基于LabVIEW的虚拟仪器技术在储氢合金活化和循环过程中的应用

Application of LabVIEW-based virtual instrument technology in activation and hydrogenation cycling of hydrogen storage alloy

储氢合金在活化和吸放氢循环实验过程中需要涉及对Sieverts装置中各部分阀门进行反复开关,以及对储氢合金的吸放氢循环次数进行记录。为了提高实验过程的效率和避免各类突发原因造成的实验失败,本文试图借助LabVIEW软件,利用实验室现有Sieverts装置硬件,实现储氢合金的活化处理,长期循环稳定性和粉化特征的测试功能,以满足储氢合金研发领域的需要。为此,首先对储氢合金活化和循环的实验流程以及控制程序的功能需求进行分析。然后根据分析结果,采用LabVIEW软件实现控制程序的编写。该程序具有断电保持功能,可避免由于长期充放氢操作过程中出现意外停电或者故障而导致重要数据丢失的情况。最后,利用该程序完成了对经过初始活化和1000次吸放氢循环后的LaNi_(4.25)Al_(0.75)合金的等温吸放氢曲线、吸氢动力学曲线和粒度分布的测试,其中重点验证了断电保持功能。实验结果表明:自行编制的LabVIEW程序可以实现预期的功能;随着吸放氢循环次数的增加,LaNi_(4.25)Al_(0.75)合金的最大储氢量减小、吸放氢平台滞后增大、吸氢速率减慢,同时材料粒径显著减小。从整个研究过程可以得出结论:LabVIEW软件功能强大,通过图形化编程可实现储氢合金活化和循环的高效可靠实验,使用效果令人满意,值得在实验仪器开发领域进一步推广应用。

In the experimental processes of hydrogen storage alloy activation and absorption-desorption cycling, the valves of Sieverts apparatus are repeatedly switched, and the cyclic number should be recorded. In order to improve the efficiency of the experimental process and avoid failures caused by all kinds of unexpected reasons, we try to make use of LabVIEW software and the existing Sieverts apparatus hardware in our lab to realize hydrogen storage alloy activation treatment, and test functions of long-term cycle stability and pulverization characteristics, which are necessary to the research and development field of hydrogen storage alloy. For this purpose, the experimental procedure of activation and hydrogenation cycling of hydrogen storage alloy, and the functional requirements of related control program were firstly analyzed. According to the analysis results, new control program based on LabVIEW software were completed. The program has the function of hold during power off, and can avoid the loss of important data caused by unexpected power outage or failure during long-term hydrogen charging-discharging operation. The absorption-desorption pressure composition isotherms, absorption kinetic curves, and particle size distributions of LaNi4.25Alo.75 alloy with initial activation and 1000 charging-discharging cycles were tested by using the control program. In the test process, the function of hold during power off was verified emphatically. The experimental results indicate that the self-made LabVIEW program can achieve the desired functions; with the increase of the cyclic number of hydrogen absorption-desorption, the maximum hydrogen storage capacity was decreased, the plateau hysteresis was increased, the hydrogen absorption rate was decreased, and the material particle size was decreased significantly. From the whole research process, it can be concluded that LabVIEW soft＇ware is powerful; efficient and reliable experiment of activation and hydrogenation cycling of hydrogen storage alloy can be realized by graphical programming; the application effect of LabVIEW software is satisfactory, and the software is worthy of further popularization and application in the experimental instrument development field.