Advanced Materials Research Vols. 443-444

Abstract: The micro-machined gyroscope was manufactured through CETC13 SOG process and packaged with ceramic DIP-24 at vacuum pressure. In this paper, the bipolar decoupling micro-machined models were analyzed, the drive and test mode frequency at atmospheric pressure were tested, the scale factor and the output noise were mensurated. The results showed that the high linearity micro-gyroscope had achieved high linearity and good dynamic character at atmospheric pressure.

Abstract: . In this paper, blends of butanol-biodiesel-diesel were tested inside a constant volume chamber to investigate liquid spray and combustion of the fuels. With high-speed camera and synchronized copper vapor laser, spray penetration during injection is recorded since it has a higher light reflectivity. Various ambient temperatures and fuel composition were investigated. There is a sudden drop in spray penetration at 800 K and 900 K, but not at 1000 K and 1200 K. When the spray penetration of the butanol-biodiesel-diesel blends is compared to that of the biodiesel-diesel blends, under non-combusting environment, a sudden drop in spray penetration length is also observed at 1100 K. High speed imaging shows that, for the non-combusting case, at 1100 K, the tip of the spray jet erupts into a plume sometime after injection for the butanol-biodiesel-diesel blend. The same is not seen with the biodiesel-diesel blend, neither at lower ambient temperature of 900 K. It is concluded that micro-explosion can occurs under particular conditions for the butanol-biodiesel-diesel blend, and the results is consistent with previous study in the literature.

Abstract: Different blend ratio of ternary component fuel was tested inside a constant volume chamber to investigate fuel injection and combustion under similar real engine working conditions. Because liquid spray light scattering is the different reflective rate from the liquid droplets and its surrounding background, butanol-biodiesel-diesel liquid jet penetration length can be highlighted in the images taken by high speed camera. Various ambient temperatures from 800K to 1200K and fuel composition were investigated. Measured results showed that sudden but repeatable drop of liquid jet penetration length at constant ambient temperature conditions of 800K and 900K. With ambient temperature increasing, this phenomenon became weak and disappeared. So more works focus on non-combusting experiments in order to delete combustion reflect. With butanol and biodiesel content increasing, micro explosion becomes prone excited and more violent because of the enlarged differences in volatilities and boiling point among the components. It is concluded that micro explosion which will distinctly enhances premixed combustion process and heat release rate but it present under certain initial ambient temperature conditions only and the light fuel content shouldn’t be lower than 10%.

Abstract: .In order to manufacture high quality intake port with bigger discharge coefficient and appropriate swirl ratio for diesel engine performance improvement, intake port tests and CFD simulation method were combined together to optimize its structure. The three-dimensional CAD model of intake port was built and was putted into AVL–FIRE platform to do CFD simulation with appropriate turbulence model and calculation method. The detailed air flow information was obtained by CFD simulation. After analyzing, two optimization programs were discussed. This research shows that CFD simulation is a powerful method to design diesel engine intake port; air flow condition is complex in the intake port; intake port structure optimization can increase the discharge coefficient and improve the air flow condition.

Abstract: .In order to improve the performance of automobile tube-core-fin radiator, the thermo-test and mathematics model method were combined together to study heat transfer and air resistance. The mathematics model was built including heat transfer and air resistance coefficient criterion equations in the certain Reynolds number range. The maximum relative error between results calculated from mathematics model and test values is less than 6.61%. The number of tube rows of the radiator can affect heat transfer and air resistance coefficient through analyzing results.

Abstract: Due to the mutual radiation impedance may influence acoustics performance of a broadband dense plane array seriously, the expression of mutual radiation impedance among the transducers is developed according to the definition of mutual radiation impedance based on BEM（Boundary Element Method）. BEM model is established for acoustic radiation of a broadband dense plane array with nine elements. Sound pressure distribution of the nine-element array is solved using SYSNOISE software. And mutual radiation impedances are calculated on the condition of knowing surface normal velocity. Acoustic performance of the nine-element array is analysed through mutual radiation impedance. The influence of mutual impedance on acoustics performance for nine-element array is verified by comparing with measured curve of transducer conductance. The results show that it is successful to calculate mutual impedance of the array and predict acoustics performance using BEM.

Abstract: A turbocharging lean burn LPG engine combustion model is set up by using three-dimensional simulation software. And the numerical simulation of the engine working process is done. Based on the model validation, the effect of the engine working process is calculated and analyzed by comparing with different ignition models (single spark ignition and dual spark ignition) and the simulation results are validated by experiments. The results show that: dual spark ignition (DSI) model as compared to single spark ignition (SSI) model can reduce flame propagation distance, form the stronger swirl rapidly, accelerate the flame propagation speed, reduce knock phenomena, reduce the emission temperature and improve the engine efficiency. Therefore, the engine has better power performance and fuel economy.

Abstract: .To study the dual-spark ignition methods of combustion of LPG, numerical simulation is conducted on the lean burn LPG turbocharged engine by three-dimensional simulation software.Based on the model validation test of dual-spark ignition model engine, the effect of synchronization ignition and asynchronous ignition are discussed.The results obtained show that asynchronous dual spark ignition model can be helpful to reduce flame propagation distance, form the stronger swirl rapidly,accelerate the flame propagation speed significantly,improve the rapid lean-burning process of LPG engine. Meanwhile, the results will also offer theoretical guidance for combustion optimization.

Abstract: In this paper，adopting wavelet neural network，fault forecast of characteristic parameters of Wind turbine are realized by forecasting time series of key characteristic parameters of Wind turbine that include vibration intensity. With more degree of freedom in relation to the general neural network, wavelet neural network is in possession of more vivid and more valid ability in function approximation. With the good partial characteristic and distinguish rate learning wavelet neural network realizes the signal with good matching, and then wavelet neural network had stronger self-adaptation ability, more sooner convergence rate and higher forecast accuracy. Emulation and experiment result show that the forecast accuracy of the wavelet neural network meets demand and is of far reaching importance to guarantee the steam turbine circulate efficiently safety .

Abstract: The value of brake friction coefficient have to do with temperature rises、speed、press and the influence of temperature rise is most large.Because high speed mine hoist come into being high temperature in apply the brake，it affect friction coefficient and capability of apply the brake system. therefore，unfold study brake temperature rise and friction coefficient forecast is very importance meaning.Because ANN can reflect non-line relation of input and output，this paper puts forward description mapping relation and effect to apply the brake safety of with temperature rises、speed、press and the influence.