Pump Design Research Articles

Synthesizing gas-filled anti-resonant hollow-core fiber Raman lines enables access to the molecular fingerprint region

The synthesis of multiple narrow optical spectral lines, precisely and independently tuned across the near- to mid-infrared region, is a pivotal research area that enables selective and real-time detection of trace gas species within complex gas mixtures. However, existing methods for developing such light sources suffer from limited flexibility and very low pulse energy, particularly in the mid-infrared domain. Here, we introduce a concept that is based on the combination of an appropriate design of near-infrared fiber laser pump and cascaded configuration of gas-filled anti-resonant hollow-core fiber technology. This concept enables the synthesis of multiple independently tunable spectral lines, with >1 μJ high pulse energies and a few nanoseconds pulse width in the near- and mid-infrared regions. The number and wavelengths of the generated spectral lines can be dynamically reconfigured. A proof-of-concept laser beam synthesized of two narrow spectral lines at 3.99 µm and 4.25 µm wavelengths is demonstrated and combined with photoacoustic modality for real-time SO2 and CO2 detection. The proposed concept also constitutes a promising way for infrared multispectral microscopic imaging.

Design and Optimization of a Permanent Magnet Synchronous Motor for a Two-Dimensional Piston Electro-Hydraulic Pump

A two-dimensional (2D) piston electro-hydraulic pump has been proposed further to enhance the power density of the electro-hydraulic pump. The 2D piston pump, characterized by high power density and a slender shape, is embedded within the stator of the motor in a co-rotor configuration where the piston and the motor’s rotor are in tandem. The intimate design of the hydraulic pump and the motor results in a coupling between the two, with intricate relationships and influences existing between the geometric parameters of the piston pump and the dimensions of the motor’s rotor. Based on the operational requirements and structure of the 2D piston pump, a permanent magnet synchronous motor (PMSM) designed for use with a 2D piston electro-hydraulic pump is developed. This study examines the impact of the motor’s stator iron core geometric parameters on both the electromagnetic and mechanical properties of a PMSM and completes the necessary performance validations. The optimization objectives of the motor are determined through an analysis of the influence of the key parameters of the rotor and stator on torque, torque ripple, and motor loss. A surrogate optimization model is constructed using a metamodel of optimal prognosis (MOP) to optimize the torque, torque ripple, and motor loss. Evolutionary genetic algorithms are utilized to achieve the multi-objective optimization design. A finite element simulation is used to compare the electromagnetic performance of the initial motor and optimal motor. Based on the optimal motor parameters, a 2.5 kW motor prototype is manufactured, and the experimental results validate the feasibility and effectiveness of the motor design and optimization.

Two-dimensional non-Abelian Thouless pump

Non-Abelian Thouless pumps are periodically driven systems designed by the non-Abelian holonomy principle, in which quantized transport of degenerate eigenstates emerges, exhibiting noncommutative features such that the outcome depends on the pumping sequence. The study of non-Abelian Thouless pump is currently restricted to 1D systems, while extending it to higher-dimensional systems will not only provide effective means to probe non-Abelian physics in high-dimensional topological systems, but also expand the dimension and type of associated non-Abelian geometric phase matrix for potential applications. Here, we propose the design and experimental realization of 2D non-Abelian Thouless pumps on a photonic chip with 2D photonic waveguide arrays, where degenerate photonic modes are topologically pumped simultaneously along two real-space directions. We reveal the associated non-Abelian group and experimentally demonstrate the non-Abelian feature by measuring the pumping sequence dependent output. The proposed 2D non-Abelian Thouless pump shows promising applications for robust optical interconnections and optical computing.

Unidirectional Flow Through Time-Dependent Cross-Sectional Areas of a Compliant Tube and a Valve: A Nonlinear Model

This work investigates the conditions for net flow generation by a straight tube with a cross-sectional area harmonically varying in time that connects two tanks—a problem that is mainly found in the design of impedance pumps. By assuming a quasi-one-dimensional flow and applying continuity and momentum equations, a first-order differential equation with respect to the flow rate is derived and presented for the first time, including a nonlinear term that is responsible for net flow rate generation. Namely, the net flow rate is found to be nonzero (as is the nonlinear term) if the cross-sectional areas of the two tanks are unequal and one of them is smaller than that of the straight tube. In this case, the flow is directed from the smaller to the larger tank and the net flow rate increases with the frequency of the tube’s cross-sectional area variation. In contrast, when the tanks’ cross-sections are equal, the net flow is generated only if a valve is installed, e.g., at one end of the tube, due to the large asymmetries imposed in the hydraulic losses with respect to the tube mid-length. Compared with constant valve opening, the net flow rate is augmented significantly if the valve opening is time-dependent. By employing the same equation, the flow rate of an intra-aortic counter-pulsating balloon pump is also examined, in which the valve (representing the aortic valve) opens during the shrinkage of the tube, and it is shown that the net flow rate increases with the frequency and amplitude of the tube’s cross-sectional area. Conclusively, the harmonic oscillation in time of a tube’s wall can cause unidirectional flow only if asymmetric losses are present with respect to its mid-length.

Numerical Simulation and Model Test on Pressure Fluctuation and Structural Characteristics of Lightweight Axial Flow Pump

In order to explore the relationship between the hydraulic performance, pressure pulsation, and structural characteristics of lightweight axial flow pumps, this paper takes the axial flow pump as the research object and analyzes pressure pulsation and structural characteristics by changing the blade length and thickness to realize the lightweight design of the axial flow pump impeller. Compared with the initial scheme (Scheme 1), the mass of the impeller is reduced by 17.2% (Scheme 2) and 29.9% (Scheme 3), respectively. The lightweight axial flow pump (Scheme 2 and Scheme 3) has a lower pressure pulsation amplitude at the impeller outlet monitoring point under large flow conditions. After the lightweight design of the axial flow pump impeller, the blade becomes shorter, the mass becomes lighter, and the cavitation performance will become worse. The maximum equivalent stress of Scheme 2 and Scheme 3 is increased by 2.8% and 31.9%, respectively, compared to Scheme 1. The maximum deformation of Scheme 3 increased by 27% compared to Scheme 1. This research can provide guidance for the lightweight optimization design of the axial flow pump.

Lubrication, Friction and Wear Characteristics of Textured Surface Slipper Pairs in Axial Piston Pumps

The study investigates the impact of textured surface parameters and pump operating parameters on the friction performance of slipper pairs in axial piston pumps. The orthogonal experimental scheme was developed, and the influence of several factors was explored, such as rotational speed, area ratio, micro-pit shape, diameter, depth-to-diameter ratio and film thickness. Optimal dimension combinations of the micro-pit were identified by numerical simulation and standard pin–disk friction experiment. In the pin–disk friction pair test, the friction coefficient of the textured surface compared to the smooth surface showed a maximum average friction reduction rate of 26.974%. Under various pump pressures (4, 8, 12 MPa) and pump displacements (10, 20, 35 L/min), the friction reduction rates of the textured surface slipper pairs (texture diameter 500 µm, depth 250 µm, area ratio 20%) ranged from 0.78% to 18.13%. The study underscores the importance of surface texture in enhancing the operational efficiency and reliability of axial piston pumps, offering valuable insights for the design and maintenance of hydraulic pumps.

Design and Performance Test of Four-Chamber Series–Parallel Piezoelectric Pump

In order to improve the output performance of multi-chamber piezoelectric pumps, this paper proposes a novel design for a four-chamber series–parallel piezoelectric pump, based on the characteristics that the parallel chamber structure significantly increases the output flow rate, and the series chamber structure effectively improves the output pressure. The theoretical output flow rate and pressure of the four-chamber series–parallel piezoelectric pump were calculated, and a prototype was fabricated. Tests were conducted to compare the liquid transport performance of piezoelectric pumps with three different structures: series, parallel, and series–parallel. The results show that, when transporting liquid, the output flow rate of the four-chamber series–parallel structure increased by up to 13.3% compared to the four-chamber series structure, reaching a maximum of 767 mL/min. Additionally, the maximum output pressure of the series–parallel structure increased by 43.4% compared to the four-chamber parallel structure, reaching 42.3 kPa. The four-chamber series–parallel design combines the advantages of both series and parallel configurations, improving the output performance of the piezoelectric pump and providing a reference for the structural design of multi-chamber piezoelectric pumps.

Flow induced acoustic characteristics analysis of propulsion pump by indirect acoustic variable method and FEM

The acoustic characteristics of water-jet propulsion pumps present significant challenges, primarily due to the interaction between flow and high-speed rotating impellers wall. Notably, such complicated turbulence induced acoustic sources by brings great difficulty to identify and control. This paper firstly analyzes the flow characteristics of the propulsion pump by using the scalable Hybrid RANS-LES model. Subsequently, an indirect acoustics variable method based on Lamb vector divergence is proposed to characterize acoustic sources caused by multiscale turbulence. The effectiveness and advantages of indirect acoustics variable method are evaluated through comparison with the acoustic finite element method and experimental results. The proposed indirect acoustics variable method demonstrates the ability to accurately quantify the contribution of turbulent flow to acoustic sources. Furthermore, the intensity of acoustic sources in different flow regions can be obtained through volume integrals, which can serve as optimization parameters in the initial hydraulic design of propulsion pumps. This study provides a novel approach for predicting turbulent noise and offers guidance for the design of low-noise propulsion systems.

Evolution mechanism of internal flow in the hump region and hump optimization of axial-flow reactor coolant pump

The Nuclear Reactor Coolant Pump (RCP) serves as a pivotal equipment in nuclear power plants, and its operational reliability is directly linked to the overall safety of the plant. When operating in the hump region, axial-flow reactor coolant pumps inevitably experience significant vibration and noise. Therefore, it is necessary to study the internal flow characteristics in the hump region to achieve effective control and increase the hump margin, keeping it away from the normal operating region. This study conducted analyses of pressure pulsation characteristics under various flow rates through experimentation. Additionally, numerical simulations were employed to scrutinize the internal flow of the pump under corresponding flow rates. Research has found that the disturbance of intermediate frequency signals is the main reason for the increase in pressure fluctuations in the hump region, rooted in the annular flow at the impeller inlet and vortex phenomena in the flow channel. Subsequently, the performance of the hump region was improved by optimizing the design of the vane inlet attack angle. The conclusions drawn from this study provide insights and a foundation for the optimal design of reactor coolant pumps.

Совершенствование конструкций установок струйных насосов для добычи нефти

The characteristics of jet pump installations are given, which are used mainly for low-yield wells in oil production whose flow rate is less than 10 m3/day. It is noted that jet pump installations have a relatively low efficiency of not exceeding 0.35, and it is almost equal to the efficiency of electric drive pump installations and downhole rod pump installations when extracting oil from wells with low flow rates of up to 20 m3/day. The advantages of jet pump installations over other types of downhole pumping installations in difficult oil production conditions are shown. With flow rates up to 150 m3/day. Costs for oil production using jet pump installations are minimal compared to other installations. A brief analysis of the designs of jet pumps, their main overall dimensions and weight is provided. A brief overview of scientific, technical and patent literature on jet pump installations is given. By changing the design of nozzles, confusers, diffusers, working chambers of jet pumps, as well as improving the jet pump installations as a whole when used in tandem with other types of well installations, their productivity, operating efficiency and reliability can be increased. It is noted that the parameters of jet pumps can be obtained by calculation based on the theory of mixing two flows, the theory of jet propagation in a mass of stationary or moving liquid and the mechanics of bodies of variable mass. The main design parameters of jet pump units are feed, pressure, ejection coefficient, power and efficiency. These parameters can also be determined experimentally. A laboratory jet pump unit has been developed. Experiments have shown that with an increase in the flow rate of the working fluid, the flow rate of the mixture and the working pressure, the ejection coefficient and efficiency decrease. In the future, experiments will be continued with various designs of jet pump elements.

Transient flow and noise characteristics of vortex-turbulence-noise interaction in centrifugal pump

Centrifugal pump operation noise is an avoidable common phenomenon in engineering practices, and its characteristics are closely influenced by the flow characteristics of the fluid. In this paper, a numerical simulation of centrifugal pump operation with different flow rates is carried out using the detached eddy simulation turbulence model and compared with the experimental results. Then the noise source and far-field radiated noise characteristics of the centrifugal pump are investigated using Lighthill’s analogy. The results show that the noise of centrifugal pump is closely related to the flow characteristics of impeller, especially the generation and development of vortex. The relationship between turbulent kinetic energy (TKE) and vortex is complex, involving the generation, development and shedding of vortex. The influence of flow rate variation on vortex structure in impeller is studied by vortex transport equation. It is found that the relative vortex stretching (RVS) term is the main driving force of vortex distribution. The distribution of the Coriolis force (CORF) term is mainly concentrated in the inlet and outlet areas of the flow channel, which is related to the rotational motion of the impeller and the dynamic characteristic of the fluid. The power spectral density inside the impeller is mainly concentrated in the low frequency region, indicating that the low frequency noise component is dominant in energy. The directivity curve of far-field noise pressure level is influenced by hydrodynamic effect, impeller rotation direction and pump design structure, and will have a certain deviation. The spectral curve analysis of velocity, vorticity, pressure and sound pressure level shows that these physical quantities have strong correlation on the spectrum, in which the low frequency component is large, and the high frequency component is complex and volatile.

Analysis of variable speed operating range of centrifugal pump with large flow and wide head variation

Abstract The advantages of variable speed centrifugal pump include its broad operating range, wide operating efficiency zone, high operational stability, and regulative characteristics of input power. When pump station has characteristics such as large flow rate changes, large pump head changes, the conventional fixed speed centrifugal pump cannot meet requirements of safe and stable operation under characteristic pump conditions. In order to ensure the safe and stable operation of the pump station within the operation range, the variable speed operation strategy of centrifugal pumps is adopted to enhance its wide amplitude adjustment capability and efficient operation. This paper uses an 8MW centrifugal pump with wide head range in China to analyze the factors that influence the operating range of pump unit in detail. The results indicate that the variable speed pump unit’s safe and effective operating range is determined by the cavitation margin, hump margin, speed range, and pump maximum input power. The hydraulic design can improve the hump safety margin and cavitation characteristics of the operating zone, and then expand the operating range of the pump unit. Meanwhile, increasing the static suction head, reducing the hump margin, controlling pump head amplitude, and appropriately increasing the maximum input power limit are the best ways to extend centrifugal pump’s operating range and improve its adjustable capability. The results can provide reference for parameter selection and hydraulic design of large variable centrifugal pump in the future.

Study on the characteristics of fluid exciting force on impeller of high-speed centrifugal pump under the condition of poiseuille inflow

Abstract The paper adopted the turbulence model of Wall-Model Large Eddy Simulation with improved algebraic form (WMLES S-Omega) to carry out the study on the fluid exciting force on impeller of high-speed centrifugal pump under the conditions of Poiseuille inflow and uniform inflow. The external characteristics and the vibration displacement of the shaft of high-speed centrifugal pump are tested. The results indicated that it is the high matching that the test and numerical external data of high-speed centrifugal pump under the condition of Poiseuille inflow. The test results of vibration displacement of shaft match the fluid exciting force better in terms of waveform and phase difference under the condition of Poiseuille inflow. The contribution degree of force and torque from the shroud inner surface in the X and Y direction is 76.3%, 80.7%, 79.5% and 85% of the resultant force and torque, and its force from the inner and outer surfaces of shroud and hub in the Z direction is 94.3%, and its torque from blades’ surfaces in the Z direction is 98.3%. The study results can provide some theoretical support for the research of fluid exciting force and hydraulic optimization design of centrifugal pump.

Turbulent flow field in maglev centrifugal blood pumps of CH-VAD and HeartMate III: secondary flow and its effects on pump performance.

Secondary flow path is one of the crucial aspects during the design of centrifugal blood pumps. Small clearance size increases stress level and blood damage, while large clearance size can improve blood washout and reduce stress level. Nonetheless, large clearance also leads to strong secondary flows, causing further blood damage. Maglev blood pumps rely on magnetic force to achieve rotor suspension and allow more design freedom of clearance size. This study aims to characterize turbulent flow field and secondary flow as well as its effects on the primary flow and pump performance, in two representative commercial maglev blood pumps of CH-VAD and HeartMate III, which feature distinct designs of secondary flow path. The narrow and long secondary flow path of CH-VAD resulted in low secondary flow rates and low disturbance to the primary flow. The flow loss and blood damage potential of the CH-VAD mainly occurred at the secondary flow path, as well as the blade clearances. By contrast, the wide clearances in HeartMate III induced significant disturbance to the primary flow, resulting in large incidence angle, strong secondary flows and high flow loss. At higher flow rates, the incidence angle was even larger, causing larger separation, leading to a significant decrease of efficiency and steeper performance curve compared with CH-VAD. This study shows that maglev bearings do not guarantee good blood compatibility, and more attention should be paid to the influence of secondary flows on pump performance when designing centrifugal blood pumps.

Experimental study on energy and hydraulic performance of the axial flow pumping device with bell-shaped inlet channel

Abstract Due to the unique inlet design of the axial flow pump device with a bell shaped inlet channel, there is currently insufficient quantitative research on its hydraulic characteristics. This study investigates the hydraulic behavior of a vertical axial flow pumping device equipped with a bell-shaped inlet channel, analyzing various blade angles. Energy, cavitation, runaway, and pressure pulsation characteristics were assessed through meticulous testing on a high-precision test bench. Experimental findings indicate that altering the blade angle of the vertical axial flow pumping device with a bell-shaped inlet channel can influence its overall efficiency to some extent. Moreover, as the pump’s blade angle increases incrementally, the device’s cavitation performance gradually diminishes. Pressure pulsation tests reveal a relatively minor amplitude of pressure pulsation at the impeller outlet, contrasting with a more pronounced amplitude observed at the guide vane outlet compared to the pump outlet. These research results provide valuable insights for the design and optimization of actual pumping stations.

Effect of baffles on internal flow characteristics of double-inhalation centrifugal pumps under low flow conditions

In order to investigate the impact of baffles in the inhalation chamber on the external characteristics and operational stability of a double inhalation centrifugal pump under low flow conditions, the flow field simulation software ANSYS CFX and the shear stress transport formulation were employed to numerically simulate the internal flow field of a double inhalation centrifugal pump with and without baffles. Two models were subjected to performance curve simulation and prediction, with the internal flow field, pressure pulsation, and impeller force of the two models being compared and analyzed under three small flow conditions of 0.6Qd (rated flow), 0.5Qd, and 0.4Qd. The velocity and vortex distribution inside the semi-spiral inhalation chamber, as well as their impact on the flow state in front of and inside the impeller, were analyzed. Research has demonstrated that the addition of baffles can enhance the pump head and efficiency in flow conditions of 0.5Qd–0.8Qd. However, there is a tendency for obstruction of flow in conditions below 0.5Qd. Baffles can reduce the amplitude of pressure pulsation within the impeller and the radial force exerted by the impeller as a whole. Consequently, the incorporation of baffles within the inhalation chamber during flow conditions of 0.5Qd–0.8Qd can enhance the operational efficacy of the pump. Nevertheless, within the flow range of <0.5Qd, the pump's performance will decline. This study serves as a foundation for the design of double inhalation centrifugal pumps with semi-spiral inhalation chambers.

Research on the Internal Flow Characteristics of an Electric Coolant Pump

Abstract To investigate the internal flow characteristics of an automotive electronic coolant pump, numerical simulations were performed utilizing the ANSYS CFX commercial software suite. The study delved into the velocity distribution, pressure pulsation intensity characteristics, and entropy generation of the electronic coolant pump under varying operational conditions. The findings revealed that with an increase in the flow rate, the coolant flow velocity within the pump also escalated. Concurrently, the separation flow at the trailing edge of the blade diminished, while the flow velocity at the trailing edge of the pressure surface escalated. Notably, the impeller and volute emerged as the primary sites generating pressure pulsations, with pressure pulsation intensity within the pump surpassing that of the design condition in off-design scenarios. Furthermore, entropy generation predominantly manifested at the impeller, volute, and front pump chamber locations, with the impeller exhibiting minimal total entropy generation under design conditions. These insights serve as crucial reference points for optimizing the design of automotive electronic coolant pumps.

Influence of axial distance between impeller and diffuser on the hydraulic performance and flow loss characteristics of bulb tubular pump

Abstract Bulb tubular pumps used in regional water transfer projects consume substantial power. Optimizing the geometric parameters of tubular pumps is crucial for enhancing efficiency and minimizing hydraulic losses. ANSYS CFX is used to investigate the axial distance between the impeller and the diffuser on the hydraulic performance and flow loss characteristics of the rear-bulb tubular pump, and the numerical simulation results are compared with the experimental data. Then, the entropy production theory is introduced to analyze flow losses. As the axial distance increases, the diffuser’s rectification effect on the flow at the impeller outlet deteriorates, leading to increased flow losses and decreased head and efficiency of the device. Flow losses in the bulb tubular pump are ranked from largest to smallest as follows: impeller, outflow channel, diffuser, inlet channel. The impeller exhibits the highest entropy production ratio, reaching 61.05% at an axial distance of 25 mm. By elucidating the energy loss distribution of each component under varying axial distances, this paper offers insights for the hydraulic optimization design of bulb tubular pumps.

Research on turbulence model parameters for the prediction of waterjet propulsion pump hydrodynamic performance

Abstract The hydrodynamic performance of waterjet propulsion pumps has an important impact on improving the speed of waterjet propulsion ships. High-precision prediction of the hydrodynamic performance of water-jet propulsion pumps based on CFD is of great significance to improving the pump design quality. Based on the Reynolds-averaged Naiver-Stokes equation, this paper conducts a grid-independence verification on a water jet propulsion pump based on hydrodynamic test data, uses the Latin hypercube sampling method to generate SST k-ω turbulence model parameter space calculation samples, performs steady-state calculation on all samples, analyzes the sensitivity of changes in the parameters of the turbulence model to the prediction of the external characteristics of the waterjet propulsion pump, and finally obtains the influence of changes in the parameters of the turbulence model on the prediction of the external characteristics of the pump. Among them, the sensitivities of the three parameters β *, β1 and a1 are higher. The results show that the prediction accuracy of the external characteristics of the water jet propulsion pump can be effectively improved by correcting these three highly sensitive parameters, and the correction values of the three key parameters are obtained. The prediction error of the external characteristics of the water jet propulsion pump is reduced from 4.3% to less than 2.1%. A feedforward neural network is used to establish a mapping model between the three turbulence model parameters and the head coefficient and power coefficient of the waterjet propulsion pump in order to achieve rapid prediction. The genetic algorithm is applied to optimize the weights, thresholds and other coefficients in the neural network, thereby improving the prediction accuracy. Based on the optimized neural network, the genetic algorithm is used to optimize the three turbulence model parameters, and the optimized coefficients are obtained. The optimized turbulence model parameters are put into the hydrodynamic model for RANS simulation to verify the degree of optimization of the model coefficients by the genetic algorithm.

Multistage Charge Pump Design Methodology for Zero-Crossing-Based Amplifiers

Multistage Charge Pump Design Methodology for Zero-Crossing-Based Amplifiers