Multi-field Coupled Analysis And Optimization Design Of Tube Heat Exchanger In Steam Injection Boiler

Steam injection boiler is a key equipment of producing high temperature and high pressure steam,and its safety and high efficiency directly affect the economy of viscous oil recovery.The length of a tube heat exchanger,which is widely used in the Steam-injection boiler system with large structure size and complex stress distribution,is about 8.5 meters.Multi-field coupled numerical simulation method was applied to analysis the effect of flow,heat transfer and strength of structure.In the premise of the heat exchange capacity of the tube heat exchanger,using heat transfer enhancement technology to optimize the structure of heat exchanger and reduce its size as well as weight.This paper firstly presents a summary of heat transfer enhancement development in heat exchanger and the situation of the Multi-field coupled numerical simulation method used in the tube heat exchanger.Tube heat exchanger of steam-injection boiler used in the oil field has been studied and the model was erected,and then computational fluid dynamics software and finite element software were applied to analysis the whole model based on multi-field coupled model which included fluid field,temperature field and structure of the heat exchanger,the distribution of fluid field and temperature field were obtained.Multi-field coupled method was also used to analysis the tube heat exchanger under different operation parameters,and the distributed regularities of heat exchanger's stress and strain were obtained as well.Finally,the thermal and structure strength weakness point of the heat exchanger could be got and provided the theoretic foundation for improving design of the heat exchanger.Based on the above research,the numerical model of fluid and heat transfer in bellows was erected and parameterized modeling of heat exchanger was accomplished.Using heat exchanger,inner tube resistance and annular space resistance as evaluation indexes,four factors three levels orthogonal experiment of bellows was designed,and numerical simulation method was taken to analysis nine kinds of bellows and obtain the regulations of different structure parameters effected the heat exchange and resistance of bellows,and use a comprehensive method to determine the optimal structure parameters of the bellows.Multi-field coupled numerical simulation method was applied to analysis the optimal designed bellow,the results show that the size was largely decreased under the promise of the same heat exchange capacity of the bellow,and the loss of the resistance is not increased obviously,the structure strength meet the design requirement as well.This research could provide the theoretical basis for heat exchanger's design and practical application.