The Polar Regions are rich in natural resources but experience an extremely cold climate.The surfaces of offshore platforms operating in the Polar Regions are prone to icing.To develop solutions to this problem of sur...The Polar Regions are rich in natural resources but experience an extremely cold climate.The surfaces of offshore platforms operating in the Polar Regions are prone to icing.To develop solutions to this problem of surface icing,the influence of both the liquid water concentration of the surrounding atmosphere and the average water droplet diameter on the formation of ice on two major structural components of offshore platforms was analyzed using a combination of Fluent and FENSAP-ICE.Results showed that at a wind speed of 7 m/s,as the concentration of liquid water in the air increases from 0.05 to 0.25 g/m3,the amount and thickness of the icing on the surfaces of the two structural components increase linearly.At a wind speed of 7 m/s and when the size of the average water droplet diameter is 20–30(30–35)μm,as the average water droplet diameter increases,the amount and thickness of the icing on the surfaces of the two structural components increase(decrease)gradually.展开更多
The stray crystal in the platform region is one of the common main defects in single-crystal superalloy blades. The simple and effective method to eliminate this defect is urgent to be explored. This work found that t...The stray crystal in the platform region is one of the common main defects in single-crystal superalloy blades. The simple and effective method to eliminate this defect is urgent to be explored. This work found that the Cusp magnetic field can effectively inhibit the stray-crystal formation in the platform. The tendency of stray-crystal formation decreases as the magnetic-field strength increases at a certain withdrawal rate and temperature-gradient. The suppressing effect decreases as the withdrawal rate or the temperature-gradient increases. Finally, the inhibiting mechanism on the stray-crystal formation from the Cusp magnetic field is proposed based on the experiments and the numerical simulation. The magneticfield application strengthens the flow velocity and changes the flow structure near the liquid-solid interface, and further reduces the radial temperature difference. Accordingly, the secondary dendrites in the heat-conduction undercooled zone expands towards the corner in a faster speed, which reduces the stray-crystal formation in the platform corner. This study provides an effective and simple method for decreasing the stray-crystal formation during the preparation of single-crystal with platform region.展开更多
基金the National Natural Science Foundation of China(Grant No.51879125)Jiangsu Provincial Higher Education Natural Science Research Major Project(Grant No.18KJA580003)Jiangsu Province“Six Talents Peak”High-level Talents Support Project(Grant No.2018-KTHY-033).
文摘The Polar Regions are rich in natural resources but experience an extremely cold climate.The surfaces of offshore platforms operating in the Polar Regions are prone to icing.To develop solutions to this problem of surface icing,the influence of both the liquid water concentration of the surrounding atmosphere and the average water droplet diameter on the formation of ice on two major structural components of offshore platforms was analyzed using a combination of Fluent and FENSAP-ICE.Results showed that at a wind speed of 7 m/s,as the concentration of liquid water in the air increases from 0.05 to 0.25 g/m3,the amount and thickness of the icing on the surfaces of the two structural components increase linearly.At a wind speed of 7 m/s and when the size of the average water droplet diameter is 20–30(30–35)μm,as the average water droplet diameter increases,the amount and thickness of the icing on the surfaces of the two structural components increase(decrease)gradually.
基金financially supported by the National Natural Science Foundation of China (No.51871142)the Independent Research and Development Project of State Key Laboratory of Advanced Special Steel,Shanghai Key Laboratory of Advanced Ferrometallurgy,Shanghai University (No.SKLASS 2020-Z04)the Science and Technology Commission of Shanghai Municipality (No.19DZ2270200)。
文摘The stray crystal in the platform region is one of the common main defects in single-crystal superalloy blades. The simple and effective method to eliminate this defect is urgent to be explored. This work found that the Cusp magnetic field can effectively inhibit the stray-crystal formation in the platform. The tendency of stray-crystal formation decreases as the magnetic-field strength increases at a certain withdrawal rate and temperature-gradient. The suppressing effect decreases as the withdrawal rate or the temperature-gradient increases. Finally, the inhibiting mechanism on the stray-crystal formation from the Cusp magnetic field is proposed based on the experiments and the numerical simulation. The magneticfield application strengthens the flow velocity and changes the flow structure near the liquid-solid interface, and further reduces the radial temperature difference. Accordingly, the secondary dendrites in the heat-conduction undercooled zone expands towards the corner in a faster speed, which reduces the stray-crystal formation in the platform corner. This study provides an effective and simple method for decreasing the stray-crystal formation during the preparation of single-crystal with platform region.
