scholarly journals Hybrid Cell Structure for Wideband CMUT: Design Method and Characteristic Analysis

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1180
Author(s):  
Hongliang Wang ◽  
Xiao Huang ◽  
Lijun Yu ◽  
Qi Ding ◽  
Hanqiang Zhang ◽  
...  
Keyword(s):  
Design Method ◽  
Structural Parameters ◽  
Cell Structure ◽  
Ultrasonic Transducer ◽  
Hybrid Cell ◽  
Characteristic Analysis ◽  
Cell Spacing ◽  
Capacitive Micromachined Ultrasonic Transducer ◽  
Design Requirements ◽  
Selection Of

Capacitive micromachined ultrasonic transducer (CMUT) is an ultrasonic transducer based on the microelectromechanical system (MEMS). Wideband CMUT has good application prospects in ultrasonic imaging, ultrasonic identification, flow measurement, and nondestructive testing due to its excellent characteristics. This paper studies the method of increasing the bandwidth of the CMUT, proposes the structure of the wideband CMUT with a hybrid cell structure, and analyzes the design principles and characteristics of the wideband CMUT structure. By changing the cell spacing and the number of cells of different sizes composing the CMUT, we analyze the simulation of the effect of the spacing and number on the CMUT bandwidth, thereby optimizing the bandwidth characteristics of the CMUT. Next, the selection principle of the main structural parameters of the wideband CMUT is analyzed. According to the proposed principle, the CMUT in the air and water are designed and simulated. The results prove that both the air and water CMUT meet the design requirements. The design rules obtained in this paper can provide theoretical guidance for the selection of the main structural parameters of the wideband CMUT.

scholarly journals Investigation on Design Theory and Performance Analysis of Vacuum Capacitive Micromachined Ultrasonic Transducer

Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1127
Author(s):  
Xiao Huang ◽  
Hongliang Wang ◽  
Lijun Yu
Keyword(s):  
Influencing Factors ◽  
Design Theory ◽  
Structural Parameters ◽  
Cell Structure ◽  
Ultrasonic Transducer ◽  
Simulation Software ◽  
Performance Parameters ◽  
Element Simulation ◽  
Capacitive Micromachined Ultrasonic Transducer ◽  
And Performance

The capacitive micromachined ultrasonic transducer (CMUT), as a new acoustic-electric conversion element, has a promising application prospect. In this paper, the structure of the vacuum capacitive micromachined ultrasonic transducer is presented, and its performance-influencing factors are investigated. Firstly, the influencing factors of the performance parameters of the vacuum CMUT are analyzed theoretically based on the circular plate model and flat plate capacitance model, and the design principles of the structural parameters of the CMUT cell are proposed. Then, the finite element simulation software COMSOL Multiphysics is used to construct CMUT cell models with different membrane materials, membrane shapes, membrane radius thicknesses, and cavity heights for simulation verification. The results show that both the membrane parameters and the cavity heights affect the performance parameters of the Vacuum CMUT. In order to improve the efficiency of the CMUT, materials with low bending stiffness should be selected, and the filling factor of the membrane should be increased. In order to achieve high-transmission sound pressure, a smaller radius thickness and a larger cavity height should be selected. To achieve high reception sensitivity, a larger membrane radius thickness and a smaller cavity height should be selected. In order to obtain high fractional bandwidth, a larger membrane radius thickness should be selected. The results of this paper provide a basis for the design of Vacuum CMUT cell structure.

Design and Simulation of Aero-Engine Combination Vortex Fuel Pump

2014 ◽  
Vol 568-570 ◽  
pp. 1785-1789
Author(s):  
Jiang Feng Fu ◽  
Hua Cong Li ◽  
Jia Li ◽  
Shu Hong Wang
Keyword(s):  
3D Model ◽  
Design Method ◽  
Simulation Optimization ◽  
Structural Parameters ◽  
Empirical Coefficient ◽  
Vortex Pump ◽  
Aero Engine ◽  
Design Requirements ◽  
Booster Pump ◽  
Coefficient Method

To solve the problem that single stage booster pump has the problem of low oil pressure at low speed condition. Paper gave a design method for three stage combination vortex pump which uses radial series. The preliminary structural parameters of the vortex pump were designed by using the empirical coefficient method. Then Hex/Wedge grid is used to generate mesh for the established 3D model of the vortex pump. The final structure parameters were obtained by CFD numerical simulation optimization iterately. Finally, the flow field of combination vortex pump was analyzed. Simulation results show that: The combination vortex pump meet the design requirements.

Research on New Strucural Aero Fuel Centrifugal Pump Design

2014 ◽  
Vol 568-570 ◽  
pp. 1801-1807
Author(s):  
Jia Li ◽  
Hua Cong Li ◽  
Jiang Feng Fu ◽  
Shu Hong Wang
Keyword(s):  
Centrifugal Pump ◽  
Block Structure ◽  
Design Method ◽  
Simulation Optimization ◽  
Structural Parameters ◽  
Empirical Coefficient ◽  
Pump Design ◽  
Design Requirements ◽  
Hybrid Grid ◽  
Coefficient Method

A inducer and impeller combination aero fuel centrifugal pump design method was given. Based on empirical coefficient method the preliminary structural parameters of the combination Centrifugal pump were designed firstly. Then the Centrifugal pump Hybrid Grid model was built with muti-block structure and octree style.The final structure parameters were obtained by CFD numerical simulation optimization. Finally, the flow field of combination Centrifugal pump was analyzed and compared simulation datas with test datas by making the test samples.The relative error of the design point doesn’t exceed 5%, indicates that the inducer and impeller combination pump meet the design requirements.

Design and Experiment of Capacitive Micromachined Ultrasonic Transducer Array for High-Frequency Underwater Imaging

2020 ◽  
Vol 13 ◽  
Author(s):  
Yuanyu Yu ◽  
Jiujiang Wang ◽  
Xin Liu ◽  
Sio Hang Pun ◽  
Weibao Qiu ◽  
...  
Keyword(s):  
Ultrasound Imaging ◽  
High Frequency ◽  
Ultrasonic Transducer ◽  
Center Frequency ◽  
Design Parameters ◽  
Underwater Imaging ◽  
Release Process ◽  
Steel Wires ◽  
Capacitive Micromachined Ultrasonic Transducer ◽  
Frequency Ultrasound

Background:: Ultrasound is widely used in the applications of underwater imaging. Capacitive micromachined ultrasonic transducer (CMUT) is a promising candidate to the traditional piezoelectric ultrasonic transducer. In underwater ultrasound imaging, better resolutions can be achieved with a higher frequency ultrasound. Therefore, a CMUT array for high-frequency ultrasound imaging is proposed in this work. Methods:: Analytical methods are used to calculate the center frequency in water and the pull-in voltage for determining the operating point of CMUT. Finite element method model was developed to finalize the design parameters. The CMUT array was fabricated with a five-mask sacrificial release process. Results:: The CMUT array owned an immersed center frequency of 2.6 MHz with a 6 dB fractional bandwidth of 123 %. The pull-in voltage of the CMUT array was 85 V. An underwater imaging experiment was carried out with the target of three steel wires. Conclusion:: In this study, we have developed CMUT for high-frequency underwater imaging. The experiment showed that the CMUT can detect the steel wires with the diameter of 100 μm and the axial resolution was 0.582 mm, which is close to one wavelength of ultrasound in 2.6 MHz.

scholarly journals An Investigation of Silica Aerogel to Reduce Acoustic Crosstalk in CMUT Arrays

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1459
Author(s):  
Varshitha Yashvanth ◽  
Sazzadur Chowdhury
Keyword(s):  
Silica Aerogel ◽  
Ultrasonic Transducer ◽  
Fluid Interface ◽  
Fractional Bandwidth ◽  
Neighboring Element ◽  
Element Analysis ◽  
Average Improvement ◽  
Capacitive Micromachined Ultrasonic Transducer ◽  
Scholte Wave ◽  
Fea Simulation

This paper presents a novel technique to reduce acoustic crosstalk in capacitive micromachined ultrasonic transducer (CMUT) arrays. The technique involves fabricating a thin layer of diisocyanate enhanced silica aerogel on the top surface of a CMUT array. The silica aerogel layer introduces a highly nanoporous permeable layer to reduce the intensity of the Scholte wave at the CMUT-fluid interface. 3D finite element analysis (FEA) simulation in COMSOL shows that the developed technique can provide a 31.5% improvement in crosstalk reduction for the first neighboring element in a 7.5 MHz CMUT array. The average improvement of crosstalk level over the −6 dB fractional bandwidth was 22.1%, which is approximately 5 dB lower than that without an aerogel layer. The results are in excellent agreement with published experimental results to validate the efficacy of the new technique.

scholarly journals A Review on Analytical Modeling for Collapse Mode Capacitive Micromachined Ultrasonic Transducer of the Collapse Voltage and the Static Membrane Deflections

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 714
Author(s):  
Jiujiang Wang ◽  
Xin Liu ◽  
Yuanyu Yu ◽  
Yao Li ◽  
Ching-Hsiang Cheng ◽  
...  
Keyword(s):  
Analytical Modeling ◽  
Ultrasonic Transducer ◽  
Governing Equations ◽  
Von Karman ◽  
Von Kármán Equations ◽  
Collapse Mode ◽  
Capacitive Micromachined Ultrasonic Transducer ◽  
Gap Height ◽  
Von Kármán ◽  
Analytical Expressions

Analytical modeling of capacitive micromachined ultrasonic transducer (CMUT) is one of the commonly used modeling methods and has the advantages of intuitive understanding of the physics of CMUTs and convergent when modeling of collapse mode CMUT. This review article summarizes analytical modeling of the collapse voltage and shows that the collapse voltage of a CMUT correlates with the effective gap height and the electrode area. There are analytical expressions for the collapse voltage. Modeling of the membrane deflections are characterized by governing equations from Timoshenko, von Kármán equations and the 2D plate equation, and solved by various methods such as Galerkin’s method and perturbation method. Analytical expressions from Timoshenko’s equation can be used for small deflections, while analytical expression from von Kármán equations can be used for both small and large deflections.

scholarly journals Design and characteristic analysis of vibration feeding system for coal-gas dust-removal medium

Clean Energy ◽  
2020 ◽  
Author(s):  
Bing Liu ◽  
Lixin He ◽  
Xianglong Zhao ◽  
Qiang Qin ◽  
Yi Guo
Keyword(s):  
Control Unit ◽  
Dust Removal ◽  
Feeding System ◽  
Characteristic Analysis ◽  
Coal Gas ◽  
Measurement Variation ◽  
Gasification Process ◽  
Valve Opening ◽  
Design Requirements ◽  
Design Factors

Abstract A vibration feeder is a piece of equipment for rationing and conveying powder, particle and block materials. In order to test the regeneration performance of de-dusting medium for high-temperature coal gas, a set of de-dusting medium-feeding systems was designed quantitatively. The de-dusting medium-feeding system is used in the gasification process for cleaning coal gas. The system is mainly composed of a hopper unit, control unit and feeding unit. In order to optimize the feeding stability of the coal-gas dust-removal medium vibration feeding system, the setting and scope of the following design factors and operating factors are investigated. Specifically, it includes the influence of gate-valve-opening adjustment of the control unit on the feeding stability of a vibrating feeding system; the influence of the gap size of the dipleg of the control unit on the feeding sensitivity of the vibration system; the influence of the particle size of the de-dusting medium on the operating range of the vibrating feeding system; the influence of the digitization of the working-current indicator of electromagnetic vibrating feeders on measurement variation and the process variation of a vibration feeding system. This vibration feeding system can realize the function of precise and quantitative feeding of the de-dusting medium, which can meet the design requirements of subsequent experimental research.

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