Analysis of motion and heat transfer enhancement of staggered inverted flexible bodies in flow channels

For the purpose of heat transfer enhancement in the flow channel of heat exchangers, a rectangular flow heat transfer model with staggered inverted flexible disturbing bodies is established, and the effects of flexible disturbing bodies with different bending strengths and arrangement spacing on the flow and heat transfer in the flow channel are simulated by arbitrary Lagrangian-Euler (ALE) method. The results show that the flexible body with different bending strengths presents three motion modes under the same flow condition: bias, large amplitude flapping and deflection flapping. Compared with the flow channel without disturbing bodies, the three flapping modes of flexible disturbing bodies can increase the average Nu in the flow channel by 40.4%-70.6%, 45.1%-83.5% and 38.3%-75.1%, respectively. Increasing the vertical spacing of the staggered flexible bodies can also increase the average Nu in the flow channel. When the dimensionless vertical spacing is 0.7 and the flexible bodies are in large amplitude flapping mode, the average Nu in the flow channel reaches the maximum value, which is 85.8% higher than that in the non-disturbed flow channel, and the thermal efficiency coefficient is 6.5% higher than that in the non-disturbed flow channel.