Hydraulic Performance Tests Research Articles

The simulation and analysis of the spraying status of large sprinkler machines loaded with atomizing micro-sprinklers

Due to the typically high flow rate of nozzles on large sprinkler machines, direct use for pesticide application can lead to pesticide waste and non-point source pollution. To fulfill the multifunctional needs of large sprinkler machines for irrigation, fertilization, and pesticide application, this study installed atomizing micro-sprinklers on the machines to enable their pesticide application capabilities. Based on the spraying patterns of the atomizing micro-sprinklers, three types were selected for this study: hollow cone, solid cone, and fan-shaped micro-sprinklers. Three working pressure levels were set at 0.2 MPa, 0.3 MPa, and 0.5 MPa, with the height of the micro-sprinklers above the ground set at three levels: 0.8 m, 1.2 m, and 1.5 m. A completely randomized design was used for the experiment, which included hydraulic performance tests and software simulation. The results indicated that the spray volume of the hollow cone, solid cone, and fan-shaped atomizing micro-sprinklers approximately presented a hollow conical, solid conical, and normal distribution, respectively. The spray intensity (average and maximum values) of the atomizing micro-sprinklers increased with the increase in pressure, while the median showed an initial increase followed by a decrease as pressure increased. Under the same pressure conditions, the spray intensity of the different atomizing micro-sprinklers decreased with the increase in height above the ground, while the spray width increased with height. By comparing the spraying characteristics of micro-sprinklers with various patterns, large sprinkler machines can select atomizing micro-sprinklers in different spraying statuses according to actual conditions and determine the optimal height of the atomizing micro-sprinklers above the ground to achieve efficient and uniform pesticide application effects. This reduces the evaporation and drift loss of liquid medicine. The research findings provide a scientific basis for achieving the pesticide application function of large sprinkler machines and expanding their usage capabilities.

Effect of blade length on unsteady cavitation characteristics of hydrodynamic torque converter

Hydrodynamic torque converters (HTC), as power transmission component for high-power machinery, achieve flexible and energy saving transmission by circulating viscous oil through multi-stage impellers, involving cavitation at high flow speeds. To achieve cavitation suppression and performance enhancement, this study analyzed the mechanism of HTC blade length on cavitation effects. The Computational Fluid Dynamics (CFD) model of cavitation in the internal flow field of HTCs with different blade length were established, a hydraulic performance and flow-induced vibration test system was set up, and experimental prototypes with different blade lengths were designed and manufactured. The macroscopic and microscopic transient cavitation characteristics of different blade length were studied. The results show that shortening the length of pump and turbine blades has a significant suppression effect on cavitation. Due to changes in the impeller outlet flow field and circulation flow, the cavitation attachment range has changed significantly. Additionally, the significant impact of blade length on the flow-induced vibration influent the evolution characteristics of transient cavitation. Shorter blades reduce the amplitude of pressure oscillations, improving the attachment stability of cavitation. This study has important implications for improving the performance of HTCs and reducing the occurrence of cavitation.

Optimization of Magnetic Pump Impeller Based on Blade Load Curve and Internal Flow Study

Compared to traditional centrifugal pumps, magnetic pumps are widely used in industries such as chemical, pharmaceutical, and petroleum due to their characteristics of leakage-free operation and the ability to transport toxic and corrosive fluids. However, the efficiency of magnetic pumps is relatively low. Improving the efficiency of pumps helps to reduce energy loss and lower industrial costs. In this study, a magnetic pump was chosen as the research subject. The study aims to improve the efficiency and stability of the magnetic pump by optimizing the impeller blades based on the load curve. A combined approach of a numerical simulation and experimental verification was used to investigate the impact of the anterior loading point (AL), posterior loading point (PL), and slope (SL) in the blade loading curve on the pump’s performance. The slope, which had the most significant impact on pump performance, was selected as the dependent variable to analyze the internal pressure pulsation and main shaft radial force of the magnetic pump. The research found that the hydraulic performance test results of the magnetic pump were in good agreement with the simulation results. When efficiency is used as the optimization objective, the anterior loading point should be moved as far back as possible, and the posterior loading point should be moved as far forward as possible. Through the study of internal pressure fluctuations and radial forces within the pump, the radial force distribution is sequentially as follows: the anterior loading method, posterior loading method, and middle loading method at a rated flow rate. The maximum pressure pulsation amplitude was near the volute casing diffuser area. Compared to the original pump, the optimized magnetic pump showed a 5.05% improvement in hydraulic efficiency under the rated conditions. This research contributes to enhancing the performance and efficiency of magnetic pumps, making them more suitable for various industrial applications.

Analysis of energy loss in the helical hedge flow channel of fruit tree root emitter

This paper proposes the design of a helical hedge flow channel with a high energy loss, which shows promising potential for application in fruit tree root emitters. The aim is to investigate the relationship between the energy loss form in the channel and its influencing factors. The hydraulic performance testing method is employed to analyze the factors that affect energy loss. The main influencing factors are determined using the response surface methodology (RSM) for experimental design. Based on the obtained experimental results, the energy loss form and influencing factors are analyzed, and a prediction model for the energy loss coefficient (ξ) is established. The results indicate that the ξ exhibits a decreasing trend with an increase in the diversion angle (α), a trend of first increasing and then decreasing with an increase in the channel width (b), and an increasing trend with an increase in the number of channel units (n). The effects of the straight section length (l1), convergence section length (l2), and bend radius (r) on the ξ can be neglected. The ranking of the geometric parameters' influence on the ξ is as follows: n > b > α > l1 > r > l2. The experimental results reveal that the ξ ranges from 19.2 to 234.3. Furthermore, the head loss along the flow channel constitutes merely 0.06–0.47% of the local head loss, The main form of energy loss in the spiral counter flow channel is local head loss. There is a significant linear relationship between α, b, n and the ξ, The established prediction model (R2 = 0.9691) can accurately predict the ξ of the channel.

Large-Scale Hydraulic Performance Testing of a Geotextile Mechanically Stabilized Earth (MSE) Wall Constructed with Recycled Concrete Aggregate Backfill

Abstract Constructing geosynthetic mechanically stabilized earth walls with recycled backfill materials reduces environmental impacts and financial cost compared with their gravity wall counterparts. While a large database of column-scale tests to evaluate the hydraulic performance of recycled backfill materials exists in the literature, clogging potential under multidimensional flow conditions has not been examined. A large-scale reinforced soil wall and a complementary column test constructed with recycled concrete aggregate (RCA) and closely-spaced woven geotextile reinforcement were tested to examine chemical and physical clogging under wetting-drying cycles. Internal moisture migration and the evolving chemical signature of leachate were measured. Geotextile samples were exhumed after the tests and analyzed to evaluate chemical (tufa formation) and physical (fines migration) clogging. The complementary multidimensional and column experiments afford direct comparison of outflow chemistry and effects on geotextile permittivity. Geotextiles in the large-scale wall and column tests did not show any evidence of chemical or physical clogging and no evidence of positive pore pressures was detected. Outflow leachate from the wall test had higher total dissolved solids values and higher concentrations of Ca and SO4 in comparison to the column test. The pH of leachate from the column test is initially lower than from the wall, but results become similar (pH ∼12) at test completion. Leachate from both tests is supersaturated with tufa minerals. Differences in leachate characteristics of the two tests can be attributed to the initial moisture content of the backfill, larger quantity of RCA material in the large-scale wall, and the multidimensional flow characteristics of the large-scale wall. Results validate previous observations from column tests in terms of moisture retention and chemical response when flow conditions are multidimensional. Maintaining a free-draining backfill under conditions that could promote clogging (closely-spaced woven geotextile reinforcement layers) gives further confidence in using RCA as backfill under these conditions.

Numerical Simulations of Flow-Induced Deflections in MITR LEU Fuel Plate Due to Channel Size Disparity

The hydromechanical stability of the fuel plates in parallel coolant channels of a Materials Testing Reactor (MTR) fuel element design is of great importance to the safety of research and test reactors. Previous analytical, experimental, and numerical efforts focused on parallel channels with the same or similar size; also, in the prior numerical simulations, the fuel plate was often assumed to be perfectly flat. This work presents the results of a fluid-structure interaction simulation performed to evaluate the flow-induced deflections of the fuel plates in the low-enriched uranium (LEU, <20 wt% 235U) fuel element design for the conversion (from highly enriched uranium) of the Massachusetts Institute of Technology Reactor (MITR-II, also referred to as MITR). Various manufacturing and assembly tolerances of the MITR LEU elements are considered in the analysis, and the effects of channel size disparity, nonideal plate shape, and flow rate uncertainty are investigated. Results show that, for all cases analyzed, the deflection occurs toward the larger channel, and the change in any channel stripe remains small (less than 0.021 mm) compared to fabrication tolerances. In addition to simulation work, a hydraulic performance test of the MITR LEU fuel element is currently planned to support conversion to the use of LEU fuel.

P18: Improving Hydraulic Performance of the Left Atrial Assist Device Using Computational Fluid Dynamics

Purpose of Study: The purpose of this study was to refine the initial design of a new left atrial assist device (LAAD) using the results from computational fluid dynamics analyses (CFD). The CFD results would help guide design changes that could improve the hydraulic performance and flow patterns within the LAAD. The LAAD is a novel continuous-flow pump, implanted in the mitral plane, designed to treat patients with heart failure with preserved ejection fraction. Methods: Four different LAAD designs were evaluated. The key differences among the designs included changes to the shape and dimensions of the primary impeller blades, and the number, size, and curvature of the diffuser vanes. Steady state, frozen-rotor CFD simulations were run at flow rates and rotor speeds spanning the LAAD’s intended range of use. Of the four designs studied, the first and final designs were prototyped and underwent in vitro hydraulic performance testing. The in vitro studies were conducted by connecting a prototype LAAD to a mock circulatory loop system designed to simulate various levels of diastolic heart failure. Static pressure measurements, taken upstream, downstream, and at two other locations within the pump, were compared with CFD-predicted pressures to validate the CFD modeling approach and results. Results: The CFD-predicted static pressures agreed within 12% for design #1 and 10% for design #4 over a wide range of flow rate/rotor speed conditions providing confidence in the CFD modeling results. Regions of flow separation downstream of the impeller blade tips and the diffuser vanes were reduced for each design iteration. Increasing the impeller blade diameter, provided increased pump pressure rise at the expense of significantly higher torque and power requirements. A comparison of the hydraulic performance for the four designs, as shown in Figure 1, reveals that design #4 was able to provide the same pump pressure rise as design #1 at 3,800 vs. 4,400 rpm. Conclusions: Guided by the insight gained from each design iteration, the fourth design incorporated impeller blades with an improved alignment with the incoming flow and wider, more curved diffuser vanes that aligned with the approaching flow from the volute. These changes reduced flow separation within the impeller and diffuser regions which significantly improved the LAAD’s hydraulic performance and internal flow patterns. In vitro testing of this fourth generation LAAD design confirmed the predicted improvement in hydraulic performance.Figure 1. Comparison of the hydraulic performance for the four LAAD designs at a flow rate of 4.5 L/min and varying rotor speeds.

Modelling the hydraulic performance of open graded asphalt using the discrete element method and computational fluid dynamics

Porous asphalt (PA) pavements are used as an alternative for non-permeable pavements to tackle hydroplaning issues and reduce splash and spray. The key aspect of designing a PA pavement is its hydraulic performance. This study introduces a novel numerical approach combining the discrete element method (DEM) and computational fluid dynamics (CFD) to model the hydraulic performance of PA. Different from the traditional methods of scanning the internal asphalt matrix using X-rays, this study uses a photogrammetry-analysis technique to convert the aggregate structure into a DEM. DEM modelling was then used to create a random aggregate structure with different sizes to simulate the asphalt samples for testing. The information about the sample structure was transferred to CFD for the hydraulic performance simulation. The effects of the air voids content, air voids distribution, and sample structure on the vertical and horizontal hydraulic performance were investigated. The results showed that the proposed approach is capable of producing virtual test samples resembling the laboratory PA sample structure for hydraulic performance tests. It was found that the outlet flow rate was mainly affected by the total air voids content of the sample. Higher content and evenly distributed air voids over the depth of the PA samples led to better hydraulic conductivity. Samples created and tested using DEM-CFD methodology could also effectively predict the flow rate at the outlet and demonstrate the flow movement between connected pores inside the sample structure.

Impact of Elastic Diaphragm Hardness and Structural Parameters on the Hydraulic Performance of Automatic Flushing Valve

Automatic flushing valve (AFV) can improve the anti-clogging ability of the drip fertigation system. The minimum inlet pressure (Hamin) required for automatic closing and the maximum flushing duration (FDmax) are two important performance indexes of AFV. The existing AFV products have the problem of larger Hamin and smaller FDmax, which result higher investment and operating cost, and poor flushing efficiency. Based on the mechanical analysis of the AFV elastic diaphragm and the derivation of the FD, elastic diaphragm hardness (E), ascending channel offset distance (D), and drain hole width (W) were selected as the experimental factors, and nine AFVs were designed by L9(33) orthogonal test method to investigate the influence of elastic diaphragm hardness and structural parameters on the hydraulic performance of AFVs. The hydraulic performance test results showed that the Hamin of the nine AFVs ranged from 0.026 to 0.082 MPa and FDmax ranged from 36.3 to 95.7 s. Hamin was positively correlated with E and D and negatively correlated with W. FDmax was negatively correlated with E and W and tended to increase and then decrease with D. All elastic diaphragm hardness and structural parameters had a significant effect on Hamin, and E and W had a significant effect on FDmax. Based on the range analysis, two new combinations of AFV elastic diaphragm hardness and structural parameters with minimum Hamin (E = 40 HA, D = 0 mm, W = 2 mm) and maximum FDmax (E = 40 HA, D = 2 mm, W = 1.68 mm) were determined, and the corresponding Hamin was 0.022 MPa, 63.3% lower than that of the existing product, and FDmax was 116.4 s, 71.2% higher than that of the existing product. In this study, two ternary nonlinear mathematical regression models of Hamin and FDmax with elastic diaphragm hardness and structural parameters was constructed. The simulation accuracy of the models is good and can be used to quickly predict the optimal combination of AFV parameters to satisfy the actual engineering-required Hamin and FDmax.

Hydraulic performance and flow resistance tests of various hydraulic parts for optimal design of a reactor coolant pump for a small modular reactor

Hydraulic performance and flow resistance tests were performed to confirm the main parameters of the hydraulic instrumentation that can affect the pump performance of the reactor coolant pump. The flow resistance test offers important experimental data, which are necessary to predict the behavior of the primary coolant when the circulation of the reactor coolant pump is stopped. Moreover, the shape of the hydraulic section of the pump, which was considered in the test, was prepared to compare the mixed-flow- and axial-flow-type models, the difference in the number of blades of the impeller and diffuser, the difference in the shape of the impeller blade and its thickness, and the effect of coating at the suction bell. Additionally, five models of the hydraulic part were manufactured for the experiments. In this study, the differences in performance owing to the design factors were confirmed through the experimental results.

Geotechnical Characterization of Biomass Ashes for Soil Reinforcement and Liner Material

Biomass ashes (BA) have been intensively studied as amendments for soil in earthworks. This paper aimed to geotechnically characterize BA from pines and olive trees compared to the soil from Castelo Branco, Portugal. Namely, granulometry, specific gravity, Atterberg limits and optimal compaction values were obtained and analyzed in order to valorize the residue incorporated into soils. This work is part of broader efforts to develop an alternative material that can be used in hydraulic barriers as liners and for soil reinforcement. Thus, BA can contribute to reductions in weight and plasticity, and filling properties. Further studies are needed, particularly mechanical and hydraulic performance tests.&#x0D; Keywords: biomass ashes, geotechnical and mechanical properties, residue valorization, soil reinforcement, liner material

Elimination of Clogging of a Biogas Slurry Drip Irrigation System Using the Optimal Acid and Chlorine Addition Mode

As an emerging contaminant, the clogging substances of emitters in biogas slurry drip irrigation systems affect the efficient return and utilization of biogas slurry to the field to a great extent. This can be prevented using acid and chlorination as engineering measures. Through a hydraulic performance test and sampling detection and analysis, under the same acid addition conditions (pH = 5.5–6.0), three chlorine addition concentrations (0, 1–3, and 4–9 mg/L) and four chlorine addition cycles (6, 10, 14, and 20 days) were tested, aimed to clarify the influence of acid and chlorine addition parameters (chlorine adding cycle, chlorine adding concentration, etc.) on the anti-clogging performance of emitters in biogas slurry drip irrigation system. The results showed that compared with no acid and chlorination treatment (CK), only acid and a reasonable combination of acid and chlorination can significantly reduce the probability of serious and complete clogging of biogas slurry drip irrigation emitters, and they can stabilize the relative average flow of emitters by more than 75%. The measures of adding acid and chlorine change the distribution characteristics of clogging substances at the front and rear of the drip irrigation belt. Furthermore, they promote the migration of clogging substances to the rear of the drip irrigation belt, facilitating the clogging of emitters located thereat. The measures of acid addition and sequential addition of acid and chlorine significantly inhibit the growth of an extracellular polymer in the emitter, and the effect of inhibiting the increase in extracellular polymer concentrations is relatively poor when the acid addition period is excessively long or short. There exists a negative correlation between the extracellular polymer content in the emitter and the change in the emitter flow. Based on the obtained results, to ensure excellent anti-clogging performance of biogas slurry drip irrigation systems, for acid-only treatment measures, the acid dosing cycle is recommended to be 10 days. When acid and chlorination measures are implemented sequentially, the acid chlorination cycle is recommended to be 14 and 10 days when the chlorine concentration is 1–3 and 4–9 mg/L, respectively. This study has important scientific significance and practical value for the establishment of long-term operation management and protection technologies of large-scale biogas slurry drip irrigation systems.

Characterization of labyrinth emitter-clogging substances in biogas slurry drip irrigation systems

Drip irrigation is important for efficiently returning biogas slurry to fields. Elucidating the characteristics and components of clogging substances produced by labyrinth emitters in biogas slurry drip irrigation systems will help to develop various clogging substance-remediation strategies. However, previous studies were unable to characterize the clogging substances in emitters. Thus, we aimed to characterize and quantify the substances clogging emitters in a biogas slurry drip irrigation system and determine the micromorphology and dominance of microbial communities. Here, emitter discharge changes and the micromorphologies, phase compositions, and biological communities of clogging substances were studied via hydraulic performance tests, scanning electron microscopy–energy depressive spectra (SEM-EDS), and high-throughput sequencing. The degree of emitter-clogging increased over time (first quickly, then slowly) and was deeper at the end of the drip irrigation tape than at the head. The clogging substances were viscous agglomerations primarily comprising 0.3–1.5-μm particles. Their formation was affected by settlement with gravity, water pressure adhesion, and mobile biological adhesion. The dominant microbial communities in the clogging substances included Firmicutes (29.7%) and Proteobacteria (19%); the emitter-clogging substances primarily comprised water (85%) and composite dry matter. The water, dry matter, and extracellular polymer substance (EPS) weights in the clogging substances increased over time, but their relative proportions remained stable. In the composite dry matter, typical physical (organic carbon, Al2O3, and SiO2), chemical (CaCO3 and MgCO3), and biological (EPS) clogging substances accounted for >50, 9, and 5.62% of the total dry matter mass, respectively. This study provides a good foundation and reference idea and will be very helpful to propose targeted solutions for solving the clogging of biogas slurry drip irrigation system.

Research on Wear Characteristics and Experiment on Internal Through-Passage Components for a New Type of Deep-Sea Mining Pump

The conveyor electric pump for deep-sea mining is a key piece of equipment in deep-sea mineral transportation systems, as its flow capacity and wear resistance affect the reliability of the entire system. In this study, aimed at solving problems such as mining pumps being prone to clogging and wear, which could lead to performance degradation, a mining pump with wide flow paths and high performance was designed, and hydraulic performance tests were conducted on the new pump. The test results obtained were in good agreement with the numerical simulation results. Based on the reliability of the performance test results, using computational fluid dynamics (CFD) methods, and taking the wear model into consideration, a wear analysis was conducted on the internal through-passage components of the pump under different solid-phase particle parameters and operating conditions, and the average wear rate on the surface of the predominant through-passage components was calculated. The results showed that the hydraulic performance of the newly designed pump met the design requirements, with different particle parameters and operating conditions causing different degrees of wear on the through-passage components. The wear test was carried out with a test pump, and the comparison between the test results and the numerical calculation results showed that the numerical calculation of the wear of the deep-sea mining pump was accurate.

Development of remote hydraulic system based on BS framework

Based on the analysis of related research at home and abroad, combined with the experimental requirements of hydraulic teaching and scientific research, this paper designs a remote teaching experiment project and content for hydraulic pump performance test based on B / s network architecture. The field experiment subsystem is designed and developed, and the field experiment measurement and control software is developed based on LabVIEW. The step responsetracking experiments in the field experiment and remote terminal experiment are compared and analyzed. The response speed and control accuracy of the remote terminal experimental system are slightly lower than that of the field experimental system, but both of the two systems can achieve good control of the controlled quantity, which can meet the needs of remote and field hydraulic experiments Using construction has an important role in promoting.

Performance Optimization of a Newly Designed Dynamic Fluidic Sprinkler

HighlightsThe results confirmed that the optimal combination of structural parameters was achieved with the factor combination of 25 mm length of the tube, 150 kPa pressure, 3 mm diameter of the tube, and 5 mm nozzle diameter.The influencing factors in decreasing order of importance were: working pressure, length of the tube, and nozzle diameter for coefficient of uniformity, and nozzle diameter working pressure and diameter of the tube for range.Droplet velocities from test 7 ranged between 0 and 6.0 m/s, while that from test 2 was slightly larger, ranging from 0 to 6.7 m/s under low-pressure conditions.ABSTRACT: To select the appropriate combination of the factors for the dynamic fluidic sprinkler, hydraulic performance tests at low pressure were conducted. The main structural parameters in this study were the length of the tube (L), pressure (H), the diameter of the tube (M), nozzle diameter (N), they are represented by factors A, B, C, and D, respectively. An orthogonal array with four factors and three levels was selected, and the direct analysis technique was used to analyze the test data. The droplets and velocities data of the sprinkler were obtained by a Thies Clima Laser Precipitation Monitor. MATLAB R20014a software was used to calculate the simulated coefficient of uniformity (CU). The results showed that the optimum values of the structural parameters were: the length of the tube (25 mm), the working pressure (150 kPa), the diameter of the tube (3 mm), and the nozzle diameter (5 mm). The factors affecting coefficient of uniformity and range, in decreasing order of importance were nozzle diameter, pressure, length of the tube, and the diameter of the tube. The highest coefficient of uniformity obtained was 91% when the length of the tube was 25 mm. Droplet sizes decreased with the increase of pressure. Droplet size ranging from 0.1 to 4 mm was obtained under test 7 with a mean droplet size of 0.38 mm. The study can give a reference to the operation for saving water in sprinkler irrigated fields. Keywords: Droplet, Dynamic fluidic sprinkler, Orthogonal test, Structural parameter, Uniformity, Velocity.

Development of Hydraulic Device Performance Test Equipment Automation Process

Development of Hydraulic Device Performance Test Equipment Automation Process

The hydraulic performance of twin-screw pump

Based on the computational fluid dynamics (CFD) and the experiment technology, this paper presents a new type of the twin-screw pump for the water-supply and studies its hydraulic performance with the hydraulic performance test. The internal flow characteristics and the hydraulic performance of the twin-screw pump are numerically simulated. The CFD results show that at different heads, the screw pressure gradually increases from the inlet end face along the axial direction of the screw to the outlet end face. The pressure distribution in the screw groove is relatively uniform, the screw clearance and the meshing area pressure are different from the screw groove pressure distribution. Under the same working condition of the head, the pressure distributions in the screw below and above the design speed are the same as the pressure distribution at the design speed, and with the range of the pressure value quite close. As the rotating speed increases furthermore, the flow rate and the volume efficiency of the pump both increase. At different rotating speeds, the velocity distributions along the axial direction of the screw are similar. A test rig is built, which consists of a closed-loop circuit, and the test results are found in good agreement with the CFD predictions. The experimental results show that the flow rate-head curves of the twin-screw pumps are similar at different rotating speeds. The research shows that the designed twin-screw pump enjoys a higher volumetric efficiency and a lower shaft power when the axial clearance is 0.08 mm-0.12 mm. When the clearance is 0.1 mm, the volumetric efficiency is the highest.

CFD-Rotordynamics Sequential Coupling Simulation Approach for the Flow-Induced Vibration of Rotor System in Centrifugal Pump

Vibration of the rotor system is closely related with the operation stability of centrifugal pump, and it is inevitably induced by the unsteady inner flow. An unsteady computational fluid dynamics model coupling with a rotordynamics model was presented, and the corresponding numerical calculation program, including a self-designed rotordynamics code, was developed on the commercial package ANSYS Workbench. The validity of the numerical calculation model was verified by a hydraulic performance and vibration test based on an industrial centrifugal pump. The hydraulic radial forces on impeller, pressure pulsation, deformation, and vibration of the main shaft under nine different flow rates were systematically investigated and explained preliminarily from the view of inner unstable flow. Results show that the blade passing frequency is the dominant frequency in the fluctuation of the above dynamical behaviors, which is closely related to the rotor–stator interaction between the impeller and volute casing. This study built the connection between internal fluid flow in the centrifugal pump and the vibration of its external rotor structure, and may provide theoretical references for the design of vibration-reducing and safety monitoring strategies design of centrifugal pumps.

Optimization of CPR1000 Charging Pump Shaft Power and Hydraulic Performance Study

Based on the analysis of CPR1000 charging pump hydraulic performance test, it is found that the large inlet area of the diversion body is the main reason for the high shaft power. Every piece of steel plate was welded to the inlet tongue respectively to improve the hydraulic performance of the charging pump. Firstly, with the help of Ansys CFX, the flow field inside the charging pump of the modified scheme was numerically simulated and compared with the measured hydraulic performance data before the scheme modification. Then the hydraulic performance of the charging pump was tested and verified. The results show that the shaft power of the charging pump is controlled below 650 kW, meeting the requirements of the evaluation test program and technical specification, and the safety and reliability of the charging pump is improved.