境界要素法を用いた熱交換器のガルバニック腐食解析

抄録

A new effective three-dimensional boundary element method is developed for predicting the galvanic corrosion rate of heat exchanger. Since a heat exchanger consists of a huge number of slender tubes and a brass tube plate direct application of conventional numerical procedures needs so many elements that computation becomes impossible.
In the newly proposed method, the surface of the tube plate (which is connected to many tubes) is regarded as a surface of one virtual metal. At first, the polarization curve of the virtual metal is obtained by analyzing a tube unit which consists of one tube and a part of tube plate. Then the side water room is analyzed with a rather coarse mesh by employing the polarization curve of the virtual metal. Finally, the potential and current density thus calculated are used to determine the detailed distributions of potential and current density on the surfaces of an arbitrary tube and the tube plate.
A real heat exchanger is analyzed by the proposed method to demonstrate its practical applicability. This method may be applicable not only to a corrosion problem of a heat exchanger, but also to heat conduction problems of similar structures.