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Water hammer occurs whenever the fluid velocity in vertical lifting pipe systems for deep-sea mining suddenly changes. In this work, the shock wave was proven to play an important role in changing pressures and periods, and mathematical and numerical modeling technology was presented for simulated transient pressure in the abnormal pump operation. As volume concentrations were taken into account of shock wave speed, the experiment results about the pressure-time history, discharge-time history and period for the lifting pipe system showed that: as its concentrations rose up, the maximum transient pressure went down, so did its discharges; when its volume concentrations increased gradually, the period numbers of pressure decay were getting less and less, and the corresponding shock wave speed decreased. These results have highly coincided with simulation results. The conclusions are important to design lifting transporting system to prevent water hammer in order to avoid potentially devastating consequences, such as damage to components and equipment and risks to personnel. 相似文献
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两相流过泵回流试验是模拟水力提升系统紧急停泵情况下垂直管道中颗粒运动状态,紧急停泵时,可能会出现堵管、难于输送等现象。为提高管道水力输送安全性,采用三种不同的模拟结核颗粒(粒径分别为d≤10 mm,d≤20 mm,d≤50 mm),两种不同浓度(CV=5%,CV=8%),在两级泵额定流量Q=420 m3/h条件下进行了过泵回流试验,分析了试验结果,从多个方面总结了堵管原因。认为实际工程中应该严格控制颗粒上限粒径,采用合适的颗粒级配,并对管道定期进行清洗,尽量减少管道的大角度转弯和断面突变。 相似文献
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针对取样于141°48.700 8'E,11°11.698 8'N,深度为8 638 m的马里亚纳海沟海底表层沉积物,考虑该沉积物中的孔隙水为海水,提出一种测定其基本物理性质指标的修正方法,并测定其相关的物理性质指标,最后通过扫描电子显微镜观察其微观结构。研究结果表明:本次取样处的深海海底表层沉积物具有极高的含水率、高孔隙率、低密度、低比重、高饱和度等特性。考虑海水中盐分影响的修正后,该土样的含水率比修正前提高了11.68%,比重比修正前降低了7.66%。该沉积物显微结构以絮凝结构为主,中间夹杂着大量多孔隙的硅藻碎片和生物体的空壳,这使得该沉积物中的孔隙数量增多。研究结果将有助于了解马里亚纳海沟地区的深海沉积环境和历史,为深海集矿车的设计提供参考。 相似文献
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浸没于水中的粗颗粒管道输送系统,由于受到泵、内部两相流及外部流体三者的耦合激励,管道系统振动将对管道输送参数和安全稳定性产生严重影响。为了深入分析水下管道输送系统工作时振动的特性,设计了一套振动测试,对管道系统振动进行了测试,获取管道在不同工况下的时域波形,通过快速傅里叶变换对振动信号进行频谱分析。试验结果表明:随着输送体积浓度增加,X与Y方向的最大振动幅度随着体积浓度增大而增大,但是Z方向的最大振动幅度则是随着体积浓度增加而降低;同一输送浓度情况下,Y方向振动幅度最大,X方向次之,Z方向最小;随着输送浓度提高,流体紊流引起的管道振动加剧。这些结论将为深海采矿管道支撑结构设计和减振提供参考。 相似文献
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