Experimental Study on Flow and Heat Transfer in a Circular Tube With Straight Frame Rotor Inserts

The flow and heat transfer characteristics in a circular tube with straight frame rotor inserts in various structure were experimentally researched.The results show that the straight frame rotor inserts enhance heat transfer and reduce fouling by increasing the velocity gradient and the disturbance near the tube wall due to their hollow structure,while the flow resistance increase is not too large.A lower helical angle,relatively smaller cross-sectional area of the straight sweeper rod and a convex shape are helpful for improving the overall heat transfer performance of a circular tube with straight frame rotor inserts.And the three-normal-three-reverse rotor insert arrangement leads to a better overall heat transfer performance.