【作者】 朱宁；

【导师】 顾超华； 郑津洋； 韩武林；

【作者基本信息】 浙江大学 ， 能源动力（专业学位）， 2023， 硕士

【摘要】 氢能作为清洁环保、利用高效的二次能源,受到世界各国的广泛关注。氢燃料电池汽车具有低排放、低污染、能量转化效率高等优点,在氢能产业中具有广阔的发展前景。塑料内衬碳纤维全缠绕氢气瓶(Ⅳ型储氢气瓶)因其质量轻且耐疲劳性能和耐腐蚀性能优异,是车载储氢的重要研究方向,其安全性和经济性在实际应用中备受关注。国内对Ⅳ型储氢气瓶研究起步较晚,仍处于研发阶段,尚无大规模制造能力。Ⅳ型储氢气瓶的结构设计和优化方法尚不成熟,且对制造过程的工艺研究较少。本文针对容积为78 L的70 MPa Ⅳ型储氢气瓶进行了结构设计、固化工艺和结构优化研究,主要研究工作如下:(1)基于网格理论,对Ⅳ型储氢气瓶进行结构初步设计。基于纤维缠绕规律,根据设计容积要求对内衬结构尺寸进行设计。基于网格理论,根据工作压力要求对纤维缠绕层进行设计。通过三次样条函数封头厚度预测方法,预测了封头段缠绕层厚度,针对极孔处纤维堆积的问题,采取扩孔缠绕的方式减少了极孔两个带宽内的纤维厚度,建立了Ⅳ型储氢气瓶初步设计方案,并基于网格理论对初步设计方案进行强度校核。(2)基于服役性能,对初步设计方案强度进行校核,对Ⅳ型储氢瓶进行结构进阶设计。基于Hashin失效准则和复合材料损伤演化规律,通过ABAQUS用户子程序UMAT建立了Ⅳ型储氢气瓶服役性能预测模型。基于服役性能分析对初步设计方案进行强度校核,在136.0 MPa时已在封头段发生爆破失效。据此对气瓶结构进行调整,建立了Ⅳ型储氢气瓶结构进阶设计方案。分析了气瓶在工作压力下的应力状态和加载过程中纤维缠绕层的损伤演化行为。结果表明基体拉伸损伤首先发生在筒身段内侧螺旋向缠绕层,纤维拉伸损伤首先出现在筒身段内侧环向缠绕层。纤维拉伸损伤的出现滞后于基体拉伸损伤,损伤扩展速度较快。预测气瓶爆破压力为161.8 MPa,失效位置为筒身段。(3)面向气瓶的轻量化要求对气瓶的结构进行优化。讨论了缠绕角度和缠绕顺序对强度的影响规律,结果表明大角度螺旋向缠绕层对封头段强化作用较小,将环向缠绕层集中至内侧,将螺旋向缠绕层按缠绕角从小到大的顺序缠绕有利于提高筒身段强度。根据此规律对气瓶进行轻量化设计,将储氢密度从4.47 wt%提高为4.84 wt%。讨论了碳纤维性能提升对储氢密度的影响,采用东丽T700S、T800G和T800S作为纤维缠绕层材料,气瓶储氢密度达到6.01 wt%、6.21 wt%和6.66 wt%,可满足美国能源部(DOE)储氢密度达到5.5 wt%的要求。(4)对固化工艺过程中气瓶的温度场变化规律和影响因素进行研究,提出适用于本文气瓶结构的固化工艺曲线。基于热传导模型和固化动力学模型,建立了Ⅳ型储氢气瓶固化工艺温度场预测模型,分析了固化工艺过程中气瓶温度场分布规律,讨论了固化工艺最高温度和保温平台对内衬温度峰值的影响。结果表明由于固化反应放热,内衬温度峰值出现在缠绕层厚度较大的筒身段,且温度峰值高于固化工艺最高温度。内衬温度峰值随着固化工艺最高温度的增加而增加,增加保温平台数量有利于降低内衬温度峰值。对于本文的Ⅳ型储氢气瓶结构建议采用最高温度为160℃的三平台固化工艺曲线。更多还原

【Abstract】 As a clean,environmentally friendly and highly efficient secondary energy,hydrogen energy has received widespread attention around the world.Hydrogen fuel cell vehicles have broad development prospects in the hydrogen energy industry because of its advantages of low emissions,low pollution,and high energy conversion efficiency.Carbon fiber reinforced composite hydrogen storage cylinder with plastic liner(Type Ⅳ hydrogen storage cylinder)is the important research direction of vehicle hydrogen storage because of its lightweight and excellent resistance to fatigue and corrosion,but its safety and economy have attracted much attention.The domestic research on type Ⅳ hyrogen storage cylinder started late,is still in the research and development stage,and there is no large-scale manufacturing capacity.The structural design and optimization method of type Ⅳ hydrogen storage cylinder is not yet mature,and there are few studies on the manufacturing process.In this paper,the structural design,curing process and structural optimization of 70 MPa type Ⅳ hydrogen storage cylinder with a volume of 78 L were studied.The main content and conclusions are as follows:(1)Based on the netting theory,the structure of type Ⅳ hydrogen storage cylinder is preliminarily designed.According to design parameters of type Ⅳ hydrogen storage cylinder,based on the fiber winding law,the liner structure size is designed,and the winding layer is designed based on the netting theory.The thickness of winding layer of dome section is predicted by the cubic spline function dome thickness prediction method.In response to the problem of fiber accumulation at polar hole,the method of expanding-winding is adopted to reduce the fiber thickness within two bandwidths of the polar hole.The preliminary design scheme of type Ⅳ hydrogen storage cylinder is established,and the strength of the preliminary design scheme is checked based on the netting theory.(2)Based on the service performance,the preliminary design strength is checked,and the structure of type Ⅳ hydrogen storage cylinder is designed.Based on the Hashin failure criterion and the damage evolution law of composite materials,the service performance prediction model of type Ⅳ hydrogen storage cylinder was established by ABAQUS user subroutine UMAT.Based on the service performance,the strength of the preliminary design scheme was checked,and failure occurred in the dome section at 136.0 MPa.The structure of the cylinder was adjusted,and the structural design scheme of the type Ⅳ hydrogen storage cylinder was established.The stress state of the cylinder under working pressure and the damage evolution behavior of the carbon fiber winding layer during loading were analyzed.The results show that the tensile damage of matrix first occurs in helical winding layer,and the tensile damage of fiber first occurs in hoop winding layer.The occurrence of fiber tensile damage lags behind matrix tensile damage,and damage propagation speed is faster.It is predicted that the burst pressure of the cylinder is 161.8 MPa,and the failure position is cylindrical section.(3)The structure of cylinder was optimized for lightweight requirements.The influence of winding angle and winding sequence on strength is discussed.The results show that large angle helical winding layer has little strengthening effect on dome section.It is beneficial to improve the strength of cylinder by concentrating the hoop winding layer to inside and winding the helical winding layer in the order of winding angle from small to large.According to this law,the lightweight design of cylinder is carried out,and hydrogen-storage capacity is increased from 4.47 wt% to 4.84 wt%.The effect of carbon fiber performance improvement on hydrogen-storage capacity was discussed.Using Toray T700 S,T800G and T800 S as filament winding layer material,the hydrogen-storage capacity of cylinder can reach 6.01 wt %,6.21 wt % and 6.66 wt %.(4)The temperature field variation law and influencing factors of the cylinder during curing process were studied,and the curing process curve suitable for the cylinder structure in this paper was proposed.The temperature field prediction model of type Ⅳ hydrogen storage cylinder during curing process was established based on heat conduction model and curing kinetic model.The temperature field distribution of cylinder during curing process was analyzed.The influence of the maximum temperature of the curing process and the number of holding section on peak temperature of liner was discussed.The results show that due to the heat released by curing reaction,the peak temperature of liner appears in cylindrical section,and is higher than the maximum temperature of curing process.The peak temperature of liner increases with the increase of the maximum temperature of curing process.Increasing the number of holding section is beneficial to reduce peak temperature of liner.For the structure of type Ⅳ hydrogen storage cylinder in this paper,it is recommended to adopt a process curve with maximum temperature of 160 °C and number of curing insulation platforms of 3.更多还原