RU2020241C1 - Hydraulic turbine and method of passing water through it - Google Patents

Abstract

FIELD: hydraulic power engineering. SUBSTANCE: water conduits under increased pressure of air are located along stator generatrix. Arranged is stator is rotor made in form of polyhedron with fixed plate blades of similar length. Blades form inter-blade chambers together with stator. Stator is cylindrical in shape and water conduits are straight-flow. Rotor is mounted coaxially in stator-provided with U-shaped air duct for air communication of stator parts adjoining the water conduits and transfer of air circulation beyond the stator limits. Upper portion of air duct is located at the level of water-head. Water is supplied to the chambers from water-head and waste water is discharged to tail-water. Part of waste water drops in reverse direction: from tail-water to water-head. EFFECT: enhanced reliability. 3 cl, 4 dwg

Description

 The invention relates to techniques for hydropower and fish access devices. Primary application: for pressures from less than 0.5 m at tidal power plants to medium pressures at hydro power plants. A hydraulic turbine passes fish through the waterway in both directions.

 The purpose of the invention is to increase the pressure on the turbine without increasing the diameter of the rotor, i.e. ensuring independence of pressure from the diameter of the turbine rotor.

 In the prototype, the difference between the downstream flows is always equal to the difference in water under the stator, but the latter can never be more than 0.3 D rotor for structural reasons.

 Under the stator of the prototype, the entire circulation of compressed air in the direction opposite to the rotation of the rotor occurs, the air path begins and ends. The subsistor circulation of compressed air connects the pressure of the prototype with the diameter of the rotor. The prototype works on the principle: the larger the diameter of the rotor - the greater the pressure on the turbine.

 The goal is to increase the pressure on the turbine, i.e. independence of the pressure on the rotor diameter is achieved by installing a cylindrical stator and a U-shaped duct on the turbine, which makes the air circulation (air duct) outside the stator above the elevation mark. Therefore, the pressure on the turbine is determined not by the diameter of the rotor, but by the height of the duct, taking into account the immersion depth of the turbine for the migration of fish. The greater the height of the duct — the greater the pressure on the turbine — this is the principle of determining the pressure on the proposed turbine.

 The goal is achieved by moving the air path outside the stator, i.e., to the duct, which should always be above the elevation mark.

 An additional goal is to improve the ecological characteristics of the turbine by ensuring the migration of fish from the downstream to the upstream.

 In the prototype, fish can migrate with water through the turbine only in the forward direction from the upstream to the downstream. In the opposite direction, the fish cannot migrate.

 To do this, the water spent on the rotor with the help of a U-shaped duct and air of a certain pressure is not completely squeezed out of the chambers, but is divided into two streams, one of which is led out of the turbine and the other circulates in the chambers of the rotor, creating a reverse water flow within the stator, with which migrates the fish from the lower pool to the upper one.

 An additional goal is to simplify the design of the turbine and increase efficiency.

The water pipes of the prototype are indirect, curly, the water in each of them changes direction by 360 ^o , which reduces the efficiency.

 For this, rectilinear water conduits are installed, which simplifies the design and increases the efficiency.

 An additional goal is the bilateral operation of the turbine.

 The prototype is a single-acting turbine, since the stator is asymmetrical to increase the pressure when the water moves in one direction, which determines its purpose only for hydroelectric power plants. The asymmetry in pressure excludes its use in PES.

 Bilateral work is achieved by installing a cylindrical stator, a U-shaped duct, as well as symmetrical stator and water ducts.

 In FIG. 1 shows a cross section of a hydraulic turbine; figure 2 is a section aa in figure 1; figure 3 is a cross-section of the turbine on the dam in the pre-launch position (shows the marks of the upper and lower pools, as well as the marks of water in the duct and turbine in various modes); figure 4 is a longitudinal section along the dam.

 A hydraulic turbine consists of two main components: a stator and a rotor. The stator is a horizontal cylinder 1, which is attached to the supporting disks by the ends 2. On the stator along the entire length of the generatrix there are installed conduits 3 with oblique flanges 4.

 The rotating part of the turbine - the rotor has the form of a multi-faceted drum 5 with end disks 6 at the ends, which are centrally mounted on the rotor shaft 7. The latter is supported through the bearing 8 on the supporting disks 2. Fixedly mounted plates 9 of equal length are fixed to the faces of the drum 5, forming between themselves and the stator of the chamber 10. Between the plates 9 and the stator creates a guaranteed clearance. The rotor shaft 7 at the ends has couplings 11.

 Figure 1 shows that the proposed turbine is symmetrical, therefore, it can be used at tidal stations.

The cross section of the turbine (Fig. 1) can be divided into three functional zones:
1. Energy (working) zone - below the water mains. Here the energy of falling water is converted into torque;
2. The passage zone coincides with the water conduits;
3. The reverse (idle) zone is above the water conduits.

 In order to increase the pressure on the turbine, the possibility of raising fish through the turbine, as well as more efficient cutting off high pressure from low pressure (increasing efficiency, reducing leakage) on the stator, in its upper part, a U-shaped duct 12 is installed for air communication of parts adjacent to the water ducts stator and extrusion of waste water on the rotor. A U-shaped duct extends the air path outside the stator, which makes the pressure on the turbine independent of the diameter of the rotor, and dependent only on the height of the duct.

 The duct must always be above the elevation, otherwise it will turn into a water conduit and the turbine will stop.

 Depending on the degree (completeness) of squeezing water from the chambers 10 on the turbine, two fundamentally different operating modes can be used (Fig. 3).

The first mode is the main one and is intended only for hydroelectric power stations for obtaining energy and passing fish through the turbine in both directions. From the upper pool to the lower fish, through a turbine, it migrates with a direct water stream through the energy zone. To create conditions for the migration of fish through the turbine from the downstream to the upper turbine, a reverse water stream is created in the reverse zone within the stator within the stator, which is formed by incomplete extrusion of water from chambers 10 to the level of H ₁ ¹ above the axis of the turbine at outlet duct 3 using compressed air pressure P supplied to the duct and determined by the formula P = H ₁ - H ₁ ¹ , where H ₁ is the mark of the downstream.

The air pressure P does not depend on the elevation headwater Н ₂ .

 Chambers 10 transfer fish from the downstream to the upstream as part of the reverse watercourse. In this case, the fish independently enters and leaves the return watercourse, going all the time against the current, which does not contradict the fish instinct to move against the current for spawning. Unpowered water from the chambers is re-circulated on the rotor, maintaining the continuity of the reverse water flow in the upper part of the turbine.

 In this mode, 10-30% of the total water volume remains in chambers 10 depending on the size of the fish and the diameter of the turbine, which reduces the same power.

 The energy costs of creating a reverse watercourse and raising the fish consist only of losses due to friction of water in the chambers and losses due to friction of air in the duct.

Figure 3 shows the water mark H ₁ ¹ at the outlet conduit, guaranteeing the creation of a reverse water flow within the stator.

 Thus, a feature of the first mode (only for hydroelectric power stations) is the incomplete extrusion of waste water from the chambers 10 and the creation of a reverse water stream on the turbine for lifting fish.

In this mode, there are three immiscible but mutually interconnected flows in the turbine cross section:
direct watercourse, it is also energy and fish passage;
air flow that moves along the air path: reverse zone - air duct;
a circular flow of water not displaced from the chambers, which forms a reverse water stream in the upper part of the turbine.

The second mode is characterized by the complete extrusion of water from the chambers 10 without creating a reverse watercourse and without raising the fish from the lower pool to the upper one. Extrusion of waste water on the rotor is carried out up to the mark N ^P ₁ below the axis of the turbine. This mode is intended only for PES, where the water on the dam several times a day changes direction according to the laws of the tide. Therefore, the fish can alternately migrate in both directions with a direct watercourse without creating a reverse watercourse. At a PES, the turbine can operate in the first mode, if environmental circumstances force this to happen.

 The advantages of the second mode over the first at the PES are in increasing the turbine power by 10-30% due to the lack of reverse water flow.

Since the downstream elevation mark N ₁ at the TEC is variable due to the tidal properties, and the elevation mark ^{P P} ₁ must be unchanged, so that the air pressure P in the duct 12 must be a variable to keep the mark N ^P ₁ unchanged - conditions for complete displacement from chambers 10 This is a feature of the operation of the turbine at the PES. The variability of the air pressure P in the duct is provided both by the compressor itself and by special devices.

 Several turbines (10-15) can, with the help of couplings 11 and intermediate shafts 13, be combined into a block and work on one generator 14. This will reduce the number of generators, increase their unit power and efficiency.

 In FIG. 4 shows a longitudinal section through the dam of the hydroelectric power station, turbine blocks with their own generators 14. To increase the torque, several blocks using couplings 11 and intermediate shafts 13 can be combined and work on one generator, and the intermediate generators work like shaft shafts.

 Air ducts 12 of all turbines of the station are connected to the main pipeline 15 stretched along the dam, for which the compressor 16 operates.

 In connection with the design features of the turbine, the dam for its placement has two ridges 17, between which there is a machine room, and in it turbine blocks. In the ridges 17 there are dam conduits 18. Between the last and turbine conduits 3 with the help of oblique flanges 4 and flexible seals a tight and at the same time flexible connection is created.

 Thus, the entire external part of the turbine and its supporting parts are out of the water, which facilitates its operation, as well as repair and installation work. Gates 19 are installed on the dam water conduits 18, which can isolate the turbine from the downstream.

 Start and operation of the turbine is carried out by the following operations.

1. The turbine rotor is locked for a more precise start and tracking of the levels of waste water (N ₁ ¹ and N ^P ₁ ) and to clarify the air pressure R. Dam valves 19 open (figure 3).

2. Compressed air of a certain pressure is supplied to the duct and water is displaced from the chambers from the outlet conduit to the H ₁ ¹ mark (incomplete squeezing of water from the chambers is a condition for creating a reverse water flow for raising fish from the lower pool to the upper one) or to the N ^P ₁ mark ( complete extrusion of water from the chambers without creating a reverse watercourse.This position is pre-start and it is fixed in figure 3. In this position it is clearly seen that the difference between the downstream flows Н ₂ -Н ₁ = Н is transferred under the air duct, where the same difference between the downflows is H = H ¹ ₂ - H ₁ ¹ according to the law of communicating vessels .. Under the marks N ₁ ¹ or N ^P ₁ in the pre-start position, the air pressure P in the duct is regulated.

3. After reaching the required marks Н ₁ ¹ or Н ^П ₁ - a sign of an exact exit to the calculated mode by air pressure, the rotor is removed from the stoppers, scrolling starts, during which time water from the duct adjacent to the upstream drain flows onto the rotor. The circular movement of compressed air begins in the airway. Then the turbine enters the operating mode by the number of revolutions, marks N ₁ ¹ or N ^P ₁ , the creation of a reverse watercourse. Keeping these marks close to the calculated ones creates optimal conditions for the operation of the turbine.

 With a steady state operation in the turbine, the following occurs. Compressed air at the outlet conduit displaces the water from the chambers 10, and at the same time, the water of the upstream displaces the air from the chambers at the inlet conduit. In this case, the compressed air is pumped by the chambers 10 along the air path in the direction opposite to the rotation of the rotor. In order to more smoothly displace air from the chambers 10 with water of the upper pool, a throttle can be installed in the upper part of the duct 12.

 Since the air path (the upper part of the stator and the duct) is a closed volume, there will be no loss of compressed air from this volume, except for small losses for its dissolution in water. This is an additional positive effect, since the water in the lower pool is enriched with atmospheric oxygen, which increases the biological value, especially in winter.

 The most important characteristic of low-pressure turbines for flat hydroelectric power plants, and especially for PES, is the minimum pressure at which the turbine block can still create excess torque in excess of idling and efficiency.

 Simple calculations using well-known formulas show that to scroll a composite unit (turbine block and generator) idle, a pressure of about 10 mm is required, and any pressure in excess of this creates excess torque, which can be converted into energy by known methods, with an efficiency of about 90% of for the small losses in the gaps and the absence of turbulence. The prototype can work at the same low heads, but high heads are not accessible to it, for this the rotor diameter should increase to tens and hundreds of meters.

 The lowest pressure capsule hydraulic turbine at pressures less than 1 m does not work, and the efficiency at such an extremely low pressure is about 10%.

 The main advantages of the proposed turbine over the prototype and its analogues are the ability to work on pressures from less than 0.1 m at PES to high at HPPs, high efficiency, high unit power even at low pressures and, most importantly, environmental cleanliness. Among analogues there are no turbines with such indicators in terms of pressure, efficiency and environmental indicators.

 The turbine can be used on existing waterworks and reservoirs with small differences (2-6 m), where they do not receive electricity due to the lack of low-pressure turbines with the possibility of bilateral migration of fish. There are more than 400 such facilities in the country. Installing a given turbine with a generator on them will turn them into hydroelectric power stations without capital investments and environmental justifications.

 The turbine can be used in the construction of small hydropower plants on lowland rivers. The energy reserve for them is 320 billion kWh, which is equal to the generation of all the country's hydroelectric power stations. The pressure at such hydropower plants will be less than 3-6 m, for which there are no fish-passing turbines in both directions.

 Especially promising is the use of the inventive turbines at TECs for which there are no low-pressure turbines with a head pressure of less than 0.1 to 10 m. Moreover, the capacity of well-known TEC projects increases by 40-80% both due to the use of a differential of less than 1 m, and due to more high turbine efficiency. Tidal energy reserves in the country are estimated at more than 250 million kW, which is comparable with the capacity of all stations in the country. World reserves of tidal energy are estimated at 1-8 billion kWh.

 The proposed turbine can be effectively used on all existing lowland hydroelectric power stations instead of vane turbines, fish-blocking and plankton-destroying. This improves the ecological situation on the rivers; they will become fish passageways as before the construction of the hydroelectric power station.

 The cascade of low-pressure hydroelectric power stations on a flat river with fish culverts according to this application is preferable to one high-pressure hydroelectric power station of equal capacity in terms of technical, environmental and other indicators. At the same time, the area of flooded lands will be reduced.

 An additional effect higher than in the country can be obtained from patenting a turbine abroad. A higher effect can be obtained from the use of a turbine in tidal energy, whose reserves are 2000 times greater than the reserves of hydropower of all the rivers of the world.

 Since the turbine is low-pressure and fish-passable, this circumstance can increase the economic potential of the resource to 175-200 million kW by reducing losses on evaporation, filtration, increasing efficiency, and building a hydropower station in the mouths.

 The entire water resource, amenable to implementation using the inventive turbine, will be about 175 + 250 = 425 million kW. At the required rate of annual increase in energy capacities in the country of about 10 million kW, this resource is enough to increase energy capacities only from these cheapest, environmentally friendly and renewable sources for 40-50 years. At the same time, the production of organic and nuclear fuel will decrease, which means that their environmental impact on the biosphere will be reduced both in the places of production and in the places of burning.

 From the above, it can be concluded that it is advisable to refuse the construction of most NPPs and TPPs in this period in favor of environmentally friendly HPPs and TPPs, as cheaper, environmentally friendly and renewable.

Claims (2)

 1. A hydraulic turbine containing a stator under increased air pressure, located along its generatrix conduits and a rotor located in the stator, made in the form of a polyhedron with fixed plate blades of the same length, forming inter-vane chambers with the stator, characterized in that the stator is cylindrical, direct-flow conduits, the rotor is mounted coaxially in the stator, and the latter is equipped with a U-shaped duct for air communication of the stator parts adjacent to the water ducts and for transferring air circulation outside torus, wherein the upper portion of the duct located above the level of the upper pool.  2. A method of passing water through a hydraulic turbine, comprising supplying water to the inter-blade chambers from the upstream and withdrawing waste water from the latter to the lower downstream, characterized in that part of the waste water the interscapular chambers are fed in the opposite direction - from the lower downstream to the upper.

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