沼肥采运车储罐动力学数值模拟与相似模型试验

为满足沼肥采运车的工作效率,设计12 t大型车载式沼肥采运储罐,并针对大型沼肥采运车运输沼肥遇紧急制动时,储罐内部沼肥剧烈晃动对壁面产生的冲击可能导致储罐及连接支撑结构损坏,为安全运输带来隐患的问题。该文采用VOF(volume of fluid)多相流模型对采运车紧急制动时不同充料比下储罐内沼肥晃动进行分析和数值模拟,得出采运车的最佳运输充料比范围0.8~0.9;利用CATIA有限元分析模块在储罐三维模型上建立各零部件间具有联接和力传递关系的有限元模型,根据采运车工况,施加约束及储罐前封头和前防浪板所受冲击载荷峰值最大时的载荷边界条件后进行计算,依据计算结果调整储罐设计并优化结构,重新计算得到储罐的变形和应力分别为6.25 mm、136 MPa;运用相似理论量纲分析法确定储罐模型的几何尺寸及试验参数,模型试验中前防浪板迎峰面所受的冲击力计算值与原型中的数值模拟值存在近似1:64的比例关系,模型试验结果可推广至原型。研究为大型沼肥采运车储罐设计提供了可行的解决方案,同时也为类似运输罐车的研究提供参考。

Numerical simulation of dynamic and similarity model test of tank in biogas fertilizer transport truck

Abstract: Along with China methane industry development, processing and utilization of biogas residue is an urgent need. Past studies show that biogas residue fertilizer is a high quality liquid organic fertilizer and biological pesticide. Biogas residue fertilizer transportation and fertilization in the field need biogas residue fertilizer transport tank truck. While the acres of the fertilizer application rate in the field are as high as 50 t/hm2, thus in order to improve the shipments and using efficiency of tank truck, development of a large-scale biogas residue tank truck is essential. During transportation of biogas residue fertilizer, tankers will experience starting, acceleration, constant speed, the emergency brakes driving conditions. When the tanker driving state changed, biogas residue fertilizer is forced by inertial to cause rock, which has the impact to the storage tank wall surface, and the oversized impulse causes the storage tank structure to be damaged, resulting to biogas fertilizer leakage, which brings the danger for the safe transportation. However in the driving conditions, emergency brake driving conditions will lead to the biggest damage to the tank. When a large tanker for carrying biogas residue fertilizer suffers emergency braking in its transportation of biogas fertilizer, the huge attack on the wall from biogas fertilizer's violent sway may result in damage on tank and its structure, which causes potential crisis on safety in transportation. In this paper, our results showed that the best transportation filling ratio for a tanker was in the range of 0.8?0.9 by making an analysis and numerical simulation of biogas fertilizer's sway in the tank in different filling ratios when tanker was emergently braked using VOF multiphase flow model. We established a finite element model in which there was a link-up and force delivery among components on a 3D model using CATIA finite element analysis module. We calculated the basis of tanker's actual working condition, restriction implemented and the maximum loading limit of the attack that the tanker's front seal and front washboards can support. Then we adjust tank's design and refined structure according to the computation result, and concluded that the deformation and string of tank was 6.25 mm and 136 MPa respectively. After that, we defined the geometry size and experiment parameters of tank model using dimensional analysis method of the similar theory. When the parameter design was finished, we carried out the prototypical tank trial manufacturing. After that, a high-speed camera was used to shoot biogas residue flow state in different filling ratio of the tank and at the same time high-frequency dynamic response of the pressure sensor was used to test wave proof plate. In the experiment, it was calculated that the ratio of attack from the peak surface of front washboard and the numerical simulation result in prototype was nearly 1:64, which meant that the experiment result can be applied on prototype. This paper provided accessible solution for design of large tanker's tank which carried biogas residue fertilizer and provided reference for design of tank of similar transportation tankers.