Full
Outline
To address the issue of uncertain pressure pulsation characteristics during the cyclic downward movement of particles in a standpipe-valve system and the lack of quantitative characterization，an experimental study on pressure pulsation characteristics was conducted.By varying the particle mass flow rate，the dynamic pressure of the gas-solid two‑phase flow before and after the valve （at measuring points P1 and P2） was measured.Through analytical methods including dynamic pressure，static pressure，standard deviation，and power spectral density，the pressure fluctuation characteristics within the standpipe-valve system were thoroughly investigated.The results indicate that as the particle mass flow rate Gs increases from 0 to 117.72 kg/（m²⋅s），significant low‑frequency，high‑amplitude pressure fluctuations occur in the system，primarily due to particle clustering，gas‑solid interactions，and bubble disturbances.The standard deviation of the dynamic pressure at point P2 shows a linear relationship with the particle mass flow rate，suggesting that the standard deviation can be used for real‑time monitoring of the particle mass flow rate in circulating fluidized beds.When the particle mass flow rate Gs=0，both points P1 and P2 on the standpipe exhibit a single dominant frequency with relatively low power spectral density.As the particle mass flow rate increases to 6.28 kg/（m²⋅s），both P1 and P2 display dual‑frequency characteristics，comprising a primary frequency and a secondary frequency.The power spectral density at P1 initially increases and then decreases with increasing particle mass flow rate，while at P2，it increases with increasing particle mass flow rate.The pressure pulsations within the standpipe are all low‑frequency （<0.41 Hz） and act as the excitation force causing standpipe vibration.This study provides a theoretical basis and experimental support for the optimal design and safe operation of particle circulation systems in circulating fluidized beds.
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| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |
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