Similarity of lubrication in armature-rail interface under the condition of electromagnetic railgun's physical field scaling method

Lubrication performance in armature-rail interface is an important issue in electromagnetic railgun, while the scaling method of existing electromagnetic railgun field can not involve the lubrication. In order to further improve the effectiveness of the tests on sub-scale electromagnetic railgun, governing equations were obtained according to the lubrication mechanism in armature-rail interface, and the scaling method was derived based on the governing equations using similarity theory. The lubrication performance was presented under the condition of railgun field scaling method, and numerical simulations were then undertaken to assess the scaling performance. The results show that matching the Reynolds number(Re) is the key point in lubrication scaling. Lubrication scaling under the condition of velocity matching railgun field scaling method can be achieved by setting the identical initial interface gaps between the sub scale and the full scale. Setting the smaller geometric scaling factor in armature length direction than the whole launcher is favorable for the performance of the lubrication scaling. © 2016, High Voltage Engineering Editorial Department of CEPRI. All right reserved.