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Isotopic dependence of the yield ratios of light fragments from different projectiles and their unified neutron skin thicknesses

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Nuclear Science and Techniques 2024年第3期35卷 228-236页

作者： Ting-Zhi Yan Shan Li school of energy and power engineering Northeast Electric Power UniversityJilin 132012China

The yield ratios of neutron-proton(R(n/p))and^(3)H-^(3)He(R(^(3)H∕^(3)He))with reduced rapidity from 0 to 0.5 were simulated at 50 MeV/u even-even ^(36−56)Ca+^(40)Ca,even-even ^(48−78)Ni+^(58)Ni,and ^(100−139)Sn(every third isotopes)+112 Sn for full reduced impact parameters using the isospin-dependent quantum molecular dynamics(IQMD)*** neutron and proton density distributions and root-mean-square radii of the reaction systems were obtained using the Skyrme-Hartree-Fock model,which was used for the phase space initialization of the projectile and target in *** defined the unified neutron skin thickness asΔRnp=^(1∕2) n−^(1∕2)p,which was negative for neutron-deficient *** unifiedΔRnp values for nuclei with the same relative neutron excess from different isotopic chains were nearly equal,except for extreme neutron-rich isotopes,which is a type of scaling *** yield ratios of the three isotopic chain-induced reactions,which depended on the reduced impact parameter and unified neutron skin thickness,were *** results showed that both R(n/p)and R(^(3)H∕^(3)He)decreased with a reduced impact parameter for extreme neutron-deficient isotopes;however,they increased with reduced impact parameters for extreme neutron-rich isotopes,and increased with theΔRnp of the projectiles for all reduced impact *** addition,a scaling phenomenon was observed betweenΔR np and the yield ratios in peripheral colli-sions from different isotopic chain projectiles(except for extreme neutron-rich isotopes).Thus,R(n/p)and R(^(3)H∕^(3)He)from peripheral collisions were suggested as experimental probes for extracting the neutron or proton skin thicknesses of non-extreme neutron-rich nuclei from different isotopic chains.

关键词： Exotic nuclei Unified neutron skin thickness Yield ratios IQMD

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Numerical Investigation on Characteristics of Supercritical CO_(2)Heat Transfer in Vertical Circular Tubes with Circumferentially Half-Side Heating

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Journal of Thermal Science 2024年第5期33卷 1744-1756页

作者： ZHANG Yan ZHANG Xinyi YAN Chenshuai WU Wenhua GAO Erman school of energy and power engineering Northeast Electric Power UniversityJilin 132012China

The design of heat exchangers in the advanced supercritical power conversion system cannot be separated from the study of heat transfer ***-side heating mode is often encountered for solar receiver and supercritical ***,the characteristics of supercritical CO_(2)(sCO_(2))convection heat transfer in vertical tubes with circumferentially half-side heating was numerically investigated through the SST k-ωturbulent model which matches well with the experimental ***,heat transfer between sCO_(2)upflow and downflow was *** to film boiling heat transfer at subcritical pressure,numerical results were processed according to the supercritical pseudo-phase transition hypothesis,with liquid-like phase in the tube core region and vapor-like film in the region near the heated tube *** structure of two layers was demarcated by pseudo-critical temperature T_(pc).Therefore,sCO_(2)heat transfer was assessed according to double thermal resistances caused by vapor-like film near the wall and core liquid-like *** findings suggest that wall temperature for upflow is higher than that for downflow,which is attributed to larger thermal resistance in the fluid domain for upflow than that for *** difference guarantees the excellent heat transfer performance for downflow than *** is also further concluded that the formation of vapor-like film near the wall due to pseudo-phase transition plays a key role in dominating wall temperature and inducing heat transfer deterioration in half-side heating *** present contribution is significant to the design of supercritical heat exchanger under half-side heating mode.

关键词： supercritical CO_(2) pseudo-phase transition half-side heating thermal resistance flow direction

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Thermal-hydraulic performance analysis and multi-objective optimization of a microchannel with staggered semi-elliptical ribs

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Science China Technological Sciences 2024年第10期67卷 3152-3167页

作者： CUI Pan LIU Wei LIU ZhiChun school of energy and power engineering Huazhong University of Science and Technology

To enhance the cooling capacity of traditional microchannels for high heat flux electronic devices,a microchannel design with staggered semi-elliptical ribs is proposed in this *** numerical simulations,the flow characteristics of the designed microchannel are compared with those of a smooth one,and the effects of rib width（Wr）,rib height（Hr）,and rib length（Lr）,on the thermal-hydraulic performance are investigated under laminar flow *** results show that the periodically arranged ribs induce periodic vortices within the microchannel,effectively promoting fluid mixing and enhancing heat *** Hrhave similar effects on microchannel performance,with an increase in them leading to an enhanced thermal performance at the expense of deteriorated hydraulic ***,Lrhas a comparatively weaker influence,with both the heat transfer and flow resistance initially growing with increasing Lrand then *** strike a balance between the two performances,a multi-objective optimization on the three geometrical parameters is conducted at a Reynolds number（Re） *** with simulation data,artificial neural networks are trained as surrogate models,and a multi-objective genetic algorithm is employed to derive the Pareto *** the TOPSIS decision-making method,an optimal compromise solution is determined as Wr=0.2415 mm,Hr=0.0976 mm,and Lr=0.6486 *** testing on the optimized microchannel reveals that it exhibits high heat transfer,middle flow resistance,and excellent overall performance,with the performance evaluation criterion（PEC） falling between 1.572 and 1.723 within the Re range of 220–660.

关键词： heat transfer enhancement microchannel semi-elliptical rib numerical simulation multi-objective optimization

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Study on the influence of pneumatic probe on the wake flow field of transonic turbine cascade

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Acta Mechanica Sinica 2024年第7期40卷 43-54页

作者： Qingdian Zhang Hongwei Ma Anqi Xiao Yingcun Liu Junde Guo school of energy and power engineering Beihang UniversityBeijing 102206China

The pneumatic probe is widely used for contact measurements in turbomachinery flow field ***,it inevitably interferes with the original flow field,leading to additional errors,particularly in wake flow fields or transonic regions with significant pressure *** study employed Reynolds-Averaged Navier-Stokes delete and high-fidelity numerical simulation to investigate the impact of an inserted pneumatic probe on the wake flow field of a transonic turbine blade and compared it to the baseline flow *** indicate that the probe causes the shock waves premature occurrence in the high subsonic wake region near the turbine blade trailing *** shock waves affect vortex shedding by thickening the boundary layer near the trailing edge and changing the shedding pattern from high-frequency-low-energy to *** addition,the extra flow loss is incurred,and the blade's heat transfer characteristic is *** research provides a reference for testing experiments in complex transonic flow fields,guiding experimental researchers to minimize instrument interference with the original flow field.

关键词： Pneumatic probe Wake flow field Transonic turbine cascade Shock wave High-fidelity numerical simulation

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An uncertainty investigation for liner impedance eduction methods

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Chinese Journal of Aeronautics 2024年第3期37卷 49-59页

作者： Weihao SHI Xiaodong JING school of energy and power engineering Beihang UniversityBeijing 100191China

Impedance eduction methods have been developed for decades to meet the increasing need for high-quality impedance data in the design and optimization of acoustic *** this end,it is important to fully investigate the uncertainty problem,to which only limited attention has been devoted so *** paper considers the possibility of acoustically-induced structural vibration as a nonnegligible uncertainty or error source in impedance eduction *** the frequency moves away from the resonant frequency,with the increase in the value of cavity reactance,the acoustic particle velocity inside liner orifices possibly decreases to the extent comparable to the vibration velocity of liner facing ***,the acoustically-induced vibration,although generally being weak except at the inherent structural frequencies,may considerably affect the impedance eduction results near the anti-resonant frequency where the liner has poor *** demonstrate the effect of structural vibration,the vibration velocity of liner facing sheet is estimated from the experimentally educed admittance of the liner samples whose orifices are sealed with ***,a three-dimensional numerical model is set up,in which normal particle velocity is introduced over the solid portion of liner facing sheet to imitate structural vibration,rather than directly solving the acoustic-structural coupling *** shown by the results,the vibration of liner facing sheet,whose velocity is as small as estimated by the experiment,can result in anomalous deviation of the educed impedance from the impedance model near the anti-resonant *** trend that the anomalous deviation varies with frequency is numerically captured.

关键词： Impedance eduction Uncertainty analysis Acoustically-induced structural vibration Anti-resonant frequency Perforated liner

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Microstructure Characteristics and Possible Phase Evolution of the Coal Gangue-Steel Slag Ceramics Prepared by the Solid-State Reaction Methods

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Journal of Wuhan University of Technology(Materials Science) 2024年第4期39卷 921-930页

作者：刘文洁 WANG Yang LI Jingtao 李宝让 school of energy Power and Mechanical EngineeringNorth China Electric Power UniversityBeijing 102206China

Industrial wastes such as steel slag and coal gangue *** chosen as raw materials for preparing ceramic via the conventional solid-state reaction *** steel slag and coal gangue mixed in various mass ratios,from 100%steel slag to 100%coal gangue at 10%intervals,microstructure and possible phase evolution of the coal gangue-steel slag ceramics were investigated using X-ray powder diffraction,scanning electron microscopy,mercury intrusion porosimetry and Archimedes boiling *** experimental results suggest that the phase compositions of the as-prepared ceramics could be altered with the increased amount of coal gangue in the *** anorthite-diopside eutectic can be formed in the ceramics with the mass ratios of steel slag to coal gangue arranged from 8:2 to 2:8,which was responsible for the melting of the steel slag-coal gangue ceramics at relatively high *** investigations on the microstructure suggested that the addition of the proper amount of steel slag in ceramic compositions was conducive to the pore formation and further contributed to an increment in porosity.

关键词： steel slag-coal gangue ceramics synthesis phase evolution microstructure characteristics

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Thermodynamic and Economic Analysis of a Conceptual System Combining Sludge Gasification,SOFC,Supercritical CO_(2)Cycle,and Organic Rankine Cycle

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Journal of Thermal Science 2024年第4期33卷 1491-1508页

作者： LV Jiayang WANG Chizhong CHEN Heng PAN Peiyuan XU Gang ZHANG Guoqiang school of energy Power and Mechanical EngineeringNorth China Electric Power UniversityBeijing102206China

In order to reduce the environmental impact of conventional sludge treatment methods and to utilize the energy in sludge more effectively,a coupled system based on sewage sludge gasifier(SSG),solid oxide fuel cells(SOFC),supercritical CO_(2)cycle(S-CO_(2)),and organic Rankine cycle(ORC)is *** clean syngas obtained from sludge gasification is mixed with CH4 and then first utilized by the fuel *** exhaust gas from the fuel cell is fully combusted in the afterburning chamber and then enters the bottom cycle system consisting of S-CO_(2)&ORC to generate *** understand the performance of the system,thermodynamic and economic analyses were conducted to examine the project's *** thermodynamics as well as the economics of the coupled system were analyzed to arrive at the following conclusions,the power production of the system is 37.34 MW;the exergy efficiency is 55.62%,and the net electrical efficiency is 61.48%.The main exergy destruction is the gasifier and SOFC,accounting for 62.45%of the total exergy *** takes only6.13 years to repay the construction investment in the novel system,and the project obtains a NPV of 17723820USD during 20 years *** above findings indicate that the new coupled system has a better performance in terms of energy utilization and economy.

关键词： sewage sludge gasifier SOFC supercritical CO_(2)cycle organic Rankine cycle multi-system coupling

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Multi-Objective Multi-Variable Large-Size Fan Aerodynamic Optimization by Using Multi-Model Ensemble Optimization Algorithm

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Journal of Thermal Science 2024年第3期33卷 914-930页

作者： XIONG Jin GUO Penghua LI Jingyin school of energy and power engineering Xi’an Jiaotong UniversityXi’an710049China

The constrained multi-objective multi-variable optimization of fans usually needs a great deal of computational fluid dynamics(CFD)calculations and is *** this study,a new multi-model ensemble optimization algorithm is proposed to tackle such an expensive optimization *** multi-variable and multi-objective optimization are conducted with a new flexible multi-objective infill *** addition,the search direction is determined by the multi-model ensemble assisted evolutionary algorithm and the feature extraction by the principal component analysis is used to reduce the dimension of optimization ***,the proposed algorithm and other two optimization algorithms which prevail in fan optimizations were compared by using test *** the same number of objective function evaluations,the proposed algorithm shows a fast convergency rate on finding the optimal objective function ***,this algorithm was used to optimize the rotor and stator blades of a large axial fan,with the efficiencies as the objectives at three flow rates,the high,the design and the low flow ***-two variables were included in the optimization *** results show that compared with the prototype fan,the total pressure efficiencies of the optimized fan at the high,the design and the low flow rate were increased by 3.35%,3.07%and 2.89%,respectively,after CFD simulations for 500 fan candidates with the constraint for the design *** optimization results validate the effectiveness and feasibility of the proposed algorithm.

关键词： multi-objective optimization surrogate-assisted evolutionary algorithm axial fan computational fluid dynamics aerodynamic optimization

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Numerical Analysis of Heat Transfer Characteristics to Supercritical CO_(2) in a Vertical Mini-Channel:Transition and Pseudo-Boiling

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Journal of Thermal Science 2024年第1期33卷 101-113页

作者： YUAN Baoqiang WANG Wei XIN Gongming DU Wenjing school of energy and power engineering Shandong UniversityJi'nan 250061China

Large eddy simulations have been conducted to study upward transitional flows and heat transfer characteristics of supercritical CO_(2) in a vertical *** numerical simulation was carried out on a modified buoyantPimpleFOAM solver in OpenFOAM 7,and was verified using experiment *** results indicate that increasing the Grashof numbers can reduce the flow stability and make the flow transition *** are four stages of heat transfer in the transition process,i.e.,weakened,improved,recovered and normal heat *** heat transfer phenomena in the transition process were explained from three perspectives:thermal boundary layer theory,turbulent transport and pseudo-boiling *** transfer enhancement during transition is related to the transport of supercritical molecular clusters,and these molecular clusters are regarded as pseudo-bubbles in pseudo-boiling *** flow pattern of the pseudo-phases in the dia-Widom process contains single-phase flow,steady pseudo-film flow,unsteady pseudo-film flow,partial pseudo-bubbles flow and flocculent pseudo-film ***-bubbles have similar behaviors to subcritical bubbles,i.e.,break-up,deformation,condensation and *** researches in this work are favorable for understanding the heat transfer mechanism of supercritical fluids during flow transition.

关键词： supercritical heat transfer large eddy simulation transition pseudo-boiling

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Investigations of Water Flow Behaviors Induced by Local Temperature Variations through a Single Rough Fracture for the Enhanced Geothermal Systems

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Journal of Thermal Science 2024年第3期33卷 1055-1064页

作者： LI Jiawei YE Lin Department of energy and power engineering Tsinghua UniversityBeijing100084China school of power and energy Northwestern Polytechnical UniversityXi’an710072China

In recent years,Enhanced Geothermal System(EGS)technologies have been applied to the geothermal resources production in the Hot Dry Rock(HDR).The core of EGS technologies is to adopt hydraulic fracturing in the reservoir to create a connected network of discrete fractures with the consideration of water as a working fluid for hydraulic fracturing and heat *** paper investigates the characteristics of water flow behaviors through a single rough fracture under different temperature and pressure conditions.A single fracture model with rough fracture surfaces is constructed and then characterized,and influences of the anisotropic factor on the average tortuosity and frictional resistance coefficient of water flow through a single fracture with rough surfaces have been compared and *** consideration of other impacting factors(temperature,pressure,fracture roughness),the impact of mass flow rate has also been *** simulation results present that changes of average tortuosity for water flow through a single rough facture are mainly affected by *** can be observed that higher temperature leads to larger average tortuosity but the frictional resistance coefficient shows an opposite *** for pressure conditions,it is found that effects of pressure on average tortuosity and frictional resistance coefficient is very small,which can be neglected under high pressure ***,the average tortuosity shows a progressively linear relationship with the mass flow *** the contrary,the frictional resistance coefficient has a negative relationship with the mass flow *** is revealed that when the mass flow rate reaches a critical point,the influences of temperature on the frictional resistance coefficient will be *** of single rough fractures with different anisotropic factors show that values of average tortuosity and frictional resistance coefficient have positive relationships with the increase

关键词： single rough fracture tortuosity frictional resistance enhanced geothermal system

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