Evaluation of general applicability of microwave NDT to pipes with a bend focusing on mode conversion
概要
This study evaluates the key factors impacting on multi-mode conversion of microwave when applying microwave NDT to bent pipe inspection. Mathematical derivation demonstrates the dependence of multi- mode conversion due to a bend on three factors: the ratio of bending radius to pipe’s diameter, the bend angle and the frequency normalized with the cut-off frequency of an arbitrary mode. To verify the deducting results, numerical simulations were conducted to evaluate multi-mode conversion of bent pipe adopting TE01 microwave mode as excitation. Simulation results showed that in spite of different inner diameters, transmission characteristics of microwaves propagating in bent pipes manifest excellent consistency if the pipes are characterized by the same three aforementioned factors.
