Swing nose crossings(SNXs)have been widely used in heavy haul railways to create a smoother load transfer and hence reduced impact load.However,the current design of SNXs hasn’t been fully examined under heavy haul o...Swing nose crossings(SNXs)have been widely used in heavy haul railways to create a smoother load transfer and hence reduced impact load.However,the current design of SNXs hasn’t been fully examined under heavy haul operating conditions.Additionally,maintenance guidelines for SNX wear-related issues in Australian heavy haul railways are relatively lacking.As such,this study aims to investigate the dynamic response of the wheel-rail contact and analyse the wear performance of an SNX currently used in Australian heavy haul railways.Dynamic implicit-explicit finite element analysis was conducted to simulate the wheel-rail contact along the SNX.The distribution of the wear intensity over the SNX was identified by using a local contact-based wear model.The influence of various scenarios on wear was also explored.The results verify the improved dynamic performance of the SNX,as the increased contact force after load transfer remains below 1.2 times the static load.The findings also indicate that the decrease in relative height and increase in nose rail inclination result in greater wear on the nose rail.Notably,the SNX considered in the current study exhibits better wear performance when used with moderately worn wheels.展开更多
In this study,a novel synergistic swing energy-regenerative hybrid system(SSEHS)for excavators with a large inertia slewing platform is constructed.With the SSEHS,the pressure boosting and output energy synergy of mul...In this study,a novel synergistic swing energy-regenerative hybrid system(SSEHS)for excavators with a large inertia slewing platform is constructed.With the SSEHS,the pressure boosting and output energy synergy of multiple energy sources can be realized,while the swing braking energy can be recovered and used by means of hydraulic energy.Additionally,considering the system constraints and comprehensive optimization conditions of energy efficiency and dynamic characteristics,an improved multi-objective particle swarm optimization(IMOPSO)combined with an adaptive grid is proposed for parameter optimization of the SSEHS.Meanwhile,a parameter rule-based control strategy is designed,which can switch to a reasonable working mode according to the real-time state.Finally,a physical prototype of a 50-t excavator and its AMESim model is established.The semi-simulation and semi-experiment results demonstrate that compared with a conventional swing system,energy consumption under the 90°rotation condition could be reduced by about 51.4%in the SSEHS before parameter optimization,while the energy-saving efficiency is improved by another 13.2%after parameter optimization.This confirms the effectiveness of the SSEHS and the IMOPSO parameter optimization method proposed in this paper.The IMOPSO algorithm is universal and can be used for parameter matching and optimization of hybrid power systems.展开更多
This study delves into the optimization of the methanol-vinyl acetate(VAC)azeotrope separation process via pressure swing distillation(PSD),along with an evaluation of its energy-saving potential.The methanol-VAC syst...This study delves into the optimization of the methanol-vinyl acetate(VAC)azeotrope separation process via pressure swing distillation(PSD),along with an evaluation of its energy-saving potential.The methanol-VAC system,a polar azeotro pe highly susceptible to pressure variations,presents notable separation complexities in polyvinyl alcohol production.Aspen Plus simulations were utilized to assess the feasibility of PSD,with particular emphasis on critical process parameters such as the number of theoretical plates,feed position,reflux ratio,and sidestream extraction location.The results indicate that PSD demonstrates remarkable efficacy in separating methanol and VAC,achieving purities of 99.88%and 99.73%respectively.When compared to extractive distillation,PSD achieves a reduction of 9.07 t·h^(-1)in steam consumption and minimizes wastewater generation by 20.77 t·h^(-1).Furthermore,the economic assessment reveals a 7.91%decrease in the total annual cost associated with PSD.This study not only provides theoretical insights but also offers practical guidance for the design of energyefficient and sustainable separation processes.Future research will focus on extending the analysis to encompass multi-pressure scenarios,further enhancing the applicability and robustness of the findings.展开更多
基金supported by Australia Research Council through the Linkage Project(Grant No.LP200100110).
文摘Swing nose crossings(SNXs)have been widely used in heavy haul railways to create a smoother load transfer and hence reduced impact load.However,the current design of SNXs hasn’t been fully examined under heavy haul operating conditions.Additionally,maintenance guidelines for SNX wear-related issues in Australian heavy haul railways are relatively lacking.As such,this study aims to investigate the dynamic response of the wheel-rail contact and analyse the wear performance of an SNX currently used in Australian heavy haul railways.Dynamic implicit-explicit finite element analysis was conducted to simulate the wheel-rail contact along the SNX.The distribution of the wear intensity over the SNX was identified by using a local contact-based wear model.The influence of various scenarios on wear was also explored.The results verify the improved dynamic performance of the SNX,as the increased contact force after load transfer remains below 1.2 times the static load.The findings also indicate that the decrease in relative height and increase in nose rail inclination result in greater wear on the nose rail.Notably,the SNX considered in the current study exhibits better wear performance when used with moderately worn wheels.
基金supported by the Changsha Major Science and Technology Plan Project,China(No.kq2207002)the Natural Science Foundation of Hunan Province(No.2023JJ40720)the Postgraduate Innovative Project of Central South University,China(No.2022XQLH058)。
文摘In this study,a novel synergistic swing energy-regenerative hybrid system(SSEHS)for excavators with a large inertia slewing platform is constructed.With the SSEHS,the pressure boosting and output energy synergy of multiple energy sources can be realized,while the swing braking energy can be recovered and used by means of hydraulic energy.Additionally,considering the system constraints and comprehensive optimization conditions of energy efficiency and dynamic characteristics,an improved multi-objective particle swarm optimization(IMOPSO)combined with an adaptive grid is proposed for parameter optimization of the SSEHS.Meanwhile,a parameter rule-based control strategy is designed,which can switch to a reasonable working mode according to the real-time state.Finally,a physical prototype of a 50-t excavator and its AMESim model is established.The semi-simulation and semi-experiment results demonstrate that compared with a conventional swing system,energy consumption under the 90°rotation condition could be reduced by about 51.4%in the SSEHS before parameter optimization,while the energy-saving efficiency is improved by another 13.2%after parameter optimization.This confirms the effectiveness of the SSEHS and the IMOPSO parameter optimization method proposed in this paper.The IMOPSO algorithm is universal and can be used for parameter matching and optimization of hybrid power systems.
基金financial support from the National Key Research and Development Program of China(2022YFC2106300)the National Nature Science Foundation of China(U2267226)。
文摘This study delves into the optimization of the methanol-vinyl acetate(VAC)azeotrope separation process via pressure swing distillation(PSD),along with an evaluation of its energy-saving potential.The methanol-VAC system,a polar azeotro pe highly susceptible to pressure variations,presents notable separation complexities in polyvinyl alcohol production.Aspen Plus simulations were utilized to assess the feasibility of PSD,with particular emphasis on critical process parameters such as the number of theoretical plates,feed position,reflux ratio,and sidestream extraction location.The results indicate that PSD demonstrates remarkable efficacy in separating methanol and VAC,achieving purities of 99.88%and 99.73%respectively.When compared to extractive distillation,PSD achieves a reduction of 9.07 t·h^(-1)in steam consumption and minimizes wastewater generation by 20.77 t·h^(-1).Furthermore,the economic assessment reveals a 7.91%decrease in the total annual cost associated with PSD.This study not only provides theoretical insights but also offers practical guidance for the design of energyefficient and sustainable separation processes.Future research will focus on extending the analysis to encompass multi-pressure scenarios,further enhancing the applicability and robustness of the findings.
