Salt Damage and Electrical Leak on Porous Walls: A Simulation Study

Abstract

Salt damage to materials is a challenge faced by both industry and the common man causing great economic losses. Two aspects of  salt  damage  are  addressed in this work- (i) salt crystallization on exposed porous wall (ii) salt damage induced electrical leakage in the damp porous wall. We address salt damage to porous wall where damage is caused by the deposition of saline droplets of water on the surface, as in salt spray, using a 3-dimensional modelling of the entire phenomena – construction of a porous system - deposition and drying of salt-spray - salt crystallization and finally electrical leakage. The two problems are studied as a function of different drying rates . Our studies indicate that electrical leakage due to salt damp on walls shows a damped oscillatory behaviour. The frequency of oscillation is higher for higher drying rates. The authors explain the oscillation in the electrical output as a competition between two time scales - (a) diffusive transport of salt ions (b) increase in salt concentration in exposed pores at channel surface that is determined by the drying rate.