Research on Ventilation Ontology of Wind Power Vehicle Bai-lin FAN 1,*, Wen-ping XIN 1, Guo-jun DING 2, Jia-qing HUANG 3 and Zeng-hui HUANG 4

Transcription

1 2017 2nd International Conference on Environmental Science and Energy Engineering (ICESEE 2017) ISBN: Research on Ventilation Ontology of Wind Power Vehicle Bai-lin FAN 1,*, Wen-ping XIN 1, Guo-jun DING 2, Jia-qing HUANG 3 and Zeng-hui HUANG 4 1 School of Mechanical Engineering University of Science and Technology, Beijing, , China 2 Shandong, , China 3 Chnagan PSA Automobiles Company, Guangdong, , China 4 Huawu Brake Company, , China *Corresponding author Keywords: Component, Wind power generation, Fluent blades. Abstract. When the car is running in high speed, the energy consumption of the air resistance is responsible for 60%~80% of the total energy consumption. If the energy consumed by windward side is converted into electric energy and stored in the battery, the goal of energy conservation and environmental protection can be achieved. The wind scooper structure to achieve the goal was designed, the software FLUENT is used for numerical simulation of fluid analysis. The best wind scooper structure is determined.the power coefficients of different number of blades are analyzed by using sliding mesh technology of CFD through 2D transient method. Introduction With the popularity of the concept of energy saving, more and more buyers favor new energy vehicles. Many countries around the world are also developing the electric cars[1]. The electric cars have entered the stage of competition in the market. Wind power is renewable energy which is inexhaustible and unlimited. If the wind power produced in the process of driving can be reused and converted into electricity, it will be able to achieve the goal of conservation and environmental protection. Many enterprises have paid attention to the concept of wind power vehicle. Tesla motors which is known for electric vehicles applied for a patent which is a wind power generation device. Through the device, wind power produced by driving is converted into electricity and stored in the battery. Sunday Dispatch reported in 2009 that two American students designed the formula AE conceptual roadster[2],4 vents which turbines are installed inside are installed on the car, the car can increase 20%-25% of electricity. The car Venturi electric designed by Venturi uses solar and wind power to provide energy. With completely controlled by HIMH batteries, the car can travel 50km and the speed can reach 50 km h -1. In China, Beijing Jiaotong University s student Wang Chao designs a device based on vehicle speed and conducts the wind tunnel testing to verify the results[2]. Wang Ran who is working in Huaiyin Institute of Technology designs a centrifugal wind turbine and also chooses the generator and the voltage stabilizing device. Cui Zhihao, studying in Dezhou college, designs small car wind resistance power generation system. Through the generating electric energy testing, they obtain the results that the car running in high speed can generate around 2kwh in 3 hours. Many enterprises apply for the patent of wind power generation devices[3,4]. This paper will design the wind power generation device based on patent practical. Design of Wind Scooper According to the car s body structure and not increase the windward resistance, the device should placed inside the car. Tesla Model S s electromotor is installed on rear axis and the space of

2 mm 600 mm 400 mm under the hood is made room for storage, so the device is placed under the hood. As shown in Figure 1,in consideration of the size of air grid, the inlet of wind scooper is designed initially as 400 mm 100 mm and hexahedral outlet as 100 mm 100 mm followed by semicircular shell radius 100mm. We choose the material: fiber reinforced plastics which is light and hard[2]. The structure s fillet radius for side wall is designed as 0mm, 100mm, 200mm and a kind of plane shape. The software Fluent is used to compare the some points velocities around exit for determining final form. Figure 1. The structure of wind scooper. Figure 2. The structure of wind scooper II. Figure 3. Different speed of the wind scooper near the outlet. Figure 3 displays the velocities of points which side wall radius is 0mm are maximum, but it appears vortex at outlet as Figure 3 shows. The vortex has an effect on coefficient of power which is a direct measure of the efficiency of device in producing energy. It is for this reason that we choose side wall radius 100mm as the wind scooper structure. Blade Design The Choice of Blade Number Different blade shapes of wind turbine get different coefficients of power and electric energy [11]. In this paper, the aerofoil shape chosen is NACA2412 which is usually used in vertical axis wind turbines. Because the flow field calculation is transient, grid element number will reach around 8 million with 3D computational model while there is 300 thousand with 2D model. Therefore for simplification this paper adopts 2D model for analyzing at first and 3D model for testing. As for the choice of blade number,2d incompressible transient analysis is developed to compare coefficient of powers for 3-blades and 4-blades models by sliding mesh technique at various tip speed ratios between 0 and 1. The 2D 4-blades model is shown in Figure 4.Radius of blades is 90mm.The distance is 1200mm from the right boundary to the center of turbine rotation and 1600mm from the upper boundary to the center. Turbulence model chooses RNG k-ε which applies to rotator[12]. Calculating region is divided into rotating region and static region. Figure 4. Streamline of wind scooper's flow field which filet radius is 100 mm. 135

3 The rotating region which radius is 98mm is centered in rotor axis. When meshing, nearby the blades need to proceed local grid refinement and the grid element number is around 300 thousand. Inlet velocity is 15m/s, outlet pressure is 0 Pa[13] and the interface of rotating region and static region is set as interface. The other boundary is set as non-slip wall. SIMPLE algorithm is used to analyze the pressure-velocity coupling calculation with at least 8 periods. Taking the average moment coefficient of several periods and calculating the coefficients of power using the following formulas[14]. By the formulas: C M M V AR (1) M C p A We can obtain: (2) Cp CM (3) where, CM is the coefficient of moment; M is the moment,n m -1 ;ρ is the air density,kg m -3 ;A is the rotor swept area,m 3 ;v is the wind flow velocity,m s -1 ;R is the rotor radius, m;cp is the coefficient of power; is the angular velocity,rad s -1 ; is the tip speed ratio. Figure 5. 2D wind turbine geometry model diagram. Figure 6. Cp of the wind turbine with different blade number. As the Figure 6 shows, the maximum coefficient of power of three-blades structure is at around the tip speed ratio of 0.6.Four-blades structure is at around 0.8,and the latter has the larger value. So we choose the four-blades structure wind turbine. Model Aerodynamic Performance Analysis The following analyzes the influence of wind turbine aerodynamic performance in different tip speed ratios. This section solves the 2D unsteady flow field by sliding meshing method under the transient condition. The meshing and boundary conditions are set the same as above except the different inlet velocity is respectively 15 m s -1 and 25 m s -1 to compare the coefficients of power with different tip speed ratios under different wind speeds. The results of Figure 6 and Figure 7 show the power gotten under the wind speed of 15 m s-1 is lower than power gotten under 25 m s-1,while power curve and the coefficients of power curve is consistent basically. This is because the power is proportional with the cube of the speed and the coefficients of power has nothing to do with the speed. We can also find from the Figure that in the 2D environment, the maximum coefficient of power is gotten when the tip speed ratio is at

4 Figure 7. Power of the different speed ratio under different wind speed. Figure 8. Cp of the different speed ratio under different wind speed. Conclusion 1) To ensure that the speed, the best wind energy utilization and does not produce vortex, radius of 100 mm of the ventilation hood structure was choose finally. 2) 4 blades of wind energy storage appliances than 3 blades of wind energy storage electric wind energy utilization is big, so the four blade wind energy storage electric structure. References [1] The Trends of Science and Technology at Home and Abroad.New Energy Vehicles Abroad Development Situation [J/OL]. Ministry of Science and Technology of the People s Republic of China [ ]. [2] Environmental Protection Concept Roadster Drived by Wind and Solar Power. Solar Energy, 2009, 2: 29. [3] Wang C. Research on Wind Power Generation System Based on Vehicle Speed [Dissertation]. Beijing: Beijing Jia-otong University, [4] Wang R. Design of Wind Generation Device on Electric Vehicle. Automobile maintenance, 2013: 6-7. [5] Cui Z.H., Zhao W.D. Wind Power Generation System Based on Vehicle s Wind Resistance. Internet of Things Technologies, 2015, 5(5): 8. [6] Sun G.M. Petrol-electric Hybrid Vehicle Wind Power Generation Equipment: China Patent, [7] Zhang X.L. wind energy car:china Patent, [8] Huang H.C.A Vehicle Power Generation Technology: China Patent, [9] Liang Y.W. Automobile Wind Turbines: China Patent, [10] Lin S.X, Xue Y.S, Guo L.X, et al. Optimization Design Method of Low Power (Small) Wind Turbine Blades. China High-Tech Enterprises, 2015, 23(8): [11] Stavros A. Papathanassiou, Michael P. Papadopoulos. Dynamic Characteristics of Autonomous Wind Diesel System. Renewable Energy, 2001, 23:

5 [12] Hui W.X. Analysis on Aerodynamic Performance and Optimization Design of Vertical Axis Wind Turbine [Dissertation]. Beijing: North China Electric Power University, [13] Zhao W. Research on the Characteristics of Low Wind Speed Startup Vertical Axis Wind Turbine [Dissertation]. Yun-nan: Kunming University of Science and Technology, [14] Jin X.H. The Prediction of Aerodynamic Performance on Straight-bladed Wind Turbine [Dissertation]. Shanxi: Xi'an University of Technology,