Wind Turbine Generation System (WTGS) is a vehiclemounted wind turbine system that is used to generate electricity. This paperfocuses on designing a horizontal axis wind turbine and simulating itsperformance and showing its output results. This paper shows power extracted bythe turbine from the wind and its different parameters (attack angle, dragco-efficient, wind speed) relation with extracted power. It’s assumed thatthere is no external air flow. Thus vehicle speed is assumed to be air speed.And if there is any external air flow, it will be added to the air velocity.
Values of some constants like Mach number, Reynolds number, Ncrit areconsidered for a certain testing environment. Keywords: Wind energy, wind turbine, electric vehicle,power, simulationIntroductionRenewable energy sourcesoffer limitlessresource and environment friendly operation comparedtoconventional energy sources. There are several forms ofrenewable energy suchas solar energy, wind energy,geothermal energy, tidal energy, hydro energyandbioenergy.However, wind energy is the most valuable, safe and fastestgrowing renewable energy. At the end of2016, wind energy has servedapproximately 49%electricity of South Australia (GWEC, 2017). Moreover, it islow cost(0.12/kWh) (Ravi et al.
, 2009), low carbon footprints (<5CO2/kWh), minimum soundpressure level (50-60 dBfrom 100 feet) and easy integration with other energysources. However, commercial wind turbine (WT) is notsuitable for small scaleapplication as it requires big land,high installation cost, lack of energystorage and notportable. Additionally, in some places wind speed isnotsufficient to run a commercial or domestic WT.
Hence, amodified WT system isnecessary which can be efficientunder this kind of circumstances. Consequently,the ideaof mobile WT for vehicle came along for small scaleenergy harvesting(Christian, 1975). Several attempts are taken to produce electricity by vehicleas a number of literatures are already exists (Sham, 2011; Ferdouset al., 2011). However, theseproposals never meet the threshold of the practicalimplementation.
In mostcases, these proposed modelseither too inefficient or directly affect theaesthetic appeal of the vehicles (Jean, 1983; Jose, 2013; Cecil, 2012;Andrew,2013; Peter, 2013; Keith, 1979; Tran, 2011). Therefore, electricity harvestingfrom vehicle is still an active area to explore. From these motivations, thispaper proposes amodified, portable and distributed wind turbine system forvehicles. It is possible to increase the incoming wind speed for a mounted WTartificially by using the vehicle speed.Wind energy and powerWind energy is availablein the form of kinetic energy which can be transformed to energy by mechanicalconversion. As it is required to use wind energy to produce electrical energy,hence the conversion is mainly from the mechanical to electrical.
So the windis the primary source of energy and it is different from usual wind turbine asit will be mobile. The kinetic energy in wind can be expressedby, (1)Here V is the speed of air,? is the air density, A is the area of the air parcel and T is the time needed for airparcel to move through the plane. Now wind power can be expressed as Pw = (2)For the cross sectional area the available wind powerPw= (3)The power captured by wind is as followPout=Cp Pin (4)Here Pout is the actualoutput captured by the wind turbine, Cpis the powerco-efficient and Pinpower flows through the wind turbine. Thepower co-efficient represents a fraction of power captured by the wind turbineand has a theoretical maximum of 0.
55(David Richard et al 1993). The powerco-efficient can be expressed by a typical formulaas (5)Here ?is the tip speed ratio of the wind turbine and ? is the pitch angle of theblade.The tip speed ratio ? can be expressed as (6)Here ? is the angular velocity ofturbine. This is our proposed model of electric vehicle with the diffusershroud augmented turbine. A diffuser shroud is used as it increases the windspeed at the rotor plane. Thus greater generated power for the same air speedfor the turbine having shroud. According to velocity distribution around a movingcar, the velocity distribution of air is highest at the top of theroof. And at the front top, its highest.
Two turbines are used only for morepower generation purpose. Description of the Different Elements Used in the VMWT System:Horizontal Axis WindTurbine (HAWT):Horizontalaxis wind turbines are the most common type used. All of the components(blades, shaft, and generator) are on the top of the tower, and the blades faceinto the wind. In case vehicle there is no tower. The shaft is horizontal tothe ground.
The wind hits the blades of the turbine that are connected to ashaft causing rotation. The shaft has a gear on the end which turns a generator(sometimes there is no gear; just the shaft is connected directly with thegenerator). The generator produces electricity and sends the electricity intothe power grid (in our case DC generator is used and the produced power issaved into battery). The wind turbine also has some key elements that add toefficiency. Inside the Nacelle is an anemometer, wine vane and controller thatread the speed and direction of the wind (in our case direction of the vehicleis considered as the direction of the air).
In case of extreme winds theturbine has a break that can slow the shaft speed and/or isolate the shaft fromthe generator. This is to inhibit any damage to the turbine or generator inextreme conditions Rotor:Rotor collectsenergy from the wind. The rotor consistsof two or more blades which rotateabout an axis (horizontal or vertical).Rotational speed of the rotor isdetermined by the wind speed and the shape of the blades.
The blades areattached to the hub, which in turn isattached to the main shaft. So rotor isconsists of hub and blades.Description of the Turbine:1.
Airfoil:An airfoil or aerofoil is the shape of a wing, blade (of apropeller, rotor, or turbine), or sail as seen in the cross section. That isairfoil is the cross sectional curve of the turbine blade. The lift on anairfoil is primarily the result of its angle of attack and shape. When orientedat a suitable angle, the airfoil deflects the oncoming air, resulting in aforce on the airfoil in the direction opposite to the deflection.
This force isknown as aerodynamic force and can be resolved into two components: lift anddrag. The lift component is responsible for the rotation of the turbine. Airfoil design is major part in turbine designing.
NACAdeveloped some airfoils. The NACA airfoils are airfoil shapes developed by theNational Advisory Committee for Aeronautics (NACA). The shape of the NACAairfoils is described using a series of digits following the word “NACA”.Several types of NACA airfoils are: Four-digit series, Five-digit series,1-series, 6-series, 7-series, and 8-series.We used NACA 2412 airfoil. The airfoil has a maximum camber of2% located 40% (0.
4 chords) from the leading edge with a maximum thickness of12% of the chord.From Fig 4, we can see with increase in angle of attack alpha (?), liftcoefficient Cl increases up to a certain point. Then it decreases. And from Fig5, drag coefficient Cd decreases with increase in alpha (?).From Fig 6, wecan see angle of attack of around 8 degree is optimum where Cl/Cd has a highestvalue. So angle of attack of 8 degree should be maintained. 2.
Blade design:We used QBlade v0.963 to primarily design the blade and simulateits performance. We assumed Reynolds number 50000, Mach number 0, Ncrit 9 and air density (?) 1.225 kg/m3.Blade in designed for simulation in QBlade:From Fig 9, we see for a rotational speed of around 1200 rpm theblade can extract highest power; about 60 W from the wind. From Fig 10, we seewith increase in TSR, power co-efficient Cp increases at a certain point andthen decreases.
In this case optimum TSR is 4.5.ConclusionsA convenient system for energy harvestingfrom wind to charge the battery of the electric vehicle is proposed in thispaper. The architecture and the design of the wind turbine have been discussedin detail. The wind turbine mounted in the electric vehicles have manyattractive features including increasing rpm and torque compared to theconventional vehicles, along light weight, small size and easy to install. Fromexperiment the wind turbine mounted on the vehicle can produce 200W (at speedof 80Km/h) with proper conversion technology it can be stored for future use.Nevertheless, it produces some drag force which is the great challenge in thisfield.
Moreover, this wind turbine can be used for producing electricity insmall scale for electrical vehicles or some house hold. Introducing hybrid caris a great future agenda. Brief Description of Designand Analytical ApproachConventionalelectrical vehicles have the problem with charging because the charging anddischarging time are equal to each other. So if only the vehicle could becharged in its motion state that would be a great alternative for the chargingof electric vehicles. The wind energy is a great source of energy and the speedof vehicle will produce a great deal of wind which can be used to produceelectrical energy.
This research paper proposes a design of wind turbine toproduce electrical energy to charge the battery of electric vehicles duringmotion and an algorithm to get optimum power for charging the battery of thevehicles.