Influence of a modulated electromagnetic field on fouling in a double-pipe heat exchanger

In this study, the effect of a modulated electromagnetic field (MEF) on fouling in a double-pipe heat exchanger (DPHE) has been investigated. A double-loop-configuration consisting of cooling and heating water cycles was used for the experiments. The quality of heat transfer in the DPHE was studied via in situ monitoring of the fouling resistance. Moreover, the influence of cooling water linear velocity, on the MEF treatment efficiency has also been investigated. In this regard, the water flow velocities of 0.5, 0.8 and 1.3 ms−1 were selected. Results show that the application of the MEF on the cooling water flowing at 0.5 ms−1 velocity, decreased the fouling resistance in the heat exchanger by 76.3% compared to the blank (untreated) test. However, increasing the water velocity resulted in a decrease in the MEF efficiency, where 64.3% and 57.8% drop in fouling resistance of the DPHE was recorded for 0.8 and 1.3 ms−1 water velocities, respectively. On the other hand, the water ionic calcium (Ca2+) measurements showed a significant decrease in the cooling water calcium as a result of the MEF treatment. Finally, the MEF design parameters along with the responsible mechanism for the observed results have been discussed.