基于超声波时差法的矿用换能器安装位置研究

Installation positions of mine ultrasonic transducers based on ultrasonic time difference method

  • 摘要: 针对现有超声波时差法测风技术因换能器安装位置未能动态适配不同巷道截面而导致测量精度受限的问题,基于不同巷道截面(矩形、梯形、拱形等)的2个超声波换能器安装位置进行研究。通过Fluent数值模拟与井下人工测量,验证了存在一条平行于巷道底板的平均风速线。在此基础上,融合湍流应力分解理论与普朗特混合长理论,并引入修正系数,推导出不同巷道截面处的平均风速线距巷道底板高度的函数。结合测速区间的确定,完成对2个超声波换能器安装位置的研究。模拟及现场测试结果表明:① 相较于传统换能器固定高度安装方法,基于所提换能器安装位置确定方法得出的测量精度在相同工况下表现更为优异。② 安装的换能器在矩形巷道中表现最佳,其测风结果与人工测量的相对误差为4.486%;在拱形巷道中次之,相对误差为4.935%;在梯形巷道中最差,相对误差为5.579%。③ 以标准差作为标准,安装的超声波换能器测风结果标准差均小于人工测量结果标准差,表明其在井下环境的数据采集更稳定。

     

    Abstract: To address the limitation in measurement accuracy of existing ultrasonic time difference anemometry caused by the inability of transducer installation positions to dynamically adapt to different roadway cross-sections, this study investigated two ultrasonic transducer installation positions for different roadway cross-sections (such as rectangle, trapezoid, arch, et al). Fluent numerical simulations and underground manual measurements were conducted to verify the existence of an average wind velocity line parallel to the roadway floor. On this basis, by combining turbulent stress decomposition theory with Prandtl's mixing length theory and introducing a modified coefficient, the height function of the average wind speed line from the roadway floor for different roadway sections was derived. Together with the determination of the velocity measurement interval, the installation positions of the two ultrasonic transducers were determined. Simulation and field test results showed that: ① compared with the traditional fixed-height transducer installation method, the proposed transducer installation position determination method achieved higher measurement accuracy under the same operating conditions. ② The installed transducers performed best in rectangular roadways, with a relative error of 4.486% compared with manual measurements, followed by arched roadways with a relative error of 4.935%, while trapezoidal roadways showed the largest relative error of 5.579%. ③ Using standard deviation as the evaluation criterion rsingstandard deviation as the evaluation criterion, the standard deviation of wind velocity measurements obtained by the installed ultrasonic transducers was smaller than that of manual measurements, indicating more stable data acquisition in underground environments.

     

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