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Effect of rotor-mounted protrusion on sealing performance and flow structure in rotor-stator cavity

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Chinese Journal of Aeronautics 2018年第11期31卷 2057-2072页

作者： Nan CAO Xiang LUO zeyu wu Jie WEN National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics School of Energy and Power EngineeringBeihang UniversityBeijing 100083China Collaborative Innovation Center for Advanced Aero-Engine Beijing 100083China

This paper presents an experimental investigation on the effect of protrusion radial position and height on the sealing performance and flow structure in the rotor-stator cavity. The rotormounted protrusions are assembled at three radial positions and are set to three heights. The cavity is equipped with three rim seals: a radial seal, an axial seal and a seal with double fins on the *** annulus Reynolds number is set at 4:39 ×10;and the rotational Reynolds number ranges from 7:51×10;to 1:20×10;. Heat and mass transfer analogy is applied. Pressure and CO;concentration are measured. The experimental results show that in cavities with different rim seals, radial distributions of the sealing efficiency, pressure and swirl ratio are basically the same. The sealing performance is improved by protrusions compared with the cavity without protrusion and improves with the increase of protrusion radial position and height. The effect of protrusion increases with the increase of the rotational Reynolds number. The windage loss and the flow resistance introduced by protrusions are investigated. It is found that induced windage loss and flow resistance decrease with the increase of protrusion radial position but increase with the protrusion height.

关键词： Height Protrusion Radial position Rim seal Sealing performance

Effect of protrusion amount on gas ingestion of radial rim seal

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Chinese Journal of Aeronautics 2020年第3期33卷 893-901页

作者： zeyu wu Xiang LUO Nan CAO Xue LI Hang CHEN School of Energy and Power Engineering Beihang UniversityBeijing 100083China National Key Laboratory of Science and Technology on Aero-Engine Aero-thermodynamics Beihang UniversityBeijing 100083China

In this paper, the effect of different amount of protrusion on various parameters in rotor–stator system was experimentally studied by measuring CO_2 concentration and pressure, in order to obtain the optimal protrusion *** parameters of different dimensionless sealing flow were measured under the condition that the annulus Reynolds number was 4.39 × 10~5 and the rotating Reynolds number was 1.05 × 10~*** results show that the change of the amount of protrusions has little effect on the static pressure in the cavity, and the static pressure change near the sealing ring is almost *** the total pressure and sealing efficiency increase first and then decrease with the increase of the amount of *** variation of power consumption is the same.A complex vortex structure will appear at the high radius region when the protrusion is *** the other hand, the protrusion can effectively reduce the minimum sealing flow of the rotor–stator ***, considering the sealing efficiency and power consumption,the best range of the protrusion amount is about *** ratio near this range can optimally balance the alleviation of the gas ingestion and the reduction of the power consumption.

关键词： Gas ingestion Protrusion amount Radial seal Rotor–stator cavity Sealing efficiency Turbine

Effect of the protrusion shape on gas ingestion of two sealing structures

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Chinese Journal of Aeronautics 2021年第4期34卷 320-331页

作者： zeyu wu Xiang LUO Jianqin ZHU Hang CHEN Jiahua LIU School of Energy and Power Engineering Beihang UniversityBeijing 100083China National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics Beihang UniversityBeijing 100083China

The windage loss caused by protrusion in a rotor–stator cavity has been studied in detail,and there are abundant fitting formulas that have been summarized to calculate the moment *** other theorists have emphasized its effect on the sealing efficiency,proposing that installation of protrusion could alleviate gas ***,the protrusion shape which is an influential factor on the sealing efficiency has not been focused in previous *** the experimental method of measuring CO2 volume fraction,cavity pressure,and power consumption,we investigated the effects of several typical protrusion shapes on various parameters for two sealing structures,in order to obtain the optimal *** showed that a variation of the protrusion shape had little impact on the static pressure,but the total pressure and the sealing efficiency increased in different ***,even though the hexagon shape resulted in the highest sealing efficiency,we observed that the drop shape had the best overall performance in all of the eight models,which could result in higher efficiency of the turbine *** combination of a radial seal structure and protrusion could improve sealing efficiency better.

关键词： Axial seal Cavity Gas ingestion Protrusion shape Radial seal Sealing efficiency Turbine

Flow characteristics of radial inflow in impeller rear cavity with baffle plate

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Chinese Journal of Aeronautics 2024年第2期37卷 270-282页

作者： Yang BAI Xiang LUO Dongdong LIU zeyu wu Xiaoqiang ZHANG Sipeng WANG Research Institute of Aero-Engine Beihang UniversityBeijing 100191China National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics Beihang UniversityBeijing 100191China School of Energy and Power Engineering Beihang UniversityBeijing 100191China

The research purpose of this paper is to explore the influence of the baffle plate on the airflow in the rear cavity of the centrifugal impeller and optimize the performance of the secondary air system’s air bleed *** this paper,a comprehensive experimental study was carried out on the flow characteristics in the impeller rear cavity with baffle *** windage torque,flow structure and pressure drop between inlet and outlet were measured *** experiment was carried out with the condition that the range of rotational Reynolds number was from 8.33×10^(5)to 22.2×10^(5)and the range of mass flow rate coefficient was from 0.92×10^(4)to 2.92×10^(4).The results show that the static cavity and the narrow stator-rotor cavity formed by the baffle plate effectively suppress the overall swirl coefficient in the ***,the static pressure and total pressure drop in the rotor-stator cavity were *** influence of the baffle plate on the windage torque of the rotary disk is related to the turbulence *** large turbulence parameters,the windage torque would be reduced with baffle plate,while under small turbulence parameters,the baffle plate would increase with baffle *** general,the baffle plate can improve the flow capacity and optimize the bleed air performance with proper structure and operation conditions.

关键词： Impeller rear cavity Baffle plate Flow structure Windage torque Pressure drop

Physics-Informed AI Surrogates for Day-Ahead Wind Power Probabilistic Forecasting with Incomplete Data for Smart Grid in Smart Cities

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Computer Modeling in Engineering & Sciences 2023年第10期137卷 527-554页

作者： zeyu wu Bo Sun Qiang Feng Zili Wang Junlin Pan School of Reliability and Systems Engineering Beihang UniversityBeijingChina Institute of Reliability Engineering Beihang UniversityBeijingChina

Due to the high inherent uncertainty of renewable energy,probabilistic day-ahead wind power forecasting is crucial for modeling and controlling the uncertainty of renewable energy smart grids in smart ***,the accuracy and reliability of high-resolution day-ahead wind power forecasting are constrained by unreliable local weather prediction and incomplete power generation *** article proposes a physics-informed artificial intelligence(AI)surrogates method to augment the incomplete dataset and quantify its uncertainty to improve wind power forecasting *** incomplete dataset,built with numerical weather prediction data,historical wind power generation,and weather factors data,is augmented based on generative adversarial *** augmentation,the enriched data is then fed into a multiple AI surrogates model constructed by two extreme learning machine networks to train the forecasting model for wind ***,the forecasting models’accuracy and generalization ability are improved by mining the implicit physics information from the incomplete *** incomplete dataset gathered from a wind farm in North China,containing only 15 days of weather and wind power generation data withmissing points caused by occasional shutdowns,is utilized to verify the proposed method’s *** with other probabilistic forecastingmethods,the proposed method shows better accuracy and probabilistic performance on the same incomplete dataset,which highlights its potential for more flexible and sensitive maintenance of smart grids in smart cities.

关键词： Physics-informed method probabilistic forecasting wind power generative adversarial network extreme learning machine day-ahead forecasting incomplete data smart grids

Evaluation of the harmonic scalpel in open surgery for abdominal aortic aneurysm

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Frontiers of Medicine 2012年第1期6卷 85-88页

作者： zeyu wu Zhe Chen Lin Peng Department of Vascular Surgery Guangdong General HospitalGuangdong Academy of Medical SciencesGuangzhou 510080China

The harmonic scalpel is a hemostatic device primarily designed for use in laparoscopic *** the last few years,many surgeons have begun to use the harmonic scalpel in open *** papers have cited the benefits of the device compared with conventional knot-tying techniques;however,no evidence showing the advantages of using the harmonic scalpel in complicated abdominal aortic aneurysm(AAA)surgery has been *** aim of the present study is to determine the value of the harmonic scalpel in open operation for AAA.A total of 153 patients who underwent open surgery for AAA at the Department of Vascular Surgery of Guangdong General Hospital,China between January 2001 and December 2010,were retrospectively *** surgery performed with the harmonic scalpel on 105 patients was compared with open operation using conventional knot-tying techniques on 48 *** operative time,intraoperative blood loss,total postoperative drainage fluid volumes,hospital stay,and postoperative complications between the two groups were *** harmonic scalpel group was associated with a shorter operation time(113.2±23.6 min vs.232.1±39.2 min,P<0.01)and lower intraoperative blood loss(126.1±96.6 ml vs.592.1±207.2 ml,P<0.01).Postoperative drainage fluid volumes were greater in the conventional surgery group than in the harmonic scalpel group(702.1±192.8 ml vs.198.5±97.4 ml,P<0.01).The hospital stay was shorter for the harmonic scalpel group than for the conventional surgery group(10.7±3.3 d vs.16.5±4.7 d,P<0.05).No differences between the postoperative complications or hospital mortality of the two groups were *** harmonic scalpel is a safe and minimally invasive tool in open surgery for AAA and is associated with shorter operative time,shorter hospital stay,and lower intraoperative blood loss and postoperative drainage fluid volumes compared with conventional knot-tying techniques.

关键词： abdominal aortic aneurysm harmonic scalpel minimally invasive

Experimental and computational investigation on flow characteristics of rotating cavities with high inlet pre-swirl axial throughflow

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Chinese Journal of Aeronautics 2024年第4期37卷 276-293页

作者： Sipeng WANG Xiang LUO Linji GUO zeyu wu Yang BAI Zongchao LI Lichun MA School of Energy and Power Engineering Beihang UniversityBeijing 100191China Research Institude of Aero-Enigine Beihang UniversityBeijing 100191China National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics Beihang UniversityBeijing 100191China Shenyang Aeroengine Research Institute Aero Engine Corporation of ChinaShenyang 110015China

As an integral part of the internal air system of aero-engines,the axial throughflow of the cooling air can interact with the cavity flow between the rotating compressor disks,forming a threedimensional,unsteady,and unstable flow *** flow characteristics in an engine-like rotating multi-stage cavity with throughflow were investigated using particle image velocimetry,flow visualization technology and three-dimensional unsteady Reynolds-Averaged Navier-Stokes (RANS)*** focus of current research was to understand the distribution of the mean swirl ratio and its variation with a wide range of non-dimensional parameters in the co-rotating cavity with high inlet pre-swirl axial *** maximum axial Reynolds number and rotational Reynolds numbers could reach 4.41×10^(4)and 1.24×10^(6),*** velocity measurement results indicate that the mean swirl ratio is greater than 1 and decreases with an increase in the radial *** flow structure is dominated by the Rossby number,and two different flow patterns (flow penetration and flow stratification) are identified and confirmed by flow visualization *** the absence of buoyancy,the flow penetration caused by the precession of the throughflow makes it easier for the throughflow to reach a high radius *** consistency of results between measurements and numerical calculations is *** study provides a theoretical basis and data support for toroidal vortex breakdown,which is of practical significance for the design of high-pressure compressor cavities.

关键词： Compressor Axial throughflow Rotating cavity flow Particle image velocimetry Unsteady RANS Flow pattern

Sealing efficiency performance of four different rim seals in turbine cavity

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Chinese Journal of Aeronautics 2024年第12期37卷 347-357页

作者： zeyu wu Dongdong LIU Sipeng WANG Zhe ZHANG Yang BAI Xiang LUO Research Institute of Aero-Enigine Beihang UniversityBeijing 100191China School of Energy and Power Engineering Beihang UniversityBeijing 100191China National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics Beihang UniversityBeijing 100191China

In modern aero-engine,the turbine rim seals whose purpose is to reduce the ingress are located in a complex flow region between the mainstream and secondary air *** sealing air discharged from the compressor of engine is used to purge turbine *** order to examine the effects of ingress through four distinct rim seals,a one-stage test rig was used in the experiments presented in this *** a Reynolds number of 5.16×10^(5) in the mainstream and(0.85-2.13)×10^(6) in the rotational,the radial pressure distribution on the stator was *** assess flow characteristics and sealing efficacy,measurements of the swirl ratio and CO_(2) concentration were *** reliability of turbine rim-seals is determined by the locations of the hook and teeth,as well as their effect on hot gas *** evaluate the performance of four types of seals:a datum double-rim seal and three derivatives with different clearances,the data are *** to the inlet air position,the swirl ratio exhibited a pronounced inflection for all the rim *** sealing efficiency can be decreased by putting the hook closer to the rim or by taking the teeth *** pressure measurements in the turbine cavity indicate that the seal position has a significant *** analysis results revealed that the existence of slot vortex is beneficial to improving efficiency.

关键词： Turbine Cavity Gas ingestion Rim seal Sealing efficiency

Reverse Rotation of Ring-Shaped Perturbation on Homogeneous Bose–Einstein Condensates

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Chinese Physics Letters 2021年第9期38卷 11-17页

作者： Peng Gao zeyu wu Zhan-Ying Yang Wen-Li Yang School of Physics Northwest UniversityXi’an 710127China Shaanxi Key Laboratory for Theoretical Physics Frontiers Xi’an 710127China Department of Physics and Astronomy University College LondonLondon WC1E 6BTUK Peng Huanwu Center for Fundamental Theory Xi’an 710127China Institute of modern Physics Northwest UniversityXi’an 710127China

We numerically study the dynamics of rotating ring-shaped perturbation on two-dimensional homogeneous Bose–Einstein condensates,where a new ring-shaped structure with reverse rotation *** reversely rotating mode is directly caused by the existence of the plane wave(namely the homogeneous background).By the modified linear stability analysis method,we quantitatively predict the influence of the background’s density on perturbation dynamics,including the velocity,amplitude,and frequency of the two *** construct an approximative solution to describe the short-lived dynamics of initial perturbation,which agrees well with our numerical ***,after the two rings separate,the transfer of atom number between them becomes linear,and the rate of transfer is impacted by the radial momentum of initial perturbation.

关键词： perturbation perturbation Einstein