Analytical solution and experimental verification for pulsed laser heating process with convective boundary condition  

作　　者：HE Yunfeng DU Dong SUN Zhenguo CHEN Qiang PAN Jiluan 

机构地区：[1]Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China

出　　处：《Science China(Technological Sciences)》2004年第3期305-319,共15页中国科学（技术科学英文版）

基　　金：the National Natural Science Foundation of China (Grant No. 50275083) ; the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions of MOE, China.

摘　　要：Laser heating process of materials is a complex heat transfer problem involved with laser beam, workpiece and ambience. In particular, variable convective boundary condition has great influence on temperature field distribution and processing quality. However, in the previous studies of temperature field抯 solution, convective boundary condition was either simplified or ignored which affected calculation accuracy and precision. In this paper, an analytical solution for the temperature field with convective boundary condition is obtained using Laplace transforms. Moreover, the dimensionless parameters are identified appropriately. Influence of dimensionless distance (x′), dimensionless time (t ), dimensionless energy absorption at surface (M) and Biot number (Bi) on dimensionless temperature (T′) have been investigated. The results show: as Bi is increased, the effects of the heat convection become more pronounced and make the location of the peak temperature move away from the surface. The method of thermocamera is used to validate the analytical solution for pulsed laser heating process with convective boundary condition and the ideal results are obtained. The present study provides the theoretical basis for improving the understanding of physical process, exact modelling and quality controlling of laser welding and surface treatment.Laser heating process of materials is a complex heat transfer problem involved with laser beam, workpiece and ambience. In particular, variable convective boundary condition has great influence on temperature field distribution and processing quality. However, in the previous studies of temperature field抯 solution, convective boundary condition was either simplified or ignored which affected calculation accuracy and precision. In this paper, an analytical solution for the temperature field with convective boundary condition is obtained using Laplace transforms. Moreover, the dimensionless parameters are identified appropriately. Influence of dimensionless distance (x′), dimensionless time (t ), dimensionless energy absorption at surface (M) and Biot number (Bi) on dimensionless temperature (T′) have been investigated. The results show: as Bi is increased, the effects of the heat convection become more pronounced and make the location of the peak temperature move away from the surface. The method of thermocamera is used to validate the analytical solution for pulsed laser heating process with convective boundary condition and the ideal results are obtained. The present study provides the theoretical basis for improving the understanding of physical process, exact modelling and quality controlling of laser welding and surface treatment.

关 键 词：laser HEATING process  heat convection  temperature field  ANALYTICAL solution  thermography. 

分 类 号：TH[机械工程]