Applied Mechanics and Materials Vols. 220-223

Abstract: As the development of the Microprocessor technology, Power electronic technology, Motor manufacturing technology and modern control theory, Variable frequency system is used more and more widely.This paper introduces a design of motor variable frequency control system．AC-DC-AC-circuit is used in its main circuit, and U/F control strategy is used in its controlling method．Based on the system parameters，the calculation and selection of the component parameters are carried out．Finally，the intelligent power module(IPM)is used as a power inverter circuit switching devices and TI DSP(TMS320LF2407A) is as a core control to improve the precision and stability．The experimental result indicates that the driving system has the stable performance, high anti-interference and high value.

Abstract: The brushless DC motor control system often adopts the classic PID control, the advantages of which are as follows: simple to control, easy to adjust the parameter and a certain degree of control precision. But it relies on accurate mathematical model. The permanent magnet brushless DC motor control system is a multi-variable and nonlinear. As to the deficiencies of the classic PID control method, this thesis proposes a method called artificial neural network PID adaptive control method, which is based on algebraic algorithm and overcomes the shortcomings such as the slow convergence of BP algorithm, easy to trap in local minimum, and etc.

Abstract: In order to study heat transfer process in APU compartment of passenger plane and to perform structure thermal analysis, temperature field of APU compartment has been calculated by numerical computation. The computation model of flow and heat transfer process in APU compartment are setup by commercial CFD software Fluent, Realizable k-ε turbulent model and S2S thermal radiation model are used, and the flow field, temperature and heat flow information are acquired. Radiation heat transfer is the major heat transfer process in APU compartment; APU fireproofing cover and heat insulation hood of exhaust pipe function work as radiation heat shielding screens; and cooling air in the APU fireproofing cover plays an important part in decreasing the temperature of the fireproofing cover; the injection cooling air in the exhaust pipe reduced the wall temperature effectively. The results provide reference to optimization design.

Abstract: In this paper, as the research object a manual piston pump is designed lightweight, by using optimization theory and the finite element analysis method. The manual piston pump body, the piston and the end cover are designed proper structures include diameter, height, ayout, etc. The optimized calculation and research analysis provide credible theory and experience for engineering application.

Abstract: In order to improve the degree of automation in plastic pipe production and save labor cost, this paper proposes a design scheme about the electric control system design of straight pipe automatic conveyor line. The Programmable Logic Controller (PLC) is the core control component in this system. This system can control the start and stop of production lines by applying communication between computer and PLC, change the number of each bundle of pipes, and monitor online the operation conditions of automatic transmission lines. Finally, actual operation of the system shows that it runs steadily, operates simply, and is highly automatic with low labor cost.

Abstract: The steam-water separator is the most important pressure part of the Ultra Supercritical Boiler（USB）. The steam-water separator’s service life is related to the monitoring of the security issue of the UCB. The steam-water separator typical structures of the domestic 1000 MW ultra-supercritical boiler are compared. The difficult problems in the separator’s manufacturing process are analyzed. The separator coupling stress field is simulated through the finite element method. The results show that the maximal stress locates on the long shaft position of the elliptic hole interfingering lines where has the serious stress concentration. That point is the key spot of the strength analysis and life monitoring during the boiler operation process.

Abstract: An experimental study is made on the emission of a single-cylinder direct injection diesel engine with different proportions of GDE and diesel. The study shows the mechanism when GDE is added to diesel to reduce diesel emission. And an analysis of pollutant emission is made on the regularities of variation with engine load changes. The results show that the addition of diesel oil in the volume fraction of 10% to 20% of GDE can significantly increase the thermal efficiency, shorten the duration of diesel combustion, substantially decrease carbon smoke and CO in emission under the high-load conditions and slightly lessen the NOx emission, but HC emission still remain basically unchanged.

Abstract: In order to better simulate the flowing condition of wet gas, Tianjin University has designed and built up a wet gas flow experimental facility with adjustable and intermediate pressure in the flow laboratory. The designed pressure of the facility which used standard meter method and dual closed-loop design is 4MPa. The experiment medium is air and water, and the highest operation pressure is 1.6MPa. The gas flow rate range is 3~1000m³/h, and the liquid flow rate range is 0.05~8 m³/h. This article includes the structure introduction of the facility and the calculation of pressure loss of the system, etc. By the uncertainty assessment for the discussed facility, the conclusion is stated that the facility’s gas measurement uncertainty is 1% and the facility’s liquid measurement uncertainty is 0.35%.

Abstract: According to the problem of large overshoot in the variable pump constant pressure output, the fuzzy controller and PID controller were combined. The dynamic response of system output pressure was obtained by combining simulation with a fuzzy adaptive PID controller designed in Matlab/Simulink and mechanical hydraulic model established in AMESim. The simulation results show that fuzzy PID control can achieve the goal of system response without overshoot, and response speed is improved further. The anti-interference ability is also stronger.

Abstract: Plane four-bar linkage is widely used in mechanical products; it is a decisive factor to define the characteristics and output of crusher as the key mechanism for the model crusher. At first, expound and classify the critical parameter in theory; then ADAMS is used in parameterized modeling of plane four-bar linkage, according to the simulation optimization data of critical parameter in ADAMS, the relations among the critical parameter and influence on crusher performance are demonstrated after numerical analysis. Finally, the optimal critical values are optimized, which are applied into the design of a crusher.