Pump Chamber Research Articles

Piezoelectric Actuator-Driven Pulsed Water Jet for Neurosurgery: Laboratory Evaluation with the Swine Model and Implications of Mechanical Properties.

Pulsed water jet is an emerging surgical instrumentation intended to achieve both maximal lesion resection and functional maintenance through preservation of fine vessels and minimal damage to the surrounding tissue. The piezoelectric actuator-driven pulsed water jet (ADPJ) is a new technology that can deliver a precisely controlled uniform and efficient pulsed water jet with minimum water flow. The present study evaluated the ADPJ system in preclinical animal studies in the swine brain, and investigated breaking strength, one of the parameters for mechanical properties, to elucidate the mechanism of tissue selectivity for tissue dissection by the water jet. This system consisted of a pump chamber driven by a piezoelectric actuator, a stainless steel tube, and a nozzle (internal diameter: 0.15 mm). Water was supplied at 6 ml/min. The relationship between input voltage (3-25 V at 400 Hz) and peak pressure was measured using a pressure sensor through a sensing hole. The temporal profile of dissection depth during moving application was evaluated using gelatin brain phantom and swine brain. The dissected specimens were evaluated histologically. The mechanical property (breaking strength) of the swine brain was measured by a compact table-top universal tester. Peak pressure increased linearly with increase in input voltage, which reflected the dissection depth in both the gelatin brain phantom and swine brain. Small arteries were preserved, and minimum damage to surrounding tissues occurred. The breaking strength of the arachnoid membrane (0.12 ± 0.014 MPa) was significantly higher compared with the gray matter (0.030 ± 0.010 MPa) and white matter (0.056 ± 0.009 MPa; p < 0.05). The breaking strength of the gray matter corresponded to that of 3 wt% gelatin, and that of white matter corresponded to a value between 3.5 and 4 wt% gelatin, and the dissection depth seemed to be estimated at 3 to 4 wt% gelatin. The present study suggests that the ADPJ system has the potential to achieve accurate tissue dissection with preservation of blood vessels in neurosurgery. The difference in breaking strength may explain the tissue selectivity between the brain parenchyma and tissue protected by the arachnoid membrane.

Development of an Online Cloud Fog Monitor: Design, Laboratory, and Field Deployment at an Unoccupied Coastal Site in Eastern China

Online detection of cloud water chemistry is a pressing issue in atmospheric outfield observation, with online detection modules representing a significant development direction for cloud water observation. Addressing the common problem of time-delayed errors in manual detection, particularly in the context of cloud water acidity, has remained challenging, with limited understanding and effective solutions available. We developed an Online Cloud Fog Monitor (OCFM) featuring automatic pH and electrical conductivity (EC) detection capabilities, and conducted comprehensive laboratory and field tests. The OCFM utilizes a peristaltic pump, water pipe, and diversion chamber to direct cloud samples to distinct detection chambers, enabling real-time analysis. The diversion chamber is equipped with dual liquid level sensors to segregate and preserve samples once the volume exceeds a predetermined threshold. Calibration results indicate that the instrument's background metal elements do not affect cloud water analysis, and detection occurs within the designed response time. Field tests demonstrate that the OCFM can collect over 50 ml of cloud water, with a response accuracy exceeding 63.6%, though influenced by meteorological conditions. The time-delay error for pH was notably larger than for EC. Comparative analysis with the Caltech Active Strand Cloudwater Collector (CASCC) revealed that the OCFM’s sampling process does not introduce errors, and the online detection accuracy of pH and EC is comparable to manual methods. Additionally, water-soluble ions in samples collected by the OCFM showed no significant differences compared to those collected by CASCC. Overall, the OCFM effectively replaces manual testing, mitigating time-delay errors in chemical property testing. The introduction of this cloud water detector promises to significantly reduce labor costs and economic consumption associated with cloud water observation, thereby facilitating long-term, multi-site observation of cloud water chemistry.

A piezoelectric pump with composite vibrator for bubble resistance

Piezoelectric pumps, as microfluidic drive units, are widely used in microfluidic systems. Due to the fact that most piezoelectric pumps are driven by displacement, the introduction of air bubbles will produce a significant impact on their output performance. To minimize the adverse effect of air bubbles, a piezoelectric pump with composite vibrator (PPCV) is proposed. The composite vibrator consists of the active vibrator and the passive vibrator. By vibrating the passive vibrator in the pump chamber, it prevents bubbles retention. Multi-physics field simulation is established，which verifies the PPCV is feasible. Furthermore, a prototype is fabricated and experimentally investigated. At a voltage of 300 Vpp, the experimental results indicate a maximum output flow rate of 41.4 ml/min and a maximum output pressure of 18.7 kPa. After continuously entering 100 bubbles, the output performance of the PPCV decreases by less than 10 %, indicating that the PPCV owns excellent bubble resistance ability. The PPCV provides a new approach to microfluidic pumping devices.

Research on the Balance Axial Force of the Back Blade of Centrifugal Pump Impeller based on CFD

Abstract One popular way to decrease the pump’s axial force is by utilizing the back blade. In this paper, by changing the number and width of back blades and using CFD 3D simulation technology, the influence law of back blades on pump performance, pump chamber liquid pressure characteristics and axial force characteristics is obtained. By changing the number of the back blade and width of the back blade, this paper adopt CFD 3D simulation technology to study, get pump performance, pump cavity liquid pressure characteristic and the influence law of axial force characteristics. The results show that the pump head and power increase with the increase of the width and number of back blades. However, the efficiency of the pump gradually decreases with the increase of the width and number of back blades. The impeller mounted back blade can change the pressure distribution of liquid of the pump chamber, and affect the axial force of the pump. The size and direction of the axial force change with the number and width of the back blades.

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.

Control System Hardware Design, Analysis and Characterization of Electromagnetic Diaphragm Pump

In this article, a novel electromagnetic diaphragm pump design controlled by an Arduino NANO microcontroller is proposed to pump liquid inside the pumping chamber completely separated from mechanical and transmission parts. The prototype is primarily based on alternating the polarity of two electromagnets that attract or repel a permanent magnet located on a flexible diaphragm. The system hardware layout is completed by electronic components:. an Arduino NANO microcontroller created by Atmel, Headquarters San Jose, California. and display within the cabinet to control the polarization of the electromagnets and exhibit the temperature inside the pump. The electromagnetic pump and control system consist of innovative approaches as a solution for the treatment of unclean water and integration with solar panel systems. In addition, the measurement tests of the electromagnetic pump, including the temperatures of electromagnets and the quantity of the pumped liquid within the chamber, indicate a dependence on the selected speed of the electromagnet’s polarization. The electromagnetic pump achieves high efficiency as a combination of the temperature and the amount of liquid that can be regulated and controlled by the switching speed of the electromagnet’s polarization.

A Novel Downhole Communication Strategy Using Loading Wave Conduction on Sucker-Rod Pumping System for Intelligent Lifting

Summary An effective and accurate downhole communication strategy is crucial for the fabrication of an intelligent lifting system for onshore oil wells. Traditional communication approaches based on the wired cable, acoustic wave, vibration wave, or fluid pressure are usually limited by downhole conditions, and issues such as cumbersome implementation, limited communication, and unstable signal modulation are encountered. Herein, a novel downhole communication strategy is proposed using the loading waves in the sucker-rod pumping system (SRPS). The loading wave is altered at the downhole pump at an extremely low frequency, and its significant variation could be captured by the surface load sensor. A controlled valve is installed between the chamber of the pump and the wellbore. The valve opening regulates the pressure in the pump chamber, leading to the generation of the controlled loading waves. The field tests are further carried out and prove the effective coding between the downhole and surface with an acceptable delay (~0.154 seconds for a well with a depth of 1000 m). For the loading wave transmission on the sucker-rod string system, the finite element method is used to solve the theoretical model considering the real circumstances, such as the coupling damping, centering device friction, and stuffing box friction. The impacts of operating parameters of the lifting system, wellbore conditions, and modulation of excitation signal on the communication process are systematically discussed. The transmission evaluation standard, applicable conditions, coding tactic, and potential engineering values are presented for the downhole communication system.

Air gap membrane distillation unit operated by thermoelectric module

Membrane Distillation (MD) is a promising and evolving technology with substantial potential for efficient freshwater production. However, most of the traditional MD systems typically incorporate several components, including a coolant chamber, coolant stream, coolant pump, chiller, and coolant lines. Eliminating these key components offers numerous benefits to MD systems. Therefore, this work presents an experimental investigation of a novel hybrid air gap membrane distillation (AGMD) unit coupled with thermoelectric modules (TEMs). The thermoelectric module acts as a heat pump by simultaneously providing both the heating and the cooling demands of the air gap membrane distillation unit. In the TEM-AGMD prototype, the hot surface of the TEM is deployed to heat the feed stream to be treated, while the cold side of the TEM is in close contact with the AGMD condensation plate, thereby eliminating the need for the cooling stream, coolant line, coolant pump, chiller, and coolant chamber. Thus, the investigated system exhibited fewer components and needed no pumping power for the cooling stream, resulting in a compact and an energy efficient membrane distillation (MD) system. Results from the experiment indicate that optimal system performance can be achieved by increasing the number of thermoelectric modules, implementing multi-stage membrane distillation, and intensifying the circulating feed flowrate. Furthermore, operating the thermoelectric modules at high power input boosts unit productivity but worsens the unit's specific energy consumption. Moreover, the proposed TEM-AGMD unit can achieve a minimal specific energy consumption of 962 kWh/m3. The proposed prototype boasts an easy design that enables outstanding water desalination with exceptional salt rejection and minimal power consumption. The combination of thermoelectric module with membrane distillation, capitalizing on recent advancements in MD technology, holds great promise for developing a hybrid system for decentralized water treatment and desalination.

Simulation Analysis and Experiment of Piezoelectric Pump with Tapered Cross-Section Vibrator

In order to meet the requirements of microfluidic transport in the fields of medical, health, and microelectromechanical integration, a valve-less piezoelectric pump with a tapered cross-sectional vibrator was designed according to the bionic principles of fish swimming. Through theoretical analysis, the pattern of fluid flow in the pump chamber caused by the vibration of the piezoelectric vibrator was derived. The flow field of the piezoelectric pump was analyzed through simulation based on multiple physical fields coupling using the software of COMSOL Multiphysics (version 6.1). The velocity field distribution and its change law were obtained, and the fluid disturbance and instantaneous motion suppression phenomena were acquired as well. Based on the analysis of flow field streamline, the rule of generating vortexes was found. Thus, the driving mechanism of the vibrator with the tapered cross-section, which was consistent with the swimming principle of a fish tail, was verified. A prototype pump was made, and the pump performance was tested. The experimental data showed that the tested flow rate changed in the same trend as the simulated flow rate. When the driving voltage was 150 V and the driving frequency was 588 Hz, the pump achieved a maximum output flow rate of 367.7 mL/min. These results indicated that the piezoelectric pump with the tapered cross-sectional vibrator has great potential of fluid transportation.

Quantitative plasma proteomic analysis in children after superior cavopulmonary anastomosis with pulmonary arteriovenous malformations.

Approximately 1000 children are born every year in the United States with one effective cardiac pumping chamber, or single ventricle heart disease. One of the early causes of mortality in this population is pulmonary arteriovenous malformations (PAVMs), which allow blood to bypass gas exchange in the lungs. PAVMs most frequently occur in children after superior cavopulmonary anastomosis (SCPA), a procedure that redirects venous blood from the upper body to the lungs. Because plasma proteins are in part responsible for directing angiogenesis, we hypothesized that differential protein concentrations would be observed in superior caval blood among children after SCPA according to PAVM status. We performed quantitative plasma proteomics from 11 children with PAVMs and in seven children without PAVMs; an additional 11 children with Fontan circulation were included as a reference. Among children with SCPA, there were no significant differences in the plasma proteomes for those with and without PAVMs. When comparing children with Fontan circulation to those with SCPA and PAVMs, 18 proteins exhibited differential expression (10 downregulated and eight upregulated) in superior caval plasma. These results suggest that factors other than, or in addition to, plasma proteins may be responsible for single ventricle patients' susceptibility to PAVMs after SCPA. IMPACT: What is the key message of your article? We did not identify significant differences in plasma proteins when comparing those children with and without pulmonary arteriovenous malformations (PAVMs) after superior cavopulmonary anastomosis (SCPA). What does it add to the existing literature? The etiology of PAVMs in this population is likely due to factors other than, or in addition to, differences in plasma proteins. What is the impact? Further studies are needed to identify causes of PAVMs among children after SCPA.

Effects of particle size and reciprocating frequency of the plunger on performance and flow characteristics of a diaphragm pump

ABSTRACT The present study aims to reveal characteristics of the diaphragm pump applied in transporting the mixture of liquid and solid particles. The computational fluid dynamics (CFD) technique was used in combination with the six degree of freedom (SDOF) method to simulate the solid-liquid two-phase flow in the diaphragm pump. The zero-gap overlapping grid technique was employed to treat unsteady gap flows near the two valves. Effects of particle size and the reciprocating frequency of the plunger were investigated. The results indicate that solid particles pass smoothly through the diaphragm pump. When particle size increases from 2.0 mm to 3.0 mm, the solid volume fraction (SVF) in the pump chamber increases. When the reciprocating frequency of the plunger increases from 150 to 250 cycles per minute, the SVF increases and then decreases. When the reciprocating frequency of the plunger increases, the performance of the diaphragm pump declines, whereas the distribution of particles in the pump chamber is gradually uniformized due to the disturbance of the reversed flow from the pump outlet.

A piezoelectric pump with composite chamber: using bluff body to improve its anti-clogging ability

Piezoelectric pumps are widely used in biomedicine, chip cooling, fuel cells and so on. However, existing valve-based piezoelectric pumps suffer from the problem of easy clogging. In order to solve the problem, a piezoelectric pump with composite chamber (PPCC) is proposed. The composite chamber, consisting of drive chamber and flow chamber, which provides the PPCC with excellent output performance by amplifying the compression ratio. Meanwhile, a bluff body is set in the drive chamber, and the vortex flow around the bluff body is able to adsorb air bubbles and other impurities, preventing impurities from entering the drive chamber, the bluff body provides the PPCC with strong anti-clogging ability. Multi-physics field simulation is established, which verifies the PPCC is feasible. The fluid inside the pump chamber is simulated, and it is concluded that the 90-arc bluff body is optimal, favoring the formation of high-speed vortices. Furthermore, a prototype is fabricated and experimentally investigated. The experimental results show that the PPCC has excellent performance in pumping liquid and gas. At 300Vpp, the PPCC delivered a maximum flow rate of 235.9 ml min−1 for air and 24.07 ml min−1 for water. The anti-clogging ability of PPCC is verified through bubble resistance experiments, which demonstrates the composite chamber and bluff body effectively prevent foreign impurities from entering the drive chamber. The PPCC provides a new approach to microfluidic pumping devices.

Full time-dependent SOLPS-ITER simulation of the SPARC tokamak: actuator design for particle and divertor condition control *

This paper presents the application of full time-dependent SOLPS-ITER simulations for actuator design in the SPARC tokamak. This study employs both the EIRENE module, a neutral solver, and the B2.5 plasma module in a time-dependent mode. This is in contrast to most SOLPS simulations, which focus on steady-state solutions, where the neutral distribution is evolved without any time limit or for a time step of 1 ⋅10−3 second, which is several orders of magnitude larger than the fluid plasma time step. The time-dependent EIRENE was tested with a fixed B2.5 background and compared with a simple conductance based model in a simplified pump chamber geometry. This comparison aimed to verify the reliability of the neutral relaxation timescale derived from the time-dependent EIRENE. Subsequently, a full time-dependent simulation was performed in a realistic geometry, with the Monte-Carlo neutral time step synchronized with the plasma fluid time step. The numerical setup of the code, including relative time steps and the size of the census data used to store Monte-Carlo particle information is considered. The full-time dependent simulations are then applied to inform the design of the SPARC louver structure, which affects divertor plasma parameters by regulating the neutral conductance from the divertor to the pump. The response of the plasma and neutral parameters was captured on a timescale that enables the design of the actuator to consider time-dependent control capability. It was found that changing the louver opacity has an equivalent effect as varying the gas throughput via puff actuation. Therefore, equivalent divertor plasma conditions can be obtained from both actuators, while the neutral pressure distribution in the pump and divertor differs for each actuator.

Survival and reverse progression outcome of fetal aortic valvuloplasty and extra-cardiac conduit or lateral tunnel Fontan procedure in evolving and evolved hypoplastic left heart syndrome: a systematic review and meta-analysis

Background: Hypoplastic left heart syndrome (HLHS) is a severe congenital heart defect characterized by the underdevelopment of the left-sided heart structures, necessitating staged univentricular palliation to repurpose the right ventricle as the systemic pumping chamber. While the Fontan procedure offers a well-established method to manage single-ventricle physiology and improve survival, the potential of fetal aortic valvuloplasty (FAV) to prevent the progression of critical aortic stenosis to HLHS and achieve biventricular circulation postnatally remains significant. However, the long-term outcomes of both interventions are still uncertain. Therefore this study aims to evaluate the survival and reverse progression outcome of fetal aortic valvuloplasty and extra-cardiac conduit or lateral tunnel Fontan procedure in evolving and evolved hypoplastic left heart syndrome Methods: The literature search was conducted using PubMed, ScienceDirect, and Google Scholar databases up to May 2024. The analyses in this study were performed using R statistical software v.3.3. Results: This analysis reviewed 25 prospective and retrospective cohort studies discussing the outcomes of the FAV procedure in evolving HLHS fetuses and the Fontan procedure in pediatric HLHS patients. Among evolving HLHS fetuses, the FAV procedure had a mortality rate of 0.18 (95% CI 0.07-0.29) and a procedural success rate of 0.81 (95% CI 0.78-0.85). In pediatric patients with evolved HLHS undergoing the Fontan procedure, the mortality rate was 0.13 (95% CI 0.00-0.25), and the procedural success rate was 0.93 (95% CI 0.85-1.00). Conclusion: The Fontan procedure has shown better results than FAV, likely due to interstage procedural interventions and more established techniques for reducing morbidity and mortality in HLHS patients.

Numerical investigation of flow characteristics in the front and rear chambers of centrifugal pump and pump as turbine

To investigate the flow characteristics in front chamber and rear chamber in pump mode and pump as turbine mode, a 3D computational model of a centrifugal pump was established, including the front and rear chamber. Based on Realizable k-ε turbulence model, numerical calculations of incompressible flow were carried out for internal viscous flow in two operating modes. Further analysis was conducted on the flow stability and hydraulic losses under two modes using energy gradient theory and entropy production theory. The numerical simulation results are within reasonable error compared to the experimental results in pump operation mode, which ensures the reliability of the numerical calculation method. The results indicate that the volumetric efficiency in both two modes is on an upward trend with increasing flow, but the volumetric efficiency of the pump mode is more significantly affected by changes in flow; the distribution patterns of dimensionless circumferential velocity and dimensionless radial velocity in the front and rear chambers under two operating modes are similar, but the distribution pattern of dimensionless radial velocity in the front chamber in turbine mode is significantly different from other operating conditions; flow instability is most likely to occur at the outlet of impeller, and the energy loss in clearance of wear-rings is greater than that in the pump chamber.

Numerical Calculation and Experimental Study of the Axial Force of Aero Fuel Centrifugal Pumps

Axial force is one of the important factors affecting the life and reliability of centrifugal pumps. Based on the SST turbulence model, the unsteady internal flow field of an aero fuel centrifugal pump under various working conditions was analyzed by using the finite volume method and the axial force of the impeller component was predicted. The position servo force measuring system was used to measure the axial force of the fuel centrifugal pump and the theoretical formula of axial force was modified according to the numerical results and experimental values. The study shows that the pressure distribution of the front and rear pump chambers presented uneven circumferential distribution under the influence of dynamic and static interference through numerical simulation. The simulated head number is basically consistent with the test result and the maximum error of the axial force value obtained by the numerical calculation and the experimental value was 9.7% under different speeds, which verified the accuracy of the numerical simulation. Furthermore, the modified formula can accurately calculate the axial force of the fuel centrifugal pump with an error of less than 9.88%. The results of the study provide a theoretical basis for the calculation and balance of axial force in an aero aero fuel centrifugal pump.

Study on performance and structure optimization of self-priming pump based on response surface method

ABSTRACT This paper aims to improve the performance of a self-priming pump by optimizing blade geometry parameters, with the head and efficiency as the targeted objectives. Based on the Response Surface Methodology (RSM), the Computational Fluid Dynamics (CFD) were conducted to investigate the pressure distribution characteristics inside the pump chamber and the variations in pump performance parameters. By analyzing the internal pressure field of the pump, it is concluded that adjusting the blade curvature radius and the outlet angle can change the area and uniformity of the low-pressure zones within the fluid to improve the pump performance. The results show that the fitted regression equations indicate that the blade curvature radius and the blade outlet angle have a significant impact on pump performance, while the blade inlet angle has a relatively minor effect. When the outlet angle β 2 = 60 ∘ , the change of the inlet angle β 1 and the curvature radius R has basically no impact on the efficiency. The self-priming pump achieves its optimum performance when β 1 = 50.8 ∘ , β 2 = 52 ∘ and R = 84.9 mm. Compared to the original model, the optimized model’s head increases by 7.12%, H = 34.12 m; and the efficiency improves by 3.40%, η = 63.8.

Design and Sensitivity Analysis of Mechanically Actuated Digital Radial Piston Pumps

One major challenge in fluid power is the improvement and optimization of the efficiency of mobile hydraulic systems. Conventional fluid power systems often exhibit relatively low overall efficiencies caused by inefficiencies in the various components, such as a prime mover, variable displacement pump, valves, fittings, hoses, and actuators. While each component contributes to the losses in the overall system, the pump converts the mechanical shaft energy from the prime mover to energy transmitted hydraulically and is one of the most crucial components impacting overall system efficiency. Using on/off technologies, new pump architectures have enabled the opportunity to increase the efficiency over conventional designs using positive sealing valves in place of conventional port plate designs. This work proposes, investigates, and assesses the development and optimization of a digital variable displacement pump using a novel cam actuation technique on radial piston pumps. The novelty of this work is the development and parameter optimization of a mechanically actuated digital radial piston pump that can achieve high efficiencies from minimum to maximum displacement compared to common conventional variable displacement pump technologies. In this study, a sensitivity analysis is conducted to study the parameters of the system to optimize the pump. The parameters assessed in this study include: the valve bore size, cam transition and compression angles, piston diameter, and dead volume in the pumping chamber. The simulation results show that after optimizing the parameters of the system, the pump in design could reach a maximum efficiency of approximately 93% and was capable of upholding efficiencies above 80% between 30–100% displacement.

Thermal and fluid aspects of dual piezoelectric jet pump of double chambers

The rapid development of electronics has led to a significant reduction in the size of electronic devices, while increasing their power consumption. This has resulted in the need for small-scale thermal management solutions. Piezoelectric pump is one of the efficient devices for local thermal management. This paper presents a novel configuration of a piezoelectric pump, which separates the pump chamber with a rigid wall to create two independent pulsating flows. This configuration aims to reduce eddies within each chamber. Furthermore, the proposed design incorporates two pairs of open-sided channels to guide the pulsating flow towards the hot target. The electrostatics physic of the piezoelectric patches along with energy and momentum equations in three dimensions are manipulating mathematically and solved numerically using the finite element method (FEM) and the Arbitrary Lagrangian-Eulerian (ALE) technique. The implicit Large Eddy Simulation (iLES) turbulence model is adopted for this purpose. Several parameters, including frequency, voltage, and the radius of the piezoelectric patch are investigated to better understanding their influence on both the zero-net volumetric flow rate and the heat transfer process. The findings indicate that by separating the pump chamber, it becomes feasible to obtain a 3D solution with the iLES using a reasonable mesh size. Nusselt number increases with all the examined parameters, where it enhances by 42.48 % at V = 100 Volt when the pump is switched on compared to natural convection mode. The peak-peak volumetric flowrates rises by 50 % and 350 % when the applied voltage is raised from 50 to 100 Volts and the frequency is raised from 20 to 50.50 kHz, respectively.

The influence of ring clearance on the performance of a double-suction centrifugal pump

Due to the complex structure of a double-suction pump's suction chamber, the flow in the pump's cavity is often ignored in numerical simulations because of difficulties in structured hexahedral meshing. However, the wear ring clearance interlinking the pump chamber leads the fluid at the impeller inlet directly to the impeller area. This significantly impacts the pump's internal flow field, so the influence of the clearance on the internal flow of a double-suction pump cannot be ignored. This paper develops four three-dimensional double-suction pump models with different wear ring clearances to investigate their influence on pump performance, and structured hexahedral meshes were used for all the computational domains. The clearances varied from 0.2 to 0.5 mm in 0.1 mm increments. The influences of the clearance on the energy loss, external characteristics, and internal flow field distribution of the pump were simulated via a verified computational fluid dynamics method. The results show that the wear ring leakage decreases with the flow rate and increases with wear ring clearance. The increase in backflow leads to an internal flow disorder inside the impeller, resulting in a decreased head and efficiency. Energy loss is mainly caused by increasing the turbulence entropy production with an increasing wear ring clearance. Also, the low-pressure region in the pump cavity expands to the volute with increasing clearance, and the impeller outlet pressure decreases. This study's research on wear ring clearance provides a reference for the design and application of double-suction centrifugal pumps.