| Film evaporator is a new type of cooling devices which makes a combination of air and water. it makes the separated refrigerant condensate process by water-cooled condenser and cooling water cooling process by cooling tower together into one process, this improved film evaporator have several advantages such as compact structure, energy and water saving. Having aluminum-carbon steel composite tube application in the film evaporator can not only plays the advantages of efficient heat transfer of film evaporator, but also make full use of aluminum to avoid the corrosion of outside environment so that Substantially increase the useful life of the heat exchange tubes.Firstly, this paper makes a measurement about the thermal conductivity and thermal resistance of composite pipe. Secondly, the contrast experiment is made about the heat trans ferperformance between aluminum-carbon steel composite pipes and normal carbon steel pipes. It is resulted that the thermal conductivity of the aluminum-carbon steel composite pipe is15%lower than the normal carbon steel pipe, but the total heat transfer coefficient of aluminum-carbon steel composite pipe is only7.8%lower than that of ordinary carbon steel pipe. Finally, the experiment is made to research and analysis the heat transfer performance when apply the aluminum-carbon steel composite pipe in the film evaporator experimental platform. The experiment results show that thermal resistance is the subordinate factor which influences the total heat transfer coefficient which remains almost the same when thermal resistance changes.The series of experiments conclude that the composite pipe can completely replace the traditional carbon steel tube to be used in varieties of surface evaporators. At present, the composite pipe has been used in some air coolers and evaporators which belong to a company. It shows that the composite pipe has certain advantages on heat transfer performance, service life, factory cost with other congener products. |
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