Research On Heat Transfer Enhancement Characteristic Of Composite Tube Oil Cooler

In areas such as nuclear power, chemical industry, machinery, mechanical equipment can’t operate normally without lubricating oil, lubricating oil cooler is used to decrease the temperature of lubricating oil, ensuring the safety of the equipment plays an important role.All the equipment as much as possible save space somewhere, the ordinary light tube heat exchanger with big volume, low thermal efficiency , cannot meet the requirements. In order to realize the miniaturization of oil cooler, the heat transfer enhancement technology is needed,three-dimensional overall pin fin tube is appropriate for the heat transfer enhancement of lubricating oil with high viscosity.The oil cooler on the ship uses seawater as coolant, in order to prevent corrosion, the material contacting with seawater must be titanium. Existing technology can’t processing pin fins on titanium tube. Realise the miniaturization of lube oil cooler without enhancement heat transfer is impossible. In order to satisfy the heat transfer enhancement of high viscous fluid,at the same time, the surface contacting with water for titanium, this paper designed a kind of strengthening heat transfer components. And the composite tube type oil cooler (for short "F")is made. With 68 # turbine oil and water as heat transfer medium, the thermal hydraulic experimental study of F is studied. Within the scope of the experiment, the total heat transfer coefficient of F is 580 ～ 810 W/(m2·K), and compared to ordinary light tube heat exchanger under same conditions (for short "G") ,enhanced heat transfer effect is remarkable. Through the analysis of experimental results, fitting out of the heat transfer and resistance associated type, and the error analysis, fitting values with the experimental errors are within 10%.In order to study the heat transfer enhancement of F’s features, a similar structure pin fin tube oil cooler (hereinafter referred to as "Z") for the thermal-hydraulic experiment is designed. The heat transfer and resistance characteristics of F, G, Z is compared.Analyzes the factors that influence the heat transfer has guiding significance for design of oil cooler.Considering the the limitations of Webb evaluation criterion , grey decision is used to value the comprehensive performance of different types of lubricating oil cooler . The results show that F,which has compact structure, high heat transfer efficiency and good comprehensive performance ,has a good application prospect.On the basis of experiment, enhancement heat transfer mechanism of the pin fin tube is studied. The temperature field distribution on the pin fin issolved, and the structure parameters of pin fin tube for enhancement heat transfer is analyzed. Finally, through the analysis of flow characteristics, the enhancement heat transfer mechanism of the lubricating oil cooler is studied.