Pump Design Research Articles

Flow pulsation characteristics of variable displacement piston pump considering coupling effects cavitation bubble and swash plate inclination angle vibration

Variable-displacement piston pumps, in comparison with quantitative pumps, offer high volumetric efficiency, energy savings, and variable displacement advantages. The outlet flow pulsation of these pumps is influenced by several factors, including swash plate inclination angle vibration, cavitation bubbles, flow distribution structure, and valve control structure. This complexity poses challenges in accurately predicting the flow pulsation at the outlet of variable-displacement piston pumps. In response to this challenge, a novel outlet flow pulsation model for variable-displacement piston pumps is proposed, taking into account the coupling effects of cavitation bubbles and swash plate inclination angle vibration, building upon an existing model. Initially, the effects of cavitation bubbles and swash plate inclination vibrations on flow pulsation were analyzed. Subsequently, a comprehensive flow pulsation model for variable-displacement piston pumps was developed, considering the coupling effects of cavitation bubbles and swash plate inclination angle vibrations. This model was compared with three other existing flow pulsation models. The accuracy of the results was validated using a constructed test bench, with an accuracy improvement of approximately 12% compared to traditional theoretical models. Finally, an optimization model for outlet flow pulsation was proposed. The structural parameters of the valve plate, aimed at minimizing flow pulsation, were determined using the multi-agent particle swarm optimization algorithm. These findings underscore the importance of considering the coupled effects of cavitation bubble and swash plate inclination angle vibration in the design optimization process for reducing low-flow pulsation. This study provides a theoretical foundation for the design of variable-displacement piston pumps with minimized vibration and noise levels.

Additive manufacturing in fluid power with novel application to hydraulic pump design

AbstractAdditive Manufacturing (AM) enhances component functionality in engineering. This study explores AM benefits for hydraulic pumps, by reviewing literature on fluid power and existing AM successes in pumps, pipes, and manifolds. While hydraulic pump research is scarce, the study redesigns a pump, mirroring successes in other hydraulic areas. Predicted outcomes include a 45-85% pressure drop reduction, 35% weight reduction, and fewer parts compared to traditional pumps, achieved with minor design changes. Larger-scale redesigns promise even greater improvements.

Analysis of the Cooperation of a Compressor Heat Pump with a PV System

The decarbonization of heating systems is one of the present political and legislative directions of the European Union and its Member States. The main activities concern the energy performance of buildings and energy efficiency. The mentioned UE directives are the basis for the financial support of high-emission fossil fuel thermal energy source replacement with emission-free ones, in particular heat pumps. Other aspects are the support of PV installations and the thermal insulation of buildings. 85% of EU buildings were built before 2000, and among those, 75% have poor energy performance. Therefore, a significant number of buildings have only high-temperature wall radiators, and this was a motivation to prepare this article. The main innovation of this research was a new theoretical design of a high-temperature heat pump based on ecological refrigerants. The presented solution allows wall radiators to receive a hot water supply with temperatures of up to 85 °C during external temperatures of up to −20 °C. Typical heat pumps do not have these kinds of parameters, so the authors decided to verify the possibility of operating this device in such a wide temperature range. Another important aspect was the analysis of PV support. Finally, this paper investigates the possibility of heating an energy-efficient house with the newly designed high-temperature heat pump. Depending on the location in Poland, i.e., Suwałki, Warsaw, and Wrocław, the total electric energy supplied to the compressors was 2538–3364 kWh. The energy provided by the PV to supply power to the compressors is 482–570 kWh. The achieved PV energy self-consumption is 16.9–19.0%. The Seasonal Coefficient of Performance (SCOP) of the heat pump is 1.825–2.038 without PV and 2.515–2.970 with PV.

Design, construction, and field testing of a spiral water wheel pump

The global expansion in farmland and the increase in the world population has compounded the need for more efficient water use. The spiral water wheel pump can be a valuable and low-cost option for pumping water for surface and subsurface irrigation for farmland near flowing water bodies. This low-cost water-lifting device, which uses the kinetic energy of a flowing stream/river to lift water to homes and farmlands, can help smallholder farmers expand the growing season into the dry season. It is more cost-effective than conventional energy sources. It can be used in areas with limited access to electricity or fossil fuels because the energy of pumping is derived from the kinetic energy of flowing water. Its simplicity, adaptability, and low maintenance requirements make it a valuable tool for communities seeking water security and improved livelihoods. The main objective of this study was to develop performance curves for a version of the pump fabricated from polyvinyl chloride (PVC) and wood, materials that are readily accessible to smallholder farmers in Africa, to optimize its performance for different field conditions. Laboratory and field tests were performed in Illinois, United States of America, and Sierra Leone, West Africa, with pumps with several pipe diameters/pipe configurations and wheel diameters. During the laboratory tests, a 0.6m diameter single-layer pump with a 2.5cm pipe diameter (18 coils) lifted water to a maximum height of 3.4m. When a 3.8cm pipe diameter (10 coils) was used, the maximum height was reduced to 2.7m. Field tests at an experimental site in Fulton County, Illinois, generated a maximum height of 3.4m and 3.1m when 2.5cm pipe diameters were used on 1.22m and 0.6m diameter wheels, respectively. In Sierra Leone, the maximum height generated was 16m and 8.5m for the 1.22m and 0.6m diameter wheels, respectively, with a 1.9cm pipe diameter. In all the field tests, the pumps only worked when the water velocity exceeded 0.6 ms-1, smaller streams with a velocity less than 0.6 ms-1 can be channeled if necessary. These results indicate that this pump can improve dry season productivity for farmland near the flowing water bodies in developing countries like Sierra Leone. Key words: Wheel diameter, pipe diameters, pipe configuration, discharge rate, stream velocity

Accelerating the design of gerotor pumps using interactive tools and fast simulation

Accelerating the design of gerotor pumps using interactive tools and fast simulation

Optimal design of fast adiabatic topological pumping in modulated lattices

Utilizing synthetic dimensions generated by spatial or temporal modulation, topological pumping enables the exploration of higher-dimensional topological phenomena through lower-dimensional physical systems. In this Letter, we propose a rational design paradigm of fast adiabatic topological pumping based on 1D and 2D time-modulated discrete elastic lattices. First, the realization of topological pumping is ensured by introducing quantitative indicators to drive a transition of the edge or corner state in the lattice spectrum. Meanwhile, with the help of limiting speed for adiabaticity to calculate the modulation time, a mathematical formulation of designing topological pumping with the fastest modulation speed is presented. By applying the proposed design paradigm, topological edge–bulk–edge and corner–bulk–corner energy transport are achieved with 11.2 and 4.0 times of improvement in modulation speed compared to classical pumping systems in the literature. In addition, applying to 1D and 2D space-modulated systems, the optimized modulation schemes can reduce the number of stacks to 5.3% and 26.8% of the classical systems while ensuring highly concentrated energy transport. This design paradigm is expected to be extended to the rational design of fast topological pumping in other physical fields.

Study on the cantilever ratio optimization of high-temperature molten salt pump for molten salt reactor based on structural integrity

The high-temperature molten salt pump is the core equipment in the small modular molten salt reactor with media temperatures up to 700 °C. The cantilever ratio of the molten salt pump is usually large. Excessively large cantilever ratios cause increased deformations and rotational amplitudes at the impeller, thus affecting the operational stability of the main pump; small cantilever ratios cause heavy temperature gradients, thus affecting the structural integrity evaluation. This paper used numerical simulation methods to calculate and analyze the temperature field, stress, and structural integrity, optimized the pump shaft cantilever length of the original scheme based on structural integrity using the dichotomy method, and analyzed the rotor dynamics of the optimization results. The results of this study show that the thermal expansion load caused by the temperature difference has a significant mechanical effect on the structure; the first-order critical speed of the rotor system of the optimized schemes has been improved, and the amplitude of the unbalanced response has been significantly reduced, which not only improves the operational stability of the rotor, also contributes to the compact design of the main pump of a small modular molten salt reactor.

The effect of non-uniform inlet boundary conditions on the performance of the multiphase pump

Multiphase pump is an important equipment for oil and gas transportation. The gas-liquid distribution pattern at the inlet of a multiphase pump is crucial to its performance. We propose through an experiment that slug flow and annular flow are the main forms of gas-liquid distribution at the inlet of multiphase pumps. The effects of different flow patterns on the performance of multiphase pumps were investigated through numerical simulations and experimental tests. The results show that the multiphase pump is best adapted to the homogeneous bubble model, followed by the elastic flow and poorly by the annular flow. The energy conversion characteristic of annular flow is poor, and the higher the GVF is, the more obvious this characteristic is. The pressure distribution in the outlet region of the guide vane of the slug flow model is the most inhomogeneous, thus creating a larger vortex scale. The decrease in pressurization of the annular flow is most obvious with increasing GVF. At 30 % GVF, it decreased by 43 kPa compared to the uniform bubble flow model. The different flow patterns have a large effect on the impeller performance, but the distribution of the gas-liquid two-phase at the guide vane outlet tends to stabilize. The significance of this study is to further understand the performance of the first stage impeller of multiphase pumps under special working conditions, and then provide reference for the overall design of multistage pumps to broaden the scope of multiphase pump applications.

Liftoff of a soft-actuated micro-aerial-robot powered by triboelectric nanogenerators

Aerial insects can nimbly navigate in cluttered natural environments while they interact with delicate objects such as flowers and leaves. To achieve insect-like agility and robustness, power dense dielectric elastomer actuators (DEAs) have been developed for driving sub-gram micro-aerial-vehicles (MAVs). However, despite exhibiting muscle-like bandwidth and resilience, DEAs require a high driving voltage in the range of 1 – 2 kilovolts. This requirement poses substantial challenges for developing compact boost electronics and energy sources, which prohibit power autonomous operations of soft-actuated sub-gram MAVs. Here, we develop a compact and high power triboelectric nanogenerator (TENG) that can effectively charge a high-voltage DEA and enable the liftoff of a soft-actuated MAV. We propose an In-plane Charge Pump (ICP) design that can deliver over 1500 V and 110 mW without requiring a secondary charge pump or magnetic circuit components such as inductors or transformers. Compared to conventional free-standing mode TENGs, our ICP design shows a 280 % and 920 % increase in voltage and energy generation, respectively. When this TENG powers a DEA-driven MAV, the 160 mg robot achieves liftoff with a lift-to-weight ratio of 1.75. This result highlights the potential of powering high-voltage microrobots with energy-harvesting devices.

Structural design and characteristic analysis of three-oil port axial piston pump

Structural design and characteristic analysis of three-oil port axial piston pump

Multifactor response-based optimization for enhancing cavitation performance of short injection self-priming pumps

As the heart of the water supply systems, the energy conversion efficiency of the self-priming pumps with built-in injection system under overload conditions is extremely affected by cavitation problems. This study focuses on a typical short-type injection self-priming pump devoted to improve the pump performance, especially to solve the cavitation problem under overload conditions. Through a two-factor, five-level orthogonal test that combines numerical simulation and experimental validation, the influence of key structural parameters within the ejector on cavitation performance and energy characteristics are analyzed. The results demonstrate the high level accuracy of numerical simulation, as indicated by the consistency and small error between the numerical results and the experimental results for head, efficiency, and power under full flow conditions. Regression analysis based on the orthogonal test results reveals significant correlations between the hydraulic performance of the pump and the nozzle throat diameter and nozzle outlet diameter. Under overload conditions, the high-speed jet generated by the injector induces a negative pressure at the effuser and nozzle, leading to cavitation at the effuser throat and nozzle outlet. Employing appropriate structural parameters, particularly the effuser throat diameter and nozzle outlet diameter, proves effective in increasing the operating flow range. This in turn improves the energy characteristics of the entire hydraulic system. The optimal combination identified for the ejector's structural parameters in this study is a nozzle outlet diameter of 8.2 mm and a throat diameter of 18 mm. This provides theoretical insights for the optimal design of short-type jet self-priming pumps, holding practical significance in engineering applications.

The cavitation characteristics of aerospace high-speed centrifugal pumps with different tip clearance

This study investigates the Tip Clearance Cavitation (TCC) characteristics of three different Tip Clearances (TC) (0.4, 0.6, 0.8) and five inlet negative pressure conditions Pj = (− 20–60)kPa to improve the reliability of the aerospace high-speed centrifugal pump during in-orbit operation, based on the premise of good agreement between the TC 0.6 test curve and the simulation performance curve. Under negative pressure and high-speed conditions, the variation gradient of cavitation characteristics with various inlet negative pressures is non-linear and has a sudden change, but the trend becomes stable after the inlet negative pressure drops to a certain stage. The tip clearance cavitation characteristics vary from the blade surface cavitation characteristics due to the difference in forces on both sides. This study is a proper starting point for the design of aerospace power pumps.

Centrifugal compressor design and cycle analysis of large-scale high temperature heat pumps using hydrocarbons

Using natural refrigerants in heat pumps, including hydrocarbons, is becoming attractive because of the tightening regulations concerning synthetic refrigerants. In the literature there is lack of studies investigating detailed component design, including compressor design when using hydrocarbons. This study investigates numerically centrifugal compressor design with hydrocarbons for large-scale high-temperature heat pumps. The compressor analysis was combined with a thermodynamic analysis of a two-stage heat pump. The effect of temperature lift and flash intercooler temperature on compressor sizing, rotational speed, efficiency, axial force, and Mach number were investigated. Generally, the use of hydrocarbons with five carbon atoms resulted in higher coefficient of performance and required lower compressor rotational speeds and larger compressor dimensions when compared to the hydrocarbons with four carbon atoms. The simulated rotational speeds were ranging from 8 krpm to 30 krpm, impeller diameters from 0.15 m to over 0.7 m and compressor efficiencies from 77% to over 85%. The use of cyclic molecules, namely cyclopentane and cyclobutene resulted in the highest heat pump coefficient of performance. Also, the flash intercooler temperature had a notable effect on the compressor design and axial force which has to be taken into account in heat pump cycle design.

A Computational Investigation of the Effects of Temporal Synchronization of Left Ventricular Assist Device Speed Modulation with the Cardiac Cycle on Intraventricular Hemodynamics.

Patients with advanced heart failure are implanted with a left ventricular assist device (LVAD) as a bridge-to-transplantation or destination therapy. Despite advances in pump design, the risk of stroke remains high. LVAD implantation significantly alters intraventricular hemodynamics, where regions of stagnation or elevated shear stresses promote thrombus formation. Third generation pumps incorporate a pulsatility mode that modulates rotational speed of the pump to enhance in-pump washout. We investigated how the timing of the pulsatility mode with the cardiac cycle affects intraventricular hemodynamic factors linked to thrombus formation. Computational fluid dynamics simulations with Lagrangian particle tracking to model platelet behavior in a patient-specific left ventricle captured altered intraventricular hemodynamics due to LVAD implantation. HeartMate 3 incorporates a pulsatility mode that modulates the speed of the pump every two seconds. Four different timings of this pulsatility mode with respect to the cardiac cycle were investigated. A strong jet formed between the mitral valve and inflow cannula. Blood stagnated in the left ventricular outflow tract beneath a closed aortic valve, in the near-wall regions off-axis of the jet, and in a large counterrotating vortex near the anterior wall. Computational results showed good agreement with particle image velocimetry results. Synchronization of the pulsatility mode with peak systole decreased stasis, reflected in the intraventricular washout of virtual contrast and Lagrangian particles over time. Temporal synchronization of HeartMate 3 pulsatility with the cardiac cycle reduces intraventricular stasis and could be beneficial for decreasing thrombogenicity.

Multifactor and multi-objective coupling design of hydrogen circulation pump

The hydrogen circulation pump (HCP) is an important power component of the hydrogen fuel system, used to recover the unconsumed hydrogen from the anode and transport it back to the inlet of the battery stack to improve the hydrogen utilization efficiency. In this paper, to determine the optimal parameter configuration of the HCP, a multifactor and multi-objective optimization design method is proposed, and the influences of various design parameters on the performance of the HCP are analyzed based on the verified overset grid simulation method. The research results show that the proposed coupling design method can effectively achieve the optimal parameter configuration of the HCP, with diameter-to-pitch ratio κ = 1.47, rotor blade number Z = 3, and helix angle φ = 60°, which is validated using another model with significant performance advantages. In the process of studying the influence of design parameters, it is found that the average flow rate of the HCP is directly proportional to the diameter-to-pitch ratio and the blade number, gradually decreases in the range of helix angle from 0° to 22.5°, and increases in the range of helix angle from 22.5° to 60°. The flow pulsation value and pressure pulsation value of the HCP are less affected by the diameter-to-pitch ratio, decrease with the increase of the blade number, and show a trend of first increasing and then decreasing with the increase of the helix angle.

Study on the efficiency characteristics of a stacked cone two-dimensional piston pump

This paper proposes a two-dimensional piston pump with a stacked cone-roll structure. The pump rotates continuously while also moving back and forth in the axial direction. It utilizes the suction and discharge ports to alternate the flow of oil, ensuring proper distribution and completing the suction and discharge process. The operating mechanism of the piston pump was analyzed, and subsequently, a mathematical model was developed to determine its mechanical efficiency and volumetric efficiency was established. Furthermore, the AMESim simulation model was built to obtain the variation curves of the input torque and leakage flow of the drive unit under different load pressures and rotational speeds. Ultimately, a prototype was fabricated and a test apparatus was assembled to evaluate the volumetric efficiency and mechanical efficiency under varying speeds and load pressures. The empirical findings were largely congruent with the modeling findings, indicating that the volumetric efficiency rose from 86.3% to 92.2% as the speed increased, whereas the mechanical efficiency declined from 93.8% to 89.1% under a constant load pressure. Under constant speed conditions, the volumetric efficiency of the stacked tapered roller-type two-dimensional piston pump fell from 94.1% to 91.3% as the load pressure increased. However, the mechanical efficiency grew from 87% to 90.2%. These findings confirm the practicality of the pump design.

Optimization of pump transient energy characteristics based on response surface optimization model and computational fluid dynamics

The global energy shortage is increasingly becoming a problem of major concern worldwide. Since the pumps represent the largest part in the energy conversion devices, improving their energy characteristics is very important for energy conservation and efficiecy. However, the traditional pump design methods have generally overlooked the transient flow characteristics inside the pumps leading to high hydraulic losses and low operatinal efficiency, especially in applications that have pronounced transient effects. To address this problem, a novel approach is proposed in this paper which combines the response surface optimization method with the computational fluid dynamics (CFD) technology to optimize the energy characteristics of pumps during the transient processes. The main objective of the study is to enhance the internal flow state and the transient energy performance of the pump during the start-up process. A comparative analysis is conducted on the energy characteristics and the internal flow field of a model pump before and after the optimization, thereby validating the effectiveness of the proposed energy characteristics optimization method. The numerical results reveal that the inlet placement angle (α), the outlet placement angle (β), the blade envelope angle (φ), and the blade thickness coefficient (θ) significantly impact the weighted average head and weighted average efficiency of the pump. After optimization, the weighted average head and the weighted average efficiency of the pump increase by 2.97% and 8.91% respectively, while the transient efficiency of the pump at all times surpasses that of the traditional, non-otimized design approach. These research findings provide valuable insights for enhancing the performance of the pumps oerating in the transient flow conditions.

A Graphical Approach to Visualize and Interpret Biochemically Coupled Biomechanical Models.

The last decade has seen the emergence of progressively more complex mechanobiological models, often coupling biochemical and biomechanical components. The complexity of these models makes interpretation difficult, and although computational tools can solve model equations, there is considerable potential value in a simple method to explore the interplay between different model components. Pump and system performance curves, long utilized in centrifugal pump selection and design, inspire the development of a graphical technique to depict visually the performance of biochemically-coupled mechanical models. Our approach is based on a biochemical performance curve (analogous to the classical pump curve) and a biomechanical performance curve (analogous to the system curve). Upon construction of the two curves, their intersection, or lack thereof, describes the coupled model's equilibrium state(s). One can also observe graphically how an applied perturbation shifts one or both curves, and thus how the other component will respond, without rerunning the full model. While the upfront cost of generating the performance curve graphic varies with the efficiency of the model components, the easily interpretable visual depiction of what would otherwise be nonintuitive model behavior is valuable. Herein, we outline how performance curves can be constructed and interpreted for biochemically-coupled biomechanical models and apply the technique to two independent models in the cardiovascular space. The performance curve approach can illustrate and help identify weaknesses in model construction, inform user-applied perturbations and fitting procedures to generate intended behaviors, and improve the efficiency of the model generation and application process.

Thermodynamic analysis of a dual-pressure evaporation high-temperature heat pump with low GWP zeotropic mixtures for steam generation

High-temperature heat pumps (HTHPs) have gained attention due to their economic and environmental benefits in utilizing industrial waste heat for steam generation. This study focuses on improving the HTHPs’ performance by employing two-stage separation and dual-pressure evaporation technology in the auto-cascade heat pump cycle. Additionally, binary zeotropic refrigerant mixtures with low-GWP are selected using the polar perturbed-chain statistical associated fluid theory (PC-SAFT) equation of state. The findings indicate that the R1234ze(E)&R1233zd(E) refrigerant mixture outperforms other potential alternatives, exhibiting a thermodynamic effectiveness 0.85%–1.86% higher than the benchmark mixture, R134a&R245fa. The improved cycle demonstrates significant enhancements, achieving a 45.17% increase in heat source utilization efficiency and a 24.48% improvement in COP compared to the basic auto-cascade cycle. Effective temperature matching between refrigerant mixtures and heat sources/sinks is guaranteed in the improved cycle. Moreover, a parameter analysis reveals that increasing the subcooling degree of the cascaded heat exchanger and the separation dryness fraction at separator 2 enables improvements in both COP and heat source utilization efficiency. These findings provide valuable insights into the design of steam generation heat pumps and the selection of refrigerant mixtures.

Study on Impeller Optimization and Operation Method of Variable Speed Centrifugal Pump with Large Flow and Wide Head Variation

The benefits of variable speed centrifugal pumps include high stability, a broad operating range, and adjustable input power. In water distribution systems, the pump units are increasingly using variable speed technology. The energy-saving features and operational stability of the pump station are directly impacted by the hydraulic performance and the operation strategy. In this study, CFD numerical analysis and model tests were adopted to design and evaluate the hydraulic performance of the variable speed centrifugal pump with large flow and wide head variation in Liyuzhou Pump Station. Under the premise of ensuring the wide head variation, the optimized centrifugal pump met the requirements of hump margin and efficiency in the high head zone and the cavitation margin in the low head zone. The test results demonstrated that the operational range of the variable speed centrifugal pump was successfully widened by reasonable hydraulic parameters selection and impeller optimization. The safe and efficient operational range of the variable speed unit was determined by means of taking the performance requirements of the pump’s maximum input shaft power, cavitation characteristics and pressure fluctuation into consideration. The scientific and reasonable operational path to meet the various operation needs was also investigated and determined for the pump station’s actual operation needs. A high efficiency, safe operation, and a simplified control logic were achieved by using the operational path, which makes it a reasonable potential guide for hydraulic design and operational optimization of variable speed centrifugal pumps with large flow and wide head range.