检索结果-南通市图书馆

空气标准等温加热修正Brayton循环:(2)多目标优化

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

热力透平 2024年第1期53卷 6-10,25页

作者：危思戈延林陈林根冯辉君武汉工程大学热科学与动力工程研究所武汉430205 湖北省绿色化工装备工程技术研究中心武汉430205 武汉工程大学机电工程学院武汉430205

基于第1部分对循环功率和效率特性的研究,进一步以效率、生态学函数、功率和功率密度为优化目标,以压缩比为优化变量,利用NSGA-Ⅱ算法对内可逆空气标准等温加热修正Brayton循环进行不同目标组合的单、双、三和四目标优化,并利用偏差指数... 详细信息

基于第1部分对循环功率和效率特性的研究,进一步以效率、生态学函数、功率和功率密度为优化目标,以压缩比为优化变量,利用NSGA-Ⅱ算法对内可逆空气标准等温加热修正Brayton循环进行不同目标组合的单、双、三和四目标优化,并利用偏差指数对3种决策方式的优化结果进行分析对比,从而寻找最优解集。结果表明三目标优化中偏差指数最小,为0.129 2。故多目标优化能更有效地找到最优解集。研究成果可为Brayton热机循环的优化设计提供一定参考。

关键词：内可逆循环空气标准等温加热修正Brayton循环多目标优化 NSGA-Ⅱ算法决策方法

Pre-reduction of WO_(3)-Co_(3)O_(4)by H_(2)-C_(2)H_4 in a fluidized bed

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2024年第2期66卷 273-284页

作者： huijun Shang Hengli Li Weijun Li feng Pan Zhan Du State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of Sciences(CAS)Beijing 100190China College of Chemical Engineering Nanjing Technology UniversityNanjing 211816China School of Chemistry and Chemical Engineering Shihezi UniversityShihezi 832003China College of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China Chinalco Environmental Protection and Energy Conservation Group Co. Ltd.Xiong’an 071700China

In order to avoid the formation ofηphase(W_(6)Co_(6)C or W_(3)Co_(3)C)that adversely affects the sintering process and its products in the preparation process of ultra-fine WC-Co powder,a technical route of prereduction of WO_(3)-Co_(3)O_(4)to WO_(2)-Co and then deep reduction carbonization to WC-Co powder has been *** study mainly investigates the influence of gas partial pressure on the pre-reduction process of WO_(3)-Co_(3)O_(4)under a mixed atmosphere of H_(2)-C_(2)H_(4)-Ar at 600℃and establishes the kinetic equations of pre-reduction and carbon *** results indicate that increasing the partial pressure of hydrogen is conducive to the rapid and complete conversion of WO_(3) to WO_(2).High carbon content can be generated by the deposition of C_(2)H_(4),and it hinders the diffusion of the reducing gas;WO_(3)still cannot be completely reduced to WO_(2)as the partial pressure of C_(2)H_(4) increases to 60%.For the carbon evolution of C_(2)H_(4),the carbon amount is positively related to the H_(2)partial pressure,but it shows the highest amount and evolution rate when the ethylene partial pressure is 20%.Based on the reduction rate curves of WO_(3) and carbon evolution rate curves of C_(2)H_(4),the rate equations of pre-reduction and carbon evolution of WO_(3)-Co_(3)O_(4)system at 600℃are *** pre-reduction reaction belongs to the first-order reaction,and its equation is expressed as follows:r=-(dw_(WO_(3)))/dt=(9±0.15)×10^(-2)×P_(H_(2))^(0.44)P_(C_(2)H_(4))&(0.57)The carbon deposition rate equation of C_(2)H_(4) can be expressed as follows:r=-(dc_C)/dt=r_f-r_b≌7.35×10^(-2)×P_(C_(2)H_(4))^(0.31)

关键词： Fluidization WO_(3)-Co_(3)O_(4) Reduction Carbon deposition Rate equation

NCAD v1.0: a database for non-coding variant annotation and interpretation

在线全文

学校读者我要写书评

暂无评论

Journal of Genetics and Genomics 2024年第2期51卷 230-242页

作者： Xiaoshu feng Sihan Liu Ke Li fengxiao Bu huijun Yuan Institute of Rare Diseases West China HospitalSichuan UniversityChengduSichuan 610044China

The application of whole genome sequencing is expanding in clinical diagnostics across various genetic disorders, and the significance of non-coding variants in penetrant diseases is increasingly being demonstrated. Therefore, it is urgent to improve the diagnostic yield by exploring the pathogenic mechanisms of variants in non-coding regions. However, the interpretation of non-coding variants remains a significant challenge, due to the complex functional regulatory mechanisms of non-coding regions and the current limitations of available databases and tools. Hence, we develop the non-coding variant annotation database (NCAD, http://***/), encompassing comprehensive insights into 665,679,194 variants, regulatory elements, and element interaction details. Integrating data from 96 sources, spanning both GRCh37 and GRCh38 versions, NCAD v1.0 provides vital information to support the genetic diagnosis of non-coding variants, including allele frequencies of 12 diverse populations, with a particular focus on the population frequency information for 230,235,698 variants in 20,964 Chinese individuals. Moreover, it offers prediction scores for variant functionality, five categories of regulatory elements, and four types of non-coding RNAs. With its rich data and comprehensive coverage, NCAD serves as a valuable platform, empowering researchers and clinicians with profound insights into non-coding regulatory mechanisms while facilitating the interpretation of non-coding variants.

关键词： Non-coding variants Annotation Variant interpretation Database

Constructal entransy dissipation rate minimization for X-shaped vascular networks

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2019年第12期62卷 2195-2203页

作者： feng huijun CHEN LinGen XIE ZhiHui Institute of Thermal Science and Power Engineering Wuhan Institute of TechnologyWuhan 430205China School of Mechanical&Electrical Engineering Wuhan Institute of TechnologyWuhan 430205China College of Power Engineering Naval University of EngineeringWuhan 430033.China

Combining with entransy theory, constructal designs of the X-shaped vascular networks(XSVNs) are implemented with fixed total tube volumes of the XSVNs. The entransy dissipation rates(EDRs) of the XSVNs are minimized, and the optimal constructs of the XSVNs are derived. Comparison of the optimal constructs of the XSVNs with two optimization objectives(EDR minimization and entropy generation rate(EGR) minimization) is conducted. It is found that when the dimensionless mass flow rate(DMFR) is small, the optimal diameter ratio of the elemental XSVN derived by EDR minimization is different from that derived by EGR minimization. For the multilevel XSVN, when the DMFR is 100, compared the XSVN with the corresponding H-shaped vascular network(HSVN), the dimensionless EDRs of the elemental, second and fourth order XSVNs are reduced by 26.39%, 15.34% and 9.81%, respectively. Compared with the entransy dissipation number(EDN) of the second order XSVN before angle optimization, the EDN after optimization is reduced by 26.15%, which illustrates that it is significant to conduct angle optimization of the XSVN. Entransy theory is applied into the constructal design of the vasculature with heat transfer and fluid flow in this paper, which provides new directions for the vasculature designs.

关键词： constructal theory entransy theory X-shaped vascular networks generalized thermodynamic optimization

Constructal optimization for H-shaped multi-scale heat exchanger based on entransy theory

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2013年第2期56卷 299-307页

作者： feng huijun CHEN LinGen XIE ZhiHui SUN fengRui College of Power Engineering Naval University of Engineering

Analogizing with the definition of thermal efficiency of a heat exchanger,the entransy dissipation efficiency of a heat exchanger is defined as the ratio of dimensionless entransy dissipation rate to dimensionless pumping power of the heat *** the constraints of the total tube volume and total tube surface area of the heat exchanger,the constructal optimization of an H-shaped multi-scale heat exchanger is carried out by taking entransy dissipation efficiency maximization as optimization objective,and the optimal construct of the H-shaped multi-scale heat exchanger with maximum entransy dissipation efficiency is *** results show that for the specified total tube volume of the heat exchanger,the optimal constructs of the first order T-shaped heat exchanger based on the maximizations of the thermal efficiency and entransy dissipation efficiency are obviously different with the lower mass flow rates of the cold and hot *** the H-shaped multi-scale heat exchanger,the entransy dissipation efficiency decreases with the increase in mass flow rate when the heat exchanger order is fixed;for the specified dimensionless mass flow rate M(M<32.9),the entransy dissipation efficiency decreases with the increase in the heat exchanger *** performance of the multi-scale heat exchanger is obviously improved compared with that of the single-scale heat ***,the heat exchanger subjected to the total tube surface area constraint is also discussed in the *** optimization results obtained in this paper can provide a great compromise between the heat transfer and flow performances of the heat exchanger,provide some guidelines for the optimal designs of heat exchangers,and also enrich the connotation of entransy theory.

关键词：构形优化多尺度换热器热交换器基础质量流率流动性能耗散率

A multi-objective study on the constructal design of non-uniform heat generating disc cooled by radial-and dendritic-pattern cooling channels

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2021年第4期64卷 729-744页

作者： CHEN Chen YOU Jiang feng huijun CHEN LinGen Institute of Thermal Science and Power Engineering Wuhan Institute of TechnologyWuhan 430205China School of Mechanical&Electrical Engineering Wuhan Institute of TechnologyWuhan 430205China §School of Optical Information and Energy Engineering Wuhan Institute of TechnologyWuhan 430205China College of Power Engineering Naval University of EngineeringWuhan 430033China

A three-dimensional disc model with non-uniform heat generating is built.A series of cooling channels are inserted to cool this disc which is strewn in a hierarchical *** reveal thermal and flow characteristics,a composite objective function comprised of the maximum temperature difference(MTD)and pumping power is *** deployment pattern of cooling channels contains two cases,i.e.,the radial-pattern and *** capitalizing on constructal design method together with finite element method,the diameter of radial-pattern cooling channels is optimized in the first ***,the diameter,angle coefficient and length coefficient of dendritic-pattern cooling channels are three degrees-of-freedom to be stepwise optimized at different heat generating ***,NSGA-II algorithm is introduced into the multiobjective *** obtaining its Pareto optimal solution set,Topsis method is invoked to yield the optimal solutions under given weighted *** heat generation over the entire body and the volume ratio of cooling channels operate as the primary *** on these premises,constructal design will be stepwise performed by varying three *** obtained results state that more heating components or devices should be installed as close to the cooling water inlet as *** can further reduce MTD at the same cost of pumping power,thereby improve thermal and flow performance and prolong the lifespan of *** optimized with two degrees-of-freedom,the MTD is reduced by 18.6%compared with the counterpart obtained from single degree-of-freedom optimization,while the pumping power is increased by 59.8%.As optimized with three degrees-of-freedom,the MTD is decreased by 6.2%compared with the counterpart from two degrees-of-freedom optimization,while the pumping power is increased by 3.0%.It is manifest that when two sub-objectives form a composite objective,the performance improvement of one sub-

关键词： constructal law non-uniform heat generating disc heat convection cooling channels multi-objective optimization generalized thermodynamic optimization

“Volume-point” heat conduction constructal optimization based on entransy dissipation rate minimization with three-dimensional cylindrical element and rectangular and triangular elements on microscale and nanoscale

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2012年第3期55卷 779-794页

作者： feng huijun CHEN LinGen SUN fengRui College of Naval Architecture and Power Naval University of EngineeringWuhan 430033China

Based on constructal theory,the constructs of three "volume-point" heat conduction models with three-dimensional cylindrical element and rectangular and triangular elements on microscale and nanoscale are optimized by taking minimum entransy dissipation rate as optimization *** optimal constructs of the three "volume-point" heat conduction models with minimum dimensionless equivalent thermal resistance are *** results show that the optimal constructs of the three-dimensional cylindrical assembly based on the minimizations of dimensionless equivalent thermal resistance and dimensionless maximum thermal resistance are different,which is obviously different from the comparison between those of the corresponding two-dimensional rectangular assembly based on the minimizations of these two *** optimal constructs based on rectangular and triangular elements on microscale and nanoscale when the size effect takes effect are obviously different from those when the size effect does not take *** the thermal current density in the high conductivity channel of the rectangular and triangular second order assemblies are not linear with the length,the optimal constructs of these assemblies based on the minimization of entransy dissipation rate are different from those based on the minimization of maximum temperature *** dimensionless equivalent thermal resistance defined based on entransy dissipation rate reflects the average heat transfer performance of the *** studies on "volume-point" heat conduction constructal problems at three-dimensional conditions and microscale and nanoscale by taking minimum entransy dissipation rate as optimization objective extend the application range of the entransy dissipation extremum principle.

关键词：构形优化耗散率三角形纳米级长方形元素微型圆柱

Constructal entransy dissipation rate minimization for helm-shaped fin with inner heat sources

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2015年第6期58卷 1084-1090页

作者： feng huijun CHEN LinGen XIE ZhiHui SUN fengRui Institute of Thermal Science and Power Engineering Naval University of Engineering Military Key Laboratory for Naval Ship Power Engineering Naval University of Engineering College of Power Engineering Naval University of Engineering

A model of three-dimensional helm-shaped body composed of a helm-shaped fin and inner heat sources is built in this paper. For the specified volumes of the body, fin and heat source, the constructal optimizations of the body with single and multiple inner heat sources are implemented. The entransy-dissipation-rate-based equivalent thermal resistance(ETR) is minimized in the optimizations. It shows that for the helm-shaped body with multiple inner heat sources, there exist an optimal ratio of the heat source distance to the radius of the extended fin and a twice optimal radius ratio of the centre fin to the extended fin which lead to the double minimum dimensionless ETR. Comparing the optimal result of the body with helm-shaped fin with that with annular fin, the radius of the centre fin and the distance between the heat source and the center of the body are decreased, and the ETR is decreased by 9.57%. Essentially, the temperature gradient field of the helm-shaped body is more homogenous, and its global heat transfer performance is improved.

关键词：内部热源耗散率鳍片构形舵温度梯度场半径比传热性能

Optimal Performance Characteristics of Subcritical Simple Irreversible Organic Rankine Cycle

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2018年第6期27卷 555-562页

作者： CHEN Weijian feng huijun CHEN Lingen XIA Shaojun Institute of Thermal Science and Power Engineering Naval University of Engineering Military Key Laboratory for Naval Ship Power Engineering Naval University of Engineering College of Power Engineering Naval University of Engineering

Based on the theory of finite time thermodynamics, a subcritical simple irreversible organic Rankine cycle(SSIORC) model considering heat transfer loss and internal irreversible losses is established in this paper. The total heat transfer surface area is taken as a constraint, and R245fa is adopted as working fluid of the cycle in the performance optimization. The evaporator heat transfer surface area and mass flow rate of the working fluid are optimized to obtain the maximum power output and thermal efficiency of the SSIORC, respectively. In addition, the influences of the internal irreversibilities on the optimal performances are also investigated. The results show that when the evaporator heat transfer surface area is varied, the relationship between power output and thermal efficiency is a loop-shaped curve, and there exist maximum power output and thermal efficiency points, respectively. However, the two maximum points are very close to each other. When the mass flow rate of the working fluid is varied, the relationship between power output and thermal efficiency is a parabolic-like curve. With the decreases of expander and pump irreversible losses, the performances of the irreversible SSORC are close to those of the endoreversible SSORC with the only loss of heat transfer loss.

关键词：不可逆表演周期器官有限时间热力学特征工作液体热转移