The Numerical Simulation And Experimental Research On Heat Transfer Performance Of Pure Counter-current Oil Cooler

In current society, the situation energy crisis and environmental problem is becomingmore and more intense, so people pay more and more attention on the work of low-carbonenergy, especially developed in high efficiency energy-saving heat exchange equipment ofindustrial application. Twisted tube pure counter-current oil cooler is a new kind of highefficient oil cooler, which is made by a new type of high efficiency and energy saving heattransfer tube-twisted tube.The heat transfer performance and flow resistance of twisted tube pure counter-currentoil cooler in both shell side and tube side are investigated by the means of theoretical analysis,numerical simulation and experimental testing in this paper.The influence factors of the heat transfer performance and flow resistance of twisted tubepure counter-current oil cooler is proposed. There are some problems appeared in the processof testing.According to these problems the solutions are put forward. This paper makes astudy of the work includes the following aspects:1. The heat transfer and flow performance of round tube, oval tube and differentparameters twisted tube are measured in the single tube experiment system, the heat transferperformance of oil cooler is also investigated. The result show that at the same Re twistedtube have good heat transfer performance and flow characteristic in the tube side compared tothe round tube. Along with the growth of Re and A/B, the Nu and ΔP become bigger,but the ηfirst increases, then decreases. The smallar of the S and the bigger of Pr is, the better of heattransfer enhancement performance. Meanwhile, the heat transfer enhancement performanceof twisted tube pure counter-current oil cooler is researched. The result show that comparedto the round tube oil cooler, the twisted tube pure counter-current oil cooler have good heattransfer performance and flow characteristic in the shell side. And the longer of the twistand the bigger of the crushed flat rate is,the worse heat transfer performance and flowcharacteristic of shell side of twisted tube pure counter-current oil cooler.2. The experiment studied the heat transfer performances and flow characteristics ofround tube and twist tube on the single tube test platform. The results show that the αand ΔPof twist tube are both higher than that of round tube on the same flow rate，especially at low flow speed. Theηof twist tube decreases as the Re increases，however，the heat transferenhancement is above20%higher than round tube when the Re is less than10000. TheαandΔP are both decrease as the S increase gradually. What’s more，the total heat transferperformance of twisted tube pure counter-current oil cooler was tested on test platform inWuhan New World Refrigeration Industry Co., LTD. The results show that the total heattransfer performance of twisted tube pure counter-current oil cooler is improved as theincrease of the flow rate and the inlet oil temperature.3. This paper presents some solutions to solve the problems in the test process of twistedtube pure counter-current oil cooler. As shell cross-sectional area is too small，The paperproposed that using Twisted Tube of Trifoil Cross Section instead of twist tube. Andnumerical simulation is carried out to study the shell side performances of Twisted Tube ofTrifoil Cross Section too. The results show that the shell side Nu andΔP of Twisted Tube ofTrifoil Cross Section is higher than that of twist tube at the same Re；the shell side α andΔP ofTwisted Tube of Trifoil Cross Section increases obviously compare with twist tube at thesame flow rate. The solution of paddle installation to solve the problem of flow leakagebetween tube bundles and cylinder in twisted tube pure counter-current oil cooler is proposedin the paper.By the experiment research and computer simulation on the heat transfer performanceand flow resistance of twisted tube pure counter-current oil cooler in both shell side and tubeside. Discusses the influencing factors of the heat transfer characteristics twisted tube and purecounter-current oil cooler and supply reference for further research on the heat transferperformance of twisted tube pure counter-current oil cooler.