On the basic of the theories of thermal convection and turbulent flow as mentioned above, the three-dimensional models
of heat exchangers with different internal structures are put forward by fitting baffles. Among these internal structure, the
geometrical model of the heat exchanger including fishbone-shaped internal structure, accordion-shaped internal structure,
scatter-shaped internal structure are showed in Fig. 2a,b,c. The CFD simulation results including the temperature contour are
showed in Fig. 3a– c.