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A new non-destructive method for fault diagnosis of reciprocating compressor by measuring the piston rod strain

IOP Conference Series: Materials Science and engineering 2019年第1期604卷

作者： Xueying Li Xueyuan Peng Xi'an Jiaotong University Xi'an Jiaotong University Xi'an 710049 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

As an established method to analyse the thermodynamic process inside the cylinder, the p-V diagram can identify typical faults such as leakages through the sealing rings and self-acting valves, loosening and fluttering of the vales, etc. However, the installation of the pressure sensor within the cylinder for recording the p-V diagram may lead to degradation of the cylinder integrity, and hereby potential leakage and lowered strength of the cylinder. This paper presents a new non-destructive method for fault diagnosis of the reciprocating compressor by measuring the piston rod strain, from which the p-V diagram was transformed. An algorithm for reconstruction of the p-V diagram was proposed based on the key feature points on the piston rod load curve that reflect the opening and closing events of the compressor valves. The reconstruction method was validated by comparing the calculated p-V diagrams with the experimental results. The reconstructed p-V diagrams were further used for fault diagnosis of the reciprocating compressors, with which the acoustic emission method was integrated. The results show that this method can easily monitor the working conditions and identify whether and where leakage, fluttering and delayed closing of the valves occur, which indicates that this method can be utilized as a powerful tool of non-destructive condition monitoring and fault diagnosis of the reciprocating compressors.

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Pressure drop of single/two-phase flows through porous bed with sand particles 17

Pressure drop of single/two-phase flows through porous bed w...

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17th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2017

作者： Li, Liangxing Kong, Liubo Wang, Huasheng Zou, Xumao Lei, Xianliang Li, Huixiong State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xian-ning West Road 28# Xi’an city710049 China

Motivated by reducing the uncertainties in quantification of debris bed coolability in a severe accident of light water reactors (LWRs), this paper reports experimental studies on the pressure drops of single /two phase flows through packed porous beds with sand particles. A test facility named DEBECO-LT is constructed to investigate the friction laws of adiabatic single and two-phase flow through a particulate bed. From the single flow test, the effective diameter of bed with sands particles can be derived from the measured pressure drops and the Ergun equation. Based on this effective diameter, two phase flow tests are performed and the prediction models are verified by comparing the measured data and the calculations with different analysis models. The results show that in the case of beds with smaller sands particles, the measured pressure drops show gradual increasing tendency with fluid flowrate, and the predictions of Reed model are closer to the measured two-phase flow pressure drop at higher flowrates. For the packed beds with coarse sands particles, the pressure drops would show descent-ascent tendency and there were hardly any models predicting well the measured pressure drop. There is a clear need to develop an accurate analysis models for the bed with coarse particles. © 2016 Association for Computing Machinery Inc. All Rights Reserved.

关键词： Pressure drop

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Corrigendum to “Promoting adiabatic core approximation in a rapid compression machine by an optimized creviced piston design” [Fuel 251 (2019) 328–340]

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Fuel 2019年 255卷

作者： Yingtao Wu Meng Yang Chenglong Tang Yang Liu Peng Zhang Zuohua Huang State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an 710049 China Department of Mechanical Engineering The Hong Kong Polytechnic University Hung Hom Kowloon Hong Kong

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Deformation and Motion of Compound Droplet Adhering to Wall

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Kung Cheng Je Wu Li Hsueh Pao/Journal of engineering Thermophysics 2017年第12期38卷 2636-2640页

作者： Shang, Xing-Long Bai, Bo-Feng State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

The compound droplet will exhibits much more complex behavior when it adheres to a wall under flow. Studying the influence of related parameter plays an important role in the manipulation of the compound droplet. In this paper, a three-dimensional numerical method involving the moving contact line problem is developed by integrating the generalized Navier boundary condition into the front-tracking method. The proposed method is applied to study the effects of the capillary number of inner and outer interface and the volume of inner droplet on the deformation and motion of the compound droplet adhering to the wall with considering the contact angle hysteresis effect. It found that the compound droplet is more like to be detached or pinched-off by the flow when the capillary number of outer interface and the volume of inner droplet are large and the capillary number of inner interface is small. key words © 2017, Science Press. All right reserved.

关键词： Deformation

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Effects of Fluid Inertia on Adhesion Behaviors of Elastic Capsules

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Kung Cheng Je Wu Li Hsueh Pao/Journal of engineering Thermophysics 2017年第4期38卷 776-780页

作者： Luo, Zheng-Yuan Bai, Bo-Feng State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

Elastic capsules (consisting of viscous fluid enclosed by elastic membranes) can form specific adhesion bonds with functionalized surface. Adhesion force in these bonds and viscous and inertial force in fluids determine adhesive dynamics of capsules under flow. In this paper, based on the front-tracking finite-element method we developed previously, we further combine the kinetic adhesion dynamics model and develop a three-dimensional model for adhesive dynamics of capsules, in which membrane elasticity, fluid inertia and viscosity can be considered simultaneously. The effects of fluid inertia on adhesive characteristics of capsules are investigated systematically. Results show that fluid inertia induces the increase of both drag and lift forces from the surrounding fluid. As a consequent, the detachment of the elastic capsule is promoted by fluid inertia. © 2017, Science Press. All right reserved.

关键词： Dynamics

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On the effects of shear and compositional inhomogeneities in turbulent, lean, premixed flames 11

On the effects of shear and compositional inhomogeneities in...

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11th Asia-Pacific Conference on Combustion, ASPACC 2017

作者： Steinmetz, S.A. Juddoo, M. Jin, W. Masri, A.R. School of Aerospace Mechanical and Mechatronic Engineering University of Sydney NSW2006 Australia State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xian710049 China

This paper presents some initial results on the separate effects of shear and compositional inhomogeneities on the global structure of turbulent lean piloted premixed flames. Shear is introduced by injecting the mixture in two streams through two concentric tubes at different velocities. Compositional inhomogeneity, for the same shear rate, is obtained by injecting air in the annulus and fuel or rich fuel-air mixtures through the inner jet which may be recessed upstream of the jet exit plane. It is found that increasing the shear inhomogeneity can lead to a shorter flame where the tip may transition from "open" to "closed". The latter refers to a "Bunsen-like" flame while an "open" flame has reacting edges that do not close at the tip. Compositional inhomogeneity seems to have little effects on the global structure despite the presence of mixture fraction gradients a noted from Rayleigh scattering performed the jet exit plane. Measurements of velocity fields and imaging of reaction zones will be performed to enable a better understanding of the structure of these flames and to locate them on the premixed flames regime diagram. © 2018 Combustion Institute. All Rights Reserved.

关键词： Mixtures

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Numerical study on the laminar flame characteristics of acetylene-methanol blends 11

Numerical study on the laminar flame characteristics of acet...

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11th Asia-Pacific Conference on Combustion, ASPACC 2017

作者： Li, Qianqian Zhang, Yemiao Zhang, Yingjia Huang, Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University No. 28th Xianning West Road Xi’anShaanxi710049 China

Laminar flame characteristics of the blends of acetylene and methanol were numerically studied at 0.1 MPa and 363 K. A model was adopted to do the simulations with the accuracy validated with published laminar flame speeds data of methanol and acetylene. Simulation results showed that the methanol addition into acetylene leads to the significant increase of laminar flame speed with the equivalence ratio corresponding the maximum value shifting to the rich side. The reasons behind were analyzed and found the thermal and chemical kinetic effects both contribute the laminar flame speed variation while the contribution of the diffusion effect can be ignored. Besides, the equivalence ratio shift is found to be closely related to the adiabatic temperature and OH concentrations.

关键词： Acetylene

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Performance of V-Cone flowmeter applied to cryogenic fluid measurement considering cavitation

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IOP Conference Series: Earth and Environmental Science 2019年第6期240卷

作者： Denghui He Bofeng Bai Senlin Chen Jie Zhang Pengcheng Guo State Key Laboratory of Eco-hydraulic in Northwest Arid Region Xi'an University of Technology Xi'an 710048 Shaanxi China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 Shaanxi China

The V-Cone flowmeter is a promising differential pressure flowmeter for metering the cryogenic fluid for its many advantages. When the cryogen velocity increases to a certain value, the cavitation may occur in flowmeter, which may significantly affect the performance of V-Cone flowmeter. However, the effect of cavitation on performance of V-Cone flowmeter remains unclear and there are no published studies to our knowledge on this issue. Here we investigate the performance of V-Cone flowmeter when measuring the cryogenic fluids, especially the effects of cavitation on the discharge coefficient and pressure loss coefficient of the flowmeter. Two cryogenic fluids are investigated, including liquid nitrogen (LN2) and liquid hydrogen (LH2). For comparison, the water is also investigated. The realizable κ-ε model is used to describe the turbulence. The Schnerr-Sauer cavitation model is used to investigate the effect of cavitation on the performance of the V-Cone flowmeter. The results show that there was little effect of cavitation on the discharge coefficient and pressure loss coefficient at the initial stage of cavitation. When the cloud cavitation occurred downstream of V-Cone, the discharge coefficient decreases rapidly with Reynolds number increasing, while the pressure loss coefficient rises quickly. The average discharge coefficient is almost the same for different fluids in the stable region; while the cryogenic fluids have wider stable Reynolds number ranges than the water. The lower limits of the Reynolds number for the constant discharge coefficient is very close for three fluids, however, for the upper limits of Reynolds number are quite different. We conclude that measurement range of the cryogenic fluid is much larger than that of the water, which shows that the V-Cone flowmeter exhibits great potential in the measurement of cryogenic fluid. This study provides insights into the effect of cavitation on the measurement of V-Cone flowmeter and opens a new aven

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Optimization of the fuel rod＇s arrangement cooled by turbulentnanofluids flow in pressurized water reactor (PWR)

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Chinese Journal of Chemical engineering 2017年第6期25卷 722-731页

作者： M. Hatami MJ.Z. Ganfi I. Sohrabiasl D. Jing International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering Xi'anJiaotong University Xi'an 710049 China Department of Mechanical Engineering Esfarayen University of Technology Esfarayen North Khorasan lran Department of Renewable Energies Engineering Faculty of New Sdences & Technologies University of Tehran Tehran lran Department of Mechanical Engineering Babol University of Technology Babol lran

In this paper, response surface methodology(RSM) based on central composite design(CCD) is applied to obtain an optimization design for the fuel rod's diameter and distance cooled by turbulent Al_2O_3–water nanofluid for a typical pressurized water reactor(PWR). Fuel rods and nanofluid flow between them are simulated 3D using computational fluid dynamics(CFD) by ANSYS-FLUNET package software. The RNG k–ε model is used to simulate turbulent nanofluid flow between the rods. The effect of different nanoparticles concentration is also investigated on the Nusselt number from heat transfer efficiency view point. Results reveal that when distance parameter(a) is in the minimum level and diameter parameter(r) is in the maximum possible level, cooling the rods will be better due to higher Nusselt number in this situation. Also, using the different nanoparticles on the cooling process confirms that Al_2O_3 averagely 17% and TiO_2 10% improve the Nusselt numbers.

关键词： Optimization Fuel rods Nanofluid Pressurized water reactor

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Experimental research on the characteristics of steam-water counter-current flow in the Pressurizer Surge Line assembly

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Experimental Thermal and Fluid Science 2018年 96卷 180-191页

作者： Jiangtao Yu Dalin Zhang Leitai Shi Zhiwei Wang Wenxi Tian G.H. Su S.Z. Qiu State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University 28 Xianning West Road Xi’an 710049 China Shaanxi Key Lab. of Advanced Nuclear Energy and Technology School of Nuclear Science and Technology Xi’an Jiaotong University 28 Xianning West Road Xi’an 710049 China

To investigate Counter-Current flow (CCF) characteristics in the Pressurizer Surge Line (PZR SL) assembly of the large advanced passive nuclear reactors, steam-water CCF experiments are carried out on a stainless steel test section, which is a 1:4 scaled-down model of the AP1000 PZR SL assembly. The inner diameter of the test PZR SL pipe is 90 mm, which also belongs to the large-diameter pipes, as same as the prototype PZR SL pipe, in the field of Counter-Current flow Limitation (CCFL) researches. The present steam-water CCFL experiments are conducted under normal pressure and saturated temperature, with the PZR simulator collapse water level ranging from 350 to 900 mm. CCFL becomes severer at higher steam flow rate, and the most limiting CCFL effect locates between the PZR simulator bottom head and the vertical part of PZR SL pipe. The onset of CCFL and zero liquid penetration (ZP) are two critical conditions in the CCF development process, dividing the process into three stages: Before-CCFL, Partial-CCFL, and CCFL-ZP. According to the local CCFL conditions, the development of the CCFL process is also divided into four-regions since onset of CCFL. The present steam-water CCF data are well normalized in terms of dimensionless Kutateladze (Ku) numbers, and a Ku-type empirical partial CCFL correlation is developed. The comparisons of the present CCF data and partial CCFL correlation with the CCF data and correlations of former experiment researches validate that the present empirical partial CCFL correlation is conservative to predict steam-water partial CCFL in the prototype PZR SL assembly of the large advanced passive nuclear reactors.

关键词： Steam-water counter-current flow Partial CCFL correlation Pressurizer surge line assembly Advanced passive nuclear reactors ADS Automatic Depressurization System ADS1-3 First to Third Stages of ADS ADS4 Fourth Stage of ADS CCF Counter-Current flow CCFL Counter-Current flow Limitation CCFL-1 The 1st grade of CCFL region CCFL-2 The 2nd grade of CCFL region CCFL-3 The 3rd grade of CCFL region CCFL-L Local CCFL at the T-junction of HL pipe and PZR SL pipe CCFL-S Local CCFL along the PZR SL pipe CCFL-U Local CCFL at the location between the PZR simulator bottom head and vertical part of PZR SL pipe CCFL-ZP Zero liquid penetration region or stage CMT Core Makeup Tank COCF Co-Current flow HL Hot Leg IRWST In-containment Refueling Water Storage Tank Ku Kutateladze PRHR Passive Containment Cooling System PWRs Pressurized Water Reactors PZR SL Pressurizer Surge Line RC Reactor Core RCS Reactor Coolant System RPV Reactor Pressure Vessel SBLOCAs Small-Break Loss-of-Coolant Accidents ZP zero liquid penetration

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