Hurst方法可用于揭示流型转变,区分部分不同类型颗粒的流动结构,检测流化床内气体分布的不均匀性。本文基于Hurst方法对脉动流化床床层稳定性进行分析。通过改变细颗粒含量、流化气速和脉动能量,对床层压力信号进行监测,来实现对脉动流...Hurst方法可用于揭示流型转变,区分部分不同类型颗粒的流动结构,检测流化床内气体分布的不均匀性。本文基于Hurst方法对脉动流化床床层稳定性进行分析。通过改变细颗粒含量、流化气速和脉动能量,对床层压力信号进行监测,来实现对脉动流化床床层稳定性进行研究。研究结果表明:适当添加细颗粒可提高床层稳定性;增加流化气速,在一定范围内,气泡小,流化均匀稳定,超过一定范围,干扰因素增加,床层波动剧烈;引入脉动能量,可以削弱气泡扰动、降低气泡频率,但超过一定范围削弱能力会减弱。The Hurst method can be used to reveal flow pattern transitions, distinguish the flow structures of different types of particles, and detect the non-uniformity of gas distribution in fluidized beds. This article analyzes the stability of a pulsating fluidized bed based on the Hurst method by changing the fine particle content, gas velocity, and pulsating energy, the bed pressure signal was monitored to study the stability of the pulsating fluidized bed. The research results indicate that adding fine particles appropriately can improve the stability of the bed;Increasing the fluidization gas velocity, within a certain range, the bubbles are small, and the fluidization is uniform and stable. Beyond a certain range, the interference factors increase, and the bed fluctuates violently;Introducing pulsating energy can weaken bubble disturbance and reduce bubble frequency, but beyond a certain range, the weakening ability will weaken.展开更多
The abrupt occurrence of the Zhongbao landslide is totally unexpected,resulting in the destruction of local infrastructure and river blockage.To review the deformation history of the Zhongbao landslide and prevent the...The abrupt occurrence of the Zhongbao landslide is totally unexpected,resulting in the destruction of local infrastructure and river blockage.To review the deformation history of the Zhongbao landslide and prevent the threat of secondary disasters,the small baseline subsets(SBAS)technology is applied to process 59 synthetic aperture radar(SAR)images captured from Sentinel-1A satellite.Firstly,the time series deformation of the Zhongbao landslide along the radar line of sight(LOS)direction is calculated by SBAS technology.Then,the projection transformation is conducted to determine the slope displacement.Furthermore,the Hurst exponent of the surface deformation along the two directions is calculated to quantify the hidden deformation development trend and identify the unstable deformation areas.Given the suddenness of the Zhongbao landslide failure,the multi-temporal interferometric synthetic aperture radar(InSAR)technology is the ideal tool to obtain the surface deformation history without any monitoring equipment.The obtained deformation process indicates that the Zhongbao landslide is generally stable with slow creep deformation before failure.Moreover,the Hurst exponent distribution on the landslide surface in different time stages reveals more deformation evolution information of the Zhongbao landslide,with partially unstable areas detected before the failure.Two potential unstable areas after the Zhongbao landslide disaster are revealed by the Hurst exponent distribution and verified by the GNSS monitoring results and deformation mechanism discussion.The method combining SBASInSAR and Hurst exponent proposed in this study could help prevent and control secondary landslide disasters.展开更多
文摘Hurst方法可用于揭示流型转变,区分部分不同类型颗粒的流动结构,检测流化床内气体分布的不均匀性。本文基于Hurst方法对脉动流化床床层稳定性进行分析。通过改变细颗粒含量、流化气速和脉动能量,对床层压力信号进行监测,来实现对脉动流化床床层稳定性进行研究。研究结果表明:适当添加细颗粒可提高床层稳定性;增加流化气速,在一定范围内,气泡小,流化均匀稳定,超过一定范围,干扰因素增加,床层波动剧烈;引入脉动能量,可以削弱气泡扰动、降低气泡频率,但超过一定范围削弱能力会减弱。The Hurst method can be used to reveal flow pattern transitions, distinguish the flow structures of different types of particles, and detect the non-uniformity of gas distribution in fluidized beds. This article analyzes the stability of a pulsating fluidized bed based on the Hurst method by changing the fine particle content, gas velocity, and pulsating energy, the bed pressure signal was monitored to study the stability of the pulsating fluidized bed. The research results indicate that adding fine particles appropriately can improve the stability of the bed;Increasing the fluidization gas velocity, within a certain range, the bubbles are small, and the fluidization is uniform and stable. Beyond a certain range, the interference factors increase, and the bed fluctuates violently;Introducing pulsating energy can weaken bubble disturbance and reduce bubble frequency, but beyond a certain range, the weakening ability will weaken.
基金support from the National Key R&D Program of China(Grant No.2021YFB3901403)Project supported by graduate research and innovation foundation of Chongqing,China(Grant No.CYS23115)Special project for performance incentive and guidance of scientific research institutions in Chongqing(Grant No.cstc2021jxjl120011)are greatly appreciated。
文摘The abrupt occurrence of the Zhongbao landslide is totally unexpected,resulting in the destruction of local infrastructure and river blockage.To review the deformation history of the Zhongbao landslide and prevent the threat of secondary disasters,the small baseline subsets(SBAS)technology is applied to process 59 synthetic aperture radar(SAR)images captured from Sentinel-1A satellite.Firstly,the time series deformation of the Zhongbao landslide along the radar line of sight(LOS)direction is calculated by SBAS technology.Then,the projection transformation is conducted to determine the slope displacement.Furthermore,the Hurst exponent of the surface deformation along the two directions is calculated to quantify the hidden deformation development trend and identify the unstable deformation areas.Given the suddenness of the Zhongbao landslide failure,the multi-temporal interferometric synthetic aperture radar(InSAR)technology is the ideal tool to obtain the surface deformation history without any monitoring equipment.The obtained deformation process indicates that the Zhongbao landslide is generally stable with slow creep deformation before failure.Moreover,the Hurst exponent distribution on the landslide surface in different time stages reveals more deformation evolution information of the Zhongbao landslide,with partially unstable areas detected before the failure.Two potential unstable areas after the Zhongbao landslide disaster are revealed by the Hurst exponent distribution and verified by the GNSS monitoring results and deformation mechanism discussion.The method combining SBASInSAR and Hurst exponent proposed in this study could help prevent and control secondary landslide disasters.
