关键词: 边界识别, 导热反问题, 有限元法, 共轭梯度法, 红外检测

Abstract: A two-dimensional physical and mathematical transient heat transfer model for the pipeline with irregular inner geometry boundary is built.The identification problem of pipeline inner boundary is solved by using finite element method and conjugate gradient method(CGM)-based inverse algorithm.The differences of sensitivities of the transient and steady pipeline outer surface temperature to the inner boundary change are analyzed and certified by a series of numerical simulation experiments,in which the influences of temperature measurement errors and initial inner boundary guesses are tested.It is found that the temperature measurement errors and initial inner boundary guesses have no obvious effect on the pipeline inner boundary identification results when the infrared inspection is carried out in the transient heat transfer state,while the accuracy of the boundary identification results is poor with temperature measurement errors when the infrared inspection is carried out in the steady heat transfer state.Therefore,in the engineering application,in order to identify the inner geometry boundary accurately,the infrared inspection in the transient heat transfer state is more appropriate than that in steady heat transfer state.

Key words: boundary identification, inverse heat conduction problem, finite element method, conjugate gradient method, infrared inspection