High-pressure Pump Research Articles

Reduction of Energy Consumption of Brackish Water Reverse Osmosis Desalination System Via Model Based Optimisation

Reverse Osmosis (RO) process is being engaged to yield fresh water from brackish water sources. However, the RO process is characterized by its high specific energy consumption (SEC) owing to high-pressure pumps. The current study focuses on reducing the SEC of the brackish water RO desalination plant using model-based optimization practice. The inlet conditions of RO process such as the feed pressure, flow rate (individual membrane module and total plant) and temperature, have a substantial influence on the performance indicators namely, water productivity, product concentration and SEC. Therefore, the optimisation of this study has been directed to determine optimal inlet conditions within feasible limits to minimise SEC. Arab Potash Company (APC) brackish water RO desalination plant has been considered as the case study. The optimal inlet conditions have resulted in a significant energy saving of 27.97% depending on the set of decision variables being considered at a fixed brackish water feed concentration.

Theoretical and Experimental Flow Characteristics of a Large-Scale Annular Channel in Terms of Deformation Gradient, Eccentricity, and Water Compressibility

Hydraulic water plunger pumps have come to be widely used in coal mining, seawater desalination, and oil exploitation due to their high output pressure and large flow characteristics. In a high-pressure large-flow plunger pump, the leakage of the annular channel of the plunger pair is an essential factor affecting volume efficiency. The axial pressure gradient exists in the fluid inside the annular channel, resulting in the plunger and plunger sleeve forming similar funnel-like shapes. Moreover, the characteristics of large diameter, high working pressure, and low fluid viscosity of the plunger pump will lead to the complicated flow of the annular channel. The influence of eccentricity and structural deformation on leakage is difficult to evaluate. Therefore, considering the deformation gradient and eccentricity of the plunger pair and the compressibility of the water, the deformation equations and leakage equations of the annular channel under the laminar and turbulent flow state are derived in this study. The eccentricity and leakage of the annular channel under different pressure conditions are measured using a built sealing test bench. It is proved that the discrepancy between the calculated model and the experimental results is less than 6% under different pressures, which effectively predicts the sealing performance of plunger pumps. The results show that under the laminar flow condition, the effects of eccentricity, structural deformation, and medium compressibility on leakage are 148%, 4.92%, and 0.92%, respectively. In turbulent conditions, they were 31%, 2.84%, and 1.19%, respectively. Besides, the reasonable material pairing of the plunger friction pair can reduce the variation of leakage due to structural deformation.

Study on the balance force regulation method of multi-stage pump balance drum system

Balanced drum systems are widely used in high-pressure multi-stage pump axial force balancing mechanisms. When the pump working, the fluid (solid-fluid mixture) collides with each other or rubs against the pump case, and the balance drum is affected by this situation for a long time, so wear of the balance drum gap occurs from time to time. The first is to study how the axial force of the multistage pump changes at different balance drum gap sizes in this paper. Based on the energy equation and momentum equation, and on the basis of maintaining the original balance force unchanged, a new equation of resistance pressure difference relationship is established. The corresponding relationship between balance drum gap and balance pipe orifice plate is obtained by solving this equation. The result shows that the larger the balance drum gap, the greater the balance drum balance force decreases obviously, and the multistage pump residual axial force increases in multiples. The adjustment formula of balance force can be used to obtain the radial size of the balance pipe orifice plate under different balance drum gap, when the gap increases, to keep the balance force constant, the diameter of the orifice plate should be increased gradually. After adjusting the balance force, the fluid velocity uniformity and velocity average angle of balance pipe increases, the flow pattern in the pipe becomes uniform, the gap leakage increases and the pump efficiency decreases. The pump hydraulic properties and balancing the axial force have an opposing relationship, that is, by promoting the drum balance force, the pump hydraulic properties will be reduced. Due to processing balance drum is complex, frequent replacement is time-consuming and costly, so this article provides a handy approach for enhancing the balance force of balance drum, the results of the study can provide guarantees for the balance drum system optimization and long period stable operation of the multistage pump.

Energy Efficiency Optimization in Onboard SWRO Desalination Plants Based on a Genetic Neuro-Fuzzy System

This work presents a novel intelligent control system based on a Genetic Neuro-Fuzzy tool to optimize and improve the performance of a seawater reverse osmosis desalination plant (SWRO) on board a marine vessel. This investigation pays special attention to minimizing energy consumption to improve the energy efficiency of this marine installation. The system analyzes measurements of different variables—seawater pH, seawater conductivity, permeate flow rate, permeate conductivity, and total energy consumed—in order to provide the most appropriate value of permeate flow rate control and operating pressure of the high-pressure pump (HPP). This intelligent method allows the plant to achieve output values nearer to the desired setpoints set by the plant operators.

Study on Cavitation of Port Plate of Seawater Desalination Pump with Energy Recovery Function

To address the problem of low integration and efficiency of reverse osmosis desalination system, an energy-recovery type incurve multiple acting pump is developed with integrated functions of a high-pressure pump, energy recovery device and booster pump. In order to determine its flow range and suppress cavitation generation, a mathematical model of the port plate is established, combining the realizable k-ɛ turbulence model and the Schnerr-Sauer cavitation model to obtain the internal flow field characteristics of the port plate. The effects of different rotational speeds and inlet pressures on cavitation were analyzed to obtain the gas volume fraction distribution rules. The design is based on the pressure and mass flow monitoring test device to verify the numerical calculation results. The results show that the experimental and simulation data match accurately, and with the increase in speed and the decrease in inlet pressure, the cavitation phenomenon becomes serious and the flow coefficient is reduced. The optimal working speed of the pump in this paper is 520 r/min and the output flow is 200 L/min. Compared with conventional products, the volume is reduced by more than 40%.

Assessment of influence of the Common Rail system high-pressure fuel pump design on regularity of fuel supply to a fuel accumulator

BACKGROUND: At the present time all worldwide diesel engine manufacturers have directed their development strategies on the way of reduction of harmful emissions, fuel efficiency improving and increasing of the power per liter. Using only accumulator type system is not sufficient for the goals achievement. It is necessary to use new auxiliary units, such as an exhaust catalyst, an exhaust recirculation system, injection of additional liquids together with diesel fuel, as well as to improve the existing units. Increasing the accuracy of injection rate of a nozzle will make it possible to adjust the engine fuel system more precisely, that will have a positive effect on all development directions of diesel engine engineering. Injection rate of a nozzle is dependent on fuel pressure in the nozzle inlet and on control signal timing. Pressure pulsation with stable timing cause irregularity of injection rate of a nozzle. Possibility of decreasing of nozzle inlet pressure pulsation is mainly defined by design of a high-pressure fuel pump, as it supplies fuel partially. The design optimization will make it possible to increase the accuracy of injection rate, that will make a positive effect on development of the diesel engines promising areas.
 AIMS: Study of irregularity of fuel supply by fuel pumps of various diesel engines designs with the Common Rail fuel accumulation system, aimed to decrease fuel oscillations and to improve stability of injection rate of a nozzle.
 METHODS: In order to assess the efficiency of high-pressure fuel pump designs, these designs were simulated in the specialised software. Theoretical studies of fuel supply irregularity for various designs of the pumps were carried out.
 RESULTS: Graphs of non-uniformity of fuel supply of high-pressure pumps depending on their design are obtained.
 CONCLUSIONS: Based on simulations, the conclusions about design influence on fuel supply irregularity of various designs of pump are made, recommendations for use are given.

A novel technology for optimizing dissolved air flotation unit efficiency via secondary saturation of the flotation cell with air bubbles and thin-layer settling

Specific ways to improve the technology for flotation (DAF) wastewater treatment have been determined. Prospects to increase functioning of DAF units via using thin-layer cells, and improving the hydraulic size of the emerging flotation aggregates have been shown. The latter is feasible due to secondary saturation of the flotation cell with air bubbles of 0.1–0.3 mm diameter floating in laminar flow regime and creating light turbulence thereof. The possibility of obtaining an air-water mixture with air bubbles during their breaking up in the annular space of the saturator-separator is experimentally proven. It is feasible to separate the air bubbles from the major fluid flow in the centrifugal field due to rotational and translational motion of the separated mixture. It is established that converting the Q-H vane pump characteristics, which provides for pumped flow circulation and useful flow selection for the two medium-pressure ejectors operating in series, allows to: ensure stable air ejection from the atmosphere; significantly increase the vane pump head H via reducing the supplied useful flow; exclude a compressor and replace an expensive high-pressure pump with a lower operating pressure one.

Copper leaching effects on combustion characteristics and particulate emissions of a direct injection high pressure common rail diesel engine

In this work the impact of a helicoidally shaped copper duct on combustion characteristics and particulate emissions of a 2.2 L Direct Injection High Pressure Common Rail (DI HPCR) diesel engine were investigated. The copper duct is at the core of an electrical device constituted by magnetic coils powered at 12.5 V. This device is installed on the fuel line immediately before the high-pressure pump. Three operating conditions, low to medium loads, at 1500 and 2000 rpm have been considered. Combustion characteristics were analysed by post-processing in-cylinder pressure measurements, while an AVL Smoke Meter was used to monitor particulate emissions. The diesel fuel had initially a copper content less than 0.02 ppm; fuel was sampled at regular intervals during engine operation and inductively coupled plasma mass spectrometry (ICP-MS) analysis showed a monotonic increase of its copper content, up to 0.19 ppm (mg/kg). A soot reduction up to 28% was measured when the device was connected to the fuel line, compared to the baseline. No change in the combustion delay over time suggests that soot abatement was primarily due to a copper-mediated oxidizing effect. A preliminary analysis performed on heat release data acquired under the same engine operating conditions suggests an increase in the average value and standard deviation of the heat release peaks when the device is powered on. Additionally, four operating conditions were also investigated but the copper was replaced by a Teflon duct; the results indicates that if no metal is leached into the fuel, the magnetic field does not have any major effect on combustion and emission characteristics of the diesel engine.

Research on Structurally Constrained KELM Fault-Diagnosis Model Based on Frequency-Domain Fuzzy Entropy

As the core equipment of the high-pressure diaphragm pump, the working conditions of the check valve are complicated, and the vibration signal generated during operation displays non-stationary and nonlinear characteristics. In order to accurately describe the non-linear dynamics of the check valve, the smoothing prior analysis (SPA) method is used to decompose the vibration signal of the check valve, obtain the tendency term and fluctuation term components, and calculate the frequency-domain fuzzy entropy (FFE) of the component signals. Using FFE to characterize the operating state of the check valve, the paper proposes a kernel extreme-learning machine (KELM) function norm regularization method, which is used to construct a structurally constrained kernel extreme-learning machine (SC-KELM) fault-diagnosis model. Experiments demonstrate that the frequency-domain fuzzy entropy can accurately characterize the operation state of check valve, and the improvement of the generalization of the SC-KELM check valve fault model improves the recognition accuracy of the check-valve fault-diagnosis model, with an accuracy rate of 96.67%.

Effect of high pump pressure on chloride migration in ITZ of concrete

Concrete pumping tests with distances of 150, 300, 450, 600, and 750 m were conducted to study the influence of pumping on the compressive strength and the chloride migration of concrete. Long-distance pumping had a significant impact on the chloride migration coefficient of concrete, and it was observed that the Cl− migration coefficient of concrete decreased with an increase in the pumping distance. When the pumping distance was 750 m, the Cl− diffusion coefficient of C40 and C60 concrete decreased by 28.73 and 27.65%, respectively. The Backscatter (BSE) test was conducted, and the porosity and thickness of ITZ were determined following the threshold segmentation method. The porosity and thickness of ITZ decreased with an increase in the pumping distance. When pumped over a distance of 750 m for C40 and C60 concrete, the porosity of ITZ decreased by 59.78 and 58.57%, respectively, and the thickness of ITZ decreased by 26.43 and 25.96%, respectively. The effect of pumping on the porosity of ITZ was greater than that on the thickness of ITZ. Considering ITZ effect, dilution effect and tortuosity effect, the influence of pumping on chloride migration coefficient of concrete was analyzed and calculated quantitatively.

The low power diesel-generator unit with electronically controlled fuel injection

BACKGROUND: Diesel engines, used in generator units, primarily operate in variable loading conditions. Therefore, their technical and economic performance generally deteriorate when the load decreases. It arises from the diesel engine fuel system feature, where pressure and quantity of the fuel, injected into a cylinder, reduces with the load decreasing. As a result, the injection becomes sluggish, the quality of mixing process and combustion becomes worse.
 AIMS: Improvement of effective indicators of the diesel-generator units with electronically controlled fuel injection.
 METHODS: Adjustment of operation modes of the diesel engine of the electrical power unit carried out with use of electronically controlled Denso solenoid, connected to the high-pressure fuel pump via an adapter.
 RESULTS: Results of the motor testing of the low power diesel-generator unit with electronically controlled fuel feed system are described in the article. The oscillograph charts of valve displacement and solenoid magnet winding current, presented in the article, confirm its operation efficiency. Sharp decrease in boost current at the stage of valve lift can be explained by onset of back EMF. Stable solenoid operation at diesel operation velocity of 30003100 min-1 is achieved by means of boost impulse supply to its winding. The boost impulse is supplied from a voltage upconverter and generated by discharge of preliminary charged booster capacitor.
 CONCLUSIONS: Separated fuel feed adjustment in each high-pressure pump section made possible to reduce intersectional fuel feed irregularity to zero. Significant fuel consumption reduction was revealed with the motor testing of the low power diesel-generator unit with electronically controlled fuel feed system (the reduction reaches 10% on low loading operation modes). As mentioned by authors, transition to electronic control of operation modes of diesel engines of autonomous electrical power units does not require major engine design change only to dismantle a mechanical controller and to set an adapter with electronically controlled bypass valve at a section of the high-pressure fuel pump. Electronic control unit supplies current to the valve. For autonomous electrical power units, transition to this control method can be done in typical repair workshop conditions, and an update of one unit (e.g. the KIPOR KDE19AE3) costs 13 950 rubles. By doing so, one electrical power unit may save up to 1191 liters of fuel and more than 63.96 thousands rubles at a cost of 53.7 rubles per liter.

Energy, Exergy and Simulation Analysis of Steam Driven High Pressure Pumps of Cogeneration Plants

Energy, Exergy and Simulation Analysis of Steam Driven High Pressure Pumps of Cogeneration Plants

A new test method for simulating wear failure of hydraulic pump slipper pair under high-speed and high-pressure conditions

In practical engineering, it is very difficult to obtain data on the slipper wear of hydraulic pumps, especially under high-speed, high-pressure conditions, which limits the development of fault diagnosis technology for hydraulic pumps. At present, a test method that can accurately simulate the operating state of the slipper pair under high-speed and high-pressure conditions does not exist. The reliable load-bearing design of the slipper pair is difficult to carry out effectivetest verification, which limits the development of high-speed and high-pressure piston pumps. Therefore, an experimental design method was proposed to directly simulate the high-speed, high-pressure friction state of the slipper pair based on the change law of reprinting residual pressing force.

Effect of solid particles in oil on tribological characteristics of the valve plate friction pair of a high-pressure vane pump

The friction pair wear in a high-pressure vane pump caused by solid particles in oil is a significant factor that affects the pump's service life. The study investigates the effects of solid particles on the tribological characteristics of the valve plate friction pair of a high-pressure vane pump. The effects of varying solid particle diameters (5–20 μm) and concentrations (0.001–0.015%) on the friction coefficient, wear rate, and surface morphology of the valve plate friction pair in a high-pressure vane pump were investigated. In addition, to study the effect of diameter and concentration of solid particle on the vane pump's volumetric efficiency, the volumetric efficiency of the vane pump was tested. According to the results, when the solid particle concentration was 0.001%, the friction coefficient increased first and then decreased as the solid particle diameter increased, with no obvious running-in process. Furthermore, the wear rate increased first and then decreased as the solid particle diameter also increased. When the solid particle diameter was greater than 15 μm, the friction coefficient decreased as the concentration increased, and a distinct running-in process was unobserved. During this time, the relationship between the valve plate's wear rate and the solid particle concentration was approximately linear. The wear of the valve plate with solid particles included the impact of scraping wear as well as the abrasive wear and slight adhesive wear caused by solid particles. The vane pump's volumetric efficiency decreased as the solid particle diameter increased with a linear relationship. The volumetric efficiency of the pump also showed a downtrend when the solid particle concentration increased. This research provides a reference for valve plate design and improving the performance of high-pressure vane pumps.

Experimental and Numerical Investigation on High-Pressure Centrifugal Pumps: Ultimate Pressure Formulation, Fatigue Life Assessment and Topological Optimization of Discharge Section

Experimental and Numerical Investigation on High-Pressure Centrifugal Pumps: Ultimate Pressure Formulation, Fatigue Life Assessment and Topological Optimization of Discharge Section

Macroscopic and Microscopic Spray Characteristics of Dimethyl Ether in a Constant Volume Spray Chamber Using a Mechanical Fuel Injection System for Automotive Applications

Abstract Spray investigations are critical for understanding internal combustion engine combustion. Optimised spray atomisation helps improve engine output/performance and reduce tailpipe emissions. The spray from the injector nozzle depends on nozzle hole diameter, fuel injection pressure, ambient density, pressure and temperature in the spray chamber, and test fuel properties. This study evaluated macroscopic and microscopic spray characteristics of dimethyl ether (DME) and baseline diesel under atmospheric conditions (1.013 bar pressure at 298 K temperature). It correlated the spray parameters with distinctive physicochemical properties of diesel and DME using dimensionless numbers, namely Reynolds number, Weber number, and Ohnesorge number. The fuel injection system consisted of a high-pressure mechanical injection pump and mechanical fuel injectors having an original equipment manufacturer fixed nozzle opening pressure in the constant volume spray chamber. The microscopic spray investigations were performed using a phase Doppler interferometer along the spray direction at three axial distances (50, 70, and 90 mm) from the nozzle. The three orthogonal spray droplet velocities of diesel and DME were compared. The droplet number-size distributions for baseline diesel and DME were compared. Macroscopic spray characteristics were evaluated using high-speed imaging. Reynolds number was higher for DME, leading to more turbulence in the spray and accelerating the spray breakup phenomenon. Weber number of DME was also much higher than baseline diesel due to its lower surface tension. The higher Weber and lower Ohnesorge numbers justified the finer droplets of DME sprays. DME showed superior spray atomization characteristics than baseline diesel, leading to superior fuel–air mixing and efficient and sootless combustion.

A proposed safe design of the reverse osmosis system

In a seawater reverse osmosis (SWRO) desalination plant, the SWRO system includes the high-pressure pump, the high-pressure piping, the energy recovery equipment, the pressure vessels and the RO membranes. The membranes are the most delicate part of the plant and are subject to continuous operational variations during water production. Designers of plants propose various solutions to protect the RO system through the use of mechanical and control/automation devices. This paper aims to present several design and operational considerations and address them through a proposed technical solution. With the correct combination of instruments, the RO membranes are protected and the overpressure in the system can only happen due to malfunction or failure of the instruments.

Elevation-distributed multistage reverse osmosis desalination with seawater pumped storage

A seawater reverse osmosis (RO) plant layout based on multistage RO with stages located at different elevations above sea level is described. The plant uses the weight of a seawater column from pumped storage as head pressure for RO (gravity-driven multistage RO) or to supplement high-pressure pumps used in RO (gravity-assisted multistage RO). The use of gravitational force reduces the specific energy for RO compared to using high-pressure pumps. By locating the RO stages at different elevations based on demand sites, the total specific energy consumption for RO and permeate transport to different elevations above sea level is reduced from that for locating the RO process entirely at sea level followed by lifting the desalinated water. A final RO stage at sea level uses seawater pressurized by energy recovery from the residual energy of the brine generated from the preceding RO stage. Examples of the plant layout that do not include pump inefficiency and head losses in pipes are described for South Sinai, Egypt, which is a mountainous region that suffers from water scarcity. A gravity-driven multistage RO with a storage tank at 660 m above sea level is considered. For five RO stages located 316–57 m above sea level with 10% recovery at each stage, the specific energy is ~ 32% lower than that for a plant located at sea level operating at the minimum specific energy followed by lifting the same quantity of desalinated water to the elevations of the distributed RO stages. For two stages located at 222 and 57 m above sea level with 30 and 20% recovery, respectively, the reduction in specific energy is ~ 27%. For gravity-assisted five-stage RO with the first stage at 260 m above sea level, while the last stage is at sea level with 10% recovery at each stage the reduction in specific energy is ~ 32%. The proposed RO plant layouts can be adapted to other regions with comparable topography.

Analysis of Influencing Factors in Pilot Experiment for Synthesis of Natural Gas Hydrate by Spray Method

In recent years, the technology of storing and transporting natural gas in the form of hydrate has received a lot of attention. At present, the research on the synthesis of natural gas hydrate for the purpose of storage and transportation is still in the laboratory stage, and its synthesis process is in the design and conception stage. The influencing factors of natural gas hydrate synthesis under pilot-scale conditions are more complex. Moreover, pilot experiments are oriented to actual production, and its economic feasibility and operational convenience have higher requirements. This paper aimed to study the influencing factors of gas hydrate synthesis by spray method under pilot-scale conditions. Under specific conditions of surfactant and pressure, we carried out research on the effects of reaction temperature, different forms of atomizers, high-pressure pump flow, experimental water, and other factors. Experiments show that the optimal synthesis conditions were a temperature of −5 °C, a pressure of 5 MPa, a conical nozzle, a generated gas hydrate as the hydrate of type I structure, and a gas storage capacity of 1:123 (gas–water ratio).

Study on Friction Characteristics of Slipper Pair of Large Displacement High-Pressure Piston Pump

The reference value of the oil film thickness and friction coefficient of the slipper pair is critical to the development of the piston pump, especially for 750 mL/r displacement piston pumps. To explore the computing method and range of the reference value mentioned applicable to 750 mL/r displacement piston pumps, this study aims to propose the modified calculation model of the oil film thickness based on the real clearance flowrate and obtain the value range of the friction coefficient of the slipper pair. Through the friction test of the slipper pair, the mean deviation ratio of the oil film thickness between the modified value, theoretical value, and the measured value was calculated and compared, respectively. The variation law of the friction under the influence of different speeds and working pressures was analyzed. Finally, the range of the equivalent friction coefficient with the upper and lower limit surfaces was obtained. The results show that the mean deviation ratio between the modified oil film thickness value and the measured value is mainly within 6%, while that of the theoretical method is mainly from 6% to 8%, and the mean of the difference between the two deviation ratios is about 3%, verifying the feasibility of the modified model used for the calculation of the reference value. Meanwhile, the value of the equivalent friction coefficient fluctuates in the range of 0.006–0.018, which is affected more significantly by the working pressure than the speed, suggesting that the working pressure can be given priority as the design basis of the friction coefficient for 750 mL/r displacement piston pumps.