A model was built to simulate liquid aluminum leakage during the casting process,including transient trough flow,orifice outflow,and spread,to prevent the explosion.A comparison between the simulation data and the the...A model was built to simulate liquid aluminum leakage during the casting process,including transient trough flow,orifice outflow,and spread,to prevent the explosion.A comparison between the simulation data and the theoretical calculation results verifies that the model has remarkable adaptability and high accuracy.Although the height of liquid aluminum in the mixing furnace and outlet radius are changed,the molten aluminum will not leak during the casting process.The aluminum in the trough moves forward in a wave-like motion and causes a leakage.The spread of the leaked aluminum resembles a long strip on the ground.The leakage amount and spread area of liquid aluminum increase with increasing the height of liquid aluminum in the mixing furnace.展开更多
CuCr alloys are prepared by mechanical alloying and explosive compaction. After we have studied their structure and flaws, the results show that the CuCr alloys have definite strength and toughness, while their fractu...CuCr alloys are prepared by mechanical alloying and explosive compaction. After we have studied their structure and flaws, the results show that the CuCr alloys have definite strength and toughness, while their fractured surface displays ductile characteristics. In the metallurgical structure, CuCr alloys are composed of two phases of uniform distribution; the SEM morphology is like thin strips with an end arrangement that is bonded to each other and the two-phase distribution of CuCr alloys is more homogenous. It is in only in a very small zone that formation of Cu-rich and Cr-rich phases take place. The flaws of the compaction samples are mainly central-holes and cracks.展开更多
In order to analyze the influence of vapor cloud shape on temperature field effect of unconfined vapor cloud explosion(UVCE)and obtain creditable prediction method of explosion temperature effect,the transient tempera...In order to analyze the influence of vapor cloud shape on temperature field effect of unconfined vapor cloud explosion(UVCE)and obtain creditable prediction method of explosion temperature effect,the transient temperature fields of cylindrical and hemispherical UVCEs with same methane concentration and mass were numerically studied by computational fluid dynamics(CFD)technology.According to numerical simulation results, the concepts of UVCE’s temperature-near-field and temperature-far-field were proposed,the corresponding ranges were given,and the temperature attenuation laws and differences in corresponding regions with different vapor cloud shapes were presented.Through comparing with Baker fireball model,the accuracy and visualizability in acquisition of entire temperature effect based on numerical simulation were further validated.The functional relations among maximum temperature,horizontal distance,initial temperature and vapor cloud mass in temperature-near-field and temperature-far-field were deduced by means of data fitting,respectively.These conclusions provided quantitative basis for forecast and protection of UVCE disaster.展开更多
基金The authors are grateful for the financial supports from the National Key R&D Program of China(2017YFC0805100).
文摘A model was built to simulate liquid aluminum leakage during the casting process,including transient trough flow,orifice outflow,and spread,to prevent the explosion.A comparison between the simulation data and the theoretical calculation results verifies that the model has remarkable adaptability and high accuracy.Although the height of liquid aluminum in the mixing furnace and outlet radius are changed,the molten aluminum will not leak during the casting process.The aluminum in the trough moves forward in a wave-like motion and causes a leakage.The spread of the leaked aluminum resembles a long strip on the ground.The leakage amount and spread area of liquid aluminum increase with increasing the height of liquid aluminum in the mixing furnace.
文摘CuCr alloys are prepared by mechanical alloying and explosive compaction. After we have studied their structure and flaws, the results show that the CuCr alloys have definite strength and toughness, while their fractured surface displays ductile characteristics. In the metallurgical structure, CuCr alloys are composed of two phases of uniform distribution; the SEM morphology is like thin strips with an end arrangement that is bonded to each other and the two-phase distribution of CuCr alloys is more homogenous. It is in only in a very small zone that formation of Cu-rich and Cr-rich phases take place. The flaws of the compaction samples are mainly central-holes and cracks.
基金Supported by the National Natural Science Foundation of China（10772029） the Ph.D Programs Foundation of Ministry of Education of China（20050007029） the Independent Research Subject of State Key Laboratory of Explosion Science and Technology（ZDKT08-02）
文摘In order to analyze the influence of vapor cloud shape on temperature field effect of unconfined vapor cloud explosion(UVCE)and obtain creditable prediction method of explosion temperature effect,the transient temperature fields of cylindrical and hemispherical UVCEs with same methane concentration and mass were numerically studied by computational fluid dynamics(CFD)technology.According to numerical simulation results, the concepts of UVCE’s temperature-near-field and temperature-far-field were proposed,the corresponding ranges were given,and the temperature attenuation laws and differences in corresponding regions with different vapor cloud shapes were presented.Through comparing with Baker fireball model,the accuracy and visualizability in acquisition of entire temperature effect based on numerical simulation were further validated.The functional relations among maximum temperature,horizontal distance,initial temperature and vapor cloud mass in temperature-near-field and temperature-far-field were deduced by means of data fitting,respectively.These conclusions provided quantitative basis for forecast and protection of UVCE disaster.
