| Air preheater is an equipment,it can reduce the boiler heat loss and improve the combustion efficiency.In fact,it can use the boiler fuel combustion,which came from the high temperature exhaust,to heat the cold air before it get into the boiler.In practical operation,economy and safety of boiler unit are seriously affected by sealing performance(air leakage rate).The corrugated plate elastomeric seal component(corrugated plate component)studied in this paper is one of the many air preheater seal components.The corrugated plate elastomeric seal component(corrugated plate component)studied in this paper is one of the many air preheater seal components.Fatigue performance of the corrugated plate component directly reflect the change of the compaction force during the long-term continuous work available under the condition of the seal,thus affecting the overall heat transfer efficiency of the air preheater and downtime maintenance cycle,so the fatigue performance of the corrugated plate component has important practical application value.The corrugated plate component of air preheater is made of S316L material with good welding characteristics through rolling forming process and assembled and connected by spot welding process.In order to study the effect of the solder joint structure parameters on the air preheater corrugated plate components,in this paper,the reasonable way of solder joints modeling is chosed after comparing.And in order to study the simulation calculation and analysis of static strength and fatigue life of the corrugated plate component,ANSYS software is uesd,and based on the study,the corrugated plate component solder joint structure parameters are optimized.And the physical experiment of the fatigue life is carried out by using the test bench,at the same time,the reliability and rationality of optimization results is verified.The specific research process and results are as follows:First of all,the adjacent two simple seal model,for example,the Create point,rigid beam element method and mark surface method are used to establish,the finite element model of solder joints,and the simulation calculation are conducted respectively,the simulation results under three different modeling methods are compared,based on the efficiency of modeling,simulation speed and simulation precision,Create point and mark surface modeling method are selected as a solder joint model establishment method in this paper,the results showed that:the establishment of solder joint model based on mark surface method for simulation and the selection of solder joint structure parameters according to the results will be relatively conservative and highly stable.Regardless of the diameter of solder joints,the Create model of the ANSYS is used to establish the finite element model of the solder joint modeling,and applying the model 200 N loads is applied on the model,based on the equivalent stress,the simulation calculation has been carried on single row,multi-row and triangle arrangement of solder joints,and the double factors not repeat the test is used to analyze the results of variance analysis method.The results show that when the solder joint spacing is less than or equal to 75.4mm,the equivalent stress of corrugated plate has no definite change trend.This may be because the solder joint spacing is too small,resulting in the overlapping effect of the equivalent stress concentration area near the solder joint When the solder joint spacing is equal or greater than75.4 mm,the stress on the corrugated plate will increase as the solder joint spacing increases.The reason may be that the increase of solder joint spacing,resulting in the solder joint stress concentration affected by the region separated larger,weakened mutual superposition effect,and the number of solder joint reduction,a single solder joint to bear increased load;More welding conditions,factors"solder"horizontal spacing of equivalent stress simulation results of variance F_A is 54.46,greater than the significance level critical value of 3.15,shows that the change of corrugated plate component equivalent stress will produce significant influence,and the factors of"solder joints row number"F_B is1.04,the simulation results of the variance is smaller than the critical value of 4.6,shows that there is no significant effect;When the solder joints of the first and the third solder joints are left and right by 10 mm,and the left and right solder joints of the second row are left and right by 37.2 mm,the equivalent stress of the corrugated plate component is the minimum,about 25 MPa,and its corresponding simulation fatigue life is 7.89E6 times.Furthermore,the model of solder joint diameter is established by the imprinting surface method,and the simulated calculation and variance analysis of corrugated plate components with different solder joint diameters and arrangement patterns are conducted with the equivalent stress as the object.The results show that the variance calculation results corresponding to the factors of"solder joint diameter"and"solder joint horizontal spacing"are all less than the critical value under the condition of single row welding,indicating that the changes of these two factors have no significant effect on the equivalent stress of corrugated plate component in general.Solder triangle arrangement,under the condition of variance calculation shows that spot size has no significant effect on the equivalent stress of the corrugated plate component,but the F_N of equivalent stress results of factors"solder"horizontal spacing corresponding to the variance is 4.17,is greater than the critical value of 3.85,showing the factors on the corrugated plate component equivalent stress has a significant effect,reason may be that the solder joint triangular arrangement,improved the corrugated plate component mechanical characteristics,change will lead to solder joint level spacing of corrugated plate component equivalent stress is more noticeable impact.Finally,the simulation results are verified by physical experiments.The results show that the actual fatigue life of the corrugated plate component exceeds 3.0E7 times under the condition of single row welding,the left and right edge of the solder joint is 10 mm,the top and bottom edge are 4 mm,the horizontal distance of the solder joint is 70 mm,and the diameter of the solder joint is 5 mm.Under the condition of triangular arrangement,the left and right margins of the first row of solder joints are 10 mm,and the distance between the center of the solder joints and the upper boundary is 3.5mm.When the left and right margins of the second row of solder joints are 42.65 mm,the center of the solder joints is 4.5 mm from the upper boundary,the diameter of the two rows of solder joints is 2 mm,and the horizontal spacing of each row of the two rows of solder joints is 65.3 mm,the physical experiment shows that the actual fatigue life of the corrugation plate component exceeds 2.0E7 times at this time,meeting the requirements of the working condition.At the same time,the physical experiment also proves the feasibility of the imprinting surface method to establish the finite element model of solder joint and to carry out the simulation.By comprehensive comparison of the cost performance of fatigue life in the above two arrangements,it is found that the cost performance of fatigue life in the latter welding mode is the best and far meets the requirements of working conditions. |
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