Author(s): Ivar Horjen; Torkild Carstens
Linked Author(s): Torkild Carstens
Keywords: No Keywords
Abstract: A model of trash rack anti-icing using heating cables is presented. The model is applied for a realistic case appropriate for a power plant in cold regions. Supplied heat power and heating cable temperature as a function of external flow speed, bar width normal to flow direction and frazil number concentration are presented. Two "modes" of anti-icing heat input are considered: A) no melting of colliding frazil and B) complete melting of colliding frazil. In both cases the temperature of the trash rack surface is kept at zero degree. The heat power is at least one order larger for case B than for case A. For both cases the heat power increases more or less linearly with increasing water flow speed in front of the trash rack. Further, the heat power is almost independent of bar width for case A, wIlle the main tendency is an increase of heat power with increasing width for case B. The frazil number concentration has a considerable effect upon the necessary anti-icing heat power: for case A there is an exponential decrease with increasing concentration while for case B the opposite is true when concentrations are above 2x10^5 m^-3. The paper does also contain a discussion of the choice of convective heat transfer coefficient to be used in the model.
Year: 1994