Advanced Materials Research Vols. 466-467

Abstract: To achieve transient flow characteristics at exit of nozzle orifice on gasoline direct injection engine, two phase Euler-Euler schemes was used to simulate the internal flow of the swirl nozzle. Different flow characteristics were calculated in the simulation. Different kinds of nozzle configuration were studied. Cavitaion and swirl flow occured in the nozzles. Injection hole configuration matters more than area variation of swirl tangential slot to discharge coefficient of the studied nozzle. Discharge coefficient changes a little along the injection hole length. The area of the swirl tangrntial slot plays an important throttling action in nozzle internal flow. Smaller area of swirl tangential slot generates larger degree cavitation but smaller mean injection velocity. Turbulence kinetic energy changes with the time of cavitation and swirl field occurring and the nozzle configuration. Before the appearance of cavitation, smaller inclination angle of orifice can generate more turbulence kinetic energy. After that moment, turbulence kinetic energy varies with different configuration. Along injection hole length, turbulence kinetic energy obviously varies. These flow characteristics affect primary atomization and will be as input for next spray simulation. They are also applied to design reference for injection nozzle.

Abstract: Surface-to-air missile equipment is an advanced aerial defense weapon equipment of middle-high altitude intermediate range in our army, and this weapon equipment is also shouldering the significant task of antiaircraft defense of our country. Therefore, researching on its Fault Intelligent Diagnosis System has an important practical significance and military value on improving the weapon equipment’s renewing of fault and keeping the army’s battle effectiveness.

Abstract: In this paper, a controller is designed based on improved fuzzy PID to solve the problem that the dc motor performance of speed and dynamic is poor when using the conventional PID controller for the lack of adaptive capacity of the controller parameters. The improved fuzzy control algorithm is used for the tuning of PID controller to get good speed performances, which automatically adjust the parameter of PID controller according to the motor speed. The simulation results show that the improved fuzzy PID control with the advantages of fast response, small overshoot and strong anti-interference capability can effectively improve the dynamic characteristics and steady state accuracy.

Abstract: Equipment monitoring and fault diagnosis is a focus in the researching the industry. With the improvement of the safety, stability and reliability about the equipment; and the application of computer network technology, signal analysis and processing technology, these make more and more attention that online monitoring and fault diagnosis mode are based on network. In the context, combined with “The Online Monitoring and Fault Diagnosis System of Gas Fan in Converter OG” system in some steelmaking plant, the gas fan is taken as research object, the monitoring vibration and fault diagnosis system about the gas fan will be made and developed in this paper. The practice shows that the scheme of the developed system is feasible and practical. Convenient operation, inspection rapidly, diagnosis accuracy highly, which have satisfied the production need and remarkable economic benefit for the corporation.

Abstract: The stress with different shapes under the same load is analysed and the thickness of the leaflets 0.2mm and 0.4mm is compared by us. We creat the spherical, paraboloidal and ellipsoidal curved surfaces in accordance with geometrical features. The experimental results of the finite element analysis show that stress distribution of the same bioprosthetic heart valve leaflets with different thickness is different. The maximal primary stress with the thickness of 0.4mm is lower than the others.With the same thickness,the stress of the ellipsoidal valve leaflets is lower. This work is very helpful to manufacture reasonable shaped valvular leaflets and to prolong the lifetime of the bioprosthetic heart valve.

Abstract: Based on techniques from the state observer design and the pole placement technique, we present a systematic design procedure to synchronize a modified coupled dynamos system by a scaling factor ( projective synchronization ). Compared with the method proposed by Wen and Xu, this method eliminates the nonlinear item from the output of the drive system. Furthermore, the scaling factor can be adjusted arbitrarily in due course of control without degrading the controllability. Finally, feasibility of the technique is illustrated for the unified chaotic system.

Abstract: Based on the physical numerical modeling of the hydraulic poppet valve, the inside flow field was simulated by numerical method of the dynamic mesh technology of Fluent. The analysis results indicate that the intake rate and flux are reduced by minishing the poppet. And the eddy section’ s length of the intake and the concave corner of the valve core is gradually minished and disappeared at last.

Abstract: The prevenient mechanical research on U type steel support focuses on two dimensional analysis in the installing plan. Interested in the buckling failure of U type steel support’s pinnas in one coal mine of Huainan Group, the authors build three dimensional models to stimulating 25U and 29U support. The appealing simulation results verify ANSYS’s 3-D computational capabilities about complicated section support. The main objective of their investigation has been to obtain some knowledge of the mechanism, stress distribution, and load magnitude in the support’s deforming. Further, the deviating longitudinal load play an accelerating deformation role on its distorting, which should be paied more attention to cross-section optimization, design of support parameters, and installing way of steel lacing.

Abstract: Because of its high performance, brushless DC motors are widely used in vehicles. But the brushless DC motor speed system itself is easily influenced by the parameter variation, the cogging torque and the load disturbance. And some complex algorithms to overcome the deficiency are difficult to implement on a single DSP chip. To solve the problem, the paper represents a nonlinear PID controller based on DSP and FPGA. A functional design of FPGA in a brushless DC motor system based on FPGA and DSP was completed by using modular design method. All the function modules are programmed by Very-High-Speed Integrated Circuit Hardware Description Language (VHDL). The simulation and experiment results indicate that nonlinear PID can improve the performances of the servo system in rapidity, control accuracy, adaptability and robustness.

Abstract: Frame acts as the structural backbone of a truck, which supports the components and payload placed upon it. When the truck travels along the road, the frame is subjected to vibration induced by road roughness and excitation by vibrating components such as power-train, transmission shaft and more that mounted on it. Though many researchers have made great progress in the static and dynamic analysis of truck frame, most research was based on the assumption that all the design parameters of truck frame were deterministic. However, design variables for truck frame are always uncertain in the actual realistic engineering cases due to tolerances in manufacturing and assembly processes. In this paper, fuzzy algorithm is introduced to analysis the response of the frame with uncertain parameters. By using fuzzy set theory, uncertain input parameters such as the elastic modulus, Poisson ratio are described mathematically as fuzzy variables or fuzzy random variables and integrated into mode analysis. The simulations are carried out to analysis the system performance under fuzzy uncertain parameters. Results are presented showing the effectiveness of the method for modeling systems with uncertain parameters.