Low temperature environment brings to the blade and the fan are the serious test, single for blade, blade icing problem caused by low temperature environment, material and structure of the performance change, load change problems, etc., all we need to have a better solution and more detailed design considerations. This review focuses on translation is now a worldwide difficult problem in the field of wind power, namely the low temperature environment of the blade icing problem is discussed.
Coastal and inland areas where is easy to install, such as three north areas has been full of fan, the fan in the south and the mountain of installed, sea fan also mostly in research and development stage is not larger mass. On the other hand, the existing fan drum tower height, so even in coastal areas, winter a lot of fan will touch with low clouds. Sea large size will be what kind of ice blades, due to a lack of a better measuring method and the necessary information, it is not clear.
Inland areas, especially in mountainous areas, the large size fan during operation and outage will be affected by the icing problems. Although the early consider the fan of ice, commissioning when installed with special sensor heating deicing system and corresponding supporting facilities, accumulated certain experience. Yet on the market, however, there is no mature and standardized fan appear at low temperature. Discussed in this paper, and the low temperature freezing problems and their solutions, aimed at different low-temperature environment demand for deicing system presents the corresponding guidance.
1, the influence of low temperature on fan design. Low temperature factors affect the design of the fan: in many ways and ice cream, and pneumatic air density at low temperatures to rise to fan has a significant impact, affecting the load of the fan and power output. Low temperature will lead to large blade attached quality of ice, which will change the frequency of the fan blade, and then change the dynamic response behavior. At the same time, the control system will also be affected. Due to freezing changed blade aerodynamic shape, leading to the blade stall than expected in advance or delay the design. The electric or hydraulic variable propeller control corresponding configuration should be changed. Blade icing can lead to a detection signal of the fan system failure and feedback error signal. Extreme low temperature fan parts need to change the material, such as the commonly used steel will become fragile.
Fan itself running safety and the safety of the surrounding environment will be affected by cold or icy. Fan thrown at runtime or drops of ice ice fragments may harm the fan near the people or things. Fan is the integrity of the structure itself also will be affected by the imbalance of freezing blade or the influence of asymmetry. Due to the ice changed the fan parts may cause resonance frequency, the fatigue load of fans also increases. Rising air density may increase the load and the maximum power output. If fan could not automatic reaction, motor may burn out or transmission chain, gear box may overload or damage.
Some wind power project of economy will be affected by the low temperature environment, especially more potential to freeze in the region. Do fan project planning in these areas, to require types and predict freezing period, need to understand the power output and downtime due to freezing to predict the temperature spectrum distribution associated with wind conditions. If necessary, may exist currently IECI - class IV wind conditions fails to cover a specific wind conditions at low temperature, special definition needs to be done. Specific working condition of low temperature fan may require a specific device, such as need the blades, gear box, circuit boards and other components to consider heating components, USES apply low temperature steel, using the heat of the vane anemometer and freezes or specific sensor. Even it is necessary to take into account in the planning stages and economy evaluation and settlement under low temperature the specific needs of maintenance and repair. Low temperature environment to maintenance staff to reach a certain position of wind opportunity big difficulties, leading to higher transportation costs. At the same time, if the road ice or snow for a long time, can lead to installed, normal operations can't affecting electricity.
The anemometer heated the measurements there may be a problem, not the anemometer heated the extreme wind speed measurements may be low, especially in the alpine region freezing period. Can be divided into the ice-free the icing situation in different areas of the ice, ice is less or frequent three types. But that, too, just took the first step on the accurate evaluation to the low temperature environment.
Due to security issues, in some parts of the laws and regulations may access to one ticket veto a wind power project.
2, how to detect low temperature freezing conditions. How to define the specific areas of low temperature environmental factors? In addition to standard measurements, environmental factors such as pressure, temperature, humidity, still need to consider cloud height and the water vapor content. But these additional factors usually do not in some areas it is recorded in the record, so you need to look for other ways to get to know the region of ice.
