Effect of trench geometry, cable size and top layer thickness on the heat dissipation in buried cables

Abstract

The geometrical dimensions of the trench and the type of top layer used for the installation of buried cable are considered. These dimensions include the trench width and depth, cable depth and diameter, and thickness of the top layer. The dimensions, such as the trench width and the cable diameter, are varied to emphasize their effect on the heat dissipation. A simple model using the finite difference technique is used to determine the temperature at each node of the grid, and the Gauss-Siedel iteration method is used to solve the temperature equations. The heat dissipation from buried cables can be increased either by using larger cable diameter or by increasing the width of the trench. The number of grid points has a remarkable influence on the predicted value of heat dissipation. The percentage of the change in the heat dissipation due to the diameter or the trench width remains approximately the same for various grid points. The heat balance analysis shows that the difference between the cable heat dissipation and the heat losses from the grid boundaries is less than 0.3%, and the convective surface at the grid top plays a major role in dissipating the heat produced by the cable by almost 86% for most of the trenches with various widths. >