System modelling and device development for passive acoustic monitoring of a particulate-liquid process

System modelling and device development for passive acoustic monitoring of a particulate-liquid process

This paper presents the development of a passive ultrasonic monitoring system for the detection of acoustic emission (AE) created by chemical particles striking the inner wall of a reactor vessel. The finite element (FE) code PZFlex was used to analyze the complex interactions between chemical particles and the vessel wall. A 4-layer 2D model was developed comprising a liquid load medium and a glass-oil-glass combination corresponding to the jacketed vessel reactor. The model has been experimentally validated with excellent correlation achieved. The excitation function was derived from Hertz's theory and used as the model stimulus corresponding to particles striking the inner glass wall. Analysis of the FE simulations provided the transducer specifications for a passive ultrasonic monitoring system. The system comprises two transducers with complementary characteristics: narrow bandwidth/high sensitivity; wideband/low sensitivity. Importantly, the sensitivity of the resonant transducer provides discrimination of particle concentration. Moreover, the broader bandwidth of the off-resonant device demonstrates potential for estimation of particle size. The performance afforded by this approach has considerable potential for real-time process monitoring in the chemicals and pharmaceutical industries.

本文介绍了一种被动超声监测系统的研发，该系统用于检测化学颗粒撞击反应容器内壁所产生的声发射（AE）。使用有限元（FE）代码PZFlex分析化学颗粒与容器壁之间的复杂相互作用。开发了一个4层二维模型，包括液体负载介质以及与夹套式反应容器相对应的玻璃 - 油 - 玻璃组合。该模型已通过实验验证，取得了极好的相关性。激励函数源自赫兹理论，并用作与颗粒撞击玻璃内壁相对应的模型激励。对有限元模拟的分析为被动超声监测系统提供了换能器规格。该系统包含两个具有互补特性的换能器：窄带宽/高灵敏度；宽带/低灵敏度。重要的是，谐振换能器的灵敏度可区分颗粒浓度。此外，非谐振装置更宽的带宽显示出估计颗粒大小的潜力。这种方法所提供的性能在化工和制药行业的实时过程监测方面具有相当大的潜力。