PULSATIVE HEATING OF SURFACES

Laser repetitive pulse heating is one of the research fields in laser heating of engineering surfaces. The effect of assisting gas jet on th e laser heating process is usually omitted in the previous studies. Th e present study examines the gas jet assisted laser repetitive pulse h eating of steel surfaces. The flow and temperature fields are predicte d numerically using the control volume approach. The two-dimensional a xisymmetric heat conduction equation is solved for the solid substance , while continuity, momentum, energy and equation of state are conside red for the impinging air, which is introduced coaxially with the lase r beam and orthogonal to the workpiece surface as the assisting gas. T he low Reynolds number k-epsilon model is used to account for the turb ulence in the flow field. The solid and gas properties are considered as variable. The study is extended to include three pulse types and tw o gas jet velocities. It is found that the thermal integration for the repetitive pulses of high cooling periods is unlikely and the effect of gas jet velocity is not substantial on the resulting solid side tem perature profiles. (C) 1998 Published by Elsevier Science Ltd. AU righ ts reserved.