DEVELOPMENT OF VELOCIMETRY

测速技术的发展

• 批准号: 10211201
• 负责人: IGUCHI Manabu
• 金额: $ 29.5万
• 依托单位: HOKKAIDO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research on Priority Areas (B)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10211201/
• 关键词: VELOCIMETRY; MOLTEN METAL; MOLTEN STEEL; CONTINUOUS CASTING; LORENTZ FORCE; WAVE MOTION; SWIRL CURRENT; LEVEL SENSOR; 電磁力; ホール素子; 連続鋳造

There are two methods of electro-magnetically measuring the velocity of molten metal flow based on the fluctuation components. One processes the fluctuation components originally exist in the molten metal flow. The detail of the measurement method should be referred to a previous paper by Julius et al. The other processes the fluctuation components artificially imposed on the flow. This method is considered here. The measurement principle can be explained as follows :Wave motions are imposed on the surface of molten metal flowing in a vessel by using an alternating magnetic field. A transmitting coil is used to generate the magnetic field. The frequency of the wave motions is predetermined. The waves propagates both in the upstream and downstream directions. The wave motions can be detected by two receiving coils (level sensors) placed at upstream and downstream positions. The distance from the transmitting coil to the upstream sensor is the same as that from the transmitting coil to t … More he downstream sensor. There appears a time delay between the output signals of the two sensors. The time delay depends on the velocity of molten metal flow. Accordingly, the velocity of the molten metal flow can be determined from the time delay and the coil distance provided that the propagation speed of the wave motions is given. Fortunately, the propagation speed can be readily detected by some methods. It was 70cm/s under the present experimental conditions.The effects of the transmitting frequency, the coil distance, the distance from the molten metal surface to the coil (coil height) on the accuracy of this method was examined using an Wood's metal bath. A swirl current type level sensor was used as a receiving coil. The measurement was accurately carried out for a transmitting frequency of 100kHz, current of 10A, a coil height of 2 mm, a coil distance of 100mm, and a wave frequency of 0.8 Hz. The maximum velocity was 60 cm/s. It should be noted that the molten metal velocity higher than 70 cm/s cannot be measured with this method because the wave propagation velocity is 70cm/s under the present experimental conditions. This result suggests that the measurement of the molten steel flow velocity in the continuous casting mold is possible by this method. Less

基于波动分量的电磁测量熔融金属流速度的方法有两种，一种是处理熔融金属流中本来存在的波动分量，具体测量方法可参考Julius等人之前的论文。 al.其他过程人为地施加在流动上的波动分量可以解释如下：通过使用交变磁场在容器中流动的熔融金属的表面上施加波动。一个发射线圈用于产生磁场，波运动的频率是预先确定的，波运动可以通过放置在上游和下游位置的两个接收线圈（液位传感器）来检测。发射线圈到上游传感器的距离与发射线圈到下游传感器的距离相同。两个传感器的输出信号之间存在时间延迟。时间延迟取决于传感器的速度。因此，只要给出波运动的传播速度，就可以根据时间延迟和线圈距离来确定熔融金属流的速度。幸运的是，可以通过一些方法容易地检测到传播速度。在本实验条件下，速度为70cm/s。使用伍德金属浴考察了发射频率、线圈距离、熔融金属表面到线圈的距离（线圈高度）对该方法精度的影响。使用涡流式液位传感器作为接收线圈，在发射频率100kHz、电流10A、线圈高度2mm、线圈距离100mm、波频率0.8Hz下进行准确测量。最大速度为 60 cm/s 需要注意的是，由于波传播速度为 70 cm/s，因此无法用此方法测量高于 70 cm/s 的熔融金属速度。该结果表明，在现有的实验条件下，该方法可以测量连铸结晶器中的钢水流速。