Next Generation Wind/Water Turbines
Reducing the reliance on fossil fuel for the generation of power is a global priority. Several alternative energy sources have been identified and first generation equipment is already being utilised to harness wind, water, solar and geothermal energy, but in many cases the scope of these installations is limited by design issues.
By Anatoly Arov, Inventor, Canada
Flow Engine
The Flow Engine design concept for turbines addresses the key problem common to all reaction turbines – the differential properties of vanes factor. As a starting point for the flow engine design the vertical axis hinged turbine was first considered. This design virtually eliminates the differential factor but only allows half of the flow swept area to be used for energy generation. The novel design features of the Flow Engine eliminate the resistance effect while doubling the swept area by introduction of two counter-rotating rotors with hinged vanes occupying the same flow swept area resulting in four times the energy output. This has been accomplished, without complicated gears or other mechanisms, by removing the fixed mounting of the vanes and allowing the vanes to oscillate freely in an arc of 90 degrees from the horizontal to the vertical (see Figure 3), and the introduction of opposite counter-rotating rotors with vanes sharing the same swept area (see figures), their oscillation being powered by flow. The impeller assemblies rotate in opposite directions doubling the absolute speed delivered to the planetary or bevel gearbox and allowing the generator to operate at higher rpm and higher efficiency. In addition, it is possible to stack the impellers in several ways which, in some cases, doubles the efficiency of the flow engine. Combining these improvements has improved the electrical power output of the prototype by up to 4 to 4.5 times.
Summary of Features
Objective
Test Flow Engine as wind turbine, and also for water applications, to establish performance criteria.
Test sites
Water – National Research Council of Canada – Canadian Hydraulics Center, Ottawa
Wind – our laboratory
Prototype dimensions and test conditions
Rotor 0.5m diameter, 0.34m height, (two levels of vanes), separating discs attached, PMA alternator DC540 rated @130 rpm and 10.6V DC in no-load condition and providing maximum 4.2 watt @ 5.3V DC under optimal load at the same speed; gearbox 6:1, water swept area 0.17 square metres, active water (vane) surface 0.07 square metres, vane centre is located Rav = 0.15m from rotor shaft, rotors vanes shifted 45% and both rotors rotating in the same direction.
Theoretical calculations
Expected power
Results
Conclusions
Anatoly Arov is a mechanical engineer with a PhD from a Moscow scientific organisation. He made several inventions in Russia, then emigrated to Canada in 1981 and established the company PIPS (Productivity Improvement and Problem Solving) in 1983. He is now a Canadian citizen, and his inventions in Canada have included a combustion engine, a computer storage device, a DC to AC conversion method and device, Flow Engines, a future car concept and a deep water pressure utilisation method for water energy utilisation). Most of his inventions have been developed to the prototype stage.{/access}
Reducing the reliance on fossil fuel for the generation of power is a global priority. Several alternative energy sources have been identified and first generation equipment is already being utilised to harness wind, water, solar and geothermal energy, but in many cases the scope of these installations is limited by design issues.By Anatoly Arov, Inventor, Canada
{access view=!registered}Only logged in users can view the full text of the article.{/access}{access view=registered}Wind and water energy can be harnessed in two major ways: either with lift turbines or reaction turbines. Lift turbine design has reached a point where only small improvements can be made, usually focusing on increasing the efficiency of the impeller blades. Several efforts have been made to introduce different designs.
Reaction turbines have been a less favoured option for commercial wind and water turbine design. They are sometimes perceived as inefficient because of the differential property of their blades or vanes (i.e. they capture wind or water force efficiently in one direction but when moving in the other direction the vanes exhibit residual resistance). Because of this constant resistance effect they are often seen as inefficient and are sometimes referred to as drag machines. However, this kind of design has many potential advantages: they are simpler to assemble and manufacture, the generator can be placed at the platform level for ease of maintenance and they do not require rotation to accommodate wind direction and can be used in shallow waters. Because of their potential advantages a number of efforts have been made to increase efficiency by altering the rotation position of the vanes to minimise wind resistance. Although these have successfully increased the power generated they dramatically increase the complexity of design.Flow Engine
The Flow Engine design concept for turbines addresses the key problem common to all reaction turbines – the differential properties of vanes factor. As a starting point for the flow engine design the vertical axis hinged turbine was first considered. This design virtually eliminates the differential factor but only allows half of the flow swept area to be used for energy generation. The novel design features of the Flow Engine eliminate the resistance effect while doubling the swept area by introduction of two counter-rotating rotors with hinged vanes occupying the same flow swept area resulting in four times the energy output. This has been accomplished, without complicated gears or other mechanisms, by removing the fixed mounting of the vanes and allowing the vanes to oscillate freely in an arc of 90 degrees from the horizontal to the vertical (see Figure 3), and the introduction of opposite counter-rotating rotors with vanes sharing the same swept area (see figures), their oscillation being powered by flow. The impeller assemblies rotate in opposite directions doubling the absolute speed delivered to the planetary or bevel gearbox and allowing the generator to operate at higher rpm and higher efficiency. In addition, it is possible to stack the impellers in several ways which, in some cases, doubles the efficiency of the flow engine. Combining these improvements has improved the electrical power output of the prototype by up to 4 to 4.5 times.
Summary of Features
- Vertical (both wind and water) or horizontal (water only) axis of rotation.
- Driving higher absolute speed directly to the generator or to the gearbox with two impellers rotating in opposite directions.
- Possibility of stacking several impellers and Selective Leverage Technique (SLT) incorporation (see energy efficiency Patent Canada 2,504,057).
- Simple to manufacture/install/service, and scalable.
- Does not require rotation to accommodate the direction of wind/water/tides/waves.
- Can harness the wind energy on rooftops and water energy at shallow depths and can accommodate lower height requirements for offshore installations.
Objective
Test Flow Engine as wind turbine, and also for water applications, to establish performance criteria.
Test sites
Water – National Research Council of Canada – Canadian Hydraulics Center, Ottawa
Wind – our laboratory
Prototype dimensions and test conditions
Rotor 0.5m diameter, 0.34m height, (two levels of vanes), separating discs attached, PMA alternator DC540 rated @130 rpm and 10.6V DC in no-load condition and providing maximum 4.2 watt @ 5.3V DC under optimal load at the same speed; gearbox 6:1, water swept area 0.17 square metres, active water (vane) surface 0.07 square metres, vane centre is located Rav = 0.15m from rotor shaft, rotors vanes shifted 45% and both rotors rotating in the same direction.
Theoretical calculations
Expected power
| Flow speed | Water V = 1.5 m/s Wind V = 14 m/s | |
| expected Fmax force on vanes in stalled condition; rotational speeds; and Cp = 0.135 = (0.67 + 0.11) * (0.67 + 0.11) * (0.33 – 0.11) |
Water Fmax = | (1000/2) * 1.5 * 1.5 * 0.07 = 79 n |
| Wind Fmax = | (1.2/2) * 14 * 14 * 0.07 = 8 n | |
| Water N = | (2/3) * 1.5/(3.14 * 0.5) = 0.64 = 38 rpm (rotor rotational speed in no-load); N1 = (2/3) * N = 25 rpm (rotor speed under load) | |
| Wind N = | (2/3) * 14 /(3.14 * 0.5) = 10.18 = 356 rpm (no-load); N1 = (2/3) * N = 237 rpm (rotor speed under load) | |
| Water Watt = | 0.135 * (1000/2) * 1.5 * 1.5 * 1.5 * 0.07 = 16 | |
| Wind Watt = | 0.135 * (1.2/2) * 14 * 14 * 14 * 0.07 = 16 | |
| Conventional turbine with the same flow swept area | Water Watt = | 0.2 * (1000/2) * 1.5 * 1.5 * 1.5 * 0.17 = 58 |
| Wind Watt = | 0.2 * (1.2/2) * 14 * 14 * 14 * 0.17 = 58 | |
Results
| Test results (best of several tests) | Water 1.5 m/s |
| No-load, no gearbox, no generator, rotor No = 38 rpm (to establish structure efficiency loss) | |
| No-load rotor N = 31 rpm, 17.1 VDC (generator and gearbox in place) | |
| Load 10 ohm, rotor N1 = 20 rpm, 6.6 VDC | |
| Watt = 4.4 (generator and gearbox efficiency measured separately at 130 rpm generator speed – recorded 0.1) |
| Test results (best of several tests) | Wind 14 m/s (bevel gearbox, ratio 3) |
| No-load rotor N = 370 rpm, 93 VDC | |
| Load 100 ohm, rotor N1 = 255 rpm, 70 VDC | |
| Watt = 49 (generator and gearbox efficiency at 750 rpm generator speed – recorded 0.75) |
Conclusions
- During testing it was established that a gearbox should be a part of the Flow Engine to speed up the generator and boost the voltage and combined torque.
- Electrical efficiency for the prototype based on water speed, current gearbox, etc. is approximately 0.45 (applied to 0.085 for water swept area factor for corrected prototype with counter-rotation). A version without using separating discs was also tried, resulting in a small reduction in performance.
- During testing it was established that about a 50% loss in rpm could be attributed to the structure itself and the gearbox with the generator. This loss is compensated for by providing a 100% absolute rotational speed when compared with the flow speed calculations. The load state normally causes a drop in speed of one-third in driving applications, with a driving force reduction of speed under load (this is expected in engine-generator applications and was used for the Cp calculations above).
- The result of testing established a simplified testing procedure for Flow Engines, as energy producing devices, based on the rpm measurement in a no load condition, then dropping the rpm by one-third to simulate a load, and then recording generator output.
- Similar conclusions apply to both wind and water.
Anatoly Arov is a mechanical engineer with a PhD from a Moscow scientific organisation. He made several inventions in Russia, then emigrated to Canada in 1981 and established the company PIPS (Productivity Improvement and Problem Solving) in 1983. He is now a Canadian citizen, and his inventions in Canada have included a combustion engine, a computer storage device, a DC to AC conversion method and device, Flow Engines, a future car concept and a deep water pressure utilisation method for water energy utilisation). Most of his inventions have been developed to the prototype stage.{/access}
