As the world's largest wind power installation country, China has a cumulative installed capacity of more than 200GW. In the early stage of wind power projects, wind farm income is low or even loss due to inaccurate wind measurement data, decline of wind resources, site selection deviation and other issues.
he blade winglet wind turbine power increase and efficiency improvement project are a Sino-British cooperation project from the University of Oxford technical team introduced by Tus Sino-British Marine Science and Technology Research Institute. It is a comprehensive application of advanced aerodynamics, fluid mechanics, composite materials and other technologies to wind turbine tips. It can greatly reduce the cost of wind power when the wind power industry is restricted by the quality assurance of a large number of wind turbines, the decline in feed-in tariffs, and the reduction of subsidies, which play a key role in help companies maintain profit growth and achieve victory in parity competition.
Compared with other power increasing technologies, the wind turbine blade winglet technology involved in the project has the advantages of low cost, higher efficiency, and simple and convenient installation. It is currently the only application of blade double winglets technology in practice and has passed the technical verification. At present, this field is a blank area for domestic blade manufacturers.
In order to improve efficiency and reduce the aerodynamic loss caused by the tip vortex, winglet technology is widely used in modern aircraft design. It can effectively prevent the vortex at the tip of the wing, improve the lift-drag ratio, and achieve the purpose of increasing lift. At present, winglets are mainly divided into two categories, one is single-stage (such as Boeing 747-400), and the other is upper and lower two-stage (such as Airbus A310-300, A-380, Boeing 737).
A camber angle is usually designed for a single segment winglet to bring additional lift to the aircraft, but it also brings large additional bending moment to the wing root. Sometimes, the two-stage winglet is also called vortex diffuser. This kind of winglet focuses on blocking and separating the vortex. It is usually perpendicular to the main wing surface and does not generate additional lift. Therefore, it will not bring additional bending moment. This kind of winglet has no high requirements on the wing structure.
Based on the aerodynamic theory, the blades of wind turbines are very similar to the wing, so the vortex loss of the wing tip is also very similar to that of the blade. In order to compensate for the loss of aerodynamic performance of the blade caused by the loss of the tip, it is also possible to increase the blade winglet to change the airflow distribution through the tip area and improve the power generation efficiency. The tip of the blade is the farthest from the center of the hub, and the loss of torque is greater, so it is very important to reduce the loss of the tip.
Leaf blower torque loss is bigger
The project will comprehensively apply advanced aerodynamics, fluid mechanics, composite materials and other technologies to mass-produced wind turbine blades and new technology blades suitable for offshore installation and has launched blade winglet for Chinese wind turbines.
Tus - Aero blade tip winglet CFD simulation
The tip winglet on the project by CFD simulation, the tip of the blade can smoothly through the air, airflow direction deviation is very small, can effectively reduce the blade tip vortex, blade power generation efficiency. And can according to the actual circumstance of blade, design tip winglet with different length.
Tip winglet with different length
3. Creative value
Take the 2017 project partner Anakata Wind Power Resources (UK) Ltd.’s 900KW-61m wind wheel diameter wind turbine installation test at EWT in the Netherlands as an example.
Without increasing the length of the blades, the relevant test results were obtained through three-month data collection of two wind turbines with and without winglets. The effective wind measurement data is in the region of 260-307deg, which shows that the annual wind power generation of wind turbine increases by 4.4% between cut in wind speed and rated wind speed.
The Netherlands 900 kw test fan test data
In November 2019, the "blade double winglets" power augmentation module installation demonstration project was successfully completed in a wind farm in Gansu. In this demonstration project, a total of two 1.5MW units were selected for demonstration prototype modification, and 2 adjacent units were selected for comparative inspection. The installation time was only 4 days and the test time was 6 months. This technology has the characteristics of high installation safety factor, short on-site construction period, and light weight of the blade extension. It is an innovative aerodynamic attachment device for increasing power and efficiency of wind turbines. It is the first domestic wind turbine “blade double winglets” power increasing component installation project.
In December 2019, the AN08 new vortex generator designed by the project technical team was installed in the Mingyang 1.5MW wind turbine unit of Hainan Wind Farm. According to the actual operating conditions, the unit used CFD to simulate and design the installation position of the vortex generator. Through theoretical calculations, the AN08 new vortex generator unit installed this time can increase the annual power generation of the wind turbine by at least 2%.
In September 2019, Anakata Wind Power Resources (UK) Ltd signed a formal agreement to establish a joint venture company with Beijing Tus-Wind Technology Co., Ltd. and Shandong TUS–ORE Catapult Research Centre (TORC). In June 2020, the registration process of the joint venture company landing in Yantai high tech Zone has been completed.