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Numerical investigation for the suitable choice of bubble diameter correlation for EMMS/bubbling drag model

Chinese Journal of Chemical Engineering 2022年第7期35卷 254-270页

作者： Nouman Ahmad jianqiang deng Muhammad Adnan Shaanxi Key Laboratory of Energy Chemical Process Intensification Xi’an 710049China School of Chemical Engineering and Technology Xi’an Jiaotong UniversityXi’an 710049China

Mesoscale bubbles exist inherently in bubbling fluidized beds and hence should be considered in the constitutive modeling of the drag *** energy minimization multiscale bubbling(EMMS/bubbling)drag model takes the effects of mesoscale structures(i.e.,bubbles)into the modeling of drag coefficient and thus improves the coarse-grid simulation of bubbling and turbulent fluidized ***,its dependence on the bubble diameter correlation has not been thoroughly *** hydrodynamic disparity between homogeneous and heterogeneous fluidization is accounted for by the heterogeneity index,H_(d),which can be affected by choice of bubble diameter *** this choice of bubble diameter correlation influences the model prediction calls for further fundamental *** article incorporated seven different bubble diameter correlations into EMMS/bubbling drag model and studied their effects on H_(d).The performance of these correlations has been compared with the correlation used previously by EMMS/bubbling drag *** found that some of the correlations predicted lower Hd by order of a magnitude than the correlation used by the original EMMS/bubbling *** on such analysis,we proposed a modification in the EMMS drag model for bubbling and turbulent fluidized beds.A computational fluid dynamics(CFD)simulation using two-fluid model with the modified EMMS/bubbling drag model was performed for two bubbling and one turbulent fluidized *** distribution,time averaged solid concentration and axial solid concentration profiles were studied and compared with the previous version of the EMMS/bubbling drag model and experimental *** found that the right choice of bubble diameter correlations can significantly improve the results for CFD simulations.

关键词： Mesoscale Bubbles Energy minimization multiscale(EMMS) Heterogeneity index Bubbling fluidized bed

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Integration of energy recovery network including recycling residual pressure energy with pinch technology

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Chinese Journal of Chemical Engineering 2017年第4期25卷 453-462页

作者： jianqiang deng Zheng Cao Dongbo Zhang Xiao Feng School of Chemical Engineering and Technology Xi'an Jiaotong University Shaanxi Coal and Chemical Technology Institute Co. Ltd

Work exchange is a promising innovative technology in recovering residual pressure energy. However, at the systematic level, the comprehensive utilization of different energy resources in an energy system has become an issue of concern. In this work, a systematic approach is proposed, one that successively integrates heat, work and adjusts operation parameters. A detailed procedure for building a heat-work coupling transfer network is provided. The synthesis mainly consists of constructing a work exchange sub-network with pinch analysis based on positive displacement type work exchangers. Simultaneously, another kind of sub-network based on turbine-type work exchangers is built as a schematic comparison. The influence of applying a positive displacement work exchanger on the system is investigated. Finally, as a case study, a renovation design of a typical rectisol process in the coal-water slurry gasification section of an ammonia plant is presented. The results show that the added work exchanger has little impact on the existing heat exchange sub-network. Moreover,extra pressure energy is recovered by coupling the transfer network. It is concluded that the heat-work systematic design is a promising and powerful method to use energy more efficiently.

关键词： matching gasification successively slurry constructing exchanger recycling turbine powerful innovative

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Performance Improvement of Two-Phase Steam Ejector based on CFD Techniques,Response Surface Methodology and Genetic Algorithm

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Journal of Thermal Science 2024年第2期33卷 675-695页

作者： ZHANG Hao ZHAO Hongxia ZHANG Xiuao ZENG Hongxuan deng jianqiang School of Energy and Power Engineering Shandong UniversityJi’nan250061China School of Chemical Engineering and Technology Xi’an Jiaotong UniversityXi’an710049China

The steam ejector is a crucial component in the waste heat recovery *** performance determines the amount of recovered heat and system ***,poor ejector performance has always been the main bottleneck for system ***,this study proposes an optimization methodology to improve the steam ejector's performance by utilizing computational fluid dynamics(CFD) techniques,response surface methodology(RSM),and genetic algorithm(GA).Firstly,a homogeneous equilibrium model(HEM) was established to simulate the two-phase flow in the steam ***,the orthogonal test was presented to the screening of the key decision variables that have a significant impact on the entrainment ratio(ER).Next,the RSM was used to fit a response surface regression model(RSRM).Meanwhile,the effect of the interaction of geometric parameters on the performance of the steam ejector was ***,GA was employed to solve the RSRM's global optimal ER *** results show that the RSRM exhibits a good fit for ER(R^(2)=0.997).After RSM and GA optimization,the maximum ejector efficiency is 27.94%,which is 48.38% higher than the initial ejector of 18.83%.Furthermore,the optimized ejector efficiency is increased by 46.4% on average under off-design ***,the results reveal that the combination of CFD,RSM,and GA presents excellent reliability and feasibility in the optimization design of a two-phase steam ejector.

关键词： two-phase steam ejector optimization methodology CFD techniques response surface methodology genetic algorithm homogeneous equilibrium model

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Energy dissipation mechanism and ballistic characteristic optimization in foam sandwich panels against spherical projectile impact

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Defence Technology（防务技术） 2024年第5期35卷 108-122页

作者： jianqiang deng Tao Liu Liming Chen Xin Pan Jingzhe Wang Shaowei Zhu Weiguo Li College of Aerospace Engineering Chongqing UniversityChongqing 400030China State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing 400030China Chongqing Key Laboratory of Heterogeneous Material Mechanics Chongqing UniversityChongqing 400030China State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China

This study systematically examines the energy dissipation mechanisms and ballistic characteristics of foam sandwich panels(FSP)under high-velocity impact using the explicit non-linear finite element *** on the geometric topology of the FSP system,three FSP configurations with the same areal density are derived,namely multi-layer,gradient core and asymmetric face sheet,and three key structural parameters are identified:core thickness(t_(c)),face sheet thickness(t_(f))and overlap face/core number(n_(o)).The ballistic performance of the FSP system is comprehensively evaluated in terms of the ballistic limit velocity(BLV),deformation modes,energy dissipation mechanism,and specific penetration energy(SPE).The results show that the FSP system exhibits a significant configuration dependence,whose ballistic performance ranking is:asymmetric face sheet>gradient core>*** mass distribution of the top and bottom face sheets plays a critical role in the ballistic resistance of the FSP *** BLV and SPE increase with tf,while the raising tcor noleads to an increase in BLV but a decrease in ***,a face-core synchronous enhancement mechanism is discovered by the energy dissipation analysis,based on which the ballistic optimization procedure is also conducted and a design chart is *** study shed light on the anti-penetration mechanism of the FSP system and might provide a theoretical basis for its engineering application.

关键词： Sandwich panel Numerical simulation Ballistic resistance Specific penetration energy Energy analysis

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Autopsy results from a COVID-19 patient treated in a tropical area,and a review of the epidemiological history

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Forensic Sciences Research 2022年第3期7卷 560-565页

作者： Jie Cai Bo Wang Tao Song Peng Zhang Ren Long Xiaoran Liu jianqiang deng Jianhua Chen Department of Forensic Medicine Hainan Tropical Forensic Engineering Research CenterHainan Medical UniversityHaikouChina Key Laboratory of Emergency and Trauma of Ministry of Education Emergency and Trauma CollegeHainan Medical UniversityHaikouChina

Since the start of the COVID-19 pandemic,there has been an urgent need to produce accurate and sensitive ***,there have been instances where a positive nucleic acid test turns negative after treatment,and then positive *** case report describes such an instance from the tropical region of Hainan,*** patient was a 61-year-old female who went to Hainan on vacation from Wuhan during the COVID-19 pandemic in *** appeared 9 d after arriving in Hainan,and it was confirmed that the nucleic acid test was positive after 4 *** condition declined rapidly,her heart stopped beating,and she was admitted in a coma to the *** treatment,the SARS-CoV-2 virus nucleic acid test of several nasopharyngeal swabs were negative,and tests on whole blood,anal swabs,and urine were also ***,however,nucleic acid tests on a lower respiratory tract sputum swab and lower respiratory tract lavage fluid were *** autopsy examination was carried out 12h after her death,and multi-organ secretions were extracted for nucleic acid *** SARS-CoV-2 virus nucleic acid was only detected in the swabs from the end of the bronchus,which was confirmed by the visualization of the coronavirus by electron *** confirmed that the damage was mainly concentrated in the lungs and immune organs and tissues throughout the *** indicated that none of the people she came into contact with after arriving in Hainan,including close contacts,were *** is in sharp contrast to the highly contagious virus in Wuhan in the temperate zone during the same *** case report indicates:(1)The high temperatures in tropical areas may have an impact on the spread and harm of COVID-19,and(2)The reason why nucleic acid testing for COVID-19 was initially negative and then positive after treatment may be related to the survival of the SARS-CoV-2 virus in deep lung tissues.

关键词： Forensic sciences forensic pathology COVID-19 SARS-CoV-2 autopsy tropical area epidemiological history

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跨临界CO_2引射制冷循环临界背压分析

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西安交通大学学报 2012年第9期46卷 66-70页

作者：王菲邓建强西安交通大学能源与动力工程学院西安710049

为了优化设计或控制引射系统的性能,建立了跨临界CO2引射制冷循环中引射器性能的设定背压模型,定义引射器临界背压为忽略引射器出口动能时的引射器迭代背压,分析了引射器背压和出口速度对系统性能的影响.结果表明:当引射器背压低于临界... 详细信息

为了优化设计或控制引射系统的性能,建立了跨临界CO2引射制冷循环中引射器性能的设定背压模型,定义引射器临界背压为忽略引射器出口动能时的引射器迭代背压,分析了引射器背压和出口速度对系统性能的影响.结果表明:当引射器背压低于临界值时,引射系数保持不变,且在不同系统高压侧压力下均成立;系统性能系数(COP)随着背压升高而增大,在系统状态可控的情况下引射器背压应尽量靠近临界值.同时,不同背压下COP随高压侧压力变化的趋势相同,背压作为设计或控制参数不会影响高压侧压力的优化.引射器出口动能会因流动摩擦和冲击而转化成热量并造成系统的热力学损失,背压选取不当会造成较大的引射器出口速度,且随着背压降低,出口速度增大,随着系统高压侧压力升高,出口速度先急剧降低,再缓慢变化.

关键词：二氧化碳跨临界循环引射器临界背压

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A brief review of forensically important flesh flies (Diptera: Sarcophagidae)

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Forensic Sciences Research 2018年第1期3卷 16-26页

作者： Lipin Ren Yanjie Shang Wei Chen Fanming Meng Jifeng Cai Guanghui Zhu Lushi Chen Yong Wang jianqiang deng Yadong Guo Department of Forensic Science School of Basic Medical SciencesCentral South UniversityChangshaChina Department of Forensic Medicine Shantou University Medical CollegeShantouChina Department of Forensic Medicine Guizhou Police Officer Vocational CollegeGuiyangChina Department of Forensic Medicine Hainan Medical UniversityHaikouChina

Forensic entomology could provide valuable data for the minimum postmortem interval (PMImin) estimation and other relevant information,such as causes and circumstances of *** representatives of flesh flies are one of the dominant necrophagous insects during early stages of decomposition,demonstrating unique biological characteristics compared with other necrophagous ***,they lead to global health concerns as carriers of various pathogenic micro-organisms,and dominantly result in the traumatic ***,sarcophagid flies are considered important in decomposition processes for PMImin ***,the utility of sarcophagid flies has been seriously hampered by limited ecological,biological and taxonomic knowledge of *** aim of this paper is to provide a brief review on the species,distribution and biological habit of forensically important sarcophagid *** addition,the relation between traumatic myiasis and flesh flies,molecular identification methods and developmental pattern of flesh flies are summarized.

关键词： Forensic science forensic entomology sarcophagid flies decomposition biology distribution

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化工过程功量交换回收效率理论

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化工学报 2011年第11期62卷 3017-3023页

作者：邓建强马丽冯霄西安交通大学能源与动力工程学院陕西西安710049

化工过程中气体流股经常具有流量大、压力高的特点,因而有功量回收应用潜力,而气体可压缩的特点给功量回收效率分析带来困难。针对功量交换器往复式和离心式两种机械结构,分别对气体-气体(气气)功量交换推导了功量回收效率表达式,并通... 详细信息

化工过程中气体流股经常具有流量大、压力高的特点,因而有功量回收应用潜力,而气体可压缩的特点给功量回收效率分析带来困难。针对功量交换器往复式和离心式两种机械结构,分别对气体-气体(气气)功量交换推导了功量回收效率表达式,并通过合理假设进行简化,对比分析了两种结构下功量回收效率理论值。并对两种结构形式下不同物流相态匹配的功量回收效率计算式进行了表述,针对往复式结构能够突出物流相态对气体功量回收效率的特殊影响,对往复式结构下不同物流相态匹配下的功量回收效率进行了比较和分析。研究表明,功量交换结构对气体功量回收效率有重要影响,往复式结构功量回收效率为随压比增大而减小的幂函数关系,而离心式结构功量回收效率还与高低压流股初始体积流量比有关。离心式结构能够实现比往复式结构大的功量回收效率和高于高压流股初始压力的目标压力。在同样压比下,往复式结构中液液功量交换具有最高的功量回收效率(理想值为100%),气液功量交换和液气功量交换值依次减小,而气气功量回收效率最低,而离心式结构同样还与高低压初始体积流量比有关。

关键词：功量交换器往复机械离心机械功量回收效率

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地质封存中CO_2泄漏的非稳态扩散数值模拟研究

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西安交通大学学报 2012年第9期46卷 102-107页

作者：马登龙邓建强张早校西安交通大学多相流国家重点实验室西安710049 西安交通大学能源与动力工程学院西安710049

针对碳捕集与封存技术中泄漏监测的难点,利用数值模拟方法研究了地质封存中CO2泄漏的非稳态扩散,以及不同的垂直风廓线形式、大气、地形等因素对非稳态扩散模拟结果的影响,探索了地质封存中CO2泄漏扩散的分布规律.研究结果表明:不同风... 详细信息

针对碳捕集与封存技术中泄漏监测的难点,利用数值模拟方法研究了地质封存中CO2泄漏的非稳态扩散,以及不同的垂直风廓线形式、大气、地形等因素对非稳态扩散模拟结果的影响,探索了地质封存中CO2泄漏扩散的分布规律.研究结果表明:不同风廓线下CO2泄漏的扩散规律基本一致,仅在垂直方向上CO2的体积分数略有差异;大气层结不稳定程度越高,越有利于泄漏气体的扩散;风速越大,扩散达到稳定所需要的时间越短,稳定的CO2的体积分数越小;大气温度越高,同一高度上稳定的CO2体积分数越大,越有利于泄漏气体的垂直扩散;地表面粗糙度越大,越有利于垂直湍流波动的形成,当水平扩散减慢时,CO2达到稳定所需要的时间延长.

关键词：碳捕集与封存地质封存非稳态扩散

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跨临界CO_(2)快速膨胀过程中非平衡冷凝和闪蒸机理的数值研究

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化工学报 2022年第7期73卷 2912-2923页

作者：李亚飞邓建强何阳西安交通大学化学工程与技术学院陕西西安710049 陕西省能源化工过程强化重点实验室陕西西安710049

跨临界CO_(2)在高速膨胀时,压力和温度剧烈下降,会发生非平衡相变。其中在天然气超声速分离设备和超临界CO_(2)离心压缩机中CO_(2)会发生非平衡冷凝相变;在引射膨胀制冷系统中,跨临界CO_(2)在引射器主动喷嘴中发生非平衡闪蒸相变。为解... 详细信息

跨临界CO_(2)在高速膨胀时,压力和温度剧烈下降,会发生非平衡相变。其中在天然气超声速分离设备和超临界CO_(2)离心压缩机中CO_(2)会发生非平衡冷凝相变;在引射膨胀制冷系统中,跨临界CO_(2)在引射器主动喷嘴中发生非平衡闪蒸相变。为解决跨临界CO_(2)在膨胀过程中物性变化剧烈,非平衡相变模拟困难的问题,构建了新型非平衡相变CFD模型,以研究跨临界CO_(2)在超声速缩放喷嘴中的非平衡冷凝和非平衡闪蒸的相变过程和膨胀机理,模型耦合了温度驱动的蒸发-冷凝相变机制和压力驱动的空化-冷凝相变机制,并用文献中的试验结果验证了模型的准确性。研究结果表明,在冷凝相变过程中,由压力驱动的冷凝传质具有主要影响,压力驱动的冷凝传质主要存在于喷嘴喉部与内流区域,温度驱动的冷凝传质主要存在于喷嘴渐扩段壁面。冷凝传质速率随着进口压力的增加和进口温度的降低而增加,从而使冷凝的非平衡程度和喷嘴内的干度降低,喷嘴渐扩段内达到声速的位置也相应延后。在闪蒸相变过程中,由温度驱动的蒸发传质占据主导,蒸发相变主要发生在喷嘴喉部附近,空化相变主要发生在喷嘴渐扩段,两相CO_(2)在喷嘴的渐扩段达到声速。随着喷嘴进口压力的增加和进口温度的降低,闪蒸的非平衡程度增加,使喷嘴内的干度减小。本研究有助于厘清跨临界CO_(2)快速膨胀中的非平衡闪蒸和冷凝相变机理,并为跨临界CO_(2)膨胀设备的分析和优化设计提供参考。

关键词：二氧化碳闪蒸冷凝超声速喷嘴气液两相流计算流体力学

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