DETERMINING THE THICKNESS OF THE BOILER SCALE IN THE PIPE OF A HEAT EXCHANGER BASED ON THE SOLUTION OF THE INVERSE PROBLEM

Abstract

The temperature inside the heat exchanger pipe in a steam boiler was subjected to analysis. Heating of the pipe with and without the scale was considered. A calculation model was presented describing the inverse problem of a geometrical type. It allows determining the thickness of the boiler scale based on the measurements of the temperature inside the pipe and the heat flow density on the outer wall of the heat exchanger pipe. The paper analyzes the sensitivity of the obtained temperature distributions in the pipe and in the scale. The temperature measurement error, the inaccuracy of the thermocouple fitting and the measurement error of the heat flow density on the pipe outer wall were taken into account. The thickness of the boiler scale was determined depending on its properties and thermal load of the exchanger element. The calculations were performed for the scales of the heat conductance λ from 0.3 to 1 W/mK. The proposed calculation model corresponds to a non-linear problem, in which the change of the heat conductance coefficient was taken into account depending on the temperature.

Keywords:
boiler scale, inverse problem, steam boilers