motion characteristics as well as the natural frequency map of the free piston are established. Then, its motion characteristics are successfully explained from the oscillation point. The full simulation model is built up in Matlab/Simulink for a better understanding of its motion features. The results show that the free piston system is a forced vibration system with variable damping coefficient and stiffness. Its steady-state response of periodical excitation is convergent which means that the system is stable under the periodical combustion. Furthermore, it has some unique features which are different from those of traditional Internal Combustion (IC) engines. (author)

Numerical simulation of two-piston light gas gun for pellet injection in tokamaks

International Nuclear Information System (INIS)

Shi Yumei; He Yaling; Chen Zhongqi; Wu Peiyi

1995-01-01

Analysing the shortcoming of the single-piston light gas gun, the author uses the method of characteristics to estimate the performance of the two-piston light gas gun, and compare it with the single-piston gun, the result shows that two-piston gun has advantage on the aspect of the pressure pulse that promotes the pellet. The effects of some important parameters are also discussed. This work provides the theoretical basis for the design and optimization of two-piston light gas gun

Modeling, simulation, and identification of the servo pumps

Energy Technology Data Exchange (ETDEWEB)

Negoita, C G; Vasiliu, D; Vasiliu, Ne; Calinoiu, C, E-mail: claudia.negoita@gmail.co [Faculty of Power Engineering, University POLITEHNICA of Bucharest 313, Splaiul Independentei, Bucharest, 060042 (Romania)

2010-08-15

This paper contains the results of a systematic research on the steady-state behavior, and the transients occurring in a basic hydrostatic system containing a servo pump. The optimum structure of such a device working in given condition is found step by step, the synthesis stages are alternating with the analysis ones, in order to establish some general synthesis criteria, as well as for creating some images of the design parameters influence on the real system dynamic behavior. The dynamic computation of the servo pumps is based on the experimental researches carried out by the authors on the control force of the variable displacement axial piston pumps. The analysis takes into account the pressure feedback, the rigid or spring mechanical feedback or the electrical position feedback. The theoretical models are developed by AMESim (Advanced Modeling and Simulation Environment for Systems Engineering). The experimental tests were performed by the aid of LabVIEW software from National Instruments Corporation in the frame of a national certified laboratory set up by the aid of Parker Hannifin Corporation.

Mathematical modeling of reciprocating pump

International Nuclear Information System (INIS)

Lee, Jong Kyeom; Jung, Jun Ki; Chai, Jang Bom; Lee, Jin Woo

2015-01-01

A new mathematical model is presented for the analysis and diagnosis of a high-pressure reciprocating pump system with three cylinders. The kinematic and hydrodynamic behaviors of the pump system are represented by the piston displacements, volume flow rates and pressures in its components, which are expressed as functions of the crankshaft angle. The flow interaction among the three cylinders, which was overlooked in the previous models, is considered in this model and its effect on the cylinder pressure profiles is investigated. The tuning parameters in the mathematical model are selected, and their values are adjusted to match the simulated and measured cylinder pressure profiles in each cylinder in a normal state. The damage parameter is selected in an abnormal state, and its value is adjusted to match the simulated and ensured pressure profiles under the condition of leakage in a valve. The value of the damage parameter over 300 cycles is calculated, and its probability density function is obtained for diagnosis and prognosis on the basis of the probabilistic feature of valve leakage.

The highlighting of an internal combustion engine piston ring radial oscillations

Directory of Open Access Journals (Sweden)

Djallel ZEBBAR

2016-06-01

Full Text Available This paper deals with the definition of the lube-oil film thickness in the piston ring cylinder liner junction of an internal combustion engine. At first, a mathematical model for the estimation of the film thickness is established. It is used to point out the oscillating motion of the piston ring normal to the cylinder wall. For the first time, has been highlighted and analytically evaluated the oscillating behavior of the piston ring in its housing in the radial direction. Furthermore, it is demonstrated that the radial oscillations frequency is a function of piston ring stiffness, material and geometry.

Multiple Cylinder Free-Piston Stirling Machinery

Science.gov (United States)

Berchowitz, David M.; Kwon, Yong-Rak

In order to improve the specific power of piston-cylinder type machinery, there is a point in capacity or power where an advantage accrues with increasing number of piston-cylinder assemblies. In the case of Stirling machinery where primary energy is transferred across the casing wall of the machine, this consideration is even more important. This is due primarily to the difference in scaling of basic power and the required heat transfer. Heat transfer is found to be progressively limited as the size of the machine increases. Multiple cylinder machines tend to preserve the surface area to volume ratio at more favorable levels. In addition, the spring effect of the working gas in the so-called alpha configuration is often sufficient to provide a high frequency resonance point that improves the specific power. There are a number of possible multiple cylinder configurations. The simplest is an opposed pair of piston-displacer machines (beta configuration). A three-cylinder machine requires stepped pistons to obtain proper volume phase relationships. Four to six cylinder configurations are also possible. A small demonstrator inline four cylinder alpha machine has been built to demonstrate both cooling operation and power generation. Data from this machine verifies theoretical expectations and is used to extrapolate the performance of future machines. Vibration levels are discussed and it is argued that some multiple cylinder machines have no linear component to the casing vibration but may have a nutating couple. Example applications are discussed ranging from general purpose coolers, computer cooling, exhaust heat power extraction and some high power engines.

Selection of parameters for mud pumps used for HDD Systems

Directory of Open Access Journals (Sweden)

Jan Ziaja

2006-10-01

Full Text Available Design solutions of rigs used for HDD are presented in the paper. HDD devices are classified on the basis of presented criteria, and then a division of rigs was proposed. The principles of determining technological parameters of piston mud pumps for HDD are presented. The principles of determining volume flow rate for an arbitrary rheological model of drilling mud are discussed. The dependences enabling a calculation of resistance of drilling fluid flow in a circulation system are also presented.

Repetitive 1 Hz fast-heating fusion driver HAMA pumped by diode pumped solid state laser

International Nuclear Information System (INIS)

Mori, Yoshitaka; Sekine, Takashi; Komeda, Osamu

2014-01-01

We describe a repetitive fast-heating fusion driver called HAMA pumped by Diode Pumped Solid State Laser (DPSSL) to realize the counter irradiation of sequential implosion and heating laser beams. HAMA was designed to activate DPSSL for inertial confinement fusion (ICF) research and to realize a unified ICF machine for power plants. The details of a four-beam alignment scheme and the results of the counter irradiation of stainless plates are shown. (author)

Piston-rotaxanes as molecular shock absorbers.

Science.gov (United States)

Sevick, E M; Williams, D R M

2010-04-20

We describe the thermomechanical response of a new molecular system that behaves as a shock absorber. The system consists of a rodlike rotaxane connected to a piston and tethered to a surface. The response of this system is dominated by the translational entropy of the rotaxane rings and can be calculated exactly. The force laws are contrasted with those for a rigid rod and a polymer. In some cases, the rotaxanes undergo a sudden transition to a tilted state when compressed. These piston-rotaxanes provide a potential motif for the design of a new class of materials with a novel thermomechanical response.

Energy efficient piston configuration for effective air motion – A CFD study

International Nuclear Information System (INIS)

Gnana Sagaya Raj, Antony Raj; Mallikarjuna, Jawali Maharudrappa; Ganesan, Venkitachalam

2013-01-01

Highlights: ► All piston crown show similar flow pattern for experimental and simulated studies. ► Piston position plays a predominant role in the air pattern inside the cylinder. ► The flat bowl piston shows higher TKE compared to all other piston crown shape. ► The turbulence intensity and length scale are higher for flat bowl piston. ► The quantitative error between the CFD and PIV analysis is about 5%. -- Abstract: Air motion inside the cylinder is very important from the point of view of energy efficiency. In this direction, piston configuration plays a very crucial role. This study is concerned with the CFD analysis of in-cylinder air motion coupled with the comparison of predicted results with the experimental results available in the literature. Four configurations viz., flat, inclined, centre bowl and inclined offset bowl pistons have been studied. For numerical analysis STAR-CD CFD software has been used. Experimental results available in the literature for comparison are obtained by PIV measurements. From this study, it is concluded that a centre bowl on flat piston is found to be the best from the point of view of tumble ratio, turbulent kinetic energy, turbulent intensity and turbulent length scale which play very important role in imparting proper air motion, there by increasing the energy efficiency of the engine.

Optimised intake stroke analysis for flat and dome head pistons ...

African Journals Online (AJOL)

Optimised intake stroke analysis for flat and dome head pistons. ... in understanding the performance characteristics optioned between flat head and dome head pistons in engine design. ... EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT

Advantages and disadvantages of composite pistons for small power combustion engines

Directory of Open Access Journals (Sweden)

Andrzej POSMYK

2007-01-01

Full Text Available The results of technological and metallographic investigations of small dimensions, low power combustion engines piston has been presented. Semi-finished pistons has been produced by gravitations casting of composite material with EN-AC-47000 alloy matrix +15% Al2O3P and EN-AW-6061 alloy matrix +22% Al2O3P. Some small casting defects have been detected during the cutting process of piston made of composite material with EN-AC-47000 alloy matrix +15% Al2O3P. These defects were sources of micro perforations. In the piston made of EN-AW-6061 alloy matrix has been any defects detected.

Single-piston alternative to Stirling engines

International Nuclear Information System (INIS)

Glushenkov, Maxim; Sprenkeler, Martin; Kronberg, Alexander; Kirillov, Valeriy

2012-01-01

Highlights: ► Thermodynamic analysis of an unconventional heat engine. ► The engine has a number of advantages compared to state-of-the-art Stirling engines. ► The engine can to be fuelled with “difficult” fuels and used for micro-CHP systems. ► The energy conversion efficiency can be as high as 40–50%. ► A prototype of the engine was demonstrated. -- Abstract: Thermodynamic analysis of an unconventional heat engine was performed. The engine studied has a number of advantages compared to state-of-the-art Stirling engines. The main advantage of the engine proposed is its simplicity. A power piston is integral with a displacer and a heat regenerator. It allows solving the problem of the high-temperature sealing of the piston and the displacer typical of all types of Stirling engines. In addition the design proposed provides ideal use of the displacer volume eliminating heat losses from outside gas circuit. Both strokes of the piston are working ones in contrary to any other types of piston engines. The engine can be considered as maintenance-free as it has no piston rings or any other rubbing components requiring lubrication. The only seal is contactless and wear free. It is located in the cold part of the cylinder. As a result the leakage rate in operation can be one-two orders of magnitude as small as that in Stirling engines. Balancing of the engine is much easy compared to Stirling engines with two reciprocating masses because of the only moving part inside the engine cylinder. The engine suits ideally to be fuelled with “difficult” fuels such as bio oil and can be used as a prime mover for micro-CHP systems. The thermodynamic model developed incorporates non-ideal features of the cycle, such as specific regenerator efficiency, dead volumes and other geometrical parameters of the engine. The model shows that the energy efficiency is highly sensitive to regenerator performance. For realistic geometric and operating parameters and the

A computational study of free-piston diesel engine combustion

Energy Technology Data Exchange (ETDEWEB)

Mikalsen, R.; Roskilly, A.P. [Sir Joseph Swan Institute for Energy Research, Newcastle University, Devonshire Building, Newcastle upon Tyne, NE1 7RU (United Kingdom)

2009-07-15

This paper investigates the in-cylinder gas motion, combustion process and nitrogen oxide formation in a free-piston diesel engine and compares the results to those of a conventional engine, using a computational fluid dynamics engine model. Enhanced radial gas flow (squish and reverse squish) around top dead centre is found for the free-piston engine compared to a conventional engine, however it is found that this has only minor influence on the combustion process. A higher heat release rate from the pre-mixed combustion phase due to an increased ignition delay was found, along with potential reductions in nitrogen oxides emissions formation for the free-piston engine. (author)

Experimental Investigation of Piston Rings for Internal Combustion Engines

DEFF Research Database (Denmark)

Klit, Peder; Vølund, Anders

2008-01-01

absorbed in the bearing. Since the frictional forces are small compared to the rest of the acting forces the rig is designed such that the piston is fixed while the cylinder liner moves. This approach makes it simple to measure the parameters mentioned above by putting the instrumentation in the piston...

Pumped two-phase heat transfer loop

Science.gov (United States)

Edelstein, Fred

1988-01-01

A pumped loop two-phase heat transfer system, operating at a nearly constant temperature throughout, includes several independently operating grooved capillary heat exchanger plates supplied with working fluid through independent flow modulation valves connected to a liquid supply line, a vapor line for collecting vapor from the heat exchangers, a condenser between the vapor and the liquid lines, and a fluid circulating pump between the condenser and the heat exchangers.

Nuclear piston engine and pulsed gaseous core reactor power systems

International Nuclear Information System (INIS)

Dugan, E.T.

1976-01-01

The investigated nuclear piston engines consist of a pulsed, gaseous core reactor enclosed by a moderating-reflecting cylinder and piston assembly and operate on a thermodynamic cycle similar to the internal combustion engine. The primary working fluid is a mixture of uranium hexafluoride, UF 6 , and helium, He, gases. Highly enriched UF 6 gas is the reactor fuel. The helium is added to enhance the thermodynamic and heat transfer characteristics of the primary working fluid and also to provide a neutron flux flattening effect in the cylindrical core. Two and four-stroke engines have been studied in which a neutron source is the counterpart of the sparkplug in the internal combustion engine. The piston motions which have been investigated include pure simple harmonic, simple harmonic with dwell periods, and simple harmonic in combination with non-simple harmonic motion. The results of the conducted investigations indicate good performance potential for the nuclear piston engine with overall efficiencies of as high as 50 percent for nuclear piston engine power generating units of from 10 to 50 Mw(e) capacity. Larger plants can be conceptually designed by increasing the number of pistons, with the mechanical complexity and physical size as the probable limiting factors. The primary uses for such power systems would be for small mobile and fixed ground-based power generation (especially for peaking units for electrical utilities) and also for nautical propulsion and ship power

Structural design of Stirling engine with free pistons

Science.gov (United States)

Matusov, Jozef; Gavlas, Stanislav; Malcho, Milan

2014-08-01

Stirling engine is a device that converts thermal energy to mechanical work, which is mostly used to drive a generator of electricity. Advantage of Stirling engine is that it works with closed-cycle, where working medium is regularly cooled and heated, which acts on the working piston. This engine can be made in three modifications - alpha, beta, gamma. This paper discusses the design of the gamma Stirling engine with free pistons.

TRIBOLOGICAL PERFORMANCE OF PISTON RING IN MARINE DIESEL ENGINE

DEFF Research Database (Denmark)

Imran, Tajammal; Klit, Peder; Felter, Christian

From a tribology point of view, it is the two dead centers that are the main area of interest for experimental study of piston rings in large marine diesel engines. Therefore, in this work the performance of piston rings is studied to mark the importance of the two dead centers. A test rig based...

Vacuum pumping by the halo plasma

International Nuclear Information System (INIS)

Barr, W.L.

1985-01-01

An estimate is made of the effective vacuum pumping speed of the halo plasma in a tandem mirror fusion reactor, and it is shown that, if the electron temperature and line density are great enough, the halo can be a very good vacuum pump. One can probably obtain the required density by recycling the ions at the halo dumps. An array of small venting ports in the dump plates allows local variation of the recycle fraction and local removal of the gas at a conveniently high pressure. This vented-port concept could introduce more flexibility in the design of pumped limiters for tokamaks

Acoustic emission testing of piston check valves

International Nuclear Information System (INIS)

Stewart, D.L.

1994-01-01

Based on test experience at Comanche Peak Unit 1, an acoustic emission data evaluation matrix for piston check valves has been developed. The degradations represented in this matrix were selected based on Edwards piston check valve failure data reported in the Nuclear Plant Reliability Data System. Evidence to support this matrix was collected from site test data on a variety of valve types. Although still under refinement, the matrix provides three major attributes for closure verification, which have proven useful in developing test procedures for inservice testing and preventing unnecessary disassembly

Hearing results using the SMart piston prosthesis.

Science.gov (United States)

Fayad, Jose N; Semaan, Maroun T; Meier, Josh C; House, John W

2009-12-01

SMart, a newly introduced piston prosthesis for stapedotomy, is a nitinol-based, heat-activated, self-crimping prosthesis. We review our hearing results and postoperative complications using this self-crimped piston prosthesis and compare them with those obtained using stainless steel or platinum piston prostheses. Audiometric results using the SMart piston are identical to those obtained using a conventional piston prosthesis. Retrospective chart review. Private neurotologic tertiary referral center. The 416 ears reviewed included 306 with a SMart prosthesis and 110 conventional prostheses. 61% were women. Mean follow-up time was 5.6 (standard deviation [SD], 6.3 mo) and 6.9 months (SD, 7.0 mo) for the 2 groups, respectively. Stapedotomy using the SMart or a conventional (non-SMart) prosthesis. Audiometric hearing results, including pure-tone average (PTA) and air-bone gap (ABG), and prevalence of postoperative complications. Mean postoperative PTA was 32.6 (SD, 16.8) dB for the SMart group and 29.4 (SD, 13.5) dB for the non-SMart group, with ABGs of 7.6 (SD, 8.9) and 6.0 (SD, 5.2) dB, respectively. Mean change (decrease) in ABG was 18.7 (SD, 13.1) dB for the SMart group and 19.9 (SD, 10.3) dB for the non-SMart group. High-frequency bone PTAs showed overclosure of 2.0 (SD, 7.9) dB for the SMart group and 3.6 (SD, 8.6) dB for the non-SMart group. Postoperative vertigo and tinnitus were infrequent. No significant differences in these audiometric outcomes or complication rates were noted between groups. There was no significant difference in rate of gap closure to within 10 dB (78.3 versus 84.2%, SMart and non-SMart, respectively) or 20 dB (94.2 and 98.0%). Compared with conventional stapes prostheses, the nitinol-based SMart is a safe and reliable stapes prosthesis that eliminates manual crimping without significantly altering the audiometric outcome. Complications are rare, but longer follow-up is needed before establishing long-term stability.

Symmetry of the Adiabatic Condition in the Piston Problem

Science.gov (United States)

Anacleto, Joaquim; Ferreira, J. M.

2011-01-01

This study addresses a controversial issue in the adiabatic piston problem, namely that of the piston being adiabatic when it is fixed but no longer so when it can move freely. It is shown that this apparent contradiction arises from the usual definition of adiabatic condition. The issue is addressed here by requiring the adiabatic condition to be…

Self-pumping inpurity control systems for INTOR

International Nuclear Information System (INIS)

Brooks, J.N.; Mattas, R.F.; Smith, D.L.; Hassanein, A.M.

1987-01-01

Two self-pumping systems have been examined for use as the INTOR impurity control system. The systems work by trapping helium in freshly deposited metal surface layers on or near the divertor plate. A slot divertor concept using vanadium or other trapping material appears to be both feasible and mechanically simple, and offers significant advantages in cost, reduced complexity, and helium pumping efficiency for the INTOR design

Development of cryogenic free-piston reciprocating expander utilizing phase controller

Energy Technology Data Exchange (ETDEWEB)

Cha, Jeong Min; Park, Ji Ho; Kim, Kyung Joong; Jeong, Sang Kwon [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

2016-06-15

A free-piston reciprocating expander is a device which operates without any mechanical linkage to a stationary part. Since the motion of the floating piston is only controlled by the pressure difference at two ends of the piston, this kind of expander may indispensably require a sophisticated active control system equipped with multiple valves and reservoirs. In this paper, we have suggested a novel design that can further reduce complexity of the previously developed cryogenic free-piston expander configuration. It is a simple replacement of both multiple valves and reservoirs by a combination of an orifice valve and a reservoir. The functional characteristic of the integrated orifice-reservoir configuration is similar to that of a phase controller applied in a pulse tube refrigerator so that we designate the one as a phase controller. Depending on the orifice valve size in the phase controller, the different PV work which affects the expander performance is generated. The numerical model of this unique free-piston reciprocating expander utilizing a phase controller is established to understand and analyze quantitatively the performance variation of the expander under different valve timing and orifice valve size. The room temperature experiments are carried out to examine the performance of this newly developed cryogenic expander.

Development of cryogenic free-piston reciprocating expander utilizing phase controller

International Nuclear Information System (INIS)

Cha, Jeong Min; Park, Ji Ho; Kim, Kyung Joong; Jeong, Sang Kwon

2016-01-01

A free-piston reciprocating expander is a device which operates without any mechanical linkage to a stationary part. Since the motion of the floating piston is only controlled by the pressure difference at two ends of the piston, this kind of expander may indispensably require a sophisticated active control system equipped with multiple valves and reservoirs. In this paper, we have suggested a novel design that can further reduce complexity of the previously developed cryogenic free-piston expander configuration. It is a simple replacement of both multiple valves and reservoirs by a combination of an orifice valve and a reservoir. The functional characteristic of the integrated orifice-reservoir configuration is similar to that of a phase controller applied in a pulse tube refrigerator so that we designate the one as a phase controller. Depending on the orifice valve size in the phase controller, the different PV work which affects the expander performance is generated. The numerical model of this unique free-piston reciprocating expander utilizing a phase controller is established to understand and analyze quantitatively the performance variation of the expander under different valve timing and orifice valve size. The room temperature experiments are carried out to examine the performance of this newly developed cryogenic expander

Radial holding device of the tube bundle casing and of the tube support plates by elastic stops

International Nuclear Information System (INIS)

Comic, G.

1995-01-01

Each stop comprises a first piece fixed on the tube bundle casing and contacting the inner face of the pressure casing by the intermediary of screws. A second piece abutting the tube support plate and constraining it is housed to form a piston in a cavity of the first piece. 5 figs

Dry piston coal feeder

Science.gov (United States)

Hathaway, Thomas J.; Bell, Jr., Harold S.

1979-01-01

This invention provides a solids feeder for feeding dry coal to a pressurized gasifier at elevated temperatures substantially without losing gas from the gasifier by providing a lock having a double-acting piston that feeds the coals into the gasifier, traps the gas from escaping, and expels the trapped gas back into the gasifier.

Experimental Evaluation of the Free Piston Engine - Linear Alternator (FPLA)

Energy Technology Data Exchange (ETDEWEB)

Leick, Michael T. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Moses, Ronald W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-03-01

This report describes the experimental evaluation of a prototype free piston engine - linear alternator (FPLA) system developed at Sandia National Laboratories. The opposed piston design wa developed to investigate its potential for use in hybrid electric vehicles (HEVs). The system is mechanically simple with two - stroke uniflow scavenging for gas exchange and timed port fuel injection for fuel delivery, i.e. no complex valving. Electrical power is extracted from piston motion through linear alternators wh ich also provide a means for passive piston synchronization through electromagnetic coupling. In an HEV application, this electrical power would be used to charge the batteries. The engine - alternator system was designed, assembled and operated over a 2 - year period at Sandia National Laboratories in Livermore, CA. This report primarily contains a description of the as - built system, modifications to the system to enable better performance, and experimental results from start - up, motoring, and hydrogen combus tion tests.

Durability, Performance, and Emission of Diesel Engines Using Carbon Fiber Piston and Liner

Science.gov (United States)

Afify, E. M.; Roberts, W. L.

1999-01-01

This report summarizes the research conducted by NC State University in investigating the durability, performance and emission of a carbon fiber piston and liner in our single cylinder research Diesel engine. Both the piston and liner were supplied to NC State University by NASA LaRC and manufactured by C-CAT under a separate contract to NASA LaRC. The carbon-carbon material used to manufacture the piston and liner has significantly lower thermal conductivity, coefficient of thermal expansion, and superior strength characteristics at elevated temperatures when compared to conventional piston materials such as aluminum. The results of the carbon-carbon fiber piston testing were compared to a baseline configuration, which used a conventional aluminum piston in a steel liner. The parameters measured were the brake specific fuel consumption, ignition delay, frictional horsepower, volumetric efficiency, and durability characteristics of the two pistons. Testing was performed using a naturally aspirated Labeco Direct Injection single cylinder diesel engine. Two test cases were performed over a range of loads and speeds. The fixed test condition between the aluminum and carbon-carbon piston configurations was the brake mean effective pressure. The measured data was the fuel consumption rate, volumetric efficiency, load, speed, cylinder pressure, needle lift, and exhaust gas temperature. The cylinder pressure, and fuel consumption, exhaust gas temperature, and needle lift were recorded using a National Instruments DAQ board and a PC. All test cases used Diesel no. 2 for fuel.

Limiting density ratios in piston-driven compressions

International Nuclear Information System (INIS)

Lee, S.

1985-07-01

By using global energy and pressure balance applied to a shock model it is shown that for a piston-driven fast compression, the maximum compression ratio is not dependent on the absolute magnitude of the piston power, but rather on the power pulse shape. Specific cases are considered and a maximum density compression ratio of 27 is obtained for a square-pulse power compressing a spherical pellet with specific heat ratio of 5/3. Double pulsing enhances the density compression ratio to 1750 in the case of linearly rising compression pulses. Using this method further enhancement by multiple pulsing becomes obvious. (author)

The effect of surface roughness on the performances of liner-piston ...

African Journals Online (AJOL)

The effect of surface roughness on the performances of liner-piston ring contact in internal combustion engine. ... The surface roughness between the liner and the piston rings, plays an ... EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT

Vibration isolation in a free-piston driven expansion tube facility

Science.gov (United States)

Gildfind, D. E.; Jacobs, P. A.; Morgan, R. G.

2013-09-01

The stress waves produced by rapid piston deceleration are a fundamental feature of free-piston driven expansion tubes, and wave propagation has to be considered in the design process. For lower enthalpy test conditions, these waves can traverse the tube ahead of critical flow processes, severely interfering with static pressure measurements of the passing flow. This paper details a new device which decouples the driven tube from the free-piston driver, and thus prevents transmission of stress waves. Following successful incorporation of the concept in the smaller X2 facility, it has now been applied to the larger X3 facility, and results for both facilities are presented.

Particle shedding from peristaltic pump tubing in biopharmaceutical drug product manufacturing.

Science.gov (United States)

Saller, Verena; Matilainen, Julia; Grauschopf, Ulla; Bechtold-Peters, Karoline; Mahler, Hanns-Christian; Friess, Wolfgang

2015-04-01

In a typical manufacturing setup for biopharmaceutical drug products, the fill and dosing pump is placed after the final sterile filtration unit in order to ensure adequate dispensing accuracy and avoid backpressure peaks. Given the sensitivity of protein molecules, peristaltic pumps are often preferred over piston pumps. However, particles may be shed from the silicone tubing employed. In this study, particle shedding and a potential turbidity increase during peristaltic pumping of water and buffer were investigated using three types of commercially available silicone tubing. In the recirculates, mainly particles of around 200 nm next to a very small fraction of particles in the lower micrometer range were found. Using 3D laser scanning microscopy, surface roughness of the inner tubing surface was found to be a determining factor for particle shedding from silicone tubing. As the propensity toward particle shedding varied between tubing types and also cannot be concluded from manufacturer's specifications, individual testing with the presented methods is recommended during tubing qualification. Choosing low abrasive tubing can help to further minimize the very low particle counts to be expected in pharmaceutical drug products. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

Casimir pistons with general boundary conditions

Directory of Open Access Journals (Sweden)

Guglielmo Fucci

2015-02-01

Full Text Available In this work we analyze the Casimir energy and force for a scalar field endowed with general self-adjoint boundary conditions propagating in a higher dimensional piston configuration. The piston is constructed as a direct product I×N, with I=[0,L]⊂R and N a smooth, compact Riemannian manifold with or without boundary. The study of the Casimir energy and force for this configuration is performed by employing the spectral zeta function regularization technique. The obtained analytic results depend explicitly on the spectral zeta function associated with the manifold N and the parameters describing the general boundary conditions imposed. These results are then specialized to the case in which the manifold N is a d-dimensional sphere.

Computer Aided Design of Kaplan Turbine Piston with SolidWorks

OpenAIRE

Camelia Jianu

2010-01-01

The paper presents the steps for 3D computer aided design (CAD) of Kaplan turbine piston made in SolidWorks.The present paper is a tutorial for a Kaplan turbine piston 3D geometry, which is dedicaded to the Parts Sketch and Parts Features design and Drawing Geometry and Drawing Annotation.

Experimental investigation of the unsteady two-phase flow through perforated plates

International Nuclear Information System (INIS)

Tartaglia, G.P.

1985-07-01

The coolant flow across the perforated dip-plate during a hypothetical core disruptive accident (HCDA) in a liquid metal fast breeder reactor was simulated in a one-dimensional model. Experiments with a water-air mixture as fluid were run by varying the following parameters: geometry of the dip-plate (perforation ratio, number of the holes), height of the fluid head over the dip-plate, air volumetric fraction, size of the air bubbles, acceleration of the fluid. The pressure drop across the dip-plate, the forces acting on the dip-plate and on the upper plate, acceleration and displacement of the piston, the air volumetric fraction and the size of the air bubbles were measured in a wide range of Strouhal and acceleration numbers. The flow pattern downstream the dip-plate was filmed with a high-speed camera. The following correlations were investigated: resistance coefficients as a function of the acceleration and Strouhal number, time delay of the force on the upper plate as a function of the cavitation number, and forces and impulses acting on the upper plate compared with those acting on the dip-plate. Finally, using high-speed film pictures, the formation of fluid jets downstream the dip-plate was investigated. The following relations were obtained: displacement of the mixture surface and of the jets as a function of the perforation ratio and of the air volumetric fraction, and cavitation volume as a function of the cavitation number. (orig.) [de

Performance analysis of a miniature free piston expander for waste heat energy harvesting

International Nuclear Information System (INIS)

Champagne, C.; Weiss, L.

2013-01-01

Highlights: • A novel free piston expander is experimentally analyzed for waste heat retrieval. • A variety of variables are analyzed using three separate experiments. • Lubrication of device is optimized with lower viscosity lubricants. • Circular cross sectional pistons show increased repeatability and sealing. - Abstract: Initial experimental analysis of a small-scale Free Piston Expander (FPE) is presented. In final form, the FPE will be a MEMS-based device capable of operation from low temperature waste heat sources. Currently, a millimeter scale device is constructed and tested to yield insight into critical operational parameters for use in later design and testing. Operating conditions are examined to increase operational performance. Piston stroke length and repeatability are considered. Optimized variables include piston length and mass, FPE shape and size, input pressure, and lubrication. Construction of this testbed device is via concentric copper tubing, allowing an effective baseline study of these determining parameters. Results show that, while thick lubricants seal well in static configurations, piston motion is decreased in dynamic testing, indicating leakage. By contrast, reduced viscosity lubricants prove ineffective as sealing agents during static conditions, however, yield increased piston motion in dynamic testing with little leakage around critical piston sealing surfaces. The trends established by the study of varying viscosity lubricants hold true for pistons of increasing mass and length as well. A mixture of isopropanol and water performed well in these tests, and represented a low viscosity sealing fluid, which was used in later repeatability tests. Repeatability tests were performed in a closed dynamic environment on FPE designs with multiple cross sectional shapes and areas. Results from these tests show that circular FPE’s are more precise than square FPE’s. The final closed system tests yield a pressure–volume curve

On the Potential of Hydrogen-Powered Hydraulic Pumps for Soft Robotics.

Science.gov (United States)

Desbiens, Alexandre B; Bigué, Jean-Philippe Lucking; Véronneau, Catherine; Masson, Patrice; Iagnemma, Karl; Plante, Jean-Sébastien

2017-12-01

To perform untethered operations, soft robots require mesoscale power units (10-1000 W) with high energy densities. In this perspective, air-breathing combustion offers an interesting alternative to battery-powered systems, provided sufficient overall energy conversion efficiency can be reached. Implementing efficient air-breathing combustion in mesoscale soft robots is notoriously difficult, however, as it requires optimization of very small combustion actuators and simultaneous minimization of fluidic (e.g., hydraulic) losses, which are both inversely impacted by actuations speeds. To overcome such challenges, this article proposes and evaluates the potential of hydrogen-powered, hydraulic free-piston pump architecture. Experimental data, taken from two combustion-driven prototypes, reveal (1) the fundamental role of using hydrogen as the source of fuel to reduce heat losses, (2) the significant impact of compression ratio, equivalence ratio, and surface-to-volume ratio on energy conversion efficiency, and (3) the importance of load matching between combustion and fluidic transmission. In this work, a small-bore combustion actuator demonstrated a 20% efficiency and a net mean output power of 26 W, while a big-bore combustion actuator reached a substantially higher efficiency of 35% and a net mean output power of 197 W. Using the small-bore combustion actuator, the hydrogen-powered, hydraulic free-piston pump provided a 4.6% overall efficiency for a 2.34 W net mean output power, thus underlying the potential of the approach for mesoscale soft robotic applications.

An electrochemical pumping system for on-chip gradient generation.

Science.gov (United States)

Xie, Jun; Miao, Yunan; Shih, Jason; He, Qing; Liu, Jun; Tai, Yu-Chong; Lee, Terry D

2004-07-01

Within the context of microfluidic systems, it has been difficult to devise pumping systems that can deliver adequate flow rates at high pressure for applications such as HPLC. An on-chip electrochemical pumping system based on electrolysis that offers certain advantages over designs that utilize electroosmotic driven flow has been fabricated and tested. The pump was fabricated on both silicon and glass substrates using photolithography. The electrolysis electrodes were formed from either platinum or gold, and SU8, an epoxy-based photoresist, was used to form the pump chambers. A glass cover plate and a poly(dimethylsiloxane) (PDMS) gasket were used to seal the chambers. Filling of the chambers was accomplished by using a syringe to inject liquid via filling ports, which were later sealed using a glass cover plate. The current supplied to the electrodes controlled the rate of gas formation and, thus, the resulting fluid flow rate. At low backpressures, flow rates >1 microL/min have been demonstrated using polymer electrospray nozzle, we have confirmed the successful generation of a solvent gradient via a mass spectrometer.

Energy storage by compressed air. [using windpowered pumps

Science.gov (United States)

Szego, G. C.

1973-01-01

The feasibility of windpower energy storage by compressed air is considered. The system is comprised of a compressor, a motor, and a pump turbine to store air in caverns or aquifiers. It is proposed that storage of several days worth of compressed air up to 650 pounds per square inch can be used to push the aquifier up closer to the container dome and thus initiate piston action by simply compressing air more and more. More energy can be put into it by pressure increase or pushing back the water in the aquifier. This storage system concept has reheat flexibility and lowest cost effectiveness.

Heat flows in piston compressors

NARCIS (Netherlands)

Lekic, U.; Kok, J.B.W.; van der Meer, T.H.; van Steenhoven, A.A.; Stoffels, G.G.M.

2008-01-01

Piston compressors are widely used in today's engineering applications. Among the most important applications is however the compression of thermal carrier gas in Rankine and Stirling refrigeration cycles. Fluids used in these cycles are commonly Ammonia and Helium. In order to improve the design

Neutral pumping rates for a next step tokamak ignition device

International Nuclear Information System (INIS)

Galambos, J.D.; Peng, Y.K.M.; Heifetz, D.

1985-01-01

Neutral pumping rates are calculated for pump-limiter and divertor options of a next step tokamak ignition device using a method that accounts for the coupled effects of neutral transport and plasma transport. For both pump limiters and divertors the plasma flow into the channel surrounding the neutralizer plate is greatly reduced by the neutral recycling. The fraction of this flow that is pumped can be large (>50%) but in general is dependent on the particular geometry and plasma conditions. It is estimated that pumping speeds greater than or approximately 10 5 L/s are adequate for the exhaust requirements in the pump-limiter and the divertor cases

Metastability-exchange optical pumping of 3He for neutron polarizers

International Nuclear Information System (INIS)

Gentile, T.R.; Thompson, A.K.; Snow, W.M.

1995-01-01

Research is underway at NIST and IU to develop neutron polarizers that are based on polarized 3 He. Such polarizers rely on the strong spin dependence of the cross section for neutron capture by polarized 3 He. Two methods can produce the high density of polarized 3 He gas (10 19 -10 20 cm -3 ) required for an effective neutron polarizer: spin-exchange optical pumping, which is performed directly at high pressure (1-10 bar), and metastability-exchange optical pumping, in which the gas is polarized at low pressure (1 mbar) and then compressed. While we are pursuing both methods, progress in the metastable method will be discussed. The features of the metastable method are the high rate at which the gas can be polarized and the inherent separation of the optical pumping and target cells. In a landmark achievement, researchers at the Univ. of Mainz have developed a piston compressor that can fill a 130 cm 3 cell to a pressure of 7 bar of 45% polarized 3 He gas in 2 hours. We plan to develop a compressor and test it at the NIST Cold Neutron Research Facility. We have constructed a metastable-pumping apparatus at NIST and have obtained 76% polarization with a pumping rate of 1.2 x 10 18 atoms/sec in a 0.4 mbar, 270 cm 3 cell

Valving for controlling a fluid-driven reciprocating apparatus

Science.gov (United States)

Whitehead, John C.

1995-01-01

A pair of control valve assemblies for alternately actuating a pair of fluid-driven free-piston devices by using fluid pressure communication therebetween. Each control valve assembly is switched by a pressure signal depending on the state of its counterpart's piston. The communication logic is arranged to provide overlap of the forward strokes of the pistons, so that at least one of the pair will always be pressurized. Thus, uninterrupted pumping of liquid is made possible from a pair of free-piston pumps. In addition, the speed and frequency of piston stroking is entirely dependent on the mechanical power load applied. In the case of a pair of pumps, this enables liquid delivery at a substantially constant pressure over the full range of flow rates, from zero to maximum flow. Each of the valve assemblies uses an intake-exhaust valve and a signal valve with the signal valve of one pump being connected to be pressure responsive to the piston of the opposite cylinder or pump.

Experimental and simulation study on the plate absorber for hybrid heat pump system

Energy Technology Data Exchange (ETDEWEB)

An, Seung Sun; Jung, Chung Woo; Kang, Yong Tae [Kyung Hee University, Yongin (Korea, Republic of); Kim, Min Sung; Park, Seong Ryong [KIER, Daejeon (Korea, Republic of); Kang, Chae Dong [Chonbuk National University, Jeonju (Korea, Republic of)

2013-12-15

This research conducts an experiment for a hybrid heat pump system, using ammonia-water as a working fluid, to obtain a hot water of about 80 .deg. C. The hybrid heat pump system is the combination of vapor compression cycle and absorption cycle to improve the performance of the heat pump system. The hybrid heat pump system uses a low temperature heat source of about 50 .deg. C from the industrial waste heat. The system consists of absorber, desorber, solution heat exchanger, oil heat exchanger, rectifier, compressor and a solution pump. Parametric analysis is carried out experimentally and numerically for the key parameters such as the capacity of the absorber, the internal pressure change. From the present experimental study, it is found that the maximum hot water temperature is obtained to be 79.33 .deg. C.

Balanced pressure gerotor fuel pump

Energy Technology Data Exchange (ETDEWEB)

Raney, Michael Raymond; Maier, Eugen

2004-08-03

A gerotor pump for pressurizing gasoline fuel is capable of developing pressures up to 2.0 MPa with good mechanical and volumetric efficiency and satisfying the durability requirements for an automotive fuel pump. The pump has been designed with optimized clearances and by including features that promote the formation of lubricating films of pressurized fuel. Features of the improved pump include the use of a shadow port in the side plate opposite the outlet port to promote balancing of high fuel pressures on the opposite sides of the rotors. Inner and outer rotors have predetermined side clearances with the clearances of the outer rotor being greater than those of the inner rotor in order to promote fuel pressure balance on the sides of the outer rotor. Support of the inner rotor and a drive shaft on a single bushing with bearing sleeves maintains concentricity. Additional features are disclosed.

Demonstration of a free piston Stirling engine driven linear alternator, phase I report

International Nuclear Information System (INIS)

Goldwater, B.; Piller, S.; Rauch, J.; Cella, A.

1977-01-01

The results of the work performed under Phase I of the free piston Stirling engine demonstrator program are described. The objective of the program is to develop a 2 kW free piston Stirling engine/linear alternator energy conversion system, for an isotopic heat source, with a greater than 30% overall efficiency. Phase I was a 15-month effort to demonstrate the feasibility of the system through analysis and experimental testing of the individual components. An introduction to Stirling engines and the details of the tasks completed are presented in five major sections: (1) introduction to Stirling engine; (2) preliminary design of an advanced free piston Stirling demonstrator engine; (3) design and test of a 1 kWE output linear alternator; (4) test of a model free piston Stirling engine; and (5) development of a free piston Stirling engine computer simulation code

Demonstration of a free piston Stirling engine driven linear alternator, phase I report

Energy Technology Data Exchange (ETDEWEB)

Goldwater, B.; Piller, S.; Rauch, J.; Cella, A.

1977-03-30

The results of the work performed under Phase I of the free piston Stirling engine demonstrator program are described. The objective of the program is to develop a 2 kW free piston Stirling engine/linear alternator energy conversion system, for an isotopic heat source, with a greater than 30% overall efficiency. Phase I was a 15-month effort to demonstrate the feasibility of the system through analysis and experimental testing of the individual components. An introduction to Stirling engines and the details of the tasks completed are presented in five major sections: (1) introduction to Stirling engine; (2) preliminary design of an advanced free piston Stirling demonstrator engine; (3) design and test of a 1 kWE output linear alternator; (4) test of a model free piston Stirling engine; and (5) development of a free piston Stirling engine computer simulation code.

Pump

International Nuclear Information System (INIS)

Mole, C.J.

1983-01-01

An electromagnetic pump for circulating liquid -metal coolant through a nuclear reactor wherein opposite walls of a pump duct serve as electrodes to transmit current radially through the liquid-metal in the ducts. A circumferential electric field is supplied to the liquid-metal by a toroidal electromagnet which has core sections interposed between the ducts. The windings of the electromagnet are composed of metal which is superconductive at low temperatures and the electromagnet is maintained at a temperature at which it is superconductive by liquid helium which is fed through the conductors which supply the excitation for the electromagnet. The walls of the ducts joining the electrodes include metal plates insulated from the electrodes backed up by insulators so that they are capable of withstanding the pressure of the liquid-metal. These composite wall structures may also be of thin metal strips of low electrical conductivity backed up by sturdy insulators. (author)

Wear testing and finite element analysis of nitrile rubber (NBR) hand pump seals

OpenAIRE

Alkadhimi, Fadel

2015-01-01

The use of Nitrile Butadiene Rubber NBR as seal in machines has increased in recent years. NBR is considered as the standard material for sealing and NBR owes its many applications to a range of special mechanical properties. However, the non-linear mechanical properties and incompressible behaviour of NBR make the analysis of NBR very difficult. The literature review highlighted the fact that the most common technical cause of hand pump failures was the wear of the piston seals. The contact ...

Assessment of 25 kW free-piston Stirling technology alternatives for solar applications

Science.gov (United States)

Erbeznik, Raymond M.; White, Maurice A.; Penswick, L. B.; Neely, Ronald E.; Ritter, Darren C.; Wallace, David A.

1992-01-01

The final design, construction, and testing of a 25-kW free-piston advanced Stirling conversion system (ASCS) are examined. The final design of the free-piston hydraulic ASCS consists of five subsystems: heat transport subsystem (solar receiver and pool boiler), free-piston hydraulic Stirling engine, hydraulic subsystem, cooling subsystem, and electrical and control subsystem. Advantages and disadvantages are identified for each technology alternative. Technology alternatives considered are gas bearings vs flexure bearings, stationary magnet linear alternator vs moving magnetic linear alternator, and seven different control options. Component designs are generated using available in-house procedures to meet the requirements of the free-piston Stirling convertor configurations.

Study of high-pressure cryogenic pumps with different methods of delivery control

International Nuclear Information System (INIS)

Braun, V.M.; Brailovskii, Y.L.; Pavlenko, Y.A.; Tsokalo, I.V.

1986-01-01

This paper describes new reciprocating pumps with smooth control of delivery in a running pump. Control is effected either by changing the length of the piston stroke or by changing the speed of the driving motor. The individual features of the two methods are described. In the first method (mechanical), delivery is controlled in the range 50 to 100%. A separate actuating mechanism is needed to connect the pump to an automatic control system. This method complicates the driving mechanism and increases the bulk and cost of production. In the second method of controlling the speed of the electric motor, an electric drive fitted with a frequency thyristor is used. AC induction motors series 4A working at current frequencies of 60 HZ are used. By this method, delivery control could be enhanced by 1.3 times. Comparative tests were made on pumps using the above methods of control. The tests demonstrated the possibilities of using the frequency thyristor converters. The complexity and high cost of EKT type drives is largely compensated by the convenience and simplicity of control in a wide range. The mechanical control is advantageous only in low-output units

3-D steady state thermomechanical analysis of a piston of a direct injection diesel engine

International Nuclear Information System (INIS)

Abid, M.; Bannikov, M.G.; Ali, H.

2005-01-01

Piston of internal combustion engine is subjected to the coupled action of the thermal and the mechanical loads. Piston distortion due to temperature nonuniformities has a significant impact on the piston component of the engine friction. In regions of high heat flux, thermal stresses can reach levels that would cause fatigue cracking. Any change of engine design and/or operating conditions resulting in an increased heat flux through the piston may cause engine performance deterioration and even engine failure. This work presents a three-dimensional finite element analysis of a piston of a high power direct injection diesel engine. The goal of such analysis was the prediction of the piston behavior in conditions of the increased brake mean effective pressure and engine speed. Thermal and mechanical loads required for analysis were obtained from the engine cycle simulation. Thermal boundary conditions were determined in the form of the cycle averaged temperature of combustion chamber content and cycle averaged spatially distributed heat transfer coefficients. Mechanical load was represented by the combined gas pressure and inertia forces. Using ANSYS software temperature and stress distributions within the piston body as well as piston deformation were obtained. Analysis was performed for separate as well as combined load. It was shown that contribution of mechanical load is insignificant and can be neglected. Main emphasis is given to scuffing and strength analysis of the piston. Results obtained at various thermal loads are discussed. (author)

Cooling device for leaking fluid from a centrifugal pump

International Nuclear Information System (INIS)

Raymond, J.R.; Thomson, C.I.

1978-01-01

The patented device consists of an integrated heat exchanger in a centrifugal primary cooling circuit pump whose purpose is to cool the coolant medium which leaks along the pump shaft so that the shaft seals are not damaged. The cooling water passes through spirally arranged banks of tubes round the shaft, with baffle plates to direct the leaking coolant. (JIW)

Thermoacoustic model of a modified free piston Stirling engine with a thermal buffer tube

International Nuclear Information System (INIS)

Yang, Qin; Luo, Ercang; Dai, Wei; Yu, Guoyao

2012-01-01

This article presents a modified free-piston Stirling heat engine configuration in which a thermal buffer tube is added to sandwich between the hot and cold heat exchangers. Such a modified configuration may lead to an easier fabrication and lighter weight of a free piston. To analyze the thermodynamic performance of the modified free piston Stirling heat engine, thermoacoustic theory is used. In the thermoacoustic modelling, the regenerator, the free piston, and the thermal buffer tube are given at first. Then, based on linear thermoacoustic network theory, the thermal and thermodynamic networks are presented to characterize acoustic pressure and volume flow rate distributions at different interfaces, and the global performance such as the power output, the heat input and the thermal efficiency. A free piston Stirling heat engine with several hundreds of watts mechanical power output is selected as an example. The typical operating and structure parameters are as follows: frequency around 50 Hz, mean pressure around 3.0 MPa, and a diameter of free piston around 50 mm. From the analysis, it was found that the modified free-piston Stirling heat engine has almost the same thermodynamic performance as the original design, which indicates that the modified configuration is worthy to develop in future because of its mechanical simplicity and reliability.

Adiabatic liquid piston compressed air energy storage

Energy Technology Data Exchange (ETDEWEB)

Petersen, Tage [Danish Technological Institute, Aarhus (Denmark); Elmegaard, B. [Technical Univ. of Denmark. DTU Mechanical Engineering, Kgs. Lyngby (Denmark); Schroeder Pedersen, A. [Technical Univ. of Denmark. DTU Energy Conversion, Risoe Campus, Roskilde (Denmark)

2013-01-15

This project investigates the potential of a Compressed Air Energy Storage system (CAES system). CAES systems are used to store mechanical energy in the form of compressed air. The systems use electricity to drive the compressor at times of low electricity demand with the purpose of converting the mechanical energy into electricity at times of high electricity demand. Two such systems are currently in operation; one in Germany (Huntorf) and one in the USA (Macintosh, Alabama). In both cases, an underground cavern is used as a pressure vessel for the storage of the compressed air. Both systems are in the range of 100 MW electrical power output with several hours of production stored as compressed air. In this range, enormous volumes are required, which make underground caverns the only economical way to design the pressure vessel. Both systems use axial turbine compressors to compress air when charging the system. The compression leads to a significant increase in temperature, and the heat generated is dumped into the ambient. This energy loss results in a low efficiency of the system, and when expanding the air, the expansion leads to a temperature drop reducing the mechanical output of the expansion turbines. To overcome this, fuel is burned to heat up the air prior to expansion. The fuel consumption causes a significant cost for the storage. Several suggestions have been made to store compression heat for later use during expansion and thereby avoid the use of fuel (so called Adiabatic CAES units), but no such units are in operation at present. The CAES system investigated in this project uses a different approach to avoid compression heat loss. The system uses a pre-compressed pressure vessel full of air. A liquid is pumped into the bottom of the vessel when charging and the same liquid is withdrawn through a turbine when discharging. In this case, the liquid works effectively as a piston compressing the gas in the vessel, hence the name &apos

New generation of free-piston shock tunnels

Science.gov (United States)

Morrison, W. R. B.; Stalker, R. J.; Duffin, J.

1990-01-01

Consideration is given to three free-piston driven hypersonic tunnels under construction that will greatly enhance existing test capabilities. The tunnel being built at Caltech will feature energy capabilities about 40 percent higher than those of the world's largest operational free-piston tunnel to date. The second tunnel under construction will allow full-size engine hardware at near-orbital speeds. The third facility is a high-performance expansion tube that will be capable of generating high enthalpy flows at speeds of up to 9 km/sec. It will provide flows with dissociation levels much lower than are attainable with a reflected shock tunnel, approaching actual flight conditions. A table shows the tunnels' characteristics.

A comparative reliability analysis of free-piston Stirling machines

Science.gov (United States)

Schreiber, Jeffrey G.

2001-02-01

A free-piston Stirling power convertor is being developed for use in an advanced radioisotope power system to provide electric power for NASA deep space missions. These missions are typically long lived, lasting for up to 14 years. The Department of Energy (DOE) is responsible for providing the radioisotope power system for the NASA missions, and has managed the development of the free-piston power convertor for this application. The NASA Glenn Research Center has been involved in the development of Stirling power conversion technology for over 25 years and is currently providing support to DOE. Due to the nature of the potential missions, long life and high reliability are important features for the power system. Substantial resources have been spent on the development of long life Stirling cryocoolers for space applications. As a very general statement, free-piston Stirling power convertors have many features in common with free-piston Stirling cryocoolers, however there are also significant differences. For example, designs exist for both power convertors and cryocoolers that use the flexure bearing support system to provide noncontacting operation of the close-clearance moving parts. This technology and the operating experience derived from one application may be readily applied to the other application. This similarity does not pertain in the case of outgassing and contamination. In the cryocooler, the contaminants normally condense in the critical heat exchangers and foul the performance. In the Stirling power convertor just the opposite is true as contaminants condense on non-critical surfaces. A methodology was recently published that provides a relative comparison of reliability, and is applicable to systems. The methodology has been applied to compare the reliability of a Stirling cryocooler relative to that of a free-piston Stirling power convertor. The reliability analysis indicates that the power convertor should be able to have superior reliability

Cylinder with differential piston for mass measurements

Energy Technology Data Exchange (ETDEWEB)

Bordeaşu, I.; Bălăşoiu, V. [Universitatea Politehnica din Timişoara, Timosoara (Romania); Hadă, A. [UniversitateaPolitehnicaBucureşti, Bucureşti (Romania); Popoviciu, M. [Academy of Romanian ScientistsTimişoara Branch (Romania)

2007-07-01

The paper presents a cylinder with differential piston, adapted for measuring the weight of fixed objects such as: fuel tanks (regardless of their capacity), bunkers and silos for all kind of materials, or mobile objects such as: automobiles, trucks, locomotives and railway cars. Although, the cylinder with differential piston is used on a large scale in hydraulic drive or hydraulic control circuits, till now it was not used as constituent part for weight measurements devices. The novelty of the present paper is precisely the use of the device for such purposes. Based on a computation algorithm, the paper presents the general design (assembly), of the device used for weighing important masses (1…. 100 tones). The fundamental idea consist in the fact that, a mass over 10 tones may be weighted with a helicoidally spring subjected to an axial force between 0 and 3000 N, with a deflection of about 30 mm. Simultaneously with the mechanical part, the electronic recording system is also described. The great advantage of the presented device consist in the fact that it can be used in heavy polluted atmosphere or difficult topographic conditions as a result of both the small dimensions and the protection systems adopted. Keywords: cylinder hydraulic with differential piston, hydrostatic pressure, measuring devices.

Development of a model capable of predicting the performance of piston ring-cylinder liner-like tribological interfaces

DEFF Research Database (Denmark)

Felter, C.L.; Vølund, A.; Imran, Tajammal

2010-01-01

Friction in the piston ring package (piston, piston rings, and liner) is a major source of power consumption in large two-stroke marine diesel engines. In order to improve the frictional and wear performance, knowledge about the tribological interface between piston rings and liner is needed...

Using the motor to monitor pump conditions

International Nuclear Information System (INIS)

Casada, D.

1996-01-01

When the load of a mechanical device being driven by a motor changes, whether in response to changes in the overall process or changes in the performance of the driven device, the motor inherently responds. For induction motors, the current amplitude and phase angle change as the shaft load changes. By examining the details of these changes in amplitude and phase, load fluctuations of the driven device can be observed. The usefulness of the motor as a transducer to improve the understanding of devices with high torque fluctuations, such as positive displacement compressors and motor-operated valves, has been recognized and demonstrated for a number of years. On such devices as these, the spectrum of the motor current amplitude, phase, or power normally has certain characteristic peaks associated with various load components, such as the piston stroke or gear tooth meshing frequencies. Comparison and trending of the amplitudes of these peaks has been shown to provide some indication of their mechanical condition. For most centrifugal pumps, the load fluctuations are normally low in torque amplitude, and as a result, the motor experiences a correspondingly lower level of load fluctuation. However, both laboratory and field test data have demonstrated that the motor does provide insight into some important pump performance conditions, such as hydraulic stability and pump-to-motor alignment. Comparisons of other dynamic signals, such as vibration and pressure pulsation, to motor data for centrifugal pumps are provided. The effects of inadequate suction head, misalignment, mechanical and hydraulic unbalance on these signals are presented

Using the motor to monitor pump conditions

Energy Technology Data Exchange (ETDEWEB)

Casada, D. [Oak Ridge National Lab., TN (United States)

1996-12-01

When the load of a mechanical device being driven by a motor changes, whether in response to changes in the overall process or changes in the performance of the driven device, the motor inherently responds. For induction motors, the current amplitude and phase angle change as the shaft load changes. By examining the details of these changes in amplitude and phase, load fluctuations of the driven device can be observed. The usefulness of the motor as a transducer to improve the understanding of devices with high torque fluctuations, such as positive displacement compressors and motor-operated valves, has been recognized and demonstrated for a number of years. On such devices as these, the spectrum of the motor current amplitude, phase, or power normally has certain characteristic peaks associated with various load components, such as the piston stroke or gear tooth meshing frequencies. Comparison and trending of the amplitudes of these peaks has been shown to provide some indication of their mechanical condition. For most centrifugal pumps, the load fluctuations are normally low in torque amplitude, and as a result, the motor experiences a correspondingly lower level of load fluctuation. However, both laboratory and field test data have demonstrated that the motor does provide insight into some important pump performance conditions, such as hydraulic stability and pump-to-motor alignment. Comparisons of other dynamic signals, such as vibration and pressure pulsation, to motor data for centrifugal pumps are provided. The effects of inadequate suction head, misalignment, mechanical and hydraulic unbalance on these signals are presented.

Development of a continuous-flow fluidic pump

International Nuclear Information System (INIS)

Robinson, S.M.

1985-08-01

A study was made of a fluidic pump which utilizes gas pistons, a venturi-like reverse-flow-diverter, and a planar Y-type flow junction to produce a continuous flow of liquid from a system containing no moving parts. The study included an evaluation of the system performance and of methods for controlling the stability of the fluidic system. A mathematical model of the system was developed for steady-state operation using accepted theories of fluid mechanics. Although more elaborate models are needed for detailed design and optimization of specific systems, the model determined some of the main factors controlling the system performance and will be used in the development of more accurate models. 49 refs., 39 figs., 9 tabs

LINC-NIRVANA piston control elements

Science.gov (United States)

Brix, Mario; Pott, Jörg-Uwe; Bertram, Thomas; Rost, Steffen; Borelli, Jose Luis; Herbst, Thomas M.; Kuerster, Martin; Rohloff, Ralf-Rainer

2010-07-01

We review the status of hardware developments related to the Linc-Nirvana optical path difference (OPD) control. The status of our telescope vibration measurements is given. We present the design concept of a feed-forward loop to damp the impact of telescope mirror vibrations on the OPD seen by Linc-Nirvana. At the focus of the article is a description of the actuator of the OPD control loop. The weight and vibration optimized construction of this actuator (aka piston mirror) and its mount has a complex dynamical behavior, which prevents classical PI feedback control from delivering fast and precise motion of the mirror surface. Therefore, an H-; optimized control strategy will be applied, custom designed for the piston mirror. The effort of realizing a custom controller on a DSP to drive the piezo is balanced by the outlook of achieving more than 5x faster servo bandwidths. The laboratory set-up to identify the system, and verify the closed loop control performance is presented. Our goal is to achieve 30 Hz closed-loop control bandwidth at a precision of 30 nm.

Computer Aided Design of Kaplan Turbine Piston with\tSolidWorks

Directory of Open Access Journals (Sweden)

Camelia Jianu

2010-10-01

Full Text Available The paper presents the steps for 3D computer aided design (CAD of Kaplan turbine piston made in SolidWorks.The present paper is a tutorial for a Kaplan turbine piston 3D geometry, which is dedicaded to the Parts Sketch and Parts Features design and Drawing Geometry and Drawing Annotation.

Stochastic stability assessment of a semi-free piston engine generator concept

Science.gov (United States)

Kigezi, T. N.; Gonzalez Anaya, J. A.; Dunne, J. F.

2016-09-01

Small engines, as power generators with low-noise and vibration characteristics, are needed in two niche application areas: as electric vehicle range extenders and as domestic micro Combined Heat and Power systems. A recent semi-free piston design known as the AMOCATIC generator fully meets this requirement. The engine potentially allows for high energy conversion efficiencies at resonance derived from having a mass and spring assembly. As with free-piston engines in general, stability and control of piston motion has been cited as the prime challenge limiting the technology's widespread application. Using physical principles, we derive in this paper two important results: an energy balance criterion and a related general stability criterion for a semi-free piston engine. Control is achieved by systematically designing a Proportional Integral (PI) controller using a control-oriented engine model for which a specific stability condition is stated. All results are presented in closed form throughout the paper. Simulation results under stochastic pressure conditions show that the proposed energy balance, stability criterion, and PI controller, operate as predicted to yield stable engine operation at fixed compression ratio.

A Free-Piston Linear Generator Control Strategy for Improving Output Power

Directory of Open Access Journals (Sweden)

Chi Zhang

2018-01-01

Full Text Available This paper presents a control strategy to improve the output power for a single-cylinder two-stroke free-piston linear generator (FPLG. The comprehensive simulation model of this FPLG is established and the operation principle is introduced. The factors that affect the output power are analyzed theoretically. The characteristics of the piston motion are studied. Considering the different features of the piston motion respectively in acceleration and deceleration phases, a ladder-like electromagnetic force control strategy is proposed. According to the status of the linear electric machine, the reference profile of the electromagnetic force is divided into four ladder-like stages during one motion cycle. The piston motions, especially the dead center errors, are controlled by regulating the profile of the electromagnetic force. The feasibility and advantage of the proposed control strategy are verified through comparison analyses with two conventional control strategies via MatLab/Simulink. The results state that the proposed control strategy can improve the output power by around 7–10% with the same fuel cycle mass.

Feasibility of free piston generation unit for electrical power provision

Energy Technology Data Exchange (ETDEWEB)

Harvey, R.; Roskilly, A.; Shaw, R.; French, C. [Newcastle Univ. (United Kingdom)

2000-07-01

Free piston linear engines offer the capability of providing power without the need to convert reciprocating motion into rotary motion. This allows for the utilisation of higher peak pressures during the combustion process and thus improves efficiency. The objective of this paper is to outline the potential benefits of a Free Piston Generator (FPG) and discuss the feasibility of this technology as a potential platform for electrical power provision. (authors)

H∞ Robust Control of a Large-Piston MEMS Micromirror for Compact Fourier Transform Spectrometer Systems

Directory of Open Access Journals (Sweden)

Huipeng Chen

2018-02-01

Full Text Available Incorporating linear-scanning micro-electro-mechanical systems (MEMS micromirrors into Fourier transform spectral acquisition systems can greatly reduce the size of the spectrometer equipment, making portable Fourier transform spectrometers (FTS possible. How to minimize the tilting of the MEMS mirror plate during its large linear scan is a major problem in this application. In this work, an FTS system has been constructed based on a biaxial MEMS micromirror with a large-piston displacement of 180 μm, and a biaxial H∞ robust controller is designed. Compared with open-loop control and proportional-integral-derivative (PID closed-loop control, H∞ robust control has good stability and robustness. The experimental results show that the stable scanning displacement reaches 110.9 μm under the H∞ robust control, and the tilting angle of the MEMS mirror plate in that full scanning range falls within ±0.0014°. Without control, the FTS system cannot generate meaningful spectra. In contrast, the FTS yields a clean spectrum with a full width at half maximum (FWHM spectral linewidth of 96 cm−1 under the H∞ robust control. Moreover, the FTS system can maintain good stability and robustness under various driving conditions.

H∞ Robust Control of a Large-Piston MEMS Micromirror for Compact Fourier Transform Spectrometer Systems.

Science.gov (United States)

Chen, Huipeng; Li, Mengyuan; Zhang, Yi; Xie, Huikai; Chen, Chang; Peng, Zhangming; Su, Shaohui

2018-02-08

Incorporating linear-scanning micro-electro-mechanical systems (MEMS) micromirrors into Fourier transform spectral acquisition systems can greatly reduce the size of the spectrometer equipment, making portable Fourier transform spectrometers (FTS) possible. How to minimize the tilting of the MEMS mirror plate during its large linear scan is a major problem in this application. In this work, an FTS system has been constructed based on a biaxial MEMS micromirror with a large-piston displacement of 180 μm, and a biaxial H∞ robust controller is designed. Compared with open-loop control and proportional-integral-derivative (PID) closed-loop control, H∞ robust control has good stability and robustness. The experimental results show that the stable scanning displacement reaches 110.9 μm under the H∞ robust control, and the tilting angle of the MEMS mirror plate in that full scanning range falls within ±0.0014°. Without control, the FTS system cannot generate meaningful spectra. In contrast, the FTS yields a clean spectrum with a full width at half maximum (FWHM) spectral linewidth of 96 cm -1 under the H∞ robust control. Moreover, the FTS system can maintain good stability and robustness under various driving conditions.

Heat Analysis of Liquid piston Compressor for Hydrogen Applications

DEFF Research Database (Denmark)

Kermani, Nasrin Arjomand; Rokni, Masoud

2014-01-01

A new hydrogen compression technology using liquid as the compression piston is investigated from heat transfer point of view. A thermodynamic model, simulating a single compression stroke, is developed to investigate the heat transfer phenomena inside the compression chamber. The model is develo......A new hydrogen compression technology using liquid as the compression piston is investigated from heat transfer point of view. A thermodynamic model, simulating a single compression stroke, is developed to investigate the heat transfer phenomena inside the compression chamber. The model...

Developmental Considerations on the Free-piston Stirling Power Convertor for Use in Space

Science.gov (United States)

Schreiber, Jeffrey G.

2007-01-01

Free-piston Stirling power conversion has been considered a candidate for radioisotope power systems for space for more than a decade. Prior to the free-piston Stirling architecture, systems were designed with kinematic Stirling engines with rotary alternators to convert heat to electricity. These systems were proposed with lightly loaded linkages to achieve the necessary life. When the free-piston configuration was initially proposed, it was thought to be attractive due to the relatively high conversion efficiency, acceptable mass, and the potential for long life and high reliability. These features have consistently been recognized by teams that have studied technology options for radioisotope power systems. Since free-piston Stirling power conversion was first considered for space power applications, there have been major advances in three general areas of development: demonstration of life and reliability, the success achieved by Stirling cryocoolers in flight, and the overall developmental maturity of the technology for both flight and terrestrial applications. Based on these advances, free-piston Stirling convertors are currently being developed for a number of terrestrial applications. They commonly operate with the power, efficiency, life, and reliability as intended, and much of the development now centers on system integration. This paper will summarize the accomplishments of free-piston Stirling power conversion technology over the past decade, review the status, and discuss the challenges that remain.

Development of a Proof of Concept Low Temperature Superfluid Magnetic Pump with Applications

Science.gov (United States)

Jahromi, Amir E.

State of the art particle and photon detectors such as Transition Edge Sensors (TES) and Microwave Kinetic Inductance Detectors (MKID) use large arrays of sensors or detectors for space science missions. As the size of these space science detectors increases, future astrophysics missions will require sub-Kelvin coolers over larger areas. This leads to not only increased cooling power requirements, but also a requirement for distributed sub-Kelvin cooling. Development of a proof of concept Superfluid Magnetic Pump is discussed in this work. This novel low temperature, no moving part pump can replace the existing bellows-piston driven 4He or 3He- 4He mixture compressor/circulators used in various sub Kelvin refrigeration systems such as dilution, Superfluid pulse tube, or active magnetic regenerative refrigerators. Due to its superior thermal transport properties this pump can also be used as a simple circulator of sub-Lambda 4He to distribute cooling over large surface areas. The pump discussed in this work was experimentally shown to produce a maximum flow rate of 440 mg/s (averaged over cycle), 665 mg/s (peak) and produced a maximum pressure difference of 2323 Pascal. This pump worked in an "ideal" thermodynamic state: The experimental results matched with the theoretical values predicted by a computer model. Pump curves were developed to map the performance of this pump. This successful demonstration will enable this novel pump to be put to test in suitable sub Kelvin refrigeration systems. Numerical modeling of an Active Magnetic Regenerative Refrigerator (AMRR) that uses the Superfluid Magnetic Pump (SMP) to circulate liquid 3He-4He through a magnetic regenerator is presented as a potential application of such a pump.

Analysis and control of a hybrid vehicle powered by free-piston energy converter

OpenAIRE

Hansson, Jörgen

2006-01-01

The introduction of hybrid powertrains has made it possible to utilise unconventional engines as primary power units in vehicles. The free-piston energy converter (FPEC) is such an engine. It is a combination of a free-piston combustion engine and a linear electrical machine. The main features of this configuration are high efficiency and a rapid transient response. In this thesis the free-piston energy converter as part of a hybrid powertrain is studied. One issue of the FPEC is the generati...

CAD/CAM/CAI Application for High-Precision Machining of Internal Combustion Engine Pistons

Directory of Open Access Journals (Sweden)

V. V. Postnov

2014-07-01

Full Text Available CAD/CAM/CAI application solutions for internal combustion engine pistons machining was analyzed. Low-volume technology of internal combustion engine pistons production was proposed. Fixture for CNC turning center was designed.

New computational and experimental stress analysis method for the design decision on optimum piston configuration. Piston oryoku no computer simulation to shinshikenho ni yoru keijo saitekika

Energy Technology Data Exchange (ETDEWEB)

Anno, N; Sugita, J [Honda R and D, Co. Ltd., Saitama (Japan)

1993-03-01

Piston troubles are mostly caused by cracks generating in each part of a piston. The finite element method (FEM) has been used for stress analysis of the piston, but has not been applied enough to design optimum configurations due to too much time for making models. In this study, stress analysis was carried out by the boundary element method (BEM), with which it is easy to make models and to change configurations, with various improvements. In addition, methods to execute a thermal load fatigue test and an actual running test to confirm analytical results were also improved. BEASY was used as basic software for analysis by BEM, and some improvements such as reduction of CPU time and optimization of memory using methods were carried out. It was easy to change configurations of the models by BEM, and the effect of the change in the piston boss configuration upon the stress agreed well with the actual test result. Design and evaluation of the optimum configuration has become easier by feedback of the results of the newly developed thermal load fatigue test to the analysis by BEM. 5 refs., 12 figs., 2 tabs.

Material Characterization and Real-Time Wear Evaluation of Pistons and Cylinder Liners of the Tiger 131 Military Tank

OpenAIRE

Saeed, Adil; Khan, Zulfiqar Ahmad; Hadfield, Mark; Davies, S.

2013-01-01

Material characterisation and wear evaluation of the original and replacement pistons and cylinder-liners of Tiger 131 is reported. Original piston and cylinder-liner were operative in the Tigers’ engine during WWII. The replacement piston and cylinder-liner were used as substitutes and were obtained after failure in two hours of operation in the actual engine. Material characterisation revealed that the original piston was aluminium silicon hypereutectic alloy whereas the replacement piston ...

Analytical prediction on the pump-induced pulsating pressure in a reactor coolant pipe

International Nuclear Information System (INIS)

Lee, K.B.; Im, I.Y.; Lee, S.K.

1992-01-01

An analytical method is presented for predicting the amplitudes of pump-induced fluctuating pressures in a reactor coolant pipe using a linear transformation technique which reduces a homogeneous differential equation with non-homogeneous boundary conditions into a nonhomogeneous differential equation with homogeneous boundary conditions. At the end of the pipe, three types of boundary conditions are considered-open, closed and piston-spring supported. Numerical examples are given for a typical reactor. Comparisons of measured pressure amplitudes in the pipe with model prediction are shown to be in good agreement for the forcing frequencies. (author)

Free Piston Problem for Isentropic Gas Dynamics

OpenAIRE

Takeno, Shigeharu

1995-01-01

We consider the existence of the generalized solution for a free piston problem for isentropic gas dynamics. By the compensated compactness theory, we can show that an approximate solution converges to a generalized solution.

The performance simulation of single cylinder electric power confined piston engine

Science.gov (United States)

Gou, Yanan

2017-04-01

A new type of power plant. i.e, Electric Power Confined Piston Engine, is invented by combining the free piston engine and the crank connecting rod mechanism of the traditional internal combustion engine. Directly using the reciprocating movement of the piston, this new engine converts the heat energy produced by fuel to electrical energy and output it. The paper expounds the working mechanism of ECPE and establishes the kinematics and dynamics equations. Furthermore, by using the analytic method, the ECPE electromagnetic force is solved at load cases. Finally, in the simulation environment of MARLAB, the universal characteristic curve is obtained in the condition of rotational speed n between 1000 r/min and 2400 r/min, throttle opening α between 30% and 100%.

Friction measurements in piston-cylinder apparatus using quartz-coesite reversible transition

Science.gov (United States)

Akella, J.

1979-01-01

The value of friction determined by monitoring piston displacement as a function of nominal pressure on compression and decompression cycles at 1273 K is compared with the friction value obtained by reversing the quartz-coesite transition at 1273 and 1073 K in a talc-glass-alsimag cell (Akella and Kennedy, 1971) and a low-friction salt cell (Mirwald et al., 1975). Quenching runs at 1273 K gave double values of friction of 0.25 GPa for the talc-glass-alsimag cell and 0.03 GPa for the salt cell. The piston-displacement technique gave somewhat higher values. Use of piston-displacement hysteresis loops in evaluating the actual pressure on a sample may lead to overestimates for decompression runs and underestimates for compression runs.

Adaptive sliding mode back-stepping pitch angle control of a variable-displacement pump controlled pitch system for wind turbines.

Science.gov (United States)

Yin, Xiu-xing; Lin, Yong-gang; Li, Wei; Liu, Hong-wei; Gu, Ya-jing

2015-09-01

A variable-displacement pump controlled pitch system is proposed to mitigate generator power and flap-wise load fluctuations for wind turbines. The pitch system mainly consists of a variable-displacement hydraulic pump, a fixed-displacement hydraulic motor and a gear set. The hydraulic motor can be accurately regulated by controlling the pump displacement and fluid flows to change the pitch angle through the gear set. The detailed mathematical representation and dynamic characteristics of the proposed pitch system are thoroughly analyzed. An adaptive sliding mode pump displacement controller and a back-stepping stroke piston controller are designed for the proposed pitch system such that the resulting pitch angle tracks its desired value regardless of external disturbances and uncertainties. The effectiveness and control efficiency of the proposed pitch system and controllers have been verified by using realistic dataset of a 750 kW research wind turbine. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Adaptive individual-cylinder thermal state control using piston cooling for a GDCI engine

Science.gov (United States)

Roth, Gregory T; Husted, Harry L; Sellnau, Mark C

2015-04-07

A system for a multi-cylinder compression ignition engine includes a plurality of nozzles, at least one nozzle per cylinder, with each nozzle configured to spray oil onto the bottom side of a piston of the engine to cool that piston. Independent control of the oil spray from the nozzles is provided on a cylinder-by-cylinder basis. A combustion parameter is determined for combustion in each cylinder of the engine, and control of the oil spray onto the piston in that cylinder is based on the value of the combustion parameter for combustion in that cylinder. A method for influencing combustion in a multi-cylinder engine, including determining a combustion parameter for combustion taking place in in a cylinder of the engine and controlling an oil spray targeted onto the bottom of a piston disposed in that cylinder is also presented.

Advanced Small Free-Piston Stirling Convertors for Space Power Applications

Science.gov (United States)

Wood, J. Gary; Lane, Neill

2004-02-01

This paper reports on the current status of an advanced 35 We free-piston Stirling convertor currently being developed under NASA SBIR Phase II funding. Also described is a further advanced and higher performance ~80 watt free-piston convertor being developed by Sunpower and Boeing/Rocketdyne for NASA under NRA funding. Exceptional overall convertor (engine plus linear alternator) thermodynamic performance (greater than 50% of Carnot) with specific powers around 100 We /kg appear reasonable at these low power levels.

Stochastic stability assessment of a semi-free piston engine generator concept

International Nuclear Information System (INIS)

Kigezi, T N; Anaya, J A Gonzalez; Dunne, J F

2016-01-01

Small engines, as power generators with low-noise and vibration characteristics, are needed in two niche application areas: as electric vehicle range extenders and as domestic micro Combined Heat and Power systems. A recent semi-free piston design known as the AMOCATIC generator fully meets this requirement. The engine potentially allows for high energy conversion efficiencies at resonance derived from having a mass and spring assembly. As with free-piston engines in general, stability and control of piston motion has been cited as the prime challenge limiting the technology's widespread application. Using physical principles, we derive in this paper two important results: an energy balance criterion and a related general stability criterion for a semi-free piston engine. Control is achieved by systematically designing a Proportional Integral (PI) controller using a control-oriented engine model for which a specific stability condition is stated. All results are presented in closed form throughout the paper. Simulation results under stochastic pressure conditions show that the proposed energy balance, stability criterion, and PI controller, operate as predicted to yield stable engine operation at fixed compression ratio. (paper)

Calculation of parameters of radial-piston reducer based on the use of functional semantic networks

Directory of Open Access Journals (Sweden)

Pashkevich V.M.

2016-12-01

Full Text Available The questions of сalculation of parameters of radial-piston reducer are considered in this article. It is used the approach which is based technologies of functional semantic networks. It is considered possibility applications of functional se-mantic networks for calculation of parameters of radial-piston reducer. Semantic networks to calculate the mass of the radial piston reducer are given.

Control scheme for power modulation of a free piston Stirling engine

Science.gov (United States)

Dhar, Manmohan

1989-01-01

The present invention relates to a control scheme for power modulation of a free-piston Stirling engine-linear alternator power generator system. The present invention includes connecting an autotransformer in series with a tuning capacitance between a linear alternator and a utility grid to maintain a constant displacement to piston stroke ratio and their relative phase angle over a wide range of operating conditions.

Translational velocity oscillations of piston generated vortex rings

Science.gov (United States)

Kumar, Manoj; Arakeri, J. H.; Shankar, P. N.

1995-11-01

Experimental results are presented that show that the translational velocities of piston generated vortex rings often undergo oscillations, similar to those recently discovered for drop generated rings. An attempt has been made to minimize uncertainties by utilizing both dye and hydrogen bubbles for visualization and carefully repeating measurements on the same ring and on different realizations under the same nominal piston conditions. The results unambiguously show that under most conditions, both for laminar and turbulent rings and for rings generated from pipes and orifices, the oscillations are present. The present results, together with the earlier results on drop generated rings, give support to the view that translational velocity oscillations are probably an inherent feature of translating vortex ring fields.

太阳能热泵系统中板式换热器模型分析%Plate Heat Exchanger Model Analysis of Solar Heat Pump System

Institute of Scientific and Technical Information of China (English)

芮胜军; 卢向华; 梁坤峰; 王志远

2013-01-01

　　The development of new energy and energy saving are two important ways of seeking energy way. The solar energy heat pump system has the vast development foreground with its characteristic of remarkable energy saving and environmental protection. Solar energy heat pump has the advantages of energy saving relative to air source heat pump. The evaporator and condenser of solar energy heat pump system were studied. The mathematical model of the application of solar heat pump system of the plate heat exchanger was discussed. And the calculation program was analyzed. The saving energy characteristic and existing problems of solar heat pump system were also discussed.%　　开发新能源和节能是寻求能源出路的两大重要途径，太阳能热泵供热系统以其显著的节能性和环保性具有广阔的发展前景。太阳能热泵相对空气源热泵具有明显的节能优势。以太阳能热泵系统应用的蒸发器和冷凝器为分析研究对象，讨论了板式换热器在太阳能热泵系统中应用的数学模型，并分析了其计算程序。讨论了太阳能热泵系统的节能特点及存在的问题。

Maximum Work of Free-Piston Stirling Engine Generators

Science.gov (United States)

Kojima, Shinji

2017-04-01

Using the method of adjoint equations described in Ref. [1], we have calculated the maximum thermal efficiencies that are theoretically attainable by free-piston Stirling and Carnot engine generators by considering the work loss due to friction and Joule heat. The net work done by the Carnot cycle is negative even when the duration of heat addition is optimized to give the maximum amount of heat addition, which is the same situation for the Brayton cycle described in our previous paper. For the Stirling cycle, the net work done is positive, and the thermal efficiency is greater than that of the Otto cycle described in our previous paper by a factor of about 2.7-1.4 for compression ratios of 5-30. The Stirling cycle is much better than the Otto, Brayton, and Carnot cycles. We have found that the optimized piston trajectories of the isothermal, isobaric, and adiabatic processes are the same when the compression ratio and the maximum volume of the same working fluid of the three processes are the same, which has facilitated the present analysis because the optimized piston trajectories of the Carnot and Stirling cycles are the same as those of the Brayton and Otto cycles, respectively.

Development of an accelerating piston implosion-driven launcher

International Nuclear Information System (INIS)

Huneault, J; Loiseau, J; Higgins, A J

2014-01-01

The ability to soft-launch projectiles to velocities exceeding 10 km/s is of interest for a number of scientific fields, including orbital debris impact testing and equation of state research. Current soft-launch technologies have reached a performance plateau below this operating range. In the implosion-driven launcher (ILD) concept, explosives are used to dynamically compress a light driver gas to significantly higher pressures and temperatures than the propellant of conventional light-gas guns. The propellant of the IDL is compressed through the linear implosion of a pressurized tube. The imploding tube behaves like a piston which travels into the light gas at the explosive detonation velocity, thus forming an increasingly long column of shock-compressed gas which can be used to propel a projectile. The McGill designed IDL has demonstrated the ability to launch a 0.1-g projectile to 9.1 km/s. This work will focus on the implementation of a novel launch cycle in which the explosively driven piston is accelerated in order to gradually increase driver gas compression, thus maintaining a relatively constant projectile driving pressure. The theoretical potential of the concept as well as the experimental development of an accelerating piston driver will be examined.

A Space Cam Mechanism for Power Transmission of an Opposite-cylinder Piston Engine

Directory of Open Access Journals (Sweden)

Zhang Haoyue

2015-01-01

Full Text Available For the purpose of improving the engine’s power density, we put forward a new type of power transmission mechanism which is used for opposed-cylinder engine. The gas pressure acts on the cam through the piston and push rod, and the spindle rotation of external is driven by the cam. The design of spatial cam work surface is completed by using the enveloping theory of a family of space curves, the force between roller and cam is analyzed using dynamic analysis software. Under the condition of equal number, size and stroke of piston, the new one with larger power density is more compact in structure than the traditional power transmission mechanism, and the reaction force on either side of the main shaft and the acting force between pistons and cylinders are smaller than those in traditional one, which prolongs the service life of the pistons.

Heavy duty composite piston for Euro 6 and beyond; Verschraubte Nutzfahrzeugkolben fuer die Euro-6-Norm und folgende

Energy Technology Data Exchange (ETDEWEB)

Scharp, Rainer [Mahle GmbH, Stuttgart (Germany). Konstruktion Stahlkolben Europa Produktlinie Kolbensysteme

2009-02-15

Composite pistons have been the state of the art in large bore engines - such as large marine engines - since the 1960s. The thermal and mechanical load of these engines is typically higher than the load of truck engines. Additionally composite pistons are being used for large bore engines because of their durability and reliability. Based on the experience with composite pistons for large bore engines, Mahle was able to transfer this reliable bolting technology to steel pistons for commercial vehicles, the 'MonoXcomp' piston. (orig.)

Extended Analytic Linear Model of Hydraulic Cylinder With Respect Different Piston Areas and Volumes

OpenAIRE

Petr KOŇAŘÍK

2009-01-01

Standard analytic linear model of hydraulic cylinder usually comes from assumptions of identical action piston areas on both sides of hydraulic cylinder (double piston rod) and suitable operation point, which is usually chosen in the middle of piston. By reason of that volumes inside of cylinder are than same. Moreover for control of that arrangement of hydraulic cylinder, usually controlled by 4/3 servovalve, the same mount of flows comes in and comes out to each of chambers of hydraulic cyl...

Optimal paths of piston motion of irreversible diesel cycle for minimum entropy generation

Directory of Open Access Journals (Sweden)

Ge Yanlin

2011-01-01

Full Text Available A Diesel cycle heat engine with internal and external irreversibility’s of heat transfer and friction, in which the finite rate of combustion is considered and the heat transfer between the working fluid and the environment obeys Newton’s heat transfer law [q≈ Δ(T], is studied in this paper. Optimal piston motion trajectories for minimizing entropy generation per cycle are derived for the fixed total cycle time and fuel consumed per cycle. Optimal control theory is applied to determine the optimal piston motion trajectories for the cases of with piston acceleration constraint on each stroke and the optimal distribution of the total cycle time among the strokes. The optimal piston motion with acceleration constraint for each stroke consists of three segments, including initial maximum acceleration and final maximum deceleration boundary segments, respectively. Numerical examples for optimal configurations are provided, and the results obtained are compared with those obtained when maximizing the work output with Newton’s heat transfer law. The results also show that optimizing the piston motion trajectories could reduce engine entropy generation by more than 20%. This is primarily due to the decrease in entropy generation caused by heat transfer loss on the initial portion of the power stroke.

A study on the development of engineering plastic piston used in the shock absorber

Science.gov (United States)

Kim, Young-Ho; Bae, Won-Byong; Lim, Dong-Ju; Suh, Yun-Soo

1998-08-01

A piston is an important component of the shock absorber which determines comfortable riding and handling. Conventional piston is made of metal powder that is pressed in a mold, and then sintered at high temperatures below the melting point before machining processes such as drilling, sizing and teflon banding. This study aims at cutting down cost and weight, and improving the process by replacing the traditional sintering process used for manufacturing the shock absorber with the injection molding process adopting engineering plastics as raw material. To analyze the injection molding process, we used the commercial program, MOLDFLOW, and obtained an optimal combination of the process parameters. In addition, by comparing the engineering plastic piston with the metal powder piston through the formability and the performance experiments, we confirmed the availability of this alternative process suggested.

CRANK-PISTON MODEL OF INTERNAL COMBUSTION ENGINE USING CAD/CAM/CAE IN THE MSC ADAMS

Directory of Open Access Journals (Sweden)

Michał BIAŁY

2017-03-01

Full Text Available The article presents the modeling and simulation of the crank-piston model of internal combustion engine. The object of the research was the engine of the vehicle from the B segment. The individual elements of the gasoline engine were digitizing using the process of reverse engineering. After converting the geometry, assembling was imported to MSC Adams software. The crank-piston system was specified by boundary conditions of piston forces applied on the pistons crowns. This force was obtain from the cylinder pressure recorded during the tests, that were carried out on a chassis dynamometer. The simulation studies allowed t determine the load distribution in a dynamic state for the selected kinematic pairs.

Cavitation erosion of silver plated coating at different temperatures and pressures

Energy Technology Data Exchange (ETDEWEB)

Hattori, Shuji; Motoi, Yoshihiro [Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fuku-shi, Fukui 910-8507 (Japan); Kikuta, Kengo; Tomaru, Hiroshi [IHI Corperation, TOYOSU IHI BUILDING, 1-1, Toyosu 3-chome, Koto-ku, Tokyo 1358710 (Japan)

2014-04-11

Cavitation often occurs in inducer pumps used for space rockets. Silver plated coating on the inducer liner faces the damage of cavitation. Therefore, it is important to study about the cavitation erosion resistance for silver plated coating at several operating conditions in the inducer pumps. In this study, the cavitation erosion tests were carried for silver plated coating in deionized water and ethanol at several liquid temperatures (273K–400K) and pressures (0.10MPa–0.48MPa). The mass loss rate is evaluated in terms of thermodynamic parameter Σ proposed by Brennen [9], suppression pressure p–p{sub v} (p{sub v}: saturated vapor pressure) and acoustic impedance ρc (ρ: density and c: sound speed). Cavitation bubble behaviors depending on the thermodynamic effect and the liquid type were observed by high speed video camera. The mass loss rate is formulated by thermodynamic parameter Σ, suppression pressure p–p{sub v} and acoustic impedance ρc.

76 FR 3128 - Intent to Grant Patent License

Science.gov (United States)

2011-01-19

... Displacement Hydraulic Pump/Motor. 7,108,016 Lightweight Low September 19, 2006. Permeation Piston-in- Sleeve... Pump/ September 29, 2006. Motor. 12/156,734 Piston-in-Sleeve June 4, 2008. Hydraulic Pressure... Methods for Safe April 21, 2010. Operation of Hydraulic Hybrid Vehicles with Over-Center Pump/Motors. 12...

Hydrodynamic model experiments for stabilized liquid liners with annular piston drive

International Nuclear Information System (INIS)

Burton, R.L.; Turchi, P.J.; Jenkins, D.J.; Cooper, A.L.

1977-01-01

The achievement of megagauss-level magnetic fields by flux compression using controlled liquid liner implosions will be studied in the LINUS-O experiments. This paper reports on experimental studies of the rotating liquid liner at lower energy density, using a one-third scale model with water as the liner material. Radial implosion of the free inside surface of the liquid is achieved by axial displacement of an annular piston, driven by helium. Azimuthally symmetric, repetitive implosion-reexpansion cycles have been demonstrated, with area compressions of over a hundred. The apparatus has also been used to investigate other problems inherent in the annular piston geometry, including piston guidance, seals, z-dependence of the imploding free surface trajectory, and Rayleigh-Taylor instability of the free surface. Methods for r-z plane tailoring of the free surface to provide three-dimensional payload compression are considered

Piston rod seal for a Stirling engine

Science.gov (United States)

Shapiro, Wilbur

1984-01-01

In a piston rod seal for a Stirling engine, a hydrostatic bearing and differential pressure regulating valve are utilized to provide for a low pressure differential across a rubbing seal between the hydrogen and oil so as to reduce wear on the seal.

New Universal Tribometer as Pin or Ball-on-Disc and Reciprocating Pin-on-Plate Types

Directory of Open Access Journals (Sweden)

H. Kaleli

2016-06-01

Full Text Available The present paper contains a description of a new Universal Tribometer design which enables simulation of different contact and test types such as pin-on-disc, ball-on-disc and linear reciprocating tests. There are many models of wear Tribometer in the world market. These devices are manufactured by various companies abroad and are imported to our country. Cost of this devices start from 50.000 euros and goes to hundreds of thousands of euros. One of the most commonly used of this device is Reciprocating Pin-on-Plate Tribo Test Machine. This wear tester is produced at a low limited cost within the KAP (Scientifical Research Project Coordinator of Yıldız Technical University. The test machine can work including three types of Tribotest rigs (Reciprocating Pin-on-Plate, Pin-on-Disc and Ball-on-Disc. It is designed to operate also at high temperatures up to 500 ˚C. The new piece of equipment allows instrumented tribological testing of piston ring and cylinder liner samples at low and high temperatures and boundary lubrication conditions of any typical gasoline or Diesel engines. Some friction results were shown in boundary lubricating conditions between piston ring and cylinder liner sliding pairs describing Tribotest machine is driven by AC servo motor which is more accurate than DC motor.

Modelling of Split Condenser Heat Pump with Limited Set of Plate Heat Exchanger Dimensions

DEFF Research Database (Denmark)

Christensen, Stefan Wuust; Elmegaard, Brian; Markussen, Wiebke Brix

2017-01-01

in parallel to different temperature levels, whereas only one stream is heated in a THP. The length/width ratio of the plate heat exchangers on the high pressure side of a SCHP was investigated to find the optimal plate dimensions with respect to minimum area of the heat exchangers. The total heat exchanger...... area was found to decrease with an increasing length/width ratio of the plates. The marginal change in heat exchanger area was shown to be less significant for heat exchangers with high length/width ratios. In practice only a limited number of plate dimensions are available and feasible...... in the production. This was investigated to find the practical potential of a SCHP compared to a THP. Using plates optimized for a SCHP in a THP, the total required heat exchanger area increased by approximately 100% for the conditions investigated in this study, indicating that available plate dimensions influence...

Continuing Development for Free-Piston Stirling Space Power Systems

Science.gov (United States)

Peterson, Allen A.; Qiu, Songgang; Redinger, Darin L.; Augenblick, John E.; Petersen, Stephen L.

2004-02-01

Long-life radioisotope power generators based on free-piston Stirling engines are an energy-conversion solution for future space applications. The high efficiency of Stirling machines makes them more attractive than the thermoelectric generators currently used in space. Stirling Technology Company (STC) has been developing free-piston Stirling machines for over 30 years, and its family of Stirling generators is ideally suited for reliable, maintenance-free operation. This paper describes recent progress and status of the STC RemoteGen™ 55 W-class Stirling generator (RG-55), presents an overview of recent testing, and discusses how the technology demonstration design has evolved toward space-qualified hardware.

Design and preliminary test of heat isulated pistons for a diesel engine. Dieselmoottorin laempoeeristetyn maennaen suunnittelu ja esikokeet

Energy Technology Data Exchange (ETDEWEB)

Kojonen, M.; Pitkaenen, J.; Kleimola, M.

1989-01-01

This report describes the ceramic heat insulation of the combustion chamber of high speed diesel engines and results of tests carried out in one cylinder of a four-cylinder engine with two different heat insulated experimental pistons. The work is part of the research programme called 'Ceramic applications in mechanical engineering'. The research work is being done at Helsinki University of Technology in the Internal Combustion Engine Laboratory and is financed mainly by the Technology Development Centre TEKES. Valmet Oy Linnavuori Works has contributed to the work by supplying the test engine for the research. In the short literature review presented first. advantages of the combustion chamber insulation and design solutions for heat flow prevention are described. In the experimental part of the research two different experimental pistons with ceramic combustion chamber were designed for the Valmet 411 DSJ diesel engine with direct injection. One of the pistons was furnished with a steel piston head, which was fastened to the aluminium piston body. The ceramic combustion chamber bowl was inserted into the steel head. The other piston was developed from Kymenite cast iron, which made it possible to insert the piston bowl direct into the piston body. The aim of the experiments was to clarify the function ability and the necessary clearances of the piston constructions and to indicate the insulation ability of the combustion chamber by means of the temperature measurements of the cylinder liner, cylinder head and exhaust gas temperature.

Directionality of sperm whale sonar clicks and its relation to piston radiation theory

DEFF Research Database (Denmark)

Beedholm, K.; Møhl, Bertel

2006-01-01

This paper investigates the applicability to sperm whales of the theory of sound radiating from a piston. The theory is applied to a physical model and to a series of sperm whale clicks. Results show that wave forms of off-axis signals can be reproduced by convolving an on-axis signal...... with the spatial impulse response of a piston. The angle of a recorded click can be estimated as the angle producing the spatial impulse response that gives the best match with the observation when convolved with the on-axis wave form. It is concluded that piston theory applies to sperm whale sonar click emission....

Aluminium matrix heterophase composites for air compressor pistons

Directory of Open Access Journals (Sweden)

M.Dyzia

2011-04-01

Full Text Available The article presents the results of surface test of composite shaped in the permanent mould casting process. As part of the research anddevelopment project realized in the Department of Materials Technology at the Silesian University of Technology, a pilot plant scale stand was built to manufacture of more than 50 kg suspensions in a single technological cycle. Made in industrial conditions castings to form in the five inner core mould mounted in GM110 permanent mould casting machine confirmed the possibility of the shaping the composite pistons. Castings made from composite suspension AlSi7Mg/SiC and AlSi7Mg/SiC + Cg according to the technology procedure were classified as correct and devoted to the proper machining forming working surfaces of the piston to the air compressor. Comparative tests were performed for the casting of unreinforced AlSi7Mg alloy and composite castings. To assess the ability to fill the mold cavity and the accuracy of mapping used in contour shape FRT analysis of the distance between the grooves on the surface of the piston skirt. Studies have confirmed the differences in the fluidity of alloy matrix and composites suspensions. The difference in the accuracy of the dimensional mapping mould does not disqualify of composite materials, all castings are classified as correct and used for machining.

Housing maintenance of primary cooling pump I of Kartini reactor

International Nuclear Information System (INIS)

Agung Nugroho; Wahyu Imam W

2013-01-01

Housing maintenance of Primary Cooling Pump have been done with purpose to enhance capability of fluid block and stopping leakage. The procedures of modification are follow: Replace mechanical seal type Nock 560 – 1 ½'' by mechanical seal type Nock 560 - 38, modification gland plate/housing with to lathe the diameter of gland plate/housing from diameter of 54 mm to 60 mm, in size setting-up mechanical seal, alignment and then function test. The result of the modification are: mechanical seal has been installed, housing has been modified, and the leakage of primary cooling water has been repaired and operated properly. Conclusion of the maintenance are the primary cooling water pump is working well, because the primary cooling water is not leakage any more. (author)

Experimental investigation of hinged and spring loaded rolling piston compressors pertaining to a turbo rotary engine

International Nuclear Information System (INIS)

Okur, Melih; Akmandor, Ibrahim Sinan

2011-01-01

Hinged rolling piston compressor of a new thermodynamic cycle Pars engine promises high performance figures such as single stage high compression levels and higher volume flow discharge with competitively low input power and torque. The pumping characteristic of the present engine compressor unit has been increased by the implementation of a spring less vane configuration. The reciprocating vane which is usually operated by spring compression in air conditioning and refrigeration unit has been replaced by a hinge vane mechanism. At high speeds, the conventional spring loaded vane which is forced against the eccentrically moving rotor periphery does disconnect and starts rocking. With the new configuration, this mishap has been eliminated and subsequently resulting compressor pressure leaks have been avoided. Compressor experiments have been carried out at predetermined rotor speeds and compressed volume flow amounts and required shaft powers have been measured and derived accordingly. Experimentally determined pressure-volume relations have been compared with isentropic, isothermal, isochoric compressions as well as isobaric process. It is seen that at lower speeds, hinged vane compression is half way between isentropic and isochoric compressions whereas at high speed the compression process approaches further isochoric compression behavior. The isentropic compression efficiency of the hinged vane compressor is around 85% for pressures reaching 9 atm. - Research highlights: → Volume flow rate of rotary vane compressor unit has been increased by a hinged vane mechanism. → Hinged compressor pressure output is almost twice the performance of a spring loaded compressor. → The slipping and rocking of the spring loaded vane against the rolling piston have been eliminated.

Free piston linear generator in comparison to other range-extender technologies

OpenAIRE

Virsik, Roman; Heron, Alex

2013-01-01

The free piston linear generator is a new range-extender technology. It converts chemical energy into electrical energy by means of a combustion process and linear generator. Thereby the technology aims to have better properties than other range extenders. Therefore this publication deals with the explanation of the concept and the characteristics of a free piston linear generator and a comparison to other technologies. In order to compare the range extender systems, fuel cells, micro gas tur...

Experimental Investigation of the Motion and Shape of Flexible Objects near a Pump Inlet

DEFF Research Database (Denmark)

Jensen, Anna Lyhne; Abou Ackl, Raja; Gerlach, Stefan

Previous investigations of clogging effects in waste water pumps have focused on the impact of pumping contaminated water on the pump performance, as well as the influence of the operating point on the location of clogged material in the pump and in the pumping system. The present work aims...... to characterise the dynamics of flexible material entering a rotating impeller. Experiments are carried out in a wet pit located in the Department of Fluid System Dynamics in TU Berlin. The wet pit is modified with an acrylic plate placed at the bottom of the pit, enabling visual access to the suction side...

Theoretical and experimental studies of a magnetically actuated valveless micropump

International Nuclear Information System (INIS)

Ashouri, Majid; Shafii, Mohammad Behshad; Moosavi, Ali

2017-01-01

This paper presents the prototype design, fabrication, and characterization of a magnetically actuated micropump. The pump body consists of three nozzle/diffuser elements and two pumping chambers connected to the ends of a flat-wall pumping cylinder. A cylindrical permanent magnet placed inside the pumping cylinder acts as a piston which reciprocates by using an external magnetic actuator driven by a motor. The magnetic piston is covered by a ferrofluid to provide self-sealing capability. A prototype composed of three bonded layers of polymethyl-methacrylate (PMMA) has been fabricated. Water has been successfully pumped at pressures of up to 750 Pa and flow rates of up to 700 µ l min −1 while working at the piston actuation frequency of 4 and 5 Hz, respectively. 3D numerical simulations are also carried out to study the performance of the pump. The best experimental and numerical volumetric efficiency of the pump are about 7 and 8%, respectively, at the piston speed of 0.03 m s −1 . The contactless external actuation feature of the design enables integration of the pump with other PMMA-based microfluidic systems with low cost and disposability. (paper)

Test results of pre-production prototype distributed ion pump design for the PEP-II Asymmetric B-Factory collider

Energy Technology Data Exchange (ETDEWEB)

Holdener, F.R.; Behne, D.; Hathaway, D. [and others

1995-04-24

We have built and tested a plate-type pre-production distributed Ion Pump (DIP) for the PEP-II B-Factory High Energy Ring (HER). The design has been an earlier design to use less materials and to costs. Penning cell hole sizes of 15, 18, and 21 mm have been tested in a uniform magnetic field of 0.18 T to optimize pumping speed. The resulting final DIP design consisting of a 7-plate, 15 mm basic cell size anode was magnetic field of the HER dipole. A description of the final optimized DIP design will be presented along with the test results of the pumping speed measurements.

A thermodynamic study for the optimization of stable operation of free piston Stirling engines

Energy Technology Data Exchange (ETDEWEB)

Rogdakis, E.D.; Bormpilas, N.A.; Koniakos, I.K. [National Technical Univerisity, Athens (Greece). Dept. of Mechanical Engineering

2004-03-01

One of the most novel applications of the Stirling cycle is in the free piston configuration that was initially designed by W. Beale. In free piston Stirling engines (FPSEs), there are no mechanical linkages coupling the pistons or displacers, the motions of the reciprocating components follow the working gas pressure variations. Fillipo de Monte and G. Benvenuto have recently proposed a linearization technique of the dynamic balance equations. The aim of this paper is to predict the thermodynamic conditions for stable operation of FPSEs and their modeling. The equations of the angular velocity are solved analytically in terms of the working gas mass and the displacer-piston phase angle of the machine. Using the criterion of stable engine cyclic steady operation, a mathematically rigorous form is obtained for the main parameters of the engine. Furthermore, for simplicity reasons, thermodynamic magnitudes are obtained using the Schmidt analysis (isothermal model). (author)

A thermodynamic study for the optimization of stable operation of free piston Stirling engines

International Nuclear Information System (INIS)

Rogdakis, E.D.; Bormpilas, N.A.; Koniakos, I.K.

2004-01-01

One of the most novel applications of the Stirling cycle is in the free piston configuration that was initially designed by W. Beale. In free piston Stirling engines (FPSEs), there are no mechanical linkages coupling the pistons or displacers, the motions of the reciprocating components follow the working gas pressure variations. Fillipo de Monte and G. Benvenuto have recently proposed a linearization technique of the dynamic balance equations. The aim of this paper is to predict the thermodynamic conditions for stable operation of FPSEs and their modeling. The equations of the angular velocity are solved analytically in terms of the working gas mass and the displacer-piston phase angle of the machine. Using the criterion of stable engine cyclic steady operation, a mathematically rigorous form is obtained for the main parameters of the engine. Furthermore, for simplicity reasons, thermodynamic magnitudes are obtained using the Schmidt analysis (isothermal model)

Cogging force investigation of a free piston permanent magnet linear generator

Science.gov (United States)

Abdalla, I. I.; Zainal, A. E. Z.; Ramlan, N. A.; Firmansyah; Aziz, A. R. A.; Heikal, M. R.

2017-10-01

Better performance and higher efficiency of the vehicles can be achieved by using free piston engine, in which the piston is connected directly to the linear generator and waiving of any mechanical means. The free piston engine has the ability to overcome or reduce many of the challenges, such as the carbon dioxide (CO2) emission and fossil fuel consumption. The cogging force produces undesired vibration and acoustic noise in the generator. However, the cogging force must be minimized as much as possible, in order to have a high performance. This paper studies the effects of ferromagnetic materials on the cogging force of the permanent magnet linear generator (PMLG) to be used in a free piston engine using nonlinear finite-element analysis (FEA) under ANSYS Maxwell. The comparisons have been established for the cogging force of the PMLG under various translator velocities and three different ferromagnetic materials for the stator core, namely, Silicon Steel laminations, Mild Steel and Somaloy. It has been shown that the PMLG with a stator core made of Somaloy has a lower cogging force among them. Furthermore, the induced voltage of the PMLG at different accelerations has been studied. It is found that the PMLG with Mild Steel and Somaloy, respectively give larger induced voltage. Moreover, as the translator speed increase the induced voltage increased.

Lubrication of Piston Rings in Large 2–and 4–stroke Diesel Engines

DEFF Research Database (Denmark)

Felter, Christian Lotz

Piston rings are vital components of any internal combustion engine, and their performance affect important properties such as frictional losses, oil consumption, and wear of parts. This thesis deals with the lubrication of piston rings from a theoretical point of view. Predictions are made using...

Aircraft Piston Engine Exhaust Emission Symposium

Science.gov (United States)

1976-01-01

A 2-day symposium on the reduction of exhaust emissions from aircraft piston engines was held on September 14 and 15, 1976, at the Lewis Research Center in Cleveland, Ohio. Papers were presented by both government organizations and the general aviation industry on the status of government contracts, emission measurement problems, data reduction procedures, flight testing, and emission reduction techniques.

Mathematical Model of Piston Ring Sealing in Combustion Engine

Directory of Open Access Journals (Sweden)

Koszałka Grzegorz

2015-01-01

Full Text Available This paper presents a mathematical model of piston-rings-cylinder sealing (TPC of a combustion engine. The developed model is an itegrated model of gas flow through gaps in TPC unit, displacements and twisting motions of piston rings in ring grooves as well as generation of oil film between ring face surfaces and cylinder liner. Thermal deformations and wear of TPC unit elements as well as heat exchange between flowing gas and surrounding walls, were taken into account in the model. The paper contains descriptions of: assumptions used for developing the model, the model itself, its numerical solution as well as its computer application for carrying out simulation tests.

Critical needs for piston engine overhaul centre in Malaysia

Science.gov (United States)

Khairuddin, M. H.; Yahya, M. Y.; Johari, M. K.

2017-12-01

Piston engine overhaul centre (PEOC) is the branch of aviation Maintenance, Repair and Overhaul (MRO) providers, which plays a pivotal role in maintaining the fleet of business and commercial aircraft in the world. The centre typically offers three main MRO capabilities: airframe, engine and component services. Companies holding a PEOC(s) are all subjected to stringent procedures and conditions regulated and audited by the International Civil Aviation Organization. Currently, piston engine maintenance and repair for Asian countries is conducted only in Singapore. The focus of this study is to establish the needs for a PEOC in Malaysia, which will cater almost all small local aircraft companies such as transport and flying school companies.

Novel Tribotester for Cylinder Liner/Piston Ring Contacts of Two Stroke Marine Diesel Engines

DEFF Research Database (Denmark)

Pedersen, Michael Torben; Imran, Tajammal; Klit, Peder

2009-01-01

A good tribological description for the cylinder liner and piston ring materials is always desired in order to achieve an improved combination of the materials. The piston ring package in a two-stroke-diesel engine operates in three lubrication regimes and the materials must be characterized...... in relation to this before a final selection is made. A tribo-test-apparatus is developed to study the tribological performance and to rank the different combinations of cylinder liner and piston ring materials of two stroke marine diesel engines. The test apparatus is based on the block-on-ring principle...

Effects of Scavenging System Configuration on In-Cylinder Air Flow Organization of an Opposed-Piston Two-Stroke Engine

Directory of Open Access Journals (Sweden)

Fukang Ma

2015-06-01

Full Text Available In-cylinder air flow is very important from the point of view of mixture formation and combustion. In this direction, intake chamber structure and piston crown shape play a very crucial role for in-cylinder air pattern of opposed-piston two-stroke (OP2S engines. This study is concerned with the three-dimensional (3D computational fluid dynamics (CFD analysis of in-cylinder air motion coupled with the comparison of predicted results with the zero-dimensional (0D parametric model. Three configurations viz., a flat piston uniform scavenging chamber, a flat piston non-uniform scavenging chamber and a pit piston non-uniform scavenging chamber have been studied. 0D model analysis of in-cylinder air flow is consistent with 3D CFD simulation. It is concluded that a pit piston non-uniform scavenging chamber is the best design from the point of view of tumble ratio, turbulent kinetic energy and turbulent intensity, which play very important roles in imparting proper air motion. Meanwhile a flat piston uniform scavenging chamber can organize a higher swirl ratio and lower tumble ratio which is important to improve the scavenging process.

Hot-rolled Process of Multilayered Composite Metal Plate

Directory of Open Access Journals (Sweden)

YU Wei

2017-02-01

Full Text Available For multi-layer plate, it is a difficult problem to increase product yield rate and improve bonding interface quality. A high yield hot-rolled method of multilayered plate was proposed. The raw strips and plate were fixed by argon arc welding. The combined billet was put into a metal box and vacuum pumped, and then heated and rolled by multi passes at the temperature of 1000-1200℃. The 67 layered plate with the thickness of 2.5mm was successfully produced. The interfacial microstructures and diffusion behavior were investigated and analyzed by optical microscopy and scan electronic microscopy. The tensile and shear strength were tested,and the shear fractures were analyzed. The results show that the multilayered plate yield rate is more than 90% by two steps billet combination method and rolling process optimization. The good bonding interface quality is obtained, the shear strength of multilayered plate reaches 241 MPa. Nickel interlayer between 9Cr18 and 1Cr17 can not only prevent the diffusion of carbon, but also improve the microstructure characteristics.

Final design of a free-piston hydraulic advanced Stirling conversion system

Science.gov (United States)

Wallace, D. A.; Noble, J. E.; Emigh, S. G.; Ross, B. A.; Lehmann, G. A.

1991-01-01

Under the US Department of Energy's (DOEs) Solar Thermal Technology Program, Sandia National Laboratories is evaluating heat engines for solar distributed receiver systems. The final design is described of an engineering prototype advanced Stirling conversion system (ASCS) with a free-piston hydraulic engine output capable of delivering about 25 kW of electric power to a utility grid. The free-piston Stirling engine has the potential for a highly reliable engine with long life because it has only a few moving parts, has noncontacting bearings, and can be hermetically sealed. The ASCS is designed to deliver maximum power per year over a range of solar input with a design life of 30 years (60,000 h). The system includes a liquid Nak pool boiler heat transport system and a free-piston Stirling engine with high-pressure hydraulic output, coupled with a bent axis variable displacement hydraulic motor and a rotary induction generator.

Final design of a free-piston hydraulic advanced Stirling conversion system

Science.gov (United States)

Wallace, D. A.; Noble, J. E.; Emigh, S. G.; Ross, B. A.; Lehmann, G. A.

Under the US Department of Energy's (DOEs) Solar Thermal Technology Program, Sandia National Laboratories is evaluating heat engines for solar distributed receiver systems. The final design is described of an engineering prototype advanced Stirling conversion system (ASCS) with a free-piston hydraulic engine output capable of delivering about 25 kW of electric power to a utility grid. The free-piston Stirling engine has the potential for a highly reliable engine with long life because it has only a few moving parts, has noncontacting bearings, and can be hermetically sealed. The ASCS is designed to deliver maximum power per year over a range of solar input with a design life of 30 years (60,000 h). The system includes a liquid Nak pool boiler heat transport system and a free-piston Stirling engine with high-pressure hydraulic output, coupled with a bent axis variable displacement hydraulic motor and a rotary induction generator.

Overview of free-piston Stirling engine technology for space power application

International Nuclear Information System (INIS)

Slaby, J.G.

1987-01-01

An overview is presented of the National Aeronautics and Space Administration (NASA) Lewis Research Center (LeRC) free-piston Stirling engine activities directed toward space-power application. Free-piston Stirling technology is applicable for both solar and nuclear powered systems. As such, the NASA Lewis Research Center serves as the project office to manage the newly initiated SP-100 Advanced Technology program. This program provides the technology push for providing significant component and subsystem options for increased efficiency, reliability and survivability, and power output growth at reduced specific mass. One of the major elements of the program is the development of advanced power conversion of which the Stirling cycle is a viable candidate. Under this program the status of the 25 kWe opposed-piston Space Power Demonstrator Engine (SPDE) is presented. Included in the SPDE discussion are initial differences between predicted and experimental power outputs and power output influenced by variations in regenerators

Edge plasma control: Particle channeling in Tore Supra pump limiter and ergodic divertor

International Nuclear Information System (INIS)

Ghendrih, P.; Samain, A.; Grosman, A.; Capes, H.; Morera, J.P.

1989-01-01

Improved pumping efficiency can be achieved on Tore Supra by channeling process for particles, i.e. channeling of neutrals in the throat of pump limiters and channeling of plasma towards neutralizer plates in the ergodic divertor. The plugging length for the pump limiter throat is computed and numerical evidence of plasma flux channeling between the conductor bars of the ergodic divertor is presented. The effect of the Tore Supra ergodic divertor on edge plasma state and edge plasma transport is discussed. (orig.)

Energy efficient ammonia heat pump. Final report

Energy Technology Data Exchange (ETDEWEB)

Madsen, Claus; Pijnenburg, B.; Schumann Grindorf, H. [Danish Technological Institute, Aarhus (Denmark); Christensen, Rolf [Alfa Laval, Lund (Sweden); Rasmussen, Bjarne D. [Grundfos, Bjerringbro (Denmark); Gram, S.; Fredborg Jakobsen, D. [Svedan Industri Koeleanlaeg, Greve (Denmark)

2013-09-15

The report describes the development of a highly effective ammonia heat pump. Heat pumps play an increasingly important role in the search for more effective use of energy in our society. Highly efficient heat pumps can contribute to reduced energy consumption and improved economy of the systems which they are a part of. An ammonia heat pump with high pressure reciprocating compressor and a novel split condenser was developed to prove potential for efficiency optimization. The split of the condenser in two parts can be utilized to obtain smaller temperature approaches and, thereby, improved heat pump efficiency at an equal heat exchanger area, when compared to the traditional solution with separate condenser and de-superheater. The split condenser design can also be exploited for heating a significant share of the total heating capacity to a temperature far above the condensing temperature. Furthermore, the prototype heat pump was equipped with a plate type evaporator combined with a U-turn separator with a minimum liquid height and a liquid pump with the purpose of creating optimum liquid circulation ratio for the highest possible heat transfer coefficients at the lowest possible pressure drop. The test results successfully confirmed the highest possible efficiency; a COP of 4.3 was obtained when heating water from 40 deg. C to 80 deg. C while operating with evaporating/condensing temperatures of +20 deg C/+73 deg C. (Author)

Hybrid System Modeling and Full Cycle Operation Analysis of a Two-Stroke Free-Piston Linear Generator

Directory of Open Access Journals (Sweden)

Peng Sun

2017-02-01

Full Text Available Free-piston linear generators (FPLGs have attractive application prospects for hybrid electric vehicles (HEVs owing to their high-efficiency, low-emissions and multi-fuel flexibility. In order to achieve long-term stable operation, the hybrid system design and full-cycle operation strategy are essential factors that should be considered. A 25 kW FPLG consisting of an internal combustion engine (ICE, a linear electric machine (LEM and a gas spring (GS is designed. To improve the power density and generating efficiency, the LEM is assembled with two modular flat-type double-sided PM LEM units, which sandwich a common moving-magnet plate supported by a middle keel beam and bilateral slide guide rails to enhance the stiffness of the moving plate. For the convenience of operation processes analysis, the coupling hybrid system is modeled mathematically and a full cycle simulation model is established. Top-level systemic control strategies including the starting, stable operating, fault recovering and stopping strategies are analyzed and discussed. The analysis results validate that the system can run stably and robustly with the proposed full cycle operation strategy. The effective electric output power can reach 26.36 kW with an overall system efficiency of 36.32%.

Plugging regime in the pump limiter throat

International Nuclear Information System (INIS)

Ghendrih, P.; Grosman, A.; Samain, A.; Capes, H.; Morera, J.P.

1988-08-01

The plugging regime -with no outstreaming neutral flux- is studied for a closed configuration pump limiter (throat). We derive the plugging length and the neutral density build-up at the neutralizer plate. The analytical expressions are supported by numerical evidence. We find an improved efficiency related to the throat effect mainly due to neutral-sidewall interactions

Investigation of piston ring – cylinder liner dry wear using a block-on-ring test rig

DEFF Research Database (Denmark)

Bihlet, Uffe; Klit, Peder; Felter, Christian L.

Characterization of the wear of piston rings and cylinder liner is an important aspect of large two stroke diesel engine design. Two major wear mechanisms exist; corrosive wear and mechanical wear. This paper deals with the most aggressive form of the latter, which is known as scuffing. Different...... that ceramic coating on the piston ring decreases the dry wear rate of both piston ring and liner, while the coefficient of friction is increased....

A thermoeconomic model of a photovoltaic heat pump

International Nuclear Information System (INIS)

Mastrullo, R.; Renno, C.

2010-01-01

In this paper the model of a heat pump whose evaporator operates as a photovoltaic collector, is studied. The energy balance equations have been used for some heat pump components, and for each layer of the photovoltaic evaporator: covering glaze, photovoltaic modules, thermal absorber plate, refrigerant tube and insulator. The model has been solved by means of a program using proper simplifications. The system input is represented by the solar radiation intensity and the environment temperature, that influence the output electric power of the photovoltaic modules and the evaporation power. The model results have been obtained referring to the photovoltaic evaporator and the plant operating as heat pump, in terms of the photovoltaic evaporator layers temperatures, the refrigerant fluid properties values in the cycle fundamental points, the thermal and mechanical powers, the efficiencies that characterize the plant performances from the energy, exergy and economic point of view. This study allows to realize a thermoeconomic comparison between a photovoltaic heat pump and a traditional heat pump under the same working conditions.

Hydrodynamics of piston-driven laminar pulsating flow: Part 2. Fully developed flow

International Nuclear Information System (INIS)

Aygun, Cemalettin; Aydin, Orhan

2014-01-01

Highlights: • The piston-driven laminar pulsating flow in a pipe is studied. • Fully developed flow is examined analytically, numerically and experimentally. • An increase in F results an increase in the amplitude of the centerline velocity. • The characters of the radial velocity profiles critically depend on both the frequency and the phase angle. • The near/off-wall flow reversals are observed for F = 105, 226 and 402. - Abstract: Piston-driven pulsating flow is a specific type of pressure-driven pulsating flows. In this study, piston-driven laminar pulsating flow in a pipe is studied. This study mainly exists of two parts: developing flow and fully developed flow. In this part, hydrodynamically fully developed flow is examined analytically, numerically and experimentally. A constant value of the time-averaged Reynolds number is considered, Re = 1000. In the theoretical studies, both analytical and numerical, an inlet velocity profile representing the experimental case, i.e., the piston driven flow, is assumed. In the experiments, in the hydrodynamically fully developed region, radial velocity distribution and pressure drop are obtained using hot-wire anemometer and pressure transmitter, respectively. The effect pulsation frequency on the friction coefficient as well as velocity profiles are obtained. A good agreement is observed among analytical, numerical and experimental results

Method of estimating time scales of atmospheric piston and its application at Dome C (Antarctica)

International Nuclear Information System (INIS)

Kellerer, A.; Sarazin, M.; Butterley, T.; Wilson, R.

2007-01-01

Temporal fluctuations of the atmospheric piston are critical for interferometers as they determine their sensitivity. We characterize an instrumental setup,termed the piston scope, that aims at measuring the atmospheric time constant, τ0, through the image motion in the focal plane of a Fizeau interferometer.High-resolution piston scope measurements have been obtained at the observatory of Paranal, Chile in April 2006. The derived atmospheric parameters are shown to be consistent with data from the astronomical site monitor, provided that the atmospheric turbulence is displaced along a single direction.The piston scope measurements of lower temporal and spatial resolution were recorded for what is believed to be the first time in February 2005 at the Antarctic site of Dome C. Their reanalysis in terms of the new data calibration sharpens the conclusions of a first qualitative examination [Appl. Opt. 45, 5709 (2006)

Test results for the Oasis 3C high performance water-pumping windmill

Energy Technology Data Exchange (ETDEWEB)

Eggleston, D.M. [DME Engineering, Midland, TX (United States)

1997-12-31

The WINDTech International, L.L.C. Oasis 3C, a 3 m diameter, high-performance water-pumping windmill, was tested at the DME Engineering Wind Test Site just south of Midland, Texas from August through December, 1996. This machine utilizes a 3:1 gearbox with rotating counterweights, similar to a conventional oilfield pumping unit, driven by a multibladed rotor. The rotating counterweight system balances most of the pumping loads and reduces gear loads and starting torque by a factor of at least two and often by a factor of four or more. The torque reduction substantially extends gear and bearing life, and reduces wind speeds required for starting by 30 to 50% or more. The O3C was tested pumping from a quiescent fluid depth of 12.2 m (40 ft) from a 28.3 m (93 ft)-deep well, with additional pumping depth simulated using a pressure regulator valve system. A 9.53 cm (3.75 in.) diameter Harbison-Fischer seal-less single-acting piston pump was used to eliminate pump seal friction as a variable, and standard O3C stroke lengths of 30.5 and 15.2 cm (12 and 6 inches) were used. The regulator spring was set to give a maximum stroke rate of 33 strokes per minute. The water pumped was returned to the well after flowing through a settling tank. The tests were performed in accordance with AWEA WECS testing standards. Instrumentation provided 16 channels of data to accurately measure machine performance, including starting wind speeds, flow rates, O3C azimuth, tail furl angle, wind direction tracking errors, RPM, sucker rod loads, and other variables. The most significant performance data is summarized herein. A mathematical model of machine performance was developed that fairly accurately predicts performance for each of three test conditions. The results verify that the O3C is capable of pumping water at wind speeds from 30% to more than 50% lower than comparable un-counterbalanced units.

Modular Porous Plate Sublimator /MPPS/ requires only water supply for coolant

Science.gov (United States)

Rathbun, R. J.

1966-01-01

Modular porous plate sublimators, provided for each location where heat must be dissipated, conserve the battery power of a space vehicle by eliminating the coolant pump. The sublimator requires only a water supply for coolant.

Localization of the pumping reflector for a Nd:YAG laser

Energy Technology Data Exchange (ETDEWEB)

Kim, Kwang Suk; Kim, Chul Joong [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1994-12-01

For the first year plan of this program, the pumping reflectors, which are gold plated reflectors and ceramic diffuse reflectors, of the Nd:YAG laser have been localized. The laser output performances with these reflectors have been investigated. Developed reflectors can be applied successfully to our commercialized Nd:YAG laser which was worked in previous project. We designed the optical pumping system with GaAlAs diode laser bar to improve the pumping efficiency. Moreover, we investigated a simple pumping technique without changing the fleshlamp, which makes the Nd:YAG laser operate in a cw, a pulsed, and a mixed of the two mode. We expert many new applications of this diversification of output pulse shapes in industry and in medicine. 38 figs, 9 tabs, 18 refs. (Author).

Development of an optical time-resolved measurement system under high-pressure and low-temperature with a piston-cylinder pressure cell

Science.gov (United States)

Tsuchiya, Satoshi; Kino, Yohei; Nakagawa, Koichi; Nakagawa, Daisuke; Yamada, Jun-ichi; Toda, Yasunori

2016-04-01

To perform the femtosecond pump-probe spectroscopy under high pressure and low temperature, we constructed a measurement system with a piston cylinder type pressure cell installing an optical fiber bundle. The applied pressure was achieved to 6 kbar and the cell was cooled down to 15 K. Several demonstrations revealed that broadening and change of polarization of pulse (duration of ˜120 fs) owing to the dispersions in the fiber bundle are much small indicating that those have little influence on the measurement of carrier relaxation dynamics. In the measurements of κ-(BEDT-TTF)2Cu(NCS)2 under 1.3 kbar at 43 K, we have successfully detected the polarization anisotropy of the carrier relaxation dynamics and estimated the decay time in the same way as the normal measurement.

Free-piston engine linear generator for hybrid vehicles modeling study

Science.gov (United States)

Callahan, T. J.; Ingram, S. K.

1995-05-01

Development of a free piston engine linear generator was investigated for use as an auxiliary power unit for a hybrid electric vehicle. The main focus of the program was to develop an efficient linear generator concept to convert the piston motion directly into electrical power. Computer modeling techniques were used to evaluate five different designs for linear generators. These designs included permanent magnet generators, reluctance generators, linear DC generators, and two and three-coil induction generators. The efficiency of the linear generator was highly dependent on the design concept. The two-coil induction generator was determined to be the best design, with an efficiency of approximately 90 percent.

Assembly for electrical conductivity measurements in the piston cylinder device

Science.gov (United States)

Watson, Heather Christine [Dublin, CA; Roberts, Jeffrey James [Livermore, CA

2012-06-05

An assembly apparatus for measurement of electrical conductivity or other properties of a sample in a piston cylinder device wherein pressure and heat are applied to the sample by the piston cylinder device. The assembly apparatus includes a body, a first electrode in the body, the first electrode operatively connected to the sample, a first electrical conductor connected to the first electrode, a washer constructed of a hard conducting material, the washer surrounding the first electrical conductor in the body, a second electrode in the body, the second electrode operatively connected to the sample, and a second electrical conductor connected to the second electrode.

Analysis of multicriteria models application for selection of an optimal artificial lift method in oil production

Directory of Open Access Journals (Sweden)

Crnogorac Miroslav P.

2016-01-01

Full Text Available In the world today for the exploitation of oil reservoirs by artificial lift methods are applied different types of deep pumps (piston, centrifugal, screw, hydraulic, water jet pumps and gas lift (continuous, intermittent and plunger. Maximum values of oil production achieved by these exploitation methods are significantly different. In order to select the optimal exploitation method of oil well, the multicriteria analysis models are used. In this paper is presented an analysis of the multicriteria model's application known as VIKOR, TOPSIS, ELECTRE, AHP and PROMETHEE for selection of optimal exploitation method for typical oil well at Serbian exploration area. Ranking results of applicability of the deep piston pumps, hydraulic pumps, screw pumps, gas lift method and electric submersible centrifugal pumps, indicated that in the all above multicriteria models except in PROMETHEE, the optimal method of exploitation are deep piston pumps and gas lift.

Compact heat and mass exchangers of the plate fin type in thermal sorption systems: Application in an absorption heat pump with the working pair CH3OH-LiBr/ZnBr2

Science.gov (United States)

Becker, Harry

The possible application of Compact Heat and Mass Exchangers (CHME) in a gas fired Absorption Heat Pump (AHP) for domestic heating is studied. The above mentioned heat and mass exchangers are of the plate type. The space between the parallel and plain plates is filled up with corrugated plates of a certain height. The plain and finned plates are stacked and welded together. This gives a heat and mass exchanger which is very compact, expressed by a high area density (m2/m3). This leads to heat and mass transfer processes with small temperature and concentration differences. For testing purposes a pilot plant was built using the above type of components in order to test their heat and/or mass transfer performance. Only the generator is of the Shell And Tube (SAT) type. As the working pair, CH3OH - LiBr/ ZnBr2 was chosen, with the alcohol as the solvent and the salt mixture as the absorbent. This leads to sub atmospheric working pressures with only solvent in the vapor phase. Three series of experiments have been carried out, during which the input parameters were varied over a certain range. It is concluded that the plate fin CHMES are very suitable for application in an AHP for domestic heating purposes.

Free-piston linear generator and the development of a solid lubrication system

OpenAIRE

Virsik, Roman; Rinderknecht, Frank; Friedrich, Horst E.

2017-01-01

The free piston linear generator is a new electromechanical generator. It converts chemical energy into electrical energy by means of a combustion process, a linear generator and a gas spring. The free piston linear generator doesn´t use any crankshaft, which is responsible for a lot of losses. Thereby the technology aims to have better properties than other electromechanical generators: higher efficiency over wide range of operating points, better noise-vibration-harshness, package … This pu...

The development and testing of ceramic components in piston engines. Final report

Energy Technology Data Exchange (ETDEWEB)

McEntire, B.J. [Norton Co., Northboro, MA (United States). Advanced Ceramics Div.; Willis, R.W.; Southam, R.E. [TRW, Inc., Cleveland, OH (United States)

1994-10-01

Within the past 10--15 years, ceramic hardware has been fabricated and tested in a number of piston engine applications including valves, piston pins, roller followers, tappet shims, and other wear components. It has been shown that, with proper design and installation, ceramics improve performance, fuel economy, and wear and corrosion resistance. These results have been obtained using rig and road tests on both stock and race engines. Selected summaries of these tests are presented in this review paper.

Experimentally Studied Thermal Piston-head State of the Internal-Combustion Engine with a Thermal Layer Formed by Micro-Arc Oxidation Method

Directory of Open Access Journals (Sweden)

N. Yu. Dudareva

2015-01-01

Full Text Available The paper presents results of experimental study to show the efficiency of reducing thermal tension of internal combustion engine (ICE pistons through forming a thermal barrier coating on the piston-head. During the engine operation the piston is under the most thermal stress. High temperatures in the combustion chamber may lead to the piston-head burnout and destruction and engine failure.Micro-arc oxidation (MAO method was selected as the technology to create a thermal barrier coating. MAO technology allows us to form the ceramic coating with a thickness of 400μm on the surface of aluminum alloy, which have high heat resistance, and have good adhesion to the substrate even under thermal cycling stresses.Deliverables of MAO method used to protect pistons described in the scientific literature are insufficient, as they are either calculated or experimentally obtained at the special plants (units, which do not reproduce piston operation in a real engine. This work aims to fill this gap. The aim of the work is an experimental study of the thermal protective ability of MAO-layer formed on the piston-head with simulation of thermal processes of the real engine.The tests were performed on a specially designed and manufactured stand free of motor, which reproduces operation conditions maximum close to those of the real engine. The piston is heated by a fire source - gas burner with isobutene balloon, cooling is carried out by the water circulation system through the water-cooling jacket.Tests have been conducted to compare the thermal state of the regular engine piston without thermal protection and the piston with a heat layer formed on the piston-head by MAO method. The study findings show that the thermal protective MAO-layer with thickness of 100μm allows us to reduce thermal tension of piston on average by 8,5 %. Thus at high temperatures there is the most pronounced effect that is important for the uprated engines.The obtained findings can

A Piston-Rotaxane with Two Potential Stripes: Force Transitions and Yield Stresses

Directory of Open Access Journals (Sweden)

Edith M. Sevick

2013-10-01

Full Text Available We examine a rod piston-rotaxane system, where the positions of several mobile rings on the axle are controlled by an external force acting on one of the rings. This allows us to access the translational entropy of the rings. For a simple rotaxane molecule with an axle that has uniform ring-axle interactions along its length, the molecule behaves like a miniature piston filled with a one-dimensional ideal gas. We then examine the effect of two stripes on the axle, having different ring-axle interactions with the mobile rings, so that one section is of high energy (repulsive for the rings and another section is of lower energy (or attractive. This kind of rotaxane can exhibit rapid changes in displacement or force, and in particular, this molecule can exhibit a yield stress in which the piston suddenly compresses under a small increase in the applied force.

Free-piston Stirling technology for space power

International Nuclear Information System (INIS)

Slaby, J.G.

1994-01-01

An overview is presented of the NASA Lewis Research Center free-piston Stirling engine activities directed toward space power. This work is being carried out under NASA's new Civil Space Technology Initiative (CSTI). The overall goal of CSTI's High Capacity Power element is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA space missions. The Stirling cycle offers an attractive power conversion concept for space power needs. Discussed in this paper is the completion of the Space Power Demonstrator Engine (SPDE) testing - culminating in the generation of 25 kW of engine power from a dynamically-balanced opposed-piston Stirling engine at a temperature ratio of 2.0. Engine efficiency was approximately 22 percent. The SPDE recently has been divided into two separate single-cylinder engines, called Space Power Research Engines (SPRE), that now serve as test beds for the evaluation of key technology disciplines. These disciplines include hydrodynamic gas bearings, high-efficiency linear alternators, space qualified heat pipe heat exchangers, oscillating flow code validation, and engine loss understanding. The success of the SPDE at 650 K has resulted in a more ambitious Stirling endeavor - the design, fabrication, test and evaluation of a designed-for-space 25 kW per cylinder Stirling Space Engine (SSE). The SSE will operate at a hot metal temperature of 1050 K using superalloy materials. This design is a low temperature confirmation of the 1300 K design. It is the 1300 K free-piston Stirling power conversion system that is the ultimate goal; to be used in conjunction with the SP-100 reactor. The approach to this goal is in three temperature steps. However, this paper concentrates on the first two phases of this program - the 650 K SPDE and the 1050 K SSE

Design aspects of commercial open-loop heat pump systems

Energy Technology Data Exchange (ETDEWEB)

Rafferty, Kevin

2000-01-01

Open loop (or groundwater heat pump systems are the oldest of the ground-source systems. Common design variations include direct (groundwater used directly in the heat pump units), indirect (building loop isolated with a plate heat exchanger), and standing column (water produced and returned to the same well). Direct systems are typically limited to the smallest applications. Standing column systems are employed in hard rock geology sites where it is not possible to produce sufficient water for a conventional system. Due to its greater potential application, this paper reviews key design aspects of the indirect approach. The general design procedure is reviewed, identification of optimum groundwater flow, heat exchanger selection guidelines, well pump control, disposal options, well spacing, piping connections and related issues.

Design Aspects of Commerical Open-Loop Heat Pump Systems

Energy Technology Data Exchange (ETDEWEB)

Rafferty, Kevin

2001-03-01

Open loop (or groundwater heat pump systems are the oldest of the ground-source systems. Common design variations include direct (groundwater used directly in the heat pump units), indirect (building loop isolated with a plate heat exchanger), and standing column (water produced and returned to the same well). Direct systems are typically limited to the smallest applications. Standing column systems are employed in hard rock geology sites where it is not possible to produce sufficient water for a conventional system. Due to its greater potential application, this paper reviews key design aspects of the indirect approach. The general design procedure is reviewed, identification of optimum groundwater flow, heat exchanger selection guidelines, well pump control, disposal options, well spacing, piping connections and related issues.

Investigation of Different Piston Ring Curvatures on Lubricant Transport along Cylinder Liner in Large Two-Stroke Marine Diesel Engines

DEFF Research Database (Denmark)

Overgaard, Hannibal Christian; Klit, Peder; Vølund, Anders

2016-01-01

A theoretical investigation of the hydrodynamic lubrication of the top compression piston ring in a large two-stroke marine diesel engine is presented. The groove mounted piston ring is driven by the reciprocal motion of the piston. The ring shape follows a circular geometry and the effect...

Investigation of different piston ring curvatures on lubricant transport along cylinder liner in large two-stroke marine diesel engines

DEFF Research Database (Denmark)

Overgaard, H; Klit, P; Vølund, A

2017-01-01

A theoretical investigation of the hydrodynamic lubrication of the top compression piston ring in a large two-stroke marine diesel engine is presented. The groove mounted piston ring is driven by the reciprocal motion of the piston. The ring shape follows a circular geometry and the effect...

Palm Power Free-Piston Stirling Engine Control Electronics

Science.gov (United States)

Keiter, Douglas E.; Holliday, Ezekiel

2007-01-01

A prototype 35We, JP-8 fueled, soldier-wearable power system for the DARPA Palm Power program has been developed and tested by Sunpower. A hermetically-sealed 42We Sunpower Free-Piston Stirling Engine (FPSE) with integral linear alternator is the prime mover for this system. To maximize system efficiency over a broad range of output power, a non-dissipative, highly efficient electronic control system which modulates engine output power by varying piston stroke and converts the AC output voltage of the FPSE into 28Vdc for the Palm Power end user, has been designed and demonstrated as an integral component of the Palm Power system. This paper reviews the current status and progress made in developing the control electronics for the Palm Power system, in addition to describing the operation and demonstrated performance of the engine controller in the context of the current JP-8 fueled Palm Power system.

Spherical-wave expansions of piston-radiator fields.

Science.gov (United States)

Wittmann, R C; Yaghjian, A D

1991-09-01

Simple spherical-wave expansions of the continuous-wave fields of a circular piston radiator in a rigid baffle are derived. These expansions are valid throughout the illuminated half-space and are useful for efficient numerical computation in the near-field region. Multipole coefficients are given by closed-form expressions which can be evaluated recursively.

Application of ceramic short fiber reinforced Al alloy matrix composite on piston for internal combustion engines

Directory of Open Access Journals (Sweden)

Wu Shenqing

2010-11-01

Full Text Available The preparation and properties of ceramic short fiber reinforced Al-Si alloy matrix composite and it’s application on the piston for internal combustion engines are presented. Alumina or aluminosilicate fibers reinforced Al-Si alloy matrix composite has more excellent synthetical properties at elevated temperature than the matrix alloys. A partially reinforced Al-Si alloy matrix composite piston produced by squeeze casting technique has a firm interface between reinforced and unreinforced areas, low reject rate and good technical tolerance. As a new kind of piston material, it has been used for mass production of about 400,000 pieces of automobile engines piston. China has become one of a few countries in which aluminum alloy matrix composite materials have been used in automobile industry and attained industrialization.

Free-piston Stirling technology for space power

Science.gov (United States)

Slaby, Jack G.

1989-01-01

An overview is presented of the NASA Lewis Research Center free-piston Stirling engine activities directed toward space power. This work is being carried out under NASA's new Civil Space Technology Initiative (CSTI). The overall goal of CSTI's High Capacity Power element is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA space missions. The Stirling cycle offers an attractive power conversion concept for space power needs. Discussed here is the completion of the Space Power Demonstrator Engine (SPDE) testing-culminating in the generation of 25 kW of engine power from a dynamically-balanced opposed-piston Stirling engine at a temperature ratio of 2.0. Engine efficiency was approximately 22 percent. The SPDE recently has been divided into two separate single-cylinder engines, called Space Power Research Engine (SPRE), that now serve as test beds for the evaluation of key technology disciplines. These disciplines include hydrodynamic gas bearings, high-efficiency linear alternators, space qualified heat pipe heat exchangers, oscillating flow code validation, and engine loss understanding.

Analysis on and Optimization of a Circular Piezoelectric Composite Laminate for a Micro-Pump Driver

International Nuclear Information System (INIS)

Jia, Jianyuan; Wang, Weidong; Huang, Xinbo

2002-01-01

Among the various micro-pump actuation devices, piezoelectric composite laminate actuation has become an effective method. Due to lacking of analysis treatments, the design of this type micro-pump is in a great limitation. In this paper, an electromechanical-coupled mechanics model is established for the circle-flake micro-actuator. A kind of analysis and design method is presented that piezoelectric plate's radial strain induced by inverse piezoelectric effect is equivalently substituted with transverse stress on piezoelectric composite laminates. It is pointed out that the equivalent transverse load depends on the edge electric field distribution of parallel plate capacitor. The question has been solved that where the neutral plane in the piezoelectric composite laminates lies. Finally, an optimization design is developed on the radius ratio of piezoelectric-to-silicon plate radius by utilizing of FEA modeling

Multi-dimensional scavenging analysis of a free-piston linear alternator based on numerical simulation

Energy Technology Data Exchange (ETDEWEB)

Mao, Jinlong; Zuo, Zhengxing; Li, Wen; Feng, Huihua [School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081 (China)

2011-04-15

A free-piston linear alternator (FPLA) is being developed by the Beijing Institute of Technology to improve the thermal efficiency relative to conventional crank-driven engines. A two-stroke scavenging process recharges the engine and is crucial to realizing the continuous operation of a free-piston engine. In order to study the FPLA scavenging process, the scavenging system was configured using computational fluid dynamics. As the piston dynamics of the FPLA are different to conventional crank-driven two-stroke engines, a time-based numerical simulation program was built using Matlab to define the piston's motion profiles. A wide range of design and operating options were investigated including effective stroke length, valve overlapping distance, operating frequency and charging pressure to find out their effects on the scavenging performance. The results indicate that a combination of high effective stroke length to bore ratio and long valve overlapping distance with a low supercharging pressure has the potential to achieve high scavenging and trapping efficiencies with low short-circuiting losses. (author)

Plate heat exchanger - inertia flywheel performance in loss of flow transient

International Nuclear Information System (INIS)

Abou-El-Maaty, Talal; Abd-El-Hady, Amr