The Influence Factor Of Crystallization Fouling Formation On The Heat Exchanger Surface

The fouling does not only have effect on heat transfer efficiency, but also result in many technology and economy problems during the fluid flow process. At present, the fouling of heat exchange surface is the primary indicator for designing the heat exchanger. The academia of heat and mass transfer has paid attention the fouling negative effect to industry. The influence factors are systematically analyzed about crystallization fouling deposition through simulation and experiment.Based on the crystallization fouling deposition mechanism, the FORTRAN language describes the fouling deposition with continuity, momentum energy and mass transfer equation. It compiles the computational program for solving the mainly deposition rate, then it need to CFD software for calculation. The working condition is separately experiment and simulation. The fouling resistance of simulation is compared with the experiment result. In case of ignoring the induction period, the simulation result is in line with the experiment result, so the simulate method is feasible. The verification is not only in the circular tube but also in the rectangular channel and vortex generator channel.The various kinds of flow condition are calculated in the circular tube. The crystallization fouling deposition is related to wall temperature, concentration, fluid temperature and velocity in the circular tube. With the higher fluid velocity, the fouling deposition becomes lower. With the higher wall and fluid temperature, the fouling deposition becomes higher. With the higher concentration, the fouling deposition becomes higher. The circular tube of fouling resistance is more than the alternating elliptical axis tube and discrete double inclined ribs tube. The variation tendency of two tubes are same as the circular tube, but difference value of enhancing heat transfer tube resistance is more even than the circular tube.According to the heat transfer enhancement theory of vertex generator, the vortex generator can be laid out on the heat transfer surface. It can be researched that the vortex generator structures have effect on the crystallization fouling deposition. For effectively evaluating the vortex generator influence, it builds up the anti-fouling rate to illustrate. Through the simulation, the delta wing anti-fouling is the best, but the float point is the worst in our investigation condition.The chloridion and nitrate have effect on the crystallization fouling, so the phenomenon is researched with the experiment. Because the chloridion easily adsorb on the calcium sulfate surface, the fouling is difficult to coagulate on the heater surface. The fouling resistance of chloridion is less than the nitrate’s. When the two kinds of anion concentration become higher, the fouling resistance appears larger tendency. After analyzing the incidence relate between fouling resistance and water quality parameter, the order of parameters association is same between the two enhancement heat exchanger tubes, but the tube is different from enhancement heat exchanger tube. The structures of enhancing heat transfer tube will not only influent the water quality parameter variations, but also influent the resistance and parameter.