Conventional Mechanical Pump Research Articles

Mechanisms of energy conversion in induction magnetohydrodynamic pumps for transporting conducting liquids

Efficiency of energy conversion in magnetohydrodynamic (MHD) pumps is relatively lower compared with conventional mechanical pumps. The processes of energy conversion in an induction MHD pump are identified and the energy efficiencies of the processes are evaluated based on the numerical simulations. Two numerical models with different geometrical dimensions are built to simulate all involved processes. The results illustrate that vortices suddenly occur in the pump channel when the flow rate reduces below a critical value. The size and scale of the vortices are dependent on the modeling dimension. By analyzing the energy conversion among different forms of energy, it is demonstrated that the energy conversion is strongly correlated with the vortex flow. The appearing vortices at low flow rates result in both large Ohmic dissipation and negative power of Lorentz force, which are the main obstructions for energy transfer from the input power to the fluid pressure energy. In addition, the overall efficiency of this machine is estimated using the model containing external components (e.g., coils, stators and ducts). It is found that the energy dissipation in the external components plays an increasing role of reducing the energy efficiency with the increasing flow rate.

Development of a Single-Suction Double-Discharge Automatic Transmission Oil Pump for Power-Consumption Reduction

The high power consumption of the automatic transmission oil pump has led to the undertaking of efficiency improvement studies over a number of decades. For the unique idea of the present paper, a single automatic transmission oil pump was adopted to satisfy the requirements of both the high- and low-pressure lines. A single-suction double-discharge oil pump, which has two separate discharge ports that are connected to the individual pressure lines, was developed for the elimination of any unnecessary power consumption. The flow distribution ratio was analyzed according to the chamber volume ratio of the primary and secondary discharge sections. A single-suction double-discharge pump was designed using a flow analysis for which, design parameters such as the rotor diameter change and the eccentricity were utilized. A backpressure hole that is adjacent to the secondary discharge section drastically alleviated the internal pressure and the hydraulic torque in the pumping chambers. The power reduction effect of the oil pump prototype was compared with that of a conventional mechanical pump, and an experimental evaluation was conducted according to the operating conditions. The power reduction rate was estimated to be 16.5 %.

Demonstration of thermochemical oxygen pumping for atmosphere control in reduction reactions

Solar thermochemical cycles as a means to produce fuels such as hydrogen, carbon monoxide, or syngas using a metal oxide as oxygen carrier offer a promising route to the efficient conversion and storage of solar energy. Even though the theoretical potential of such cycles can be very attractive, many challenges for reaching high process efficiencies remain unsolved. One challenging aspect is the parasitic energy cost for maintaining low partial pressures of oxygen during the reduction step. As previously proposed by the authors, thermochemical oxygen pumps have the theoretical potential to maintain low partial pressures of oxygen at considerably lower energy costs than conventional mechanical pumps. The work presented here demonstrates the proof of concept of thermochemical oxygen pumping. The reduction extents of a metal oxide after temperature swing experiments are analyzed for test runs with and without thermochemical oxygen pumping, clearly showing higher reduction extents for the former cases. The effects of different operational parameters on the reduction of the metal oxide are investigated and options for reduction extent enhancement are depicted.

Cantilever Piezoelectric Micro-Pump Modeling Based on Bond Graph Port

Micro-pump is a fundamental component of micro-fluid machine, which has obtained an extensive use in medical care, bio-engineering, and the other fields. Its application will continuously be expanded. Its structure is different from the conventional mechanical pump as its size and flow limit, thus it is difficult to directly apply traditional method to micro-pump modeling. Firstly, the paper introduces the structure of the cantilever piezoelectric micro-pump, in which its input/output can be seen as two separate one-way valves, and its structure can be simplified for a simple beam model. Secondly, presents a port model based on bond graph port analysis, and selects the basic components in order to understand the micro-fluid characteristics of the micro-pump. Finally, gives the result of simulation to obtain the process of the volume change of micro-pump companying with the input pressure and the displacement of deformable film..

Power Electronics Cooling of 100 W/cm$^{2}$ Using AC Electroosmotic Pump

The power electronics cooling system should be able to dissipate very high heat flux densities (watts per surface area). For that, many solutions can be used: liquid forced convection, heat pipes, capillary loops, and so on. In the forced convection cooling system case, one of the hotspots is the mechanical pump. We propose in this paper to study the possibility of replacing the conventional mechanical pumps by electroosmotic (EO) pump. The pump based on porous ceramic seems well suited for this application. In this paper, after a few reminders on electroosmosis pumping theory, the new modification of our second prototype will be presented. Then, the test bench and the experiment results of the second prototype with a power electronics device will be presented and discussed. It will be shown that the pump generates 20 ml/min and it is used to evacuate 100 W/cm2 of heat flux generated by the power electronics device.

A novel thermally driven pump and its test in a supercritical CO2loop system

SUMMARY In this paper, a novel thermally driven pump is introduced, and its test in a closed supercritical CO2 loop cycle system is studied. The thermally driven pump is a refrigerant-circulating pump composed of two expansion tanks, which has less electricity consumption and better reliability compared with conventional mechanical pumps. Experimental results showed that the system efficiency of the present thermally driven pump in the supercritical CO2 loop can be enhanced compared with that using the mechanical feed pump. In addition, it was found that the system efficiency with the thermally driven pump decreases with the outlet temperature of condenser. The thermal energy utilization efficiency of the loop system with the thermally driven pump can be increased when the condenser has higher efficiency. Copyright © 2012 John Wiley & Sons, Ltd.

Performance study of supercritical CO2-based solar Rankine cycle system with a novel-concept thermally driven pump

In this article, a supercritical CO2-based solar Rankine cycle system (SRCS) with a novel-concept thermally driven pump is studied. The thermally driven pump is a refrigerant-circulating pump composed of two expansion tanks and having merits of low power consumption and high reliability in comparison with conventional mechanical pump. The application of the present thermally driven pump in the supercritical CO2-based SRCS shows that an oscillatory flow is realized in the system and the system thermal efficiency is enhanced compared to the SRCS using the mechanical feed pump.

Dielectric properties of mica‐alumina combined insulation at high temperatures

AbstractDevelopment of sodium‐immersed‐type Electromagnetic Pumps (EMP) is expected to improve reliability, safety, maintainability, and construction cost of the Fast Breeder Reactor (FBR) compared with the conventional mechanical pumps. To realize the EMP, establishment of a high‐temperature‐resistant electrical insulating system is indispensable.A mica‐alumina combination is selected for the insulating system at temperatures higher than 500°C. Using this insulating system, an aging pretest was performed. The aging condition was to apply 1.5‐kV ac voltage in the nitrogen atmosphere at 550°C for 4000 hours. The dielectric properties before and after the aging were measured to understand the tendency of temporal change in the aging.In this result, the dielectric performance after aging was improved compared with the initial performance. The curious phenomenon was clarified to be caused by a decrease of organic component in the insulation, which remained due to incomplete burning. Also, the possibility of thermal runaway was considered to be higher as a dielectric breakdown mechanism.

マイカ•アルミナ複合絶縁材の高温絶縁特性

Development of sodium-immersed-type Electromagnetic Pumps (EMP) is expected to improve reliability, safety, maintainability, and construction cost of the Fast Breeder Reactor (FBR) compared with the conventional mechanical pumps. To realize the EMP, establishment of a high-temperature-resistant electrical insulating system is indispensable. A mica-alumina combination is selected for the insulating system at temperatures higher than 500°C. Using this insulating system, an aging pretest was performed. The aging condition was to apply 1.5-kV ac voltage in the nitrogen atmosphere at 550°C for 4000 hours. The dielectric properties before and after the aging were measured to understand the tendency of temporal change in the aging. In this result, the dielectric performance after aging was improved compared with the initial performance. The curious phenomenon was clarified to be caused by a decrease of organic component in the insulation, which remained due to incomplete burning. Also, the possibility of thermal runaway was considered to be higher as a dielectric breakdown mechanism.

A novel cryogenic molecular beam. Application to supersonic jet spectroscopy of gases

A novel method for molecular supersonic free-jet spectroscopy, which uses acryopump rather than mechanical pumps to maintain a low background pressure, is described. Advantages of this method include its low cost, relative ease of installation in many types of spectrometer and the potential for efficient recovery of valuable samples. The technique has been demonstrated with a compact liquid-nitrogen cryopump installed in the sample compartment of an FTIR spectrometer. Jet-cooled infrared rovibrational spectra of CO 2, NO 2 and N 2O 4 indicate a similar degree of rotational and vibrational cooling as that obtained using conventional mechanical pumps.

High-Vacuum System for Teaching and Research

A simple, compact, and inexpensive high-vacuum system is described. It consists of a detachable vacuum chamber connected through a specially machined aluminum block to a conventional mechanical pump. The block contains all of the vacuum valves and ducts required for initial evacuation of the system, its maintenance at low pressures, and admission of sample gases. Residual vapors are pumped by zeolite-coated copper surfaces, which are housed in a detachable container connected to the block. The vacuum chamber can be pumped from atmospheric pressure down to pressures suitable for electron-beam experiments in approximately 90 sec. Ultimate pressures of 2 × 10−5 Torr can be achieved without cooling the zeolite. Pressures below 4 × 10−6 Torr are possible if the zeolite is cooled by liquid nitrogen. Applications of the system in lecture demonstrations, undergraduate projects, and graduate-level research are discussed.