Page 106 - 2022年第53卷第6期

Research on velocity distribution and fluctuation law of
bidirectional flow structure of inlet/outlet

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GAO Xueping ，ZHU Hongtao ，LIU Yinzhu ，SUN Bowen ，CHEN Hao 2
（1. State Key Laboratory of Hydraulic Engineering Simulation and Safety，Tianjin University，Tianjin 300072，China；
2. China Water Resources Beifang Investigation，Design and Research，Tianjin 300022，China）
Abstract：The side inlet/outlet of pumped storage power station channel system has complicated flow due
to internal partial flow barriers，etc.，and its internal two-way flow law is not clear. In this paper，a typi⁃
cal inlet/outlet test device is established on the basis of an actual engineering inlet/outlet， and the ad⁃
vanced velocity measuring instrument is used for fine test research. Based on the measurement results of
the Particle image velocimetry technology （PIV），it reveals the two-way flow rules. Under outflow condi⁃
tions，the main flow is formed in the diffusion section of the middle hole and is located in the middle of
the orifice，a low-velocity area is formed at the top of the diffusion section and the adjustment section，
and the main flow in the side hole is not obvious. Under the inflow condition，there is a low-velocity area
at the top of the middle hole and the side hole adjustment section，and the velocity distribution tends to
be uniform after the water flows into the diffusion section. Based on the measurement results of Acoustic
Doppler Velocimetry （ADV），it reveals the law of fluctuating velocity on the section of the trash rack. The
fluctuating velocity of outflow conditions is very large，and can reach 1.8 times of the time-averaged value，
which is different from the general rule of smaller pulsations. Under the inflow condition，the fluctuating ve⁃
locity is very small，which conforms to the general law that the fluctuating velocity fluctuates around the
time-averaged value. The research results will provide a theoretical basis for optimizing the parameters of
the inlet/outlet shape and analyzing the vibration damage of the trash rack.
Keywords：inlet/outlet；PIV；ADV；velocity field；fluctuating velocity

（责任编辑：李福田）

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Meso-scale simulation ofresistivity of ERCC for RCC overwintering layer in alpine-cold region

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LI Mingchao ，DENG Genhua ，YU Lixin ，ZHANG Mengxi ，ZHANG Juntao ，JIA Chao
（1. State Key Laboratory of Hydraulic Engineering Simulation and Safety，Tianjin University，Tianjin 300350，China；
2. Yellow River Engineering Consulting Co.Ltd.，Zhengzhou 450003，China）

Abstract：The insulation of over-winter layer is one of the key points for the temperature control of RCC
dams in alpine region.Compared with traditional external insulation measures，electrically conductive roller-
compacted concrete （ERCC） is a novel functional material，which can solve problems of large temperature
difference between inside and outside RCC through heating. The electro-thermal property of ERCC is the
main characteristic that distinguishes it from conventional concrete，with electrical resistivity being the key
parameter.Firstly，ERCC with different value fraction of coarse aggregate （VFCA） were designed to measure
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the electrical resistivity （ER） at different ages，nd effect of VFCA on ER was obtained.Then，ERCC-2D me⁃
soscopic model was established to analyze the impact of Interfacial Transition Zone （ITZ） on ER of ERCC.
Finally，ERCC-3D meso-numerical models with different VFCA were created by coupling the calculation
method of continuous medium and discontinuous medium，which has been proved by experiment.The result
shows that VFCA significantly increase the ER of ERCC during the period of 28 d，and the ER of ITZ is
quantified，which is 1.5 times of mortar.In order to determine the relationship between ERCC resistivity and
aggregate content，a mathematical model of ERCC resistivity is proposed，combining experiment and meso-
scopic simulation.The change of specimen size and gradation of aggregates has no effect on the resistivity of
ERCC when the VFCA remains constant.
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Keywords：RCC dam；ERCC；ggregate volume fraction；lectrical resistivity；meso-scopic simulation
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（责任编辑：韩 昆）

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