Introduction
Definition
Wind turbines are devices made up of blade-like propellers referred to as rotors that are used to harness energy from strong winds. These wind turbines are situated on high grounds where the wind is strong to propel the rotors at high speed and in the process convert kinetic energy from the blowing wind to mechanical energy that can be harnessed and used to generate electricity (Kulunk, 2011).
Wind Turbine Blades
The amount of wind energy generated by every single turbine wholly depends on the number of blades, their shapes, and sizes. The longer the blades, the more the energy captured as the blades have a wider surface area exposed to the wind hence increasing their efficiency. Their shapes have also been twisted at an angle to allow for maximum contact with the blowing wind, the angle of inclination should also be in line with the direction of the airflow.
The number of blades is another factor to be considered as the more the rotor blades the higher the efficiency although the recommended maximum number of blades is three per turbine (Liu, 2012). If these blades are not well designed, they may result in high aerodynamic inefficiency, noise pollution, and ground erosion.
Topics of Interest
Aerodynamics
When researching on wind turbines, the aerodynamic field of science is indispensable as it forms the basis of its technical operation in generating electricity from the wind. Aerodynamics is basically a sub-branch of aerospace engineering that entails studying of air molecules in motion and its interaction with solid matter (Ingram, 2011). Wind turbines work under the same principle as the rotor blades interact with the moving air to harness electricity.
To understand the principles under which aerodynamics work, one has to comprehend the force and momentum of the air in motion around an object. When the blades of a wind turbine rotate, they create a laminar flow. The pressure and velocity of wind then suddenly change creating an atmospheric circulation also referred to as turbulence and it is from these commotions that kinetic energy is transformed into mechanical energy that could be used to generate electricity or stored in battery cells. The principles of aerodynamics are also used by structural engineers to determine wind load when constructing tall buildings and bridges (Valencia, 2004).
The Wind
Knowing the fundamental aspects of wind is imperative in the study of the wind turbines. The power harnessed from the wind depends on its flowing speed and that is why the turbines have to be strategically positioned on high grounds where the wind flow is not interrupted by physical features and other obstacles.
Scientist and author Greiner Exova, documented that when the wind velocity is below 10mph then that site is not suitable to install the turbines as that speed cannot generate reasonable amounts of energy. On the other hand, areas with strong gusts were not recommended either as the turbines will be underutilized due to the large energy outputs hence wasting most of the power peaks. He recommended sites with steady light winds which range from a velocity of 20mph to 35mph on average (Exova, 2012).
The wind’s velocity tends to vary every passing minute due to changes in the atmospheric pressure, physical features and weather leading to varying load on the rotors hence the structural and mechanical engineers ought to keep this aspect in mind when constituting and installing the turbines. The technical aspects of engineering should be closely adhered to when constructing these turbines to increase their efficiency and productivity.
A well-designed wind turbine has the potential to capture up to 60% of wind’s power, but if not professionally designed then it may fail to capture most of the wind energy hence professionalism and a lot of technical skills are highly required when it comes to construction of efficient wind turbines (Jonkman, 2003).
Use of Wind Energy by the United Arab Emirates
The wind turbines have remarkably improved the living standards of most people from the Middle Eastern countries by providing a reliable alternative energy source that is readily available, renewable and environmentally friendly. Since most of the land is on a desert that experiences constant wind flow and adequate sunshine, most of the Persian Gulf nations have resolved to harness the renewable energy to supplement energy from fossil fuels.
Wind turbines have been erected at strategic sites to trap the wind energy that now generates up to 30kW of electricity that is used to pump clean underground water to the inhabitants of the Middle East. Role Water Technology has also erected wind turbines and generators to generate sufficient water that is supplied to most of the Arab nations (Exova, 2012).
Reasons for Choosing this Topic
Some of the reasons for settling on this topic of wind energy include:
Wind energy cannot be deleted. As long as the wind blows, one is sure of harnessing the energy. It also reduces the over-reliance on oil as a chief source of energy, for instance, the Middle Eastern nations can now reduce their domestic usage of oil and export most of it as the countries embrace renewable energy sources hence boosting their economy.
Again, wind energy is a clean energy source that is environmentally friendly as opposed to coal and natural gas that have drastic repercussions on the environment, including depletion of the ozone layer (Mendez, 2000). Abu Dhabi has spent over $10 billion in clean-energy with the aim of cutting down on environmental pollution and degradation resulting from the by-products of fuel combustion by vehicles and industries.
This form of renewable energy cannot be depleted hence once installed it will provide energy for generations and generations to come hence cannot be compared to the other forms of energy like coal, petroleum and natural gas that can easily be depleted and that is why the use of wind energy is vital more so to the people of the United Arab Emirates for the sake of the generations to come (Teodoro, 2001).
Conclusion
In conclusion, the structure and design of the wind turbine blades are critical in as far as its ultimate performance is concerned. In order to increase the efficiency of the turbines, their blades have to be professionally designed to effectively trap the wind energy. Glauert designed a Blade Element Momentum (BEM) technique that was used to analyze the performance of the blade and its aerodynamics efficiency. The BEM technique has led to the production of quality wind turbines that have resulted to a paradigm shift in the economy of Arab nations from over-relying on fossil fuel to embracing renewable energy sources (Chult, 2005).
References
Chult, S. (2005, December 28). Calls to utilize renewable energies in the east. The Arabian Business, pp. 1A, 2A.
Exova, G. (2012). Principles for examining efficient wind turbine blades. Power Generation, 149. .
Ingram, G. (2011). Aerodynamics and Loads. Durham: Durham University.
Jonkman, J. (2003). Modelling of the UAE wind turbine for refinement of fast-ad. Colorado: ColeBoulevard Golden.
Kulunk, E. (2011). Aerodynamics of wind turbines. Journal on Fundamental and Advanced Topics in Wind Power, 50, 203-204.
Liu, S. (2012). Development and application of an improved blade momentum method on horizontal axis wind turbines. International Journal of Energy and Environmental Engineering, 3, 30.
Mendez, J. (2000). Wind blade chord and twist angle optimization by using genetic algorithms. Palmas: Las Palmas.
Teodoro, S. (2001). Wind rotor blade construction: Small wind systems for battery charging. London: Department of International Development.
Valencia, U. (2004). Design studies for twist-coupled wind turbine blades. Kansas: Wichita State University.