Hydraulic Power Station Research Articles

Experiment on performance of adjustable jet pump

When the water level of upper or lower reaches of hydraulic power station changes, the adjustable jet pump which is different from traditional fixed jet pump can maintain stable pressure and flow rate for the system of technical water supply of hydraulic power plant. The model test indicates that the efficiency of the adjustable jet pump is slightly lower than fixed jet pump near rating operation point. With the decrease of opening degree, both efficiencies are more and more close to each other. The fundamental performance of I-type adjustable jet pump is better than II-type and the cavitation performance of I-type adjustable jet pump is worse than II-type. Test data also indicate that the performance of adjustable jet pump is very different from fixed jet pump, so the theory of fixed jet pump is not able to be copied to adjustable jet pump. It is necessary to farther study on the performance of the adjustable jet pump. This paper has reference value for analogous design of system of circulation water supply to turbine units in hydraulic power station.

Aerator of stepped chute in Murum Hydropower Station

This paper considers the effect of an aerator type to counter cavitation damage on the stepped chute in Murum Hydraulic Power Station. The shape of the aerator was optimized and the aeration effect was observed by hydraulic modeling. The experimental results revealed that, compared to standard stepped spillway flow, considerable differences were detected in the closely downstream of the aerator. Steady cavities were formed and flow before the point of incipient self-aeration was pre-aerated, and the air concentration of bottom flow on the stepped chute was obviously increased, which means the cavitation damage was successfully avoided.

Study on Grout Permeation Model of an Equipment for Grouting in Roller Compacted Concrete

Based on cylindrical diffusion theory and characteristics of enriched vibrated Roller Compacted Concrete (RCC), a model of grout permeation was established. According to this model and generalized Darcy’s law, a formula was deduced, which shows the relationship among diffusion radius of grout, grouting pressure, radius of grouting pipe, construction time, viscosity of grout, permeability coefficient of RCC, porosity of RCC and rheological index of grout, computing steps by this formula were presented, and results of computing grout diffusion radius for an equipment of grouting in Roller Compacted Concrete was given, which was developed for construction of RCC dam at Tingzikou hydraulic power station.

The Hydraulic Jack-Up System Design on the Ocean Petroleum Platform 161 - the First Self-Installing Product Platforms in China

The paper introduces the hydraulic jack-up system design about the first domestic self-installing product platform. According to the production platform features, the jack-up system chooses the mode of hydraulic cylinder driving. So the jack-up system is both economy and safe reliability. The jack-up system is equipped with proportional valve and the PLC programmable controller which has a touch panel to show the inclination of the platform, the synchronism of hydraulic cylinders in the four legs of the platform, the state of the piston pin and the alarm indication of the hydraulic power station etc.

Modern trends in the development of small hydro power around the world and in Russia

Information on the development of small hydro power is given, specific features relating to construction of modern hydraulic power equipment for small hydraulic power stations are discussed, and experience gained at ZAO MNTO INSET with construction of small hydraulic power facilities in Russia and abroad is briefly described.

Pressure pulsation prediction by 3D turbulent unsteady flow simulation through whole flow passage of Kaplan turbine

PurposeThe purpose of this paper is to predict pressure pulsation in Kaplan hydraulic turbines.Design/methodology/approachState of the art numerical simulation techniques are employed to simulate three‐dimensional flows in the whole flow passage of a Kaplan turbine so that pressure pulsations can be computed in both time domain and frequency domain. Numerical results are verified by experiments carried out on the most advanced experimental platform in China.FindingsIt is found that the proposed numerical model is a viable tool for prediction of pressure pulsations. The simulation shows that the model turbine and prototype turbine have the same pressure pulsation frequencies and rotating frequencies and the same transmission patterns under similar operation conditions. However, there is no similarity for the amplitude of the pressure pulsation between the model turbine and the prototype turbine. Therefore pressure pulsations in a prototype turbine cannot be obtained by scaling the experimental results of the model turbine using a similarity relationship.Practical implicationsThe findings will be very valuable for the design of hydraulic turbines and large‐scale hydraulic power stations.Originality/valueThe proposed numerical method provides a viable tool for hydraulic turbine and power station designers to predict the pressure pulsations in prototype turbines. It is a useful tool to help improve the performance of hydraulic turbines. The findings made in the numerical simulation have been verified by experiments, which is also a valuable reference for hydraulic turbine designers.

Assessment of the efficiency of hydrogen cycles on the basis of off-peak electric energy produced at a nuclear power station

The main factors influencing the efficiency of using off-peak electric energy to run hydrogen cycles at a nuclear power station are considered. Indicators characterizing the efficiency of using a hydrogen cycle at a nuclear power station during its operation with superheating live steam in a steam-hydrogen mode are presented. A comparison between the steam-turbine hydrogen cycle and a pumped-storage hydraulic power station in the efficiency of generating peak electric energy (power) and capital investments is given.

1805 超音波ドップラー流速分布計測法に適したマイクロバブルの数密度について(OS18-1 超音波を利用した流動場の計測,オーガナイズドセッション)

At hydraulic power stations, it is very important to measure inlet flowrate for the plant management. Pitot tubes were commonly used to measure flow rates in steel penstocks for the performance tests of hydraulic turbines. Due to the difficulties of installations of Pitot tubes, transit time ultrasonic flow meters are being popular instead. However, accuracies of transit time ultrasonic flow meters are sensitive for velocity profiles which depend on Reynolds numbers and pipe surface roughness. Recently, ultrasonic pulse Doppler flow meters are considered to be suitable tool for the measurements of flowrates in steel penstock because it can measure instantaneous velocity profiles directly without draining the water in steel penstock. In this paper, we investigate number densities of the micro bubbles as tracer particles for the flowrate measurements using Ultrasonic Pulse Doppler Method.

1807 超音波ドップラー流速分布計測法を利用した水力発電所開渠部の取水流量算出方法の検討(OS18-2 超音波を利用した流動場の計測,オーガナイズドセッション)

1807 超音波ドップラー流速分布計測法を利用した水力発電所開渠部の取水流量算出方法の検討(OS18-2 超音波を利用した流動場の計測,オーガナイズドセッション)

Influence of cavern spacing on the stability of large cavern groups in a hydraulic power station

Many factors influence the static and dynamic stabilities of the rocks surrounding large cavern groups, such as in a hydropower station. In order to study the influence of cavern spacing on the stability of adjacent caverns, two kinds of dynamic-history simulation models for large cavern groups were set up by considering three different strengths of rock masses (soft rock, medium hard rock, and hard rock). One model included two caverns and the other included three caverns. The numerical simulations of these models were conducted under the loading of gravity and the combined loadings of gravity and earthquake motion, separately. To fully consider the dynamic features of rock masses, a damaged plasticity model with a non-associated potential flow was adopted for the surrounding rocks. Due to the stress redistribution and the scattering effect, simulated results indicate that, taking the caverns located in soft rocks, for example, if the spacing is less than one cavern characteristic length (taken to the biggest width of a cavern in the group), the static and dynamic responses of adjacent caverns are significantly affected by their spacing. The damage and the distribution of tensile stress surrounding the caverns are extremely extensive. Once the spacing approaches or exceeds twice the cavern characteristic length, the damage and the distribution of tensile stress of caverns keep unchanged, and the effect of nearby caverns disappears. In some situations, as the rock strength decreases, the damage becomes more severe and the area of tensile stress becomes more extensive. The critical distance of cavern spacing decreases as the strength of the surrounding rocks increases. The conclusions of this work could be used as a primary guidance to the anti-earthquake design for practical engineering.

Effect of Salt Concentration on Performance of Hydroelectic Power Station due to Osmotic Pressure

This paper presents an experimental study about a possibility of a hydroelectric power station due to osmotic pressure generated between sea water and river water. The experiment is conducted by a newly constructed equipment using a spiral reverse osmotic module with membrane surface area 4.318m2. The equipment can be pressured up to 0.5 MPa to avoid a generation of bubble in pure and salt water channels. Tap water and salt water are used for experiment instead of river water and sea water. On the way of tap water passage, a valve is inserted to generate a loss corresponding to a hydraulic turbine load. Using a pump, salt water is forced to circulate and its flow rate is variable. The flow rate of tap water and the pressure difference between the valve inlet and outlet are measured with varying salt concentration from 0.1wt% to 0.6wt% and salt water flow rate from 3.5 1/min to 5.01/min. In these experiments we can obtain a maximum output about 0.86W at salt concentration 0.6wt%. From these results, we had a confidence to construct the hydraulic power station utilizing osmotic pressure.

Ultrasonic pulse-Doppler flow meter application for hydraulic power plants

At hydraulic power stations, Pitot tubes have commonly been used to measure flow rates in steel penstocks for performance testing of hydraulic turbines. Due to the difficulties of Pitot tube installation, transit-time ultrasonic flow meters are becoming a popular replacement, but their accuracy is sensitive to velocity profiles that depend on Reynolds numbers and pipe surface roughness. Ultrasonic pulse Doppler flow meters have recently gained favor as suitable tools to measure flow rates in steel penstocks because they can measure instantaneous velocity profiles directly. Field tests were conducted at an actual hydraulic power plant using an ultrasonic pulse Doppler flow meter, and it was found capable of measuring velocity profiles in a large steel penstock with a diameter of over one meter and Reynolds number of more than five million. Furthermore, two ultrasonic transducers were placed on the pipe surface to validate the multi-line measurement of asymmetric flow. Each transducer recorded the velocity profile simultaneously from the pipe centerline to its far wall during plant operation. Velocity profiles were obtained from three-minute measurements to improve the accuracy of flow rate measurements.

506 揺動式ナノ水力発電機の基礎研究(2)(OS5-2 風力発電,OS5 風力発電,オーガナイズドセッション)

The use of the clean natural/renewable energy resources has been promoted in the power generation, as those scarcely emit greenhouse gases. The waterpower has larger energy density than the wind power and the solar power, and there are many hydraulic power stations. The large-scale station with a dam, however, is undesirable because such public works damage natural ecosystem in rivers andlor forests. To promote more and more the hydroelectric generation for the next leap, it is necessary to utilize effectively mini/micro/nano hydropower in coexisting with natural ecosystem. This research develops a new type hydroelectric unit utilizing the yawing motion of the submerged blades in rivers, irrigation channels, and so on. In this report, the concepts of the unit are explained, and the output characteristics are discussed experimentally using the trial model.

The Short-Term Hydrothermal Coordination via Genetic Algorithms

This article presents a solution for the short-term hydrothermal generation scheduling problem (HGSP) by using a genetic algorithm. The hydrothermal coordination is solved using an equivalent cost function for the available thermal units, while the unit commitment and the economic dispatch are solved by considering the more capable individuals obtained from the hydrothermal coordination stage. Quadratic cost functions for the thermal units and a second grade equation depending on the volume and the flow for the active power calculation of the hydraulic generation are considered. The appropriateness of the proposition is proved in two power systems: The first system is composed of 4 hydraulic power stations and 10 thermal units, while the second system is composed of 16 hydraulic power stations and 30 thermal ones.

The Controller of the Grinding and Welding Manipulator

The low efficiency and inaccurateness always annoys the great hydraulic power station. This paper presents the constitution of the welding and grinding manipulator in order to repair hydraulic turbine guide vane, with the computer directly control and its hardware and software. It emphasizes on the control method based on the position/force control, and also includes the 3-D graphic, based on OpenGL and the data management with database.

水車遺構に見る動力伝達機構の研究:その5 : 小水力発電における使用事例から(S70-1 機械技術史・工学史(1),S70 機械技術史・工学史)

In the area where electricity from the 1920s to the 1930s wasn't installed, the resident cooperated and did electric business. In Tsukude-mura, Minamishitara District, Aichi Prefecture, a small-scale hydraulic power st at ion was constructed to seven in the village. Ruins at the hydraulic power station such as the water turbine and the watercourse are left at Suzuki Hisao's home of the one. It discussed based on the field survey about the actual state and the characteristic of the power transmission at the small-scale hydraulic power station.

Hydrogen production from excess power in small hydroelectric installations

A brief review shows that hydrogen production from small hydraulic power systems is thermodynamically and technically feasible. Particularly, excess power in existing installations may be used to make the hydrogen production economically feasible. In this study, a simulation model has been developed regarding hydraulic power and hydrogen production systems, and a cost and economics to find out the economical feasibility of hydrogen production. The simulation code is used to carry out a parametric study of small hydraulic power—hydrogen production systems, and also feasibility of existing hydraulic power stations in a case study. In the latter case, the data from 13 installations in Turkey have been used. It has been found that the hydrogen production rate is about 100 ton /year/MW installed power of electrolytic process plant and the cost varies from 3.9 to 8.6 $/GJ (0.55 to 1.21 $/kg) when the hydrogen production plant capacity factor is above 50%.

A VIBRATION FINDING SURVEY OF EXISTING STEEL PENSTOCKS AND NATURAL FREQUENCY CALCULATION FORMULAE

When a momentary pressure pulsation takes place in a turbine, and its frequency coincides with the natural frequency of a steel penstock, resonance occurs resulting in noticeable vibration. While the current tendency is to increase the rotation frequency of turbines, penstock plates are gradually becoming thinner. As a result of these trends, the occurrence of oval vibration has been reported at some hydraulic power stations. Since rules on vibration prevention do not always include oval vibration, we sought out detailed information on existing penstocks constructed within the last 30 years. Based on this information and a numerical study, formulae to calculate the natural frequencies of steel penstocks including those with circumferential stiffeners were proposed.

Water resource and power generation

We propose a simple model of competition between a thermal station and a hydrostation for the production of energy. We show that, despite the static characteristics of the thermal cost function, the thermal output is determined by intertemporal considerations. This results from the scarcity of the water resource which is storable at zero operating cost. We analyze the combination of these technologies in the case of a social planner who maximizes the net total utility from electricity, in the case of private monopoly either regulated or not and, finally, in the case of duopolistic competition in quantities where each private firm operates either a hydraulic power station, or a thermal power station.

原位置ＡＥ計測に基づいた岩盤ゆるみ域の評価

When constructing large underground caverns such as hydraulic power stations and oil storages, it is important to estimate the loosened area around rock caverns caused by excavation. If the loosened area around a rock cavern is known, the most suitable support members and quantities can be determined. The authors have carried out in situ experiment to investigate the crack growth into rock mass by acoustic emission (AE) measurement.In this paper, parameter analysis, locational analysis and moment tensor analysis based on the observed AE signal waves were carried out to make clear the diffusing patterns, locations, orientations and crack types of AE sources. The following conclusions were obtained: (1) Many large amplitude AE signal waves diffused within about ten minutes after cavern blasting, (2) The concentrated areas of tensile cracks and shear cracks around a rock cavern were different, (3) From the distribution of observed AE signal waves, the loosened area was estimated within depth of 2m from the excavated wall.