The cooling performance of air-cooled condenser(ACC)is susceptible to adverse impacts of ambient winds.In this work,three kinds of lateral double-layered deflectors installed under the ACC platform are proposed to wea...The cooling performance of air-cooled condenser(ACC)is susceptible to adverse impacts of ambient winds.In this work,three kinds of lateral double-layered deflectors installed under the ACC platform are proposed to weaken the unfavorable effects of cross winds.Through CFD simulation methods,the main parameters of thermo-flow performances of a 2×660 MW direct dry cooling system are obtained,by which it can be concluded that the deflectors can effectively reduce the inlet air temperatures while enhance the mass flow rates of upwind fans due to the guiding effect,especially at high wind speeds,while the improvement of cooling capacity of ACCs in the 0°wind direction is weak.The inclined-vertical deflectors are superior to others in performance improvement of ACCs for all cases,which can reduce the turbine back pressure by 12.15%when the wind speed is 12 m/s,so they can be applied to the performance enhancement of ACCs under windy conditions in practical engineering.展开更多
With the development of economy and the progress of medical science and technology,artificial prosthesis replacement has become an important means to improve the dysfunction caused by human bone diseases.However,there...With the development of economy and the progress of medical science and technology,artificial prosthesis replacement has become an important means to improve the dysfunction caused by human bone diseases.However,there are still some loose phenomena caused by stress shielding.To solve the complications of aseptic loosening after calcaneal prosthesis replacement,an optimal design method for the prosthesis was proposed.The prosthesis was designed and optimized according to the real bone shape and the replacement requirements by the combination of computed tomography(CT)technology,computer-aided design,finite element analysis,and power flow theory.CT data were imported into MIMICS and Geomagic Studios.UG was used to obtain the geometric model of the human skeleton.Then,the 3D finite element model of the prosthesis was established by combining the finite element software Abaqus,and a series of finite element analysis was carried out.The prosthesis was topologically optimized and filled with a porous structure.The prosthesis was implanted by computer simulation.Finally,the power flow method was used to compare the dynamic performance and energy transfer before and after the prosthesis replacement to verify the rationality of the prosthesis design.In this paper,this method was used to optimize the design of the calcaneal prosthesis,and the research shows that this method can reduce the stress shielding effect of the calcaneal prosthesis.From the case of calcaneal prosthesis optimization,this method is not only a supplement to the contemporary biomechanical theory but also can guide the design of bone prosthesis in bone prosthesis replacement surgery.展开更多
基金The National Natural Science Foundation of China(Grant No.51476055,51821004)the National Basic Research Program of China(Grant No.2015CB251503)the Fundamental Research Funds for the Central Universities(Grant No.2018QN036)are gratefully acknowledged for supporting this research.
文摘The cooling performance of air-cooled condenser(ACC)is susceptible to adverse impacts of ambient winds.In this work,three kinds of lateral double-layered deflectors installed under the ACC platform are proposed to weaken the unfavorable effects of cross winds.Through CFD simulation methods,the main parameters of thermo-flow performances of a 2×660 MW direct dry cooling system are obtained,by which it can be concluded that the deflectors can effectively reduce the inlet air temperatures while enhance the mass flow rates of upwind fans due to the guiding effect,especially at high wind speeds,while the improvement of cooling capacity of ACCs in the 0°wind direction is weak.The inclined-vertical deflectors are superior to others in performance improvement of ACCs for all cases,which can reduce the turbine back pressure by 12.15%when the wind speed is 12 m/s,so they can be applied to the performance enhancement of ACCs under windy conditions in practical engineering.
基金the Natural Youth Science Foundation of Fujian Province(No.2017J05006)the National Natural Science Foundation of China(No.51575196)+1 种基金the Subsidized Project for Postgraduates’Innovation Fund in Scientific Research of Huaqiao University(Nos.18014080034 and 19013080038)the Case Base of Graduate Programs for Professional Degree of Huaqiao University(No.18YJG25)。
文摘With the development of economy and the progress of medical science and technology,artificial prosthesis replacement has become an important means to improve the dysfunction caused by human bone diseases.However,there are still some loose phenomena caused by stress shielding.To solve the complications of aseptic loosening after calcaneal prosthesis replacement,an optimal design method for the prosthesis was proposed.The prosthesis was designed and optimized according to the real bone shape and the replacement requirements by the combination of computed tomography(CT)technology,computer-aided design,finite element analysis,and power flow theory.CT data were imported into MIMICS and Geomagic Studios.UG was used to obtain the geometric model of the human skeleton.Then,the 3D finite element model of the prosthesis was established by combining the finite element software Abaqus,and a series of finite element analysis was carried out.The prosthesis was topologically optimized and filled with a porous structure.The prosthesis was implanted by computer simulation.Finally,the power flow method was used to compare the dynamic performance and energy transfer before and after the prosthesis replacement to verify the rationality of the prosthesis design.In this paper,this method was used to optimize the design of the calcaneal prosthesis,and the research shows that this method can reduce the stress shielding effect of the calcaneal prosthesis.From the case of calcaneal prosthesis optimization,this method is not only a supplement to the contemporary biomechanical theory but also can guide the design of bone prosthesis in bone prosthesis replacement surgery.
