Research On Underwater Performance Analysis And Optimization Of Heavy Amphibious Rescue Equipment And Its Propulsion System

Amphibious equipment,as a special vehicle,is not only related to the smooth operation of the rescue mission,but also to the life safety of the rescuers and the rescued.In view of the characteristics of China’s disaster relief needs,such as complex terrain and high proportion of flood disasters,it is of great practical significance to develop heavy amphibious rescue equipment and carry out water performance analysis and optimization.In this paper,the following research work is carried out on heavy amphibious rescue equipment:Based on hydrodynamics and numerical analysis,the overturning situation of articulated track,an amphibious rescue equipment developed in this paper,is discussed.The position interval of centroid,the depth of draft and the reserve coefficient of buoyancy under different load weights are analyzed.The position of the center of buoyancy under different floating states,the metacentric radius and the high value of stability under full load were obtained.The dynamic stability analysis of single car body is carried out under two conditions with or without sealing.The results show that the maximum hew moment of single car body under two conditions increases with the decrease of center of gravity.Based on the analysis of the resistance characteristics of articulated tracked all-terrain vehicles,the hydrostatic resistance prediction was carried out by using FLUENT software.The qualitative resistance characteristics of all-terrain vehicles were obtained by preliminary analysis,and the simplified model of vehicles with high prediction accuracy and calculation efficiency was determined through simulation and comparison,and the driving conditions of all-terrain vehicles under different load masses(36,44,52,60t)and different water driving speeds(0.5,1,1.5,2,2.5,3m/s)were simulated,and the wave height,vehicle circumferential flow and water resistance were analyzed,and the results showed that The driver’s exposed distance is required to be not less than25 cm under the condition that the driver’s cab can intuitively and clearly observe the situation outside the car;Moreover,the resistance of the vehicle is positively correlated with the load mass and speed.Research on drag reduction and growth rate of articulated tracked ATV is carried out.Combined with the physical structure of the ATV,the water resistance of the ATV was simulated by five methods: closing all the walking mechanism,adding the wave plate,wave pressure plate,installing hydrofoil and connecting two carriages,and the specific design ideas and installation methods were given.The simulation results show that the drag reduction design should be mainly designed to prevent the wave plate.While ensuring the high matching degree with the vehicle body installation,good drag reduction and growth effect can also be obtained.Through the coupled analysis of the flow around the propeller,the installation position of the propeller was determined,and the structure of the propeller support was designed and optimized.The propeller selection work was carried out according to the resistance of the vehicle,and the coupling analysis of single propeller,two-propeller and the flow around the propeller and the body was carried out.The installation position of the propeller was determined based on the previous generation model.Finally,considering the installation space,the specific propeller support is designed.