月面钻进采样过程钻具热特性实验研究

发布时间：2018-03-20 09:04

本文选题：月壤　切入点：钻进取样　出处：《哈尔滨工业大学》2014年硕士论文　论文类型：学位论文

【摘要】：月壤钻取是我国月面探测重要任务之一，保证钻进过程的热安全性十分重要。面对月球高真空、高低温等不利环境，本文以钻具热安全性和可靠性为目标，开展钻具钻进过程热特性研究，研究钻具在钻取模拟月壤过程中自身温升以及其向模拟月壤传热情况。首先，本文基于热阻理论，建立了月壤导热模型，分析了月壤导热机理。利用离散元方法仿真验证了基于Hertz理论的粗糙月壤热导与颗粒表面粗糙度的关系。针对粗糙月壤表面形貌具有自相似性特征，本文基于分形理论，根据月壤表面粗糙度，估算了能够合理描述月壤接触轮廓线的分形维数。假设接触变形为弹性变形，借助Weierstrass-Mandelbrot函数绘制出合理的特征参数下月壤接触热导与表面粗糙度的关系曲线。其次，本文基于傅里叶一维导热模型，研制了采用热流计法的真空导热系数测量装置，该装置可测量模拟月壤在真空及高温下的导热系数。利用该装置进行了实验研究，得到了中真空环境及其它真空度下不同温度的模拟月壤导热系数值，分析了温度及真空度对模拟月壤导热系数的影响。再次，，本文基于离散元方法，利用离散元软件对月面钻进采样过程中月壤接触钻具导热情况进行了仿真分析。针对月壤颗粒形态，对月壤进行建模，建立了四种形式的月壤仿真模型。根据月壤性质，设置仿真中合理的物理参数。根据仿真中月壤表现出的传热方式总结了月壤导热后钻头所经区域月壤的温度分布规律，实现对这一过程月壤从钻具导热量的预测。最后，本文开展了钻具热特性试验研究，使用全参数钻取采样试验台，利用采样钻具针对模拟月壤进行了钻进实验，利用光纤光栅传感器实时监测了钻头端面不同位置和侧面轴向不同位置的温升情况。总结了温升随钻具转速和进尺速度变化的变化趋势，获得了钻进过程中钻具的温升特性。
[Abstract]:Lunar soil drilling is one of the important Ren Wuzhi in lunar surface exploration in China, and it is very important to ensure the thermal safety of drilling process. In the face of high vacuum, high and low temperature and other adverse environments, this paper aims at the thermal safety and reliability of drilling tools. The thermal characteristics of drilling tool during drilling were studied to study the temperature rise of drilling tool and its heat transfer to simulated lunar soil during drilling simulation of lunar soil. Firstly, based on the thermal resistance theory, a lunar soil thermal conductivity model is established. The thermal conductivity mechanism of lunar soil is analyzed. The relationship between the thermal conductivity of rough lunar soil based on Hertz theory and the surface roughness of particles is verified by discrete element method. In view of the self-similarity of surface morphology of rough lunar soil, the fractal theory is used in this paper. According to the surface roughness of lunar soil, the fractal dimension which can reasonably describe the contact contour of lunar soil is estimated, and the contact deformation is assumed to be elastic deformation. The relationship between contact thermal conductivity and surface roughness of lunar soil under reasonable characteristic parameters was plotted by Weierstrass-Mandelbrot function. Secondly, based on the Fourier one-dimensional thermal conductivity model, a measuring device for vacuum thermal conductivity is developed, which can be used to measure the thermal conductivity of lunar soil in vacuum and high temperature. The simulated thermal conductivity of lunar soil at different temperatures in the medium vacuum environment and other vacuum conditions was obtained. The effects of temperature and vacuum on the thermal conductivity of the simulated lunar soil were analyzed. Thirdly, based on the discrete element method, the thermal conductivity of lunar soil contact drilling tools during lunar surface drilling sampling is simulated and analyzed by using discrete element software. Four kinds of lunar soil simulation models were established. According to the properties of lunar soil, reasonable physical parameters were set up. According to the heat transfer mode of lunar soil, the temperature distribution of the bit through the lunar soil after heat conduction was summarized. The prediction of the heat conduction of lunar soil from drilling tools is realized. Finally, the thermal characteristics of drilling tools were studied, and the drilling experiments were carried out on the simulated lunar soil by using the full parameter sampling test-bed, and the sample drilling tool was used to simulate the lunar soil. The temperature rise of drill bit at different position and side axial direction is monitored by fiber grating sensor in real time. The variation trend of temperature rise with drilling tool speed and feed speed is summarized, and the temperature rise characteristics of drill tool during drilling are obtained.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P184.5;P634

【相似文献】