(1. 江西理工大學(xué)機(jī)電工程學(xué)院，贛州 341000；
2. 江西理工大學(xué)材料科學(xué)與工程學(xué)院，贛州 341000)
摘 要: 為探明鋁合金熔體在電磁場作用下的流動特征，利用Fluent軟件模擬電磁場作用下鋁熔體中微粒的流動軌跡，計算這些流動軌跡的混沌特征參數(shù)：最大Lyapunov指數(shù)及Kolmogorov熵。并根據(jù)不同電磁頻率攪拌下鋁合金熔體中微粒的運動軌跡，對其進(jìn)行混沌特征判斷及分析。結(jié)果表明：鋁合金熔體在電磁場作用下的流動具有混沌特征；電磁頻率為5、15和30 Hz時，在鋁合金熔體中都發(fā)生了混沌對流，其最大Lyapunov指數(shù)都大于0，且其Kolmogorov熵隨著電磁頻率增大而迅速增加，說明其系統(tǒng)內(nèi)混沌程度越大，信息損失量也越大。
關(guān)鍵字: 鋁合金熔體；Lyapunov指數(shù)；Kolmogorov熵；混沌對流；電磁場
（1. School of Mechanical and Electronic Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, China;
2. School of Materials Science and Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, China）
Abstract:In order to find out the flow features of Al alloy melt under the electromagnetic field，the trajectories of the particle in Al alloy melt was simulated by the computational fluid dynamics software Fluent, and the chaotic characteristic parameters such as max Lyapunov exponent and Kolmogorov entropy were calculated, and they were used to characterize the trajectories of three groups. The chaotic characters on the flow trajectories of Al alloy melt were judged and analyzed according to the trajectories of the particle in the melt under the electromagnetic field. The results show that there is chaotic character for flow in Al alloy melt under electromagnetic field. Chaotic advection happens in the melt at different frequencies such as 5, 15 and 30 Hz. The maximum Lyapunov exponents are beyond 0. And Kolmogorov entropy increases rapidly with increasing the frequencies, indicating that its system has more degree of chaos and more information loss.
Key words: Al alloy melt; Lyapunov exponent; Kolmogorov entropy; chaotic advection; electromagnetic field
