CN209195590U - Turbine blade and solar chimney electricity generation system - Google Patents
Turbine blade and solar chimney electricity generation system Download PDFInfo
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- CN209195590U CN209195590U CN201821898647.0U CN201821898647U CN209195590U CN 209195590 U CN209195590 U CN 209195590U CN 201821898647 U CN201821898647 U CN 201821898647U CN 209195590 U CN209195590 U CN 209195590U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/70—Wind energy
- Y02E10/72—Wind turbines with rotation axis in wind direction
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/70—Wind energy
- Y02E10/728—Onshore wind turbines
Abstract
The utility model discloses turbine blade solar chimney electricity generation system, and turbine blade is NACA2408 aerofoil profile, and angle of attack value is 6-8 °, and wing chord of the maximum curved surface 2.0% 40.6%, diameter D is 0.12m；Wing chord of the maximum gauge 8.01% 30.1%.Solar chimney electricity generation system, including turbine, connecting bracket, turbogenerator and chimney entrance pedestal with above-mentioned solar chimney electricity generation system blade.By Airfoil Design and CST aerofoil optimization method, design optimization is suitable for the turbine blade of solar chimney electricity generation system, provides new approaches for turbine blade layout.
Description
Technical field
The utility model relates to solar energy generation technology fields.Specifically a kind of turbine blade and solar chimney
Electricity generation system.
Background technique
Turbine is one of important component of system in solar chimney electricity generation system, and turbine blade is turbine
Important component, the air dynamic behaviour of turbine blade shows different, and the efficiency and economy of turbine are different.Whirlpool
In thermal-arrest canopy exit by the hot air acting with certain speed, active force difference suffered by upper and lower surface generates turbine blade
Lift pushes impeller to rotate.The rotation of turbine wheel fills the kinetic energy of hot-air in thermal-arrest canopy by generator drive gear
It sets, is converted to electric energy, complete power generation process.Although having carried out some researchs to turbine blade in the prior art, these
Turbine blade can not be suitable for all regions, and system performance needs to be further increased.
Utility model content
For this purpose, the technical problem to be solved by the utility model is to provide one kind can greatly improve turbine output work
Rate, the turbine blade suitable for Hohhot district and solar chimney electricity generation system.
In order to solve the above technical problems, the utility model provides the following technical solutions: turbine blade, solar chimney into
Rated wind speed at mouthful is 3.0-4.0m/s, and the reynolds number range in thermal-arrest canopy exit is 2.7 × 104；Blade is NACA2408
Aerofoil profile, angle of attack value are 6-8 °, and wing chord of the maximum curved surface 2.0% 40.6%, diameter D is 0.12m；Maximum gauge 8.01% exists
30.1% wing chord.Turbine blade layout method includes the following steps: that (A) determines the specified wind of solar chimney entrance
Speed；(B) turbine blade aerofoil profile type selecting；(C) turbine blade aerofoil profile numerical simulation of optimum；(D) turbine blade layout is determined
Basic parameter；(E) aerofoil profile data are obtained in Profili software, obtain aerofoil profile figure after synthesizing coordinate points；According to each section string
Long scaling obtains aerofoil section figure in CAD, is imported into SolidWorks software after amendment, obtains blade three-dimensional
Scheme and 3D printing goes out blade material object.Solar chimney electricity generation system, including with above-mentioned solar chimney electricity generation system blade
Turbine, connecting bracket, turbogenerator and chimney entrance pedestal.
Solar chimney electricity generation system, including the use of above-mentioned turbine blade, connecting bracket, turbogenerator and chimney
Entrance pedestal, the chimney entrance pedestal are made of lower cylindrical drum, intermediate frustum cone cylinder and upper cylindrical drum, the intermediate frustum cone cylinder
Top and bottom end are fixedly connected with the upper cylindrical drum and the lower cylindrical drum respectively, and the intermediate frustum cone cylinder top is interior
Diameter and outer diameter are equal with the internal diameter of the upper cylindrical drum and outer diameter, and the internal diameter and outer diameter of the intermediate frustum cone cylinder bottom end are and institute
Internal diameter and the outer diameter for stating lower cylindrical drum are equal；The connecting bracket is made of motor installation cylindrical drum, connecting rod and clinch, institute
State connecting rod one end and the motor installation cylindrical drum is fixedly connected, the other end is fixedly connected with the clinch and the company
The axis ventilation hole parallel with the motor installation axis of cylindrical drum is offered on extension bar, the turbogenerator is mounted on institute
It states in motor installation cylindrical drum, arc overlap joint slot is provided on the clinch, the connecting bracket is overlapped by the arc
Slot is mounted in the upper cylindrical drum, and the power intake of the axis of the turbine blade and the turbogenerator, which drives, to be connected
It connects.
Lower cylindrical drum φ 135mm, high 85mm；The high 54mm of intermediate frustum cone cylinder；Upper cylindrical drum φ 113mm,
High 50mm.
The technical solution of the utility model achieves following beneficial technical effect: the utility model, which passes through, determines solar energy
Chimney generator turbine blade basic parameter calculates turbine blade aerofoil profile Choosing Type Analysis using Profili software, choosing
Select the best aerofoil profile of matching solar chimney electricity generation system.And by CST aerofoil optimization method to selection aerofoil profile carry out further into
Row optimization design and calculation of aerodynamic characteristics.The optimal wind energy utilization rate for improving turbine blade, tests by performance test, reaches
Design requirement.By Airfoil Design and CST aerofoil optimization method, design optimization is suitable for the turbine of solar chimney electricity generation system
Machine blade optimizes calculating to improve turbine blade wind energy utilization, also provides new think of for turbine blade layout
Road.
Detailed description of the invention
The NACA2408 aerofoil section figure of Fig. 1 the utility model solar chimney electricity generation system turbine blade；
Lift coefficient and resistance under the different Reynolds number of Fig. 2 the utility model solar chimney electricity generation system turbine blade
Index variation profiles；Lift resistance ratio under the different Reynolds number of Fig. 3 the utility model solar chimney electricity generation system turbine blade
Change curve；The lift coefficient and resistance of the different angles of attack of Fig. 4 the utility model solar chimney electricity generation system turbine blade
Index variation profiles；The lift coefficient of the different angles of attack of Fig. 5 the utility model solar chimney electricity generation system turbine blade with
Resistance coefficient change curve；The aerofoil profile figure of Fig. 6 the utility model solar chimney electricity generation system turbine blade；Fig. 7 sheet
The NACA2408 aerofoil profile figure of utility model solar chimney electricity generation system turbine blade；Fig. 8 the utility model solar energy
The 12 rank fitting result chart of NACA2408 aerofoil profile of chimney generation system Turbo machine blade；Fig. 9 a- Fig. 9 b the utility model solar energy
Aerofoil profile comparative analysis before and after the Xfoil optimization processing of chimney generation system Turbo machine blade；Figure 10 the utility model solar energy cigarette
The aerofoil profile NACA2408 Airfoil polar curve of chimney electricity generation system turbine blade；The power generation of Figure 11 a the utility model solar chimney
System Turbo machine blade in Re=2.7 × 104When C1Curve；Figure 11 b the utility model solar chimney electricity generation system turbine
Machine blade in Re=2.7 × 104When CdCurve；Figure 12 a the utility model solar chimney electricity generation system turbine blade
Lift resistance ratio under the different angles of attack；Under the different angles of attack of Figure 12 b the utility model solar chimney electricity generation system turbine blade
Pitching moment coefficient；Chord length comparison before and after the amendment of Figure 13 the utility model solar chimney electricity generation system turbine blade；Figure
The turbine blade figure of 14 the utility model solar chimney electricity generation system turbine blades；Figure 15 chimney entrance pedestal；Figure 16
Chimney entrance pedestal and turbine connecting bracket；The turbine of Figure 17 the utility model solar chimney electricity generation system turbine is electromechanical
Machine connection frame installation diagram；The turbine motor connection frame of Figure 18 the utility model solar chimney electricity generation system turbine assembles
Figure；The turbogenerator chimney base installation diagram of Figure 19 the utility model solar chimney electricity generation system turbine；This reality of Figure 20
With the turbine energy generating system test schematic of new type solar energy chimney generation system Turbo machine；Figure 21 the utility model solar energy
Chimney generation system Turbo machine turbine peak power output curve under direct current galvanic electricity machine；Figure 22 the utility model solar energy cigarette
Chimney electricity generation system turbine turbine peak power output curve under alternating current generator；Figure 23 a the utility model solar chimney
Wind speed of electricity generation system turbine under the conditions of direct current generator and alternating current generator and turbine peak power output curve；Figure 23 b
The utility model solar chimney electricity generation system turbine turbine output power curve graph in full wind speed range, wherein wind speed
Alternating current generator is used lower than 2.5m/s, is higher than 2.5 meters and uses direct current generator；Figure 24 the utility model solar chimney power generation system
System turbine turbine Maximun power coefficient performance plot under direct current generator；Figure 25 the utility model solar chimney electricity generation system
Turbine turbine Maximun power coefficient performance plot under alternating current generator；Figure 26 a the utility model solar chimney electricity generation system
The power coefficient curved line relation of wind speed and turbine of the turbine under the conditions of direct current generator and alternating current generator；Figure 26 b sheet is practical
New type solar energy chimney generation system Turbo machine under the conditions of direct current generator and alternating current generator full wind speed range in 0.8m/s~8m/
S, the power coefficient variation of turbine；Figure 27 solar chimney entrance temperature, speed change curves；Hot gas before Figure 28 turbine
Flow velocity degree and output power curve；Figure 29 output power measured value and model calculation value curve；Figure 30 output power Experimental comparison
Curve；Figure 31 thermal-arrest canopy collecting efficiency；Figure 32 solar chimney efficiency；Figure 33 turbogenerator generating efficiency；Figure 34 solar energy
Chimney generation system effectiveness.
Specific embodiment
1. turbine blade layout
By the Aerodynamics of foline, selected using the Airfoil Design that special designing software Profili carries out blade
Type and analysis obtain the relevant parameter on airfoil surface: pressure distribution, lift resistance ratio etc., to obtain turbine maximum utilization efficiency.
Selected aerofoil profile is optimized using CST aerofoil optimization method, improves turbine efficiency.Selected aerofoil profile is designed
It determines the work wind speed and electrical power of turbine blade, calculates turbine rotor diameter, determine the tip-speed ratio of blade, select turbine
Machine lobe numbers determine vane airfoil profile, and determining each foline chord length and established angle etc..
The determination of 1.1 turbine rated wind speeds: unstable aerodynamics is to cause turbine blade failure unstable
The control of the principal element of load, turbine can smaller unfavorable load, the determination of turbine wind speed be effectively to know not
How constant wind, which to reach wind wheel, how to influence turbine generates electricity.If the wind of solar chimney entrance can not be fine
Prediction, the good blade of aeroperformance can not be accurately designed during turbine blade layout.It is thus determined that solar energy
The wind speed of chimney entrance is very important the design optimization of turbine blade, this is also the pass of turbine blade layout
Key condition.Since turbine is in the three-dimensional flow fields environment changed over time, rotation of the wind speed in the impeller of entire turbine
It is distributed different in plane, while by turbulent flow, fixed bracket, inner wall of stack be coarse etc., factors are influenced, and need to establish effective
Solar chimney entrance wind speed prediction model, wherein wind speed prediction model by pneumatic torque estimation and estimate the meter of air speed value
Calculate two parts composition.
1.1.1, the estimation of pneumatic torque: Kalman filtering algorithm can effective estimated state, can be derived that system
The optimal State Estimation of true environment, the available Space admittance of Markov process are as follows:
TtIt is the time constant of pneumatic torque, TaIt is pneumatic torque, ε is the normal distribution noise that variance is R1.
The transmission system equation of turbine generation unit are as follows:
In formula:
Wherein TaFor pneumatic torque, JtFor turbogenerator combination rotary inertia,Angular acceleration, TgGenerator turns
Square, TfIt is axis and sealing element torque, Nm, JgIt is the rotary inertia of generator, kgm2, JrIt is the rotary inertia of rotor, kg
m2, ngGenerator speed rad/min, TeElectronic torque, Nm.
Turbine generation unit uses two input signal vectors: wind speed and command torque generate two output signal vectors:
Aerodynamic moment and revolving speed, the dynamics available mode spatial model for linearizing turbine set indicate.Obtain transmission chain state and defeated
Equation out:
In formula:
In formulaIt is transmission chain state, X is system mode, and A is sytem matrix, and U represents the torque instruction signal of generator,
B is matrix [- 1/Jt 0]-1, y is output quantity, and H is matrix [1 0], and matrix B influences state dynamic, ktIt is constant, WrIt is wind wheel rotation
Tarnsition velocity, TaIt is pneumatic torque, JtFor the rotary inertia of turbogenerator combination.Chimney entrance considers solar chimney hair
The noise and measurement noise of electric system, selecting the sampling period is Ts, carries out discretization to dynamics state model, obtains turbine set
Kalman's discrete model of transmission chain, it may be assumed that
X (k+1) is the system mode at K+1 moment, A (k+1, k)=I+ATs, I is quadravalence unit matrix, and A is system square
Battle array, A (k+1, k) are the state-transition matrix at K moment to K+1 moment；X (k) is state vector；B (k+1, k)=BTs, U (k) is
Nonrandom control sequence, B are matrix [- 1/Jt 0]-1；W (k) is system noise, and Z (k+1) is observation vector, and H (k+1) is to see
Matrix is surveyed, V (k) is measurement noise, and k is the time；TsTo select the sampling period；
Assuming that W and V is system noise and measurement noise, W and V is zero mean Gaussian white noise, probability density in systems
Function are as follows:
P (W)~N (0, Q), P (V)~N (0, R)
Wherein: Q is the covariance matrix of system noise, and R is the covariance matrix for measuring noise, and both W and V are unit
Battle array Q and R is constant matrix, with system mode X and sampling period TsUncorrelated, P matrix is the error moments of the covariance of estimated state
Battle array, O is value of zero, and N is normal distribution.
1.1.2, the calculating of air speed value: anemobiagraph is mounted on solar chimney import in solar chimney electricity generation system
Place, because anemobiagraph, which will be rotated the wake flow generated by wind wheel, to be influenced, anemobiagraph can not highly precisely measure the sun
The size of the wind speed of energy chimney entrance.The utility model based on the estimated value of turbine wind speed round and pneumatic torque,
The size of effective wind speed is estimated using Newton-Raphson method.
Pneumatic torque expression formula:In formula:
ρ is density, and R is blade wing chord diameter, and V is wind speed；βoptIt is optimum tip-speed ratio；λ is tip speed ratio；CpIt is wind
It can usage factor.
Estimate wind speed expression formula:
In formula:
F (n)=Ta(7)；
Air speed value is wherein estimated under the optimal solution of ν, J (t, n) is rotary inertia,It is torque estimated value, f (n) is
Objective function, TaIt is pneumatic torque, I (t, n) is pneumatic torque difference,It is pneumatic torque estimated value, n is infinite number.
Estimate wind speed recursive expression are as follows:
In formula:
In formula: n is ordinal number,It is average value, HnIt is variation coefficient, gnIt is variable function,It is Attitude rate estimator value.
The inaccuracy of solar chimney measurement wind speed is avoided using the air speed value that Newton-Raphson method obtains, together
When also very accurately reflect the actual wind speed value of solar chimney entrance.It is combined by Newton-Raphson method to collection
Hot systems experiment and the comparative analysis of collecting system numerical simulation data and Hohhot district meteorological data obtain solar energy cigarette
The mean wind speed of chimney entrance is 3.8m/s.
1.2 turbine blade aerofoil profile type selectings: the selection of turbine blade aerofoil profile and turbine efficiency are closely related, this is practical
It is novel according to solar chimney collecting system previous experiments and numerical simulation result from thermal-arrest canopy exit Reynolds number and thermal-arrest canopy
Exit air velocity [being equal to solar chimney entrance wind speed] considers, analyzes software Pro fili in conjunction with professional Airfoil Design
Carry out aerofoil profile selection.When choosing aerofoil profile data, consider that choose Reynolds number is close determining Reynolds with Reynolds number when experiment test
Number.Aerofoil profile choosing is carried out then according to the maximum principle of lift resistance ratio (Cl/Cd) simultaneously.Comprehensive analysis considers to choose NACA2408 aerofoil profile.Root
According to the aerofoil profile in different Reynolds number Re number, lift coefficient (Cl) corresponding to the different angles of attack (Alfa), resistance coefficient (Cd) are determined
Maximum lift-drag ratio, it is final to determine optimal attack angle value, (Cm pitching moment coefficient) as shown in table 1.
Lift resistance ratio maximum value under the 1 NACA2408 difference angle of attack of table
| Alfa | Re(×104) | Cl | Cd | Cl/Cd | Cm |
| -2.0 | 2.7 | -0.0996 | 0.0213 | -4.6761 | -0.0319 |
| -1.0 | 2.7 | -0.0170 | 0.0215 | -0.7907 | -0.0289 |
| 0.0 | 2.7 | 0.0660 | 0.0224 | 2.9464 | -0.0265 |
| 1.0 | 2.7 | 0.1462 | 0.0240 | 6.0917 | -0.0249 |
| 2.0 | 2.7 | 0.2209 | 0.0266 | 8.3045 | -0.0244 |
| 3.0 | 2.7 | 0.2889 | 0.0304 | 9.5033 | -0.0253 |
| 4.0 | 2.7 | 0.3504 | 0.0357 | 9.8151 | -0.0276 |
| 5.0 | 2.7 | 0.4754 | 0.0445 | 10.6831 | -0.0446 |
| 7.0 | 2.7 | 0.9214 | 0.0457 | 20.1619 | -0.0306 |
| 8.0 | 2.7 | 0.9591 | 0.0625 | 15.3456 | -0.0252 |
| 9.0 | 2.7 | 0.9247 | 0.0866 | 10.6778 | -0.0278 |
| 10.0 | 2.7 | 0.8608 | 0.1169 | 7.3636 | -0.0440 |
| 11.0 | 2.7 | 0.7525 | 0.1487 | 5.0605 | -0.0801 |
| 12.0 | 2.7 | 0.7641 | 0.1636 | 4.6705 | -0.0812 |
| 13.0 | 2.7 | 0.8040 | 0.1850 | 4.3459 | -0.0835 |
Systematic selection NACA2408 aerofoil profile is managed by the aerofoil profile in Profili software, determines the air foil shape.Selection is slightly
Thick NACA2408 aerofoil profile, maximum opposite camber is 2%, and position is at 41.2% wing chord of chord length；Maximum relative thickness is
8.01%, at 29.8% wing chord.NACA2408 foline profile diagram is as shown in Figure 1.In the movement of turbine blade, pass through
Dust suppression by spraying --- Reynolds number, which characterizes viscous force, to be influenced.So choosing lift system as far as possible in the design of turbine blade
Number changes lesser situation with the variation change of Reynolds number to determine lift coefficient.From lift under such as Fig. 2 different Reynolds number
Coefficient and drag-coefficient curve figure are determined in thermal-arrest canopy exit reynolds number range in Re=2.7 × 104When, NACA2408
Aerofoil profile maximum lift coefficient is in lift coefficient ClNear=0.9214, the corresponding angle of attack is between 6~8 °, the thunder near the point
Influence of the variation of promise number to the maximum lift coefficient and optimal attack angle of the aerofoil profile is smaller, and Reynolds number is transported close to blade at this moment
Row Re number.Therefore it can determine in Re=2.7 × 104When turbine blade run under real work operating condition.Utilize the Profili wing
Type aerodynamic Simulation software carries out calculation of aerodynamic characteristics to 2408 aerofoil profile of NACA, passes through the liter under comparison different Reynolds number
Ratio is hindered with angle of attack variation curved line relation such as Fig. 3, is carried out screening analysis, can be determined in reynolds number Re=2.7 × 104When, with
The variation of Reynolds number, lift coefficient variation is relatively steady, i.e., maximum to turbine blade aerofoil profile with the change of air viscosity
Lift coefficient influences lower.Therefore select reynolds number Re=2.7 × 104The corresponding point of corresponding maximum lift-drag ratio is design
Point, the angle of attack for choosing the point is the design angle of attack of blade, as shown in Figure 3.As shown in table 1, optimal attack angle α=7 ° of aerofoil profile are selected,
Corresponding lift coefficient Cl=0.9214, resistance coefficient Cd=0.00457, lift resistance ratio Cl/Cd=20.1619.
1.3 NACA2408 aerofoil profile numerical simulation of optimum: turbine blade the 75% of acquired energy is from aerodynamic energy
It is provided by the front half section of blade.Since the swept area of blade is with square variation of radius, blade working efficiency is also and half
Diameter is related, and the smaller efficiency of radius is lower；Meanwhile radius is small, tip-speed ratio is also small, therefore wind energy utilization of the root of blade to wind energy conversion system
Coefficient CPInfluence it is also smaller.Due to smaller in blade dimensions, geometric dimension is distorted at blade tip, and the capture for reducing power is made
With.To optimize vane airfoil profile parameter, the utility model is selected general in recent years based on CST (Class function/Shape
Function Transformation) parametric method of type function/class function transformation indicates aerofoil profile and uses CST type letter
Number is used as design variable, carries out Airfoil Design and calculation of aerodynamic characteristics to turbine blade by least square method.
1.3.1 CST aerofoil profile parameter optimization method: Airfoil Design is the significant process of turbine blade layout, aerofoil profile parametrization
The selection of method affects the reasonability of selected Airfoil Design method.General three-dimensional geometric shapes can basic configuration
To indicate, type function and class function can describe the distribution of object basic configuration and basic configuration for distribution.Pass through this letter of CST
Single multipurpose and powerful method, define three-dimensional geometry object in design space by class function and type function,
It introduces class function (Class function) and defines airfoil geometry shape type, determine a family of aerofoil sections.With type function (Shape
Function) come, determine a specific aerofoil profile in aerofoil profile represented by class function, type function determines class function substantially outer
Shape is modified, and generates the geometric shape of design modification.By the least square method the Fitting Calculation to aerofoil profile, expression type letter is obtained
The empirical data value range of several Bernstein polynomial orders.CST Parameter Switch optimization method parameter has clear geometry
Meaning, and control parameter is few, applied widely, accuracy is higher.This method can be not only used for the parametrization of aerofoil profile coordinate,
Also there is good application prospect in terms of the aerodynamic optimization of dimensional airfoil and three-dimensional wing etc..
1.3.2 CST aerofoil optimization method: as the geometric representation formula of Fig. 6, general aerofoil profile can indicate are as follows:
In formula: ψ=x/c, ξ=z/c, ξT=△ ξTE/c；For leading edge；1- ψ is empennage；ψ·ξTFor empennage thickness；For the geometry general purpose function of leading edge and empennage, c is chord length；Z is the z-axis coordinate of aerofoil profile, and N is aerofoil profile class function
Control parameter, x is the x-axis coordinate for aerofoil profile, i 0,1,2 ... n；AiIt is Bernstein polynomial, ζTIt is relative value, ζTEIt is
Airfoil trailing edge thickness.
The type function of general aerofoil profile is defined by formula 12:
Aerofoil profile class function are as follows:
In formula: N1, N2For the control parameter of aerofoil profile class function.
The utility model chooses NACA2408 airfoil trailing edge with a thickness of zero, i.e. ξT=0, upper and lower surface curve generic representation
Are as follows:
Class function in formula are as follows:
In formula:
Type function S (ψ) indicates aerofoil profile leading edge to the curve shape between rear, expression are as follows:
In formula:N indicates the order of Bernstein polynomial,It is multinomial for Bornstein
Formula weight coefficient collection.
For CST aerofoil profile parameterized procedure: 1, determining class functionParameter N1, N2.Different airfoil profiles are corresponding different
N1, N2Value.For rounded leading edge race aerofoil profile N1=0.5, N2=1.0.2, the control parameter of type function S (ψ) is determined.Here make
With the Bernstein multinomial with weight coefficient, it may be assumed that
Wherein:
If:
Have
Type function S (ψ) is expressed as by weighting:
There is n+1 Bornstein coefficient A in type functioni, it is necessary to n+1 control point coordinates are obtained, are controlled by n+1
Point coordinate
Equation is established, is had:
Since NACA2408 airfoil trailing edge is with a thickness of 0, above formula simplifies are as follows:
Pass through the polynomial weight coefficient of the available Bernstein of (24) solve system of equation
1.3.3 CST aerofoil optimization method: according to the parameter of NACA2408 aerofoil profile: maximum opposite camber is 2.0%, position
It sets at 41.2% wing chord of chord length, maximum relative thickness 8.01%, position are at 29.8% wing chord of chord length；From
Profili software exports related aerofoil profile numerical value such as table 3 and calculates the coordinate point value of aerofoil profile by origin software, draws aerofoil profile song
Line such as Fig. 7.
3 NACA2408 upper and lower surface coordinate value of table
| Upper surface X | Upper surface Y | Lower surface X | Lower surface Y |
| 0 | 0 | 0 | 0 |
| 0.0121 | 0.0140 | 0.0104 | -0.0098 |
| 0.0540 | 0.0306 | 0.0565 | -0.0194 |
| 0.1012 | 0.0406 | 0.1059 | -0.0225 |
| 0.1507 | 0.0481 | 0.1576 | -0.0234 |
| 0.2018 | 0.0535 | 0.2013 | -0.0232 |
| 0.3050 | 0.0589 | 0.3066 | -0.0211 |
| 0.4005 | 0.0587 | 0.4037 | -0.0186 |
| 0.5054 | 0.0544 | 0.5005 | -0.0158 |
| 0.6015 | 0.0481 | 0.6061 | -0.0124 |
| 0.7064 | 0.0387 | 0.7028 | -0.0093 |
| 0.7586 | 0.0332 | 0.7555 | -0.0077 |
| 0.8018 | 0.0283 | 0.8082 | -0.0061 |
| 0.8540 | 0.0218 | 0.8522 | -0.0048 |
| 0.9060 | 0.0148 | 0.9050 | -0.0034 |
| 100 | 0 | 100 | 0 |
Using the coordinate points of table 3, control point coordinates are obtained using interpolation method, and according in CST parametric method
The polynomial order of Bernstein and formula 23 calculate CST control parameter, and upper lower aerofoil is multinomial using 5 rank Bernstein
Formula, 6 groups of control point coordinate value, is shown in Table 4.It brings coordinate value of control point into formula 22 and obtains aerofoil profile NACA2408 upper and lower surface CST
Parameter, being shown in Table 5, Fig. 8 is using CST parametric method to NACA2408 aerofoil profile fitting result chart.
4 NACA2408 aerofoil profile control point coordinates of table
5 NACA2408 aerofoil profile control point coordinates of table
| Upper surface parameter | 0.29527 | 0.2506 | 0.34013 | 0.22635 | 0.28921 | 0.05174 |
| Sub-surface parameter | -0.22262 | -0.21296 | -0.12822 | -0.21843 | -0.09434 | -0.03265 |
Fig. 8 illustrates the fitting effect of aerofoil profile NACA2408.True Curve of wing is exported by Profili software in figure
The Curve of wing figure that is drawn in origin software of NACA2408 aerofoil profile coordinate points.CST12 rank fitting result curve is in figure
NACA2408 aerofoil profile using CST method aerofoil profile is optimized after aerofoil profile and the true Curve of wing of NACA2408 comparison.It is logical
It crosses CST parametric method and parametrization decomposition is carried out to aerofoil profile, less parameter can be used accurately to indicate an aerofoil profile, make
It can achieve higher precision, as shown in Figure 8, CST with the type function of 5 rank Bernstein polynomial repressentation aerofoil profile NACA2408
Parametrization aerofoil profile and true aerofoil profiles coincide substantially.
After being optimized by CST parametric method to blade, the leading-edge radius of aerofoil profile, maximum gauge and maximum curved surface
Position all changes.Therefore processing optimization is re-started to blade by the Xfoil setting in Profili software.Processing
Front and back aerofoil profile comparison diagram is as shown in Figure 9.
1.4 turbine blade layout basic parameters
1, turbine output P=0.1250W；2, arrives stream wind speed: V1=3.5m/s；
3, turbine electromechanical efficiency: η1η2=0.85；4, atmospheric density: ρ50°=1.128kg/m3；
5, turbine blade diameter:
D=0.12m, CPFor Maximun power coefficient (power coefficient).
6, tip-speed ratio: the ratio between tip speed and design wind speed of turbine wind wheel.
Choose blade tip-speed ratio λ0=6, blade tip wind speed is V=λ0×V1=48m/s；
Wind wheel angular speed
7, due to three blade turbine stable output power, three-vane turbine, B=3 number of blade B: are chosen.
8, impeller solidity σ=0.07；9, turbine blade is divided into 10 sections, each profile intervals 0.1R, each section
Tip-speed ratio be shown in Table A.10, NACA2408 aerofoil profile parameter curve.It can be obtained in for reynolds number Re=26887, Profili software
Maximum lift-drag ratio CL/Cd=20.1619, wherein CL=0.9214, Cd=0.0457, angle of attack=7 °.It can be with by parameter input
Figure 10 aerofoil profile NACA2408Airfoil polar curve is obtained, Figure 11 a and Figure 11 b are Re=2.7 × 104C under the Shi Butong angle of attacklWith
Cd, lift resistance ratio, pitching moment coefficient under Figure 12 a and Figure 12 b difference angle of attack.
11, it determines the form parameter N of each section, and calculates chord length λ0=6,
Wherein λ0=3.26 can obtain chord length formula according to formula:
In formula: r --- blade is divided into 10 sections, the radius value at each section, referring to table 2.λ --- at each section
Tip-speed ratio, referring to Table A.It calculates gained chord length and is shown in Table A.
12, leaf chord length is corrected: obtain ideal blade shape and blade angle, but the installation of this ideal blade
Angle is along span of foil in nonlinear change.Therefore, it is necessary to the chord lengths and established angle linearization process to ideal blade.For
Be adapted to the utility model solar chimney power generation test system turbine blade for, due to entire turbine radius compared with
Small, radius only has 0.06m, and hub diameter is smaller, leaf chord length in order to adapt to the size of wheel hub, chord length after amendment at blade root compared with
It is short.According to the practical flow field situation of solar chimney power generation test system, blade design amendment keeps the aeroperformance of blade good
Good section.The second half section aeroperformance of turbine blade is good.Chord length corrects the actual state according to turbine, considers the jail of blade
Solidity and stability are modified from blade root.Figure 13 is leaf chord length amendment front and back comparison.Revised chord length such as Figure 13, string
Long amendment front and back, which is compared, is shown in Table 2.
2 chord length of table amendment front and back comparison
13, determine the established angle of aerofoil profile at each section: amendment torsional angle is in view of lift resistance ratio is to axially and tangentially interfering the factor
Influence is smaller, disregards the influence of resistance when designing turbine blade aerodynamic configuration, but it is available such as to consider taper loss
Lower mathematical model.
A (1-aF)=b (1+b) λ2(27)；
F is blade tip loss coefficient, and a is the Axial Interference factor, and b is the radial interference factor；
When considering blade tip loss, local power coefficient are as follows:
The amendment torsional angle at each section is calculated using Wilson method using MATLAb software, the independent variable in equation
A, b is iterated operation after assigning initial value automatically, maximum (minimum) value and its corresponding a, b value until obtaining objective function.Its
Middle initial value formula are as follows:
B=10/ λ0·e12r/R(33)；
A=λ0/2000+0.027λ0-0.038 (34)；
Optimum optimization function passes through two M file stored target functions of creation and conditional function, respectively objfun function
With confun function.By calling in main program, optimum optimization function acquires interference factor a, b and blade tip coefficient F is finally defeated
Torsional angle value out.Because it is contemplated that the influence of root connection wheel hub, thus from 20% calculate torsional angle, calculated result is shown in Table A.
Each sectional parameter of Table A vane airfoil profile
To sum up, NACA2408 aerofoil profile data are obtained in Profili software, obtain aerofoil profile figure after synthesizing coordinate points.According to
The scaling of each section chord length obtains aerofoil section figure in CAD, imported into SolidWorks software, obtain after amendment
Go out blade material object, such as Figure 14 to blade three-dimensional figure and 3D printing.
The assembly of 2.5 turbine blades: selecting two kinds of motors, and basic parameter is shown in Table 5.
5 turbine alternating current generator parameter list of table
6 turbine direct current generator parameter list of table
Solar chimney electricity generation system utilizes turbine blade 1, connecting bracket 2, turbogenerator 3 and chimney entrance bottom
Seat 4, the chimney entrance pedestal 4 are made of lower cylindrical drum 41, intermediate frustum cone cylinder 42 and upper cylindrical drum 43, the intermediate frustum cone cylinder
42 top and bottom end are fixedly connected with the upper cylindrical drum 43 and the lower cylindrical drum 41 respectively, and the intermediate frustum cone cylinder
The internal diameter and outer diameter on 42 tops are equal with the internal diameter of the upper cylindrical drum 43 and outer diameter, intermediate 42 bottom end of frustum cone cylinder it is interior
Diameter and outer diameter are equal with the internal diameter of the lower cylindrical drum 41 and outer diameter；The connecting bracket 2 is installed cylindrical drum 21 by motor, is connected
Extension bar 22 and clinch 23 form, one end of the connecting rod 22 and the motor install cylindrical drum 21 be fixedly connected, the other end
The axis of axis and motor installation cylindrical drum 21 is fixedly connected with and offered in the connecting rod 22 with the clinch 23
Parallel ventilation hole 23, the turbogenerator 3 are mounted in the motor installation cylindrical drum 21, are arranged on the clinch 23
There is arc to overlap slot 231, the connecting bracket 2 overlaps slot 231 by the arc and is mounted in the upper cylindrical drum 43, described
The power intake of the axis of turbine blade 1 and the turbogenerator 3 is drivingly connected.
Chimney base design carries out calculating design, chimney base size: bottom according to the actual ratio of solar chimney import
Seat outer diameter φ 222mm, screw hole φ 10mm, φ 135mm, the high 85mm of lower cylindrical drum, the high 54mm of intermediate frustum cone cylinder, upper cylindrical drum
φ 113mm, high 50mm.Bracket, fixed turbine machine are added above pedestal.Pedestal such as Figure 15.In SolidWorks software
Forging processing is carried out after the completion of design obtains material object as shown in figure 15.
Turbine and chimney base using connection frame overlap joint, the purpose of design of connection frame be reduce to the greatest extent turbine too
The wind energy loss of positive energy chimney entrance.Connection frame size are as follows: connection chimney base interface end outer diameter φ 124.6mm, internal diameter φ
113mm, thickness 1.5mm, the high 15mm of connection frame, dress motor cylinder φ 21mm, thickness 1.5mm.Connection frame is shown in Figure 16.And carry out 3D
The connection frame that printing is obtained such as Figure 16 is in kind.
Connection frame is fixed on chimney base, turbogenerator is mounted on above connection frame, in SolidWorks software
In assembled.Obtain installation diagram as shown in figure 17.Each component is assembled.Assembling figure such as Figure 18.By turbine generation
Machine is connected to solar chimney pedestal with connection frame, obtains the installation diagram of the three-dimensional modeling such as Figure 19, turbogenerator is assembled
It is put on test-bed, carries out the experiment of turbine blade test.
2. turbine blade is tested
Turbogenerator is to convert mechanical energy for the kinetic energy of hot-air, and the equipment of energy is exported in the form of electric energy.Whirlpool
The maximum power turbine that turbine can be such that turbine exports under different air velocitys, the working condition of different tip speed ratios
Peak power output.Since torque can not obtain under turbine operating conditions, can only by experiment measurement turbine output voltage,
It exports electric current, calculate electrical power, then select electric efficiency and transmission efficiency.Obtain turbine shaft power and output power.It is logical
Cross the shaft power that formula (35) calculates turbine.
In formula: P---- turbine shaft power (W)；η1----transmission efficiency；η2----electric efficiency；U---- turbine is defeated
Voltage (V) out；R---- load resistance (Ω).Selected dc generator is tested, load is steady, and dynamotor is continuously run, this
It is 0.9 that generator drive gear efficiency is selected in utility model.
By the measurement to turbine wind speed υ (m/s) and the revolving speed n (r/min) of turbine wheel, turbine can be calculated
Blade tip-speed ratio:
In formula: R --- turbine blade radius.
The power coefficient C of turbineP: CP=2P/ ρ s υ3(37)；
In formula: s --- wind wheel sweeping area (m2)；ρ-atmospheric density (kg/m3)。
2.1 turbine threshold wind velocity test experiments
One, test equipment
Table B test equipment list
Two, test method
1, using oscilloscope measurement voltage, hot-wire anemometer measures wind speed, and multimeter measures resistance.
2, output voltage U and load resistance are measured, electric work is calculated by changing load under different air velocitys
Rate.It determines electric efficiency and transmission efficiency, calculates turbine output power P.
3, under a stable hot-fluid air velocity, maximum (top) speed n is determined by adjusting slide rheostat, calculates and corresponds to
Tip-speed ratio λ measures the voltage U and resistance R of load, calculates electrical power, determines electric efficiency and transmission efficiency, calculates turbine
Output power P under each tip-speed ratio.Determine the peak power output under every group of difference hot-fluid air velocity, drawing system speed-function
Rate curve graph.
3, turbine energy generating system test wiring diagram is as shown in figure 20: the experiment of turbine unit starting is in turbine
It is tested under unloaded situation, turbine starts low speed revolution wind-tunnel under state windward, adjusts the frequency conversion being connected with wind-tunnel motor
Device changes wind speed, increases or decreases the frequency of frequency converter to adjust wind speed.The wind speed that turbine wind wheel rotates one week is recorded,
Repeat the accuracy that test guarantees measurement.The threshold wind velocity measurement data of direct current generator and alternating current generator is shown in Table 7.
7 threshold wind velocity of table records data
| Number | 1 | 2 | 3 | 4 | 5 |
| Direct current generator starts wind speed (m/s) | 2.50 | 2.51 | 2.49 | 2.50 | 2.50 |
| Alternating current generator threshold wind velocity (m/s) | 0.81 | 0.80 | 0.80 | 0.79 | 0.80 |
The threshold wind velocity average value of turbine are as follows:
The threshold wind velocity of alternating current generator is 0.8m/s, and the threshold wind velocity of direct current generator is 2.5m/s.
2.2 turbine peak power output test experiments: turbine unit is in freely under state windward, is adjusted to each
Air speed value adjusts the size of slide rheostat fluctuating load, power is made to reach maximum value when wind speed is relatively stable, when
The size of voltage resistance and revolving speed under each wind speed of the steady Timing measurement of turbine blade rotation.The threshold wind velocity of direct current generator is
2.5m/s, wind speed test scope be 2.5~8m/s, between wind speed and wind speed between be divided into 0.5m/s.Gained maximum power is with wind speed
Change curve relationship it is as shown in figure 21.As can be seen from the figure increase as wind speed increases turbine output power, starting
Under wind velocity condition, peak power output 0.0073W.The threshold wind velocity of alternating current generator is 0.8m/s, and wind speed test scope is
0.8~6m/s, between wind speed and wind speed between be divided into 0.5m/s.Gained maximum power is shown in Figure 22 with the change curve of wind speed.
Peak power output is 0.00026W under the threshold wind velocity of alternating current generator.
2.3 turbine maximum power output characteristics: in the case where turbine wheel is in freely state windward, starting low speed revolution
Wind-tunnel carries out peak power output attribute testing under the test wind under each stable wind speed.Test wind speed range is 0.8m/s
To 8m/s, wind speed acquires every 0.5m/s and is once adjusted.Test load is adjusted, acquisition is defeated after turbine wheel is stable
Voltage, electric current and calculating output power out.Changed according to turbine output power under the different wind speed of test data drafting with wind speed
Figure.Such as Figure 23 a and Figure 23 b.In carrying out turbine output power testing experiment, the test of turbine output power uses respectively
Alternating current generator and dc generator.Different generator threshold wind velocities are different, and alternating current generator threshold wind velocity is lower, and Figure 23 a is
Wind speed and turbine peak power output curve under the conditions of direct current generator and alternating current generator.Figure 23 b is whirlpool in full wind speed range
Turbine output power curve figure, wherein wind speed uses alternating current generator lower than 2.5m/s, is higher than 2.5 meters and uses direct current generator.Pass through
Power output situation under full blast speed-power output figure reflection wind velocity condition 0.8-8m/s.In identical wind speed known to Figure 23 b
Under the conditions of turbine under direct current generator output power it is larger.Wind speed uses direct current generator after 2.5m/s, can obtain
Higher output power.Figure 23 b wind speed range reflects the turbine maximum output under different wind friction velocities in 0.8m/s~8m/s
Power changing rule.Turbine output power increases as wind speed increases, and the influence of turbine stall is less than wind speed increase pair
The contribution of power.For turbine under rated wind speed, alternating current generator output power is 0.0123W, and direct current generator 3.8m/s power is
0.065W。
2.4 power coefficient characteristics: turbine wind wheel is in freely under state windward, and starting low speed revolution wind-tunnel waits for that wind speed is steady
Each air speed value is measured after fixed.It adjusts slide rheostat and changes test load, output is recorded after turbine is relatively stable
Voltage value, resistance value and maximum power.It is divided into 0.5m/s between the wind speed of two adjacent groups test, wind speed is since threshold wind velocity
2.5m/s~8m/s.Maximun power coefficient C is calculated according to experimental datap, show that turbine-driven generator is direct current generator in difference
The characteristic curve of Maximun power coefficient such as Figure 24 under wind speed.The power coefficient of turbine is most under the wind speed of 4.5m/s as seen from the figure
Greatly, the wind energy using solar chimney entrance of turbine is more at this time, and generating efficiency is bigger.Turbine wind wheel is in freedom
Windward under state, wind speed range is 0.8~6m/s, and adjacent two experiments wind speed test section is 0.5m/s, is surveyed after wind speed is stablized
The output voltage under alternating current generator, resistance value and maximum power value are measured, power coefficient is calculated and obtains under the different wind speed such as Figure 25
Power coefficient curve.The power coefficient of wind speed turbine under the situation of 1m/s is maximum as seen from the figure, utilizes solar chimney
The energy of the thermal current of entrance is more, and generating efficiency is higher.The test of turbine output coefficient feature uses AC and DC
Two kinds of motors, experiment test scope are threshold wind velocity 0.85m/s to 8m/s, and wind speed interval 0.5m/s takes test value, such as Figure 26 a
With Figure 26 b.Figure 26 a is the power coefficient curved line relation of the wind speed and turbine under the conditions of direct current generator and alternating current generator, by scheming
Know that gradually increasing under wind velocity condition, peak value occurs in the power coefficient of turbine for starting since turbine.Direct current generator exists
Emergent power coefficient maximum value when 4.5m/s wind speed, there is peak value under 1m/s wind speed in turbine under the conditions of alternating current generator, and two kinds
State compares under same wind speed, and the turbine output coefficient of direct current generator is more preferable, thus chooses alternating current generator test in 2.5m/
Experiment value under s wind speed, direct current generator are chosen at the experiment value under 2.5m/s wind speed.Figure 26 b is two kinds of full wind speed ranges of motor
In 0.8m/s~8m/s, the power coefficient changing rule of turbine.
2.5 solar chimney electricity generation system output power test experiments
2.5.1 solar chimney entrance air characteristics are tested: mid-June is chosen in the experiment of solar chimney electricity generation system
It was the experiment testing time to mid-July one month.Selection irradiation intensity all day is preferable, and wind speed is lower, black clouds weather condition.With
For the experimental results on July 9th, 2018, data analysis is carried out.16 DEG C~30 DEG C of whole day temperature, testing time 9:30
~18:30, the initial temperature of solar chimney system thermal-arrest canopy entrance are 38.18 DEG C, initial velocity 0.95m/s.It is testing
It is under no wind condition and measures before date experimental provision 10:30, irradiation intensity is gradually increased, thermal-arrest temperature of shed liter
Height, too can the increase of chimney systems chimney entrance wind speed.As shown in Figure 27 whole system at noon 13:30 or so when there is peak
Value, chimney entrance velocity reach 1.182m/s, and temperature is 39.28 DEG C, and ambient temperature is 33.20 DEG C, chimney inlet and outlet temperature
Difference is 6.08 DEG C.Since Hohhot district summer meteorological condition is that the morning is sunny calm, wind speed in afternoon at noon increases.Therefore,
Due to being influenced by weather unstable factor, afternoon, ambient wind velocity increase caused the experimental data of solar chimney electricity generation system to go out
It now fluctuates, afternoon, falling tendency occurred in 14:30 or so, and the temperature of solar chimney entrance is 36.47 DEG C at this time, ambient enviroment
Temperature is 31.39 DEG C, ambient wind velocity 1.1m/s, and it is 5.08 DEG C that chimney, which imports and exports the temperature difference,.Wind speed flows into thermal-arrest canopy, accumulation of heat
The heat loss of layer leads to the reduction of recuperation layer temperature, and internal-external temperature difference reduces, and causes the reduction of solar chimney entrance wind speed.
2.5.2 system output power test result analysis: turbine output power test experiments are alternating current using motor
Machine, measurement is primary per minute for experiment measurement, chooses average value per hour, accurately and stably reflects in different moments difference wind speed
Lower turbine generation power curve characteristic, as shown in figure 28, since thermal-arrest canopy is in stage regenerator, recuperation layer before morning 12:00
Temperature is lower, and thermal-arrest canopy internal-external temperature difference is smaller, and system inner chimney input end wind speed is low, causes turbine output power lower.With
Solar irradiation increase, thermal-arrest canopy recuperation layer temperature increases, and thermal-arrest temperature of shed rises, and system internal-external temperature difference increases, in system
Chimney entrance flow velocity increases, and pushes turbine to do work so that output power rises.System output power in 13:30 or so goes out
Existing peak value, output power reach 0.3617mW.Sine distribution is presented in output power curve, meets theoretical rule.In testDate,
Afternoon ambient wind velocity increases, and occurs peak value again in 15:30 turbine output power, output power reaches 0.4636mW.Occur
The phenomenon is because when extraneous wind speed increases, the air flowing of chimney outlet is affected, so that chimney breast end is born
Pressure, increases the suction force of system.Output power is caused to go out again due to reinforcing suction force and the dual coupling influence of internal-external temperature difference
Existing peak value.
2.5.3 model power and measured power comparative analysis: the conversion of solar chimney electricity generation system energy mainly has three
Point, thermal-arrest canopy converts solar energy into the interior energy of air in thermal-arrest canopy, so that air themperature increases in canopy, in solar chimney
Kinetic energy is converted heat into, is converted the kinetic energy into electrical energy by turbogenerator.The power generation of solar chimney power system model
Power are as follows:
In formula: PR--- turbine generation engine efficiency, W；ηR--- turbine energy transfer efficiency, ηR=0.42；ρm--- cigarette
Chimney bottom air density, ρm=1.093kg/m3；λ --- thermal coefficient, λ=3.4 × 10-2W·(m·K)-1；G --- gravity
Acceleration, g=9.8m/s2；cp--- specific heat at constant pressure, cp=1.005 × 103；α --- convection current average heat transfer coefficient, α=24.3
×10-6m2/s；υ --- kinematic viscosity, υ=16.96 × 10-6m2/s； Ts--- surface temperature in thermal-arrest canopy, K；Ti --- collection
Air themperature in hot canopy, K；Ta --- thermal-arrest canopy entering air temperature, K；R --- chimney radius, r=0.06m；R --- thermal-arrest
Canopy diameter, R=2m；Hc --- chimney height, Hc=1.2m；Hp --- thermal-arrest canopy surrounding clearance height from the ground, Hp=
0.25m。
T in formula 38s、Ti、TaValue is measured value, when available corresponding according to the test temperature numerical value for not having to the time
Between estimation output power value.Model power output only considers the influence of temperature known to formula 38, does not account for ambient wind velocity
It influences.As seen from Figure 29, whole day ambient wind velocity is gradually increased, and wind speed flows into thermal-arrest canopy, as wind speed increase can be taken away
Recuperation layer gathers heat in the thermal-arrest canopy of part, and the heat of accumulation of heat layer surface is caused largely to scatter and disappear, and leads to the reduction of recuperation layer temperature.It makes
It is lower at external pelivimetry temperature difference in collecting system, so that model output power calculating is worth lower, turbine output power measured value
It is higher.
2.5.4 this solar chimney electricity generation system turbine comparative experiments measured power data comparative analysis: is tested into number
According to solar chimney electricity generation system similar to the Central China University of Science and Technology, (thermal-arrest canopy diameter is 10m, chimney height 8m, and thermal-arrest canopy inclines
Angle is 8 °) turbine output power comparison.Its experimental data is carried out to take comparison an analysis such as Figure 30.It can be seen that this experiment
Turbine system performance is relatively high.The reason is as follows that: first, experiment location is different, solar irradiation intensity and testing time
It is different.Second, in comparative experiments, ambient wind velocity is not tested, does not account for ambient wind velocity to turbine system
Coupled Interaction Analysis causes this experimental data different from its data difference.Third, this experiment pass through to Hohhot district local
Practical area feature sunlight irradiation profile optimizes solar chimney electricity generation system thermal-arrest canopy inclination angle, and to turbine blade
It is tested after optimizing analysis, illustrates that effect of optimization is significant.
3. solar chimney electricity generation system efficiencyThe analysis of 3.1 thermal-arrest canopy collecting efficiencies
Thermal-arrest canopy is equivalent to a sunlight collection device, and recuperation layer collects solar irradiation, and after temperature increases, heating flows through storage
The air on thermosphere surface increases air themperature in thermal-arrest canopy canopy, and there are certain temperature difference with external environment.Pass through BSRN3000
Radiation observation system acquires solar irradiation, carries out examination collecting system experiment measured data analysis.It chooses each hourly average value and calculates collection
Hot canopy internal-external temperature difference, by calculating it can be concluded that collecting system collecting efficiency, such as Figure 31 in testDate.To test July on date 6
It is analyzed for day, as shown in Figure 31, experiment test is during 9:30-13:00, as solar irradiation increases, thermal-arrest canopy collection
The thermal efficiency is distributed in sine curve, and in morning 11:30, collecting efficiency peak value reaches 1.35%.Due to by Inner Mongolia environment
The influence of wind speed unstable factor, ambient wind velocity increases during afternoon 13:00-15:00, and a small amount of wind blows into canopy from thermal-arrest canopy import
Interior, recuperation layer heat largely scatters and disappears, and temperature of shed decline, canopy internal-external temperature difference reduces, and thermal-arrest canopy efficiency reduces.
3.2 chimney efficiency analysis: chimney provides dynamic in solar chimney electricity generation system for upward motion of air in thermal-arrest canopy
Power.The outlet of thermal-arrest canopy is closely coupled with solar chimney input end, and chimney import hot fluid temperature and chimney breast end ring border are empty
There are the temperature difference for temperature degree, cause chimney entrance atmospheric density lower than thermal-arrest canopy external environment atmospheric density, are formed inside and outside thermal-arrest canopy
Thus atmospheric density difference generates pressure difference, generate the suction force of air uplink in solar chimney, air is due to by suction force
Effect, speed increases, and in thermal-arrest canopy exit chimney inlet, speed is maximum, and the air with certain kinetic energy pushes whirlpool herein
Engine blade wheel acting power generation.As shown in Figure 32, solar chimney efficiency whole day is totally in rising trend, to afternoon since test
It is in rising trend before 14:00.Due to air in solar irradiation increase heating canopy, hot fluid is flowed out from solar chimney, so that
Solar chimney is imported and exported there are the temperature difference, and difference increases with the variation of time, and solar chimney efficiency reaches peak value
11.423%.Meet temperature rise increase, suction force increases, and efficiency increases.After 14:00, due to being influenced by ambient wind velocity, pass in and out
Air mass flow increases in thermal-arrest canopy, causes solar chimney exit there are negative pressure, and solar chimney import and export increases by one
Suction force caused by increasing due to extraneous wind speed.And the buoyancy lift generated with thermal-arrest canopy canopy internal-external temperature difference is coupled to be superimposed and causes
16:00-15:00 reaches chimney efficiency peak 18.45% again.
3.3 turbine generation efficiency analysis: turbine generation efficiency is turbine output coefficient and generator electromechanical efficiency
Product, turbine output coefficient be turbine in solar chimney electricity generation system turbine chimney entrance wind energy benefit
Use ratio.If Figure 33 is turbine generation efficiency distribution curve, as the solar irradiation time increases, thermal current speed before turbine
It is gradually increased, turbine wind energy utilization is gradually increased, in the afternoon 14:30 or so, and solar chimney entrance wind speed is
1.011m/s, turbine generation engine efficiency reach peak value 5.47%, and the wind energy efficiency of solar chimney entrance is maximum at this time.
3.4 solar chimney electricity generation system efficiency analysis: the collecting system of solar chimney electricity generation system combination thermal-arrest canopy,
Chimney systems and turbine wind mill electricity generation system tripartite system efficiency, obtain the gross efficiency of solar chimney electricity generation system.Such as
Figure 34 is solar chimney electricity generation system efficiency distribution curve, and during test, solar chimney electricity generation system efficiency is integrally presented
The trend of liter, afternoon, 16:30 or so reached peak value, and extraneous solar radiation reduces at this time, but recuperation layer temperature is higher, inside and outside thermal-arrest canopy
There are the temperature difference, the collecting efficiency of thermal-arrest canopy is 1.09%.Solar chimney efficiency is higher simultaneously, is influenced by ambient wind velocity, increases
Suction force in smokestack, solar chimney efficiency is 18.45%, so that the efficiency of whole system is relatively high, solar energy cigarette
Chimney electricity generation system efficiency reaches 0.01%.By above data analysis as can be seen that due to being in solar chimney electricity generation system
System reasons in structure, causes collecting efficiency, chimney efficiency and turbine efficiency larger by such environmental effects.Wherein due to exhale with it is great
Specially area's meteorological condition influence causes collecting efficiency relatively low.But it can also be seen that wind speed increases, relatively since meteorological condition influences
The coupling suction force for increasing chimney improves chimney efficiency.Therefore, appropriate reconstruction is carried out to solar chimney power generation system structure,
Solar chimney electricity generation system collecting efficiency can be improved.
4. conclusion: the utility model, which passes through, determines solar energy chimney generator turbine blade basic parameter, uses
Profili software calculates turbine blade aerofoil profile Choosing Type Analysis, the best aerofoil profile of selection matching solar chimney electricity generation system.
And selection aerofoil profile progress further optimizes aerofoil profile and calculation of aerodynamic characteristics by CST aerofoil optimization method.It improves
The optimal wind energy utilization rate of turbine blade, tests by performance test, reaches design requirement.Pass through Airfoil Design and the CST wing
Type optimization method, design optimization are suitable for the turbine blade of solar chimney electricity generation system, to improve turbine blade wind energy
Utilization rate, which optimizes, is calculated as turbine blade layout offer new approaches.Solar energy cigarette is carried out using low speed revolution wind-tunnel
Chimney turbine blade performance carries out test experiments, obtains solar chimney turbine hair by turbogenerator external characteristics test experiments
Motor Foundation data.It is analyzed, is drawn most for solar chimney turbine system turbine blade tip-speed ratio, power parameter
Big characteristics of output power curve, power coefficient characteristic curve.Solar chimney electricity generation system turbine output power is surveyed
Try analysis of experiments.Test error is analyzed, provides test basis to improve solar chimney electricity generation system efficiency.To solar chimney
Electricity generation system carries out output power test experiments, the collecting efficiency of solar chimney electricity generation system, chimney efficiency, turbine efficiency
Test analysis evaluation is carried out with system total efficiency.Domestic similar solar chimney electricity generation system output power analysis by contrast, property
It can be better than homogeneous system.Show the optimization based on the thermal-arrest canopy inclination angle under the conditions of Hohhot district local latitude and solar irradiation
Design and experiment test, and the optimization of solar chimney turbine blade is analyzed, to promotion solar chimney electricity generation system
Gross efficiency method is correct, and effect is obvious.
Claims (3)
1. turbine blade, which is characterized in that blade is NACA2408 aerofoil profile, and angle of attack value is 6-8 °, and maximum curved surface 2.0% exists
40.6% wing chord, diameter D are 0.12m；Wing chord of the maximum gauge 8.01% 30.1%；Each sectional parameter of vane airfoil profile is as follows
Shown in table:
R is chord length at section, and R is wing chord total length.
2. solar chimney electricity generation system, which is characterized in that including the use of turbine blade described in claim 1 (1), connection
Bracket (2), turbogenerator (3) and chimney entrance pedestal (4), the chimney entrance pedestal (4) is by lower cylindrical drum (41), centre
Frustum cone cylinder (42) and upper cylindrical drum (43) composition, the top and bottom end of the intermediate frustum cone cylinder (42) respectively with the upper cylindrical drum
(43) be fixedly connected with the lower cylindrical drum (41), and the internal diameter on the intermediate frustum cone cylinder (42) top and outer diameter with it is described
The internal diameter and outer diameter of upper cylindrical drum (43) are equal, the internal diameter and outer diameter of intermediate frustum cone cylinder (42) bottom end with the lower cylinder
The internal diameter and outer diameter of cylinder (41) are equal；The connecting bracket (2) is by motor installation cylindrical drum (21), connecting rod (22) and clinch
(23) it forms, one end of the connecting rod (22) is fixedly connected with motor installation cylindrical drum (21), the other end is taken with described
Socket part (23) is fixedly connected with and offers in the connecting rod (22) axis and the axis of motor installation cylindrical drum (21) is flat
Capable ventilation hole (23), the turbogenerator (3) are mounted in motor installation cylindrical drum (21), the clinch (23)
On be provided with arc overlap joint slot (231), the connecting bracket (2) by the arc overlap joint slot (231) be mounted on the upper circle
On column casing (43), the axis of the turbine blade (1) and the power intake of the turbogenerator (3) are drivingly connected.
3. solar chimney electricity generation system according to claim 2, which is characterized in that lower cylindrical drum (41) φ
135mm, high 85mm；The high 54mm of the intermediate frustum cone cylinder (42)；Upper cylindrical drum (43) φ 113mm, high 50mm.
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| CN109340042A (en) * | 2018-11-19 | 2019-02-15 | 内蒙古工业大学 | Turbine blade and its design method and solar chimney electricity generation system |
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2018
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109340042A (en) * | 2018-11-19 | 2019-02-15 | 内蒙古工业大学 | Turbine blade and its design method and solar chimney electricity generation system |
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