The Study And Thermal Conductivity Model For The Oxide-insulated Oil Nanofluid

Nanofluid is a new type of fluid, it can effectively improve the performance of the coefficient of thermal conductivity of the fluid, and draw many researchers attention. And insulating oil because of its very low thermal conductivity coefficient, which restricted the miniaturization volume of the instrument and limit the more efficient way efficiency of the energy conversion. In order to effectively improve the thermal conductivity of insulating oil, This article will use the nano fluid to improve its thermal conductivity. In this article, the hydrothermal method was used to prepared smaller grain diameter and stability ZnO nanometer scale particles, the ZnO particles scattered to pure25#insulation oil, thus different volume fractions of nanometer ZnO insulation oil-base fluid was preparaed. Based on the transient hotline method, the ZnO insulation oil-base nanometer fluid thermal conductivity was measured, and the results show that the thermal conductivity has12%improvement when mixed with nanometer ZnO particles volume fraction of1%pure oil. The paper also introduces grinded and modified Al2O3nano powder and AlN nano powder, added certain stabilizer in which and adopted two steps synthesis method to prepare good stability Al2O3insulation oil-base nano fluid and AlN insulation oil-base nano fluid. By measuring the two nano fluid of electrical conductivity and thermal conductivity, and the results show that the two types of nano fluid insulation performance are satisfactory, And Al2O3insulation oil-base nano fluid and AlN insulation oil-base nano fluid, their coefficients of thermal conductivity are about20%of the increase when mixed with the volume of nano particles was1%. Finally, this paper based on previous studies, analyzed heat conduction enhancement mechanism of the insulation oil-base nano fluid’s, based on the insulation oil-base nanometer ZnO, Al2O3and AlN fluid thermal conductivity model, and compared with other models, it think that the model more identical with the three types of nano fluid experiment data.