The Effect of Cooling Rate on the Formation of Dendritic Ice in a Pipe With No Main Flow

Abstract

Dendritic ice forms in a pipe when there is no main flow through the pipe during the freezing process. This ice form occurs because the quiescent water supercools considerably below 0°C before ice nucleation occurs. It has been shown that growth of dendritic ice can cause blockage of a water pipe [1] much sooner than would have been predicted if the ice grew as a solid annulus. The extent of the dendritic growth is largely determined by the temperature distribution that exists in the pipe at the time of ice nucleation. In this paper the factors effecting the temperature distribution and thus the extent of dendritic ice growth are examined to determine the conditions under which blockage by dendritic ice is likely to occur. The factors that are important are the cooling rate the pipe is exposed to, the ice nucleation temperature, and the type of thermal boundary condition the pipe wall provides.