Optimization research on the spiral-insert structure based on symmetric spiral fluidization in horizontal tubes

摘要

To resolve the fouling problems in heat exchangers, this paper studied the symmetric spiral fluidization cleaning technology through experiments. The spiral-insert structure is optimized under the condition of the minimum flow rate needed in the spiral fluidization in horizontal heat transfer tubes. The steel spiral of different pitches are inserted in a 050 x 3 mm horizontal tube respectively. The fluidized particle size is 4.8 mm-6.5 mm and the volume concentration is in the range of 2.5% to 5%. The experiment results show that the minimum flow rate required by the symmetric spiral fluidization is inversely proportional to the spiral pitch. This means the larger the spiral pitch is, the lower the minimum flow rate in need to remove the fouling from the tube inside the wall for the same particle size and concentration. The minimum flow speed is as low as 0.36 m/s and the flow resisitance is low, 1.5 KPa/m, when the optimal spiral is used, whose wire diameter is 2 mm, spiral diameter is 40 mm and spiral pitch is 51 mm.