| Tank truck is an important constituent part of transport vehicle, which is widely used in the fields of liquid transportation and fire-fighting. For lately years, with the fast development of fire-fighting industry, the container capacity of the fire tank truck almost reaches to the upper limit of road transportable vessel. Because of the liquid goods of the tank truck, it sloshes hardly once the driving situation is changed, that makes the position of gravity centre changing all the time and the weight of front shaft and tail shaft of vehicle being not evenly divide and unstable. Liquid-sloshing has bad effect on driving stability, steering stability, braking performance, and security performance of the tank truck, especially for the heavy tank fire truck with a partially filled container. Worse but true, liquid sloshing is one of the most significant factors that cause tank truck accident as turning over. Research has indicated that the probability of causing accident of tank truck with half-filled liquid is 10 times than a truck with rigid goods. Therefore, it has the important practical significance and engineering value to research dynamics characteristic of liquid sloshing and baffles which are assembled in tank to enhance the longitudinal stability and controllability of sloshing.Previously most of the containers of tank trucks are analyzed in statics. With the raise of container's capacity and truck's speed, the dynamics pressure of liquid-sloshing has more influence on the tank truck's performance, such as driving stability, steering stability, braking performance, security performance and tank structure. And how to control sloshing is one of the bottleneck problems of designing medium and heavy tank fire truck. Former study of dynamics behavior of liquid sloshing of transportable tank focuses on horizontal cylindrical and elliptic cylindrical containers. But until now no reports about the car-carrying rectangular tank have been observed. By a special purpose motor company for designing a fire-truck with 12-ton water-tank, the thesis is the first time study on this field. The paper simulates the dynamics of longitudinal behavior of liquid-sloshing by builds a mathematical sloshing model, gets some sloshing dynamics regularity, and offers data for optimization design of the new structure rectangular tank of fire trucks.The main works of the thesis are followed:(1) Based on the theory of liquid filled systems dynamics, it builds a mathematical sloshing model that combines VOF and standard k-εequations with the simplified 3D model of rectangular tank under the driving features of the fire truck.(2) A three-dimensional vertical cylindrical tank with different liquid-filled is simulated under the mathematical sloshing model by software ADINA. The results of natural frequencies agree well with the experiment and calculation values, which confirm the finite element analysis is in reason.(3) Simulation of longitudinal liquid-sloshing with different speed and braking acceleration under the rectangular tank without baffle. The relationships between front/back header pressure and different braking accelerations are analyzed. And the sloshing motions with different liquid filled are carried out.(4) Simulation of longitudinal liquid-sloshing with different effective baffle areas and different baffle numbers under the rectangular tank. The sloshing motions with the tank setting without baffle, one baffle and two baffles are compared. By summarizes the effectiveness of the baffles in the tank, the suggestion about optimization design are provided.
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