城市直埋供热管网泄漏精准智能定位是城市供热基础设施安全与节能降碳及智能化运行的关键环节。为提高利用声波法进行直埋热水供热管网泄漏的定位精度，建立DN300管径的大型模化供热实验系统，研究了有无泄漏时，管壁上声波信号随传播距离、温度、压力和流量变化的特性，分析了管道上水泵振动声波的时频特点，然后利用小波阈值法进行信号降噪，得到了供热管道泄漏的特征频段。研究表明，温度对泄漏声波频段影响显著，温度越高声波特征频段分布越大，温度从31 ℃升高到86 ℃后，特征频段从200 ~ 800 Hz扩展至50 ~ 1 500 Hz；传播距离、压力和流量主要影响泄漏信号幅值，对特征频段范围影响较小；水泵声波能量主要集中在3 000 ~ 4 000 Hz处于泄漏信号频段范围之外。利用小波阈值法进行信号降噪，提高定位精度可达0.11%，实现定位距离偏差在±1 m内。

Accurate and intelligent leakage localization of the urban directly buried heating pipe network is the key aspect for the urban heating infrastructure safety, energy-saving and carbon-reducing and intelligence operation. In order to improve the localization accuracy of the direct buried hot water heating pipe network leakage by the acoustic wave method, a DN300 diameter large scaled heating experiment system was established. The effects of acoustic wave propagation distances, temperature, pressure and flow rates on the acoustic wave signal characteristics with and without leakage were studied. The acoustic wave time-frequency characteristics from pipeline pump vibration were analyzed, and then the wavelet threshold method was used for signal noise reduction. It obtained the leakage characteristic frequency band range. The results show that temperature has significant effect on the acoustic frequency band of leakage, and higher temperature contributes to larger acoustic wave frequency band. When the temperature rises from 31 ℃ to 86 ℃, the characteristic frequency band range expand from 200 ~ 800 Hz to 50 ~ 1 500 Hz. The propagation distance, pressure and flow rate mainly affect the amplitude of leakage signal, but they have little effect on the band range. The acoustic energy of the pump is mainly within 3 000 ~4 000 Hz, and it is beyond the range of the leakage characteristic frequency band range. The wavelet threshold method for the signal noise reduction. It could improve the localization accuracy up to 0.11%, along with a localization distance deviation within ± 1 m.