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1.
Model studies of the hydraulic operating conditions of an eddy tunnel outlet with an inclined shaft showed that:
–  for regimes without delivery of air into the flow core with swirler parameterA=1.1 and with delivery of air for all values ofA, submergence of the outlet section of the conduit in the lower pool noticeably affects the size of the core and promotes the formation of a hydraulic jump zone along the tunnel;
–  insignificant (in value) submergences of the exit section of the tunnel have little effect on the discharge capacity of the outlet (their differences is Δ=1.4% forA=0.6, Δ=2.71% forA=1.1, and submergence even increases the discharge of the outlet Δ=0.8% forA=0.83).
–  delivery of air into the flow core has little effect on the discharge capacity of the structure, with the exception of the layout with a swirler withA=0.6 (Δ=4.31% forA=0.6, Δ=0.5%, and Δ=0.9% forA=1.1);
–  considerable vacuums are observed for regimes without air in the flow core, the absolute values of which with increase ofA drop intensely from Hfc=−4.5 m to Hfc=−0.3m;
–  delivery of air into the flow core markedly reduces the vacuums in it and their values are close to zero;
–  with increase of swirler parameterA the area occupied by the flow at the end of the tunnel decreases;
–  regimes without delivery of air into the flow core are the most favorable with respect to the conditions of the pressure distribution on the conduit walls;
–  submergence on the downstream side does not lead to an increase of pressure on the conduit walls if the vacuum in the flow core increases simultaneously with this.
Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 11, pp. 41–44, November, 1997.  相似文献   

2.
Conclusions  
1.  Operation of the structures of the Votkinsk hydrostation occurs under condition different from those proposed in the design: there is no backwater from the reservoir of the Lower Kama hydrostation, as a consequence of transformation of the Kama channel the lower pool levels are 1 m below the design levels.
2.  As the experience of operating the Votkinsk hydrostation with considerable daily variations of the load and, accordingly, with considerable fluctuations of the lower pool level shows, the unprotected stretches in the lower pool in the zone of variable levels are subjected to erosion. They have to be protected during operation. The earlier works on revetting the eroded stretches are performed, the smaller the expenditures they require.
3.  At hydrostations operating under conditions analogous to those of the Votkinsk hydrostation it is necessary to conduct hydraulic studies in the lower pool and to measure the flow velocities for the purpose of eliminating erosion as well as for the correct selection of the variant of revetting the downstream stretches.
4.  For further safe operation of the Votkinsk hydrostation it is necessary to carry out in 1996–1998 revetting of the downstream slope of earth dam No. 1 and works on preventing scour behind the toe wall of the apron of the hydrostation in accordance with the design of Lengidroproekt.
Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 2, pp. 33–36, February, 1997.  相似文献   

3.
1.  An intake structure with a closed flow having a vertical axis of rotation contributes to the development of a favorable kinematic structure in the channel, which makes it possible to minimize scouring beyond the structure.
2.  Excedence of the near-bottom average and maximum velocities above the average velocities in the channel comes about atl3.3hc downstream from the axis of the intake.
3.  The magnitude of the ratio of the maximum 1st-percentile and average 50th-percentile flow velocities (v1%/v50%), which characterizes the velocity pulsation, attains values for the undisturbed flow in the near-bottom region at a distancel4.1hc.
4.  Complete equalization of the plan diagram of velocities is noted at a distance (4.9–7.8)hc from the axis of the intake structure.
Translated from Gidrotechnicheskoe Stroitel'stvo, No. 4, pp. 17–19, April, 1991.  相似文献   

4.
1.  The energy-storage hydroelectric station (ESHES) can provide a 1.5–2-fold increase in peak capacity with a simultaneous threefold decrease in daily fluctuations of the water level in the lower pool.
2.  A decrease in the length of the concrete structures located in the river channel (especially the length) of the powerhouse) reduces the consumption of concrete for the ESHES in comparison with the HES, which compensates for the cost of constructing the additional structures of the ESHES.
3.  Unlike the HES, the ESHES operates in a sharp-peak regime and also during passage of flood waters.
4.  Contrarotating pump-turbines are best suited for an ESHES because of various combinations of heads on its turbine and pump parts.
5.  With increase in the speed of multistage hydraulic machines their placement depth decreases and the cost of the powerhouse is reduced.
  相似文献   

5.
1.  Consideration of the three-dimensional character of seepage flow in the region of shore abutments in rock-and-earth-fill dams exerts a major influence on the basic seepage parameters required for the design of the core profile, the gradation of soils in reciprocal filters of transitional layers, etc.
2.  The three-dimensional character of the flow exerts the most significant influence on the value of Jdis, especially along the line of contact between the lower face of the core and the shore slope Jdis.S. In that case, the steeper the slope, the greater amount the values of the discharge gradients are lowered.
3.  With three-dimensional seepage, increased Jdis values arise in the core primarily along the water line of the lower pool and the line of contact between the lower face and horizontal underflooded sections; it is precisely in this connection that special protection should be specified.
4.  In evaluating the seepage resistance of the core soil for contact overflow, it is recommended to use the component of the gradient Jdis normal to the plane of the downstream face Jn.n as the computed discharge pressure gradient.
5.  Computational relationships for determination of parameters of three-dimensional seepage, which are required for engineering calculations of the cores of rock-and-earth-fill dams are proposed in the paper. Computational methods based on plane seepage yield significant errors in a number of cases, and should therefore be used with certain caution, even in preliminary stages of design.
Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 7, pp. 24–29, July, 1993.  相似文献   

6.
1.  The morphometric method of estimating the geometry of stable canal channels, as based on a deeper physical nature and using the fluvial process theory principle, has become most popular in solving the problem of designing canals in alluvial soil. It can be considered that sufficiently reliable relations have presently been obtained which can be used in practice with consideration of the particular canal operating conditions.
2.  More detailed investigations of the separate consideration of the transport of bottom and suspended sediments on stability for providing channel stability of canals when vvne are needed for refining the morphometric relations.
3.  It is necessary to continue investigations of the effect of the sediment concentration of a flow on the velocity structure of the flow and noneroding velocity.
4.  It is necessary to consider as one of the most important problems of open-channel hydraulics the activation of experimental and theoretical investigations of the three-dimensional turbulent structure of a flow for the purpose of estimating the distributon of local velocities in the flow cross section as a function of the size of the channel and roughness of its walls.
5.  For dynamically stable canal channels investigations are needed for estimating the roughness coefficient as a function of the channel size , shape, sediment concentration of the flow, and bed-load transport.
6.  It is necessary to prepare the relevant materials for compiling standard data on the design of dynamically stable canals.
Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 3, pp. 37–42, March, 1991.  相似文献   

7.
Conclusions  
1.  Clearing small silted rivers in the Volgograd and Rostov regions by means of floating dredges confirms the expediency of these works for irrigating farmlands, pisciculture, and improving ecology.
2.  Works on clearing and dredging small rivers have their own characteristics, which should be taken into account when working out the technical documents and performing the works.
3.  Simultaneously with channel clearing, comprehensive measures should be taken to prevent erosion of the banks and pollution of the river by wastewaters.
4.  The project documents should be drawn up with consideration of a multipurpose approach to the use of the river’s water resources.
Translated from Gidrotekhnicheskoe Stroitel’stvo, No. 6, pp. 41–44, June, 1998.  相似文献   

8.
1.  For short revetmentsl r/l j<1.5, the=" vertical=" component=" of=" the=" fluctuation=" instantaneous=" bottom=" velocity=" has=" a=" considerable=" effect=" on=" the=" depth=" of=" the=" scour=" pocket.=">
2.  The results of investigating the velocity structure of the flow obtained on erodible models with a length of the revetment less than 1.5l j and limited time of the experiment do not reflect the actual kinematics of the flow in the pocket in the case of completely stabilized scouring.
3.  For the velocity-squared region of resistance of the channel and revetment lengths less than 1.5l j, as well as for the transition region of resistance and revetment length less than 2l j, it is necessary to carry out artificial lowering of the bottom of the lower pool to obtain the kinematic characteristics of the flow corresponding to stabilized scouring.
4.  For a revetment length equal to or greater than 2l j, the results of investigating the kinematic structure of the flow obtained on the model can be transferred to the prototype without correction.
Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 12, pp. 42–45, December, 1991.  相似文献   

9.
Conclusions  
1.  In the upper reservoir of the Zagorsk PSS there are standing waves of a complex frequency spectrum having a virtually undamped character.
2.  The excess of the level of the crest of the upper reservoir embankment of the PSS should be selected with consideration of not only waves caused by meteorological factors but also the presence of standing waves.
3.  The standard systems of measuring the upper pool level of the PSS should provide for averaging the measurements.
4.  To eliminate nonproductive water losses through leaks of the close gate apparatus of the PSS units and increased power losses in the SC regime, it is advisable to provide for the installation of preturbine gates at newly planned PSSs.
Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 10, pp. 39–42, October, 1999.  相似文献   

10.
Conclusions  
1.  When searching for the optimal steel percent needed for providing the bearing capacity of a specimen, it is necessary to take into account the factor of reinforcement arrangement in the soil.
2.  It is seen from the dependences γcd*=f(ζ) obtained for specimens with various steel percent that with an increase of the factor of reinforcement arrangement in soil ζ the work conditions factor decreases, which makes it possible to introduce the given factor in formula (1) for determining γcd*.
3.  The lining of the model must be regarded as an element increasing the bearing capacity of the reinforced earth model.
4.  In the case of a discontinuous and continuous lining the bearing capacity of the models (with the same steel percent) is higher than that of models with a flexible lining.
Translated from Gidrotekhnicheskoe Stroitel’stvo, No. 3, pp. 19–21, March, 1998  相似文献   

11.
Conclusions  
1.  Theoretical investigations and bench tests on a pump model made it possible to obtain the setting geometry that ensures extremely good power characteristics for pumps having large setting flow areas.
2.  It is recommended to use wear-resistant white chromium-manganese cast iron for components in the setting of the GrT-4000/71 soil pump, which is intended for the transfer of sandy-gravelly soils with a lump size no greater than 60 mm.
3.  Use of a dual-cup rubber shaft seal is recommended to improve the operational reliability of the pump.
4.  To extend the longevity and improve the reliability of the drive of the soil pump, it is proposed to use a bearing with a set of spring that lower the axial forces on the bearing.
Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 2, pp. 31–37, February, 1999.  相似文献   

12.
1.  A comparison of laboratory and on-site data on a determination of the maximum range of oscillations at the end of a direct hydraulic jump when waves enter it from a chute with the results of calculations by theoretical formulas (1), (2), and (3) confirms the applicability of one of these formulas (2) for superrapid flow and flow transitional from superrapid to rapid.
2.  The stilling basin generates secondary waves, reaching half of the depth of the basin d with respect to its height. With submergence of the basin from the lower pool, the range of variations of the level increases additionally by 2.0–2.5 times.
3.  On the apron behind the stilling basin, the drop of waves is insignificant, since the wave transformation coefficient at distance (40–90)hn, where hn is the natural depth, remains equal to .
4.  The periods and lengths of the waves transformed in the stilling basin decrease with increase of discharge and Froude number Fr0 and approach in value the wave periods.
5.  Formulas (6) and (10) were obtained for calculating the maximum amplitude of oscillations of the free surface and maximum depth at the crest of oblique waves on the narrowing sections of the wave chutes and they were checked experimentally, which proved the applicability of these formulas for calculating a nonstationary oblique hydraulic jump.
6.  The proposed empirical formulas (12)–(17) can be recommended for an approximate evaluation of the parameters of the largest first waves on the narrowing stretch.
7.  Under these conditions, the use of a stilling basin as an energy dissipator of a superrapid flow is not rational, since not dissipation but generation of secondary waves is observed in it. When designing narrowing sections of chutes, it is necessary to take into account an increase of depth of the oblique jump with passage of roll waves.  相似文献   

13.
Conclusions  
1.  The proposed calculation method permits mathematical modeling of the process of filling and emptying the lock chamber with simultaneous operation of several thrift basins and pool, which is especially important for converting existing locks of the given type to a new operating regime.
2.  Using the proposed method, one can select the design and dimensions of elements of the lock supply system without resorting to physical modeling.
Translated from Gidrotekhnicheskoe Stroitel’stv, No. 6, pp. 7–10, June, 1998.  相似文献   

14.
Conclusions  
1.  The concrete of the Vilyui III hydrostation is characterized by a strength exceeding the grade and a high modulus of elasticity, and for the structural members of the main structures by a long stay during construction at low temperatures —to minus 15–35°C.
2.  The strength and deformation characteristics determined by tests of specimens and cores from mature concrete (up to 4.6 years) of grades M250 W8 F100, M300 W10 F100, and M400 W12 F400 were: cube Rcub and prism Rpr strengths, respectively, 40–57 and 20–45 MPa; initial modulus of elasticity Ec=(4–4.3)·104 MPa and Poisson's ratiov=0.127; for M250 and M300 Rpr/Rcub=0.65 and for M400, 0.8.
3.  The initial modulus of elasticity of the on-site concrete M250 at an age of 400–500 days at positive temperatures was Ec=4.6·104 MPa. Freezing of concrete to minus 30°C leads to an increase of Ec by 1.6 times according to a linear dependence. An increase of Ec practically ceases in the minus 30–38°C temperature range.
4.  The strength and deformation characteristics of the concrete obtained as a result of tests, which considerably exceed the standard values and those adopted in the design, can be used for analyzing the state of the main structures of the Vilyui III hydrostation during the construction and operation periods and when processing the results of observations by means of the installed monitoring and measuring instruments.
Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 7, pp. 11–14, July, 1998.  相似文献   

15.
Conclusions  
1.  It was proved that the coefficient in front of the existing formulas for determing the critical sediment concentration of flows are not constant, and their values depend on the sediment concentration of the flow in accordance with dependence (12).
2.  A new dependence (13) for calculating the critical sediment concentration of a flow was obtained on the basis of processing numerous existing on-site investigations.
3.  The regime of motion of suspended fine sediments (d≤0.25 mm) in tranquil open-channel flows occurs according to dependence (13).
4.  Formula (13) can be recommended for practical use when calculating the critical sediment concentration in canals, settling basins, and other streams transporting fine natural suspended material.
Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 1, pp. 20–23, January, 1997.  相似文献   

16.
Conclusions  
1.  The bulk of settlement caused by the action of the soil’s own weight occurred in the construction period and were canceled out by the margins left for settlement.
2.  The actual settlement coincide with the calculated.
3.  The settlements observed in section A-A are caused mainly by self-compaction of the soil, since the dynamic action of motor transport is not felt here; in section B-B by the dynamic action of the rolling stock in connection with a low value ofρ d in the track bed; in section C-C by self-compaction of soil, since dynamics from passing trains is not displayed here; along the axes of the crane tracks by the cyclicity of the crane load; the insignificant settlements of several UM marks in the dam foundation are possibly related to compaction of clays as a result of their secondary consolidation, although according to calculations the stresses from the external load die out in sands.
4.  The settlements that occurred, the predicted additional settlements, as well as the sustained settlements of several marks are not hazardous for normal operation of the dam.
Translated from Gidrotekhnicheskoe Stroitel’stvo, No. 3, pp. 46–49, March, 1998.  相似文献   

17.
1.  Intense passage of the sediment deposits washed from the upstream stretches of the reservoir through the cut was observed. In the cut itself or in the immediate vicinity of its outlet, 13,000 m3 of sediments was deposited, the remainder was discharged by the through-flow into the downstream pool.
2.  The cut made was not curvilinear in plan as was intended, and therefore its expected intensive erosion by the flow did not occur. The exception was the inlet stretch of the cut, where its erosion and widening by about 10 m occurred.
3.  An increase of the cross-sectional area of the reservoir due to the cut leads to some decrease of the level of the flushing flow in the main channel and increases its slope on the upstream stretch of the reservoir, increasing the flow velocity and effectiveness of erosion of the sediments. Furthermore, the directions of the flow velocities partially changed in the region of the cut, which intensified the effect of erosion of the sediments.
4.  Gradual erosion of the island of sediment deposits cut off by the cut from the left-bank mass of sediments was observed during flushing and subsequent operation of the reservoir.
5.  It is better to use diesel dredges for making cuts, which, with their self-contained power supply makes it possible to operate on any stretch of the reservoir at a sufficient distance from the bank.
6.  The cost effectiveness of combined removal of sediments can be estimated by comparing the cost of conducting it with the cost of removing sediments by hydraulicking as the cheapest of the presently known methods. For conditions of the Chiryurt reservoir the effectiveness was 0.9 ruble/m3 of sediments being removed for the particular flushing under consideration.
Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 8, pp. 34–37, August, 1989.  相似文献   

18.
Conclusions  
1.  The hydroabrasive resistance of structural steels does not provide the necessary reliability of turbines operating on sediment-transporting rivers.
2.  Case-hardening of structural steels and resistant protective coating are used for increasing the reliability and life of parts of the flow passage.
3.  During actual service the effectiveness of casehardening decreases by half compared with laboratory tests, which is explained by the insufficient thickness of the protective layer. It is not advisable to use this type of surface protection for turbines with a high intensity of hydroabrasive action, since it is impossible to restore the protective layer under hydrostation conditions.
4.  Two types of protective coatings have the highest priority: protective electrode hard surfacing on a cobalt base, for instance, TsN-2, which while providing a high wear resistance of the surface, E greater than 3, permits making a protective layer of the required thickness 3–5 mm and repairing the flow part of the turbine directly at the hydrostation; synthetic polyurethane-based compositions making it possible to completely cover the runners with a coating thickness of 1.5–2 mm. Destroyed polyurethane coatings can be restored directly at the hydrostation.
Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 11, pp. 44–47, November, 1997.  相似文献   

19.
Conclusions  
1.  Gidrospetsproekt should design the groundwater system.
2.  One contractor should drill the wells and operate the groundwater-lowering system.
3.  In connection with the geological conditions, the wells should be of very high quality, for which own enrichment of the filter material (sand of the blanket) and strict control during drilling the wells are necessary.
4.  It is efficient to drill the wells by a 1BA-15V rig with a tool with backwashing.
5.  With respect to piles of the penstock foundation: Drilling the holes for the piles should be done only with casings. To organize 24-h work for increasing productivity. Works on forming the pile heads should be done immediately after concreting the pile. The piles should be tested after each change in the geological conditions.
6.  With respect vertical drainage: the wells should be of high quality, with an enormous safety margin.
Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 10, pp. 29–33, October, 1999.  相似文献   

20.
1.  More than a decade of operation of water-cleaning machines with a conical net has demonstrated their good technical and economic characteristics as regards failure-free operation and water-cleaning performance.
2.  After a simple modification, the existing water-cleaning machines with a vertical axis of cone rotation can perform a fish-protecting function.
3.  For larger water consumers (such as water supply systems of thermal and nuclear power plants) machines with a horizontal cone rotation axis are recommended (so-called directflow water-cleaning machines). With some modernization of the flowthrough component, water offtake facilities can ensure bypass and survival of over 90% of young fish without building any expensive fish guard structures.
4.  Instead of fish guard facilities planned to be built at operating thermal and nuclear power plants, one should consider the possibility of removing the existing water-cleaning machines with flat nets and installing machines with conical nets.
Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 12, pp. 37–40, December, 1990.  相似文献   

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