| The existence of the fouling will greatly affect the efficiency of heat exchanger.Because the alternating elliptical axis tube has special internal structure, it can greatlyimprove the heat transfer efficiency. It is widely used in industrial production. A lotof researches have been studied the heat transfer characteristics of alternatingelliptical axis tube, but rarely on the fouling characteristics. This thesis would focuson the fouling characteristics of particulate fouling and its mixture with crystallizationfouling on the alternating elliptical axis tube.Firstly, in order to study the law of fouling of magnesium oxide nano-particles inthe alternating elliptical axis tube, according to the particulate size, particleconcentration, liquid velocity and temperature, we have conducted several groups ofexperiments on the alternating elliptical axis tube in this paper. The results show that,in the same conditions, the smaller particulate size, the greater fouling rate andasymptotic value of fouling resistance. The fouling rate and asymptotic value offouling resistance increase with increasing concentration and decrease with theincreasing flow rate. The higher inlet temperature, the smaller asymptotic value offouling resistance is.Secondly, with the purpose of studying on the interactive law of crystallizationand particulate in composite fouling, the composite fouling characteristics inalternating elliptical axis tube has been experimentally studied under differentconditions and working fluid parameters. The results show that, the calciumcarbonate can inhibit the formation of the composite fouling. The fouling rate andasymptotic value of composite fouling resistance decrease with increasingconcentration of the calcium carbonate, and increase with increasing concentration ofthe nano-particles. The composite fouling resistance and fouling rate decrease withthe increasing flow rate. Asymptotic value of fouling resistance decrease with thehigher inlet temperature．... |
PDF Full Text Request