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  • Design and visualization testing study of high-speed gas-liquid multiphase booster pump

    DONG Dong;LI Xiaojun;YU Ruirong;XIE Gongdie;LI Xiaoduo;YE Zhangyi;Zhejiang Key Laboratory of Multiflow and Fluid Machinery,Zhejiang Sci-Tech University;Xinxiang Aviation Industry (Group) Co.,Ltd.;Ebara Great Pumps Co.,Ltd.;

    To address the performance failure of conventional centrifugal pumps under high gas content multiphase transportation conditions,a high-speed gas-liquid multiphase booster pump covering conventional centrifugal pump performance parameters was designed. Maintaining bubbly inflow and through visualization testing,its performance and internal flow characteristics under variable conditions were analyzed.The results show that the pump can transport mixed medium with inlet gas volume fraction of 55% under rated conditions;as inlet gas volume fraction increases,the pump head coefficient shows a nonlinear decreasing trend,and the inlet flow pattern gradually transitions from bubbly flow Ⅰ to bubbly flow Ⅱ,Ⅲ,Ⅳ.When the flow pattern develops to bubbly flow Ⅲ,the pump performance loss and inlet flow pattern transition delay reach their maximum;increasing rotational speed can achieve up to 6.65% maximum inlet flow pattern transition delay rate and enhance the pump's gas mixing resistance capability;small liquid flow rate helps slow down performance degradation under high inlet gas volume fraction conditions,while increasing liquid flow rate intensifies gas-liquid separation inside the pump;reducing liquid flow rate can achieve up to 7.04% maximum inlet flow pattern transition delay rate.This research provides theoretical support for the optimal design and efficient operation of gas-liquid multiphase booster pumps.

    2025 10 v.53;No.640 [Abstract][OnlineView][Download 2312K]

  • Study on control method for non-uniform pollutant concentration field based on POD

    WANG Fei;YAN Xun;LIN Chengjie;MENG Qinpeng;WANG Xin;School of Environment and Architecture,University of Shanghai for Science and Technology;School of Mechanical Engineering,Tongji University;

    To address the issue of excessive ventilation energy consumption caused by the assumption of uniform pollutant distribution in industrial ventilation methods,an intelligent ventilation control method based on flow field prediction and traversal optimization is proposed.This method can dynamically regulate the ventilation system according to the needs of target control points. First,proper orthogonal decomposition(POD) is used to reduce the dimensionality and reconstruct the pollutant concentration field,obtaining low-dimensional basis functions and their coefficients;then, basis coefficient interpolation technology is employed to predict dynamic pollutant concentration distributions under different air supply parameters;finally, a traversal optimization algorithm is adopted to search and determine the optimal combination of air supply parameters,which is verified in a two-dimensional air supply parameter space.The results show that the pollutant concentration distribution predicted by this method has a small relative error compared with numerical simulation values,and can accurately predict the concentration field;the optimization algorithm can precisely locate the optimal air supply parameters that meet the requirements,achieving an optimal control error of 0.1%;the running time of the control program in the two-dimensional parameter space is only 78 s,demonstrating the potential of this method for real-time ventilation control.The intelligent ventilation control method proposed in this study provides a new intelligent solution for industrial ventilation,with good applicability and application prospects.

    2025 10 v.53;No.640 [Abstract][OnlineView][Download 2151K]

  • Experimental study of pressure pulsation characteristics of standpipe-valve system in a circulating fluidized bed

    BA Yingdala;HE Jiao;CHEN Xiaoling;LIU Mengxi;WEI Yaodong;ZHANG Yuming;State Key Laboratory of Heavy Oil Processing,China University of Petroleum(Beijing);Faculty of Engineering,China University of Petroleum(Beijing) at Karamay;Karamay Special Equipment Safety Inspection Institute;

    To address the issue of uncertain pressure pulsation characteristics during the cyclic downward movement of particles in a standpipe-valve system and the lack of quantitative characterization,an experimental study on pressure pulsation characteristics was conducted.By varying the particle mass flow rate,the dynamic pressure of the gas-solid two-phase flow before and after the valve(at measuring points P1 and P2) was measured.Through analytical methods including dynamic pressure,static pressure,standard deviation,and power spectral density,the pressure fluctuation characteristics within the standpipe-valve system were thoroughly investigated. The results indicate that as the particle mass flow rate Gs increases from 0 to 117.72 kg/（m2·s）,significant low-frequency,high-amplitude pressure fluctuations occur in the system,primarily due to particle clustering,gas-solid interactions,and bubble disturbances.The standard deviation of the dynamic pressure at point P2 shows a linear relationship with the particle mass flow rate,suggesting that the standard deviation can be used for real-time monitoring of the particle mass flow rate in circulating fluidized beds.When the particle mass flow rate Gs=0,both points P1 and P2 on the standpipe exhibit a single dominant frequency with relatively low power spectral density.As the particle mass flow rate increases to 6.28 kg/（m2· s）,both P1 and P2 display dual-frequency characteristics,comprising a primary frequency and a secondary frequency.The power spectral density at P1 initially increases and then decreases with increasing particle mass flow rate,while at P, 2 it increases with increasing particle mass flow rate.The pressure pulsations within the standpipe are all low-frequency(<0.41 Hz) and act as the excitation force causing standpipe vibration.This study provides a theoretical basis and experimental support for the optimal design and safe operation of particle circulation systems in circulating fluidized beds.

    2025 10 v.53;No.640 [Abstract][OnlineView][Download 1877K]

  • Cause and characteristic analysis of asymmetric pressure distribution in scroll chambers of electric vehicle scroll compressors

    ZHAO Zibo;WU Jianhua;WANG Che;School of Energy and Power Engineering,Xi'an Jiaotong University;

    To investigate the causes and characteristics of asymmetric pressure distribution in scroll chambers,mathematical models for geometric analysis and thermodynamic processes were established based on asymmetric features.Dynamic pressure measurement tests inside the scroll chamber of an electric vehicle scroll compressor were conducted,validating model rationality.Under pressure ratios of 2 and 5 and rotational speeds of 3 000 r/min and 8 000 r/min,pressure variations in scroll chambers,valve rear chambers,exhaust ports,and pressure relief ports versus orbiting scroll angle were calculated.Results show that with a 50° difference in end angles between fixed and orbiting scrolls,a pressure difference of approximately 0.02 MPa exists in bilateral scroll chambers during early-mid compression. At pressure ratio 5,asymmetric pressure distributions remain similar across speeds,with maximum discharge pressure reaching 2.1 MPa at high speeds indicating severe over-compression.At 3 000 r/min,asymmetric pressure characteristics differ with increasing pressure ratios due to changes in the relative magnitude of designed internal versus operational external pressure ratios.Under low pressure ratios,implementing pressure relief structures reduces indicated power by 1.4% at 3 000 r/min but increases it by 0.65% at 8 000 r/min compared to non-relief configurations.This study provides guidance for scroll profile design and optimization.

    2025 10 v.53;No.640 [Abstract][OnlineView][Download 1810K]

  • Study on flow characteristics and energy loss mechanism of electric fan for vacuum cleaner

    LIU Wenjing;YUAN Jianping;HE Renzhi;WANG Peng;SI Qiaorui;Research Center of Fluid Machinery Engineering and Technology,Jiangsu University;Zhejiang Yili Machinery & Electric Co.Ltd.;

    In order to explore the energy conversion characteristics of the vacuum cleaner fan,the full-flow field numerical simulation of the fan flow field under different working conditions was carried out to analyze the flow characteristics. After verification by performance tests,the distribution of the local entropy production rate of the impeller was analyzed based on the entropy production theory.The results indicate that there is an obvious flow impingement at the blade inlet.At the impeller outlet,the mixing of wake and jet increases the velocity gradient and forms a jet wake structure.As the flow rate decreases,large-scale backflow occurs inside the impeller.Local entropy production is the main factor affecting the energy consumption of the fan.Under the design conditions,the proportion of local entropy production is 59.06%,and the high entropy production area is mainly concentrated at the blade inlet,the suction surface of the blade leading edge and the blade outlet trailing edge.By analyzing the distribution of secondary flow in different annular sections of the impeller,it is found that the secondary flow at the impeller inlet becomes more obvious as the flow rate increases,and the high entropy production areas mostly appear in the regions where secondary flow is generated,indicating that secondary flow is an important factor causing energy loss.

    2025 10 v.53;No.640 [Abstract][OnlineView][Download 2498K]

  • Effect of needle shape on performance of adjustable jet pump

    ZHANG Yan;CHEN Yunliang;ZHAO Hui;XIANG Weining;College of Water Resource & Hydropower,Sichuan University;

    To improve the performance of the adjustable jet pump,the end protrusion structure of the conventional needle head was changed to a streamlined structure with smooth circular arc connections,in order to reduce the disturbance of the needle to the working fluid.Numerical simulations were conducted for adjustable jet pumps with conventional needles and streamlined needles under different nozzle opening conditions to study the influence of needle shape on energy transfer efficiency and the,internal flow field.The results show that compared with the conventional needlethe streamlined needle has a smoother flow channel inside the nozzle,which can better improve the flow conditions of the needle and nozzle,thereby facilitating jet energy transfer;The overall efficiency of the adjustable jet pump in the streamlined injection needle is improved,with an increase of about 2.5% when the nozzle opening is 50.41%,and the relative head loss of the nozzle can be reduced by 5.19%.At the same time,the streamlined injection needle can improve the pressure distribution in the nozzle. Under the conditions of nozzle opening of 50.41% and flow ratio of 0.4,it ensures a minimum negative pressure calculation value of approximately-89 kPa,avoiding that excessively low pressure and cavitation occur inside the nozzle..The research results can provide references and basis for the structural design and performance improvement of adjustable jet pumps.

    2025 10 v.53;No.640 [Abstract][OnlineView][Download 2548K]

  • Study on heat transfer-flow-reaction characteristics of 3D printed catalyst supports with different structures

    ZOU Hongwei;LIANG Zhuangdian;CHEN Yongdong;HAN Bingchuan;WANG Gang;Hefei General Machinery Research Institute Co.,Ltd.;Shanghai Advanced Research Institute,Chinese Academy of Sciences;

    To address the efficiency bottlenecks in in-tube methanol reforming for hydrogen production,a design method for structured catalyst supports based on 3D printing technology was proposed.Numerical simulations of heat transfer and fluid flow were conducted at a Reynolds number(Re) of 140 to compare three channel structures:straight channels,zigzag channels,and helical channels.Taking the straight channel as the reference model,the reaction performance was thoroughly investigated,and a numerical calculation model was established(with deviations of ≤5% for methanol conversion and ≤0.6% for CO selectivity).Structural screening of the three configurations was completed via model predictions and experimental validation.Results indicate that the helical channel exhibits the highest Performance Evaluation Criterion(PEC) value of 14.7.Both methanol conversion and CO selectivity in the methanol reforming reaction increase with increasing temperature and decrease with rising volumetric flow rate. Both model predictions and subsequent screening experiments confirm that the helical channel maintains optimal performance.Specifically,experimental data show that the methanol conversion of the helical structure reaches 65.8%,which is 11.4% and 24.4% higher than that of the zigzag channel and straight channel,respectively.This study provides a theoretical basis for the design of 3D-printed catalyst supports.

    2025 10 v.53;No.640 [Abstract][OnlineView][Download 1621K]

  • The effect of gas volume fraction on the two-phase flow field and structural deformation in a progressive cavity pump

    ZHANG Xuejing;WANG Li;ZHU Guisheng;YAO Yuwang;HAN Wei;Department of Architecture and Transportation Engineering,Guilin University of Electronic Technology;Department of Energy and Power Engineering,Lanzhou University of Technology;

    To investigate the flow characteristics and multi-field coupling mechanisms inside the twin-screw pump.Based on the Eulerian-Eulerian heterogeneous flow model and the immersed boundary method,a transient simulation of the flow field in a multiphase twin-screw pump was conducted under varying gas volume fraction conditions.The variations in pump outlet flow rate,pressure,phase distribution,and rotor surface velocity were analyzed.The fluid pressure was applied to both the rotors and the liner to obtain the laws of radial,circumferential,axial deformation and stress-strain of the rotors and liner.Furthermore,the pressure at monitoring points was compared with experimental data,validating the accuracy of the results.The results indicate that the outlet flow rate initially increases and subsequently decreases with the rising gas volume fraction,reaching its maximum value at a gas volume fraction of 50%.The pressure exhibits a step-like increase from the inlet to the outlet,remaining nearly constant within individual cavities.The gas volume fraction exhibits a positive correlation with the pressure-boosting capacity of the last-stage screw.The gas phase predominantly accumulates in the screw roots,near the outlet edges,and at the intermeshing zones of the screw rotors throughout the flow passage.The liquid phase exhibits relatively higher velocities at the outlet,the meshing region between the driving and driven screw rotors,and near the screw tips.The radial and circumferential deformations of the rotor reach their maximum at the outlet. Under a gas volume fraction of 95%,the maximum radial and circumferential deformations reach 3.501 7×10-6 m and 3.603 7×10-6 m,respectively.The radial deformation of the liner reaches its maximum at the outlet and exceeds the deformation values in all other directions.The structural strength of both the rotors and the liner meets the requirements under all gas volume fraction conditions.The gas volume fraction influences the pump's outlet flow rate,internal pressure distribution,gas-phase distribution,liquid-phase velocity,and structural deformations;however,it does not affect the structural strength of the rotors and the liner.This study can provide valuable insights for optimizing the geometric profile design of the rotors and clearance control of twin-screw pumps,thereby effectively enhancing their transportation efficiency and operational stability under multiphase flow conditions.

    2025 10 v.53;No.640 [Abstract][OnlineView][Download 3218K]

  • Separation performance study of oil-gas separator in aero-engine lubrication and sealing system

    LI Kening;JIA Xingyun;XIONG Deming;DAI Dali;CHENG Huichuan;ZHANG Zhihong;Ministry of Chemical Safety Education Engineering Research Centre,Beijing University of Chemical Technology;Chongqing Dema High Speed Equipment Engineering Research Institute Co.,Ltd.;Chongqing Dema Magnetic Levitation Technology Co.,Ltd.;China Aero Engine Research Institute;

    To address the effective degassing problem of oil-air mixtures in aero-engine lubrication systems,a dynamic pressure oil-gas separator with a square inlet and simple compact structure is proposed.A combination of simulation and experimental methods was used to analyze its separation performance,and the control variable method was applied to investigate the influence,,laws of flow velocityoil volume fractionand oil droplet size on separation efficiency.The results show that the separation efficiency of the oil-gas separator is highest under high flow velocity and low oil volume fraction conditions;flow velocity has a significant impact on separation performance,achieving a maximum air separation efficiency ηd of 88.8% at 35 m/s;oil volume fraction also notably affects separation performance,reaching a maximum oil separation efficiency ηc of 93.5% at an oil volume fraction of 5% and droplet size of 5 μm.For large droplets with sizes of 15 μm and above,the separation efficiency ηk of this dynamic pressure oil-gas separator approaches 100%.This study can provide references for the development of oil-gas separators with high separation efficiency and low flow resistance.

    2025 10 v.53;No.640 [Abstract][OnlineView][Download 1731K]

  • Review of mathematical models for leakage in scroll compressors

    CAO Feng;HE Shentong;HU Haoyu;YANG Xu;School of Energy and Power Engineering,Xi'an Jiaotong University;

    Leakage research in scroll compressors is crucial for their theoretical simulation,structural design,and performance analysis.This paper introduces two main leakage pathways in scroll compressors,reviews research achievements by domestic and international scholars,analyzes and compares leakage calculation models based on 3D CFD and 1D simulation,and discusses property mixing methods when considering lubricating oil. For 3D leakage calculations,studies mostly use software such as Fluent,CFX,PumpLinx,and Simerics MP+,primarily focusing on performance optimization or impact through structural modifications;1D calculations mainly employ modified nozzle models,parallel plate flow models,incompressible viscous flow models,etc.,emphasizing performance improvement and model prediction accuracy,with most models requiring experimental correction and having specific applicable operating ranges.The research results indicate that clearance size significantly affects leakage outcomes,while channel shape,roughness,and lubricating oil also influence leakage behavior;when considering lubricating oil,the working fluid and oil are typically treated as a homogeneous mixture.Regarding sealing method improvements,theoretical and experimental research can be conducted on novel flow structures.In terms of different research approaches,future 3D CFD simulations could develop towards systematization,fluid-structure coupling,and integration with reverse engineering and artificial intelligence;1D simulations should incorporate heat transfer and variable working fluid conditions,further optimizing leakage predictions by combining Fanno flow models,oil-containing conditions,and two-phase flow models. This study can provide references for the development and performance optimization of scroll compressors.

    2025 10 v.53;No.640 [Abstract][OnlineView][Download 1719K]

  • Study on flow and heat transfer characteristics of surface tension tank based on heat capacity method

    ZHAI Lulu;ZHANG Liang;ZHU Zuchao;LIU Jintao;LI Wen;Zhejiang Key Laboratory of Multiflow and Fluid Machinery,Zhejiang Sci-Tech University;Hefei General Machinery Research Institute Co.,Ltd.;Beijing Institute of Control Engineering;

    To achieve accurate measurement of residual propellant in on-orbit satellites,based on thermal-fluid-structure coupling calculation method,numerical calculations were conducted on the transient flow and heat transfer characteristics of propellant during heat capacity measurement.The flow characteristics,temperature distribution,and heat flux distribution characteristics of propellant in the tank under different settling acceleration conditions were analyzed.By comparing real-time temperature change data from simulation and experimental monitoring points,the accuracy of the numerical calculation model was verified.The results show that the sloshing frequency of liquid propellant in the tank increases with increasing settling acceleration.When settling acceleration increases from 0.066 5 m/s~2 to 0.294 m/s~2,the propellant sloshing frequency increases from 0.055 Hz to 0.116 Hz.The temperature change of fluid above the gas-liquid interface is more significant compared to that below the interface.After continuously heating the tank surface at 180 W total power for 180 seconds,there exists a certain temperature difference between,the outer wall of the tank and the fluid-structure interfacewith an average temperature difference of 0.12 K.The lower the monitoring point position,the slower the temperature rises.The main frequency of temperature change at monitoring points inside the tank is consistent with the variation in liquid propellant sloshing frequency.The research results can provide references for the measurement of residual propellant quantity in on-orbit satellites.

    2025 10 v.53;No.640 [Abstract][OnlineView][Download 2612K]

  • Optimization study on atomization performance of external-mix air-atomizing nozzle based on surrogate model

    SUN Zegang;ZHENG Zhonghao;LIU Yu;WANG Zhuomin;School of Mechanical Engineering,Sichuan University of Science & Engineering;

    To investigate the influence of operating parameters on the atomization performance of external-mix air-atomizing nozzles and determine the optimal operating parameters for achieving the best atomization effect,a combined method of finite element model construction and optimization calculation was adopted for relevant research.Using gas inlet pressure,liquid inlet pressure,and liquid kinematic viscosity as optimization variables,and atomization cone angle and outlet flow coefficient as optimization objectives,an orthogonal experiment was designed and conducted. Based on the orthogonal experimental data,a response surface surrogate model was established,and this surrogate model was optimized using genetic algorithm,followed by simulation verification and comparative analysis of results.The results show that gas inlet pressure,liquid inlet pressure,and liquid kinematic viscosity all have significant effects on nozzle atomization performance;when the gas inlet pressure is 0.057 2 MPa,liquid inlet pressure is 0.111 2 MPa,and liquid kinematic viscosity is 0.057 3 Pa·s,the nozzle atomization performance reaches its optimum.Compared with the original model,the atomization cone angle increases by 34.62%,and the outlet flow coefficient improves by 49.36%.The research can provide references for the setting of operating parameters for nozzles.

    2025 10 v.53;No.640 [Abstract][OnlineView][Download 1562K]

  • Study on the influence of circumferential groove casing treatment on cavitation characteristics of axial flow pumps

    TONG Zhiting;LU Xiangbin;SU Hongran;ZHANG Gongyuan;ZHANG Yue;Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System;National Demonstration Center for Experimental Mechanical and Electrical Engineering Education,Tianjin University of Technology;Fujian Qiaolong Emergency Equipment Co.,Ltd.;

    To mitigate cavitation issues in low-lift submersible axial flow pumps during operation,a method inspired by the use of circumferential groove casing treatment for stability enhancement in compressors was proposed. This approach involved applying circumferential groove casing treatment to axial flow pumps. Seven different casing treatment schemes were designed,and their effects on the cavitation performance of the pump were investigated through steady-state numerical simulations using the SST k-ω turbulence model and the Zwart-Gerber-Belamri cavitation model. The study focused on three key parameters:the installation position,width,and depth of the circumferential grooves.The results indicate that cavitation is primarily caused by low-pressure regions formed by the leakage flow at the blade tip.After installing the circumferential grooves,the pump head experienced some loss,with the installation position of the grooves having the most significant impact on cavitation performance. Compared to a smooth wall casing, cavitation occurred earlier when the groove is positioned at 10% of the axial chord length, while the best anti-cavitation performance is achieved when the groove is located at 45% of the leading edge of the axial chord length at the blade tip,reducing the required net positive suction head(NPSH) by 2.9%. Among three groups of grooves with different widths, it was found that as the groove width increased, the pump's anti-cavitation performance improved, with the maximum NPSH,,reduction reaching 4.01%although this also led to increased head loss.Additionallythree grooves with different heights all resulted in a 2.9% reduction in NPSH,indicating that groove height has a relatively minor impact on cavitation performance. The findings of this study provide a theoretical basis for suppressing cavitation in water pumps.

    2025 10 v.53;No.640 [Abstract][OnlineView][Download 2097K]
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