基于激光测量技术的双多组浸没撞击流流场特性的非线性研究

The impinging stream technique had very important application prospects in chemical industry field. It displayed advantageous functions on aspects of intensifying alternate delivery, promoting microcosmic commixture and process dynamics,it was widely applied to precipitation,crystal, and fetching the ultra fine powder,and so on. Many documents had already carried out ralative expositions. Applicant considered that the unique flow structure and condition in impinging area was the important reason for these features mentioned abbove and applications.Two-multi jets impinged against each other with high velocity and formed strong turbulent area,which is the feature of impinging stream. A lot of valuable message are included in flow velocity,however, because its principle and process is very complicated, impinging stream is not researched in depth. The project intends to use double-multigroup submerged impinging stream reactor and adopt laser three-dimensional Doppler to measure the instantaneous velocity, time averaged velocity，concentration and turbulent kinetic energy distribution law of flow field in double-multigroup submerged impinging stream reactor，find out flow characteristics in impinging area. By means of the nonlinearity research method, calculates the multigroup nonlinearity parameters describing the chaotic flow field , and according to the main principles and methods of turbulent count theories, verifies the turbulent scale law in inertia area and compares the dissent in the energy distribution state between impinging stream and general turbulent flow. By the method of numerical simulation, finds the solutions of three-dimensional and non-constant differential equation. On the basis of hydromechanics equation, builds up a "double-multigroup submerged impinging stream" mathematic model by simplifying flow field parameters and suggesting necessary hypothesis,etc. The project reserches nonlinearity Dynamics characteristics of this equation , such as singular point,closedown, bifurcation, chaos etc,and compares with nonlinearity parameter acquiring from experiment data, amends model defects further, improves this theory model. On these bases, researches the feasibility about chaotic control and forecast of this model, finally, expands the model and applies to engineering.

撞击流技术在化工领域具有重要的应用前景，在强化相间传递、促进微观混合、制取超细粉体等方面具有优越的性能，申请人认为，撞击区流场独特的流动结构和状态，是产生这一现象的重要原因。本项目拟采用三维激光多普勒测速技术获取双多组浸没撞击流反应器流场的瞬时和时均速度、浓度、湍流动能分布规律；通过非线性研究方法，计算出描述混沌流场的多组非线性特征参数，并按照湍流统计理论的主要原则和方法，验证湍流惯性子区标度律，比较撞击流与一般湍流在能谱分布状态的异同；采用数值模拟的方法，模拟求解流场的三维非定常微分方程；依据基本流体力学方程，通过简化流场参量、提出必要假设等手段，建立"双多组浸没撞击流"的数学模型。研究该模型方程的奇点、闭轨、分岔、混沌等非线性动力学特征，并与从实验数据中获得的非线性参量对比，进一步修正模型缺陷，完善该理论模型，以此为基础研究该模型的混沌控制与预测的可行性，最终放大该模型以应用于工程。

撞击流技术以其有效促进微观混合，强化相间传热传质的优越性能在工业领域具有广阔的应用前景。本项目基于先进的激光测量技术，对双多组撞击流流场特性进行了非线性研究。利用PDA、PIV、PLIF技术对不同操作条件下撞击流反应（混合）器内的速度场、浓度场进行测量，获得撞击流混合（反应）器流场的宏观速度、浓度、能量分布规律，描述出各阶速度、浓度随撞击强度和操作条件的变化关系，揭示了撞击流反应器中的流体运动特征。利用混沌分析、分形分析、小波变换等非线性分析方法对测量数据进行处理，证明了流场的混沌特性，并计算出描述混沌流场的非线性参数，确认参数与流场宏观运动特征之间的关系及对混合效果的影响。采用数值模拟方法，对多种结构和撞击方式的速度场、浓度场进行研究，从而优化设计得到双组分层的新型反应器结构。以本项目成果为核心技术，建立了新型撞击流混合工业示范装置，利用其进行粉体制备，得到了满足工业要求的微米级颗粒，并实现了科技成果转化。