Reliability Research On Wear Life Of Heat Transfer Tube Of Heat Exchanger

As a key interface in the primary and secondary circuits of the steam generator,the heat transfer tube is subject to stress concentration,vibration,corrosion and other challenges.Among the many failure modes of the heat transfer tube,the wear between the heat transfer tube and the anti-vibration strip occupies a larger proportion.It is difficult to replace the worn heat transfer tube,and the only way to block the tube.The wear of the heat transfer tube is affected by factors such as load and temperature,and these factors have many uncertainties.Therefore,conducting reliability research on the wear life of heat transfer tubes has important theoretical value and engineering guidance significance for the integrity of nuclear power equipment.In this paper,using the self-designed test device,the vibration characteristic test of the heat transfer tube is carried out.The spring is used to simulate the friction constraint between the heat transfer tube and the anti-vibration strip.A simplified load boundary based on the relationship between the clamping force and the spring stiffness K function is established.The wear calculation method proposed a reliability analysis method to predict the wear life of the heat transfer tube,pointed out the key factors affecting the life of the heat transfer tube,and through the improvement of the built device,the impact wear test of the heat transfer tube was carried out.The research contents and conclusions are as follows:?1?The effect of anti-vibration strip on the vibration characteristics of the heat transfer tube is discussed through experiments.The greater the clamping force,the stronger the restriction on the heat transfer tube,the greater the rigidity,and the greater the natural frequency of the heat transfer tube.When there is a gap between the heat transfer tube and the anti-vibration strip,as the gap increases,the frequency of vibration will gradually decrease.The number of anti-vibration strips also affects the frequency of heat transfer tube vibration.When the number of anti-vibration strips on the heat transfer tube is increased to 3 times,the frequency of the heat transfer tube will be increased to 4 times under the same clamping force.The natural frequency of the heat transfer tube when the clamping force is 20 N is 27.1 Hz,which is in accordance with the theoretical calculation value of 25.53 Hz.?2?A spring is used to simulate the friction constraint between the heat transfer tube and the anti-vibration bar,and a simplified wear calculation method based on the load boundary between the clamping force and the spring stiffness K function is established.The anti-vibration bar clamping force is 40N and the specific fluid flow rate condition Next,the contact position wear amount of the heat transfer tube and the anti-vibration strip is 0.3972 mm³,the wear depth is 0.006 mm,and it has not reached10%of the wall thickness.The failure probability in this state is 8.064×10^-6.?3?Considering the randomness of the parameters such as the aperture difference and the diameter of the heat transfer tube,the reliability analysis method is used to establish the prediction method of wear failure,and the reliability index is obtained for the gap between the heat transfer tube and the anti-vibration strip,the diameter of the heat transfer tube The sensitivity of other parameters.The results show that the gap Ce between the heat transfer tube and the anti-vibration strip and the fluid elastic stability constant?have a greater impact on the life of the heat transfer tube.In the actual application of the project,the processing level is improved to control the standard deviation of the pore size difference.?4?With the continuous reduction of the clamping force to 0,the amplitude of the vibration of the heat transfer tube is getting larger and larger,and the edge contour of the heat transfer tube peeling pit is gradually blurred,and the overall peeling phenomenon occurs,and the wear is becoming more and more serious.In the reliability analysis,it is considered that the gap between the heat transfer tube and the support is a key factor that affects the wear life.When the gap between the heat transfer tube and the anti-vibration strip is increased,the wear scar area also gradually increases.The gap is 0?m and 1?m,and the worn surface presents a typical partial slip zone optical mirror morphology,that is,the darker color edge sliding area surrounds the lighter color area.When the gap is 2?m,the area of the wear scar gradually increases,and the wear becomes more serious.