无外部扰动的矿井通风阻力测不准机理研究

The Parameters fluctuate at mine ventilation testing process. To solve this problem, the mechanism of uncertainty for mine ventilation resistance measure with non-interference will be investigatived based on the stochastic theory of turbulence and experimental test. Three-dimensional velocity distribution field of experimental model will be synchronously measured by LDA and PIV, and the influence mechanism of turbulence on the tested parameters and quantitative characterization is systematically analyzed. Two representative roadways include straight roadway and fan drift for main fan are selected, The ensemble average of wind speed is studied between steady homogeneity turbulence without large scale eddy and steady non-omogeneity turbulence with large scale eddy. And expression of mine ventilation resistance based on reynolds-averaged will be reconstructed. Therein it is studied that sampling period convergence criteria and phase averaging method for ergodicity of wind speed data at wind section. According to approximately uniform criterion at the subdomain, finite subdomain division and convergence criteria for single-point reynolds average wind speed at sub-domain will be researched, which lay a theoretical foundation for engineering application of the reynolds averaged testing method in mine ventilation testing process.

针对矿井通风测试过程中仪表的波动性，从矿井风流的湍流随机性理论与实验角度研究矿井通风测不准机理及精确测试方法。本项目采用激光多普勒（LDA）和粒子图像测速仪器（PIV）同步测试实验模型风流三维速度分布场，系统分析湍流对矿井通风测试参数影响机制及其定量表征。选定均直巷道及主通风机风硐两个代表性巷道，分别研究定常均匀无大涡湍流与定常非均匀有大涡湍流的风速系统平均方法，构建基于雷诺平均的矿井通风阻力定律表达式。研究测风断面测点各态遍历的测风数据采样周期收敛准则及相位平均方法。根据子域近似均匀的准则，研究非均匀湍流的有限子域划分及子域单测点风速雷诺平均的近似收敛准则，为基于雷诺平均的矿井风量测试方法的工程应用奠定理论基础。研究条件平均方法及相干结构信号识别方法，为研发检测仪表奠定基础。

风量是矿井通风最重要的基础参数。实时准确的掌握矿井全局的风量分布情况，可以及时察觉系统存在的安全隐患，制定相应的对策措施，从而降低隐患向事故转化的几率。项目从巷道风流自身的湍动特性出发，综合采用理论分析、室内实验、现场试验相结合的方法，对巷道平均风速的单点精准测量方法展开了系列研究，结果发现风速和风压仍然存在剧烈的不规则波动，最大波动幅度达30%，其时间序列服从正态分布并具有规则的统计平均结果。进而提出“测不准”现象是绝对存在而并非单纯由外部扰动决定的，湍流随机脉动是矿井通风参数“测不准”的本质原因，根据实验数据建立了单点时均风速和巷道平均风速的统计测量数学模型，提出单点风速时均化原则为瞬时风速采样时间尺度大于湍流各态遍历时间尺度，以及单点风速时均化过程属于简单随机抽样中的重复抽样，时均风速采样单位数即样本容量，建立了时均风速采样单位数与湍流强度、误差以及置信度之间的关系表达式，提出了速度场结构近似恒定原理，即平均风速变化时，其断面的无量纲速度场结构近似不变，并给出了速度场结构系数的标定步骤，该工作对提高矿井风量在线监测精度具有重要的理论意义和实用价值。