Strength Studies Of The Tube-To-Tbuesheet Hydraulically Expanded Joints

Shell-and-tube heat exchangers are widely used in petrochemicalindustries.The connection joints between tubes and tube-sheets turn to bethe weakest parts in an exchanger construction, which often lead to theleakage of the joints and finally the uselessness of the exchanger.Owing tomany advantages, hydraulic expansion technique is increasingly employedfor the connection of tubes and tube-sheets of shell-and-tube heatexchangers.Because parameters of the expanded pressure and theexpanded construction in the hydraulically expanded joint haven't thecorresponding criterion, it is necessary to resolve the question of selectingthese parameters by experiments and theories, providing the reference ofthe corresponding criterion and standard. In this thesis we have preceded the material function experiments.Experiments and Finite Element Analysis (ANSYS) were performed on thestrength of the tube-to-tubesheet hydraulically expanded joints and theeffects of expansion pressures, grooving of tube holes, groove width andlocations were investigated.It is found the pull-out forces of the jointsincrease with increasing the expansion pressures in the range of normalpressure.Grooving on the tube hole will enhance the joint strengthsignificantly, which is owing to the serious scratch between the tube andthe brink of the groove.For a grooved joint, the larger the groove width*this research subsidized by Beijing Natural Science Fund(serial number3002009) - 3 -北京化工大学硕士学位论文and the closer the distance of the groove to the tubesheet middle surface,the greater the pull-out forces.