Electromagnetic Generation of Compression Waves in a Liquid Metal

压缩波在液态金属过程中具有细化凝固组织、脱气、促进反应速率等诱人的作用。然而，由于电致伸缩或磁致伸缩振子的功率限制、功率变送器与液态金属接触时的溶解等原因，它们还没有在工业上得到应用。另一方面，利用电磁场也可以在液态金属中激发压缩波。这种方法可以解决上述问题。也就是说，我们可以在非接触操作下激发出大功率压缩波。本研究提出了压缩波的电磁激励方法，并通过实验验证了该方法激发的压缩波在凝固过程中的工业实用作用。本文提出的励磁方法之一是在液态金属…上同时施加静磁场和交变磁场此外，还有一种是同时施加静磁场和交变电流。在这两种情况下，都从理论和实验上证实了压缩波的激发。此外，在凝固过程中用后一种方法激发的压缩波可以获得细化的宏观组织。由于在地球上很难激发Alfven波，因此Alfen波主要在天体物理领域进行研究。然而，在超导技术的发展下，我们可以在液态金属中激发它们。因此，Alfven Waves有可能成为一种过程控制工具。本文对液态金属中Alfven波的激发方法进行了理论和实验研究。从理论上推导了液态金属中Alfven波的压力分布，并与金属中的实测压力进行了比较。结果表明，两种方法具有较好的一致性。然后，新提出的方法对激发Alfven波是有用的。此外，在Alfven波的作用下，得到了细化的宏观组织。较少

Compression waves have attractive functions in liquid metal processes such as refinement of solidified structure, degassing, promotion of reaction rate and so on. However, they have not been used in industry because of the power limitation of electrostrictive or magnetostrictive vibrators, dissolution of power transmitter contacting with a liquid metal. On the other hand, compression waves can also be excited in a liquid metal by using an electromagnetic field. This method can solve problems mentioned above. That is, we can excite large power compression waves under non-contacting operation. In this research, electromagnetic excitation methods of compression waves have been proposed and industrially useful function of compression waves excited by the proposed method in solidification processing has been demonstrated in the experiment. One of the excitation method proposed here is the simultaneous imposition of a static magnetic field and an alternating magnetic field on a liquid metal … More and the other one is the simultaneous imposition of a static magnetic field and an alternating electric current. In both cases, excitation of compression waves was theoretically and experimentally confirmed. Furthermore, refined macrostructure of the Sn-Pb alloy was obtained under the imposition of compression waves excited by the latter method during solidification.Alfven waves have been mainly studied in the field of astrophysics since it was very difficult to excite on the earth. However, under the development of super conducting technology, we can excite them in a liquid metal. Therefore, Alfven waves have a possibility as a process control tool. Here, excitation method of Alfven waves in a liquid metal has been investigated theoretically and experimentally. Pressure distribution accompanying Alfven waves in a liquid metal was theoretically derived and it was compared with the measured pressure in the metal. The both results shows a good agreement. Then, the newly proposed method is useful to excite Alfven waves. Furthermore, refined macrostructure of the Sn-Pb alloy was obtained under the imposition of Alfven waves during its solidification. Less