Study On Heat Transfer Performance And Optimization Of Extrusion Forming Process Of TA1 Internally Threaded Tube

With the development of the "double carbon" trend,enhanced heat exchange technology is becoming increasingly important and marine engineering is facing enormous challenges.In this context,the development of highly corrosion resistant,high performance heat exchange tubes has become particularly important.In previous investigations,complete TA1 internally threaded tubes have been successfully extruded using a hot extrusion method with a passively rotating threaded mandrel.However,it is not clear as to the excellent heat exchange performance of this tube.Therefore,in this paper,a numerical simulation study of heat exchange will be carried out around the inner tube structure in order to obtain a tube with better heat transfer performance.As the structure of the internally threaded tube changes,the corresponding extrusion die will also need to be changed.In view of the poor plasticity of TA1 and the difficulties in forming,it is necessary to optimise its extrusion process.The ANSYS Fluent numerical simulation software was used,firstly to check the independence of the mesh and to validate the computational model.Numerical simulations of heat exchange were carried out for different configurations of internally threaded pipes in the range of Re(Reynolds number)of 3200-9600 using water as the working mass.The enhanced heat exchange in the internally threaded pipe is explained by means of temperature and pressure clouds,and the mechanism of the enhanced heat exchange is also described by means of turbulent kinetic energy,velocity vectors and flow field diagrams.The effect of the structural dimensions of the internally threaded pipe,including the thread lift angle(10°-30°),the number of thread teeth(14-18)and the thread height(0.8-1.6 mm)on the pressure drop and Nu(Nurse number),is investigated and the PEC(combined heat transfer coefficient)is used as a criterion to obtain an internally threaded pipe structure with optimum heat transfer performance.The results of the study show that the pressure drop and Nu increase consistently with increasing Re.The increase in Nu is more pronounced for thread lift angles of 10° to 20°and slows down for thread lift angles of 20° to 30°.The PEC comparison shows that the best overall heat transfer performance is achieved with a thread lift angle of 20°.The increase in Nu is more pronounced for 14-18 threads and slows down for 18-22 threads.The increase in Nu is more pronounced for a thread height of 0.8-1.2 mm and less so for a tooth height of 1.2-1.6 mm.The PEC comparison shows that the best overall heat transfer performance is achieved at a thread height of 1.2 mm for internally threaded tubes.The overall analysis shows that the best overall heat transfer performance is achieved with a thread lift angle of 20°,18 thread teeth and a thread height of 1.2 mm.Deform finite element software was used to simulate an orthogonal extrusion of a newly constructed internally threaded tube,and the VRD value was used as a criterion for tooth formation.The minimum VRD value was 0.0139 at an extrusion speed of 1 mm/s and an extrusion temperature of 750°C.The initial data was fitted with an artificial neural network toolbox,and the VRD value was solved with the help of a genetic algorithm using the extrusion temperature and extrusion speed as variables and the VRD value as the objective function,resulting in a VRD value of 0.0135,an extrusion temperature of 728°C and an extrusion speed of 1.230 mm/s.The results showed that the VRD value was0.01366,with an error of 1.2%,and this was verified by extrusion tests.