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2026年第60卷第7期
Special Topic Frontier Applications of Supercritical Fluids
摘要：The unique dissolution and reaction characteristics of supercritical water（SCW）facilitate the efficient conversion of biomass into hydrogen.However，drastic fluctuations in physical properties within the near-critical region lead to complex thermodynamic properties and process instabilities，which significantly hinder system efficiency and stability.To elucidate these anomalous thermodynamic behaviors，an analytical method based on the higher-order derivatives of the Gibbs free energy was proposed.Isobaric heat capacity，isobaric expansion coefficient，and isothermal compressibility，along with their dimensionless forms，were analyzed using fluid data extracted from REFPROP via Matlab.The variations of these three parameters of water with respect to reduced temperature（Tr）and reduced pressure（pr）during isobaric and isothermal processes were systematically investigated.The trajectories of the extrema for each parameter were identified，based on which a comprehensive regional phase diagram of water in the supercritical state was plotted.The results demonstrate that the proposed method accurately captures the abrupt changes in physical properties within the anomalous region.Specifically，at Tr≈1.02 and pr≈1.1，the isobaric heat capacity reaches approx.3.4 times its value in the conventional region，while the isothermal compressibility increases nearly twofold.Accordingly，the supercritical region of water is classified into liquid-like，gas-like，and solid-like regimes，providing explicit boundaries for the optimization of operating conditions. Integrating the thermodynamic analysis of SCW with practical conditions ensures that operating temperatures and pressures avoid high-risk anomalous regions，thereby effectively reducing equipment failure and process instability.关键词：supercritical water;Gibbs free energy;anomalous region;biomass-to-hydrogen conversion138|24|0更新时间：2026-07-09- 摘要：To accurately characterize the complex flow process of supercritical carbon dioxide（sCO2）leakage flow in a scallop bionic seal cavity and to elucidate the mechanism of turbulent kinetic energy（TKE）dissipation，a high-order numerical simulation method for real gas flows with strongly variable physical properties in rotating machinery was proposed.In this method，the uni-particle upwind scheme was employed for numerical flux splitting，while third-order numerical flux reconstruction was achieved via the simple high-resolution upwind method.Euler's fully implicit time-stepping iterative method was implemented，supporting open multi-processing（OpenMP）shared-memory parallel computing.A coupled iterative calculation method，integrating a real gas equation of state（EOS）with Helmholtz free energy-based thermophysical property lookup table，was adopted to accurately capture the nonlinear variations in CO2 thermophysical properties，with calculation deviations below 0.5%.The accuracy of this numerical simulation method was validated through molecular tracing experiments.Furthermore，the spatial distribution of leakage flow vortices within the scallop bionic seal cavity and its impact on the TKE dissipation rate were analyzed in detail.The results indicate that as the sCO2 leakage flow enters the seal cavity，expansion occurs，while the local Mach number remains below 0.1.Under the rapid shear of the rotor，the leakage flow generates vortices that exhibit migration，splitting，and separation behaviors.The normalized helicity of the leakage flow exhibits alternating positive and negative values，indicating the presence of multiple sets of counter-rotating（clockwise and counterclockwise）vortices within the seal cavity.Each set of counter-rotating vortices increases the dimensionless TKE dissipation rate to over 1.95 × 108，thereby effectively improving sealing performance.Moreover，the extrema of the TKE dissipation rate were identified at the outer boundaries of these counter-rotating vortices，where changes in vortex rotation direction also increase the TKE dissipation rate of the leakage flow.关键词：supercritical carbon dioxide;scallop bionic seal;leakage flow;turbulence kinetic energy dissipation;vortex distribution48|8|0更新时间：2026-07-09
- 摘要：To address the limited understanding of windage loss mechanisms in complex back gaps featuring weight reduction structures，numerical simulations are conducted to investigate the effects of key parameters such as rotational Reynolds number，throughflow Reynolds number and relative gaps on windage losses and to elucidate the flow mechanisms within the gaps.A laminar theoretical model for slope wall gaps is developed based on differential shear stress theory，and a simplified windage loss model for impeller back gaps is proposed by representing the complex back gap as an equivalent coupling of two relative gaps.Results demonstrate that windage losses in impeller back gaps increase with rising rotational and throughflow Reynolds numbers but decrease with increasing relative gaps.In this superimposed flow regime，a compensatory radial inflow is formed in the core region，causing radial velocities to exhibit two directions.At a rotational Reynolds number of 1×106，the windage loss in the impeller back gap featuring weight reduction structure is reduced by 7.27% compared to that in a standard disk-type impeller back gap.The flow within the gap is classified into 4 characteristic regions；the rotor pumping region is induced by the superposition of circumferential and radial flows，and an increase in throughflow Reynolds number suppresses the pumping effect，thereby altering the velocity distribution of fluid in the core region and exacerbating windage losses.The proposed windage loss model for complex impeller back gaps predicts windage losses with a relative deviation of less than 15% compared with numerical results. These findings provide both theoretical validation and engineering guidance for aerodynamic optimization design of supercritical carbon dioxide（sCO2）radial inflow turbines.关键词：supercritical carbon dioxide;radial inflow turbine;impeller back gap;windage loss;pumping effect44|11|0更新时间：2026-07-09
Special Topic Cooling Characteristics
摘要：To further enhance the cooling efficiency of double-wall turbine blades，a novel expansion angle crater film hole was conceived.Three expansion angles（α=25°，35°，45°）were designed，and the influences ofαon the overall cooling effectiveness and flow field structure of the double-wall structure were analyzed under four blowing ratios（M=0.5，1.0，1.5，2.0）.The results indicate that，compared to conventional cylindrical film holes，the expansion angle crater film holes facilitate the extension of the film in both the streamwise and spanwise directions，thereby expanding the coverage area of the cooled air on the wall.At M= 0.5，1.0，the optimal improvement in the overall cooling effectiveness of the double-wall cooling structure was achieved withα=45°.However，at M=1.5，2.0，the crater film holes withα=25°，35°exhibited the best overall cooling performance.It was found that the novel expansion angle crater film hole generates a counter-rotating kidney vortex pair（CRKVP），which suppresses the development of the kidney vortex and enhances the adhesion of the cooled air to the wall surface.Furthermore，the decay rate of the CRKVP in the streamwise direction increased with largerαvalues.Although the expansion angle crater film holes increased the aerodynamic loss of the double-wall cooling structure compared to conventional cylindrical film holes，the aerodynamic losses generated by the crater film holes withα=25°，35°were relatively low at M=0.5—1.5，exceeding those of conventional cylindrical film holes by only 5.07%—15.05%.These findings provide numerical support for the design and selection of film holes（with high cooling efficiency and low loss）for air-cooled turbine blades.关键词：film cooling;turbine blade;crater film hole;kidney vortex31|8|0更新时间：2026-07-09- 摘要：To elucidate how the structural parameters of the three-tower-in-one indirect air-cooling system influence its operational characteristics in summer，a coupled calculation model for the system was established under the turbine rated load condition in summer，using commercial simulation software and Internet communication protocols.The accuracy of the system's simulation model was verified，and the impacts of key structural parameters—including tower height，air inlet diameter，flue gas exhaust height，and chimney diameter—on the system's operational performance were quantitatively analyzed.The results demonstrate that，as the tower height and air inlet diameter increase，the unit back pressure significantly drops.Specifically，as the tower height increases from 190 m to 206 m，the unit back pressure is reduced by 0.73 kPa；as the air inlet diameter increases from 126 m to 138 m，the unit back pressure decreases by 2.04 kPa.The influence of flue gas exhaust height on the unit back pressure was found to be minimal，so much so that it is negligible in engineering practice.When the chimney diameter is increased from 6.5 m to 10.5 m，the unit back pressure increases by 0.37 kPa.The increase in back pressure gradually levels off as chimney diameter grows，indicating a diminishing impact of chimney area on unit back pressure. Considering both investment costs and operational benefits，it is recommended that the tower height and air inlet diameter should be moderately increased，while the chimney diameter should be slightly decreased.These findings provide a theoretical basis for the structural optimization and improved unit economics of three-tower-in-one indirect air-cooling systems.关键词：three-tower-in-one indirect air-cooling system;operational characteristics;systemlevel simulation;structural parameters28|16|0更新时间：2026-07-09
- 摘要：In response to the limited numerical simulations on the humidity field and the restricted studies on heat-moisture barrier performance of air curtains in cold storage，a horizontal doublelayer air curtain in a cold storage facility was studied in this paper.An experimental measurement system for heat and moisture transfer parameters of the air curtain was developed，and a numerical model for heat and moisture transfer capable of characterizing flow and load characteristics was established.The model was validated against experimental data，yielding average relative errors of 2.86%（temperature），1.86%（relative humidity），and 11.4%（air velocity）at the measuring points.Based on this model，key structural parameters of the air curtain，including the air outlet angle，outlet size，and outlet position，were optimized，leading to a significant improvement in heat-moisture barrier efficiency.The effects of different operating modes，personnel passage，and goods stacking on the internal temperature-humidity distribution and barrier performance of the air curtain were analyzed.The results suggest that after structural optimization，the average temperature and relative humidity inside the cold storage are reduced by 0.4℃ and 0.6%，respectively，while the heat-moisture barrier efficiency is increased by 9.7%.The heat-moisture barrier efficiency of a single-layer cold air curtain is 15.4% higher than that of a single-layer hot air curtain.The barrier performance of the double-layer configuration is superior to that of the single-layer one，with the counter-flow mode achieving a 7.9% higher efficiency than the co-flow mode.Although the impact of personnel passage is position-dependent，the total heat load remains 41.3% lower than the baseline case without an air curtain even under the most significant impact.Furthermore，a gradual attenuation in the barrier performance of the air curtain is observed as the stacking density of goods rises，with the total barrier efficiency under high-stacking conditions dropping by 21% compared to that under low-stacking conditions.These findings serve as a reference for the numerical analysis，structural design，and operational control of air curtains in cold storage.关键词：cold storage;air curtain;barrier performance;heat and moisture transfer25|8|0更新时间：2026-07-09
Special Topic Combustion Control
摘要：To clarify the motion mechanism of ionic liquid-modified fuels in electrostatic fields and to efficiently regulate the fluid motion behavior of the micro-scale flow field under electrostatic fields，the electrohydrodynamic（EHD）effects generated in dielectric fuel liquids near a needleplate electrode structure were characterized using particle image velocimetry（PIV）.The effects of varying electric field conditions and ionic liquid modification on fluid motion characteristics were systematically investigated.The results show that under high-voltage electrostatic fields，the flow characteristics of the dielectric fluid are significantly influenced by the applied voltage magnitude and electrode gap.Furthermore，the flow disturbance velocity rises as the voltage and electrode gap increase.Through the modification of fuel liquids with ionic liquids，it was observed that the viscosity of the blended solution increases nonlinearly with the volume fraction of the ionic liquid，while the electrical conductivity varies non-monotonically with ionic liquid fraction，first increasing and then decreasing.Contrary to the conventional enhancement of EHD effects via highly conductive additives，the addition of ionic liquids was found to generate a reverse shielding electric field near the electrodes due to the directed migration of anions and cations.This results in a local electric field shielding effect that suppresses the EHD motion characteristics of the solution.Specifically，with the addition of 1.0% volume of ionic liquid，the flow velocity of the solution under the electric field was reduced by 91.9%.This research elucidates the regulatory mechanism of ionic liquid modification on the EHD behavior of fuels，providing a theoretical basis and experimental support for the development of novel electronicallycontrolled fuel injection and microfluidic drive technologies.关键词：electrohydrodynamics;needle-plate electrode structure;dielectric fluids;ionic liquid modification;electric field shielding;particle image velocimetry20|6|0更新时间：2026-07-09- 摘要：To investigate the hydrogen diffusion characteristics and influencing factors in the event of hydrogen leakage from hydrogen fuel cell vehicles running in tunnels，a hydrogen leakage and diffusion model for fuel cell trucks traveling through tunnels was established using computational fluid dynamics.The diffusion process and distribution characteristics of the leaked hydrogen in the tunnel were studied，and the effects of varying vehicle speeds and leakage mass flow rates on the hydrogen diffusion process were compared and analyzed.The results indicate that while the hydrogen concentration was higher at the leaking orifice of the hydrogen storage tank during the initial leakage phase，it became higher at the non-leaking orifice after 2 s，where a wider diffusion range and longer diffusion distance were observed.At lower vehicle speeds，hydrogen diffused over greater distances and covered a broader area，facilitating the accumulation of large-volume combustible clouds.Specifically，for a simultaneous leak from four hydrogen storage tanks at a vehicle speed of 20 km/h，the volume of the combustible cloud reached 453.28 m3 after 20 s.As the vehicle speed increased，the enhanced airflow in the tunnel promoted hydrogen dilution and suppressed its accumulation；at a vehicle speed of 100 km/h，the volume of the formed combustible cloud was reduced by 96.8% compared to that at 20 km/h.Furthermore，it was found that higher hydrogen leakage mass flow rates resulted in more extensive distribution ranges，longer diffusion distances，and larger volumes of combustible clouds.Compared to a single leaking orifice with a diameter of 2.5 mm，the volume of the combustible cloud was 5.76 times larger when four orifices of the same size leaked simultaneously.关键词：fuel cell trucks;hydrogen leakage and diffusion;vehicle speed;leakage mass flow rate;combustible clouds25|12|0更新时间：2026-07-09
- 摘要：To clarify how steam addition affects the swirl combustion of cracked ammonia and to identify the optimal steam blending ratios（H）for various cracking rates（C），the combustion and pollutant emission characteristics of cracked ammonia in a premixed swirl combustor were investigated. Experimental methods including combustion and flashback limit measurements，digital imaging，OH plane laser-induced fluorescence（OH-PLIF），particle image velocimetry（PIV），and exhaust gas analysis were employed.Furthermore，the mechanism of nitrogen oxide（NOx）reduction through steam addition was elucidated using a chemical reaction network（CRN）.The results indicate that steam addition significantly weakens the combustion intensity.Compared to H=0，the combustion equivalence ratio is reduced by 21.1%—50.9% for 0.2＜C＜0.4 when H is set to 0.1 and 0.2.Correspondingly，the flame chemiluminescence is weakened，the OH signal intensity decreases by 66%—75%，and NH3 emissions in the exhaust gas increase by 18%—368%.Conversely，steam addition significantly enhances combustion uniformity and suppresses NOx emissions. Specifically，flame symmetry is improved by 11.8% and 56.3% at H=0.1 and 0.2，respectively，with a 60%—90% reduction in NOx emissions.This NOx reduction is attributed to the combined effects of decreased formation rates of fuel-type and thermal-type NOx，along with the enhancement of De-NOx reactions.Overall，a steam blending ratio of H=0.1 is recommended for 0.2＜C＜0.4，whereas H=0.2 is preferred for C＞0.4.关键词：cracked ammonia combustion;swirl combustion;steam addition;NOx;plane laserinduced fluorescence19|8|0更新时间：2026-07-09
Special Topic Preparation of High-Purity Gas
摘要：To meet the increasing demand for electronic-grade ultra-pure nitrogen and to minimize energy consumption during production of such nitrogen via cryogenic air separation，cryogenic air separation process models were developed using Aspen Plus，and a multi-obj ective optimization analysis was conducted.Firstly，the simulation results of two nitrogen production processes were compared under equivalent nitrogen product specifications.Secondly，based on the superior performance of the dual-column process with gas extraction from the low-pressure column（LPC），the sensitivity of specific power consumption to four design variables—separation pressure of the high-pressure column（HPC），separation pressure of the LPC，and the number of theoretical stages in both columns—was investigated using the Box-Behnken response surface methodology. The interactions between these design variables and their effects on specific power consumption were analyzed，and predictive models relating the design variables to four response variables were established.An optimal parameter combination was subsequently identified，followed by a comparative exergy analysis between the optimized and initial conditions.The results indicate that the predictive models exhibit high accuracy，with a relative error of only 0.02% between the predicted and simulated values under optimal parameter combination. Most of the exergy destruction comes from the air compression unit，distillation unit，and main heat exchanger. After optimization，nitrogen production increased by 7.30%，specific power consumption decreased by 3.74%，and exergy destruction per unit of nitrogen production was reduced by 6.33%.Consequently，the system exergy efficiency was enhanced from 45.13% to 47.05%.关键词：cryogenic air separation system;response surface methodology;exergy analysis34|9|0更新时间：2026-07-09- 摘要：To address the challenge that single-type electrolyzer arrays struggle to balance economic viability with operational flexibility under wide power fluctuations，a wind-solar coupled hydrogen production system based on the synergy of hybrid electrolyzer arrays is proposed.By leveraging the complementary characteristics of different electrolyzers to obtain complementary benefits，a bi-level multi-obj ective optimization strategy for the system is established.In the upper level，a non-dominated sorting genetic algorithm is employed to perform multi-obj ective optimization for macro-level capacity allocation.In the lower level，a bi-level mixed-integer linear programming（MILP）model is formulated，consisting of an aggregation model for the rapid evaluation of upper-level configurations and a refined model to accurately characterize the operational dynamics of each electrolyzer unit.The results show that，the proposed optimization scheme reduces the unit hydrogen production cost by 14.9% relative to conventional sequential start-stop strategies and by 22.0% relative to periodic rotation strategies，significantly enhancing the economic efficiency of the system.Moreover，the system demonstrates excellent long-term operational adaptability.Under seasonal transitions and fluctuating hydrogen demands，the maximum seasonal increase in unit hydrogen production cost is controlled within 11.16%.Furthermore，compared with the steady demand scenario，the proposed strategy further reduces the hydrogen production cost by 3.93%—7.98% through flexible regulation，effectively overcoming the impacts of long-term fluctuations.These findings are intended to provide a feasible solution for achieving both high efficiency and flexibility in renewable energy-based hydrogen production.关键词：renewable energy-based hydrogen production;hybrid electrolyzer arrays;wind-solar coupling;capacity allocation;bi-level multi-obj ective optimization63|14|0更新时间：2026-07-09
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摘要：As China's “Carbon Peaking and Carbon Neutrality”goals progress，the traditional“heat-led”operation mode of combined heat and power systems has been found insufficient to meet the requirements of new power systems for unit flexibility and deep peak-shaving capacity.There is an urgent need to rely on thermoelectric decoupling technologies to enhance high-efficiency heating and load regulation capabilities of the systems.Although research on thermoelectric decoupling has intensified in recent years，most studies focus on single cases or localized technologies with inconsistent system boundaries，parameter settings，and evaluation systems，making it difficult to establish a comparable and generalizable research framework.In this paper，based on the unified thermal modeling framework of EBSILON software，the system configurations，steam extraction methods，and electrothermal coupling mechanisms of typical flexibility retrofitting technologies—including low-temperature heat source extraction，low pressure cylinder near zero output，high back pressure heating，and solar-assisted thermopower— are systematically reviewed. Under a unified modeling logic and evaluation index system，quantitative comparative analyses of thermal efficiency，heating capacity，coal consumption，and off-design performance are conducted for various schemes，and the common laws and differentiated characteristics of different technical pathways are summarized.Furthermore，shortcomings in current research regarding model consistency，working condition coverage，and engineering applicability are identified.Three maj or directions for future thermoelectric decoupling research are proposed：strengthening dynamic behavior simulation and closed-loop control verification；expanding analysis across multiple boundaries for extreme and uncertain scenarios；and developing multi-technology coupling and life-cycle optimization.The findings are intended to provide a structured theoretical basis and methodological support for the quantitative evaluation，engineering selection，and operational optimization of flexibility retrofits of CHP units.关键词：EBSILON;combined heat and power;high back pressure heating;low pressure cylinder near zero output;complementary heating using coal and solar energy21|9|0更新时间：2026-07-09- 摘要：Because the windshield of electric vehicles（EVs）tends to fog under very humid conditions，compromising driving safety，a control strategy for the supply of low-humidity air was proposed to accelerate the dynamic dehumidification response of the EV's indirect thermal management systems during a switch to dehumidification mode.An experimental platform for transcritical CO2 systems was built up，and a dynamic simulation model with high precision was developed.Based on the results from this simulation model，performance differences between direct and indirect systems were compared to reveal the hysteresis mechanism of the dynamic dehumidification response in indirect systems.The effects of the liquid-cooled evaporator（LCEVP）flow rate，liquid-cooled gas cooler（LCGC）flow rate，and front air volume on the dynamic dehumidification capacity were analyzed，leading to the proposal of an optimal control strategy based on timesequenced collaboration.The results show that due to the thermal inertia of the water circuit，the time required for the air supply temperature to reach the dew point is prolonged，and a temperature rebound occurs，leading to an increase in dehumidification air temperature.Consequently，the dynamic cumulative dehumidification capacity of the indirect system was found to be 59.8% lower than that of the direct system.By adjusting the LCGC flow rate and front air volume to 4.8 L/min and 0 m3/h，respectively，the dynamic cumulative dehumidification capacity was increased by 90.9% and 77.9%.Furthermore，by optimizing the time sequence to adjust the LCEVP flow rate，LCGC flow rate，and front air volume at the moment of switching，it was observed that adjusting the LCEVP flow rate and front air volume 8s and 30 s after the switch，respectively，increased the cumulative dehumidification capacity by 203.1% compared to the original scheme.This optimized performance exceeded that of the direct system by 22.2%，significantly enhancing the rapid low-humidity air supply capability under defogging conditions.These findings offer effective strategic guidance for rapid dynamic dehumidification responses in practical applications of indirect thermal management systems.关键词：electric vehicle thermal management;transcritical CO2 system;Indirect system;dehumidification dynamic response17|8|0更新时间：2026-07-09
- 摘要：To mitigate the negative effects of casing treatment on the performance of modern turbocharger centrifugal compressors，a j oint optimization method that integrates the centrifugal impeller with casing treatment across multiple working points is developed.First，by analyzing the principal geometric parameters affecting compressor performance，an integrated parameterization of the casing treatment，casing meridional profile，and impeller blade angle distribution was established. Then，integrated and joint optimization of geometric parameters of the compressor impeller and casing treatment was performed using a data-driven automated optimization method.Based on the optimized designs，the coupling mechanism between casing treatment and the impeller was analyzed，and the flow field characteristics of high-efficiency designs were summarized.Results show that，compared with the baseline impeller-casing treatment model，the optimized compressor exhibits increases in total pressure ratio of 4.55%，4.97%，and 3.70%，and increases in adiabatic efficiency of 5.04%，5.46%，and 5.52% at three target working points，respectively，without a reduction in the stable operating range.The compressor's high-efficiency region was expanded and shifted toward the target working points.The optimized compressor yielded a 1.68% improvement in the thermal efficiency of the internal combustion engine.Applying casing treatment solely as a flow-stabilization measure without joint optimization with the impeller was found to cause additional performance losses.The primary flow mechanism responsible for performance improvement was identified as a rear-loaded blade-tip loading distribution，which reduces leading-edge suction and mitigates the adverse pressure gradient on the pressure side.关键词：turbocharger;centrifugal compressor;casing treatment;multiple working points;integrated and j oint design optimization;flow mechanism32|7|0更新时间：2026-07-09
- 摘要：To address the lack of multiphysics coupled numerical evaluation methods and the unclear influence law of parameters on the static and dynamic characteristics of CO2 gas foil bearings（GFBs），a sensitivity analysis was conducted on the foil geometrical parameters of the third-generation bump-type CO2 GFBs.Based on a full three-dimensional（3 D）unsteady conj ugate heat transfer（CHT）method，a mathematical model for the convective heat transfer between the GFB gas film and the shaft and top foil was developed.Through the coupled solution of the Reynolds equation，the 3D energy equation，and the 3D structural heat conduction equations for the shaft and bearing，a multiphysics coupled numerical prediction method for the static and dynamic characteristics of the third-generation bump-type CO2 GFBs was developed.The numerical method is validated against experimental data for the load-carrying capacity（LCC），dynamic stiffness，and damping coefficients of air-lubricated GFBs.Subsequently，a sensitivity analysis on foil geometrical parameters—including the bump foil's height，half-length，and thickness，as well as the top foil' s thickness—was performed using the central composite design（CCD）method.The static and dynamic characteristics under high-temperature and high-pressure conditions（315 ℃，2.0 Pa）were calculated for 25 foil geometrical parameter combinations.Main effect diagrams were obtained with static load，direct stiffness，and the energy dissipation factor as responses.The calculation results indicate that the static load and direct stiffness increase as the bump foil's height increases and the bump foil's half-length decreases.At an eccentricity ratio ofε=0.5，the static load and direct stiffness initially increase and then decrease with increasing bump foil thickness，peaking at thickness levels of 30% and 20%，respectively.Under heavy-load conditions（ε=0.8），both static load and direct stiffness are most sensitive to the bump foil's thickness，with influence magnitudes of 35.1% and 76.4%，respectively.Since the regulation laws of foil geometrical parameters on two kinds of performance indicators exhibit inverse coupling characteristics，multi-objective optimization with direct stiffness and the energy dissipation factor as responses should be implemented to obtain foil geometrical parameters that make the overall dynamic performance of GFBs optimal.The findings serve as a reference for the performance analysis and structural design of the third-generation bump-type CO2 GFBs.关键词：third-generation bump-type CO2 GFB;static characteristics;dynamic characteristics;multiphysics coupled numerical prediction method16|9|0更新时间：2026-07-09
- 摘要：To elucidate how different stack materials influence the performance of thermoacoustic engines，a high-accuracy numerical simulation model for thermoacoustic engines utilizing the discontinuous Galerkin method was developed based on the open-source C++ library MFEM. The impacts of four different stack materials on the energy conversion process and efficiency of thermoacoustic engines were investigated.Energy distribution and particle oscillation characteristics were analyzed from both Eulerian and Lagrangian perspectives. The results demonstrate that the highest pressure amplitude was generated by the iron stack，while the lowest was produced by the copper stack.The temperature gradient distribution was found to be significantly dependent on material properties：a uniform distribution was observed in the iron stack，a nearly horizontal profile in the copper stack，and a concentration near the hot-end heat exchanger in the glass and Kapton stacks.In the Eulerian framework，the local energy density distribution was found to be consistent with the temperature gradient patterns.In the Lagrangian framework，the distribution patterns of particles at different positions working over one cycle were elucidated through temperature-position and temperature-specific entropy curves of particles.Further calculations showed that the glass stack yielded the maximum cycle work while the copper stack yielded the minimum；the copper stack exhibited the highest heat transfer，whereas the iron stack showed the lowest；and the iron stack attained the highest efficiency（10.11%），while the copper stack presented the lowest（3.87%）. These findings indicate that the variations in temperature gradient distribution，governed by the physical properties of the stack materials，are a key factor determining the energy conversion efficiency of thermoacoustic engines.关键词：thermoacoustic engine;stack;energy conversion;discontinuous Galerkin method40|11|0更新时间：2026-07-09
- 摘要：To achieve both image privacy protection and high-fidelity reconstruction at ultra-low bitrates，a structure-semantics-residual collaborative image compression framework is proposed. In this framework，representations are extracted from three distinct levels（i.e.，image structure，semantics and residual）：structural information is captured via edge maps for backbone compression；semantic priors are derived from image captions with mutual information removed；and residual signals containing sensitive region information are transmitted via a trusted channel.At the decoder，de-identified images are generated by integrating edge maps with semantic information，while original high-fidelity images are restored using edge maps and residual signals，thereby achieving synergistic optimization of privacy protection and visual fidelity.Results demonstrate that through the comparative experiments on the CLIC（Challenge on Learned Image Compression）dataset，the proposed method reduces bitrate by 13%—32% while maintaining high-quality reconstruction. Additionally，branch-wise generation of de-identified images is supported.Furthermore，the effectiveness of the individual branches and constraint mechanisms is verified through ablation experiments，indicating that a reasonable trade-off between privacy protection and image reconstruction quality is realized by the proposed framework.关键词：image compression;ultra-low bitrate;privacy protection;high-fidelity14|12|0更新时间：2026-07-09
- 摘要：To address the limitations of existing graph neural network-based knowledge graph representation learning methods in distinguishing diverse entity semantics and handling relations homogeneously during embedding learning，a novel knowledge graph representation learning method based on semantic discrimination and subgraph integration is proposed. Hierarchical modeling is employed to learn entity representations by progressively mining structural information from the graph.In the semantic discrimination module，multiple relation-aware subgraphs are constructed and their semantic information is integrated to capture comprehensive entity attributes. In the subgraph integration module，the importance of different subgraphs is evaluated，and selective neighborhood aggregation is performed to preserve discriminative semantic features. Additionally，knowledge graph triples are modeled via an encoder for link prediction tasks，and a cross-entropy loss function is introduced during model training to effectively integrate semantic and structural information.Experimental results on three standard datasets demonstrate that the proposed method yields comprehensive performance improvements over current state-of-the-art models. Specifically，on the FB15 K-237 dataset，improvements of 2.42%，3.90%，and 1.44% were achieved in mean reciprocal rank（MRR），Hits@3，and Hits@10（denoting the proportion of queries with the correct answer in the topk predictions（k=3，10））respectively.On the YAGO3-10 dataset，the MRR，Hits@3，and Hits@10 were improved by 2.17%，4.81%，and 2.01%，respectively.On the WN18 RR dataset，increases of 0.61%，0.59%，and 0.86% were observed in the corresponding metrics.The superiority of the proposed method is thus validated.关键词：knowledge graph;representation learning;graph neural networks;link prediction19|19|0更新时间：2026-07-09
- 摘要：To address the issues of inefficient performance analysis and difficulty in tuning caused by the scarcity of input/output（I/O）data and the prohibitive costs of modeling and optimization in large-scale parallel applications，a novel method for machine learning-driven I/O performance modeling and prediction in large-scale parallel applications is proposed.During the modeling phase，on the one hand，a linear regression-based model for I/O feature prediction in parallel applications is constructed using data sampled from small-scale node environments to enable the extrapolation of features to large-scale configurations；on the other hand，I/O features in parallel applications acquired from small-scale node environments，along with the corresponding I/O stack parameter space，are fed into an artificial neural network（ANN）for training.This allows for the learning of the nonlinear mapping between system configuration parameters and I/O performance，leading to the construction of a model for I/O performance prediction in parallel applications. During the prediction phase，the I/O features of large-scale parallel applications are first predicted via the I/O feature prediction model.These predicted features，together with the corresponding I/O stack parameter space of large-scale parallel applications，are then fed into the I/O performance prediction model to accurately predict the I/O performance of such applications.Experimental results demonstrate that，on a domestic supercomputer，the proposed method exhibits high prediction accuracy across four benchmark applications：IOR，S3D-IO，BT-IO，and Flash-IO.When models trained on 1—16 nodes are extrapolated to a 128-node（2048-process）scenario，the mean absolute percentage errors（MAPEs）are 19.07%，18.96%，12.34%，and 14.16%，respectively.Furthermore，by tuning the I/O stack parameters based on the proposed model，I/O performance speedups of 16.38，23.16，45.36，and 65.38-fold are achieved for the four benchmark applications.关键词：large-scale parallel applications;I/O performance modeling;I/O auto-tuning;artificial neural network47|14|0更新时间：2026-07-09
- 摘要：To address the engineering challenge of degraded long-term stability of anti-corona systems for large air-cooled generator stator bars at high altitudes，the stator bars of an 18 kV air-cooled generator were investigated.Systematic research on the evolutionary law of anti-corona performance for stator bars at high altitudes was conducted.A characterization method for the anti-aging performance of anti-corona materials based on electrothermal coupling aging tests was proposed.Various simulated samples were screened and prepared using the analytic hierarchy process（AHP），and the optimal anti-corona material was selected through a long-term electrothermal aging test for 2000 h.Furthermore，a nonlinear resistivity model of anti-corona materials under electrothermal coupling was constructed.Based on blackbody radiation correction theory，a high-precision bidirectional coupling solution method for the electrothermal multiphysics field of stator bars was developed，and the steady-state and transient electrothermal characteristics were numerically simulated using the COMSOL finite element method. Experimental results demonstrate that in high-altitude correction tests，the temperature rise of stator bars increased significantly. Compared with low-altitude conditions，the maximum temperature measured during the corona onset voltage test increased by 74.9%，whereas the maximum electric field strength increased by 11.9%，indicating that the temperature rise was substantially larger than the change in electric field strength.The relative error between the simulation results and experimental data was observed to be less than 5%，verifying the accuracy of the proposed model and solution method.This research provides a theoretical basis and serves as an engineering reference for the optimal design of anti-corona systems used in air-cooled generators at high and ultra-high altitudes.关键词：air-cooled generator;electrothermal aging;finite element analysis;bidirectional coupling;anti-corona performance13|8|0更新时间：2026-07-09
- 摘要：To address the limitations of traditional finite element methods（FEM）in transformer winding temperature evaluation，such as high computational costs，slow solution speeds，and poor suitability for engineering applications，a fast calculation method for steady-state thermal flow fields in transformers is proposed based on a physics-informed deep operator network（PI-DeepONet）.This method achieves high-precision and high-efficiency calculation of thermal flow fields.The distribution characteristics of the thermal flow fields in transformer windings under various operating conditions were obtained via numerical simulations，and a high-quality dataset was constructed.By integrating the DeepONet architecture with physical constraints，a network comprising branch and trunk components was designed.The heat conduction and fluid continuity equations were incorporated into the loss function as physical constraints，enabling accurate prediction of the steady-state thermal flow field in transformer windings.Calculation case results demonstrate that under a hyperparameter configuration featuring a 7-layer depth，a 50-unit width，a learning rate of 0.01，a Tanh activation function，and the Adam optimizer，the mean absolute errors（MAE）for temperature，pressure，and radial/axial flow velocities are 0.1 ℃，5.03 Pa，0.0061 m/s，and 0.0036 m/s，respectively.Relative errors for over 95% of the nodes are below 0.7%.Furthermore，a single prediction takes only 0.12 s，representing a speedup of approximately 10000 times compared to Fluent-based numerical simulations. The proposed method significantly enhances computational efficiency while maintaining prediction accuracy of the thermal flow fields，supporting the rapid simulation requirements of thermal management and digital twin applications for transformers.关键词：deep operator network;physical information;power transformer;thermal flow field16|4|0更新时间：2026-07-09
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