王毓国,张爱军,靳芮掞,等. 长距离输水渠道电热防冰冻技术现场试验及功率计算[J]. 农业工程学报,2023,39(12):114-122. DOI: 10.11975/j.issn.1002-6819.202302018
    引用本文: 王毓国,张爱军,靳芮掞,等. 长距离输水渠道电热防冰冻技术现场试验及功率计算[J]. 农业工程学报,2023,39(12):114-122. DOI: 10.11975/j.issn.1002-6819.202302018
    WANG Yuguo, ZHANG Aijun, JIN Ruishan, et al. Field test and heating power calculation of the electric heating technology to reduce icing for long-distance water canal operation[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2023, 39(12): 114-122. DOI: 10.11975/j.issn.1002-6819.202302018
    Citation: WANG Yuguo, ZHANG Aijun, JIN Ruishan, et al. Field test and heating power calculation of the electric heating technology to reduce icing for long-distance water canal operation[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2023, 39(12): 114-122. DOI: 10.11975/j.issn.1002-6819.202302018

    长距离输水渠道电热防冰冻技术现场试验及功率计算

    Field test and heating power calculation of the electric heating technology to reduce icing for long-distance water canal operation

    • 摘要: 因冬季水面冻结,寒区渠道的停水期最长可达半年,对渠道输水效益的发挥和当地经济发展影响巨大。为延长寒区渠道冬季的输水时长,研究团队前期提出了长距离输水渠道电热防冰冻技术,并开展了室内模型试验。在前期模型试验的基础上,研发了3种铝制传热装置,选取集肤发热电缆,设计了电源控制和加热功率控制电路,在新疆635工程50 km处的退水渠上建立了现场试验段,进行了历时一个冬季的现场试验观测。同时,理论推导了保持加热区渠水不结冰的加热功率计算式。现场试验结果表明,所设计的电加热系统可以保证渠道冬季输水时不形成岸冰,有效延长渠道冬季运行时间;所设计的传热板传热效率较高,环境温度为−20 ℃时,维持加热装置附近5 cm范围内的水体不结冰,所需要的加热功率为120 W/m;环境温度为−15 ℃时其所需的加热功率为84 W/m,与保障输油工程冬季正常运行的加热功率相比,装置能耗较低。推导的不同环境温度下加热功率的计算式,可以准确计算保障渠道冬季运行的加热功率,为加热电路容量设计提供理论基础。

       

      Abstract: The canals can always shut down nearly for half year in cold regions, due to the freezing of water. It is a serious threat to the efficiency of canal water delivery and economic development. A key position can be found in the formation of ice cover, according to the canal water frozen and the development of ice cover. And the slope of the canal is one of these key positions. In this study, an electric heating technology was proposed to reduce the icing for the better extent of the canal operation time in winter. The skin effect heat cables (a heat cable with high heating efficiency, reduced circuit voltage, and single power supply for long-distance heating) were installed at the canal slope near the water surface along the canal. Three forms of heat transfer device were also designed for the application requirements. This electric heating technology was tested in the field at the ambient temperature of 0.7 to −23.5 ℃. The heating power was calculated for the canal's winter operation, and then compared with the electric heating in oil pipeline project. The field test results show that this electric heating technology was fully met the winter operation of the long-distance canal. The heat transfer device effectively extended the influence of the heat sources on the canal in winter. This electric heating technology effectively raises the surface water temperature compared to the no-heating situation. The canal water within 5 cm around the heating devices remained free from the freeze under the heating power of 120 W/m at the ambient temperature of −20 ℃, or under the heating power of 84 W/m at the ambient temperature of −15 ℃. Only the heating power of 56 W/m was needed to maintain the positive temperature of heating devices at an ambient temperature of −15 ℃, while the heating power of 30 W/m was needed to maintain a positive temperature of heating devices at the ambient temperature of −10 ℃. The heating power was calculated at different ambient temperatures of this electric heating technology, in order to reduce the icing for the long-distance water canal operation. The modified formula provided the theoretical basis for the electric circuit design. The running heating power demonstrated that the heating power of 226 W/m was selected for the canal operation at −39 ℃, which was the lowest temperature in this local area. The power consumption of this device was about 10.8 (kW·h)/(m·d). Only the heating power of 46 W/m was for the canal operation at −8 ℃, which was the average temperature of this local area. The power consumption of this device was about 2.2 (kW·h)/(m·d) at this moment. A smaller energy consumption which shows a high feasibility was achieved in this electric heating technology for the canal winter operation at the same ambient temperature, compared with the electric heating in the oil pipeline project. Therefore, this electric heating technology can be expected to reduce the icing for the long-distance water canal operation in winter. The finding can provide a high-value promotion in the canal of a hydropower station in winter.

       

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