飞艇螺旋桨推进系统动态特性验证方法研究

Research on Dynamic Performance Verification Method for Propulsion System of Airship

临近空间飞艇螺旋桨推进系统运行高度在20 km的高空,由于地面的空气密度约为该高度的14倍,因此在地面由于扭矩超限,推进系统并不能转到高空的额定转速,造成推进系统的动态特性在地面无法准确测试;另一方面,动态特性是反映推进系统整体性能的重要指标,也是研究工作中最值得关注的核心问题。目前主要有动态数值仿真、地面负载模拟器和全尺寸地面车载试验3种动态特性验证方法,这3种方法形成了一种梯次递进的验证途径,使验证结果逐步接近真实系统。全尺寸地面车载基本是推进系统在地面一定转速范围内的局部验证,由于该系统复杂性和篇幅所限,需要专题讨论,文章只针对前2种方法展开初步研究。根据电机和螺旋桨之间转速、力矩平衡关系在Matlab/Simulink中建立推进系统动态仿真模型,并进行某一实例仿真验证。通过在待测电机输出轴上联接负载模拟器,对推进系统分别进行加减速特性和抗突风特性测试,并进行半物理仿真分析。结果表明,文中基于动态数值仿真和地面负载模拟器的方法,在研究和评价系统动态特性时,有重要的参考价值。

Near space airship running at, because the air density of the ground is about fourteen times that of 20 km altitude, because of torque overrun, on the ground, propulsion system can＇t go to rated speed of the high alti- tude, the dynamic characteristics of propulsion system can＇t accurate measurement; On the other hand, the dynamic characteristics is an important index of propulsion system performance, is also the most notable problems in the study. There are three kinds of validation methods for propulsion system dynamic characteristics： the dynamic numerical simulation, the load simulator validation method and the full-size truck-mounted testing system. This three methods form a kind of arrangement in validation of progressive way, it makes the results of the validation gradually close to the real system. It is the full-size truck-mounted testing that propulsion system is partial validated of the ground speed range, due to the limitation of the system complexity and length in this paper, it requires spe- cial topic and this paper focus the others. According to rotational speed and torque balance between motor and pro- peller propulsion system, simulation model is built in Matlab/Simulink, and some simulation case is validated; then joining the load simulator to the motor output shaft under test, and testing the propulsion system property for deceleration or a sudden wind resistance, Semi physical simulation analysis was carried on. The results show that numerical simulation and full-size truck-mounted testing system have important reference value, in the research and evaluation of the system dynamic characteristics.