The total storage of full containment LNG storage tanks is very huge. Once the tank rupture or leakage, the consequence will be unimaginable. Therefore it is necessary to perform the risk-based inspection （RBI） and ...The total storage of full containment LNG storage tanks is very huge. Once the tank rupture or leakage, the consequence will be unimaginable. Therefore it is necessary to perform the risk-based inspection （RBI） and evaluation on LNG storage tanks, and the analysis on LNG storage tanks failure possibility is especially important in the RBI. Recently, Risk-based inspection （RBI） technology based on API 581 is gradually adopted and has become a new technology to determine economic feasibility and safety of equipment in petrochemical plants. However, there are limitations of applying API 581 to LNG equipment because of the unique structure of LNG storage tank （the metal inner tank and concrete outer tank）. Therefore, a failure probability calculation model suitable for full containment LNG storage tanks is proposed. The domestic inner tank is usually made of 9%Ni, and its failure possibility can be calculate based on API581; the outer tank is usually made of pre-stressed concrete, and the failure possibility of structure durability can be calculated by the method of fuzzy mathematics ; Then the failure possibility of the inner tank and the outer tank will be comprehensive considered by using cellulose model. Finally, by citing a real example, it also detailedly introduces the application of this proposed calculation model in the failure possibility analysis of full containment LNG storage tanks. This study provides a new approach for the evaluation of failure possibility on full containment LNG storage tanks.展开更多
The vibration characteristics of offshore cylindrical tanks are studied in this paper. This is a typical topic of liquid-shell interaction system. In this paper, a general analytical method is presented by which the a...The vibration characteristics of offshore cylindrical tanks are studied in this paper. This is a typical topic of liquid-shell interaction system. In this paper, a general analytical method is presented by which the axial modal functions of liquid and shell are represented as the same complete orthogonal series for uncoupling the mode of liquid and shell. Simultaneously, the mode functions are expanded into a uniform convergence series and a linear polynomial, so that the problem of convergence and differentiation of mode series is solved. Therefore, the rather exact natural frequency and its corresponding mode of offshore cylindrical tank with different liquid depths, with arbitrary boundary conditions and with intermediate constraints can be obtained.展开更多
The estimation of sloshing loading on liquid tanks is of fundamental importance due to the wide and important applications of liquid tanks in various engineering aspects. Analytical solutions for the sloshing loading ...The estimation of sloshing loading on liquid tanks is of fundamental importance due to the wide and important applications of liquid tanks in various engineering aspects. Analytical solutions for the sloshing loading on circular cylindrical liquid tanks with an interior concentric vertical thin semi-porous barrier under external excitations are presented. And the extensions of the solutions to the elastic vibrations and to the high frequency limit to count for the earthquake response are also included. A clear view on the influence of semi-porous barriers to the sloshing response of oscillating tanks is obtained by the analyses of systematic computational results. The present results may offer guidance to the corresponding design for liquid tanks of various applications and also a basis of comparison for the development of more sophisticated numerical methods for hydrodynamic and hydro-elastic analyses.展开更多
This paper presents a method for solving Lagrangian version of governing equations that allows boundary conditions at the free surface to be satisfied exactly, which is a three-dimensional generalization of a method f...This paper presents a method for solving Lagrangian version of governing equations that allows boundary conditions at the free surface to be satisfied exactly, which is a three-dimensional generalization of a method first put forward by Stoker. Analytical expressions of nonlinear hydrodynamic pressure up to the third order and of free surface displacement up to the fourth order of an accelerating cylindrical tank were obtained. Here only the motions of objects in their early stage after initial impulses was considered. As a justification of the method, the important special case when the ratio of tank diameter to fluid depth tends to infinity was taken as an example, which shows that the linear hydrodynamic pressure obtained agrees completely with Westergaard or von Karman's classical result.展开更多
Cavitation tests of hydraulic model were carried out in vacuum tank. A classical theory for cavitation tests in vacuum tank has been used. According to two principles, the test procedure in vacuum tank and the predict...Cavitation tests of hydraulic model were carried out in vacuum tank. A classical theory for cavitation tests in vacuum tank has been used. According to two principles, the test procedure in vacuum tank and the prediction of cavitation features on prototype were obtained. However, by using these test results it can not make a reliable prediction of cavitation feature on prototype. It shows what should be the considerable reasons for the difficulties in comparison between the results of cavitation tests in vacuum tank and how to improve the cavitation tests under a condition of vacuum pressure.展开更多
The characteristics of the catchment discharge vary with land use. The characteristics of the long-term discharge of a terraced paddy field catchment were studied. Two kind of tank models for land use were proposed an...The characteristics of the catchment discharge vary with land use. The characteristics of the long-term discharge of a terraced paddy field catchment were studied. Two kind of tank models for land use were proposed and used to simulate the discharge of the catchment: one is a forest type model used as the upper part of the catchment; the other is a paddy field type model used as the lower part of the catchment. The results of the model simulation were analyzed and compared with that of a forest catchment.展开更多
文摘The total storage of full containment LNG storage tanks is very huge. Once the tank rupture or leakage, the consequence will be unimaginable. Therefore it is necessary to perform the risk-based inspection （RBI） and evaluation on LNG storage tanks, and the analysis on LNG storage tanks failure possibility is especially important in the RBI. Recently, Risk-based inspection （RBI） technology based on API 581 is gradually adopted and has become a new technology to determine economic feasibility and safety of equipment in petrochemical plants. However, there are limitations of applying API 581 to LNG equipment because of the unique structure of LNG storage tank （the metal inner tank and concrete outer tank）. Therefore, a failure probability calculation model suitable for full containment LNG storage tanks is proposed. The domestic inner tank is usually made of 9%Ni, and its failure possibility can be calculate based on API581; the outer tank is usually made of pre-stressed concrete, and the failure possibility of structure durability can be calculated by the method of fuzzy mathematics ; Then the failure possibility of the inner tank and the outer tank will be comprehensive considered by using cellulose model. Finally, by citing a real example, it also detailedly introduces the application of this proposed calculation model in the failure possibility analysis of full containment LNG storage tanks. This study provides a new approach for the evaluation of failure possibility on full containment LNG storage tanks.
基金Project supported by the National Natural Science Foundation of China
文摘The vibration characteristics of offshore cylindrical tanks are studied in this paper. This is a typical topic of liquid-shell interaction system. In this paper, a general analytical method is presented by which the axial modal functions of liquid and shell are represented as the same complete orthogonal series for uncoupling the mode of liquid and shell. Simultaneously, the mode functions are expanded into a uniform convergence series and a linear polynomial, so that the problem of convergence and differentiation of mode series is solved. Therefore, the rather exact natural frequency and its corresponding mode of offshore cylindrical tank with different liquid depths, with arbitrary boundary conditions and with intermediate constraints can be obtained.
文摘The estimation of sloshing loading on liquid tanks is of fundamental importance due to the wide and important applications of liquid tanks in various engineering aspects. Analytical solutions for the sloshing loading on circular cylindrical liquid tanks with an interior concentric vertical thin semi-porous barrier under external excitations are presented. And the extensions of the solutions to the elastic vibrations and to the high frequency limit to count for the earthquake response are also included. A clear view on the influence of semi-porous barriers to the sloshing response of oscillating tanks is obtained by the analyses of systematic computational results. The present results may offer guidance to the corresponding design for liquid tanks of various applications and also a basis of comparison for the development of more sophisticated numerical methods for hydrodynamic and hydro-elastic analyses.
文摘This paper presents a method for solving Lagrangian version of governing equations that allows boundary conditions at the free surface to be satisfied exactly, which is a three-dimensional generalization of a method first put forward by Stoker. Analytical expressions of nonlinear hydrodynamic pressure up to the third order and of free surface displacement up to the fourth order of an accelerating cylindrical tank were obtained. Here only the motions of objects in their early stage after initial impulses was considered. As a justification of the method, the important special case when the ratio of tank diameter to fluid depth tends to infinity was taken as an example, which shows that the linear hydrodynamic pressure obtained agrees completely with Westergaard or von Karman's classical result.
文摘Cavitation tests of hydraulic model were carried out in vacuum tank. A classical theory for cavitation tests in vacuum tank has been used. According to two principles, the test procedure in vacuum tank and the prediction of cavitation features on prototype were obtained. However, by using these test results it can not make a reliable prediction of cavitation feature on prototype. It shows what should be the considerable reasons for the difficulties in comparison between the results of cavitation tests in vacuum tank and how to improve the cavitation tests under a condition of vacuum pressure.
文摘The characteristics of the catchment discharge vary with land use. The characteristics of the long-term discharge of a terraced paddy field catchment were studied. Two kind of tank models for land use were proposed and used to simulate the discharge of the catchment: one is a forest type model used as the upper part of the catchment; the other is a paddy field type model used as the lower part of the catchment. The results of the model simulation were analyzed and compared with that of a forest catchment.
