长距离供水工程空气罐调压塔联合防护水锤

结合某实际供水工程并基于特征线法,建立了包含水泵、管道及水锤防护措施的全系统过渡过程数学模型,模拟了停泵工况下系统的压力变化过程.通过计算发现,由于局部高点内水压力较小,为了保证沿线不出现负压,采用常规空气罐方案时,空气罐体积达到530.00 m³.针对常规空气罐方案体积过大的问题,提出了空气罐双向调压塔联合防护方案和空气罐单向调压塔联合防护方案,并对比分析了2种联合防护方案的效果.结果表明2种联合防护方案都能较大幅度地降低空气罐的体积.空气罐双向调压塔联合防护方案下,空气罐体积降至40.27 m³,但双向调压塔高度受测压管水头控制,水泵扬程较高时导致其高度较高,双向调压塔高达到27.00 m;单向调压塔的高度不受测压管水头限制,联合防护方案下空气罐体积为43.83 m³,但为了保证局部高点不出现负压,需增加沿线单向塔的数量.

Water hammer protection in long-distance water supply project with combined air vessel and surge tanks

Based on the method of characteristics(MOC), the mathematical model of an integrated system including the pump, pipeline, and water hammer protective measures is established in terms of a practical water supply project, and the transient pressure variation process in the system is simulated during a pump sudden stopping period. Based on simulations a low pressure exists at the local high elevation site. To avoid a negative pressure in the pipeline if an orderinary air vessel is involved in the system, then its volumme can be as large as 530.00 m³. To solve this problem, two methods, namlely, air vessel-two-way-surge tank and air vessel-one-way-surge tank, are proposed, their protective effectiveness is analyzed and compared. The results show that the volume of air vessel can be significantly reduced by two protective methods proposed. For the air vessel-two-way-surge tank method, the volume of air vessel has been reduced to 40.27 m³, however, its height reaches as high as 27.00 m, because the tank height is controlled not only by the piezometric head but also by the pump head. For the air vessel-one-way-surge tank method, the tank height is not limited by the piezometric head, and the volume of air vessel is reduced to 43.83 m³. Unforatunantely, more tanks are needed to ensure no negative pressure in the pipeline.