初始释放瓦斯膨胀能测定装置中渐缩形喷口的流量特性研究

发布时间：2018-04-22 12:49

本文选题：初始释放瓦斯膨胀能 + 测定装置　；参考：《中国矿业大学》2015年硕士论文

【摘要】：初始释放瓦斯膨胀能预测法为现场定量预测煤层的突出危险性提供了一套全新的方法,正确选择渐缩形喷口有效截面积S值的测定方法对测定结果的精确度有着重要影响。原先采用气容放气法测定S值只适用于气流通过渐缩形喷口处于音速阶段时初始释放瓦斯膨胀能的计算,而气流通过渐缩形喷口的过程分为音速与亚音速两个阶段,但以往却将两个阶段的S值做同一值而论。针对这一问题,本文提出一种测定S值的新方法,其实质就是通过测定渐缩形喷口的流量特性相关参数去间接求取S值,弥补了原先测定方法的不足,进而有利于实现初始释放瓦斯膨胀能测定结果的精确化。本文的主要研究工作从以下三个方面着手:首先分析研究渐缩形喷口的流量特性及其测试方法,包括影响流量特性的因素,表示流量特性的几种常用方法,以及各个参数的测试方法;然后设计一套测试系统,给出详细的设计过程;最后利用设计好的测试系统对渐缩形喷口流量特性的相关参数进行测定,利用这些测定的参数求取有效截面积S值,同时采用原先的气容放气法测定S值,并对两种方法测定得到的S值进行比较分析。通过以上的研究工作,得到以下成果:(1)提出了一种测定渐缩形喷口有效截面积S值的新方法,通过测定渐缩形喷口的流量特性各个参数分别得到了音速与亚音速两个阶段的S值;(2)设计了一套基于国际标准测试方法并结合计算机数据采集的测试系统,能够准确测定渐缩形喷口的流量特性各个参数;(3)测定了渐缩形喷口的临界压力比b值为0.284,并根据b值准确划分了气流通过渐缩形喷口时的音速与亚音速阶段;(4)得到了渐缩形喷口的有效截面积S值在音速与亚音速阶段分别为2.87mm2与2.33mm2,用原先方法测定了S值为2.70mm2,并将两种测定方法进行了比较分析,突出新方法适用性更强的优点。
[Abstract]:The prediction method of initial gas release expansion energy provides a new method for quantitative prediction of coal seam outburst risk. The correct selection of effective cross section S value of tapered nozzle has an important influence on the accuracy of the measurement results. Previously, the measurement of S value by gas volumetric discharge method was only applicable to the calculation of the initial gas expansion energy when the air flow passed through the tapered nozzle at the sonic stage, while the gas flow passing through the tapered nozzle was divided into two stages: sonic and subsonic. But in the past, the S value of the two stages was treated as the same value. In order to solve this problem, a new method for measuring S value is put forward in this paper. The essence of the method is to obtain the S value indirectly by measuring the parameters related to the flow characteristics of the tapered nozzle, which makes up for the deficiency of the original measurement method. Thus, it is helpful to realize the accuracy of the measurement results of the initial gas release expansion energy. The main research work of this paper is as follows: firstly, the flow characteristics of the tapered nozzle and its testing methods are analyzed, including the factors affecting the flow characteristics, and several common methods to express the flow characteristics. And the test method of each parameter; then design a set of test system, give the detailed design process; finally, use the designed test system to measure the relevant parameters of the flow characteristic of the tapered nozzle, The effective cross sectional area S value was obtained by using these parameters, and S value was measured by the original gas volumetric discharge method. The S values obtained by the two methods were compared and analyzed. Through the above research work, the following results are obtained: 1) A new method for determining the effective cross section area S of tapered nozzle is proposed. By measuring the flow characteristics of tapered nozzle, the S value of sonic and subsonic stages is obtained, respectively. A test system based on international standard testing method and computer data acquisition is designed. The critical pressure ratio b of the tapered nozzle is determined to be 0.284, and the sonic and subsonic stages of airflow passing through the tapered nozzle are accurately divided according to the b value. When the effective cross sectional area S of the tapered nozzle is 2.87mm2 and 2.33 mm 2 at the sonic and subsonic stages, the S value of the original method is 2.70 mm 2, and the two methods are compared and analyzed. The advantages of more applicability of the new method are highlighted.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD713.2

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