An in situ measurement method of sound speed in liquid for acoustic emission testing of cylindrical storage tank was proposed,and some factors influencing the precision were also analyzed by an experiment.The approach was based on the normal acoustic emission testing scheme,and a simulation source was used to stimulate vibrations which could be detected by some sensors,finally the sound speed was conducted by computing the transportation time of the first wave directly arriving at through liquid.In the following experiment, three simulation signals,namely break pencil,30 kHz and 60 kHz,were compared to find that the pulse of high frequency is the best choice on locating the first wave directly arriving at through liquid.The experiment revealed that the envelop-tangent method was superior to the other two methods (the threshold method and the cross-correlation method)in computing the time difference of arrival waves.The study also showed that the accuracy of this in situ measurement method was very high.%提出了一种现场测量圆柱形储液罐液体声速的方法，并通过试验分析了影响测量精度的有关因素。液体声速测量采用常规的声发射检测布置方案，激发模拟声源产生振动，然后获取液体直达波的传播时间从而计算出声速。对比了断铅、30 kHz和60 kHz的三种模拟信号，结果表明高频成分为主的声源更有利于定位液体直达波。对阈值法、相关法和包络切线法三种波达时差计算方法进行了比较，结果表明包络切线法更有效。试验数据表明，提出的现场测速方法具有较高的精度。
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