Soft-bionic-fishtail structured triboelectric nanogenerator driven by flow-induced vibration for low-velocity water flow energy harvesting

To adapt to the low-velocity water flow closely related to human life,the natural energy can be efficiently harvested and used to power monitoring devices.Herein,a triboelectric soft fishtail(TE-SFT)driven by flow-induced vibration(FIV)effect is proposed based on the soft material synthesis technology.Specifically,inspired by the fishtail fin,a bluff body with the cross-section of fishtail-shaped is designed,and has a preferable vortex effect by fluid simulation.In power generation part,the triboelectric nanogenerator(TENG)is designed to act as an inertial pendulum structure by geometric method.Under the FIV effect,the TESFT driven by fishtail-shaped bluff body swings like a fish in the water and then brings the inertial pendulum to acquire the oscillation for harvesting energy from low-velocity water flow.The TE-SFT attains an open-circuit voltage(VOC)of 200 V to 313 V at the flow velocities of 0.24 to 0.89 m/s.Additionally,after 30 days of water immersion,the VOC of TE-SFT retains 96.81%.In demonstration,the TE-SFT is applied to power the temperature and humidity sensor through harvesting water flow energy.This work also provides a way for self-powered system based on the TENG and soft bionic fish in water environment.

3D fully-enclosed triboelectric nanogenerator with bionic fish-like structure for harvesting hydrokinetic energy

The hydrokinetic energy of river current,as one of the essential and widespread renewable energies,is difficult to be harvested in low flow velocity and shallow water areas.In this work,a three-dimensional(3D)fully-enclosed triboelectric nanogenerator(FETENG)with bionic fish-like structure for harvesting hydrokinetic energy is reported,which is comprised of the triboelectric powergeneration unit,bionic fish-like structure and connection unit.Through the bionic structure,the FE-TENG realizes zero head power generation in shallow water with low flow velocity.What’s more,the effect of external excitations and bionic structures on the electrical performance are systematically studied in this work.The FE-TENG can generate peak power density of 7 and 0.36 W/m^(3)respectively under the simulated swing state with frequency of 1.25 Hz and simulated river current with flow velocity of 0.81 m/s.In practical applications,due to the 3D fully-enclosed design,the FE-TENG immersed in water for 35 days demonstrates excellent immersion durability with undiminished electrical performance.Therefore,the work proposes an efficient method realizing zero head power generation,and provides a good candidate for long-term service in the river current.

Effect of cooperative injection and suction jet on power extraction characteristics of a semi-active flapping airfoil

A novel cooperative injection and suction jet was employed in this work to improve the power extraction characteristics of a semi-active flapping airfoil(S-AFA).The combined Taguchi method and numerical simulations was used to optimize the characteristic parameters of the cooperative injection and suction jet that affect the power extraction characteristics of the S-AFA.Under the Reynolds number of 6×10^(4)and the pitching axis location at the center of the ellipse airfoil,the effects of jet position,jet width,jet coefficient as well as phase difference between the cooperative injection and suction jet and the active pitching motion on the power extraction characteristics of the S-AFA are systematically examined.It is concluded that the power extraction characteristics of the S-AFA can be enhanced by employing cooperative injection and suction jet.Compared to the S-AFA without jet,the maximum efficiency is increased 11.06%for the S-AFA with optimized cooperative injection and suction jet.The flow structure behavior analysis shows that the vortex strength,the low pressure range in the suction surface of the airfoil as well as the pressure value in the pressure surface of the airfoil are increased due to the cooperative injection and suction jet,and it is why the power extraction characteristics of S-AFA can be improved.