According to the ship observation data over the South Indian Ocean during 1950 1995, taking 1°× 1° and 5°× 5°grid, the characteristics and variation rule of wind are analyzed. Through ana...According to the ship observation data over the South Indian Ocean during 1950 1995, taking 1°× 1° and 5°× 5°grid, the characteristics and variation rule of wind are analyzed. Through analyzing the chart of isopleths of the monthly elements, the conclusion that the seasonal variation of the wind field over the South Indian Ocean is less remarkable than that in the oceans of the Northern Hemisphere is got. The seasonal variation of the wind field is also obvious in this region, but the seasonal difference is little. The wind in winter is stronger than in summer, correspondingly, the average wind speed is higher, and the frequencies of gale of forces ≥ 6 and 8 are also higher. The north of 10°S is a monsoon area; Southeast wind prevails all over the year in the rest of the trade wind area; Westerly wind dominates in the south of 40°S. This paper provides specific data of wind field and variation for ship ocean transportation, ocean-going visits and scientific experiment.展开更多
Tropical disturbances over the South China Sea (SCS) during the period of 1997-2006 are analyzed using the Tropical Storm and Hurricane WX products. A total of 158 tropical disturbances were formed over the SCS from 1...Tropical disturbances over the South China Sea (SCS) during the period of 1997-2006 are analyzed using the Tropical Storm and Hurricane WX products. A total of 158 tropical disturbances were formed over the SCS from 1997 to 2006, with 54 de-veloping tropical disturbances which developed into tropical depressions and 104 non-developing tropical disturbances which never developed into tropical depressions. The development rate of tropical disturbances into tropical depressions was 34.18% in these ten years. During the period of this study, total annual numbers of tropical disturbances and developing tropical disturbances over the SCS had significant decreasing trends; however, the development rate of tropical disturbances had an insignificant increasing trend.展开更多
As the performance of an air-cooled condenser is apt to be affected by the fluctuating ambient condition, some difficulties are brought to the use of a steam feeding water pump in an air-cooled unit. This paper introd...As the performance of an air-cooled condenser is apt to be affected by the fluctuating ambient condition, some difficulties are brought to the use of a steam feeding water pump in an air-cooled unit. This paper introduces a new design of for steam feeding the water pump of an air-cooled unit using the back-pressure steam turbine as the prime motor. Using variable condition analysis on a 600 MW direct air-cooled unit, and with consideration of the effect on the ambient conditions, the feasibility, economy, and adaptability of the design are verified.展开更多
The static voltage stability of the power system integrating wind farms adopting different kinds of wind turbines is analyzed. Through the simulation of one certain local power grid in Xinjiang Uygur Autonomous Region...The static voltage stability of the power system integrating wind farms adopting different kinds of wind turbines is analyzed. Through the simulation of one certain local power grid in Xinjiang Uygur Autonomous Region, the PV curves at the point of common coupling (PCC), key buses and important substations are plotted; the variation of voltage as well as the limit and margin of static stability are analyzed. It is resulted from the simulation that the limit of static voltage at weak nodes is lower, and the static voltage of the power system with wind farms adopting doubly-fed induction generators (DFIG) is more stable than that with wind farms adopting common asynchronous generators.展开更多
The original internal flooding probabilistic safety analysis （PSA） study of Krsko Nuclear Power Plant （two-loop Pressurized Water Reactor （PWR） plant of Westinghouse design） was performed in mid nineties and lim...The original internal flooding probabilistic safety analysis （PSA） study of Krsko Nuclear Power Plant （two-loop Pressurized Water Reactor （PWR） plant of Westinghouse design） was performed in mid nineties and limited to reactor core damage risk （Level 1 PSA）. In 2003, it was, together with other safety and hazard analyses, subject to the Periodic Safety Review （PSR）. In the PSR, it was stated that methodological PSA approaches and guidelines have evoluted during the past decade and several observations were provided, concerning the area screening process, residual risk and treatment of plant damage states and risk from radioactivity releases （i.e., Level 2 PSA）. In order to address the PSR observations, upgrade ofKrsko NPP internal flooding PSA was undertaken. The area screening process was revisited in order to cover the areas without automatic reactor trip equipment. The model was extended to Level 2. Residual risk was estimated at both Level 1 and Level 2, in terms of core damage frequency （CDF） and large early release frequency （LERF）, respectively.展开更多
The applied technology of high roller-compacted concrete(RCC) dams is quite complicated because of various risk factors, including the weather condition, supply of concrete aggregate, efficiency of transport machinery...The applied technology of high roller-compacted concrete(RCC) dams is quite complicated because of various risk factors, including the weather condition, supply of concrete aggregate, efficiency of transport machinery and dam surface machinery, and so on. In order to ensure the comprehensiveness, accuracy and objectivity of construction schedule risk analysis, a mathematical model called improved correlated schedule risk analysis model(CSRAM) is proposed in this paper. This model takes into account not only the construction features of high RCC dams, but also the stochastic variations of risk factors with the construction schedule, as well as their comprehensive effects. Using Monte Carlo method to solve this model enables the completion probability of a high RCC dam construction within plan time, and uncertainty analysis of risk factors. Compared with the conventional CSRAM, the improved CSRAM has higher completion probability and more convergent distribution of a simulation period, making analysis results more accurate and closer to actual engineering conditions. Among the ten risk factors selected, efficiency of dam surface machinery and proficiency of workers are found to be of the maximum uncertainty.展开更多
The hypersonic long-run scramjet test tunnel is one of the key ground facilities for the studies of ramjet/scramjet and hypersonic thermal management.Due to the significantly large heat loading,the nozzle of the tunne...The hypersonic long-run scramjet test tunnel is one of the key ground facilities for the studies of ramjet/scramjet and hypersonic thermal management.Due to the significantly large heat loading,the nozzle of the tunnel facility demands effective cooling protection.In this work,the two-dimensional,three-dimensional and axisymmetric Mach 6.5 nozzles at an inlet total temperature of 1840 K and a total pressure of 6.4 MPa were studied with main focuses on the properties of aerodynamic heating of nozzles.The present work aims to provide insights into the design of an effective cooling system for the nozzle and other components of the hypersonic long-run wind tunnel.展开更多
文摘According to the ship observation data over the South Indian Ocean during 1950 1995, taking 1°× 1° and 5°× 5°grid, the characteristics and variation rule of wind are analyzed. Through analyzing the chart of isopleths of the monthly elements, the conclusion that the seasonal variation of the wind field over the South Indian Ocean is less remarkable than that in the oceans of the Northern Hemisphere is got. The seasonal variation of the wind field is also obvious in this region, but the seasonal difference is little. The wind in winter is stronger than in summer, correspondingly, the average wind speed is higher, and the frequencies of gale of forces ≥ 6 and 8 are also higher. The north of 10°S is a monsoon area; Southeast wind prevails all over the year in the rest of the trade wind area; Westerly wind dominates in the south of 40°S. This paper provides specific data of wind field and variation for ship ocean transportation, ocean-going visits and scientific experiment.
基金supported by Chinese Academy of Sciences(Grant KZCX2-YW-214)NSFC Grants 40875020 and 41075054+2 种基金the Fundamental Research Funds for the Central Universities(Nos.11lgpy13 and 11lgjc10)sponsored by the tropical marine meteorology fund from the Institute of Tropical and Marine Meteorology,CMA,SOED1108Scientific Research Foundation for the Young Teachers Program of Sun Yat-sen University(No. 38000-3181402)
文摘Tropical disturbances over the South China Sea (SCS) during the period of 1997-2006 are analyzed using the Tropical Storm and Hurricane WX products. A total of 158 tropical disturbances were formed over the SCS from 1997 to 2006, with 54 de-veloping tropical disturbances which developed into tropical depressions and 104 non-developing tropical disturbances which never developed into tropical depressions. The development rate of tropical disturbances into tropical depressions was 34.18% in these ten years. During the period of this study, total annual numbers of tropical disturbances and developing tropical disturbances over the SCS had significant decreasing trends; however, the development rate of tropical disturbances had an insignificant increasing trend.
文摘As the performance of an air-cooled condenser is apt to be affected by the fluctuating ambient condition, some difficulties are brought to the use of a steam feeding water pump in an air-cooled unit. This paper introduces a new design of for steam feeding the water pump of an air-cooled unit using the back-pressure steam turbine as the prime motor. Using variable condition analysis on a 600 MW direct air-cooled unit, and with consideration of the effect on the ambient conditions, the feasibility, economy, and adaptability of the design are verified.
基金National Natural Science Foundation of China(5076700350867004)Autonomous university research projects(XJEDU2007105)
文摘The static voltage stability of the power system integrating wind farms adopting different kinds of wind turbines is analyzed. Through the simulation of one certain local power grid in Xinjiang Uygur Autonomous Region, the PV curves at the point of common coupling (PCC), key buses and important substations are plotted; the variation of voltage as well as the limit and margin of static stability are analyzed. It is resulted from the simulation that the limit of static voltage at weak nodes is lower, and the static voltage of the power system with wind farms adopting doubly-fed induction generators (DFIG) is more stable than that with wind farms adopting common asynchronous generators.
文摘The original internal flooding probabilistic safety analysis （PSA） study of Krsko Nuclear Power Plant （two-loop Pressurized Water Reactor （PWR） plant of Westinghouse design） was performed in mid nineties and limited to reactor core damage risk （Level 1 PSA）. In 2003, it was, together with other safety and hazard analyses, subject to the Periodic Safety Review （PSR）. In the PSR, it was stated that methodological PSA approaches and guidelines have evoluted during the past decade and several observations were provided, concerning the area screening process, residual risk and treatment of plant damage states and risk from radioactivity releases （i.e., Level 2 PSA）. In order to address the PSR observations, upgrade ofKrsko NPP internal flooding PSA was undertaken. The area screening process was revisited in order to cover the areas without automatic reactor trip equipment. The model was extended to Level 2. Residual risk was estimated at both Level 1 and Level 2, in terms of core damage frequency （CDF） and large early release frequency （LERF）, respectively.
基金supported by the Innovative Research Groups of the National Natural Science Foundation of China(Grant No.51321065)the National Basic Research Program of China("973"Project)(Grant No.2013CB035906)the National Natural Science Foundation of China(Grant No.51339003)
文摘The applied technology of high roller-compacted concrete(RCC) dams is quite complicated because of various risk factors, including the weather condition, supply of concrete aggregate, efficiency of transport machinery and dam surface machinery, and so on. In order to ensure the comprehensiveness, accuracy and objectivity of construction schedule risk analysis, a mathematical model called improved correlated schedule risk analysis model(CSRAM) is proposed in this paper. This model takes into account not only the construction features of high RCC dams, but also the stochastic variations of risk factors with the construction schedule, as well as their comprehensive effects. Using Monte Carlo method to solve this model enables the completion probability of a high RCC dam construction within plan time, and uncertainty analysis of risk factors. Compared with the conventional CSRAM, the improved CSRAM has higher completion probability and more convergent distribution of a simulation period, making analysis results more accurate and closer to actual engineering conditions. Among the ten risk factors selected, efficiency of dam surface machinery and proficiency of workers are found to be of the maximum uncertainty.
基金supported by the National Natural Science Foundation of China(Grant Nos.11202218 and 11172309)
文摘The hypersonic long-run scramjet test tunnel is one of the key ground facilities for the studies of ramjet/scramjet and hypersonic thermal management.Due to the significantly large heat loading,the nozzle of the tunnel facility demands effective cooling protection.In this work,the two-dimensional,three-dimensional and axisymmetric Mach 6.5 nozzles at an inlet total temperature of 1840 K and a total pressure of 6.4 MPa were studied with main focuses on the properties of aerodynamic heating of nozzles.The present work aims to provide insights into the design of an effective cooling system for the nozzle and other components of the hypersonic long-run wind tunnel.
