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| 1 | Influence of interannual variability of Antarctic oscillation on mei-yu along the Yangtze and Huaihe River valley and its importance to prediction显示文摘Both correlation analysis and case study indi-cate that Antarctic oscillation (AAO) is closely related withsummer rainfall in eastern China. When AAO is stronger inboreal spring, especially in May, there is more mei-yu rain-fall in summer with a longer period along the Yangtze andHuaihe River valley. In contrast, there is less rainfall with ashorter period corresponding to a weaker AAO. Besides, ananomalous AAO changes the position and intensity of severalcirculation systems, which are important to summer rainfallalong the Yangtze and Huaihe River valley. Furthermore, theAntarctic sea ice is negatively correlated with the intensity ofAAO with a 6-month leading time. The result in this studyprovides a new method for the prediction of mei-yu. | GAO Hui~(1,2), XUE Feng~1 WANG Huijun~1 1. Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China 2. Department of Atmospheric Sciences, Nanjing Institute of Meteorology, Nanjing 210044. China | 2003 | Chinese Science Bulletin2003，48，S2： | 34 |
| 2 | Constructal design progress for eight types of heat sinks显示文摘This review paper summarizes constructal design progress performed by the authors for eight types of heat sinks with ten performance indexes being taken as the optimization objectives,respectively,by combining the methods of theoretical analysis and numerical calculation.The eight types of heat sinks are uniform height rectangular fin heat sink,non-uniform height rectangular fin heat sink,inline cylindrical pin-fin heat sink(ICPHS),plate single-row pin fin heat sink(PSRPHS),plate inline pin fin heat sink(PIPHS),plate staggered pin fin heat sink(PSPHS),single-layered microchannel heat sink(SLMCHS)with rectangular cross sections and double-layered microchannel heat sink(DLMCHS)with rectangular cross sections,respectively.And the ten performance indexes are heat transfer rate maximization,maximum thermal resistance minimization,minimization of equivalent thermal resistance which is defined based on the entransy dissipation rate(equivalent thermal resistance for short),field synergy number maximization,entropy generation rate minimization,operation cost minimization,thermo-economic function value minimization,pressure drop minimization,enhanced heat transfer factor maximization and efficiency evaluation criterion number maximization,respectively.The optimal constructs of the eight types of heat sinks with different constraints and based on the different optimization objectives are compared with each other.The results indicated that the optimal constructs mostly are different based on different optimization objectives under the same boundary condition.The optimization objective should be suitable chosen based on the focus when the constructal design for one heat sink is performed.The results obtained herein have some important theoretical significances and application values,and can provide scientific bases and theoretical guidelines for the thermal design of real heat sinks and their applications. | CHEN LinGen YANG AiBo FENG HuiJun GE YanLin XIA ShaoJun | 2020 | Science China(Technological Sciences)2020，63，6： | 25 |
| 3 | “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显示文摘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 objective.The optimal constructs of the three 'volume-point' heat conduction models with minimum dimensionless equivalent thermal resistance are obtained.The 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 objectives.The 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 effect.Because 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 difference.The dimensionless equivalent thermal resistance defined based on entransy dissipation rate reflects the average heat transfer performance of the construct.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. | FENG HuiJun CHEN LinGen SUN FengRui | 2012 | Science China(Technological Sciences)2012，55，3： | 20 |
| 4 | Constructal entransy dissipation rate minimization for leaf-like fins显示文摘Based on constructal theory,the constructs of the leaf-like fins are optimized by taking minimum entransy dissipation rate(for the fixed total thermal current,i.e.,the equivalent thermal resistance) as optimization objective.The optimal constructs of the leaf-like fins with minimum dimensionless equivalent thermal resistance are obtained.The results show that there exists an optimal elemental leaf-like fin number,which leads to an optimal global heat conduction performance of the first order leaf-like fin.The Biot number has little effects on the optimal elemental fin number,optimal ratios of length and width of the elemental and first order leaf-like fins;with the increase of the thermal conductivity ratio of the vein and blade,the optimal elemental fin number and optimal ratio of the length and width of the elemental leaf-like fin increase,and the optimal shape of the first order leaf-like fin becomes tubbier.The optimal construct based on entransy dissipation rate minimization is obviously different from that based on maximum temperature difference minimization.The dimensionless equivalent thermal resistance based on entransy dissipation rate minimization is reduced by 11.54% compared to that based on maximum temperature difference minimization,and the global heat conduction performance of the leaf-like fin is effectively improved.For the same volumes of the elemental and first order leaf-like fins,the minimum dimensionless equivalent thermal resistance of the first order of the leaf-like fin is reduced by 30.10% compared to that of the elemental leaf-like fin,and the global heat conduction performance of the first order leaf-like fin is obviously better than that of the elemental leaf-like fin.Essentially,this is because the temperature gradient field of the first order leaf-like fin based on entransy dissipation rate minimization is more homogenous than that of the elemental leaf-like fin.The dimensionless equivalent thermal resistance defined based on entransy dissipation rate reflects the average heat transfer performance of the leaf-like fin,and can provide some guidelines for the thermal design of the fins from the viewpoint of heat transfer optimization. | FENG HuiJun CHEN LinGen SUN FengRui | 2012 | Science China(Technological Sciences)2012，55，2： | 19 |
| 5 | Constructal entransy optimizations for insulation layer of steel rolling reheating furnace wall with convective and radiative boundary conditions显示文摘Based on the entransy dissipation extremum principle for thermal insulation process,the constructal optimizations for a plane insulation layer of the steel rolling reheating furnace wall with convective and radiative boundary conditions are carried out by taking the minimization of entransy dissipation rate as optimization objective.The optimal construct of the plane insulation layer is obtained.The results show that for the convective heat transfer boundary condition,the optimal constructs of the insulation layer obtained based on the minimizations of the entransy dissipation rate and heat loss rate are obviously different.Comparing the optimal construct obtained based on the minimization of the entransy dissipation rate with that based on the minimization of the heat loss rate,the entransy dissipation rate is reduced by 5.98%,which makes the global thermal insulation performance of the insulation layer improve.For the combined convective and radiative heat transfer boundary condition,compared the insulation layer having an increasing thickness with that having constant thickness and a decreasing thickness,the entransy dissipation rates are reduced by 16.59%and39.72%,respectively,and the global thermal insulation performance of the insulation layer is greatly improved.There exits an optimal constant coefficient a2;optwhich leads to the minimum dimensionless entransy dissipation rate of the insulation layer.The difference between the optimal constant coefficients a2;optobtained based on the minimizations of the entransy dissipation rate and the maximum temperature gradient of the insulation layer is small.This makes the corresponding thermal stress obtained based on the minimum dimensionless entransy dissipation rate also be small,and the global thermal insulation performance and thermal safety of the insulation layer are improved simultaneously.The results obtained can provide some guidelines for the optimal designs of the insulation layers. | Huijun Feng Lingen Chen Zhihui Xie Fengrui Sun | 2014 | Chinese Science Bulletin2014，59，20： | 19 |
| 6 | Constructal optimization for H-shaped multi-scale heat exchanger based on entransy theory显示文摘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 exchanger.For 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 obtained.The 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 fluids.For 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 order.The performance of the multi-scale heat exchanger is obviously improved compared with that of the single-scale heat exchanger.Moreover,the heat exchanger subjected to the total tube surface area constraint is also discussed in the paper.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. | FENG HuiJun CHEN LinGen XIE ZhiHui SUN FengRui | 2013 | Science China(Technological Sciences)2013，56，2： | 16 |
| 7 | Constructal entransy dissipation rate minimization for helm-shaped fin with inner heat sources显示文摘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. | FENG HuiJun CHEN LinGen XIE ZhiHui SUN FengRui | 2015 | Science China(Technological Sciences)2015，58，6： | 14 |
| 8 | Thermal insulation constructal optimization for steel rolling reheating furnace wall based on entransy dissipation extremum principle显示文摘Analogizing with the heat conduction process, the entransy dissipation extremum principle for thermal insulation process can be described as: for a fixed boundary heat flux (heat loss) with certain constraints, the thermal insulation process is optimized when the entransy dissipation is maximized (maximum average temperature difference), while for a fixed boundary temperature, the thermal insulation process is optimized when the entransy dissipation is minimized (minimum average heat loss rate). Based on the constructal theory, the constructal optimizations of a single plane and cylindrical insulation layers as well as multi-layer insulation layers of the steel rolling reheating furnace walls are carried out for the fixed boundary temperatures and by taking the minimization of entransy dissipation rate as optimization objective. The optimal constructs of these three kinds of insulation structures with distributed thicknesses are obtained. The results show that compared with the insulation layers with uniform thicknesses and the optimal constructs of the insulation layers obtained by minimum heat loss rate, the optimal constructs of the insulation layers obtained by minimum entransy dissipation rate are obviously different from those of the former two insulation layers; the optimal constructs of the insulation layers obtained by minimum entransy dissipation rate can effectively reduce the average heat loss rates of the insulation layers, and can help to improve their global thermal insulation performances. The entransy dissipation extremum principle is applied to the constructal optimizations of insulation systems, which will help to extend the application range of the entransy dissipation extremum principle. | FENG HuiJun CHEN LinGen XIE ZhiHui SUN FengRui | 2012 | Science China(Technological Sciences)2012，55，12： | 14 |
| 9 | Generalized constructal optimization for the secondary cooling process of slab continuous casting based on entransy theory显示文摘Based on constructal theory and entransy theory,a generalized constructal optimization of a solidification heat transfer process of slab continuous casting for a specified total water flow rate in the secondary cooling zone was carried out.A complex function was taken as the optimization objective to perform the casting.The complex function was composed of the functions of the entransy dissipation and surface temperature gradient of the slab.The optimal water distribution at the sections of the secondary cooling zone were obtained.The effects of the total water flow rate in the secondary cooling zone,casting speed,superheat and water distribution on the generalized constructal optimizations of the secondary cooling process were analyzed.The results show that on comparing the optimization results obtained based on the optimal water distributions of the 8 sections in the secondary cooling zone with those based on the initial ones,the complex function and the functions of the entransy dissipation and surface temperature gradient after optimization decreased by 43.25%,5.90%and 80.60%,respectively.The quality and energy storage of the slab had obviously improved in this case.The complex function,composed of the functions of the entransy dissipation and surface temperature gradient of the slab,was a compromise between the internal and surface temperature gradients of the slab.Essentially,it is also the compromise between energy storage and quality of the slab.The'generalized constructal optimization'based on the minimum complex function can provide an optimal alternative scheme from the point of view of improving energy storage and quality for the parameter design and dynamic operation of the solidification heat transfer process of slab continuous casting. | FENG HuiJun CHEN LinGen XIE ZhiHui DING ZeMin SUN FengRui | 2014 | Science China(Technological Sciences)2014，57，4： | 14 |
| 10 | De novo mutation in ATP6V1B2 impairs lysosome acidification and causes dominant deafness-onychodystrophy syndrome显示文摘 | Yongyi Yuan Jianguo Zhang Qing Chang Jin Zeng Feng Xin Jianjun Wang Qingyan Zhu Jing Wu Jingqiao Lu Weiwei Guo Xukun Yan Hui Jiang Binfei Zhou Qi Li Xue Gao Huijun Yuan Shiming Yang Dongyi Han Zixu Mao Ping Chen Xi Lin Pu Dai | 2014 | Cell Research2014，24，11： | 13 |
| 11 | Constructal optimization of cylindrical heat sources with forced convection based on entransy dissipation rate minimization显示文摘Based on constructal theory and entransy theory,the optimal designs of constant-and variable-cross-sectional cylindrical heat sources are carried out by taking dimensionless equivalent resistance minimization as optimization objective.The effects of the cylindrical height,the cylindrical shape and the ratio of thermal conductivity of the fin to that of the heat source are analyzed.The results show that when the volume of the heat source is fixed,there exists an optimal ratio of the center-to-centre distance of the fin and the heat source to the cylinder radius which leads to the minimum dimensionless equivalent thermal resistance.With the increase in the height of the cylindrical heat source and the ratio of thermal conductivity,the minimum dimensionless equivalent thermal resistance decreases gradually.For the heat source model with inverted variable-cross-sectional cylinder,there exist an optimal ratio of the center-to-centre distance of the fin and the heat source to the cylinder radius and an optimal radius ratio of the smaller and bigger circles of the cylindrical fin which lead to a double minimum dimensionless equivalent thermal resistance.Therefore,the heat transfer performance of the cylindrical heat source is improved by adopting the cylindrical model with variable-cross-section.The optimal constructs of the cylindrical heat source based on the minimizations of dimensionless maximum thermal resistance and dimensionless equivalent thermal resistance are different.When the thermal security is ensured,the optimal construct of the cylindrical heat source based on minimum equivalent thermal resistance can provide a new alternative scheme for the practical design of heat source.The results obtained herein enrich the work of constructal theory and entransy theory in the optimal design field of the heat sources,and they can provide some guidelines for the designs of practical heat source systems. | GONG ShuWen CHEN LinGen XIE ZhiHui FENG HuiJun SUN FengRui | 2016 | Science China(Technological Sciences)2016，59，4： | 12 |
| 12 | Equivalent thermal resistance minimization for a circular disc heat sink with reverting microchannels based on constructal theory and entransy theory显示文摘Thermal designs for microchannel heat sinks with laminar flow are conducted numerically by combining constructal theory and entransy theory. Three types of 3-D circular disc heat sink models, i.e. without collection microchannels, with center collection microchannels, and with edge collection microchannels, are established respectively. Compared with the entransy equivalent thermal resistances of circular disc heat sink without collection microchannels and circular disc heat sink with edge collection microchannels, that of circular disc heat sink with center collection microchannels is the minimum, so the overall heat transfer performance of circular disc heat sink with center collection microchannels has obvious advantages. Furthermore, the effects of microchannel branch number on maximum thermal resistance and entransy equivalent thermal resistance of circular disc heat sink with center collection microchannels are investigated under different mass flow rates and heat fluxes. With the mass flow rate increasing, both the maximum thermal resistances and the entransy equivalent thermal resistances of heat sinks with respective fixed microchannel branch number all gradually decrease. With the heat flux increasing, the maximum thermal resistances and the entransy equivalent thermal resistances of heat sinks with respective fixed microchannel branch number remain almost unchanged. With the same mass flow rate and heat flux, the larger the microchannel branch number, the smaller the maximum thermal resistance. While the optimal microchannel branch number corresponding to minimum entransy equivalent thermal resistance is 6. | WANG Liang XIE ZhiHui CHEN LinGen WANG Rong FENG HuiJun | 2021 | Science China(Technological Sciences)2021，64，1： | 11 |
| 13 | Performance optimization of a class of combined thermoelectric heating devices显示文摘A detailed model of thermally-driven combined thermoelectric(TE) heating device is established. The device consists of twostage TE heat pump(TTEH) and two-stage TE generator(TTEG) with four external heat exchangers(HEXs). Both internal losses and external heat transfer irreversibilities are considered in the model. The heating capacity and the coefficient of performance(COP) of the device are improved through numerical optimization,which is of great significance to the application of the device. The distribution of the total TE element number among four TE devices and the distribution of the total external heat conductance among the four external HEXs are optimized. The results show that both the reservoir temperatures of TTEG and TTEH have significant influences on the performance and the corresponding optimum parameters of the device. The COP can reach 0.14 after optimization when the temperature difference of heat source is 150 K and the temperature difference of heating is 10 K. | CHEN LinGen MENG FanKai GE YanLin FENG HuiJun XIA ShaoJun | 2020 | Science China(Technological Sciences)2020，63，12： | 10 |
| 14 | Fuzhengpaidu granule regulates immune activation molecules CD38 and human leukocyte antigen-D related on CD4+ and CD8+ T cells in patients with acquired immunodeficiency syndrome/human immunodeficiency virus显示文摘OBJECTIVE: To evaluate the effect of Fuzhengpaidu granule (FZPDG) on immune activation molecules CD38 and human leukocyte antigen-D related (HLA-DR) on CD4+ and CD8+ cells in HIV/AIDS patients, and to explore the underlying mechanism of this therapy. METHODS: Plasma changes in CD3+, CD4+, CD8+, CD3+CD4+CD38+, CD3+CD4+HLA-DR+, CD3+ CD8+CD38+, and CD3+CD8+HLA-DR+levels in HIV/ AIDS patients treated with FZPDG for six months were examined by flow cytometry and compared with levels in healthy controls. RESULTS: The clinical trial included 34 outpatients with HIV/AIDS. Before treatment, plasma levels of CD38+ and HLA-DR+ on CD4/CD8 cells were higherthan those in 28 health controls (P<0.05). There were no significant changes in serum levels of CD3+, CD4+, and CD8+ T cells between pretreatment baseline versus after treatment, which were 82.85% ± 5.41% , 14.57% ± 10.31% and 54.55% ± 11.43% before treatment and 79.15% ± 8.21% , 19.96% ± 9.58% and 56.36% ± 11.67% after treatment, respectively (P>0.05). Plasma levels of CD3+ CD4+CD38+and CD3+CD4+HLA-DR+were 2.3%± 2.2% and 7.8%±5.5% before treatment and 1.2%± 0.8% and 2.6%±1.0% after treatment, respectively. Plasma levels of CD3+CD8+CD38+ and CD3+CD8+ HLA-DR+ were 41.4%±13.4% and 17.8%±11.3% beforetreatment,whichchangedto27.1%±10.2%and 3.8%±2.4%aftertreatment,respectively(P<0.05). CONCLUSION: HIV/AIDS patients exhibited an immune activation profile following FZPDG treatment. A potential mechanism of action for FZPDG appears to lie in its ability to up-regulate CD38 and HLA-DR levels on CD4+ T cells, and down-regulate them on CD8+ cells, thereby modulating immune activation of CD4+and CD8+T cells. | Feng Jiang Rongxin Zhang Zhenfang Gu Huailing Zhang Huijun Guo Xin Deng Jian Liang | 2013 | Journal of Traditional Chinese Medicine2013，33，4： | 8 |
| 15 | Constructal entransy dissipation rate minimization of a rectangular body with nonuniform heat generation显示文摘Based on construtal theory, a nonuniform heat generation problem in a rectangular body is investigated in this paper. Entransy dissipation rate(EDR) is taken as the optimization objective. The optimal body shapes with constant and variable widths of the high conductivity channel(HCC) are derived. For the rectangular first order assembly(RFOA) with constant cross-section HCC, the shape of the RFOA and width ratio of the HCCs are optimized, and the double minimum EDR is obtained. The heat transfer performance of the RFOA becomes worse when the nonuniform coefficient increases. For the RFOA with variable cross-section HCC, the EDR of the RFOA can be minimized for four times. Compared the optimal construct based on minimum EDR of the RFOA with that based on minimum maximum temperature difference, the shape of the former optimal construct is tubbier, and the average temperature difference is lower. In the practical design of electronic devices, when the thermal safety is ensured, the constructal design scheme of the former optimal construct can be adopted to improve the global heat transfer performance of an electronic device. | FENG HuiJun CHEN LinGen XIE ZhiHui SUN FengRui | 2016 | Science China(Technological Sciences)2016，59，9： | 7 |
| 16 | Generalized constructal optimization of strip laminar cooling process based on entransy theory显示文摘A strip laminar cooling process is investigated in this paper. Entransy theory and generalized constructal optimization are introduced into the optimization. Total water flow amount(WFA) in the laminar cooling zone(LCZ) and complex function are taken as the constraint and optimization objective, respectively. The entransy dissipation(ED) and maximum temperature different(MTD) of the strip are simultaneously considered in the complex function. WFA distributions of the headers in the LCZ are optimized. The effects of the total WFA, strip thickness and cooling water temperature on the optimal results are analyzed.The optimal cooling scheme is the eleventh cooling mode for the considered total 257 cooling schemes, and the complex function,ED and MTD of the strip are decreased by 11.59%, 5.59% and 17.58% compared with the initial cooling scheme, respectively.The total WFA and strip thickness have the obvious influences on the optimal cooing scheme, but the cooling water temperature has no influence in the parameter analysis range of this paper. The 'generalized optimal construct' derived by minimum complex function shows a compromise between the energy retention and quality of the strip. | FENG HuiJun CHEN LinGen LIU Xiong XIE ZhiHui SUN FengRui | 2016 | Science China(Technological Sciences)2016，59，11： | 7 |
| 17 | Constructal entransy dissipation rate minimization for X-shaped vascular networks显示文摘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. | FENG HuiJun CHEN LinGen XIE ZhiHui | 2019 | Science China(Technological Sciences)2019，62，12： | 7 |
| 18 | A multi-objective study on the constructal design of non-uniform heat generating disc cooled by radial-and dendritic-pattern cooling channels显示文摘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 pattern.To reveal thermal and flow characteristics,a composite objective function comprised of the maximum temperature difference(MTD)and pumping power is constructed.The deployment pattern of cooling channels contains two cases,i.e.,the radial-pattern and dendritic-pattern.By capitalizing on constructal design method together with finite element method,the diameter of radial-pattern cooling channels is optimized in the first place.Next,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 conditions.Furthermore,NSGA-II algorithm is introduced into the multiobjective problem.Upon obtaining its Pareto optimal solution set,Topsis method is invoked to yield the optimal solutions under given weighted coefficients.The heat generation over the entire body and the volume ratio of cooling channels operate as the primary constraints.Based on these premises,constructal design will be stepwise performed by varying three degrees-offreedom.The obtained results state that more heating components or devices should be installed as close to the cooling water inlet as possible.This can further reduce MTD at the same cost of pumping power,thereby improve thermal and flow performance and prolong the lifespan of devices.As 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-objective will inevitably elicit the vitiation of the alternative. | CHEN Chen YOU Jiang FENG HuiJun CHEN LinGen | 2021 | Science China(Technological Sciences)2021，64，4： | 7 |
| 19 | Associations between haemodynamics and wall enhancement of intracranial aneurysm显示文摘Background and purpose Previous studies have reported about inflammation processes(IPs)that play important roles in aneurysm formation and rupture,which could be driven by blood flow.IPs can be identified using aneurysmal wall enhancement(AWE)on high-resolution black-blood MRI(BB-MRI)and blood flow haemodynamics can be demonstrated by four-dimensional-flow MRI(4D-flow MRI).Thus,this study investigated the associations between AWE and haemodynamics in unruptured intracranial aneurysms(IA)by combining 4D-flow MRI and high-resolution BB-MRI.Materials and methods Between April 2014 and October 2017,48 patients with 49 unruptured IA who underwent both 4D-flow MRI and high-resolution BB-MRI were retrospectively included in this study.The haemodynamic parameters demonstrated using 4D-flow MRI were compared between different AWE patterns using the Kruskal-Wallis test and ordinal regression.Results The results of Kruskal-Wallis test showed that the average wall shear stress in the IA(WSSavg-IA),maximum through-plane velocity in the adjacent parent artery,inflow jet patterns and the average vorticity in IA(vorticityavg-IA)were significantly associated with the AWE patterns.Ordinal regression analysis identified WSSavg-IA(p=0.002)and vorticityavg-IA(p=0.033)as independent predictors of AWE patterns.Conclusion A low WSS and low average vorticity were independently associated with a high AWE grade for IAs larger than 4 mm.Therefore,WSS and average vorticity could predict AWE and circumferential AWE. | Miaoqi Zhang Fei Peng Xin Tong Xin Feng Yunduo Li Huijun Chen Hao Niu Baorui Zhang Guangrong Song Youxiang Li Peng Liu Aihua Liu Rui Li | 2021 | Stroke & Vascular Neurology2021，6，3： | 7 |
| 20 | Optimal Performance Characteristics of Subcritical Simple Irreversible Organic Rankine Cycle显示文摘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. | CHEN Weijian FENG Huijun CHEN Lingen XIA Shaojun | 2018 | Journal of Thermal Science2018，27，6： | 6 |
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