Applied Mechanics and Materials Vols. 260-261

Abstract: In this paper, the characteristics of a two-way ball valve orifice are researched. By means of modeling and analyzing of the trajectory of valve opening angle, a conclusion was drawn that there was trigonometric function relationship between the orifice area and opening angle of a ball valve. Based on this, the bench tests are conducted with the spraying system with 6 nozzles. It can be seen that there is a good agreement between prediction model established and experiment by the method of border points checking, the absolute error is in the range of 0~0.002mm2. With further research, there is a marked logarithmic relationship between the orifice area of a ball valve and flow of the sprayer, the correlation coefficient is 0.9952.

Abstract: Energy demand is steadily increasing in the world. People face challenges to meet this demand. Smart grid technology is helpful to renewable energy utilization and thus is drawn more and more attention. This paper makes a comparison of several indicators among five countries or districts from 2002 to 2010. These indicators include energy use indicator, GDP per unit of energy use indicator, net energy imports indicator, CO2 emissions indicator, fossil fuel energy consumption indicator, and Alternative and nuclear energy indicator. From the trend analysis of these indicators, it can be seen that developing countries especially China has a rapid increase in energy consumption and have a high environment protection pressure. Hence smart grid development is an urgent task for China. Some issues in the development of smart grid are discussed and some policy suggestions are presented.

Abstract: In this paper, we developed stator and rotor shapes of interior permanent magnet type brushless motor for automotive cooling device in order to obtain better performance than the prototype. Response surface methodology (RSM) is employed in this paper as an optimization method. Finite element computations have been used for numerical experiments on geometrical design variables in order to determine the coefficients of a second order model for the RSM. The optimum design results confirm that desirable improvements in cogging torque, back-EMF and THD are achieved.

Abstract: Distributed resources and microgrids may be designed for power supply in some rural areas. Basic design requirements based IEEE 1547 and optimal plan methods of the microgrids are focused in this paper. Some technical specifications and requirements to design and plan the microgrids are introduced. An optimal plan model is discussed to provide the size of a hybrid, renewable energy generation based the microgrid with the goal of minimizing the lifecycle cost while satisfying the required capacity shortage probability of power supply. The conception and the configuration of a microgrid cluster are put forward. Moreover, the energy modeling software for the microgrids, HOMER is applied in the study based the microgrid project information and data at an island in the southern China.

Abstract: The article deals with the identification of a chemical structure of pyrolysis liquid occurring by the thermal degradation of tyre debris within the temperature interval from 500°C to 650°C and the temperature increase steps of 50°C in individual experiments and with the use of analytical methods GC/MS, FT-IR and the elementary analysis. The measured FT-IR spectra indicate the representation of functional groups included in measured samples. They could be used for the determination of basic chemical properties. There were changes in the chemical composition monitored as well as the creation of functional groups in the pyrolysis liquid on the basis of FT-IR spectra and GS/MS outcomes.

Abstract: The article presents a detailed analysis of brown coal, rubber and polyethylene pyrolysis in a horizontal reactor of a thermic facility. It is a facility continuously processing entry materials flowing in the amount of up to 150 Kg.h ^-1 and with the total maximum heaters’ output of 200 kW. The attention has been paid to the thermal input of the pyrolysis process and to the description of physical-chemical processes in time and the reactor space. The objective has been to find out the best combination of entry material and process conditions from the point of view of pyrolysis energy intensity. The article specifics are based on the fact that the mentioned processes have been analysed in a large facility having the semi-production characteristics, not within a laboratory system used usually in this kind of research (DSC).

Abstract: The publication deals with the comparison of mathematic models that simulate heat transfer by radiation and of models of spectral characteristics of the burnt gases. The heat transfer in the combustion chamber with the shape of rectangular cross-section of 200 x 288 mm and 1,000 mm high has been numerically analysed by means of the individual models. A low pressure burner of the ejection type and of the power output from 20 to 40 kWs is located in the lower part of the combustion chamber. As the heating gas, methane is used. The interest is especially focused on the evaluation of the radiation intensity in the combustion chamber and on the heat fluxes to the walls that are predicted by the models. Results of the P1 and Discrete Transfer models and results of the Gray and MultiGray models of spectral characteristics of the burnt gases have been compared. A part of the research is also the recommendation dealing with the individual models usability.

Abstract: Supermarkets and hypermarkets require a huge amount of energy to maintain chilled and frozen food in product display cases and cold storage rooms and thermal comfort in the whole building. Systems exploited require very large refrigerant charges for operation and suffer significant leakages. The challenge for advanced systems, based on equipment which reduce TEWI, suggests the proposal of carbon dioxide: a natural working fluid. This paper deals with a feasibility study of a refrigerating system for a big hypermarket in Sicily based on a three-stage transcritical cycle working with carbon dioxide which is compared with an alternative system composed of two cycles operating as a binary refrigerating plant: a top cycle working with propane and a bottom cycle working with carbon dioxide. The cold is produced at two temperature: - 15°C and -35°C. In both alternative systems, cold at -15°C will be delivered to display cases, cold stores etc. by means of a secondary loop into which circulates a refrigerant fluid (e.g. an ethylene-glycol solution), while cold at -35°C will be delivered by another loop into which circulates directly liquid carbon dioxide. Main results obtained demonstrate the effective feasibility of plants which seem suitable for commercial refrigeration, bearing in mind that is of capital relevance the best operating efficiency of the secondary loop system. This depends mainly on thorough design and building of the secondary loops, especially for those which op erate at lower temperature.

Abstract: With kitchen residues and cattle manure as raw materials, in temperature (36±1°C) adopt the way of the batch type fermented for kitchen residues and cattle manure, we will have a comparative research between independent anaerobic fermentation and mixed anaerobic fermentation. The results of the experiments show that the gas production and COD removal rate by the anaerobic fermentation of cattle manure independent would be superior to kitchen residues, the optimal effect is the anaerobic fermentation of kitchen residues mixed with cattle manure in all aspects .In this experiment all the kitchen residues are rice, vegetables, meat, eggs and other food all that have been after cooked, containing a large number of fat and salt, such condition is not suitable for the growth of microorganism. The time of gas production is only nine days and gas production rate is extremely low, only 1500ml accumulative gas production, But cattle manure’s accumulative gas production is 3028ml, COD removal rate was 21%, COD removal rate by mixed anaerobic fermentation of kitchen residues and cattle manure can achieve 60.92%.

Abstract: Based on the composition and characteristics of steelmaking dry-dedusting dust and oxide scale in hot-rolling mill, cold briquetting ores were processed by dust and oxide scale, and applied to converter vanadium recover. The research results show that, hot metal carbon oxidation rate and vanadium oxidation rate increased with the increased use of cold briquetting ores, and the TFe content of vanadium slag reduced, the consumption of iron and steel materials decreased. Not only can effectively use the steelmaking mill and hot-rolling mill waste, but also can improve the product quality of the converter vanadium recover.