Numerical Simulation And Optimization Of Internal Flow Field Of ACV

Hovercraft which is the most complicated ship form in hydrodynamic feature is a high-performance shipping and supported by static air pressure.The skirt-cushion system of being composed of draught fan,wind tunnel,skirt,and air cushion,then it determines lifting performance,stability,and rapidity of Air Cushion Vehicle(ACV).Also,the skirt-cushion system is a significant structure,which is different from other shipping,and the most closely related to the overall performance.In this paper,based on the reference of the parent ship of the processing program,which is “22 passenger spaces Air-cushion Vehicle”,it does a series of normative computing for lifting performance,and also analyzes the influences that skirt-cushion system brings to ACV.On the premise of accuracy of calculation result,this paper rational simplify the parent ship's skirt-cushion system and does 3D-modeling,and it uses CFD method to do numerical stimulation calculation for internal flow distribution.Finally,in contrast CFD result to the standard number of value,the rate of error is less than 7.0%.Simultaneously,this paper gets the change law of main parameters from its result by using the method of CFD calculates and analysis the installation position of spoiler,the installation position of flow deflector,and the influence of the curvature on the main parameters of the internal flow distribution of ACV.Aiming at shortage of peak power and gasbag pressure less than standard value,this paper proposes three plans which are setting up spoiler in gasbag,setting up flow deflector in draught fan entrance,and setting up spoiler and flow deflector at the same time.According to the result of CFD computing approach,by setting up spoiler at a distance of 465 mm left wall from draught fan entrance in gasbag,gasbag pressure increases from 1.146 to 1.226 that is 6.98%,,and pressure ratio of bow and stern increases from 0.993 to 1.056 that is 6.3%.That extremely improves the air-cushion hovercraft over-peak capacity.Also,by setting up curvature ?=1.43 flow deflector at distance of 265 mm from same area,gasbag pressure increases from 1.146 to 1.235 that is 7.77%,and pressure ratio of bow and stern increases from 0.993 to 1.063 that is 7.0%.Although setting up spoiler and flow deflector at the same time can enhance gasbag pressure and over-peak capacity,due to interaction of spoiler and flow deflector,optimized result is unstable.To sum up,this paper suggests that by using either spoiler or flow deflector can improve the internal flow distribution.The calculation approaches and optimized programs,meanwhile,will bring a significant benefit for design of ACV,and has crucial reference value in the future.