NUMERICAL-ANALYSIS OF ELECTRIC-FIELD IN A CLOSED SPACE INJECTED WITH CHARGED FLUID

The electric field in a closed space, where existing fluid is replaced by inflow of charged fluid, is sometimes of great importance in safety. The past method of calculation might bring a large error in the safety evaluation, since the method assumes the homogeneous distribution of electric charge and does not take into consideration its heterogeneity due to the charge transport by convection in the closed space. In order to get the precise electric field in consideration of this effect, it is necessary to comprehend the flow field in the space. In this study, the steam cleaning of cargo-holds of a tanker is used as an example. The flow field in a rectangular space is numerically calculated using several flow models. Then, the unsteady electric field, taking into consideration the mobility of charge, is obtained numerically and compared with experimental data obtained by the authors. As a result, it became clear that the mobility of charge is an important factor in determining the electric field in the closed space, and the accuracy of the safety evaluation for the avoidance of electrostatic accidents could be improved by considering the effect.