scholarly journals An Analysis Method for Capacitive Micromachined Ultrasound Transducer (CMUT) Energy Conversion during Large Signal Operation

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 876 ◽  
Author(s):  
Amirabbas Pirouz ◽  
F. Degertekin
Keyword(s):  
Energy Conversion ◽  
High Efficiency ◽  
Linear Time ◽  
Mechanical Energy ◽  
Ultrasound Transducers ◽  
Coupling Coefficients ◽  
Large Signal ◽  
Membrane Geometry ◽  
Ultrasound Applications ◽  
Drive Signals

With Capacitive Micromachined Ultrasound Transducers (CMUTs) increasingly being used for high intensity, large signal ultrasound applications and several drive methods being proposed, the efficiency of these devices in this operation regime have not been quantitatively evaluated. Since well-known frequency and capacitance-based coupling coefficients definitions are not valid for large signal, nonlinear operation, an energy-based definition should be used. In this paper, an expression for mechanical energy in a CMUT is obtained based on the assumption that CMUT is a linear time varying capacitor in all regimes of operation. This expression is evaluated by the help of an experimentally verified nonlinear CMUT model to define an energy conversion ratio (ECR) which can be considered as a coupling coefficient valid for all regimes of operation. This parameter is validated in the small signal regime and then used to evaluate CMUT performance with various large drive signals. The quantitative modeling results show that CMUTs do not need DC bias to achieve high efficiency large signal transduction: AC only signals at half the operation frequency with amplitudes beyond the collapse voltage can provide efficiencies (ECR) above 0.9 with harmonic content below −25 dB. Based on these results, ECR variation with membrane geometry and parasitic capacitance are given as examples for device optimization. The overall modeling approach is also qualitatively validated by experiments.

The Dimension Match and Parameters Setting of the Hydraulic Motor for the Hydraulic-Electromagnetic Energy-Regenerative Shock Absorber

2017 ◽  
Author(s):  
Jia Mi ◽  
Lin Xu ◽  
Sijing Guo ◽  
Mohamed A. A. Abdelkareem ◽  
Lingshuai Meng ◽  
...  
Keyword(s):  
Energy Conversion ◽  
Shock Absorber ◽  
High Efficiency ◽  
Mechanical Energy ◽  
Hydraulic Cylinder ◽  
Electromagnetic Energy ◽  
Operating Conditions ◽  
Hydraulic Motor ◽  
Wide Range ◽  
Regenerative Shock Absorber

Hydraulic-electromagnetic Energy-regenerative Shock Absorber (HESA) has been proposed recently, with the purpose of mitigating vibration in vehicle suspensions and recovering vibration energy traditionally dissipated by oil dampers simultaneously. The HESA is composed of hydraulic cylinder, check valves, accumulators, hydraulic motor, generator, pipelines and so on. The energy conversion from hydraulic energy to mechanical energy mainly depends on the hydraulic motor between two accumulators. Hence, the dimension match and parameter settings of hydraulic motor for the HESA are extremely important for efficiency of the whole system. This paper studies the methods and steps for dimension matching and parameter settings of the hydraulic motor in a case of a typical commercial vehicle. To evaluate suspension’s vibration characteristics, experiments on the target tour bus have been done. Simulations are conducted to investigate the effects of the hydraulic motor in different working conditions. The simulation results verify that the methods and steps adopted are accurate over a wide range of operating conditions and also show that appropriate matching and parameter settings of the hydraulic motor attached in the HESA can work with high efficiency and then effectively improving energy conversion efficiency for the whole system. Therefore, the theory of the matching progress can guide the future design of an HESA.

scholarly journals Performance Characteristics in Runner of an Impulse Water Turbine with Splitter Blade

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 303
Author(s):  
Lingdi Tang ◽  
Shouqi Yuan ◽  
Yue Tang ◽  
Zhijun Gao
Keyword(s):  
Energy Conversion ◽  
Flow Direction ◽  
Mechanical Energy ◽  
Experimental Tests ◽  
High Energy ◽  
Negative Energy ◽  
Water Turbine ◽  
Conversion Performance ◽  
Water Turbines ◽  
Current Energy

The impulse water turbine is a promising energy conversion device that can be used as mechanical power or a micro hydro generator, and its application can effectively ease the current energy crisis. This paper aims to clarify the mechanism of liquid acting on runner blades, the hydraulic performance, and energy conversion characteristics in the runner domain of an impulse water turbine with a splitter blade by using experimental tests and numerical simulations. The runner was divided into seven areas along the flow direction, and the power variation in the runner domain was analyzed to reflect its energy conversion characteristics. The obtained results indicate that the critical area of the runner for doing the work is in the front half of the blades, while the rear area of the blades does relatively little work and even consumes the mechanical energy of the runner to produce negative work. The high energy area is concentrated in the flow passage facing the nozzle. The energy is gradually evenly distributed from the runner inlet to the runner outlet, and the negative energy caused by flow separation with high probability is gradually reduced. The clarification of the energy conversion performance is of great significance to improve the design of impulse water turbines.

Power Harvesting from the Vibration-Induced by the Piezoelectric Stator of Traveling Wave Rotary Ultrasonic Motor

2011 ◽  
Vol 317-319 ◽  
pp. 616-620 ◽  
Author(s):  
Guang Qing Wang ◽  
Zhong Wei Zhao
Keyword(s):  
Energy Conversion ◽  
Analytical Model ◽  
Traveling Wave ◽  
Mechanical Energy ◽  
Ultrasonic Motor ◽  
Maximum Output ◽  
Induced Voltage ◽  
Power Harvesting ◽  
Conversion Model ◽  
The Relationship

In this article, a novel electro-mechanical energy conversion model of power harvesting from the vibration-induced the piezoelectric stator of the traveling wave rotary ultrasonic motor was proposed. Based on the curvature basis approach, the relationship between the deduced voltage and the mechanical stain induced by piezoelectric polarization was formulated. In addition to the relationships between the maximum induced voltages at the resonance frequency, the conversion energy density and the dimensions of the piezoelectric stator were also derived. The analytical model shows that the vibration-induced voltage is proportional to the exciting electrical voltage magnitude and square of height of the piezoelectric ceramic (PZT) but is inversely proportional to the permittivity of PZT and the damping coefficient of the stator. Some simulations and experimental results demonstrate that the maximum output voltage coincides with the energy conversion analytical model.

Non-native Co-, Mn-, and Ti-oxyhydroxide nanocrystals in ferritin for high efficiency solar energy conversion

2014 ◽  
Vol 26 (1) ◽  
pp. 015703 ◽  
Author(s):  
S D Erickson ◽  
T J Smith ◽  
L M Moses ◽  
R K Watt ◽  
J S Colton
Keyword(s):  
Solar Energy ◽  
Energy Conversion ◽  
High Efficiency ◽  
Solar Energy Conversion

scholarly journals Metamaterial Receivers for High Efficiency Concentrated Solar Energy Conversion

2016 ◽  
Author(s):  
Julius E. Yellowhair ◽  
Hoyeong Kwon ◽  
Andrea Alu ◽  
Robert L. Jarecki ◽  
Subhash L. Shinde
Keyword(s):  
Solar Energy ◽  
Energy Conversion ◽  
High Efficiency ◽  
Solar Energy Conversion ◽  
Concentrated Solar Energy

Innovative Design of the Wind-Driven Efficient Feeding Mechanism

2013 ◽  
Vol 274 ◽  
pp. 290-293
Author(s):  
Bao Gang Wang ◽  
Qi Hui Song ◽  
Guang Chi Xu
Keyword(s):  
Energy Conversion ◽  
High Efficiency ◽  
Transmission Mechanism ◽  
Linkage Mechanism ◽  
Innovative Design ◽  
Feeding Mechanism ◽  
Gear Mechanism ◽  
Actual Operation ◽  
The Common ◽  
Material Transportation

A wind-driven feeding mechanism of high efficiency is designed according to the TRIZ theory and its mechanical structure innovative design based on the principle of energy conversion. It aims at delivering of small granular, cylindrical, flakes and other materials in machinery, pharmaceuticals, electronics and other industries by transmission mechanism such as the typical gear mechanism and linkage mechanism. The prototype is produced combined with the specific parameters of the common materials. The modular innovative design is adopted, including the transmission module, driver module and material feeding module. By the inspection of the actual operation, each design module of the produced prototype is stable and reliable. At the same time the effect of material transportation is good.

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