In production application, the shell and tube heat exchanger is been widely used and it is mainly composed of shell, tube plate, heat exchange tube, gland, baffle plate and so on, for those material can be made of ordinary carbon steel, red copper, or stainless steel. During heat transfer, the hot fluid enters the joint tube of the gland, flows in the tube, and flows out of the outlet tube at the other end of the gland, which is called the Tube Pass; Another type is the fluid enters by the side of the tube and flows out from another side of the tube, which is called the Shell Pass.(the shell and tube heat exchanger may also work in opposite way, which means the cold fluid may also transfer to the hot fluid)