This paper describes the set up and application of a non hydrostatic Canadian meteorological numerical model (MC2) for mesoscale simulations of wind field and other meteorological parameters over the complex terrain...This paper describes the set up and application of a non hydrostatic Canadian meteorological numerical model (MC2) for mesoscale simulations of wind field and other meteorological parameters over the complex terrain of Hong Kong. Results of the simulations of one case are presented and compared with the results of radiosonde and aircraft measurements. The model is proved capable of predicting high resolution, three dimensional fields of wind and other meteorological parameters within the Hong Kong territory, using reasonable computer time and memory resources.展开更多
The highly loaded turbine blades are able to reduce both the number of blades and the stages of turbojet-engines. In this study, PIV(Particle Image Velocimetry) method is used for the measurements of the secondary flo...The highly loaded turbine blades are able to reduce both the number of blades and the stages of turbojet-engines. In this study, PIV(Particle Image Velocimetry) method is used for the measurements of the secondary flow in ultra-highly loaded turbine blade cascades. The results obtained by the PIV method clearly show the complicated behavior of the secondary flow in the cascade. The horseshoe vortex and the passage vortex are observed inside the cascade. Moreover, the wake generated by the accumulation of the low energy fluid by the passage vortex near the suction side and that discharged toward downstream of the trailing edge has been recognized.展开更多
The approach of utilizing combustion synthesis to make fine particles of SiO2, A12O3 and TiO2 is a quite modern technology. Through the chemical reaction in post-flame region, fine SiO2 particles can be formed with hi...The approach of utilizing combustion synthesis to make fine particles of SiO2, A12O3 and TiO2 is a quite modern technology. Through the chemical reaction in post-flame region, fine SiO2 particles can be formed with high purity on plate surface. Therefore, the combustion synthesis of SiO2 powders is an important area for further research and development especially for the application of SiO2 in the semiconductor industry. This investigation proposes an experimental approach （i.e., a gas-phase combustion synthesis） using two different kinds of organic compounds, Hexamethyldisilazane （HMDSA） and Hexamethyldisioxane （HMDSO）, as the silicon precursors. A premixed gas burner is chosen with C3H8 as fuel air as oxidant and part of the air was used as the carrying gas to entrain HMDSA/HMDSO vapor into the combustible mixture. Observations show that the C3H8/air flame changed color from a pale-blue flame to light yellow and then orange when different amounts of precursors were introduced. Through the chemical reaction in the post-flame region, fine SiO2 particles were formed in the gas phase and then quenched and collectal on an aluminum flat plate. The objective of this paper is to study the effects of HMDSO and HMDSA concentrations and flame temperatures on the synthesis of SiO2 particles.展开更多
文摘This paper describes the set up and application of a non hydrostatic Canadian meteorological numerical model (MC2) for mesoscale simulations of wind field and other meteorological parameters over the complex terrain of Hong Kong. Results of the simulations of one case are presented and compared with the results of radiosonde and aircraft measurements. The model is proved capable of predicting high resolution, three dimensional fields of wind and other meteorological parameters within the Hong Kong territory, using reasonable computer time and memory resources.
文摘The highly loaded turbine blades are able to reduce both the number of blades and the stages of turbojet-engines. In this study, PIV(Particle Image Velocimetry) method is used for the measurements of the secondary flow in ultra-highly loaded turbine blade cascades. The results obtained by the PIV method clearly show the complicated behavior of the secondary flow in the cascade. The horseshoe vortex and the passage vortex are observed inside the cascade. Moreover, the wake generated by the accumulation of the low energy fluid by the passage vortex near the suction side and that discharged toward downstream of the trailing edge has been recognized.
文摘The approach of utilizing combustion synthesis to make fine particles of SiO2, A12O3 and TiO2 is a quite modern technology. Through the chemical reaction in post-flame region, fine SiO2 particles can be formed with high purity on plate surface. Therefore, the combustion synthesis of SiO2 powders is an important area for further research and development especially for the application of SiO2 in the semiconductor industry. This investigation proposes an experimental approach （i.e., a gas-phase combustion synthesis） using two different kinds of organic compounds, Hexamethyldisilazane （HMDSA） and Hexamethyldisioxane （HMDSO）, as the silicon precursors. A premixed gas burner is chosen with C3H8 as fuel air as oxidant and part of the air was used as the carrying gas to entrain HMDSA/HMDSO vapor into the combustible mixture. Observations show that the C3H8/air flame changed color from a pale-blue flame to light yellow and then orange when different amounts of precursors were introduced. Through the chemical reaction in the post-flame region, fine SiO2 particles were formed in the gas phase and then quenched and collectal on an aluminum flat plate. The objective of this paper is to study the effects of HMDSO and HMDSA concentrations and flame temperatures on the synthesis of SiO2 particles.
