The Determination Of Grease Coefficient Thermal Conductivity And Study Of Grease Heat Transfer Performance

Grease is an important matter, people get calories and nutrients generally exists invegetable oil and animal fat, is a necessity in People’s Daily life, also has a wideapplication in industry. Coefficient of thermal conductivity is one of the importantparameters in thermal and physical properties of grease, all involved in the processof oil processing in the design of heat transfer equipment is a necessary andimportant basic data. Along with the development of new oil products and thedevelopment of oil processing process, due to the lack of the coefficient of thermalconductivity of new oil product data, and the coefficient of thermal conductivity ofsome existing oil data are mostly under120℃, and in a wider temperature range is adata and grease under the high temperature coefficient of thermal conductivity is asevere lack of data, it will severely restrict in oils and fats processing involved in theprocess of heat transfer equipment and related to the heat transfer of the accuracy ofthe design of the equipment. Therefore, with a kind of accurate and reliable methodfor determining oil coefficient of thermal conductivity and study the change rule andinfluence factors of thermal conductivity, the process of oil processing technologyand equipment design, and it is of great significance to guide the actual production.Coefficient of thermal conductivity of oil characterization is grease thermalmotion of molecules on the contribution of heat transfer, in the determination of thecoefficient of thermal conductivity of liquid oils and fats, how to avoid the influenceof natural convection heat transfer liquid or avoid the liquid is caused by heating ofconvection heat transfer, is very important for accurate determination of thecoefficient of thermal conductivity of oil. Hot disk analyzer is based on the transientplane heat source in thermal and physical properties of material coefficient ofthermal conductivity in the legal system into the instrument, the core part is theprobe, because the probe is the heat sensor, hence can effectively reduce the effectsof heat convection on the experimental results, in use process should also payattention to the influence of thermal contact resistance on the determination results.But the equipment is used in the determination of solid material coefficient of thermal conductivity, very few applications in the field of liquid thermalconductivity measurement, need through the experimental research, explore suitablefor the liquid thermal conductivity measurement probe, heating power and test time,lay a foundation for the accurate determination of the coefficient of thermalconductivity of oil.This study Hot Disk Hot property analyzer was applied to grease the coefficient ofthermal conductivity measurement, research conducted by the instrument in thedetermination of oil when the coefficient of thermal conductivity, you need to set upsuitable probe type, heating power and test time, research shows that: in the30-240℃, the coefficient of thermal conductivity of the peanut oil and soybean oil testingtime or the heating power increases with the increased slightly; Especially in hightemperature (>120℃), if the test time or heating power set is larger, can lead to oilconvection heat transfer, make the result of the experiment error is very big; Test thelonger, the greater the effect of convection heat transfer, the suitable test conditionsfor: under180℃using5465type probe radius of3.189mm, the heating power is30mW, the test time is5s; Above180℃using5465type probe radius of3.189mm,heating power of30mW, testing time is2s. Under the condition of the peanut oiland soybean oil were measured respectively in the coefficient of thermalconductivity of30-240℃, the experiment shows that the coefficient of thermalconductivity of the two kinds of oils and fats that increases with temperature rise,peanut oil thermal conductivity change range is0.1626to0.2566(unit: w/m·k),soybean oil, coefficient of thermal conductivity change range is0.1791to0.2568(unit: w/m·k). This research improve the coefficient of thermal conductivity of thetwo oil at low temperature data, fill in the oil at high temperature coefficient ofthermal conductivity data blank, for oil processing involved in the process of heattransfer for the process design and selection of equipment laid a foundation.