Dissertations / Theses on the topic 'Ultrasonic atomiser'
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1
Shanmugam, Dinesh Kumar, and dshanmugam@swin edu au. "Development of ice particle production system for ice jet process." Swinburne University of Technology. Industrial Research Institute Swinburne, 2005. http://adt.lib.swin.edu.au./public/adt-VSWT20050805.145343.
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This thesis presents a comprehensive study of the ice particle production process through experimentation and numerical methods using computational fluid dynamics (CFD) that can be used to produce ice particles with controlled temperature and hardness for use in ice jet (IJ) process for industrial applications. The analytical and numerical modeling for the heat exchanger system are developed that could predict the heat, mass and momentum exchange between the cold gas and water droplets. Further, the feasibility study of the deployment of ice particles produced from the ice jet system for possible cleaning and blasting applications are analyzed numerically. Although the use of Abrasive Water Jet (AWJ) technology in cutting, cleaning, machining and surface processing is a very successful industrial process, a considerable amount of secondary particle waste and contamination impingement by abrasive materials has been an important issue in AWJ process. Some alternate cryogenic jet methods involving vanishing abrasive materials, such as plain liquid nitrogen or carbon dioxide have been tried for these applications, but they also suffer from certain drawbacks relating to the quality, safety, process control and materials handling. The use of ice jet process involving minute ice particles has received relatively little attention in industrial applications. Some researches have concentrated on the studies of effects of Ice Jet outlet parameters of the nozzle and focus tube for machining soft and brittle materials. Most of the work in this area is qualitative and researchers have paid a cursory attention to the ice particles temperature and the efficiency of production of these particles. An extensive investigation to gain insight knowledge into the formulation of ice formation process parameters is required in arriving at a deeper understanding of the entire ice jet process for production application. Experimental investigations were focussed on the measurement of ice particle temperature, phase transitions, ice particle diameter, coalescence and hardness test. The change in ice particle diameter from the inlet conditions to the exit point of the heat exchanger wasinvestigated using the experimental results. These observations were extended to numerical analysis of temperature variations of ice particles at different planes inside the custom built heat exchanger. The numerical predictions were carried out with the aid of visualization studies and temperature measurement results from experiments. The numerical models were further analysed to find out the behaviour of ice particles in the transportation stage, the mixing chamber of the nozzle and focus tube. This was done to find out whether the methodology used in this research is feasible and if it can be used in applications such as cleaning, blasting, drilling and perhaps cutting. The results of the empirical studies show that ice particles of desired temperature and hardness could be produced successfully with the current novel design of the heat exchanger. At the optimum parameters, ice particles could be produced below -60�C, with hardness of particles comparable to gypsum (Moh�s hardness of 1.5 to 3). The visualization studies of the process assisted in observation of the phases of ice at various points along the heat exchanger. The results of numerical analysis were found to agree well with the experiments and were supported by the statistical model assessments. Numerical analyses also show the survival of ice particles at the nozzle exit even with high-pressure, high-velocity water/air mixture.
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Meacham, John Marcus. "A Micromachined Ultrasonic Droplet Generator: Design, Fabrication, Visualization, and Modeling." Diss., Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-07072006-103414/.
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Thesis (Ph. D.)--Mechanical Engineering, Georgia Institute of Technology, 2007.Mark Papania, MD, Committee Member ; Mark Allen, Committee Member ; Yves Berthelot, Committee Member ; Ari Glezer, Committee Member ; F. Levent Degertekin, Committee Chair ; Andrei G. Fedorov, Committee Chair.
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Phanphanit, Phattharawdee. "Experimental and computational study of an ultrasonic atomizer." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/experimental-and-computational-study-of-an-ultrasonic-atomizer(f4cb285b-c847-4b15-bd0c-64fa1bd142ce).html.
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A fountain type ultrasonic atomizer was chosen to be a possible device to be used to assist in the alleviation of global warming. Atomization of seawater by an ultrasonic atomizer will enhance more cloud condensation nuclei; as a result, more UV radiation will be reflected back into the space. There are two crucial spray characters: droplet size and the number of droplets. The droplet size needs to be in a certain size range, so that they can stay in the atmosphere. The number of droplets needs to be as high as possible; the more cloud nuclei, the more UV radiation is reflected. The characteristics of sprays are affected by many parameters: liquid properties and the atomizer design. In this study, we characterized two different atomizers: one with a fixed frequency atomizer at 1.72 MHz and one with adjustable frequency and voltage atomizer with a calculated resonant frequency of 2.24 MHz. In addition for the fixed atomizer, different liquid media: tap water (20° C), hot water (46° C), cold water (14° C) and salt waters with different percents salinity (2% - 3.5% by volume), were studied. A Phase Doppler Anemometer was used to measure the characteristics of sprays: droplet velocity, droplet size and number of droplets in a required size range. It was found that the droplet velocity is barely affected by the liquid properties and liquid depth except for the hot water. The relatively high temperature liquid appears to alter the characteristics of the piezo disk; in addition, the inconsistent temperature could vary the characteristics of the spray. The droplet size is strongly dependent on liquid properties and frequency of vibration. The number of droplets is obviously affected by liquid properties and atomizer designs; there is not yet a known correlation between the number of droplets and other parameters. A theoretical study was undertaken in order to compare predicted acoustic properties of acoustic waves with the measured number of droplets generated. The mathematical model was constructed based on applying boundary conditions to a general 2- Dimensional wave equation in cylindrical coordinates. The predicted results satisfy the boundary conditions very well. Since we deal with high frequency acoustic waves, the number of wave modes used in the prediction is significant. It is important to be ensure that all the cut-on wave modes are included otherwise the predicted results will not be very accurate. The more modes that are included, the more computer storage is required; therefore, the number of modes need to be enough to obtain accurate result but not too many to be over the limit of computer storage. The high number of modes used also decreases computer speed, increasing the running time. The mathematical model was used to predict acoustic properties. It was found that the predicted maximum acoustic pressure inside the central small region, where the disk is located, has the best correlation with the number of droplets for all liquid media and all operating conditions. The mathematical model can only predict which operating condition and atomizer design will provide the maximum acoustic pressure. As a result, we can optimize the fountain type ultrasonic atomizer in order to obtain the best result, suiting each application applied. If the geometry is changed, the model is also required to be re-written so that it will predict accurate results.
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Loney, Drew Allan. "Coupled electrical and acoustic modeling of viscous fluid ejectors." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/54247.
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The focus of this dissertation is the development of a fundamental understanding of the acoustics and piezoelectric transducer governing the operation of piezoelectric inkjets and horn-based ultrasonic atomizers when utilizing high viscosity working fluids. This work creates coupled, electro-mechanical analytical models of the acoustic behavior of these devices by extending models from the literature which make minimal simplifications in the handling terms that account for viscous losses. Models are created for each component of the considered fluid ejectors: piezoelectric transducers, acoustic pipes, and acoustic horns. The acoustic pipe models consider the two limited cases when either the acoustic boundary layer or attenuation losses dominate the acoustic field and are adapted to account for changes in cross-sectional area present in acoustic horns. A full electro-mechanical analytical model of the fluid ejectors is formed by coupling the component models using appropriate boundary conditions.
The developed electro-mechanical model is applied to understand the acoustic response of the fluid cavity alone and when combined with the transducer in horn-based ultrasonic atomizers. An understanding of the individual and combined acoustic response of the fluid cavity and piezoelectric transducer allow for an optimal geometry to be selected for the ejection of high viscosity working fluids. The maximum pressure gradient magnitude produced by the atomizer is compared to the pressure gradient threshold required for fluid ejection predicted by a hydrodynamic scaling analysis. The maximum working fluid viscosity of the standard horn-based ultrasonic atomizer and those with dual working fluid combinations, a low viscosity and a high viscosity working fluid to minimize viscous dissipation, is established to be on the order of 100mPas.
The developed electro-mechanical model is also applied to understand the acoustic response of the fluid cavity and annular piezoelectric transducer in squeeze type ejectors with high viscosity working fluids. The maximum pressure gradient generated by the ejector is examined as a function of the principle geometric properties. The maximum pressure gradient magnitude produced by the ejector is again compared to the pressure gradient threshold derived from hydrodynamic scaling. The upper limit on working fluid viscosity is established as 100 mPas.
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Akafuah, Nelson Kudzo. "VISUALIZATION AND CHARACTERIZATION OF ULTRASONIC CAVITATING ATOMIZER AND OTHER AUTOMOTIVE PAINT SPRAYERS USING INFRARED THERMOGRAPHY." UKnowledge, 2009. http://uknowledge.uky.edu/gradschool_diss/792.
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The disintegration of a liquid jet emerging from a nozzle has been under investigation for several decades. A direct consequence of the liquid jet disintegration process is droplet formation. The breakup of a liquid jet into discrete droplets can be brought about by the use of a diverse forcing mechanism. Cavitation has been thought to assist the atomization process. Previous experimental studies, however, have dealt with cavitation as a secondary phenomenon assisting the primary atomization mechanism. In this dissertation, the role of the energy created by the collapse of cavitation bubbles, together with the liquid pressure perturbation is explicitly configured as a principal mechanism for the disintegration of the liquid jet. A prototype of an atomizer that uses this concept as a primary atomization mechanism was developed and experimentally tested using water as working fluid.
The atomizer fabrication process and the experimental characterization results are presented. The parameters tested include liquid injection pressure, ultrasonic horn tip frequency, and the liquid flow rate. The experimental results obtained demonstrate improvement in the atomization of water.
To fully characterize the new atomizer, a novel infrared thermography-based technique for the characterization and visualization of liquid sprays was developed. The technique was tested on the new atomizer and two automotive paint applicators. The technique uses an infrared thermography-based measurement in which a uniformly heated background acts as a thermal radiation source, and an infrared camera as the receiver. The infrared energy emitted by the source in traveling through the spray is attenuated by the presence of the droplets. The infrared intensity is captured by the receiver showing the attenuation in the image as a result of the presence of the spray.
The captured thermal image is used to study detailed macroscopic features of the spray flow field and the evolution of the droplets as they are transferred from the applicator to the target surface. In addition, the thermal image is post-processed using theoretical and empirical equations to extract information from which the liquid volume fraction and number density within the spray are estimated.
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Lessmann, Nils. "Numerical and experimental investigations of the disintegration of polymer melts in an ultrasonic standing wave atomizer." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=974405027.
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Hikaník, Matúš. "Inkubátor s regulací teploty a vlhkosti." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219128.
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This project deals with comparing types and properties of commercial produced incubators for exotic birds. It searches the best solution from these area. In this project are compars individual components and their choice for realization in this project. Then in this project is solution of regulation temperature and humidity in engineered mechanism and discovered parameters of specifically space. Then is developed solution of thermostat and hydrosatat for this prototype. Temperature is changed by Peltier module, who is involved in correct system. Humidity is regulated by resistor humidifier. Complex system is managed by microcontroler. System communicates with PC via USB interface and Ethernet. Solution of this project is maked functional prototyp.
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Chen, Ming-Yong, and 陳明永. "Ultrasonic atomizer." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/86520565466273631519.
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碩士國立雲林科技大學
電機工程系碩士班
100
In this paper the use of vibrator inverse piezoelectric effect, generate ultrasonic frequency range of electrical signals through electronic drive circuit to generate high frequency oscillation principle to promote the piezoelectric oscillator , resulting in their deformation behavior of ceramic materials, squeeze the liquid through the deformation, to current into mechanical vibrations of the ultrasonic wave frequency of vibration of liquid mist particles into very small , that the ultrasonic nebulizer. Production of this paper complete the following five parts of the internal circuit design : (A)the power circuit : 110V 60Hz step-down transformer to generate the required input by the three groups of power , DC24V for the oscillator circuit, fan use , DC 5V micro- controller IC for use. (B) ultrasonic oscillation circuit: the decision of high volatility, piezoelectric oscillator. (C) MCU control circuit: charge (1) control oscillator circuit of the power supply. (2) the strength of spray volume control. (3) low- level detection. (4) PWM three-color LED lights change color mixing. (5) the working state light control. (D) micro- controller IC: to HT4806A-1 as the main control circuit , writing assembly language. (E) the water level detection control circuit: the use of C1815 transistors water level probe to the 1K resistor connected to the MCU''s I / O, the voltage level of the High / Low in the low water level to determine whether state.
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Chen, Hong-Ting, and 陳泓廷. "Preparation of Chitosan Microparticles by Ultrasonic Atomizer." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/ag7xv8.
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碩士國立臺北科技大學
生物科技研究所
97
Chitosan solutions were ultrasonic atomized; then dried by a heated column. The size and morphology of the dried chitosan particles were observed by a scanning electron microscope (SEM). Chitosan particles with narrow distributed diameter from about 0.2 through 3um can be prepared by the ultrasonic atomization under different composition of solution. It was found that the particle size increases with increasing of the concentration of chitosan in acetic solution. Furthermore, chitosan particles loaded with theophylline were prepared by a co-spray drying with the crosslinking agent.
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Lai, Chung-Wei, and 賴春維. "Performance of an Ultrasonic Atomizer with Hartman Resonator." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/39262452625676326229.
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碩士國立成功大學
航空太空工程學系
89
An experimental study is conducted to investigate the atomization performance of an Ultrasonic Atomizer with Hartman resonator. The atomization mechanism of the liquid spray comes the energy of high frequency vibration in the resonator. A typical resonator is called “Hartman generator.” The experiments have a controlling device to control the mass flow rates of the liquid and the atomization gas. The flow field and the droplet size of the spray are measured with the image processing system and Insitec particle sizer. The observation of the flow field shows that the spray cone angles are less than 180 o when the atomizer is operated at appropriate liquid and air pressure. If the liquid pressure is less than the critical liquid pressure, the spray cone angles will be larger than 180 o , a condition called the unstable operation. The unstable operation happens when the reversal air momentum is not balanced by the mechanism of momentum of the incoming air and liquid flow. However, this unstable condition can be improved by increasing the liquid pressure. It is also found the liquid and gas flow rates are mainly determined by the diameters of liquid flow path and the outlet orifice of the atomizers, respectively. The air and liquid flow rates are also controlled by the air and liquid pressures. Results further show that the Sauter mean diameter of this typical spray is better than that from the conventional atomizer. For example, under Pw = 5kg/cm2 and Pa=6 kg/cm2, SMD varies from 10.57 μm to 14.36μm as the resonator size increases from 2.0mm to 3.0mm. Therefore we can see that the resonator plays a very effective role in the atomization. Results also show that the performance of the atomizer is essentially dependent on the air/liquid mass ratio and is approaching a limit when the air/liquid mass ratio is over 1.0. It implies that further atomization of the spray droplets becomes more difficult when they are small length. Hence the increase in atomization gas is less effective to produce smaller droplets. Moreover, the increase of atomization gas is limited by the choking condition of the gas flow at the nozzle outlet. Comparison of various air-assist atomizers indicates that the drop size distribution of internal mixing atomizers in this study, such as CK-5 and H-1 atomizers, is more uniform and the particle sizes are smaller than other atomizers. It is suggested that the atomization mechanism with internal mixing of liquid and gas inside the nozzle is more efficient than that with external mixing mechanism when air speed is less than speed of sound.
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Yang, Fu-Lin, and 楊富麟. "Particle Separation Process Using Ultrasonic Atomizer and Impactor." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/psg248.
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碩士國立臺北科技大學
機電整合研究所
96
This study aims at exploring a laboratory-made micro-fog condensing system and micro-fog impactor which applies the benefits of vibrating foggy effect onto separation of particles. This work also discusses how to process a better separation way in order to get sub-micro or nanoscaled particles. The experiment uses ball-milled ZnO powders as the test sample. This separation mechanism is achieved through the formation of fog created using ultrasonic vibrator. With the aid of fanning and pump, the fog will pass through into impactor, used inertia of particles to separate micro-fog. The ultrasonic atomization is proven to be able to separate micron and nanoscaled particle from aqua. The smallest particle size is 68nm from the experiment and the tendency of separation was the same with little particles inertia. They most influenced with the efficiency of separation in the impactor that changing the entrance of flow velocity and the jet flow diameter by the experiment.
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Chang, Shao-Jui, and 章劭睿. "Power ultrasonic driving circuit model applying to atomizer." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/23469989452139798875.
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碩士國立臺灣大學
工程科學及海洋工程學研究所
98
In recent years, accompanying with the development of the high-speed switch device and microprocessor technology, the range of high power ultrasonic application becomes very broad. The power ultrasonic usually applies to sonar, atomization, cleaning technology, and medical instrument, etc. However, a good designed ultrasonic driving circuits for the power ultrasonic system is very deficient. In General, frequency of high power ultrasonic circuit reaches a maximum of hundreds of thousands hertz, whereas the high frequency circuit can just provide limited power. Long-term steady-going operating is also a problem for power ultrasonic driving circuit on design and in use. Therefore, this paper shows a high power ultrasonic driving circuit model and describes the concepts and manners in detail of each subtle circuit in this circuit model. This circuit model can drive from hundreds of thousands to several millions hertz on the high power condition, and it has high conversion efficiency between mechanical terminals and electrical ones. Even though the application of ultrasonic atomization in engineering is more general and more important, it is rare to have a good ultrasonic atomization system with high efficiency and excellent atomization effect. As result, in this paper, we are going to apply this circuit model to the ultrasonic atomization system. This circuit can drive transducers with resonance frequency between 500KHz to 2MHz. Its output voltage can be adjusted and the maximum rated output power is 30W. Besides, we’re going to observe and discuss the atomization phenomenon of this atomizer, which includes the relationship between the sizes of droplet and driving frequency, the atomization velocity, and the relationship between the droplet size distribution and the driving voltage.
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Li, Chun-Hui, and 李俊輝. "An Ultrasonic Atomizer based on a Langevin Vibrator." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/09437670832244241098.
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碩士國立高雄應用科技大學
機械與精密工程研究所
97
The goal of this study is to propose an ultrasonic atomizer based on the structure of a Langevin vibrator. In this atomizer, the longitudinal vibration is produces through a Langevin vibrator due to the piezoelectric effect. In addition, a conical horn is connected with the vibrator to amplify the longitudinal vibration displacement. The atomization will be produced on the edge of the horn due to the cavitaion phenomenon when liquid flows into the atomizer. In analysis, a commercial finite element software, ANSYS, is used to simulate the characteristics of the atomizer. The vibration modes and displacement distributions of the atomizer are analyzed. And the input impedance curve and the displacement response are also obtained by the harmonic analysis. To verify the analysis, a prototype atomizer was fabricated for the measurements. In the experiments, the impedance curve was measured by the impedance analyzer and the displacement distribution was obtained by a Doppler vibrometer. The error between the measurement and simulation resonance frequency is about 4 to 5%. Finally, the atomization is produced successfully in the experiment.
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Lu, Hsin-Chih, and 盧信智. "Effects of Hollow Pipe Resonator on Hartman Ultrasonic Atomizer." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/6r9r7d.
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碩士國立成功大學
航空太空工程學系碩博士班
90
Abstract Atomization performance of a Hartmann ultrasonic atomizer with hollow pipe resonator and impinging jet resonator is investigated in this research program. The high frequency vibration in the resonator provides energy for atomization of the liquid spray. The particle size of the spray is measured by INSITEC particle analyzer. Observation of the flow field shows that the spray cone angles are less than 180° with the proper resonator height. However, the spray cone angles may be larger than 180° when the resonator height is too low, a condition called the unstable operation. The unstable operation happens when the momentum of the reversal flow in the resonator can not be balanced by the momentum of the incoming air and liquid flow. SMD of the spray is found to be improved by hollow pipe resonator. Further improvement of the spray characteristics is also found in the case of impinging jet resonator. As a typical example, the mean particle size is SMD=27.78μm for CK-5 type ultrasonic atomizer with A-type resonator under h=4mm、Pw=5kg/cm2 and Pa=6kg/cm2 ,while SMD=22.16μm if the hollow pipe resonator is used. If the impinging jet resonator is used, particle size is further reduced to SMD=20.4μm. Comparison of Dv90、Dv10 and size ratio(SR) for the case of hollow pipe resonator and the impinging jet resonator shows the same trend. Dv90=51.03μm and 64.9μm for the impinging jet resonator and hollow pipe resonator, respectively. Dv10=10.73μm and 11.34μm for the impinging jet resonator and hollow pipe resonator, respectively. It turns out that the size ratio reduced to SR=4.75 of the impinging jet resonator, while the size ratio SR=5.72 in the case of the hollow pipe resonator. This implies that the impinging jet resonator has better atomization performance than other cases. Furthermore, the air to liquid mass ratio, ALR, is easily to adjust in the impinging jet case. Result shows that the particle reduces from SMD=20.4μm to 13.65μm as ALR increases from 0.84 to 1.09. The size ratio drops to SR=4.04 as well. Hence eighty percent of the particles are collected within 3 folds of particle size range. It is concluded that the impinging jet can be regarded as the useful mechanism to control the fine particle atomization and it can be used to narrow down the range of the particle size distribution.
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Nguyen, Manh Toan, and 阮孟全. "Mechanical dispersal of silver nanopowder in water using ultrasonic atomizer." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/u82c76.
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碩士國立臺北科技大學
機電整合研究所
96
Nanoparticles have been widely applied into many fields of science, industry, and medicine, etc. However, agglomeration of nanoparticles always exists in every application involving nanoparticles, it strongly reduces the function of nanoparticles and becomes a big challenge. In this research dispersion was focused studied to solve the problem of nanoparticle agglomeration by original mechanical way, which has been considered as extremely difficult. The study proposed two new dispersing methods, where ultrasonic atomizer with the frequency of 1.6 MHz was used as dispersing apparatus. These dispersals were also compared to the well known conventional dispersals such as ultrasonic cavitation (20 kHz) and sonication bath (19 kHz) to evaluate the dispersing function of proposed dispersals. Dynamic light scattering, scanning electron microscope and transmission electron microscope were utilized to study distribution behavior of silver nanoparticles in colloid after dispersal. The experimental results indicated that, two proposed dispersing methods dispersed silver nanoparticles (25 nm in diameter) very homogeneously in water at room temperature with the small average size of dispersed particles (up to 100 nm) and narrow particle size range, a result is much better than that of two conventional dispersals. Moreover, colloids dispersed by two proposed methods were very stable with zeta-potential factor approximated or over 30 mV – stable level of colloid
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LI, CHIH-YING, and 李芝穎. "Preparation of Chitosan/Alginate Particles by Continuous-feed Ultrasonic Atomizer." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/phkg86.
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碩士國立臺北科技大學
化學工程與生物科技系化學工程碩士班
107
Chitosan and alginate particles were prepared by a continuous-feed ultrasonic atomizer coupled with a heating column. The formation of the microparticles was investigated at various compositions of the chitosan, alginate, and crosslinker, and different drying conditions. The size and morphology of the dried particles were observed by a scanning electron microscope (SEM). The particle size could be reduced by decreasing the concentration of the biopolymers in the solution. The analysis revealed that the most types of chitosan or alginate particles prepared were of spherical shape, and the production yield could be higher than 85%. It was found that the particles with different sizes, from approximately 270nm and 630nm, can be prepared successfully at various concentrations. The geometric standard deviations (GSDs) of the dried particle size were almost less than 2, which showed a narrow size distribution. The stability of chitosan or alginate particles in aqueous solution was further observed by a dynamic light scattering (DLS) and a zeta potential analyzers. It was found that the particle size and zeta potential were dependent on the ratio of the crosslinker in the feed and the pH value of solution.
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Huang, Wei-shan, and 黃薇珊. "Application of Phase Locked Loop Circuit for Ultrasonic Atomizer Driving Circuit." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/00949972691563799604.
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碩士國立臺灣大學
工程科學及海洋工程學研究所
100
Resonating frequency and phase of the ultrasonic transducer may change due to variation of temperature and loading and duration of working, etc. Resonating frequency and phase of the ultrasonic transducer varies so that the output power of the ultrasonic transducer might decrease. The purpose of this paper is to design a high power ultrasonic driving circuit module with dynamic frequency tuning and describes the concepts and manners in detail of each subtle circuit in this circuit module. This module can drive from hundreds of thousands to several millions Hz on the high power condition, and it has high electro-mechanical conversion efficiency. This circuit can drive transducers with resonance frequency between 500KHz to 2MHz. We are going to apply this circuit module to the ultrasonic atomization system. It was observed that the higher the driving frequency will cause the phase of ultrasonic transducer drift is more significant. An ultrasonic transducer is precisely set at resonating frequency by phase locked loop circuit. Phase locked loop circuit consists of the feedback of voltage and current, phase detector, low-pass filter and voltage control oscillator. Besides, we are going to observe and discuss the ultrasonic atomization system with phase locked loop circuit. It was observed that the phase of ultrasonic transducer with phase locked loop circuit can be controlled at about zero degree. Otherwise, the phase of ultrasonic transducer without phase locked loop circuit will increase due to temperature rise. It was observed that the transfer efficiency of ultrasonic transducer with phase locked loop circuit can be maintained 95% conversion efficiency. Otherwise, the transfer efficiency of ultrasonic transducer without phase locked loop circuit will decrease due to temperature rise.
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HUANG, CHEN-AN, and 黃鎮安. "Design and Implementation of Multi-Band Ultrasonic Power Control Circuit for Atomizer Frequency System." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/40532595063220990315.
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Hsiao, Chi-Lin, and 蕭祺霖. "Fabrication of array-type dopamine sensors using ultrasonic liquid atomizer for spraying γ-APTES/SiO2 bionanocomposite." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/72399870932952718484.
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碩士國立暨南國際大學
應用材料及光電工程學系
101
The purpose of the thesis is to use the ultrasonic liquid atomizer to spray the sensing membrane of a mixture of 3-aminopropyltriethoxysilane (γ-APTES) and polydimethylsiloxane (PDMS)-treated hydrophobic fumed silica nanoparticles (NPs) onto a polysilicon wire (PSW), investigating the characteristics of electrical interference of the PSW in detectingthe nerve substance of dopamine. The ultrasonic liquid atomizer we used might rapidly spray the γ-APTES+NPs onto the PSW with the advantages of large-area production as well as with good uniformity of the film. We used two methods to do the dopamine detections: 1. Using the 4-carboxyphenylboronic acid (CPBA) to modify the surfaces of γ-APTES- or γ-APTES+NPs-coated PSWs. The CPBA molecules were then used as interfacial layer for bonding dopamine molecules (CPBA modification method). 2. Using the tyrosinase to mix with dopamine solution to produce the hydrogen ions. The γ-APTES- or γ-APTES+NPs-coated PSWs were then used to capture the hydrogen ions (tyrosinase conversion method). We found the optimal conditions for sensitivity through changing the weight ratio of NPs/γ-APTES or the volume ratio of (γ-APTES+NPs)/C2H5OH. It was found that, for both the CPBA modification and tyrosinase conversion methods, the optimal conditions for two methods were the same, that is, the weight ratio of the NPs to γ-APTES was 1% and the volume ratio of the γ-APTES+NPs to C2H5OH was 0.2%. For the optimal conditions, the dopamine sensor exhibited the best performance of sensitivity and linear detection region in dopamine detections. For the CPBA modification method, the lowest detection limit is 10-6 M, and the linear region is in the range of 10-3 M ~ 10-6 M. For the tyrosinase conversion method, the lowest detection limit is 10-11 M, and the linear region is in the range of 10-3 M ~ 10-11 M. We found that the tyrosinase conversion method is better than the CPBA surface modification method. Neverthless, both methods can be used for dopamine sensing application. We successfully fabricated the low-cost dopamine biosensor array by batch production using the ultrasonic atomizing for spraying the large–area γ-APTES +NPs membrane with good uniformity.
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Tsai, Kai-Hsun, and 蔡凱勛. "Fabrication of array-type glucose sensors using ultrasonic liquid atomizer for sprying γ-APTES/SiO2 bionanocomposite." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/17244784853860831648.
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碩士國立暨南國際大學
應用材料及光電工程學系
101
The aim of this thesis focuses on the film deposition of γ-APTES mixed with PDMS-treated silica nanoparticles (NPs) by ultrasonic liquid atomizer for sensor applications, investigating the effects on glucose sensing property of the film in different NPs/γ-APTES weight ratio, different γ-APTES/C2H5OH concentration ratio, and ultraviolet (UV) light exposure. The reason we deposit the γ-APTES+NPs nanocomposite thin film on poly-silicon wire (PSW) by an ultrasonic liquid atomizer is that we might fabricate the glucose sensors array by batch production. We first characterize the surface morphology and measure the vertical leakage current by using atomic force microscopy (AFM). Then, the sensitivity of glucose sensors array is analyzed. It is found that the vertical leakage current of the sensing film increases with NPs/γ-APTES weight ratio in the range of 0% to 1%, and increases with the concentration ratio of (γ-APTES+NPs)/C2H5OH. In comparing the distribution of the values of vertical leakage current, we prove that a uniform γ-APTES+NPs nanocomposite thin film is successfully deposited by using ultrasonic liquid atomizer method. We find that the permance of the batch fabricated glucose sensor array is nearly as good as our previous result which was fabricated by AFM tip coating method. According to our experimental results, the optimal conditions for the glucose detection are 1% weight ratio for NPs/γ-APTES, 1% concentration ratio for (γ-APTES+NPs)/C2H5OH and 120 s for UV exposure. The lowest detection limit is less than 10-9 M, and the linear detection region is from 10-2 M to 10-7 M. Comparing with our previous results, the lowest detection limit and the linear region are nearly the same as the tip-coating method. The sensitivity is about 80% of that tip-coating result. The ultrasonic liquid atomizer spray method can effectively reduce the costs and simplify the process to achieve the goal of a rapid production for large area of sensing membrane.
21
HUANG, REN-HONG, and 黃任宏. "The Analysis of Combustion Engines Emission by Using Water Vapor Injection with Water Temperature Control and Ultrasonic Atomizer." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/ryh869.
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碩士國立高雄應用科技大學
工業工程與管理系碩士在職專班
106
At present, most Taiwanese people use motor vehicles to solve the traffic inconvenience problem, so the number of motor vehicles is still high. In recent years, due to the rising awareness of environmental protection, the issue of exhaust emission from motor vehicles has been paid attention to. However, in the case that the number of motor vehicles cannot be effectively reduced, in order to improve the exhaust emission, an additional channel has been added to the intake manifold of the engine. The channel is to absorb water vapor generated by the ultrasonic nebulizer in the combustion improvement device through the negative pressure suction generated by the engine when the intake valve is opened, so that the air and water vapor are fully mixed and then enter the engine for combustion to realize the influence of water vapor on the exhaust emission from the engine. In this experiment, thermoelectric module were used to change the temperature of the water in the device. Water vapor were produced by the water at three different temperatures, namely, cold, normal and hot, respectively, to enter the combustion. It is found that cold water can lower the air temperature and increase the density, which has better combustion effect compared with the other two temperatures. Hot water will increase NOx when the air-fuel ratio is rich in oil and gas. It is because the air temperature increases and increases the fuel atomization efficiency, and it also provides more combustion-supporting materials and combustibles, resulting in higher engine temperature. The normal temperature water is less able to improve the combustion efficiency, but it can prevent the combustion chamber temperature from being too high and reduce more NOx emissions.
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Lessmann, Nils [Verfasser]. "Numerical and experimental investigations of the disintegration of polymer melts in an ultrasonic standing wave atomizer / von Nils Lessmann." 2004. http://d-nb.info/974405027/34.
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Chou, Chen-Ying, and 周禎英. "Properties and applications of ZnO thin films prepared using a homemade atmospheric-pressure plasma jet assisted with an ultrasonic atomizer." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/2gg699.
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