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Numerical Study on flow Field in a Diameter-Varying Spray Tower for Amine-Based CO2 Absorption

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SSRN 2019年

作者： Wu, Xiaomei Yu, Yunsong Zhang, Zaoxiao Wang, Geoff Rudolph, Victor School of Chemical Engineering and Technology Xi’an Jiaotong University No.28 Xianning West Road Xi’an710049 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

关键词： Greenhouse gases

Experiments and predictions for severe slugging of gas-liquid two-phase flows in a long-distance pipeline-riser system

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Ocean engineering 2024年 301卷

作者： Chang, Yingjie Xu, Qiang Zou, Suifeng Zhao, Xiangyuan Wu, Quanhong Wang, Yechun Thévenin, Dominique Guo, Liejin Shaanxi Key Laboratory of New Transportation Energy and Automotive Energy Saving Chang'an University Xi'an710064 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China Laboratory of Fluid Dynamics and Technical Flows Otto-von-Guericke-Universität Magdeburg Magdeburg39106 Germany

Experiments concerning the flow regimes observed in gas-liquid two-phase flows in a long-distance pipeline-riser system were carried out and analyzed in this paper. The test loop with 0.075 m inner diameter consisted of a 314 m horizontal pipeline, followed by a 25 m downward-inclined pipe, and finally a 21.5 m riser pipe. An industrial-scale global flow regime map including 5 flow regimes was derived from differential pressure measurements in the riser and was used as a reference for improvements. Electrical capacitance volume tomography installed in the horizontal section was used to reconstruct the phase interface and calculate the average gas void fraction (GVF). An appropriate model for this system was selected by comparing the experimental GVF with different, widely used models. The occurrence of severe slugging flow (SS) can be predicted accurately using an improved model involving additional corrections that consider pipeline length, accurate GVF calculation, and gas density. This study supports the development of a suitable SS prediction model enabling safe design, operation, and control of practical systems. © 2024 Elsevier Ltd

关键词： Pipelines

Prediction of thermal performance of radiative radial fin with temperature-dependent thermal conductivity using spectral collocation method

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Journal of Computational and Theoretical Nanoscience 2016年第9期13卷 5822-5831页

作者： Ma, Jing Sun, Ya-Song Li, Ben-Wen Key Laboratory of Shaanxi Province for Development and Application of New Transportation Energy School of Automobile Chang'an University Xi'an710064 China Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy North China Electric Power University Beijing102206 China Institute of Thermal Engineering School of Energy and Power Engineering Dalian University of Technology Dalian116024 China

Spectral collocation method (SCM) is developed to solve coupled radiation and conduction in radiative radial fin with temperature-dependent thermal conductivity and volumetric heat generation. In this approach, energy conservation equation is discretized by SCM, and a particular algorithm is proposed to alleviate the nonlinearity of energy conservation equation. Numerical results by SCM are compared with available results in the literature, which indicate that SCM can provide high accuracy for combined radiative and conductive heat transfer in radiative radial fin, and the integral averaged relative error decreases exponentially with the increasing number of collocation points. Meanwhile, the effects of various parameters on the thermal performance, such as dimensionless thermal conductivity coefficient, radiation-conduction parameter, dimensionless ambient temperature, dimensionless radiation sink temperature and dimensionless volumetric heat generation are also investigated. Copyright © 2016 American Scientific Publishers All rights reserved.

关键词： Fins (heat exchange)

Research on surface damage of solid material subjected to high speed liquid impact

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Binggong Xuebao/Acta Armamentarii 2009年第SUPPL. 2期30卷 139-144页

作者： Xie, Yong-Hui Wang, Yong Chen, Jian-Hui Zhang, Di State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Shaanxi Xi'an 710049 China

In order to study the surface damage of solid material subjected to the high speed liquid impact, both numerical and experimental methods were established. The smoothed particle hydrodynamics and finite element analysis were used to calculate the material damage. The conditions of PMMA and steel were analyzed to obtain the dynamic stress and strain distribution during impact. An experiment apparatus was build. The velocity of the impact jet was measured using a high speed camera and the apparatus. A digital microscope was used to measure the three dimensional profile of the sample before and after high speed liquid impact up to 600 m/s. The dimensions of damage area were recorded and analyzed statistically. Based on the statistical results, the performance of the materials resisting liquid corrosion was evaluated.

关键词： High speed cameras

Numerical investigation on transport characteristic of air breathing direct methanol fuel cell

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Huagong Xuebao/CIESC Journal 2011年第SUPPL. 1期62卷 66-71页

作者： Miao, Zheng Zou, Jinqiang He, Yaling Liu, Zeng State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Xi'an 710049 Shaanxi China

A two-dimensional two-phase non-isothermal mass transport model is developed in this paper for the air breathing direct methanol fuel cell(DMFC). The self-made computer code is used to simulate the heat and mass transport characteristic which is coupled with electro-chemical reactions. The effects of temperature of the inlet methanol solution, temperature of the air, and the feeding concentration of methanol on the performance of the fuel cell are investigated. The numerical results show that the cell performance can be enhanced at a higher temperature of the inlet methanol solution and the air. Cell performance at the higher cell current densities can be improved with a higher feeding concentration of methanol. © All Rights Reserved.

关键词： Heat transfer

Multi-Objective Optimization and Configurations Comparison of Closed-Air Brayton Cycle

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SSRN 2023年

作者： Qian, Yiran Gu, Zhenzhen Song, Meihui Yang, Yi Zhao, Quanbin Chen, Weixiong Yan, Junjie State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China China Institute of Atomic Energy P.O. Box 275-32 Beijing102413 China

Microreactor power system has characteristics of efficient, compact and high environmental adaptability. In this study, closed-air Brayton cycle (CABC) is proposed as the microreactor thermoelectric conversion system, and thermodynamic model of CABC with different configurations are established. The cycle parameters and component’s structure are designed using system-component combined design method. To obtained the optimal system design scheme, the Genetic Algorithm (GA) and the Non-dominated Sorting Genetic Algorithm II (NSGA-II) are separately applied for single-objective optimization and multi-objective optimization. According to multi-objective optimization results, the IRRC has the highest cycle efficiency of 35.4% and the ratio of power to mass of 59.1 kW·t-1 , respectively, and the RRC has the highest power density of 179.6 kW·m-3 . Similar performance with IRRC and simpler structure make the RRC the optimal configuration of CABC. Compared with single-objective optimization, the design results of multi-objective optimization are more balanced in terms of three performance indicators, meaning that the optimized design scheme has a better comprehensive performance. © 2023, The Authors. All rights reserved.

关键词： Multiobjective optimization

Corrosion Effect Analysis on Thermal-Hydraulics of Lbe/Water Spiral Tube Steam Generator Under Oxygen-Controlled Environment

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SSRN 2023年

作者： Lu, Dingsheng Yang, Yupeng Wang, Chenglong Zhang, Dalin Qiao, Pengrui Tian, Wenxi Qiu, Suizheng Su, Guanghui H. School of Nuclear Science and Technology Shanxi Key Laboratory of Advanced Nuclear Energy and Technology Xi'an Jiaotong University Xi'An710049 China China Institute of Atomic Energy Beijing102413 China State Key Laboratory of Multiphase Flow in Power Engineering China

In order to explore the flow and heat transfer characteristics of spiral tube steam generators under Lead-Bismuth Eutectic (LBE) corrosion, the accelerated removal effect of LBE corrosion flow was perfected, and a bidirectional coupling model of LBE corrosion and flow heat transfer was established. Computational fluid dynamics (CFD) method was used to simulate the corrosion and flow heat transfer of helical tube steam generator under saturated oxygen concentration and oxygen-controlled environment. The results indicate that the corrosion of liquid LBE forms an oxidation layer, which hinders the heat transfer in the spiral tube steam generator. This leads to a significant increase in the wall friction coefficient and a decrease in the surface Nusselt number. However, it does not have a significant effect on the water side evaporation process of the spiral tube steam generator. The implementation of an oxygen-controlled environment can effectively reduce the influence of LBE corrosion on the flow heat transfer of the spiral tube steam generator. Especially under high temperature conditions, it can reduce the near wall temperature of LBE change by up to 57.5% and the outlet temperature change by up to 61.5%. The oxygen-controlled environment results in prolonged local hypoxia time, with a more pronounced effect at higher temperatures. © 2023, The Authors. All rights reserved.

关键词： Oxygen

Data Mining-Assisted Multi-Objective Optimization of Blade Angle Distributions for Efficiency and Stability Enhancement of a Free-Form Centrifugal Impeller

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SSRN 2024年

作者： Chen, Zhikai Chen, Ziying Sun, Jieshuai Guo, Yi Spence, Stephen Peng, Xueyuan Feng, Jianmei School of Energy and Power Engineering Xi'an Jiaotong University Xi’an710049 China School of Mechanical Manufacturing and Biomedical Engineering Trinity College Dublin Dublin 2 Ireland State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi’an710049 China

The design optimization process for a centrifugal compressors faces significant trade-offs between efficiency, pressure ratio, and stable operating range. To address this challenge, a data mining assisted-optimization combining machine learning modelling method and non-dominated sorting genetic algorithm III (NSGA-III) has been proposed to enhance efficiency and pressure ratio while considering expansion of operational stability. A validated CFD numerical model was established for data generation. A Light-GBM model with Bayesian hyperparameter tuning and a deep feedforward neural network (DNN) model were constructed, and the better one was selected for performance prediction. Data mining techniques, including Sobol sensitivity analysis and SHAP, were employed to identify the key sensitive parameters and their interactions. Finally, a NSGA-III-based multi-objective optimization was conducted to determine the optimal geometry of the free-form surface impeller. Results showed that the blade angle distributions at the leading edge of mid-span and shroud profile were the most sensitive parameters affecting isentropic efficiency at the design point, with their recommended ranges identified. The optimized impeller has an increase in total pressure ratio of 2.98% and isentropic efficiency of 0.67% at the design point, especially exhibiting excellent aerodynamic performance at higher mass flow rate conditions. The maximum improvements of total pressure ratio and isentropic efficiency were 12.91% and 9.53%, respectively, corresponding to the near choke mass flow rate at the design speed. Additionally, operating stability was expanded with a 1.22% increase in total pressure ratio at near surge mass flow rate at the design speed, which contributed to a delay in the onset of surge. © 2024, The Authors. All rights reserved.

关键词： Sensitivity analysis

Free surface vortex in a rotating barrel with rods of different heights

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International Journal of Fluid Machinery and Systems 2016年第4期9卷 325-331页

作者： Zhang, Xiaoyue Zhang, Min Chen, Wanyu Yang, Fan Guo, Xueyan School of Energy and Power Engineering University of Shanghai for Science and Technology No. 516 Jungong Road Shanghai200093 China Department of Mechanical and Electrical Engineering Henan Mechanical and Electrical Engineering College No. 699 Pingyuan Road Xinxiang453003 China Key Laboratory of Flow Control and Simulation University of Shanghai for Science and Technology No. 516 Jungong Road Shanghai200093 China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering No. 516 Jungong Road Shanghai200093 China

A bathtub vortex above the outlet of a rotating barrel is simulated. By analyzing the Ekman layer theory, it can be found that the main flow circulation is inversely proportional to the thickness of Ekman layer. The thicker the Ekman boundary layer, the weaker the rotational strength and the shorter of the length of gas core is. According to this law, models of barriers with rods of different heights are established. The reduction of air-core length in this air entrainment vortex and weakening the strength of rotation field were achieved. © 2016 Turbomachinery Society of Japan. All rights reserved.

关键词： Vortex flow