Applied Mechanics and Materials Vols. 316-317

Abstract: In order to solve the problem which is very common when we use a solar water heater for a shower but the hot water can not come immediately because of the cooled water remained in the pipeline, a no-pump cycling water-saving equipment is designed based on a pressure-regulated suction device, temperature acquisition control circuit and a water-saving box. The kinematics and mechanics parameters are confirmed on the result of calculation and software simulation, and are tested by doing physical experiment. It can make it come true to economize the water and energy for solar power heater.

Abstract: By the analysis of the current technical conditions and existing problems, some improvements are carried out on the urban sewage source heat pump unit. are as follows: Refrigerants side switch sewage source heat pump system, dual-purpose heat exchange for evaporating and condensing & wastewater can enter the unit directly are of the main features of the improved units. Some important techniques, such as inverter screw compressor and variable compressor inner volume ratio are used to the improved unit at the same time. From the authoritative organization’s test, the improved sewage-source heat pump unit has an excellence performance in the nominal cooling and heating conditions.

Abstract: Based on a detailed chemical reaction mechanism including gas phase reaction and surface catalytic reaction, adopting the CFD software to simulate the combustion process of premixed hydrogen-oxygen in a sub-millimeter burner, and introducing a calculating model of criterion number of heat transfer, a comparative analysis of surface catalytic conditions is performed to find out the heat transfer characteristics during combustion process. The simulation results show that the effects of inlet velocity on Nux number vary regionally when gas phase reaction combined with surface catalytic reaction. As inlet velocity increases, Nux number firstly increases and then decreases in low velocity. While in high inlet velocity, the Nux number of entrance region is in the negative half shaft that means the direction of heat transfer has changed. Inlet temperature has comparatively less effects on Nux number in micro catalytic combustion process under the computational conditions. When the temperature is fixed, the Nux number with catalytic is higher than those without catalytic and the difference is more obvious in lower temperature. Key words:Micro combustion, Catalytic combustion, Criterion number of heat transfer, Dimensionless analysis

Abstract: Chaos exists widely in nonlinear dynamic systems, it behaves as chaotic oscillation, voltage collapse, etc. Power system in essence is a strong nonlinear system, with certain conditions there will be completely chaotic phenomena.The main research progress of chaotic control approaches and application and the prospect is outlined in this paper. This article also presents shortcomings and challenges of chaos studies in power system.

Abstract: Wind power is a kind of special electric power, because of the volatility of the wind, making voltage stability has become an important research problem wind power system must facing with. Therefore, according to the relevant current research status and the main existent problems of wind power system, expounding the difference of voltage stability between the conventional energy sources and the wind power, and the influence of voltage stability to the power system which caused by wind power system. This paper mainly from the definition and the classification to introduce the voltage stability; from the research contents and methods of static and dynamic voltage stability to analyze power systems which contains wind farms, especially emphasizing the necessity of the bifurcation theory used in power system contains wind power. Finally points out that the research trend of analysis and improvement in this area.

Abstract: The protective effect of isolated operation Mode on Micro-grid was studied in this paper employing the method of contrast analysis. A model of Micro-grid system powered by wind and hydro was built using Matab/Simulink to simulate the two modes of isolation and connection under the circumstance of public power grid fault. Results show that the isolated operation mode of micro-grid is effective and necessary.

Abstract: In ordered to realize dynamic simulation of working process in the rotary engine, a spark-ignition rotary engine is chosen as the research object, the detailed calculated models have been established including combustion model and turbulence model. With numerical simulation, same important information in the cylinder is obtained, such as the velocity, temperature fields and flame propagation. Furthermore, the effect of pocket location on the flame propagation is analyzed. The results show that under the calculating condition, when the pocket is located at the rear of rotor, the rate of combustion and the peak pressure are better than that of other cases, and NO emissions increases accordingly. This study provides some theory guidance for the determination of best pocket location under different working conditions.

Abstract: this paper constructs a new type experimental investigation of a heat storage solar water heater -water/air source heat pump double stage coupling capillary network radiation heating system, The system is a combination of a solar clean , reproducibility and water/air source heat pump energy saving property, is a kind of energy saving, pollution-free energy efficient system. In qinhuangdao local climatic conditions test capillary network radiation heating, water source heat pump, air source heat pump operation parameters, analyzes the system as a whole, it is concluded that the operation of heat storage solar water heater - water/air source heat pump double stage coupling capillary network radiation heating system is suitable for in qinhuangdao climate condition in application.

Abstract: This paper describes a miniature Stirling engine driven by double swash plates. Based on domestic and foreign analysis method of the thermodynamic characteristic theory of the Stirling engine, the establishment of a relevant mathematical model and performance on the numerical analysis were presented. The results include V-t diagrams, P-V diagrams, P-n diagrams, h-n diagrams and the effects of phase angle between the compression and expansion volumes on the engine’s power and efficiency. This paper offers invaluable guide for similar design.

Abstract: This paper discusses an on-going effort of collaboration between the Missouri Industrial Assessment Center of University of Missouri, and a large industrial organization to institutionalize best practices of energy efficiency within the organization’s global network of manufacturing companies. It also outlines a computer-aided framework developed to help such effort, which closely follows the ISO50001 standard, and represents a comprehensive knowledge base and project tool, providing support to the processes, tasks and documentation of the cycle of continuous improvement.