Potential Failure Mode Analysis And Optimization Of Shell And Tube Heat Exchanger Based On TRIZ

Shell and tube heat exchangers(hereinafter referred to as heat exchangers)are widely used because of their strong points such as simple structure,easy manufacture and convenient operation.However,in the actual operation,the heat exchangers often fail mainly due to cracking,resulting in a shortening life;When the traditional failure analysis methods are used to analyze the failures of heat exchanger,it is affected by the analyst’s brainstorming,the analysis processes are relatively ambiguous and lacks of specific guidance model,causing inaccurate results,as a result,enterprises often fail to accurately identify potential failures,and they can just maintain normal operation by simply replacing equipment and materials.In order to study the potential failures of the heat exchangers,the paper takes the heat exchanger of a polysilicon enterprise as the research object,determines the potential failures according to the actual working conditions and optimizes it to improve reliability,which is of great significance to reduce the operation failure of the heat exchanger and prolong the service life.In the light of the above problems,the paper analyzes the potential failures of the heat exchanger from the function and attribute of TRIZ,carries out the numerical simulation to further analysis and verify the potential failures of the heat exchanger,and finally,according to the simulation results,the optimization design is carried out to improve the reliability of the heat exchanger.The main content completed includes:First of all,in view of the shortcomings of traditional failure analysis methods based on brainstorming,drawing on the concept of reverse thinking in the anticipatory failure determination method,according to the interaction characteristics of component attributes from the functional perspective of TRIZ,five general models and application processes for analyzing potential failure modes and causes of the system are constructed,also a failure analysis method based on function-attribute is formed.With regard to the problem of attribute determination in the general models,an attribute search algorithm is formulated.Secondly,the functional model of the heat exchanger is established,and the relevant attributes of each component are obtained in line with the attribute search algorithm.The component units are determined by the function level calculation,and five general models are used to build the solution model,the potential failure modes and causes of the heat exchanger are acquired.Aiming at the problem of heat transfer capacity decline,the fouling deposition model is established,and the probability of heat exchanger failure causes of by dirt deposition is gained.Then,the simplified three-dimensional model of the heat exchanger is numerically simulated.According to the simulation results,the velocity,pressure and temperature changes of the fluid in the tube and shell side and the temperature changes in the solid domain are obtained.The results of the simulation analysis are compared with the failure causes analyzed by using the five general models to test the correctness of the five general models.Through comprehensive analysis,it is found that the baffles are an important structural factor to affect the reliability of the heat exchanger.Finally,with regard to the problems of the baffles,the gap height of the baffles is optimized,the results of shell side fluid simulation with gap height of 0.25 D,0.35 D and0.45 D are compared and analyzed,and points of special location are analyzed,the optimal gap height of the baffles is determined.