Applied Mechanics and Materials Vol. 472

Abstract: The direct steam generation (DSG) with parabolic collector is an attractive option regarding the economic improvement of parabolic technology for solar thermal electricity generation system. On the basis of theory analysis of flow and heat transfer mechanism in the DSG system, this paper presents the numerical simulation results of one 650 meters loop under different direct normal irradiation values, performance parameters such as water temperature, heat transfer coefficient and dryness of the fluid in the absorber pipe are obtained in the simulation results. This paper shows that fluids parameters are susceptible to the solar direct normal values , high heat transfer efficiency and sensitive control system are the key to ensure DSG systems stable operation.

Abstract: On the way to further exploit offshore wind energy, conventional fixed-bottom technology has been limited by the water depth. After the worlds first full scale floating wind turbine being installed in the North Sea in 2009, the floating support structure for offshore wind turbines is most likely becoming not only a technically feasible but also an economically viable solution, especially for regions of water depth over 50 meters. However, less attentions have been paid on floating support strucure, which is a very important part. Derived from commercialized offshore oil and gas platform of cell spar, a conceptual design of a cell-spar-buoy support structure for NREL 5 MW offshore wind turbine is proposed. In this system, structural type of cells is absorbed for cost reduction while damping configurations are used to optimize the stability of wind turbine. For further hydrodynamic performance estimations, numerical simulations have been performed to compute the response amplitude operators (RAOs) and the wave response motions, which are the key factors of the preliminary design. Meanwhile, the motion performance of the platform with mooring system in operating conditions and mooring line tensions under the 50 years return period storm survival condition in the South China Sea was calculated in time domain. The results showing excellent motion performance of cell-spar-buoy.

Abstract: This paper aims to present the project a small wind turbine for generating electricity in urban area. The wind turbine of this project is the horizontal axis of 3 and the rotor blades upwind of the tower. Its rated power is 500W applied to be incorporated into stand-alone systems and connected to power grid in urban areas. The guidance system was developed by the design of a passive system. Based on the concept of a permanent magnet synchronous machine designed to power the system. was adopted the value of 6 m/s and rated speed of the wind system and observed the distribution of wind speed, the normal model of turbulence and wind profile normal. Based on such information from the wind rotor airfoil was chosen using the software of the Sandia National Laboratory, is the radius of 1.88 m. A permanent magnet synchronous generator 4-pole generator was chosen by analyzing the output voltage, the induced current in the pair and the internal power supply. In the first part of the wind turbine power curve, was defined a control law that varies the connected load. In the second part of the curve a passive system takes care of misalign the rotor to avoid overcoming the current rating. This is because to increase the power output is necessary to increase the radius of the rotor which, in turn, implies a decrease in its speed. The structural model was developed for the analysis of the blade of their aerodynamic loads, inertia and gravity.

Abstract: Engine is carried the test on the thermal balance test and the drag test in the vehicle working condition to analysis the distribution of energy from combustion. The heat of coolant that combustion flow into the cooling system in different temperature is not the same. The results show that the engine heat comes into the cooling system ranging minimum at 3000-4000r/min, the effective power output accounts for the total energy up to 25% at full load reaching the maximum. Based on the data, it is established the control system of engine cooling module that can be controlled by the engine speed, torque and power, when the ECU reads the signal to forecast the combustion energy flow to the cooling system in the target vehicle working conditions establish the cooling module heat release control system.

Abstract: For improving the control precision of electro-hydraulic synchronization position servo system, the nonlinear and non-Gaussian time sequence prediction model is constructed and nonlinear and non-Gaussian time sequence prediction procedure was built by RBF(Radial Basis Function) neural network and HMM(Hidden Markov Model ). A cascading failure prediction method in electro-hydraulic synchronization position servo system based on nonlinear and non-Gaussian time sequence prediction model was established to investigate the emergent behaviors of cascading failures and to further study the prediction and defense of cascading failures. Finally, this method was demonstrated and validated by a sample. It has shown the proposed method can improve the benefit of control precision in electro-hydraulic synchronization position servo system, and provide a support for adapting to solving dynamic error problem.

Abstract: Ref. [ based on the analysis of internal tooth plate in the process of locating method, on the basis of the author thinks that the positioning adjustment of internal tooth plate Angle is not easy to measure in actual processing, the positioning adjustment Angle is not easy to guarantee the positioning, a direct impact on the accuracy of phase difference between tooth plate. If the difference accuracy of inner teeth cannot guarantee, cause vibration and noise, impact of three-ring gear reducer will intensify, temperature increase, reduce the service life, even can't assembly. Through the analysis of the principle of three-ring gear reducer, the paper puts forward the inner tooth plate treatment positioning adjustment Angle is 120°, measurement is simple and convenient location, is advantageous to the guarantee of phase difference accuracy of inner teeth. Using UG NX7.0 platform, with a new positioning method to establish model of inner rack, and then using UG stretch command on the establishment of good internal tooth plate model of cutting out the tooth shape, and motion simulation. The results show that the new Angle of inner gear plate positioning adjustment feasible, and fast and convenient, has important significance to the development of three-ring gear reducer.

Abstract: With the development of smart grid, the intelligent low voltage apparatus also gradually accepted by people, as well as the higher request about the intelligent detection system for operating frequency of approach switch. The present conditions, a new key technology and the developmental prospects of the intelligent detection system for operating frequency of approach switch are discussed in this article.

Abstract: In this paper, the problem of vehicle yaw control using differential braking is investigated. The proposed control structure employs the wheel slip controller to apply differential braking to generate the yaw moment calculated by the yaw controller. A fuzzy logic based target slip allocation method is also designed. Due to system uncertainties and wide range operation conditions, two different yaw controller which are based on sliding-mode control and PID control are designed, and their performances are compared by hardware in loop simulation. The obtained results show the effectiveness of the proposed control structure with both yaw controllers, but the sliding mode based yaw controller can be more robust.

Abstract: This paper describes a control strategy of drive modes switch for an independent eight in-wheel motor drive vehicle. There are three drive modes, and they are eight-wheel drive with ASR mode, eight-wheel drive mode and four-wheel drive mode. The control strategy is designed to improve the integrated performance of the vehicle, such as safety, dynamic performance and economic performance, but the previous research can only improve one of them. When the road adhesion coefficient is very small, the vehicle will drive in eight-wheel drive with ASR mode to ensure the vehicles safety, when the driver torque demand is very big, the vehicle will drive in eight-wheel mode to get better dynamic performance and when the driver torque demand is very small, the vehicle drive in four-wheel mode to get better economic performance. The vehicle switches among the three modes according to the driving condition. Simulations of the new control strategy were carried out on two different driving conditions. The results showed that an improvement in safety or economic performance was achieved with the control strategy.

Abstract: The wind tunnel test dating for the cooling module in the vehicle conditions shows that the actual fan rotation is evidently different from the fan in bench test rotation. There is an intake high pressure zone. It is easy to conduct airflow into the cabin, and under the cabin, there is a negative pressure zone. It is easy to conduct airflow outside the cabin. Both of the different pressure zones affect the fan rotation. Air path of the cabin is divided into three different areas. Base on the parameters of CP BIR and-CP, the aerodynamic characteristics of the cabin build the cooling module under the vehicle working conditions. The model can predict the states of the fan working, when the target vehicle speed conditions are met, and it has important application value for the design of intelligent cooling module control system as well.