Applied Mechanics and Materials Vols. 448-453

Abstract: This paper analyzes the load characteristics of electric vehicle under different charging modes including disordered charging, peak shifting charging and continuous charging. Taking a typical distribution network in Beijing as the research object, the calculation of steady state operation is carried out under the three kinds of charging modes after the integration of electric vehicles at different scales. The voltage deviation and load rate are analyzed to reveal the impact of charging modes on the capability in absorbing electric vehicles in Beijing grid.

Abstract: Because of the energy crisis and environment deterioration, there is a general consensus about the development of new energy vehicle especially electric vehicle in the world. The development of electric vehicles has brought new challenges to the distribution network. The charging strategy, the location planning of electric vehicle charging stations and sizing, the coordination planning between electric vehicle and the distribution grid depends on the future development scale electric vehicles and charging load forecasting. Because there is a certain distance from commercial operation in china, the prediction theory and method of the electric vehicle development scale and charging load are not mature. By using the method of artificial neural network to establish the development scale and charging load forecasting model of electric vehicle. The model is proved its correctness through an example of the electric vehicle scale and charging load forecasting of Kunming, a big city in West China. The paper provides a new way for future development scale and charging load forecasting to electric vehicle of China.

Abstract: This paper introduces the optimal electrical system design for a solar car, which complies with the regulations of World Solar Challenge 2013. The optimal design principles of high efficiency, light weight and high reliability were proposed. The solar energy collection system, energy storage system, drive system and electronic control system were all designed under the guidance of the principles. The structure and working principle of the solar car electrical system are also introduced. The experimental results show that the design goals have been achieved, and the performance of the system has also been verified.

Abstract: The influence of surface polaritons on spectral energy flux at different temperatures or distances to the surface of a plate was analyzed. The relations of the net heat flux between two parallel plates with the material type were also discussed. The results demonstrate that the effect of surface polaritons is dominated in the spectral energy flux at 300 K when the distance is decreased to 100 nm. In addition, the intensity of surface polaritons increases with the temperature. The net heat flux between two parallel plates has a nearly linear relation with the temperature and is closely related to the material type. It reaches up to 2.792×10⁷ W/m² between two SiC plates, approximately 3~6 orders of magnitude larger than that between two different materials. However, the net heat flux between SiC and Al is merely 2329.7 W/m², even smaller than the result calculated by the classical stefan-boltzman law between two blackbodies.

Abstract: The new unit putting into production is the supercritical boiler with a level of or above 600 MW, and most of them take the corner tangential combustion technology. The Long-term operation practice shows that there is gas temperature deviation on all the horizontal flues of boilers, which usually leads to the overheating tube burst of the high-temperature superheater and reheater, thus threats the safe and economic operation of power station. Towards the gas temperature deviation phenomenon that exists commonly in tangentially fired boiler, this paper went on the pertinent cold-state aerodynamic field test on the tangentially fired boilers in one new power plant and studied the airflow velocity at the furnace outlet in eight vertical levels by changing the SOFA horizontally rotating angle. The experiment showed that changing the baffles opening and horizontally rotating angle of SOFA air door could adjust airflow quite well and make it uniform, furthermore, the airflow can reach a basic balance at the biggest anti-tangential angle. This paper has some reference value towards improving the gas temperature deviation problem of tangentially fired boilers.

Abstract: Meshless method calculation accuracy is influenced by many factors, in which influence domain and node distribution are the most important. Due to the restrictions of the meshless methods themselves, their respective influence factors are different. In the paper, the advantages and disadvantages of the collocation method, the meshless method based on the local weak formulation and collocation (MWS), the meshless radial basis interpolation method based on global weak formulation (RPIM) and the weighted least squares meshless method (MWLS) are discussed by comparing the average error of nodes value in different influence domain radius. The results show that the accuracy of the MVS method is higher, but not stable; the radial basis interpolation method based on global weak formulation (RPIM) is a relatively stable method, but needs a large amount of calculation; better results can be obtained using the collocation with a small amount of the polynomial basis function added, simple and practicable.

Abstract: Tri-sectional regenerative air heater is used widely because of its compactness and better performance. Study on the matching analytical calculation method of heat transfer is rarely carried out because of the complicated heat transfer process. This paper developed a model to solve the heat transfer calculation of multi-sectional regenerative air heaters, which usually have several layers. Then we designed the computational procedure to carry out the model. One example of a tri-sectional regenerative air heater with hot layer and cold layer shows the effectiveness of the algorithm, and the results suggest that this approach is valid. The impact of leakage on performance of the regenerative air heater was discussed. There is a negative linear correlation between exhaust gas temperature and air leakage, and boiler efficiency has a nearly linear negative correlation with air leakage.

Abstract: Numerical simulation was conducted to study self-sustained oscillation and chaos of natural convection in horizontal fluids layer heated from below. The numerical simulation was conducted using SIMPLE algorithm with a QUICK scheme. Discrete time series was analyzed to study stability problem. Correlation dimension was calculated, their frequency characteristics were analyzed and chaos attractor was extracted. The results showed that oscillation appeared when Ra was over 2×10⁴ and chaos appeared when Ra was over 5×10⁶. When parameter was varied, chaos appeared. Strange attractor was used to describe chaos system. Fractal dimension of strange attractor was 1.19. Saturated embedding dimension of phase space reconstruction was 5. The time delay was selected for 5.

Abstract: Main steam temperature regulation is one of the most demanded control loop in modulating control system of thermal power plant. According to the characteristics of main steam temperature, an intelligent control technology has been proposed. To eliminate lag and inertia in main steam temperature regulation process, the intelligent control technology integrates several advanced algorithms. The application effects in several ultra-supercritical thermal power plants prove that the control technology has outstanding robustness and excellent adaptability in both variable load and steady state condition.

Abstract: This paper is based on 30 ground source heat pump projects measured data which is comparative analyzed, using SPSS statistical software for modeling and find out several key independent variables that influence the system COP and the linear relationship between them. Verify this model in order to lay a foundation for unified evaluation criterion for the ground source heat pump energy efficiency ratio.