Study On Heat Transfer Performance Of Propylene Glycol Nanofluid In Automotive Radiator

The coolant is an indispensable fluid for the cooling system.It is about 30%of the heat generated in the combustion chamber is emitted by coolant,so the heat transfer performance of the coolant is important.At present,the traditional coolant uses ethylene glycol as the base fluid,which has the problems of unstable performance,poor heat transfer,short service time and etc.And it will cause damage to the ecological environment.The researchers added nano-particles to the cooling fluid,significantly enhance the heat dissipation capacity of the fluid,thus improving the cooling rate and running speed of the engine and reducing the energy consumption.The propylene glycol nanofluid has the advantages of high boiling point,low condensation point,environmental protection and corrosion resistance.It has a broad application prospect.Firstly,the main factors that influence the heat transfer performance of nanofluids are identified.And then the influence of physical factors(particle volume fraction,particle type,particle size)and working factors(temperature and velocity)on heat transfer performance of the nanofluids in the automotive radiator is obtained through the experimental and simulation analysis.We have established the motion equation and energy equation of the nanoparticles,and analyzed the energy transfer caused by the particle motion,thus the mechanism of the effect of particle motion on the heat transfer performance was explored.The main research content of this article is as follows:1?The research scheme is designed,and the relatively stable nanofluids is prepared by the two step method and ultrasonic vibration.According to the empirical formula,the thermal physical parameters of the fluid are calculated.And a test bench for the cooling performance of the automotive radiator is built according to the test principle.2?According to the research scheme,the heat transfer performance test of nanofluids is carried out.The inlet and outlet temperature and wall temperatureof the radiator are measured.In combination with numerical calculations,the parameters that characterize the heat transfer performance of fluid are obtained.We have analyzed the variation rules of various parameters,and explored the influence mechanism of physical factors and working factors on the heat transfer performance of nanofluids.3?The three-dimensional mesh model of the flat tube is established,and the heat transfer and flow characteristics of nanofluid in the flat tube are simulated.We have obtained the temperature distribution and pressure cloud map,and analysed the change law of heat transfer coefficient while particle motion.is not considered.4?The equation of motion of the particles is established,and the average velocity of the particles is obtained.We have established the energy equation,and analyzed the energy loss that caused by the particle collision,thus the mechanism of the effect of the particle motion on the heat transfer performance is explored.The correctness of the influencing mechanism is verified by comparing the experimental results with the simulation results.This paper studies the heat transfer performance of nanofluids in automotive radiators,and comprehensively analyzes the influence of various factors on the heat transfer performance,which provides a theoretical basis for the practical application of nanofluids.