CN101566120A - Hydropower station tail water supercharging and high-efficient power generation system - Google Patents

Abstract

The invention discloses a hydropower station tail water supercharging and high-efficient power generation system, which is characterized in that: the draft tube caliber is larger than the caliber of the pressure pipe, and the low pressure current of the draft-tube is pressured by the pressure device, and is reinjected into the pressure pipe. Difference values of current speeds and pressure intensities between the pressure pipe and the draft-tube are increased, thereby the kenetic energy and pressure energy components in the water energy translated into electric energy are increased for improving generating efficiency.

Description

Hydropower station tail water supercharging and efficient power generation system

Technical field

The present invention relates to a kind of hydropower station tail water supercharging and efficient power generation system, belong to the hydroelectric power field.

Background technique

The water power plant utilizes reservoir to come retaining, and reservoir capacity is big more, and the water yield of storage is big more, and the water that reservoir stores can be just many more.Have the current of certain flow rate to have kinetic energy, the kinetic energy size is directly proportional with square of flow velocity; The current that are in certain altitude have potential energy, and the big more potential energy that has of relative height is just big more.Current flow to lower from eminence, potential energy can be converted into kinetic energy, make current obtain higher speed.The water of saving in the reservoir obtains high speed under action of gravity, move along pressure diversion conduit is defeated downwards, obtains higher speed at the water turbine jointing.Water current driven water turbine with certain speed rotates, and makes water turbine obtain mechanical energy; The water wheels machine driving generator is converted into electric energy with mechanical energy.Water power plant hydraulic generator unit output Power Calculation formula all adopts following mathematical formulae traditionally:

P＝9.80ηQH (1)

P is a hydraulic generator unit output power (kW) in the formula (1), and Q is generating flow (m ³/ s), H is generating net water head (m), η is the water turbine generating efficiency.

Formula (1) is to draw under hypothesis pressure diversion conduit ingress water velocity, pressure and prerequisite that water turbine water outlet place water velocity, pressure equate.That is to say that the Traditional calculating methods of hydraulic generator unit output power includes only potential energy, and do not comprise kinetic energy, pressure energy.Traditional calculating methods, do not consider that water flow dynamic energy and pressure energy move at reservoir, pressure diversion conduit, water turbine, the defeated of draft tube, therefore on structure and technology, reservoir, pressure diversion conduit, water turbine, draft tube are not carried out specific aim improvement and optimization yet, make that water can not obtain fully and efficiently utilizing.

The electric energy that the hydraulic generator unit is transformed from reservoir water body potential energy, kinetic energy and pressure energy main and reservoir drop, pressure diversion conduit ingress water velocity, pressure diversion conduit ingress water flow pressure and reservoir filling water level etc. have relation.

HYDROELECTRIC ENERGY is to be the main resource of taking into account other comprehensive utilizations with the generating, in order to carry out reasonable optimizing to its utilization, must obtain its total amount by mathematical method, sets up functional model.HYDROELECTRIC ENERGY is the Conversion of energy of being contained by natural water resources, mainly is to be present in the energy that pressure energy, potential energy, impact kinetic energy and water body gravity acting in the water body are produced.

(1) energy that has of water inlet water body infinitesimal

Suppose that water power plant unit pressure deferent is cylindrical, one of water inlet little length on the x direction is the water body infinitesimal of dx, and then the stressed of this water body infinitesimal has gravity, hydraulic pressure to reach the reservoir water body weight component by force to its active force.Under these active force actings in conjunction, the water body infinitesimal to the outlet campaign and promote the water wheels unit and rotate, is finally realized the coupling conversion of water energy-mechanical energy-electric energy along the pressure diversion conduit import, and the hydraulic generator unit produces electric energy output.

By the effect of tail water pressurizing system, the draft tube low-pressure water pressurization device of flowing through adds pressure injection backwater turbine water intake, in such cases, pressure along the pressure diversion conduit durection component to water body infinitesimal institute's work or the energy W that had _IFor:

$W_I=(P_I+P_A)\·V_W=\frac{1}{4}{\mathrm{\πD}}^2(P_I+P_A)\mathrm{dx}=\frac{1}{4}\mathrm{\π\ρg}{D}^2(H-H_I+P_A)\mathrm{dx}---\left(2\right)$

P wherein _I, V _W, H _I, D is pressure, volume, water level, the diameter of pressure diversion conduit ingress water body infinitesimal, P _ABe the pressure that the tail water supercharging system is increased, H is the reservoir filling water level, and ρ is the proportion of water, and g is a gravity accleration.

Water body infinitesimal weight at the formed pressure in pressure diversion conduit ingress along component institute's work of pressure diversion conduit direction or the energy that is had is:

$M_I=p_M{V}_M=\frac{1}{4}{\mathrm{g\&pi;<figure-callout\; id="2"\; label="D"\; filenames="A20091011411300101.png"\; state="\{\{state\}\}">D</figure-callout>}}^2\mathrm{\&rho;}\tan \mathrm{\&alpha;}\&CenterDot;d^{2}x---\left(3\right)$

In the formula (3), α is the pressure diversion conduit tilt angle.

If weight is m _W, volume is V _WThe speed of water body infinitesimal in the pressure diversion conduit water inlet be v _{I, j, i}, then its kinetic energy that has is:

$K_I=\frac{1}{2g}{m}_W{v}_{\mathrm{<figure-callout\; id="2"\; label="I"\; filenames="A20091011411300101.png"\; state="\{\{state\}\}">I</figure-callout>}}^2=\frac{1}{2g}\&CenterDot;\frac{1}{4}{\mathrm{\&pi;\&rho;<figure-callout\; id="2"\; label="D"\; filenames="A20091011411300101.png"\; state="\{\{state\}\}">D</figure-callout>}}^2\mathrm{dx}\&CenterDot;v_{\mathrm{<figure-callout\; id="2"\; label="I"\; filenames="A20091011411300101.png"\; state="\{\{state\}\}">I</figure-callout>}}^2=\frac{1}{8}{\mathrm{\&pi;\&rho;<figure-callout\; id="2"\; label="D"\; filenames="A20091011411300101.png"\; state="\{\{state\}\}">D</figure-callout>}}^2\mathrm{dx}\&CenterDot;v_I^2---\left(4\right)$

Weight is m _W, volume is V _WThe water body infinitesimal have potential energy in pressure diversion conduit water intake place and be:

$E_I=m_W\&CenterDot;H_I=\frac{1}{4}{\mathrm{\&pi;\&rho;gD}}^2{H}_I\&CenterDot;\mathrm{dx}---\left(5\right)$

(2) energy that has of water outlet place water body infinitesimal

To moving to the water body infinitesimal in downstream after the water turbine acting, suppose that the pressure of water power plant hydraulic generator unit at water turbine water outlet place is p _O, then this pressure is m to weight _W, volume is V _WWater body infinitesimal institute work be:

$W_O=p_O\&CenterDot;V_W=\frac{1}{4}{\mathrm{\&pi;D}}^2{P}_O\mathrm{dx}---\left(6\right)$

Weight is m _WThe water body infinitesimal at the formed pressure in cross section, water turbine water outlet place be along component institute's work of pressure deferent direction or the energy that is had:

$M_O=M_I=\frac{1}{4}{\mathrm{g\&pi;<figure-callout\; id="2"\; label="D"\; filenames="A20091011411300101.png"\; state="\{\{state\}\}">D</figure-callout>}}^2\mathrm{\&rho;}\tan \mathrm{\&alpha;}\&CenterDot;d^{2}x---\left(7\right)$

If weight is m _W, volume is V _WThe speed of water body infinitesimal at water turbine water outlet place be v _O, then its kinetic energy that has is:

$K_O=\frac{1}{2g}{m}_W{v}_{\mathrm{<figure-callout\; id="2"\; label="O"\; filenames="A20091011411300101.png"\; state="\{\{state\}\}">O</figure-callout>}}^2=\frac{1}{2}\&CenterDot;\frac{1}{4}{\mathrm{\&pi;\&rho;<figure-callout\; id="2"\; label="D"\; filenames="A20091011411300101.png"\; state="\{\{state\}\}">D</figure-callout>}}^2\mathrm{dx}\&CenterDot;v_{\mathrm{<figure-callout\; id="2"\; label="O"\; filenames="A20091011411300101.png"\; state="\{\{state\}\}">O</figure-callout>}}^2=\frac{1}{8}\&CenterDot;{\mathrm{\&pi;\&rho;D}}^2{v}_{\mathrm{<figure-callout\; id="2"\; label="O"\; filenames="A20091011411300101.png"\; state="\{\{state\}\}">O</figure-callout>}}^2\mathrm{dx}---\left(8\right)$

Weight is m _W, volume is V _WThe water body infinitesimal at the potential energy that water turbine water outlet place has be:

$E_O=m_W\&CenterDot;H_O=\frac{1}{4}{\mathrm{\&pi;\&rho;gD}}^2{H}_O\&CenterDot;\mathrm{dx}---\left(9\right)$

H wherein _OElevation for water turbine water outlet place, water power plant.

(3) the unit electric energy calculates

Hydroturbine water intake mouth place water body infinitesimal moves to the water turbine water outlet after water turbine is done work, and according to law of conservation of energy, energy or merit that water turbine obtains are:

$E_G=W_I+K_I+E_I+M_I-W_O-K_O-E_O-M_O$

$=\frac{{\mathrm{\&pi;D}}^2(P_I+P_A-P_o)\mathrm{<figure-callout\; id="4"\; label="dx"\; filenames="A20091011411300101.png"\; state="\{\{state\}\}">dx</figure-callout>}}{4}+\frac{{\mathrm{\&pi;\&rho;D}}^2(v_I^2-v_o^2)\mathrm{<figure-callout\; id="8"\; label="dx"\; filenames="A20091011411300101.png"\; state="\{\{state\}\}">dx</figure-callout>}}{8}+\frac{{\mathrm{\&pi;\&rho;gD}}^2(H_I-H_o)\mathrm{dx}}{4}---\left(10\right)$

Make k _pThe ratio of the pressure summation that is increased for Hydropower Plant water turbine water outlet place and pressure deferent water inlet water body pressure and tail water supercharging system:

$k_P=\frac{p_O}{p_I+p_A}---\left(11\right)$

k _vBe the ratio of step power station unit water turbine water outlet place with pressure deferent water inlet water volume flow rate:

$k_v=\frac{v_O^2}{v_I^2}---\left(12\right)$

H _DBe the drop between Hydropower Plant pressure deferent water inlet and the water turbine water outlet place:

H _D＝H _I-H _O (13)

Water turbine is transferred to generator with the energy that obtains by driving generator, if conversion efficiency is η, energy or function electric power that generator obtains are represented, are unit (1kW=102kg.m/s) with kW, and what then the hydropower generator group was produced in period dt exerts oneself and can be expressed as:

$N_G=\frac{1000}{102}\&CenterDot;\mathrm{\&eta;}[(1-k_P)(p_I+p_A)+\frac{\mathrm{\&rho;}}{2}{v}_I^2(1-k_v)+{\mathrm{\&rho;gH}}_D]Q_G---\left(14\right)$

Q wherein _GBe the unit generation flow, $Q_G=\frac{1}{4}{\mathrm{\&pi;D}}^2{v}_I,$ $v_I=\frac{\mathrm{dx}}{\mathrm{dt}}.$

To formula (14) arrangement:

$N_G=9.80\&CenterDot;\mathrm{\&eta;}[(1-k_p)(p_I+p_A)+\frac{1}{2}{\mathrm{\&rho;v}}_I^2(1-k_v)+\mathrm{\&rho;g}{H}_D]Q_G---\left(15\right)$

From formula (15) as can be seen, the water power plant available water of hydraulic generator unit can comprise water body pressure energy, kinetic energy, potential energy, exerting oneself not only of hydraulic generator unit is relevant with water power plant drop, generating flow, conversion efficiency, and also importing and exporting the pressure, speed of water body, pressure that the tail water supercharging system increased and the parameters such as storage capacity feature in water power plant with pressure diversion conduit has substantial connection.

Traditional hydraulic generator unit all is to adopt the Traditional calculating methods of above-mentioned formula (1) to determine its electric motor power.

Author of the present invention draws as drawing a conclusion through research for many years:

1) hydroelectric generator can be converted into mechanical energy by reservoir, pressure diversion conduit, water turbine, generator and draft tube with water and be converted into electric energy, and electric energy comprises three kinds of components such as kinetic energy, potential energy and pressure energy.

2) the kinetic energy component is directly proportional with the difference of two squares of pressure diversion conduit water inlet place and water turbine water outlet place water velocity.Pressure diversion conduit water inlet place water velocity is controlled water turbine water outlet place water velocity little greatly, and the kinetic energy component will increase; Pressure diversion conduit water inlet place and water turbine water outlet place water velocity equate that the kinetic energy component is 0.

3) the pressure energy component is directly proportional with the difference of pressure diversion conduit water inlet place and water turbine water outlet place current pressure.Current suffered pressure in pressure diversion conduit water inlet place controls water turbine water outlet place current pressure little greatly, and the pressure energy component will increase; Pressure diversion conduit water inlet place and water turbine water outlet place water velocity equate that the pressure energy component is 0.

Summary of the invention

Based on above-mentioned analysis, technical problem to be solved by this invention is, a kind of generating power effectively by hydroelectric generator method and system are provided, and makes full use of the kinetic energy component, and the kinetic energy transformation efficiency is improved, and realizes hydroelectric power more efficiently.

Technological scheme of the present invention is as follows:

The generating power effectively by hydroelectric generator method is made horn shape with draft tube, and promptly the water outlet aperture of draft tube increases by a cover pressurization device simultaneously greater than the water intake bore at the draft tube place.Its role is to,, obtain pressure deferent water intake v by enlarging the draft tube water outlet aperture _IWith water turbine water outlet v _OBigger difference.At water turbine water outlet v _OUnder the less situation, when draft tube can transport the generating flow the same with pressure diversion conduit, make kinetic energy be converted into electric energy more; By giving pressure diversion conduit to draft tube low pressure current pressurization re-injection, increase the differential water pressures of water inlet and water outlet, when draft tube can transport the generating flow the same with pressure diversion conduit, make pressure energy be converted into electric energy more.

The hydropower station tail water supercharging system comprises connecting tube, supercharging device, pressure inlet, it is characterized in that: the draft tube low-pressure water is annotated back pressure power aqueduct through pressurization device pressurization back, increase the difference of water outlet hydraulic pressure and water intake hydraulic pressure.

The generating power effectively by hydroelectric generator system comprises reservoir, pressure diversion conduit, water turbine, generator, draft tube, it is characterized in that: draft tube is a divergent shaped draft tube, and promptly the water outlet aperture of draft tube is greater than the water intake bore.

Above-mentioned generating power effectively by hydroelectric generator system, described divergent shaped draft tube, its sectional shape can be circle, or oval, or triangle, or square, or polygonal.

The invention has the advantages that: carry out innovative design by draft tube system and tail water processing system to hydroelectric power system, increase the difference of pressure diversion conduit and divergent shaped draft tube water velocity, hydraulic pressure respectively, kinetic energy, pressure energy component are converted into electric energy in the water energy thereby increase, improve generating efficiency, the utilization ratio of water energy is also just higher.

Description of drawings

Accompanying drawing is the schematic representation of hydropower station tail water supercharging of the present invention and efficient power generation system.

Embodiment

As shown in the figure, 1 is reservoir, and 2 is pressure diversion conduit, and 3 is water turbine, and 4 is generator, and 5 is draft tube, and 6 is connecting tube, and 7 is pressurization device, and 8 is pressure inlet.The water intake of pressure diversion conduit 2 is connected with reservoir 1, and the water outlet of pressure diversion conduit 2 is connected with the water intake of water turbine 3.The water outlet of water turbine 3 directly is connected with the water intake of big caliber draft tube 5, draft tube 5 water outlets link to each other by connecting tube 6 with supercharging device 7 water intakes, supercharging device 7 water outlets are connected with the water intake of pressure inlet 8, and the water outlet of pressure inlet 8 is connected with the water outlet of pressure diversion conduit 2 and the water intake of water turbine 3.

Pressure diversion conduit 2 with bore 8m is an example, flow velocity degree for water turbine 3 pressure diversion conduit water 2 is 8m/s, under situation about not considering through the influence of the variation of water turbine 3 back water velocities and other factors, if divergent shaped draft tube 5 water intake bores are 8m, water outlet aperture is the twice of the bore of pressure diversion conduit 2, divergent shaped draft tube 5 is when transporting the generating flow condition the same with pressure diversion conduit 2 so, and the water velocity of the divergent shaped draft tube 5 of flowing through can be changed into 4m/s.If consider that part kinetic energy component is converted into mechanical energy by water turbine 3 in the water energy, the water velocity of divergent shaped draft tube 5 will be less than 4m/s so, even can be below 1-2m/s.

Water power plant with the tailing water-pressurization system is an example, when supposing not the tailing water-pressurization system, and water turbine water outlet pressure P _OWith pressure diversion conduit water intake pressure P _IRatio be 0.8, then water body infinitesimal pressure energy component acting can be expressed as 0.2P _IV _W, if, equal former water intake pressure P for the hydraulic pressure hypothesis of pressure diversion conduit through the pressurization device re-injection to after this increase tail water supercharging system of electric substation _I, i.e. the current pressure P that is increased through pressurization device pressurization _ABe 0.2P _I, in the case, the acting of water body infinitesimal pressure energy component can be expressed as 0.4P _IV _W, compare original pressure energy component acting and be doubled, hence one can see that, increases the tail water supercharging system and can increase exerting oneself of water power plant, improves the water power plant generating efficiency.

For new unit, when design, need only balance technology and economic effect, the draft tube structure is transformed and increased by one overlap the tail water supercharging system, just can reach the purpose that improves the water power plant power benefit.The k that the divergent shaped draft tube water outlet aperture is designed to the pressure diversion conduit bore doubly just can make the divergent shaped draft tube water velocity reduce 1/k.Reducing of divergent shaped draft tube water velocity just can increase the difference of pressure diversion conduit and divergent shaped draft tube water velocity, thereby makes that bigger water flow dynamic energy component is converted into electric energy; Increase the tail water supercharging system, just can realize the growth that the pressure energy component is done work, increase the hydraulic generator unit and exert oneself, improve water power plant waterpower utilization rate and generating efficiency.

And,, increase by a cover pressurization device at draft tube as long as existing draft tube is carried out structure and technologic technical innovation for old unit, just can realize technique effect of the present invention.

Claims (4)

1, the water power plant efficient electric power generation method is characterized in that, the draft tube caliber is greater than the pressure diversion conduit caliber.

2, water power plant efficient power generation system comprises reservoir, pressure diversion conduit, water turbine, generator, draft tube, it is characterized in that, the draft tube caliber is greater than the pressure diversion conduit caliber.

3, hydropower station tail water supercharging system comprises connecting tube, supercharging device, pressure inlet, it is characterized in that, the draft tube low-pressure water is annotated back pressure power aqueduct through pressurization device pressurization back.

4, hydropower station tail water supercharging as claimed in claim 3 system is characterized in that, annotates back pressure power aqueduct water flow pressure greater than the draft tube water flow pressure.

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