Churning Loss Of Automobile Main Reducer Based On PLIC-VOF Algorithms

Improving the efficiency of automobile transmission and reducing fuel consumption is one of the key objectives to improve the quality of automobile products.As the main component of the total oil consumption of automobiles,the churning loss in the main reducer has always been emphasesed at home and abroad.The mechanism of the churning loss and oil consumption characteristics in the main reducer was studied by numerical calculation and simulation as well as experiment.Firstly,the two-dimensional disk churning model was established based on PLIC-VOF algorithm.The governing equation was calculated by using the finite difference method and staggered grid method.The two-dimensional disk model and the two-dimensional gear model were respectively simulated by Fluent.The rationality of simplifying the disk model and the feasibility of the PLIC-VOF algorithm were verified by comparing the oil distribution and the resistance moment curves with the rotational speed.The two-dimensional PLIC-VOF algorithm was suitable for calculating the churning power loss of the gear at the low speed.The churning power loss of the gear increased with the rotational speed and the immersion depth as well as the viscosity.The viscosity had the greatest influence on the churning power loss of the gear.Secondly,considering the influence of the side surface of the gear on the flow structure,the three-dimensional disk churning loss model was established based on PLIC-VOF algorithm.Then the three-dimensional gear simulation model was also established.Moreover,the churning loss in three-dimensional gear was calculated by using the Realizable k-? turbulence model and VOF method in Fluent software.Because disk model based on PLIC-VOF algorithm has not considered the influence of the tooth shape,the churning power loss of disk model was slightly smaller than gear model based on Fluent.Thirdly,in order to further study the oil flow state in gear working process,the experiment system was build to text power loss of gear at different speed and viscosity as well as immersion depth.The results of three-dimensional disc calculation model and three-dimensional gear simulation model were similar.However,because of the meshing loss of gears and oil consumption of bearings during the experiment,the experimental results were bigger.In a word,aiming at churning loss of gear,this Paper deeply conducted theoretical research from two-dimensional model to three dimensional model based on PLIC-VOF algorithm and Fluent as well as experiment.The oil distribution and variation law of gear churning loss at different rotational speed and immersion depth as well as viscosity were analyzed.That not only provides theoretical support for gear churning loss mechanism,but also has very important practical significance for reducing automobile fuel consumption and improving transmission efficiency.