Optimization Design Of Ship Tractor Hull Based On CFD

As a special equipment of agricultural mechanization in paddy field in China,ship-type tractor can combine "floating" with "sinking",and "sliding" with driving effectively through hull.This article in the related knowledge of ship mechanics and fluid mechanics,based on CFD VOF air and mud two phase flow,a simulation model of hull ship tractor is studied under different speed of hull by friction drag,wave drag and the influence of free liquid surface wave high,through the study of the optimization design of hull,reduce the resistance of hull and reduce the free liquid surface wave height.1.In order to improve the working performance of ship type tractor,reduce the tractor hull in a deep mud feet of frictional resistance in the paddy field,based on CFD algorithms VOF air and mud planing hull model of two phase flow,the research on the hull boat tractor speed is affected by the friction resistance,by changing the number of curved hull plate and the radian amplitude on the drag reduction effect,and optimize the design of single arc hull.The results show that when the forward speed of the single-arc hull is 2m/s and the radian amplitude of the hull bottom is 35 mm,the single-arc hull has drag reduction effect,and the drag reduction rate reaches 6.8%.2.Wave formation is easy to occur in the free liquid surface near the hull of ship-type tractor during cultivation,which seriously affects the survival rate of seeding.In order to reduce the tractor hull wave formed in the process of cultivation,based on CFD algorithms VOF air and mud planing hull model of two-phase flow,the ship of the tractor forward speed,hull length-width ratio on the hull are the wave-making resistance,free liquid surface wave height and wave action area,the influence of the optimization design of concave type of hull.The results show that the wave-making resistance,wave-making height and wave-making area increase with the increase of velocity.When the forward speed of concave hull is 2 m/s,the wave height of concave hull relative to flat hull bow and stern decreases by 0.052 m and 0.028 m respectively.The attenuation rate of ship traveling wave is 3.7% and the wave resistance of sunken hull is the least when the length-width ratio is 19.3.In order to reduce the friction resistance and wave height on the hull of ship-type tractor during paddy field cultivation,the influence of forward speed of ship-type tractor on the friction resistance,wave resistance and wave height on the hull of ship-type tractor is studied,and concave arc hull is optimized.The results show that the frictional resistance and wave-making resistance of the hull and the wave-making height of the free liquid surface increase with the increase of velocity.When the forward speed of concave arc hull is 2m/s,the wave height of concave arc hull relative to flat hull bow and stern decreases by 0.047 m and 0.025 m respectively.The drag reduction rate reached 5.3%.Finally,the soil trough experiments of the above three experimental ship models are carried out to verify the total resistance of the ship,the wave-making shape of the free liquid surface and the attenuation rate of the ship traveling wave.The experimental results and the simulation results are basically consistent.This paper provides a feasible method to study the drag reduction of ship tractor hull and optimize the design of ship type.