Although many literatures have been focused on the underneath flow and loss mechanism, very few experiments and simulations have been done under the engines' representative working conditions or considering the re...Although many literatures have been focused on the underneath flow and loss mechanism, very few experiments and simulations have been done under the engines' representative working conditions or considering the real cavity structure as a whole. This paper aims at realizing the goal of design of efficient turbine and scrutinizing the velocity distribution in the vicinity of the rim seal. With the aid of numerical method, a numerical model describing the flow pattern both in the purge flow spot and within the mainstream flow path is established, fluid migration and its accompanied flow mechanism within the realistic cavity structure(with rim seal structure and considering mainstream & secondary air flow's interaction) is used to evaluate both the flow pattern and the underneath flow mechanism within the inward rotating cavity. Meanwhile, the underneath flow and loss mechanism are also studied in the current paper. The computational results show that the sealing air flow's ingestion and ejection are highly interwound with each other in both upstream and downstream flow of the rim seal. Both the downstream blades' potential effects as well as the upstream blades' wake trajectory can bring about the ingestion of the hot gas flow within the cavity, abrupt increase of the static pressure is believed to be the main reason. Also, the results indicate that sealing air flow ejected through the rear cavity will cause unexpected loss near the outlet section of the blades in the downstream of the HP rotor passages.展开更多
浮顶罐易发生火灾的部位为二次密封圈,通常在设计阶段为其配置固定泡沫灭火系统和消防冷却水系统,然而在储罐泡沫灭火系统泡沫喷射验收中,发现泡沫混合液通过泡沫产生器发泡后,沿罐壁流至泡沫堰板环形区域内,泡沫通过堰板进入罐顶,未覆...浮顶罐易发生火灾的部位为二次密封圈,通常在设计阶段为其配置固定泡沫灭火系统和消防冷却水系统,然而在储罐泡沫灭火系统泡沫喷射验收中,发现泡沫混合液通过泡沫产生器发泡后,沿罐壁流至泡沫堰板环形区域内,泡沫通过堰板进入罐顶,未覆盖至二次密封的高度,无法扑灭密封圈火灾。通过泡沫喷射试验,找到导致灭火失败的直接原因是泡沫堰板高度不足,通过测量5×10~4m^3储罐的泡沫堰板和二次密封圈的高度,计算泡沫覆盖二次密封圈的时间和消耗泡沫液量,将泡沫堰板高度增加至0.9 m,并增加泡沫储备量,确保泡沫连续喷射时间大于1 h 19 min,并提出了相应的风险控制对策。展开更多
基金the National Natural Science Foundation of China for sponsoring the research described in the current paper(No.51406204)
文摘Although many literatures have been focused on the underneath flow and loss mechanism, very few experiments and simulations have been done under the engines' representative working conditions or considering the real cavity structure as a whole. This paper aims at realizing the goal of design of efficient turbine and scrutinizing the velocity distribution in the vicinity of the rim seal. With the aid of numerical method, a numerical model describing the flow pattern both in the purge flow spot and within the mainstream flow path is established, fluid migration and its accompanied flow mechanism within the realistic cavity structure(with rim seal structure and considering mainstream & secondary air flow's interaction) is used to evaluate both the flow pattern and the underneath flow mechanism within the inward rotating cavity. Meanwhile, the underneath flow and loss mechanism are also studied in the current paper. The computational results show that the sealing air flow's ingestion and ejection are highly interwound with each other in both upstream and downstream flow of the rim seal. Both the downstream blades' potential effects as well as the upstream blades' wake trajectory can bring about the ingestion of the hot gas flow within the cavity, abrupt increase of the static pressure is believed to be the main reason. Also, the results indicate that sealing air flow ejected through the rear cavity will cause unexpected loss near the outlet section of the blades in the downstream of the HP rotor passages.
文摘浮顶罐易发生火灾的部位为二次密封圈,通常在设计阶段为其配置固定泡沫灭火系统和消防冷却水系统,然而在储罐泡沫灭火系统泡沫喷射验收中,发现泡沫混合液通过泡沫产生器发泡后,沿罐壁流至泡沫堰板环形区域内,泡沫通过堰板进入罐顶,未覆盖至二次密封的高度,无法扑灭密封圈火灾。通过泡沫喷射试验,找到导致灭火失败的直接原因是泡沫堰板高度不足,通过测量5×10~4m^3储罐的泡沫堰板和二次密封圈的高度,计算泡沫覆盖二次密封圈的时间和消耗泡沫液量,将泡沫堰板高度增加至0.9 m,并增加泡沫储备量,确保泡沫连续喷射时间大于1 h 19 min,并提出了相应的风险控制对策。
