车载LNG气瓶烘箱CFD分析及优化

CFD analysis and optimization of vehicle LNG cylinder oven

车载LNG气瓶烘箱内温度的大小和均匀性直接决定了气瓶表面温度分布,对抽真空效果影响很大,是制造优质LNG气瓶的关键。但车载LNG气瓶烘箱体积较大,内部流场实验测试难度大、成本高。为快速得到烘箱内的温度分布,采用CFD方法对烘箱内流场进行数值模拟,并进行了烘箱管道布局优化。结果显示,烘箱内末端热风流速明显大于前端,且热风穿过气瓶体时形成的旋涡阻碍了热量传递,导致烘箱内温度分布不均;烘箱内56个气瓶体和流场的温度分布规律相似,表面最高、最低温度分别为143.4℃和129.6℃;设计了3种回风管道布局,烘箱内气瓶平均温度呈现Type1> Type2> Type0,且越靠近进风管道末端气瓶温度越高。

The size and uniformity of the temperature in the vehicle LNG cylinder oven directly determine the temperature distribution of the gas cylinder,which has a great influence on the vacuum and is the key to manufacturing high-quality LNG cylinders.However,the vehicle LNG cylinder oven has bulky volume and its internal flow field experimental test is difficult and costly.As to quickly obtain the temperature distribution of the oven,the CFD method is used to simulate the flow field of the oven,and the oven pipeline layout is optimized.The results show that the flow velocity at the end of the oven is significantly larger than that of the front,and the vortexes generated when the hot air passing through the cylinders obstruct the heat transfer in the oven,resulting in uneven temperature distribution in the oven.The temperature distribution of the 56 LNG cylinders is like the flow filed in the oven,the highest and lowest temperatures on the cylinder surface are 143.4 ℃ and 129.6 ℃ respectively.Moreover,three kinds of return air duct layouts are designed,and simulation results show that the average temperature of the gas cylinder in the oven is obviously,Type1> Type2> Type0,and the temperature of the cylinder closer to the end inlet is higher than that in the front.