Pump Mode Research Articles

Modelling a pumped storage power plant on the example of the Porąbka Żar power plant

This article presents the idea and mathematical model of a pumped storage power plant. PSPS Porąbka Żar was selected as the real object for modelling. Due to the specificity of the operation of an intervention-regulatory and scheduled nature related to the coverage of power demand in the power system, the possibility of different modes of operation was taken into account in the model. Porąbka-Żar power plant is a pearl of hydro-engineering on the global stage. It is the first underground and the second largest pumped storage power plant in Poland. It is located in Międzybrodzie Bialskie, in the Silesian province. The short distance between the upper reservoir of the power station, located on Mt. Żar, and the lower reservoir of the międzybrodzkie lake, the high average head of the power station of 432 m above sea level, create great opportunities for accessibility and interference in the operation of the power station. It is equipped with four reversible Francis turbine sets, which operate simultaneously with a total capacity of 500 MW in the generator mode and 542 MW in the pumping mode. Due to its high potential and short turn-on and turn-off times of the turbine sets, it plays an important role in the national power system. The mathematical model was made in Matlab - Simulink software. An important role in the control process of the facility is played by the forecast of both power demand and contingencies. The forecasting model is equipped with elements of artificial intelligence. In addition, the article shows the possibility of supplementing an operating power plant with hybrid elements. The analysis is supported by commentary and a number of charts

Technologies and means of protection in process of managing pumping stations

This paper aims to analyze automatic protection and control measures at pump stations in the event of constant accumulation of groundwater and water dripping from the pump, leading to flooding in the pump station engine room. To prevent this, the pumping station's machine room should monitor the level of groundwater and water leaks from the pump and, promptly, automatically remove excess water with a pump. The excess water is collected in special reservoirs. From these, the ERSU series sensor, which is based on a contact electrode controller, does not allow it to constantly monitor the level in the storage tank within the required limits; therefore, as a completely automated system, it is unstable and cannot support the regulatory requirements for preventing it from starting one of its technical operations. The article discusses the positive aspects of technical solutions and experimental work in the DRV5023 IC with MSP430G2131 controller and no more than 2.7 mA consumer, NE555 IC-based timer and pump mode, stable contactless sensor, sensor-based automatic monitoring, and pumping system. The results are given. (12-17 seconds.) Preparation to start the pumping process is also a standard 4.7 V. power supply circuit. The work is based on production experience and is innovative.

Hydrodynamic optimization of pump-turbine runner

The paper suggests the approach to automatic CFD-based optimization of the pump-turbine runner. An in-house 3D flow solver CADRUN is used for the solution of steady-state RANS equations and evaluation of objective functions in representative operating points of turbine and pump operating regimes. Both efficiency and cavitation characteristics are taken into account. Two approaches have been considered, resulting in 4- and 3-objective shape optimization problems. These problems were solved using multi-objective genetic algorithm. It was shown that the obtained optimized runners feature increased efficiency both in turbine and pump mode with cavitation performance, similar to that of the initial runner.

Модульно-параметричний принцип розробки проектів шестеренних гідравлічних машин

The conventional system of design development of gear-type hydraulic machines and their implementation is not sufficiently perfect for a number of reasons. This system cannot be effective in the conditions of large-scale production. The purpose of the work is to create such a principle of designing a model range of gear hydraulic machines, which optimizes the conditions of production and marketing, with the subsequent reduction of the cost of production. To achieve the goal, the theory of "redundant connections" was used, and the design scheme of the hydraulic machine was analyzed. On the results of the conducted analysis, several possible schemes for the extraction of "redundant connections" were developed, and the calculation was carried out. From the proposed schemes, the most appropriate scheme for creating a gear-type hydraulic machine was determined - a scheme using the central load of the driving gear and a barrel-shaped profile of the longitudinal contour of the tooth of the driven gear. The paper also considers additional benefits arising from the removal of redundant connections. On the basis of the developed diagram of the action of forces in gear engagement, it is shown how deviations from the geometric accuracy of the gear affect the operation of the hydraulic machine and why the proposed scheme with a barrel-shaped profile of the longitudinal contour of the tooth is more appropriate. Among the important results of the research should be attributed the synthesized perspective scheme of design of a gear hydraulic machine. The use of the proposed scheme will allow the reduction of redundant connections (from 7 to 5, relative to the conventional scheme), which will contribute to the reduction of additional deformations and energy losses when working in the hydraulic motor mode and fluid losses when working in the hydraulic pump mode. And the implementation of one of the coupled gears with a barrel-shaped longitudinal profile of the teeth will ensure the stabilization of the displacement moment when the unit is operating in the hydraulic motor mode and will stabilize the hydraulic efficiency parameter when operating in the pump mode.

Study of operating mode of axial and centrifugal pumps with hydroabrasive wear of parts in flow section of pumping units

To date, a significant amount of work has been done to study the processes of cavitation and hydroabrasive wear in laboratory conditions. Using existing equations for assessing hydroabrasive or cavitation wear leads to certain inaccuracies since the action mechanism underlying them does not correspond to the actual operating conditions of hydraulic machines. Very little has been studied about the issues associated with joint and intense cavitation-abrasive wear, which always occur in fullscale hydraulic machines operating on natural watercourses with high turbidity. So far, the wear of the working bodies of centrifugal and axial pumps has been poorly studied, depending on the mode of their operation, and a methodology has not been developed for selecting operating modes, taking into account the wear of their parts. In this paper, the wear of parts of axial and centrifugal pumps in laboratory conditions is studied, and the dependences of wear on the characteristic dimensions and duration of their operation are given. The results of micrometering of the working parts of the pumps showed that the blades of the impellers along the length and width wear out unevenly both in size and shape. In axial and centrifugal pumps, the most intense wear occurs at the outlet sections of the impeller blades and their sealing elements. When pumping muddy water for 2000 hours, the sealing gaps of type D pumps with a head of 75–80 m are 2.8– 3.1 mm. With an increase in the end clearance of the impeller of an axial pump from the impact of a slotted cavitation-abrasive flow, the pressure value and the local concentration of solid particles in the flow play a leading role.

MODELLING THE EFFICIENCY OF THE HEAT PUMP SYSTEM WITH TANK ACCUMULATOR FOR PERMANENT AND INTERMITTENT HEATING MODES OF THE PUBLIC BUILDINGS

The paper considers mathematical modeling the efficiency of the combined heat pump systems with thermal energy storage for intermittent heating of the public buildings. The abilities of the combined heat pump system working with traditional heating system with the account of climate data values when the position of the bivalent point on the temperature axis affects at the amount of heat energy supplied from the reserved generator of heat are analyzed. Numerical modeling of processes in the combined intermittent heating system was carried out. The proposed methodology of the analysis may serve as a rational approach to further development the heat pump technologies of intermittent heating. Evaluation of the effectiveness of work modes the intermittent heating system from the operating modes of heat consumers are carried out. The proposed methodology contributes to energy efficiency of the heat pump systems with tank accumulators with the ac-count of operating modes of heat consumers. Simulation results include coefficient of performance and heating capacity. The periods of operation when the values of the coefficient of performance were very high were revealed. Analysis of the results of numerical modeling shows that for heat pump systems with heat accumulators, the load curve of heat generators is equalized, which leads to uniform operation of the heat source. The design of technical details of the heat pump was optimized with the energy balance which is well suited for the analysis of work modes of the heat pump integrated with thermal energy storage. The rational length of intermittent heating periods when the heat pump operates with heat accumulator, duration of successive heating mode and stand-by mode with charging the heat accumulator which have positive influence on energy efficiency are considered, consequently. According to the results, additional novel-ty aspect allows to optimize the technical details and work modes of the combined heat pump system at renewable sources shares to have continuous improvement of its energy efficiency. The mathematical model validated with experimental results can be employed for investigation the feasibility of integrating the tank accumulator into heat pump heating systems using renewable sources of energy.

Enhanced affinity law for centrifugal pumps at variable speed

The paper presents a novel approach for analytical representation of specific energy E and torque T curves versus discharge Q and speed N, for centrifugal pumps operated at variable speed both in pump and turbine mode. An enhanced polynomial expression valid for both E(Q,N ) and T(Q,N) is introduced and validated against experimental data.

Monitoring of rolling bearing failures as result of acceleration

The article discusses modern methods of diagnosing and technical diagnostics of irrigation pumping units to ensure reliability during operation. Using new designs of pumping power equipment and developing new operating modes provide for improving the mode of pumps based on improved diagnostics, significantly saving operating costs. Together with this provides detection, control, and prediction of multi-stage failure of the rolling bearing by monitoring the vibration trends of the centrifugal pump unit during operation.

Improving the performance of the vapor compression cycle using an internal heat exchanger

The main additional consumer of electrical energy in an electric bus is the climate system, which can consume up to 30% of electrical energy. This problem is especially relevant in Russia at low ambient temperatures. The optimal solution is to switch the vapor compression unit to heat pump mode. However, at low temperatures, its efficiency decreases and performance is insufficient. One way to improve efficiency is to use an internal heat exchanger. In this paper, we studied the effect of an internal heat exchanger on the performance of a vapor compression cycle using R290, R410a and R507a refrigerants. The influence of geometry on the performance of the internal heat exchanger is determined. The use of an internal heat exchanger makes it possible to increase coefficient of performance by 10-13%.

Numerical simulation of performance of traveling wave pump-turbine at different wave speeds in pumping mode

Fish swim by flexing their bodies and energy is transferred from the fish to the water. And the plate which imitates traveling wave motion of fish can absorb the energy of fluid under certain motion parameters. By arranging the traveling wave plate in a vertical rectangular flow channel, the flow mode is changed from external flow mode to internal flow mode. This internal flow device is called traveling wave pump-turbine, and it can operate in both pumping mode and turbine mode. The traveling wave plate is simplified into a two-dimensional plate, and the model of the traveling wave pump-turbine is established. The numerical simulation method is used to study its performance characteristics at different wave speeds when it is in pumping mode. The results show that: although it operates in pumping mode by changing the volume of the working chamber, it can output stable mass flow rate. With the increase of wave speed, the volumetric efficiency increases gradually, the time-averaged efficiency first increases and then decreases, and the maximum time-averaged efficiency can reach 0.9. The instantaneous pressure and power are relatively stable when the wave speed is low, while they fluctuate more sharply with the increase of wave speed.

Development and validation of an AI-Driven model for the La Rance tidal barrage: A generalisable case study

In this work, an AI-Driven (autonomous) model representation of the La Rance tidal barrage was developed using novel parametrisation and Deep Reinforcement Learning (DRL) techniques. Our model results were validated with experimental measurements, yielding the first Tidal Range Structure (TRS) model validated against a constructed tidal barrage and made available to academics. In order to proper model La Rance, parametrisation methodologies were developed for simulating (i) turbines (in pumping and power generation modes), (ii) transition ramp functions (for opening and closing hydraulic structures) and (iii) equivalent lagoon wetted area. Furthermore, an updated DRL method was implemented for optimising the operation of the hydraulic structures that compose La Rance. The achieved objective of this work was to verify the capabilities of an AI-Driven TRS model to appropriately predict (i) turbine power and (ii) lagoon water level variations. In addition, the observed operational strategy and yearly energy output of our AI-Driven model appeared to be comparable with those reported for the La Rance tidal barrage. The outcomes of this work (developed methodologies and DRL implementations) are generalisable and can be applied to other TRS projects. Furthermore, this work provided insights which allow for more realistic simulation of TRS operation, enabled through our AI-Driven model.

Experimental study of a centrifugal pump operating as a hydraulic turbine

An experimental investigation of centrifugal pump has been carried out to study its characteristics in pump and turbine mode operation (PAT). The correlation between pump and PAT performance is a major problem. Several methods have been developed to predict the best efficiency of pumps running as turbines, but their results are not in good coincidence with experimental data for all pumps. Fluid dynamic behavior of PAT changes appreciably, in relation to its localized and distributed hydraulic losses, velocity profiles and pressures at homologous points. It is not possible to infer the behavior of a PAT using similarity parameters from pump mode performance; very large errors are made. This paper presents the experimental parameters of the operating of a PAT with specific number low. In order to determine the pump’s characteristic as turbine, we used a closed-circuit experimental setup in which the admission pressure head was realized with another pump and the correlation between the diameter of the PAT and the specific number for three different ranges of flow was determined. This is based on an experimental database on a centrifugal pump of specific number 17 .80 [RPM, m3 /s, m] in bothrotation modes and for a speed range of rotation between 250 and 2500 RPM. All required parameters were measured to achieve complete characteristic curves of the reverse pump. The functional characterization showed curves of the hydraulic machine in the turbine mode with variation of operating parameters, such as rotation speeds, heights, and flow rates. With the results obtained, the comparatives made allowed observing the influence of these variations on the performance of the PATs. Curves obtained allowed inferring the behavior in turbine mode from pump mode parameters. Values obtained from the derived correlations showed good match with experimental results.

Hydraulic loss analysis in a pump-turbine with special emphasis on local rigid vortex and shear

Since the pump as turbine is increasingly employed in energy storage, improving efficiency in both pump and turbine modes is required for economic benefits. This study aims to analyze vortex flow characteristics and vortex control methods in both modes to reduce hydraulic loss. In this paper, a delayed detached eddy simulation was applied in a low specific speed pump-turbine. Based on the entropy production analysis and vorticity binary decomposition in the local vortices, the results show that the local shear is the leading cause of hydraulic loss instead of the existence of vortices. The average wake loss can be 1.6 times higher than the loss in jet regions in pump mode, but there is little difference in the distribution of shear and vortices in the wake flow in turbine mode. The local loss caused by the rotor–stator interaction with a tongue effect at blade passing frequency is up to threefold over the loss without a tongue effect in both modes. Reducing shear and ratio of shear to rigid vorticity of the local vortices via modification in the volute tongue angle to suppress the tongue effect can be an effective way to decrease hydraulic loss in both modes.

Mathematical model of a cavity pump installation for separate-alternate operation of reservoirs

A mathematical model is developed for the separate-alternate operation of two layers by a screw pumping unit equipped with an electrovalve for switching between development objects. The model is based on the equation for the balance of fluid volumes flowing from the formation into the well, pumped out by the pump and accumulating in the well. Changes in bottomhole pressure, fluid inflow from reservoirs, pump feed in pumping and accumulation modes for the upper and lower reservoirs are analyzed at different rotational speeds of a screw rod pump. The model can be used to estimate the duration of the cycles of the upper and lower layers in the design of separate-alternate modes of screw rod installations. Keywords: simultaneous-separate mode, separate-alternate mode, screw pump, bottomhole pressure, inflow from the reservoir, feed. dpepelyaev@tehproekt.perm.ru, karbon@tatais.ru, urazakk@mail.ru

Bypass Control strategy of a Pump as Turbine in a Water Distribution Network for energy recovery

Water Distribution Networks (WDNs) are subject to leakages due to pipes aging, resulting in water and pressure losses. These issues are solved by installing Pressure Reduction Valves (PRVs) to decrease the pressure in WDNs. Depending on the application, PRVs can waste large amount of energy, hence the substitution of PRVs with Pumps used as Turbines (PaTs) can be a good compromise in terms of economic and technical aspects to reduce leakages and recover energy. Currently the share of PaT is not yet fully developed due to the certain technical challenges yet to be addressed, as providing an affordable control strategy closer to the real working conditions in a WDN. Hence, more experimental activities are required. For these reasons, in this work an experimental campaign was carried with the aim to investigate the behavior of a PaT according to a possible layout that could be embedded into a WDN. Firstly, the machine was characterized both in pump and turbine modes. Moreover, the machine working conditions limits have been analysed in terms of runaway and blocked-rotor curves. Then, turbine tests were carried out at constant speed with a typical hydraulic control scheme by means of a PRV installed in series to the PaT and a second one installed on a bypass. As a result, this analysis highlighted the feasibility to recover a consistent amount of hydraulic energy otherwise wasted under typical WDN daily pressure and flow rate patterns, with promising results in terms of the operating point control of the machine.

Squeezed Light Generation in Three-Channel Nonlinear Coupler with Second-Harmonic Generation and Frequency Mismatch

Squeezed states of light in a three-channel nonlinear coupler with second-order nonlinearity using the phase space method and the analytical perturbative method is reported in this paper. The system is studied under the frequency mismatch condition, where the frequencies of the pump mode are not common. The effect of frequency mismatch on the generated squeezed states is investigated. We have found that the frequency mismatch does significantly affect the behavior of the generated squeezed states only at higher values of linear coupling between the waveguides. By increasing the frequency mismatch, the squeezing pattern also evolves from a collapses-revivals-like squeezing into a constant oscillation.

Piston Wear Detection and Feature Selection Based on Vibration Signals Using the Improved Spare Support Vector Machine for Axial Piston Pumps.

A piston wear fault is a major failure mode of axial piston pumps, which may decrease their volumetric efficiency and service life. Although fault detection based on machine learning theory can achieve high accuracy, the performance mainly depends on the detection model and feature selection. Feature selection in learning has recently emerged as a crucial issue. Therefore, piston wear detection and feature selection are essential and urgent. In this paper, we propose a vibration signal-based methodology using the improved spare support vector machine, which can integrate the feature selection into the piston wear detection learning process. Forty features are defined to capture the piston wear signature in the time domain, frequency domain, and time-frequency domain. The relevance and impact of sparsity in 40 features are illustrated through the single and multiple statistical feature analysis. Model performance is assessed and the sparse features are discovered. The maximum model testing and training accuracy are 97.50% and 96.60%, respectively. Spare features s10, s12, Ew(8), x7, Ee(5), and Ee(4) are selected and validated. Results show that the proposed methodology is applicable for piston wear detection and feature selection, with high model accuracy and good feature sparsity.

Modeling of a ring-core trench-assisted few-mode BDFA for seven-mode signal gain equalization.

In this paper, a ring-core trench-assisted few-mode bismuth-doped fiber amplifier (BDFA) is simulated on the basis of the three-energy level. The fiber is designed to support four modes of signal group transmission for practical considerations, including LP01, LP11, LP21, and LP31. The results suggest that (1) it is possible to obtain gain equalization of the three signal groups by using the LP21 mode pump independently, where the maximum difference in modal gain (MAX DMG) is about 0.9dB, except for the LP31 mode signal; (2) by combining the LP01 and LP31 mode pumps, the average gain of the groups increases by 14%, and the MAX DMG decreases by nearly 60% (3.8 to 1.5dB) compared to the LP01 pump alone; and (3) with the same combination of mode pumps, the ring-core BDFA (1.5dB) achieves better gain equalization than the single-core BDFA (2.8dB). The analysis is informative for the future development of a multimode BDFA.

Regulation of the mammalian-brain V-ATPase through ultraslow mode-switching.

Vacuolar-type adenosine triphosphatases (V-ATPases)1-3 are electrogenic rotary mechanoenzymes structurally related to F-type ATP synthases4,5. They hydrolyse ATP to establish electrochemical proton gradients for a plethora of cellular processes1,3. In neurons, the loading of all neurotransmitters into synaptic vesicles is energized by about one V-ATPase molecule per synaptic vesicle6,7. To shed light on this bona fide single-molecule biological process, we investigated electrogenic proton-pumping by single mammalian-brain V-ATPases in single synaptic vesicles. Here we show that V-ATPases do not pump continuously in time, as suggested by observing the rotation of bacterial homologues8 and assuming strict ATP-proton coupling. Instead, they stochastically switch between three ultralong-lived modes: proton-pumping, inactive and proton-leaky. Notably, direct observation of pumping revealed that physiologically relevant concentrations of ATP do not regulate the intrinsic pumping rate. ATP regulates V-ATPase activity through the switching probability of the proton-pumping mode. By contrast, electrochemical proton gradients regulate the pumping rate and the switching of the pumping and inactive modes. A direct consequence of mode-switching is all-or-none stochastic fluctuations in the electrochemical gradient of synaptic vesicles that would be expected to introduce stochasticity in proton-driven secondary active loading of neurotransmitters and may thus have important implications for neurotransmission. This work reveals and emphasizes the mechanistic and biological importance of ultraslow mode-switching.

Analysis of two-phase flow in cavitation condition of pump-turbine based on dynamic mode decomposition method in turbine mode

Cavitation is an inevitable and important problem in the design, manufacture and operation of pump-turbine. The research on cavitation of pump-turbine is mainly focused in the pump mode, but the cavitation characteristics of turbine mode are also very important. Traditional research methods are unable to dig a large amount of research data in cavitation flow. Therefore, the dynamic mode decomposition (DMD) method is used in this study to investigate the incipient cavitation and critical cavitation of a model pump-turbine. The results show that the DMD method can accurately extract the characteristics of the runner in pump mode under cavitation conditions. The development of cavitation makes the mode decomposition of the two-phase flow field and the reconstruction of the low order modes significantly different. DMD method is more suitable for signals with clear frequency and simple mean value and pulsation. The development of cavitation makes the reconstruction of low order modes change obviously, from the inception cavitation condition of first waveform reconstruction and then mean-value reconstruction to the critical cavitation condition of first mean-value reconstruction and then waveform reconstruction. It provides a new research idea for cavitation research of pump-turbine.