| Chinese liquor is a popular alcoholic beverage with a variety of geographical origins and roasted aroma styles.The enticing roasted aroma styles are the results of the content of each aroma constituents and the ratio between each aroma constituents.The analysis of the aroma of Chinese liquor is an especially complex problem due to the aroma components' complexity and similarity.Recently,A novel Polymer Quartz Crystal Piezoelectric Sensor electronic nose(e-nose)for classifying Chinese liquor is designed and developed based on the quartz crystal microbalance(QCM)principle.The e-nose contains a gas information collection system and a pattern recognition system.A gas information collection system with an array of eight-channel polymer piezoelectric gas sensor and a variety of pattern recognition systems based on diversified pattern recognition algorithms are employed in the e-nose.Due to the dissimilarity of the polymer material on each sensor,by means of contacting with volatile gas of Chinese liquor,the semi-selective gas sensors would be used as a transducer and transform a progress of physical adsorption into testing frequency signals.Those values of each testing frequency signal decrease at first and then stabilize in the adsorption phase,corresponding to the quartz crystal microbalance(QCM)principle.A variety of the pattern recognition algorithms based on diversified pattern recognition algorithms are utilized to analyze,present,judge and identify the values of testing frequency signals at stable state,which result in classification of Chinese liquors.In order to ensure the reliability and stability of the e-nose for classifying diversified Chinese liquors,much effort had devoted to develop new pattern recognition systems of the e-nose.However,due to the specific testing method and extensive usage situations of the e-nose,the testing frequency signals of the sensors in e-nose are inevitable affected under the influence of environmental physical factors such as magnetic field and flow-induced forces,etc.The testing frequency signals of the sensors under the influence of environmental physical factors are not fully taken into consideration in previous work.In order to evaluating the influence of environmental physical factors on the sensors,the testing frequency signals of the sensors under the influence of magnetic field and flow-induced forces are investigated by using numerical simulation.A list of the main work in this paper is seen as follows:1)The testing frequency shift of the novel Polymer Quartz Crystal Piezoelectric sensor under the influence of stable and unifonn magneto-static field were investigated in the present work.An indirect sequentially coupled finite element analysis which includes an electromagnetic analysis and a piezoelectric prestressed modal analysis with less computational cost and CPU time is implemented in ANSYS/Multiphysics to predict the magnetic forces distribution,piezoelectric stresses and testing frequency shift of the sensor as the stable and uniform magneto-static field applies.2)A 3D Computational Fluid Dynamics(CFD)simulation using the finite volume method is firstly employed to study the influence of the flow-induced forces to the resonance frequency fluctuation of each sensor.A dedicated procedure was developed for modeling the flow of volatile gas from Chinese liquors in a realistic scenario to give reasonably good results with fair accuracy.The flow-induced forces on the sensors are then displayed from the perspective of their temporal and probability density distributions.Finally,to evaluate the influence of the flow-induced forces on each sensor and ensure the serviceability of the e-nose,the standard deviation of resonance frequency value and the standard deviation of resultant forces(Fy)in axis direction(Figure 2-2)are compared.All these results,along with the simulation approach presented in this work,will provide us method references and design references for the design and the optimization process of the e-nose. |
PDF Full Text Request