检索结果-内蒙古大学图书馆

SSRN 2022年

作者： Wang, Jinzhi Xie, Xiangdong Wang, Yechun Xu, Qiang Wang, Jiang Guo, Liejin State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

The flow around cylinder is widely used in industrial applications. In this study, the separation characteristics of gas-liquid two-phase flow around a perforated tube are investigated experimentally. The interface fluctuation process of the gas pocket and liquid slug periodic separation around the perforated tube is presented intuitively using a high-speed camera. The mean value and standard deviation of the void fraction in the wake region are independent of the inlet liquid flow rate. When the flow pattern is plug flow, the air separation efficiency first decreases and then increases with an increase in the inlet void fraction;the separation efficiency increases monotonically when the flow pattern is slug flow. The separation purity and total pressure drop increase with increasing inlet void fraction. Based on the principle of minimum kinetic energy, methods for predicting the void fraction in the wake region, separation purity, air separation efficiency and pressure drop have been developed. The new correlations are based on the Weber number and liquid-phase Reynolds number that are also controlling dimensionless group in determining the void fraction, separation efficiency and pressure drop. The prediction accuracies of the void fraction and separation purity are within ±10% and the prediction accuracies of the separation efficiency and pressure drop are within ±20%, which provides an accurate prediction of the separated flow around the perforated tube. © 2022, The Authors. All rights reserved.

关键词： Void fraction

来源：评论

学校读者我要写书评

暂无评论

Improving sampling depth of laser speckle imaging by topical optical clearing:A theoretical and in vivo study

引用

Journal of Innovative Optical Health Sciences 2020年第2期13卷 33-43页

作者： D.Li Y.Zhang B.Chen State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an Shaanxi 710049P.R.China

The effect of optical cleaning method combined with laser speckle imaging(LSI)was discussed to improve the detection depth of LSI due to high scattering characteristics of skin,which limit its clinical application.A double-layer skin tissue model embedded with a single blood vessel was established,and the Monte Carlo method was used to simulate photon propagation under the action of light-permeating agent.808 nm semiconductor and 632.8 nm He–Ne lasers were selected to study the e®ect of optical clearing agents(OCAs)on photon deposition in *** show that the photon energy deposition density in the epidermis increases with the amount of tissue°uid replaced by *** with glucose solution,polyethylene glycol 400(PEG 400)and glycerol can considerably increase the average penetration depth of photons in the skin tissue,thereby raising the sampling depth of the *** the action of glycerol,PEG 400,and glucose,the average photon penetration depth is increased by 51.78%,51.06%,and 21.51%for 808nm,68.93%,67.94%,and 26.67%for 632.8 nm lasers,*** vivo experiment by dorsal skin chamber proves that glycerol can cause a substantial decrease in blood°ow rate,whereas PEG 400 can signicantly improve the capability of light penetration without a®ecting blood velocity,which exhibits considerable potential in the monitoring of blood°ow in skin tissues.

关键词： Laser speckle image topical optical clearing imaging depth Monte-Carlo simulation dorsal skin experiment

来源：评论

学校读者我要写书评

暂无评论

A novel mid-temperature chemical looping system with near-zero carbon emissions for hydrogen and power coproduction

引用

Energy 2025年 329卷

作者： Li, Yang Fang, Yu Liu, Mingkai Liu, Kai Gai, Zhongrui Shen, Yuanhui Zhang, Ruqi Pan, Ying Jin, Hongguang Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing100190 China University of Chinese Academy of Sciences Beijing100049 China International Research Center for Renewable Energy & State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

Designing an efficient system for conversion of fossil fuel to hydrogen with lower environmental impact represents a promising strategy to meet the demands of a low-carbon future society. This study introduces an integrated chemical looping system combining hydrogen production and combustion for low-carbon fossil fuel conversion. The system achieves hydrogen production at 600 °C, significantly lower than conventional steam methane reforming (850 °C). Moreover, chemical looping combustion is employed to enable efficient CO2 capture. The proposed system is investigated from key reactions, system performance, and economic feasibility aspects. Experimental results show 80 % methane conversion, a hydrogen yield of 2.6 in the hydrogen production process, and nearly 100 % CO2 purity from purge gas combustion. Thermodynamic analysis reveals the energy and exergy efficiencies of 74.3 % and 68.9 %, surpassing the reference system by 3.6 % and 4.1 %, respectively. Economic assessment indicates a 10 % reduction in the levelized cost of hydrogen compared to the reference system. 1000 consecutive cycles confirm the outstanding stability of the oxygen carrier particles for the system. This study demonstrates the system's feasibility, cost-effectiveness, and potential for sustainable hydrogen production with minimal environmental impact, introducing a promising method for the efficient utilization of fossil fuels. © 2025 Elsevier Ltd

关键词： Differential thermal analysis

来源：评论

学校读者我要写书评

暂无评论

Experimental Study on Slagging and Fouling Behaviors During Oxy-Fuel Combustion of Zhundong Coal Using a Drop Tube Furnace 9th

Experimental Study on Slagging and Fouling Behaviors During ...

引用

9th International Symposium on Coal Combustion, ISCC 2019

作者： Zhao, Lei Wang, Chang’an Hu, Yueyi Sun, Ruijin Tang, Guantao Guo, Jin Jiang, Zhiming Du, Yongbo Che, Defu State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an710049 China Guangdong Institute of Special Equipment Inspection and Research Foshan528251 China Shunde Institute of Inspection Guangdong Institute of Special Equipment Inspection and Research Foshan528251 China

ISBN: (纸本)9789811616563

Zhundong coal featuring high content of alkali metals induces severe slagging and fouling problems during its utilization in utility boilers. Oxy-fuel combustion technology can achieve a large amount of CO2 capture and reduce the NOx emission. Unfortunately, in-depth investigation has been seldom carried out on the process of ash deposition and slagging of high-alkali coal during oxy-fuel combustion. In the present study, the oxy-fuel combustion of high-alkali coals were experimentally studied using a non-cooled sampling probe in a drop tube furnace. The fouling and slagging mechanisms were investigated in various atmospheres, temperatures and different O2 concentrations. In addition, the slag samples were characterized by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) coupled with Energy Dispersive X-ray Spectrometer (EDS). Experimental results indicated that under air and oxy-fuel conditions with the same O2 content, the types of elements and minerals were almost the same. With the temperature increased, the adhesion between the slag samples was strengthened and the pore structure slag was increased. The degree of slag melting and sintering was aggravated at the temperature of 1200 °C and the slag structure was complicated. As the oxygen concentration was increased, some of the spherical particles had completely melted on the surface of the massive ash, resulting in an uneven surface. The present work can provide new insights into the slagging and ash deposition of Zhundong high-alkali coal during oxy-fuel combustion. © 2022, Tsinghua University Press.

关键词： Coal

来源：评论

学校读者我要写书评

暂无评论

Effect of Chemical Composition on Adsorption and Agglomeration Characteristics of Ash Particles After Sulfuric Acid Adsorption 9th

Effect of Chemical Composition on Adsorption and Agglomerati...

引用

9th International Symposium on Coal Combustion, ISCC 2019

作者： Jiang, Jiahao Yan, Yu Guo, Jin Li, Yuesheng Deng, Lei Che, Defu State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an710049 China Guangdong Institue of Special Equipment Inspection and Research Foshan528251 China Guangdong Institue of Special Equipment Inspection and Research Shunde Institue of Inspection Foshan528300 China

ISBN: (纸本)9789811616563

The low-low temperature electrostatic precipitator has been applied to enhance the efficiency of power plants. In this paper, the influences of chemical constitutions on the adsorption properties of particulate matters with vitriolic acid and the agglomeration after adsorption are researched. Experiments are conducted on a one-dimensional adsorption system, which simulates the working environment of low-low-temperature electrostatic precipitator. The consequences display that the agglomeration between particulate matters in scanning electron microscopy are loose pellets agglomeration together, adhesion of loose pellets to massive particles, and massive particles agglomeration together. For Na and K, the amounts of elements added have little effect on the adsorption of the sulfuric acid by ash particles. For Mg, Fe, and Ca, when the oxide is used as an additive, the adsorption capacity of ash samples to the vitriolic acid was enhanced and the agglomeration phenomenon of the ash granules was more remarkable with increasing elements amounts. In addition, the change of Mg has great impact on vitriolic acid adsorption and granules agglomeration. © 2022, Tsinghua University Press.

关键词： Adsorption

来源：评论

学校读者我要写书评

暂无评论

Novel Fast Predesign Methodology of Centrifugal Compressor Used for Pemfcs Based on 1d Loss Mechanism and Interpretable Machine Learning Models

SSRN

引用

SSRN 2024年

作者： Chen, Zhikai Sun, Jieshuai Chen, Ziying 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 significant challenge of balancing accuracy, time, and cost has consistently compelled designers to develop more efficient and economical predesign methods. To tackle this issue, a novel predesign method amalgamating one-dimensional (1D) loss model with gradient boosting decision tree (GBDT) model has been proposed. A high-precision 1D loss model was developed and experimentally tested for rapid performance assessment. Furthermore, two machine learning models, named Extreme Gradient Boosting (XGBoost) and Light Gradient Boosting Machine (LightGBM), were trained, and compared to construct surrogate models. Hyperparameter optimization was executed utilizing a Bayesian algorithm to identify the optimal hyperparameter set. Additionally, the Sobol sensitivity analysis and Shapley Additive Explanations (SHAP) based interpretability were used to explore the paramount factors affecting the model's outputs and the interactions among the sensitive parameters. The findings underscore that the blade outlet angle, impeller outlet diameter, impeller outlet width, inlet shroud diameter, and blade inlet angle(shroud) are the most five important parameters influencing the model's indexes. Some beneficial design guidelines are distilled from their feature importance and interactions. and The implement of new design yields powerful evidence for the developed prior knowledge with an increase of 2.5830% in isentropic efficiency and a reduction of 1.5202% in power consumption. © 2024, The Authors. All rights reserved.

关键词： Sensitivity analysis

来源：评论

学校读者我要写书评

暂无评论

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

引用

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

来源：评论

学校读者我要写书评

暂无评论

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

SSRN

引用

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

来源：评论

学校读者我要写书评

暂无评论

A large-scale power-to-H 2 -to-power system adopting hydrogen mixed gas turbine for wind accommodation: Process modeling, optimal dispatch and economic feasibility analysis

引用

International Journal of Hydrogen Energy 2025年 145卷 345-357页

作者： Yanxin Li Xiaoqu Han Yiming Zhang Nikolaos Skordoulias Xuanhua Guo Junjie Yan Sotirios Karellas Emmanuel Kakaras State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China Laboratory of Thermal Processes National Technical University of Athens Athens 15780 Greece Qingdao Huaru Energy Technology Company Limited Qingdao 266071 China Mitsubishi Hitachi Power Systems Europe GmbH Schifferstraße 80 Duisburg 47059 Germany

The high percentage of renewable energy penetration poses volatility and intermittency challenges, making it imperative to explore pathways for large-scale green hydrogen production and utilization. In the present work, a novel power-to-H 2 -to-power (PtH2tP) system is proposed for onshore wind accommodation, incorporating hydrogen mixed gas turbines (HMGTs). An innovative methodology integrating economic and carbon emissions assessment with optimal dispatch is developed, in which the HMGT off-design operational characteristics and policy compensation for green hydrogen are considered. A case study in China demonstrates the feasibility of the PtH2tP system in achieving flexible energy conversion and hydrogen self-sufficiency. Particularly, a levelized cost of electricity of 0.0537 €/kWh and carbon emissions of 0.29 kg CO 2 eq/kWh are observed. The fuel consumption of HMGTs and purchased grid electricity are significant contributors to carbon emissions. A comprehensive sensitivity analysis indicates an optimal hydrogen substitution ratio of 31% as the threshold for balancing economics and environmental benefits.

关键词： Windmill

来源：评论

学校读者我要写书评

暂无评论

Proposal design and thermodynamic analysis on a novel coal-based power generation system integrated with CO2 capture

Proposal design and thermodynamic analysis on a novel coal-b...

引用

Electrical engineering and Mechatronics Technology (ICEEMT), IEEE International Conference on

作者： Guobin Gao Ruiqi Mu Yali Yang Lei Yan Jun Gao Ming Liu Guoneng Jinjie Energy Co. Ltd Yulin China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an China

To enhance the energy efficiency and decrease the carbon emissions, a novel coal-based power generation system integrated with CO 2 capture is proposed in this study. The S-CO 2 cycle is integrated to recover the waster heat of system effectively. The heat transfer processes are well matched, and the irreversibility of heat exchangers in the system is reduced by splitting working medium appropriately. The system simulation and thermodynamic analysis models are developed. The energy and exergy efficiency of system are 51.32% and 50.07%, respectively. The system efficiency increases with the increase of the coal water slurry concentration (CWSC) and the decrease of the gasification temperature. When the CWSC is 35% and gasification temperature is 500 °C, the exergy efficiency of system reaches 51.74% and 50.59%, respectively.

关键词：

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：