Investigation of fouling mitigation using stationary and rotating twisted tapes

The fouling phenomenon is one of the critical issues to be solved in industrial heat exchangers, which can adversely affect the size of the heat exchanger, thermofluids performance, and operational lifetime. In this paper, a novel fouling mitigation technique using stationary and rotating twisted tapes is introduced. The particulate fouling phenomenon was experimentally studied using the accelerated fouling test. The aluminum oxide particle was used as a foulant material, and the experiments were performed for different twisted tape pitches (60 mm and 120 mm), flow rates (1.5–5 l min⁻¹), and particle sizes (1.2 µm and 6.9 µm). The results showed that within the turbulent flow region, the fouling resistance decreased with an increase in flow rate. Moreover, compared to the plain tubes, a maximum of 68% and 90% reduction in fouling resistance was attained using the rotating twisted tapes for the 1.2 µm and 6.9 µm particle sizes, respectively. Compared to the tube with stationary twisted tape, the rotating twisted tape provided an additional 16% reduction in the fouling resistance for the 1.2 µm particle size. However, for both plain and twisted tape tubes, the pressure drop of the fouled tube is about 2–24% higher than the unfouled tube.