Effect of Cooling Water Flow Path on the Flow and Heat Transfer in a 660 MW Power Plant Condenser

The effect of the cooling water flow path on the flow and heat transfer in a double tube-pass condenser for a 660 MW power plant unit was numerically investigated based on a porous medium model. The results were used to analyze the streamline, velocity, air mass fraction and heat transfer coefficient distributions. The simulations indicate that the cooling water flow path is important in large condensers. For the original tube arrangement, the heat transfer with the lower-upper cooling water flow path is better than that with the upper-lower cooling water flow path. The reason is that the steam cannot flow into the internal of upper tube bundle and the air fractions are higher in the upper tube bundle with the upper-lower cooling water flow path. An improvement tube arrangement was developed for the upper-lower cooling water flow path which reduced the back pressure by 0.47 kPa compared to the original scheme. Thus, the results show that the tube arrangements should differ for different cooling water flow paths and the condenser heat transfer can be improved for the upper-lower cooling water flow path by modifying the tube arrangement.

三峡电站日调节对下游河道水面比降的影响

根据水电站日调节波的特性,运用一维恒定流和非恒定流泥沙数学模型,分别计算了河道涨落水过程的水面线.在此基础上,用恒定流泥沙数学模型计算了三峡水库建库前后,其下游宜昌～沙市河段的水面线.并结合三峡和葛洲坝两电站联合运行的实际情况,研究了调节方案对三峡水库下游河道水面比降的影响.

大型输水渠道中过水建筑物的新处理方法

大型调水工程渠道设计中有大量的过水建筑物,给开发非恒定模拟计算软件带来了一定的困难。为此,提出采用虚拟渠道等效糙率的方法,用来模拟各输水建筑物对渠道中的水位和流量的影响。开发了非恒定流计算软件,成功用于南水北调中线工程总干渠渠道的非恒定流过程的模拟计算。

福建省地表径流N、P流失系数的测算

通过对福建省12个地表径流监测点径流水中氮磷含量的分析,得出了福建省地表径流的N、P流失系数。结果表明:我省总氮流失系数为0.414%-7.862%,总磷流失系数为0.032%-1.314%。

矿井水害的防治

水害给国家和人民生命财产造成的损失是巨大的。所以水害的威胁就成了煤矿生产的重大灾害之一,因此,必须提高警惕,做好煤矿防治水工作。

考虑旁侧入流水面曲线一维水力学模型及应用

为得到某防洪工程的水面曲线,依托新疆某地区拟建堤防工程,综合运用水文学、数学、水力学知识,借助于计算机建立了考虑旁侧入流计算水面曲线一维水力学模型,结果显示:50年一遇水面曲线计算推求结果低于设计堤顶高程约2~3m。考虑旁侧入流一维水力学模型水面曲线计算结果是更加合理的,可为同类其他堤防工程设计和安全运行提供借鉴。