As the Arctic Channel continues to be developed,collisions between polar navigation vessels and sea ice are inevitable,which will directly affect structural safety and vibration comfort.However,the numerical analysis ...As the Arctic Channel continues to be developed,collisions between polar navigation vessels and sea ice are inevitable,which will directly affect structural safety and vibration comfort.However,the numerical analysis method of ship-ice collision-induced vibration is not perfect,and the effect of fluid coupling is not typically considered.In this paper,a simplified numerical analysis method for ship-ice collision-induced vibration is proposed,in which a reliable ice load is obtained by first performing ship-ice-water-air coupled collision calculations,followed by ship-ice-water coupled vibration calculations to obtain the vibration response of the structure.In addition,this paper investigates the full coupling method and the modeling ranges and meshing sizes involved in the analysis ship-ice collision-induced vibration,and the computational efficiencies of the traditional ALE algorithm and S-ALE algorithm are compared.The results indicate that the simplified simulation analysis method and gradient meshing model improve the calculation accuracy and efficiency in ship-ice collision and vibration response analysis.Moreover,the modeling range of the water and air models cannot be less than 6 times the ship width,2 times the ship length,and 1 times the ship depth,and the S-ALE algorithm saves 47.86%time compared to the ALE algorithm.The research results in this paper can provide a reference for the numerical simulation of ship-ice collision-induced vibration.展开更多
In this paper, a novel system using direct contact heat transfer between air and water solution was proposed to generate ice slurry. The heat transfer process and the system performance were studied; energy efficiency...In this paper, a novel system using direct contact heat transfer between air and water solution was proposed to generate ice slurry. The heat transfer process and the system performance were studied; energy efficiency coefficients of 0.038, 0.053, and 0.064 were obtained using different solutions. An empirical relationship between the volumetric heat transfer coefficient U v and the main parameters was obtained by fitting the experimental data. The U v calculated from the empirical formula agreed with the experimental U v quite well with a relative error of less than 15%. Based on the empirical formula, a laboratory-scale direct contact ice slurry generator was then constructed, with practical application in mind. If the air flow rate is fixed at 200 m 3 /h, the ice production rate will be 0.091 kg/min. The experimental results also showed that the cold energy consumption of the air compressor accounted for more than half of the total amount. To improve the system energy efficiency coefficient, it is necessary to increase the air pipes insulation and the solution's thermal capacity, and also it is appropriate to utilize the free cold energy of liquefied natural gas (LNG).展开更多
文摘As the Arctic Channel continues to be developed,collisions between polar navigation vessels and sea ice are inevitable,which will directly affect structural safety and vibration comfort.However,the numerical analysis method of ship-ice collision-induced vibration is not perfect,and the effect of fluid coupling is not typically considered.In this paper,a simplified numerical analysis method for ship-ice collision-induced vibration is proposed,in which a reliable ice load is obtained by first performing ship-ice-water-air coupled collision calculations,followed by ship-ice-water coupled vibration calculations to obtain the vibration response of the structure.In addition,this paper investigates the full coupling method and the modeling ranges and meshing sizes involved in the analysis ship-ice collision-induced vibration,and the computational efficiencies of the traditional ALE algorithm and S-ALE algorithm are compared.The results indicate that the simplified simulation analysis method and gradient meshing model improve the calculation accuracy and efficiency in ship-ice collision and vibration response analysis.Moreover,the modeling range of the water and air models cannot be less than 6 times the ship width,2 times the ship length,and 1 times the ship depth,and the S-ALE algorithm saves 47.86%time compared to the ALE algorithm.The research results in this paper can provide a reference for the numerical simulation of ship-ice collision-induced vibration.
基金Project (No. 51176164) supported by the National Natural Science Foundation of China
文摘In this paper, a novel system using direct contact heat transfer between air and water solution was proposed to generate ice slurry. The heat transfer process and the system performance were studied; energy efficiency coefficients of 0.038, 0.053, and 0.064 were obtained using different solutions. An empirical relationship between the volumetric heat transfer coefficient U v and the main parameters was obtained by fitting the experimental data. The U v calculated from the empirical formula agreed with the experimental U v quite well with a relative error of less than 15%. Based on the empirical formula, a laboratory-scale direct contact ice slurry generator was then constructed, with practical application in mind. If the air flow rate is fixed at 200 m 3 /h, the ice production rate will be 0.091 kg/min. The experimental results also showed that the cold energy consumption of the air compressor accounted for more than half of the total amount. To improve the system energy efficiency coefficient, it is necessary to increase the air pipes insulation and the solution's thermal capacity, and also it is appropriate to utilize the free cold energy of liquefied natural gas (LNG).
