Advanced Materials Research Vol. 1022

Abstract: According to the problem of drag reduction on bionic jet surface, a rectangular jet surface model which is similar to shark branchial shape was built, and numerical simulation was processed by using SST k-ω turbulence model, moreover, influence of jet hole size on the drag reduction performance of jet surface was studied. The results show that: the effect of flow length of rectangular jet hole on the drag reduction is remarkable, with the increase of flow length, fluid friction resistance of the jet surface decreases, the maximum drag reduction rate was 14.38%, and the results of numerical simulation was verified by carrying out experiments. The jet fluid decreases the sweep on the wall of mainstream high speed fluid, which increases the thickness of jet surface boundary layer, thereby reducing the surface friction of the jet hole downstream.

Abstract: In this study, the simulated annealing (SA) algorithm was adopted to optimize the geometry of horizontal plate fin heat sink by the extreme entransy dissipation principle. The alculation of the entransy dissipation rate was presented in detail. Using the entransy dissipation rate as the objective condition, the geometry optimization of the fin heat sink was conducted. To verify the results, the heat source temperature and the entropy generation rate were also calculated in the procedure. It is found that the entrasy dissipation rate, entropy generation and heat source temperature have the similar trend. The extreme entransy dissipation principle and minimization of entropy generation play similar roles in the geometry optimization of plate fin heat sink.

Abstract: In the project of testing platform, characteristics of the measured object are framework. In view of the difficulties of non-contact high-precision measurement of the planar motion objects, an innovative measuring method is proposed which is based on the combined using of high-precision laser distance sensors. This paper presents the structure of the new sensor and its measuring principle, and established a mathematical model of the measurement object and its error model by using differential method. We use the Monte Carlo method to random sample the random sampling of random variables of the error model; finally combining with the instance; we use the Monte Carlo method to get frequency distribution histogram of the measurement error. Through analysis and calculation of this paper, we prepare for theory for the practical application of this new type of sensor.

Abstract: When gear oil pump works, oil chamber is filled with high pressure oil, gear moves between housing and sealing devices and must maintain a certain gap between them, so that leakage is inevitable. In this paper, from structure and working principle of gear pump, the main factors influencing its leakage are spindle end gap, face clearance, radial clearance and the gap of the tooth contact surface. Taking effective measures to control the gear oil pump clearance and improve the working efficiency.

Abstract: With the continuous development of computer networks, security of data is particularly important. AES algorithm is the new data encryption standard after DES algorithm, which has a higher security and faster running speed. Since the promulgation, it has been widely analyzed and multi used around the world. AES algorithm is iterative algorithm,which needs a key generator to generate the encryption and decryption keys for each round.The key generator mainly designs two modules including S box replacement (SubWord) module and Cycle left shift (RotWord) module. After processing results and Rcon array XOR, the key generator may generate an expanded key. The whole design has a simple circuit structure, less resource-intensive, fast running speed advantages, with good prospects for practical applications.

Abstract: A new kind of magnetic elevator is presented in this paper, and the traction force of elevator is provided by the double long-primary short-secondary linear induction motor. The elevator has the advantages of simple structure, less heat, good adaptability. The circuit model of traction motor is established. Magnetic elevator running speed curve is analyzed, and the VVVF control system of linear induction motor for magnetic elevator is designed, and the double long-stator windings are piecewise controlled. Through simulation, the feasibility of the magnetic elevator is verified. The paper laid the solid foundation for the further application.

Abstract: This study aims to investigate the hydro- and aerodynamic characteristics of arrows as understood within the field of archery and to contribute to theoretical knowledge, upon which archery techniques are based. The water tunnel and wind tunnel are used to test different arrows consisting of four famous brands.The results showed that when the angles of attack from -6°to 6°, the arrow remained in the state of attached flow. Arrows that had spiral plastic fletches demonstrated better states of flow than arrows with straight fletches. Within the range of the experimental angles of attack, the coefficients of lift increased, while the coefficients of pitching moment decreased when the angle of attack increased. The arrows showed static stability in the longitudinal direction. Arrow fetches also demonstrated considerable influence on the lift and pitching moment. The rolling of the arrows caused the change of the coefficient of lift. Based on the results, it can be concluded that arrow fetches are the major contributors to the arrows’ flight stability.

Abstract: Firstly, the origin and mathematical mechanism of freeplay nonlinearity ,cubic nonlinearity, hysteresis nonlinearity was analyzed in this paper , and the importance of nonlinear aeroelasticity on structure was pointed out .On the current system of nonlinear aeroelasticity for the method of flutter analysis was summarized. Meanwhile on the mechanism of geometric nonlinearity and analytic methods have been studied, the future direction of the nonlinear aeroelasticity was concluded .

Abstract: Isolation Control System Based on MRF magneto-rheological dampers analyze the structure and mechanical properties for engine isolation, the establishment of magnetorheological damper damping force of the theoretical model to clarify the magnetic current variable damper structural parameters, the motion parameters change its relationship performance impact of electromagnetic fields on the magneto-rheological dampers for numerical calculations. Research magnetorheological engine mounts intelligent control, real-time damping force adjustment, so that the vibration of the engine is transmitted to support the most effective attenuation of the time.

Abstract: Due to the increasing consumption of energy, the improvement of the cooling system efficiency has become very important. We use programmable system-on-chip (PSoC) to fabricate a temperature control system. These chips include a CPU and mixed-signal arrays of configurable integrated analog and digital peripherals. This system controls the cooling fan speed by temperature detecting. This system uses buzzer and liquid crystal display (LCD) to remind the users. The user can start emergency protection means at once. However, we have designed a controller to control fan speed in according with the difference of measured temperature. This research has the function of power saving and elements protection by reducing to turn on and off a cooling fan. With a simple modification, we can turn any control fan by PSoC control. Today, everybody must use electric appliance. We will use PSoC with temperature-controlled method together to control the cooling device.