Experience of Development of Scientific and Methodical Bases of Design of Selective Water Intakes of Hydroelectric Power Stations
Changes of hydrothermal regime of the river in the tail water are one of the negative resuhs of hydrosystem construction in climate zones with contrast seasonal cycles: in summer water is becoming considerably colder,in winter-warmer.The main reason of such phenomenon depends on location of water intakes of HPP turbine disposition at low elevations,where the water temperature is almost constant during a year: not higher than4/5 ℃ and not lower than 3 ℃.As a result,during the winter in tail water of all highhead and medium-head hydroelectric power stations there are multikilometer ice-holes over which in frosty days the dense fog keeps observed,and in the summer low water temperature in the river negatively influences river flora and fauna.It conducts to deterioration of a microclimate of the coastal territory and conditions of the population dwelling.Ecological situation in tail water may be improved by selective intake of water from the surface layer of the reservoir.But in many cases the selective water intake at run-ofriver HPP arrangement is practically unrealizable,because at limited width of water intake front and large discharges of high-head HPP it is impossible to provide necessary unit discharge of water inflow from surface layers of the reservoir,water from surface and deep layers mixes during water intake.To exclude water intake straight in front of the turbine channel,Zhilenkov V.N.proposed principally new approach to solve this task: the selective water intake unit is located on the bank slope,it provides necessary width of the water intake front.To determine the parameters of selective water intake and its arrangement (directflow or bank) we have to know the conditions of formation of hydrothermal regime in the particular reservoir,first of all the position of the thermal wedge (layer of temperature rise) in which water temperature changes abruptly and the conditions to maintain stability of water layers with different density approaching the water intake unit.The authors suggested and validated the application of density Froude number as the criterion of non-mixing of layers.To study the conditions of hydrothermal regime formation in reservoirs,the authors analyzed the information of in-situ survey by 11 deepwater reservoirs of HPP in the Siberia,Far East,North of RF,Eastern Kazakhstan.At that an interesting regularity was found out: for every reservoir,during the whole period of observations,the position of the upper boundary of temperature changes by depth (thermal wedge) was constant for every month.Basing on it,one can conclude that if the depth of the reservoir does not change considerable,its temperature regime remains constant.Averaging the observation data by years there may be obtained the typical diagrams of water temperature distribution by depth for every month for the particular reservoir.These data may also serve as analogue data to design reservoirs for new HPP with selective water intake.
Reservoir hydrothermal regime ecological situation in tail water selective water intakes
V.N.Zhilenkov S.Y.Ladenko
RusHydro, Vedeneev VNIIG, 21, Gzhatskaya Str., St.Petersburg, 195220, Russia
国际会议
The 5th International Yellow River Forum (第五届黄河国际论坛)
郑州
英文
226-233
2012-09-24（万方平台首次上网日期，不代表论文的发表时间）