Title of Invention

VERTICAL AXIS WINDMILL WITH STREAM LINED BLADES

Abstract

The present invention solves this problem to large extend with help of a new machanism called stream lined blading (SLB). acorrding to this technique the force blades are extracting power from the wind, when it is positioned in power production sector of the rotor. when these blades are comes to the other half of the rotor, the blades turn and arrange itself in-line with the wind flow. hence, the other half the rotor is not sufferning by unwanted drag, which stalls the rotor. thus the power output of the mill improves considerably compared to existing verity axix wind mill. the working principle of this mill is similar to conventional vertilcal axis wind mill. the rotor of the mill is divided into two half portion namely force d=side and drag side. the blades which are obstructing the wind are called force blades and are responsible for turning of rotor. the blades which are not obstructing the flow or aligning itself with the wind flow are called stream lined blading.

Full Text

The present invention relates to vertical axis windmill, and more particularly using rotor with stream lined blading technology to get maximum power output. Background of present invention: A plenty of energy is needed to sustain industrial growth and agricultural production. The existing sources of energy such as coal, oil, uranium and other conventional energy may not be adequate to meet the ever increasing energy demands. These conventional sources of energy are also depleting and may be exhausted at the end of the century or beginning of the next century. To overcome these problems by using several non-conventional energy sources. These energy sources are free from pollution, available in large quantities and well suited for decentralized use. Wind energy is one among them and it has better advantages than the other non conventional energy sources. Our society continues to look for alternate methods of electricity generation that are economical and environmental friendly. The environmental costs of the continued use of power generation facilities that use nonrenewable resources continue to become apparent to our society. Therefore, technological advances using renewable energy sources are going to be extremely important in the future. Wind power is one renewable energy source that is particularly important to rural locations. This energy does not pollute the atmosphere, fuel provision and transports are not required. Generation of electricity continues to improve and will increase in importance to the overall energy future of our society. Correspondingly, electrical energy consumption will increase as our population and economy continues to grow. Wind turbines are machines that convert the kinetic energy of the wind into mechanical energy. When the mechanical energy is converted to electricity, then the machine is referred to as a wind turbine, or a wind energy converter. When such mechanical energy is used directly by machines such as pumps, then the machine is referred to as a 'windmill'. Today's wind machines use blades to collect the wind's kinetic energy. Windmills work because they slow down the speed of the wind. The wind flows over the airfoil shaped blades causing lift, like the effect on airplane wings, causing them to turn. The blades are connected to a drive shaft that turns an electric generator to produce electricity. Types of Wind Turbines: • Horizontal-axis wind turbines (HAWT) • Vertical-axis wind turbines (VAWT) Horizontal Axis Wind Turbine (HAWT): Horizontal-axis wind turbines (HAWT) have the main rotor shaft and electrical generator at the top of a tower, and must be pointed into the wind. Small turbines are pointed by a simple wind vane, while large turbines generally use a wind sensor coupled with a servo motor. Most have a gearbox, which turns the slow rotation of the blades into a quicker rotation that is more suitable to drive a generator. Wind turbines capture the wind's energy with two or three propeller-like blades, which are mounted on a rotor, to generate electricity. The turbines sit high atop towers, taking advantage of the stronger and less turbulent wind at 100 feet (30 nneters) or more aboveground. A blade acts much like an airplane wing. When wind blows, a pocket of low-pressure air forms on the downwind side of the blade. The low-pressure air pocket then pulls the blade toward it, causing the rotor to turn. This is called lift. The force of the lift is actually much stronger than the wind's force against the front side of the blade, which is called drag. The combination of lift and drag causes the rotor to spin like a propeller, and the turning shaft spins a generator to make electricity. Vertical-Axis Wind Turbines (or VAWTs): Vertical-axis wind turbines have the main rotor shaft running vertically. Key advantages of this arrangement are that the generator and/or gearbox can be placed at the bottom, near the ground, so the tower doesn't need to support it, and that the turbine doesn't need to be pointed into the wind. Drawbacks are usually pulsating torque that can be produced during each revolution and drag created when the blade rotates into the wind. It is also difficult to mount vertical-axis turbines on towers, meaning they must operate in the often slower, more turbulent air flow near the ground, resulting in lower energy extraction efficiency. Advantages of Vertical Axis Wind Turbines: • Does not need to be pointed into the wind, can turn regardless of the direction of the wind. • Being rotation, requires less space for its rotation and consequently can be used a large number of them within a smaller area and consequently generate greater energy and more effective utilization of the wind. • Being vertical the area of the blades which the wind moves are much more than the traditional mills because the blades are subjected to the same angle from all heights and consequently better utilization and much more effectiveness from the blades of the traditional mills. • Easier to maintain, because most of their moving parts are located near the ground. This is due to the vertical wind turbine's shape. The airfoils or rotor blades are connected by arms to a shaft that sits on a bearing and drives a generator below, usually by first connecting to a gearbox. • As the rotor blades are vertical, a yaw device is not needed, reducing the need for this bearing and its cost. • Vertical wind turbines have a higher airfoil pitch angle, giving improved aerodynamics while decreasing drag at low and high pressures. • Low height useful where laws do not permit structures to be placed high. • Does not need a free standing tower so is much less expensive and stronger in high winds that are close to the ground. • Usually have a lower Tip-Speed ratio, so less likely to break in high winds. • Less dangerous to birds. • Lower maintenance costs because their critical equipment is more accessible. • Lower capital costs due to simpler design. • More acceptable because of lower profile - less visual pollution. • Superior handling of high gusts of winds. Disadvantages of Vertical Axis Wind Turbines: • Most vertical axis wind turbines produce energy at only 60% of the efficiency of horizontal axis wind turbines in large part because of the additional drag that they have as their blades rotate into the wind. • There may be a height limitation to how tall a vertical wind turbine can be built and how much sweep area it can have. However, this can be overcome by connecting a multiple number of turbines together in a triangular pattern with bracing across the top of the structure. Thus reducing the need for such strong vertical support, and allowing the turbine blades to be made much longer. • Most vertical axis wind turbines need to be installed on a relatively flat piece of land and some sites could be too steep for them but are still usable by horizontal axis wind turbines. Most vertical axis wind turbines have low starting torque, and may require energy to start the turning. The invention UA74031 illustrates wind power engineering, namely to rotary windmills, which may be used in wind electrical generators or equipments for conversion of wind energy into electrical energy. An object of the present invention is to increase efficiency, power of wind motor and to improve starting acceleration of the rotor. Windmill comprises a rotor with power elements that are realized in the form of two symmetrically arranged blocks and of aerodynamic cascades wherein each block advantageously consists of four blades realized in the form of a turbine-type configuration of blades. Blocks and of aerodynamic cascade are mounted on central vertical shaft. Cascaded blade profiles are in the form of subsonic aerodynamic profiles The invention W02006102719 resides in a windmill having a support structure arranged to be rotatable about a vertical axis, and at least one set of louvres, each being configured with a leading edge and a trailing edge, opposed faces bounded by said edges and between opposite ends thereof, and at least one of said ends being pivotally supported by said support structure. The at least one set of louvres is arranged so that in one revolution of said support structure each louvre traverses a power zone, a first change over zone, a return zone, and a second change over zone which is substantially opposite to said first change over zone. In said power zone, the louvres of the at least one set of louvres are arranged with one of their opposed faces presented towards prevailing wind and adjacent louvres overlapping one another, and in said return zone, the louvres of the at least one set of louvres are arranged with their leading edges pointing substantially towards the prevailing wind with a gap between the adjacent louvres. In said first and second change over zones, the louvres pivotal move to respectively present said one face and said leading edge thereof towards the prevailing wind. The invention US 06/166,125 illustrates that windmill of the vertical axis type having a plurality of circumferentially and radially outwardly spaced rotatably mounted vanes vertically parallel to the axis shaft wherein means are provided for controlling multistage feathering of the vanes in conjunction with said vanes feathering to rotate on their individual axes in a direction opposite to the direction of rotation of the windmill assembly in increments of 45 degrees twice for each blade before finally feathering a final half rotation completing the rotation of 360 degrees on its individual axis while the windmill makes one revolution, thus repeatedly repositioning the blades to the most optimum resistance angle to the wind as the windmill rotates increasing the power angle to near seventy-five percent of the circle of the windmill rotation, a construction option prevailing to routinely cause all the blades to feather when near a zero angular position to the wind, and having associated therewith a conglomerate of mechanical phenomena to perform said functions and to release all blades in the event of a wind velocity exceeding a safe speed for the structure, bringing the windmill to a stop until the wind velocity recedes to a safe precalculated speed causing the windmill to automatically resume operation, characteristic of the total and complete automatism of this windmill. Summery of the invention:- An object of this invention is to overcome the above mentioned drawbacks, and to provide a design that is cheaper, practical and commercially viable. A vertical axis windmill with stream lined blades is characterized that it comprising: a vertical axis rotor(1) consists of two center plates one in the top and another in the bottom; a aerofoil blade(2) means is mounted over the swivel base between top and bottom radial arms where the rotation of the blade is stopped by a stopper ; a rotor support bearing(3) where the power is transmitted to the final drive; a speed regulation device (4) consisting of cylinder, piston, connecting rod and crank shaft; a power generator(5) which is designed for producing rated power output. The method of operation of vertical axis windmill with stream lined blades characterized therein wherever force blades come to the other half of the rotor, the blades are pulled away from the stopper by the wind flow and aligned itself to the direction of wind flow hence this method is offering lower drag and posses more power extracting capability from the wind. Detailed description of the invention: This mill consists of a vertical axis rotor, stream lined blades, rotor support bearing, speed regulation device, gear box, power generator and supporting frame. Vertical Axis Rotor This rotor consists of two center plates, one in top and another in bottom and twelve blades. Each blade having two radial arms. The inner end of radial arms is fastened to the center plate using bolt and nuts. The other end of the radial arms is holding the fixture of stream lined blades. A centre shaft connects top and base plates and held firmly to transfer wind energy to shaft without any slip. The lower end of the rotor shaft fixed with the support bearing and final drive. Aerofoil blades An aerofoil shaped steel blades mounted over the swivel base, between the top and bottom radial arms. The rotation of blade is stopped by a stopper provided in the radial arms. It prevents the full rotation of aerofoil blades. Rotor Support Bearing It supports the rotor shaft and transmits power of the rotor to the final drive. Speed Regulation Device It is a specially designed mechanical type, speed regulation device that consisting of cylinder, piston, connecting rod, and crank shaft. This device is used to maintain the constant speed of the rotor irrespective of wind velocity. In this set up, a small hole is drilled in the cylinder head to restrict inflow and outflow of air during operation. This device is connected to the main shaft of the rotor next to rotor support bearing. Gear Box Normally, windmill rotors are permitted to rotate under specified lower rpm. This lower rpm must be increased to the desired rpm, required by power generator using gear trains. Power Generator It is an ordinary AC generator designed for producing rated power output. Generally the generator coupled with windmills is capable of withstanding higher load. Hence, the power generator coupled with windmills should have 25% of higher power than the designed power. Supporting Frame Structured steel, supporting frame having wider base and shorter height provided under the mill to withstand maximum bending moment, torsional vibration and reactive torque supplied by the rotor during operation. PRINCIPLE OF WORKING The working principle of this mill is similar to conventional vertical axis wind mill. The rotor of the mill is divided into two half portion namely force side and drag side. The blades which are obstructing the wind flow are called force blades and are responsible for turning of rotor. The blades which are not obstructing the flow or aligning itself with the wind flow are called stream lined blading. When force blades come to the other half of the rotor, the blades are pulled away from the stopper by the wind flow and aligned itself to the direction of wind flow. Hence, this special mechanism is called stream lined blading. The primary advantage of this method is offering lower drag. Compared to conventional type of vertical axis wind mill, it posses more power extracting capability from the wind. The speed regulator specially made for this purpose consisting of cylinder, piston, connecting rod and crank shaft. It is fixed to the main shaft of the rotor next to support bearing. It works based on nozzle principle (condition for maximum discharge). That is, a hole of desired size is drilled over the cylinder head and allows one particular rate of flow. Suppose the flow rate exceeds the maximum limit, the inside pressure (positive or negative pressure) stalls the movement of the piston. Hence, the system always allows constant piston velocity and thus the speed of the rotor remains constant irrespective load. DESIGN FORMULAS Design of vertical axis wind mill consists of rotor part and speed regulation mechanism. These two designs are derived from empirical relations. Formulas for Rotor design 1) Force acting on each blade due to wind velocity(F) =p*A*C^*sine Where, p-density of air (kg/m^), A-projected area (m^), ie. (blade length*projected width) C-wind velocity (m/s), 0-angle of blade with respect to wind direction. 2) Torque created by each blade = F*R Where, F-force acting on each blade (N), R-radial distance (m). 3) Total torque (T) = torque in first blade + torque in second blade + torque in third blade + 4) Optimum value for maximum power (a) = U/C Where, U-tangential speed (m/s), C-wind speed (m/s), Optimum value of blade to wind velocity ratio is 1/3. 5) Tangential speed = r*co Where, r-radius of rotor (m), Q)-angular velocity (m/s). 6) Angular velocity(cD) = (2*7t*N/60) in rad/sec N-speed of rotor (rpm). 7) Power (P) = (2*7u*N*T/60) in watts. Formulas for Speed Regulation 1) Ratio of length of connecting rod to crank radius (n) = L/Rc Where, Rc-crank radius (m), L-length of connecting rod (m). 2) Maximum velocity of piston (Vp) = co*Rc*{sina+sin2a/2n} Where, a-crank angle from the inner dead centre at which the maximum velocity occurs, 3) Critical pressure ratio (P2/P1) = (2/n+1) ^ (n/n-1) Where, P2-throat pressure, PI-inlet pressure, n-for saturation condition, ie. (n=1.135), There fore (P2/P1) =0.58. 4) Piston force (f) = (rotor torque/crank radius). 5) Inlet pressure (PI) = (Piston force/area of piston). 6) Bemolli's equation {(Pl/pg)+(VlV2g)+zl}={(P2/pg)+(V2V2g)+z2} Where, VI-inlet velocity (m/s), V2-throat velocity (m/s), PI-inlet pressure (N/m^), P2-throat pressure (N/m^). 7) Continuity equation Q1=Q2 ie. A1V1=A2V2. Where, Q1-cylinder discharge (mVs), Q2-throat discharge (m^/s). CALCULATION FOR ROTOR DESIGN Essential assumed data: Wind velocity (C) = 8m/s, Rotor diameter (d) = 6m, Blade width (W) = Im, Blade height (L) = 2m, Number of blades = 12. The rotor design should representation. The above values should be taken as appropriate scale down. From figure 5.2 gives the radius of blade according to the wind velocity and blade projected width. These values are. First blade Radial distance (Rl) Projected width (Bl) Second blade Radial distance (R2) Projected width (B2) Third blade 2.7974m, 0.4019m, 2.5m, 0.866m, 2.6878m, 0.5m, Radial distance (R3) Projected width (B3) Force on each blade. p*A*C2*sine, p*(L*Bl)*C2*sine, 1.23*(2*0.4019)*82*sin90°, 63N. 1.23*(2*0.866)* 82*sin60°, 113N. F1 = F1 F2 F2 F3 F3 1.23*(2*0.5)* 82*sin30°, 41.32N. Torque on each blade. F1*R1, 63*2.7974, 177Nm. 113*2.5, 288.15Nm. 41.32*2.6878, T1 = T1 = T2 = T2 = T3 = T3 = 103.3Nm. Total torque (T) = T1+T2+T3, u/c, U/8, 2.67m/s. 177+288.15+103.3, T = 570Nm. Optimum value for maximum power (a) 1/3 = U Tangential speed (U) = 2.67 = 0) = Angular velocity (co) = 0.89 = Speed of rotor (N) = Power output (P) = r*a), 3*®, 0.89rad/sec. (2*7r*N/60) in rad/sec, (2*7t*N/60), 8.5rpm. (2*7t*N*T/60), (2*71*8.5*570/60), 510watts. CALCULATION FOR SPEED REGULATION Essential assumed parameters Piston diameter (D) = 25cm, Crank radius (Rc) = 17.5cm, Length of connecting rod (L) = 56cm, Stroke length = 35cm. Connecting rod to crank ratio (n), n = L/Rc, n= 56/17.5, n= 3.2. Velocity of piston Vp = VI = a)*Rc* {sina+sin2a/2n}, For maximum velocity of piston, dVp/da - 0, co*Rc* {cosa+2cos2a/2n} (2ncosa + 2cos2a)/2n 2cos2a + 3.2cosa- 1 Solve above equation, Therefore, Piston force (f) Inlet pressure (PI) 0.58, 0.58, 38485.26 N/m^. Cosa = 0.3427 a - 70°. Velocity of piston (VI) = co*Rc* {sina+sin2a/2n}, 0.89* 17.5* {sin70°+sinl4072*3.2}, VI = 1.0401 m/s. = torque (T) / radius of rotation (Rc), 570/0.175, f = 3257.14 N. piston force / area of piston (Al), 3257.14/(71*0.1252), 66353.91 N/m^. Critical pressure ratio, P2/P1 P2/66353.91 Therefore, Throat pressure (P2) = Bemolli's equation, {(Pl/pg) + (VP/2g) + zl} = {(P2/pg) + (V2V2g) + z2}, {(66353.91/1.23*9.81) + (1.040V2*9.81)} = {(38485.26/1.23*9.81) + (V2V2*9.81)}, = 0, = 0, = 0, and cosa = -1.8677 (negligible) Therefore, Throat velocity V2 = 212.87 m/s. Discharge Q1 = Q2, AlVl = A2V2, (0.252*1.040) = (d2*212.87), Therefore, Throat diameter (d) = 0.01747m. Detailed description of drawings- The invention will now be apparent from the following non- limitative description witli reference to the accompanying drawings, in which- Fig.1 shows a constructional feature of vertical axis wind mill according to an embodiment of the present invention; Fig.2 shows cut sectional view of aerofoil blade of the invention. Fig. 3 shows speed regulation device of the invention. Fig. 4 shows gear box of the invention. Fig. 5 shows steam lined blading of the invention. With reference to fig.1, This rotor(1) consists of two center plates, one in top and another in bottom and twelve blades. Each blade having two radial arms. The inner end of radial arms is fastened to the center plate using bolt and nuts. The other end of the radial arms is holding the fixture of stream lined blades(2). A centre shaft connects top and base plates and held firmly to transfer wind energy to shaft without any slip. The lower end of the rotor shaft fixed with the support bearing(3) and final drive. With reference to fig. 2, an aerofoil shaped steel blacles(7) mounted over the swivel base, between the top and bottom radial arms. The rotation of blade is stopped by a stopper provided in the radial arms. It prevents the full rotation of aerofoil blades. With reference to fig. 3 It is a specially designed mechanical type, speed regulation device that consisting of cylinder(11), piston(10), connecting rod(9), and crank shaft(8). This device is used to maintain the constant speed of the rotor irrespective of wind velocity. With reference to fig. 4 windmill rotors are permitted to rotate under specified lower rpm. This lower rpm must be increased to the desired rpm, required by power generator using gear trains. With reference to fig. 5 steam lined blading, the working principle of this mill is similar to conventional vertical axis wind mill. The rotor of the mill is divided into two half portion namely force side and drag side. The blades which are obstructing the wind flow are called force blades(13) and are responsible for turning of rotor. The blades which are not obstructing the flow or aligning itself with the wind flow are called stream lined blading(14). I Claim: 1. A vertical axis windmill with stream lined blades is characterized that it comprising: a vertical axis rotor(1) consists of two center plates one in the top and another in the bottom; a aerofoil blade(2) means is mounted over the swivel base between top and bottom radial arms where the rotation of the blade is stopped by a stopper ; a rotor support bearing(3) where the power is transmitted to the final drive; a speed regulation device (4) consisting of cylinder, piston, connecting rod and crank shaft; a power generator(5) which is designed for producing rated power output. 2. A vertical axis windmill with stream lined blades as claimed in claim 1 wherein vertical axis rotor (1) means which has twelve blades. 3. A vertical axis windmill with stream lined blades as claimed in claim 2 wherein each blade is having two radial arms. 4. A vertical axis windmill with stream lined blades as claimed in claim 3 wherein the inner radial arm is fastened to the center plate by bolt and nuts. 5. A vertical axis windmill with stream lined blades as claimed in claim 1 wherein the full rotation of aerofoil blades is prevented by a stopper provided in the radial arm. 6. A vertical axis windmill with stream lined blades as claimed in claim 1 wherein the speed regulation device maintains constant speed irrespective of wind velocity. 7. A vertical axis windmill with stream lined blades as claimed in claim 6 wherein the speed regulation device has a hole of desired size is drilled over the cylinder head and allows one particular rate of flow. 8. The method of operation of vertical axis windmill with stream lined blades characterized therein wherever force blades come to the other half of the rotor, the blades are pulled away from the stopper by the wind flow and aligned itself to the direction of wind flow hence this method is offering lower drag and posses more power extracting capability from the wind. 9. A vertical axis windmill with stream lined blades substantially as herein described with reference to accompanying drawings.

Documents:

1227-CHE-2008 AMENDED PAGES OF SPECIFICATION 05-09-2013.pdf

1227-CHE-2008 AMENDED CLAIMS 05-09-2013.pdf

1227-CHE-2008 AMENDED CLAIMS 19-07-2013.pdf

1227-CHE-2008 CORRESPONDENCE OTHERS 19-07-2013.pdf

1227-CHE-2008 ABSTRACT.pdf

1227-CHE-2008 CLAIMS.pdf

1227-CHE-2008 CORRESPONDENCE PO.pdf

1227-CHE-2008 DESCRIPTION (COMPLETE).pdf

1227-CHE-2008 DRAWINGS.pdf

1227-CHE-2008 FORM-1.pdf

1227-CHE-2008 FORM-18.pdf

1227-CHE-2008 FORM-9.pdf

1227-CHE-2008 OTHERS 19-07-2013.pdf