Calculations of the impact of friction and wear on energy consumption,economic expenditure,and CO2 emissions are presented on a global scale.This impact study covers the four main energy consuming sectors:transportati...Calculations of the impact of friction and wear on energy consumption,economic expenditure,and CO2 emissions are presented on a global scale.This impact study covers the four main energy consuming sectors:transportation,manufacturing,power generation,and residential.Previously published four case studies on passenger cars,trucks and buses,paper machines and the mining industry were included in our detailed calculations as reference data in our current analyses.The following can be concluded:-In total,～23％ (119 EJ) of the world's total energy consumption originates from tribological contacts.Of that 20％ (103 EJ) is used to overcome friction and 3％ (16 EJ) is used to remanufacture worn parts and spare equipment due to wear and wear-related failures.-By taking advantage of the new surface,materials,and lubrication technologies for friction reduction and wear protection in vehicles,machinery and other equipment worldwide,energy losses due to friction and wear could potentially be reduced by 40％ in the long term (15 years)and by 18％ in the short term (8 years).On global scale,these savings would amount to 1.4％ of the GDP annually and 8.7％ of the total energy consumption in the long term.-The largest short term energy savings are envisioned in transportation (25％) and in the power generation (20％) while the potential savings in the manufacturing and residential sectors are estimated to be ～10％.In the longer terms,the savings would be 55％,40％,25％,and 20％,respectively.-Implementing advanced tribological technologies can also reduce the CO2 emissions globally by as much as 1,460 MtCO2 and result in 450,000 million Euros cost savings in the short term.In the longer term,the reduction can be 3,140 MtCO2 and the cost savings 970,000 million Euros.Fifty years ago,wear and wear-related failures were a major concern for UK industry and their mitigation was considered to be the major contributor to potential economic savings by as much as 95％ in ten years by the development and deployment of new展开更多
Turbulent boundary layer control(TBLC) for skin-friction drag reduction is a relatively new technology made possible through the advances in computational-simulation capabilities,which have improved the understanding ...Turbulent boundary layer control(TBLC) for skin-friction drag reduction is a relatively new technology made possible through the advances in computational-simulation capabilities,which have improved the understanding of the flow structures of turbulence.Advances in micro-electronic technology have enabled the fabrication of active device systems able to manipulating these structures.The combination of simulation,understanding and micro-actuation technologies offers new opportunities to significantly decrease drag,and by doing so,to increase fuel efficiency of future aircraft.The literature review that follows shows that the application of active control turbulent skin-friction drag reduction is considered of prime importance by industry,even though it is still at a low technology readiness level(TRL).This review presents the state of the art of different technologies oriented to the active and passive control for turbulent skin-friction drag reduction and contributes to the improvement of these technologies.展开更多
The use of bionic non-smooth surfaces is a popular approach for saving energy because of their drag reduction property. Conventional non-smooth structures include riblets and dimples. Inspired by sand dunes, a novel v...The use of bionic non-smooth surfaces is a popular approach for saving energy because of their drag reduction property. Conventional non-smooth structures include riblets and dimples. Inspired by sand dunes, a novel variable ovoid non-smooth structure is proposed in this study. The body of the variable ovoid dimple was designed based on three size parameters, the radius, semimajor, and depth, and a 3D model was created based on UG software. The constructed variable dimples were placed in a rectangular array on the bottom of a square tube model. Following ANSYS meshing, the grid model was imported into FLUENT, where the flow characteristics were calculated. Results of skin friction reduction were achieved and the effect of the design parameters on different variable ovoid dimples was obtained by orthogonal testing. Various aspects of the skin friction reduction mechanism were discussed including the distribution of velocity vectors, variation in boundary layer thickness, and pressure distribution.展开更多
文摘Calculations of the impact of friction and wear on energy consumption,economic expenditure,and CO2 emissions are presented on a global scale.This impact study covers the four main energy consuming sectors:transportation,manufacturing,power generation,and residential.Previously published four case studies on passenger cars,trucks and buses,paper machines and the mining industry were included in our detailed calculations as reference data in our current analyses.The following can be concluded:-In total,～23％ (119 EJ) of the world's total energy consumption originates from tribological contacts.Of that 20％ (103 EJ) is used to overcome friction and 3％ (16 EJ) is used to remanufacture worn parts and spare equipment due to wear and wear-related failures.-By taking advantage of the new surface,materials,and lubrication technologies for friction reduction and wear protection in vehicles,machinery and other equipment worldwide,energy losses due to friction and wear could potentially be reduced by 40％ in the long term (15 years)and by 18％ in the short term (8 years).On global scale,these savings would amount to 1.4％ of the GDP annually and 8.7％ of the total energy consumption in the long term.-The largest short term energy savings are envisioned in transportation (25％) and in the power generation (20％) while the potential savings in the manufacturing and residential sectors are estimated to be ～10％.In the longer terms,the savings would be 55％,40％,25％,and 20％,respectively.-Implementing advanced tribological technologies can also reduce the CO2 emissions globally by as much as 1,460 MtCO2 and result in 450,000 million Euros cost savings in the short term.In the longer term,the reduction can be 3,140 MtCO2 and the cost savings 970,000 million Euros.Fifty years ago,wear and wear-related failures were a major concern for UK industry and their mitigation was considered to be the major contributor to potential economic savings by as much as 95％ in ten years by the development and deployment of new
基金supported by the European Commission though the Research and Innovation action DRAGY(Grant No.690623)the Ministry of Industry and Information Technology(MIIT)of the Chinese government
文摘Turbulent boundary layer control(TBLC) for skin-friction drag reduction is a relatively new technology made possible through the advances in computational-simulation capabilities,which have improved the understanding of the flow structures of turbulence.Advances in micro-electronic technology have enabled the fabrication of active device systems able to manipulating these structures.The combination of simulation,understanding and micro-actuation technologies offers new opportunities to significantly decrease drag,and by doing so,to increase fuel efficiency of future aircraft.The literature review that follows shows that the application of active control turbulent skin-friction drag reduction is considered of prime importance by industry,even though it is still at a low technology readiness level(TRL).This review presents the state of the art of different technologies oriented to the active and passive control for turbulent skin-friction drag reduction and contributes to the improvement of these technologies.
基金Project supported by the National Natural Science Foundation of China （No. 51375439）
文摘The use of bionic non-smooth surfaces is a popular approach for saving energy because of their drag reduction property. Conventional non-smooth structures include riblets and dimples. Inspired by sand dunes, a novel variable ovoid non-smooth structure is proposed in this study. The body of the variable ovoid dimple was designed based on three size parameters, the radius, semimajor, and depth, and a 3D model was created based on UG software. The constructed variable dimples were placed in a rectangular array on the bottom of a square tube model. Following ANSYS meshing, the grid model was imported into FLUENT, where the flow characteristics were calculated. Results of skin friction reduction were achieved and the effect of the design parameters on different variable ovoid dimples was obtained by orthogonal testing. Various aspects of the skin friction reduction mechanism were discussed including the distribution of velocity vectors, variation in boundary layer thickness, and pressure distribution.
