基于激光测距技术的灌浆流量检测方法测量精度研究

Research on measuring accuracy of grouting flow detection method based on laser ranging technology

针对目前灌浆过程中使用电磁流量计测量低流速状态下浆液流量精度较低的问题,提出一种基于激光测距技术的灌浆流量实时检测方法。首先,通过理论分析,推导浆液流量计算公式,然后,利用Fluent软件对该检测方法的测量精度进行研究,并采用正交试验设计法研究浆液水灰比、搅拌桨转速、排浆速度这3个设计参数对该流量检测方法测量精度的影响。研究结果表明:采用测量液位高度得到低排浆速度下浆液实时流量的检测方法具有一定的可行性,将搅浆桶内液面高度下降4 mm所需时间作为单位时间计算浆液流量,所测流量相对误差在6%以内,且在0.013 m/s低排浆速度下,该检测方法测量精度较电磁流量计的测量精度有大幅度提升;排浆速度是影响流量测量精度的最直接因素,在低排浆速度下,排浆管内浆液易产生回流现象,进而加剧浆液液面的不稳定程度,导致流量测量误差偏大。

Aiming at the problem of low accuracy of grout flow measured by electromagnetic flowmeter in grouting process,a real-time slurry flow detection method based on laser ranging technology was proposed.Firstly,through theoretical analysis,the slurry flow calculation formula was derived.Then,Fluent software was used to study the measurement accuracy of the detection method,and orthogonal experimental design method was used to study the influence of three design parameters,i.e.,slurry water-cement ratio,propeller speed and slurry discharge speed on the measurement accuracy of the flow detection method.The results show that it is feasible to measure the liquid level height to get the real-time slurry flow at low discharge speed.The relative error of measured flow is within 6% by taking the time required for the liquid level height to drop by 4 mm in the slurry barrel as unit time,and the measurement accuracy of this detection method is greatly improved compared with that of electromagnetic flowmeter at 0.013 m/s low discharge speed.The slurry discharge speed is the most direct factor affecting the accuracy of flow measurement.At low discharge speed,the slurry at the discharge pipe is easy to produce reflux phenomenon,which furtherly aggravates the instability of the grout level,resulting in large error of flow measurement.