Study On Heat Transfer Enhancement And Evaluation Method Of High Efficient Oil Cooler

Oil cooler is widely used in machinery industry, which has the large volume of generally heat exchanger with different kinds of structure and enhancement methods. In this paper, the heat transfer and resistance performance of laminated heat exchanger are researched by numerical simulation and experiment. The flow and heat transfer of fluid in shell are analyzed here with CFD simulation software: investigating the effect of fin spacing, fin thickness and tube pitch on the performance of laminated heat exchanger; contrasting the characteristics of laminated heat exchanger with transverse and longitudinal flow stream. The accuracy of numerical simulation is verified by experiment with laminated oil cooler; analyzing and comparing the heat transfer and resistance performance of laminated oil coolers with different model and oil coolers with different structure, meanwhile reforming the laminated oil cooler. Put forward one kind of evaluation method which based on the oil cooler heat transfer cost, and takes application in the experimental test to verify its rationality. The main work and conclusions are as follows:(1)Uneven distribution of fluid flow between the fins, stagnant zones exist after the tubes; the temperature of finned surface is higher than that of base tube, the farther the distance from the base tube, the higher temperature of the finned surface, resulting in lower fin efficiency; comparative analysis the effect of wing spacing and fin height on the heat transfer and pressure drop characteristics.(2)Test on seven oil coolers which have the same fin structure, analysis the results and found that the shell diameter, baffle spacing is independent on heat transfer and friction factor fund heat factor j, the correlations of j and f are obtained by the result of experiment.(3)Experimental comparative study for laminated oil coolers, pin-fin tube oil coolers and threaded pipe oil cooler. Laminated oil cooler excellent overall performance at low flow, But the deterioration in its overall performance with the flow increasing. The performance of pin-finned oil cooler is well, which can able to adapt to a variety of traffic situations. Threaded pipe oil cooler has valuable of applications in large flow because pin-finned oil cooler has some problems such as high manufacturing costs and pin fin easily broken.(4) The factors which affect the heat transfer performance of oil cooler are classified. Defined the thermal dimensional KA as the feature number of heat transfer capability of the oil cooler, and then presents a performance evaluation method based on the oil cooler heat costs which use thermal dimensional unit manufacturing costs for evaluation. The evaluation method Consider its heat capacity and manufacturing cost of oil cooler, and provide a basis for the design and selection of oil cooler.