Pump Mode Research Articles

Simulation and experiment investigation of a heating and power double function system with multi-objective optimization

As conventional organic Rankine cycle (ORC) power generation and reverse Carnot cycle (RCC) heat pump systems have some limitations for a fixed heat source. This study proposed a novel RCC and ORC double function system which can work in the ORC power generation mode and RCC heat pump mode for district heating and power output, respectively. The energy model is firstly established to analyze the system thermal performance and then a test rig is built to verify the performance of the system and validate the mathematical model. The economic and environmental analysis are conducted and the multi-objective optimization (MOP) method has been conducted to solve the conflicting problem between the capital cost and payback period under the different operating conditions. Results indicate that the system has good feasibility and stability which can provide 5.96 kW power output with the thermal efficiency of 5.23 % and 60.02 kW heating capacity with the COP of 2.85. The errors of the experiment to simulation COP and the error of experiment to simulation thermal efficiency value are all less than 10%. The optimization consequences based on the TOPSIS decision-making and NSGA-II technology indicate that the MOP solution has a better performance compared with the single-objective optimization.

Hybridization of battery with pico hydel for frequency regulation of microgrids using synchronverter control

Frequency regulation of autonomous microgrids with intermittent renewables is a tedious task, which requires additional support from energy storage systems (ESS). Ideally, the system requires a faster-acting ESS to arrest the initial frequency deviation and high energy capacity ESS to restore the frequency to its nominal value. Pico hydel energy storage (PHES) is one such high energy capacity ESS developed from the agricultural pumping systems. However, PHES has a slower response and cannot switch rapidly between pumping and generation modes. Hence, this paper incorporates a battery with PHES to achieve a faster dynamic response and absorb high-frequency power dynamics. Additionally, a frequency regulation strategy with synchronverter control is proposed to mimic synchronous machines, especially to reduce the rate of change of frequency (ROCOF) and frequency nadir. Firstly, a small-signal modelling approach is proposed, and it was utilized to assess the system stability through eigenvalue analysis. Subsequently, transient simulations were carried out to gauge the performance of the synchronverter strategy with vector control for frequency regulation. As a result, the frequency nadir and ROCOF were substantially reduced with the synchronverter strategy compared to the vector control based on the simulation results.

Supermode-based second harmonic generation in a nonlinear interferometer.

We demonstrate supermode-based second harmonic generation in an integrated nonlinear interferometer made of linear and nonlinear directional couplers. We use a fully-fibered pump shaper to demonstrate second harmonic generation pumped by the symmetric or anti-symmetric fundamental spatial modes. The selection of the pumping mode and thus of a specific SHG spectral profile is achieved through the selection of the fundamental wavelength and via a robust phase setting scheme. We use two methods: either post-selecting or actively setting the pumping mode. Such modal phase matching paves the way for classical and quantum applications of coupled nonlinear photonic circuits, where multimode excitation, encoding and detection are a route for multiplexing and scaling up light-processing.

Stability and Degradation Kinetic study of Bilastine in Solution State by RP-HPLC Method

Aim: The current study dealt with the degradation behavior of Bilastine and degradation kinetics of a drug in solution state. Background: Very limited information on the effect of pH on maximum stability has been published. In order to understand the degradation kinetics of bilastine, aqueous stability studies were carried out, because such studies on bilastine have not been reported in the literature, further no methods have reported about shelf-life determination of bilastine. The study design involves selection of stability indicating RP-HPLC method for estimation of drug then evaluation of degradation kinetics, shelf-life determination and validation of proposed method. Results: The Shimadzu HPLC series 1100 was used for stress degradation analysis of bilastine in tablet dosage form. The analysis was performed using Agilent ZORBAX SB-C8 (4.6×150×5µm) column and Phosphate Buffer: Acetonitrile (pH-5.0) in the ratio of 60:40 as mobile phase; wavelength selected for analysis was 254nm with the flow rate of 1mL/min at which drug showed sharp peak. The analysis was performed on the isocratic pump mode with the injection volume of 20µl. The mobile phase is used as diluent. The proposed method was found to be linear over the range 10 to 50 µg/mL. The analysis was performed by placing standard and samples with 7 different pH buffer, oxidative and neutral hydrolytic solutions in oven at 40ºC, 60⁰C and room temperature for an interval of 30, 60, 90, 120, 150, 180 mints for standard and samples. The results indicated that the pH, temperature, ionic strength and oxidation greatly influence the stability of Bilastine and the degradation behavior of Bilastine followed pseudo-first-order kinetics. Bilastine was most stable in neutral, alkaline, lower temperature conditions and lower ionic strength. Conclusion: The proposed method was found to be specific, selective and robust and successfully applied for its assay, degradation (stress testing) of drug and degradation kinetics in solution state.
 Keywords: Degradation, Stability, Bilastine, RP-HPLC, Kinetics

Energy recovery using pumps as turbines in water supply systems: a case study

An investigation was undertaken into energy recovery from water supply systems (WSSs) using pumps that can work in reverse as turbines. Napoli Est network in Italy was selected as a case study. To find the optimal locations for the installation of reversible pumps in the network, a methodology was developed and implemented using computer programming and hydraulic simulation software. A technical feasibility analysis was conducted to create different scenarios for implementation and a suitable pump was designed using computational fluid dynamics. Pump mode and reverse mode operation were simulated numerically and the performance was improved. Financial analysis showed that energy production in WSSs using pumps as turbines is a profitable alternative to traditional turbines and a renewable solution for the world's growing energy needs.

Dynamic mode-switchable and wavelength-tunable Brillouin random fiber laser by a high-order mode pump

We experimentally investigate two schemes of Brillouin random fiber laser (RFL) by using high-order-mode (HOM) pump in a few-mode fiber (FMF). The core-mode conversion between LP01 and LP11 modes is obtained in the FMF by cascading long period fiber gratings (LPFG) working at the same wavelength region. Different transversal modes of stimulated Brillouin scattering (SBS) can be implemented based on broadband long period fiber gratings (LPFG) and acoustically induced fiber gratings (AIFG). The RFL base on two broadband LPFGs can obtain high purity LP11 mode operating in the range of 1543 nm to 1565 nm. Moreover, the output mode can be dynamically switched between LP01 mode, LP11a mode and LP11b mode by modulating frequency shift keying (FSK) signal of the AIFG. This work has potential application prospects in the fields of mode division multiplexing systems, speckle-free imaging, free-space optical communication, laser material processing.

Floor Heating of Piglets Using a Thermoelectric Heat Pump

A functional and process flow diagram of an energy-saving floor heating panel using a thermoelectric assembly operating in a heat pump mode has been developed. The technique and calculation of the main heat-and-power parameters of this installation are presented. Studies of a working prototype of a floor heating panel, which have shown the high energy efficiency of the installation being developed, have been performed. It is shown that energy saving is about 15% in comparison with the serially used equipment for local heating of young animals.

Investigating external and internal working processes of mining machines when operating on “unclarified” water in underground conditions

Introduction. The article considers the issues of mine drainage study, including the working processes of the centrifugal pumps pumping “unclarified” water in arduous underground conditions. Such problems resolution is of high practical and scientific importance. Methods of research. Scientific and practical experience in the field of mine drainage was analyzed and generalized. The centrifugal pump modes were considered and promising research tasks in this field were outlined. Thus, the continuous income of groundwater to mine workings requires the uninterrupted operation of pumps. One of the most common types of mine-drainage plants is a multistage centrifugal pump which fulfills its functions to the full if properly operated. However, “unclarified” water pumping requires a new technique for centrifugal pump optimal modes determination in such service conditions. Result and analysis. The study of hydraulic, volumetric, and mechanical efficiency dependency on pump modes, the analysis of working processes within centrifugal pumps when operating on “unclarified” water, and the procedure and calculation of TsNS (multistage centrifugal pump) head-capacity curve were presented in the paper to justify the effectiveness of the presented solutions and conclusions. Scope of results. It is recommended that the research results are introduced in all enterprises conducting underground mining operations with the mine drainage.

Vortex Pump as Turbine for Energy Recovery in Viscous Fluid Flows With Reynolds Number Effect

Abstract A vortex pump with a specific speed of 76 was studied in its turbine mode by using fluent 6.3 based on the steady, three-dimensional, incompressible, Reynolds time-averaged Navier–Stokes equations, standard k-ε turbulence model, and nonequilibrium wall function in multiple reference frame system. The performance and flow structure of six liquids with different densities and viscosities were characterized, and the hydraulic, volumetric, and mechanical losses were discomposed. The correction factors of flow rate, head, shaft-power, efficiency, and disk friction power in turbine mode were correlated with impeller Reynolds number at three operational points. The conversion factors of flow rate, head, efficiency from the pump mode to the turbine mode were expressed with Reynolds number and compared with the counterparts of centrifugal pumps in the literature. It was indicated that the vortex pump can produce power as a turbine but becomes inefficient with increasing viscosity or decreasing impeller Reynolds number, especially as the number is smaller than 104 due to increased hydraulic, volumetric, and mechanical power losses. A vortex structure with radial, axial, and meridian vortices occurs in the impeller at different flow rates and viscosities. The incidence at blade leading edge and deviation angle at the blade trailing edge depend largely on flow rate and viscosity. The impeller should be modified to improve its hydraulic performance under highly viscous fluid flow conditions. The entropy generation rate method cannot demonstrate the change in hydraulic loss with viscosity when the Reynolds number is below 104.

Two-Mode Squeezed and Entangled Light Production in Parametric Oscillations

We investigate the statistical and quadrature squeezings, as well as the entanglement properties, of a two-mode light generated by non-degenerate parametric oscillations coupled to a two-mode squeezed vacuum reservoir, by employing the solutions of the quantum Langevin equations. It is found that the two-mode light shows the two-mode squeezing and entanglement for all values of the time. Moreover, it is observed that the squeezed vacuum reservoir and the growing amplitude of the pump mode enhance the degrees of two-mode squeezing and entanglement. We have also shown that the amounts of squeezing and entanglement are significant in a region, where the mean photon number is higher, and the photon number correlation is lower.

Dynamic analysis of variable-speed pumped storage plants for mitigating effects of excess wind power generation

The integration of hydropower and variable energy sources emerges as a functional method for handling power variability. Due to the advantage of adjustable power input of the pumped storage operation, variable-speed pumped storage plants (VSPSPs) have been proposed as a potential alternative to traditional fixed-speed pumped storage plants (FSPSPs) for dealing with the variable storage demand. The performance evaluation of VSPSPs in coping with changes in loads and variations in renewable energy sources during the energy storage process is crucial to ensure adequate flexibility and reliability of the grid. In this paper, the regulation performance assessment of VSPSP in mitigating wind power variations is presented based on IEEE 14-bus test system. The goal is to draw up the regulation reliability of the VSPSP under pumping mode for balancing the dynamic characteristics of wind power. Specifically, a numerical model of VSPSPs with doubly-fed induction machines is described and developed which is then validated by the measured data in the form of a case study. Moreover, by considering ten wind scenarios having differences in frequency, gradient, guts intensity, and standard deviation; simulations of VSPSP performing power regulation in the pump mode are conducted and the dynamic regulation effects are assessed. Finally, the power regulation quality comparison is provided between the power generation and storage modes to validate the regulation reliability of the VSPSP under the pumped storage operation. The regulation time delay (RTD) ratios of VSUs to FSUs are found in the range of 4.67–9.16%, demonstrating the rapidity of VSPSPs in the power regulation.

Tm:YAG single-crystal fiber laser

In this Letter, to the best of our knowledge, we present the first thulium (Tm) single-crystal fiber (SCF) laser with free-space propagation of the laser beam only. The SCF is equipped with diffusion-bonded end caps of undoped YAG for better thermal management and enhancement of pump guiding. By utilizing mode matching and pump guiding in different SCF parts, an output power of 9.1 W is achieved at ∼2.02µm with a slope efficiency of 49.4%. This straightforward approach, which is also simple to realize and is based on combining the advantages of fiber-geometry structure and crystalline properties of Tm:YAG, is expected to be useful for 2 µm amplification stages in different time formats as well.

Использование возобновляемой энергии для локального обогрева поросят

The analysis of technologies and technical means of creating a temperature regime in the piglet location zone, where two different temperature fields must be created in the cold season: one for breeding pigs, the other for suckling piglets. The article considers the question of the use of thermoelectric modules and heat pipes as a source of thermal energy in local heating installations for suckling piglets. (Research purpose) There are proposed the functional and technological scheme of the installation for local heating of young animals with the use of thermoelectric modules and heat pipes. (Materials and methods) In the developed scheme, the thermal energy of the hot circuit of thermoelectric modules is used to heat the site on which the piglets are located. (Results and discussion) The heat of the cold circuit of the thermoelectric module assimilates the thermal energy of the removed ventilation air. For the effective operation of a thermoelectric installation for local heating of piglets, it is necessary that the cooling circuit, which absorbs thermal energy from the environment, be involved in some technological process for heat removal, for example, the heated ventilation air being removed. This leads to a significant increase in the efficiency of thermoelectric modules. At the same time, the installation will operate in the heat pump mode, since the amount of heat released in the heat exchanger of the hot circuit of the thermoelectric assembly exceeds the amount of electricity consumed from the network. (Conclusions) The article presents the sample of a thermoelectric installation was developed and its laboratory tests. The article describes the energy efficiency of the use of thermoelectric modules as energy converters in thermal technological processes.

Investigation of the flow energy dissipation law in a centrifugal impeller in pump mode

Centrifugal impeller is usually designed for water pumping. Fluid get energy from impeller but also lose energy when passing through it. To improve the efficiency and have a better operation stability, it is necessary to understand the flow energy dissipation in centrifugal impeller in pump mode. In this case, a thermodynamic analysis is conducted on a model centrifugal pump unit based on computational fluid dynamics (CFD) simulation. Typical performance curve is found with a positive-slope efficiency curve and a negative-slope head curve. With the decreasing of flow rate, both the impeller head and the flow energy dissipation (FED) will rise up. The FED is found related to the flow regime. The complex undesirable flow pattern induces high FED under off-design conditions especially at very small partial-load. Based on the visualization, FED is found with two main sources including the wall friction and the flow interaction. At over-load and design-load, the wall friction induced FED is dominant. With the decreasing of flow rate, flow interaction induced FED becomes dominant. The typical strong FED sites are found related to the striking, separation, merging and interaction of both smooth flow and vortical flow. The FED analysis will correlate the pump performance estimation and guide the design.

Effects of Pulsatile and Non-Pulsatile Perfusion On Oxygenator Fibers During Pediatric Cardiopulmonary Bypass

In cardiopulmoner operations patients can be perfused with a pulsatile or nonpulsatile pump mode. The extra energy maintained by the pulsatile perfusion may have different effects on the patient and the oxygenator fiber rather than nonpulsatile perfusion. Especially the effect of pulsatile perfusion on the fibers isn’t clearly known. The purpose of this study is to investigate the effects of pulsatile and non-pulsatile blood flows on oxygenator fibers. 18 out of 32 patients that had an pediatric open heart surgery was chosen according to their aortic clamp times. 9 of 18 patients were perfused in a pulsatile mode, other 9 patients were perfused in a nonpulsatile mode. The patient blood was collected before the open heart surgery (T1), before aortic clamp (T2), after aortic clamp (T3), after 1st intensive care hour (T4) and after the 1st intensive care day (T5) in order to compare the results of whole blood and plasma proteins. At the end of the open heart operation 10 cm of oxygenator fiber was removed from the fiber bundle and taken into the phosfate buffer saline (PBS) solution after the patient had a stabile outcome. Whole blood and micro protein measurements were applied in both first fiber solution and sonicated solution. No harmful effect of pulsatile perfusion on blood cells and proteins was observed according to patient results. More blood cell aggregation and total protein adsorption was observed in nonpulsatile mode fibers results. In this study pulsatile perfusion maintained better blood compability over nonpulsatile perfusion and the extra energy in pulsatile perfusion caused better microcirculation.

Including Substrate Losses and Noise in a Quantum Mechanical Model of a Josephson Traveling-Wave Parametric Amplifier

Substrate losses affect the performance of dispersive readout of superconducting qubits. We present a quantum mechanical model of a Josephson traveling-wave parametric amplifier, including substrate losses and the associated noise contributions. Losses and noise are introduced by coupling the system Hamiltonian to a bosonic bath, where the coupling constants can be related to the loss tangent of the transmission line substrate. Closed-form solutions for the temporal evolution of discrete mode operators in the presence of losses and noise are derived, under the assumption of a strong classical pump mode. A careful analysis of the loss-induced noise contributions can lead to the formulation of limits for the scaling of ultra-low noise qubit readout.

Flow Microbalance Simulation of Pumping and Injection Unit in In Situ Leaching Uranium Mining Area

In situ leaching (ISL) uranium mining technology is an in situ mining technology in which the chemical solution is injected into the ore-bearing strata through drilling wells, and the solution moves along the ore bed by controlling the hydraulic gradient of the flow field and reacts with the ore to form uranium-bearing solution. To reduce leaching dead angle in the process of leaching, each pumping and injection unit should achieve uniform leaching at the end of production, and appropriate pumping and injection mode should be adopted for pumping and injection wells of each unit in the mining area. In this paper, on the basis of the actual production data of a sandstone uranium mine, we established the unit flow model of ISL uranium mining area by using GMS software. The unit flow balance of 72 boreholes in the whole mining area was analyzed and optimized through the model. The concept of flow microbalance of pumping and injection unit in the mining area is put forward for the first time, and the calculation equation of supply and receive the flow of pumping and injection well is determined. The calculation and analysis process of flow microbalance of pumping and injection unit in mining area is established. The simulation results showed that the application effect of the model was good, and the correlation coefficient of the solute transport model reached 0.8.

Influence of blade leaning on hydraulic excitation and structural response of a reversible pump turbine

Blade leaning is commonly seen in the runner design of reversible pump turbines which operate under varying conditions. However, there is no certain law in determine the leaning mode and level. Considering performance, hydraulic excitation and structural response, five runners with strong rotational (RL+), rotational (RL), strong counter-rotational (CL+), counter-rotational (CL) and without (NL) blade leaning are compared under high-efficiency condition in pump mode and turbine mode. The head, efficiency, internal flow pressure pulsation and runner stress are comparatively studied. Among the five runners, CL+ runner is found has the highest efficiency as pump when RL+ runner has the highest efficiency as turbine. Pressure pulsation results show that the rotor-stator interaction region is the strongest pulsation source especially for runner and blade frequencies. In pump mode, pressure pulsation intensity decreases when blade leaning mode gradually changes from rotational to counter-rotational. In turbine mode, the NL runner has the strongest pressure pulsation intensity in runner and guide vane. Both rotational and counter-rotational leaning will reduce pressure pulsation. Velocity contours indicate that blade leaning will affect the velocity uniformity especially along rotational direction and cause stronger or weaker local hydraulic excitation. Under hydraulic excitation, RL+ runner suffers the highest equivalent stress as pump while CL runner suffers the highest equivalent stress as turbine. From rotational to counter-rotational blade leaning, the maximum stress moves on the crown from low pressure side to high pressure side. Considering hydraulic excitation and structural response, the strong counter-rotational leaning blade is found better in reversible runner design.

Experimental Investigation of Double-End Pumped Tm, Ho: GdVO4 Laser at Cryogenic Temperature

We describe comparatively cryogenically cooled Tm, Ho: GdVO4 lasers with an emission wavelength of 2.05 μm under continuous wave and pulse operating mode. By varying the transmittance of output couplers to be 0.40 for a continuous wave laser, the maximum output power of 7.4 W was generated with a slope efficiency of 43.3% when the absorbed pump power was increased to 18.7 W. For passively Q-switched lasers, the output characteristics were researched through altering pump mode radius. When the pump mode radius focused into the Tm, Ho: GdVO4 center equaled near 600 μm, the peak power was increased to be the maximum value of 9.9 kW at the absorbed pump power of 11.8 W. The pulse energy of 0.39 mJ was achieved at the same absorbed pump power with repetition of 5.7 kHz.

Study on dynamic stress of pump turbine runner during power failure in pump mode

The power failure process of pumped storage unit is one of the most dangerous transient processes. The unit enters the pumping braking mode and then generation mode after power failure. In this process, the rotating speed changes from the negative direction to the positive direction, and the hydraulic torque of the blade also changes rapidly, resulting in the great change of runner stress. In this paper, the amplitude of dynamic stress and the location of stress concentration of runner were calculated and analysed to evaluate the safety of runner in the process of power failure in pump mode. The coupling method of one-dimensional pressure wave calculation and three-dimensional flow simulation is used to predict the change of hydraulic loads and the fluid-structure-interaction method is used to calculate the dynamic characteristics of runner. It is found that the position of stress concentration changes in the process of rapid decrease of rotating speed to zero.