抽水融冰条件下引水渠道水温变化的过程模拟

发布时间：2017-12-28 00:01

本文关键词：抽水融冰条件下引水渠道水温变化的过程模拟　出处：《石河子大学》2017年硕士论文　论文类型：学位论文

【摘要】：抽水融冰技术是解决水电站冻害问题比较经济有效的方法之一,通过注入较高温度的地下水以提升渠水温度,从而防止冰害的产生,且抽取的地下水势能在一定程度上可抵消抽水消耗的电能甚至增加发电量。本文以新疆玛纳斯河流域红山嘴电站抽水融冰引水渠道为研究对象,通过原型观测试验、水槽试验、数值模拟以及理论分析等方法,分析了抽水融冰的关键影响因素,并对抽水融冰条件下引水渠道水温变化的过程进行了研究,为严寒区域的水电站引水渠道冬季冰害的防治提供科学依据与技术支持。(1)以红山嘴电站引水渠道为原型,进行了7口融冰井运行下引水渠道沿程水温变化的观测试验,发现在抽水融冰条件下,渠道沿程水温均在0.5~2.9℃之间,且均比混合前温度增高了0.1~0.3℃,说明了抽水融冰对于渠水的增温效果显著;同时通过水槽试验,对不同渠道引水流量、不同井水流量以及不同注水点位置的渠道沿程水温变化进行了24组水槽试验,结果表明:在注水点处渠道水温明显上升,且水温的最大增幅可达到1.6℃;渠道沿程混合水温明显高于井前渠道水温,且井水流量越大对渠道的增温效果越明显;另外,三口井同时运行时,使渠水产生了累计加温效果,且对渠水增温效果留有富余,导致了过多热量的浪费,因此合理布置注水点位置对实际工程运行尤为重要。(2)以抽水融冰引水渠道实际运行参数为边界条件,基于FLUENT软件平台,建立了三维水温-水动力数学模型,针对单井和多井同时运行情况下引水渠道沿程水温变化过程开展了数值模拟,并将计算结果和原型观测结果进行了对比,保证了模拟结果的可靠性;通过改变井水流量、温度,渠道引水流量、温度以及外界大气温度等条件,分别进行模拟,其结果表明:井水注入后渠道混合水温与井水流量、井水温度以及渠道引水温度均成正比,与渠道引水流量则成反比关系,且混合水温对渠道引水温度和井水流量敏感性较高;同时,多井模拟结果还表明随着较高温度井水的加入,每口井不仅影响下游渠道水温,而且对上游一定距离的渠道水温也有一定影响;根据实际工程运行情况,还模拟了渠道水温为0.1℃时,不同渠道引水流量及大气温度下的沿程水温变化,结果表明:随着渠道引水流量增大和大气温度降低,融冰井的不冻长度逐渐减小;最后,综合分析实际工程的可行性,增加井水注入量或合理布置井群是提高渠道水温,防止渠道冬季运行冰害最直接有效的方法。(3)依据水流热平衡理论,推出了不冻长度计算公式,结合前人原型实测资料对本文不冻长度公式进行验证,保证了不冻长度公式的可靠性;根据计算公式对不同水力、热力、气候条件下的渠道不冻长度进行了计算,结果表明:不冻长度与渠道井水注入量、井水温度、大气温度、日太阳辐射量成正比,与风速、大气饱和差、日降雪量成反比;其中渠道井水注入量、大气温度、风速等对不冻长度影响较为显著。
[Abstract]:Pumping and melting ice technology is one of the most economical and effective method for hydropower station freezing problem, by injecting high temperature water to improve the canal water temperature, to prevent ice damage, and extraction of underground water in a certain extent can offset the pumping power consumption and increase power generation. This paper takes Xinjiang Manasi River Basin Hongshanzui power station pumping and melting ice water channel as the research object, through prototype observation test, flume experiment, numerical simulation and theoretical analysis method, analyzes the key factors influencing the pumping and melting ice, and the process of pumping and melting ice under the condition of diversion channel temperature change are studied, providing control station diversion channel ice disasters in the scientific basis and technical support for hydropower cold region. (1) the diversion channel of Hongshanzui power station as the prototype observation test was carried out in 7 wells under the condition of ice melting water diversion channels along the water temperature change, found in the pumping and melting ice conditions along the channel are in the temperature between 0.5~2.9 DEG C, and were higher than mixed before the temperature of 0.1~0.3 DEG C, the pumping and melting the ice for canal water warming effect; at the same time through flume experiments on different channels and different water flow and water flow of different injection point position along the channel temperature were carried out in 24 groups of flume experiments, results show that increased significantly in the injection point channel temperature, maximum growth rate and the water temperature can reach 1.6 DEG C; the channel along the water temperature was significantly higher than that of the well mixed before the water temperature and water flow channel, the greater the more obvious of the channel of the warming effect; in addition, three wells are running at the same time, the canal water had a cumulative heating effect, and the canal water warming effect left The surplus has caused excessive waste of heat, so it is very important to arrange the location of water injection point to the actual operation of the project. (2) by pumping and melting ice water channel real parameters as boundary conditions, based on the FLUENT software platform to establish the three-dimensional temperature hydrodynamic mathematical model for single well and multi wells while running along the diversion channel under the condition of water temperature variation process in numerical simulation, and the calculation results and the prototype observation results compared to ensure the reliability of the simulation results; by changing the water flow, temperature, flow rate, temperature and water diversion channels outside air temperature conditions were simulated, the results show that the water channel and water temperature after injection of mixed flow, water temperature and water temperature are proportional to the channel, is inversely proportional to the flow of water diversion channel, and mixed water temperature on the temperature and flow of water diversion channels of high sensitivity; at the same time, multi well simulation results also indicate that with the addition of high temperature wells, each well not only influence The downstream channel temperature, but also have a certain impact on the upstream channel temperature range; according to the actual situation of engineering, is also simulated. The channel temperature is 0.1 degrees centigrade, along the water temperature, different channel flow of water diversion and atmospheric temperature. Results show that with the channel diversion flow increases and atmospheric temperature decreases and the melting ice well don't freeze length decreases gradually; finally, a comprehensive analysis of the feasibility of practical engineering, increase the water injection volume or the reasonable arrangement of wells is to improve the channel temperature, to prevent the ice channel running in winter the most direct and effective way. (3) on the basis of water heat balance theory, introduced the calculating formula for freezing length, combined with the previous field data of the free length formula, to ensure the reliability of the free length formula; according to the calculation formula of different hydraulic and thermal and climatic conditions of the channel does not freeze length were calculated. The results show that don't freeze: length and channel water injection rate, water temperature, air temperature, daily solar radiation is proportional to the wind speed and atmospheric saturation deficit, snowfall is inversely proportional to the channel; water injection rate, air temperature, wind speed is more significant for the length of non freezing.
【学位授予单位】：石河子大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV698.26;TV133

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