Numerical Simulation Of Forming For Continuous Helical Baffles

The heat transfer performance of heat exchanger with continuous helical baffle is all right, and its heat transfer efficiency is higher than the heat exchanger with traditional segment baffle or non-continuous helical baffle. This kind of heat exchanger has small fluid resistance. But the continuous helical baffle plate is difficult to fabricate. At present, the die stamping is one of most widely used techniques for continuous helical baffle forming. But in conventional stamping, the mold is difficult to make. The die’s universality is poor, and different shape parts require different dies. So the economy of the traditional forming method is poor. The production period is long. Therefore, the continuous helical baffle needs a more perfect manufacturing method.A method of multi-point forming(MPF) for the continuous helical baffle was proposed in this paper. Multi-point forming is a flexible processing method, and its target shape can be adjusted. The application of this method has been found in the manufacturing of curved hull plate, streamlined train front panels, and so on. And a lot of successful experience had been achieved. Therefore, according to the shape characteristics of continuous helical baffle, the method of multi-point forming for the continuous helical baffles was proposed in this text.Extensive numerical simulations of forming helical baffle plates were carried out by using a commercial software ANSYS/LS-DYNA. The stress, strain and springback in the forming process of helical baffle plate were investigated through the simulation. The simulation results show that the thickness strain of the helical baffle decreases along the radial direction from inside to outside. The springback decreases gradually with the increasing of the thickness.The influence factors such as thickness of plate, materials, the pitch of helical baffle, the helical baffle’s inside diameter and the size of punches were studied in this paper. The numerical simulation results of helical baffle plates demonstrate that defects of helical baffle forming are related to these factors. The defects of indentation and wrinkling decrease with an increase in thickness of helical baffle plate; the phenomenon of dimple and wrinkling increases with the increasing of the pitch; the dimple defects reduce with the increasing of the inner diameter. Under the same conditions, the defect of dimple decreases with the increasing of external diameter. And with the decreasing of basic bodies’ size, the phenomenon of dimple and wrinkle reduce. The research on multi-point forming of continuous helical baffle plate shows that the defects of indentation and wrinkling can be completely inhibited in the allowable range. They have no harmful influence on the use of continuous helical baffle. Therefore, the method of multi-point forming for continuous helical baffle is completely feasible.