Biography

Biography: Peng-Sheng Wei

Abstract

This study theoretically identifies the factors affecting the keyhole collapse during drilling with a high power density laser or electron beam from fundamental principles of thermal physics. Laser drilling is widely used in various manufacturing technologies. This work studies quasi-steady one-dimensional compressible flow behavior of the two-phase vapor-liquid dispersion in a vertical keyhole of varying cross-section, paying particular attention to the transition between the annular and slug flows. The results show increases in absorbed energy, beam radius, entrained energy and specific heat ratio reduce capability of drilling. The drilling keyhole in which a subsonic gas mixture flows usually gives rise to keyhole collapse. The predicted results agree with physical intuition and exact closed-form solutions derived in the absence of friction and energy absorption. Controlling the factors to enhance efficiency and quality of drilling is therefore provided in this work and informed that would help this recognition.