Advanced Materials Research Vols. 516-517

Abstract: Thermal decomposition characteristics of two kinds of calcium based organic compounds-calcium propionate and the product of the modified calcium hydroxide by propionic acid-under O2/N2 atmosphere and O2/CO2 atmosphere are investigated through thermogravimetric analysis. Thermal events of CP and MCP are divided into three segments. The second and the third ones for the two compounds are similar. O2/CO2 atmosphere reduces mass loss rate peak of the second segment and postpone the third segment. O2 concentration of 10 % is inadequate for a fast and sufficient reaction. When O2 concentration is enriched to 20 %, the whole process is shifted towards lower temperature zone. Further heightening O2 concentration to 30 % or 40 %, the effect is not remarkable.

Abstract: The objective of this study was to determine the best method for waste thermal energy recovery from internal combustion engine (ICE). There are several technologies that can be used to accomplish this objective such as turbocharger, combined turbines, Stirling engine, Seebeck effect and Rankine cycle. Two elements that need to be taken into consideration in order to choose the best technology for waste heat recovery system are the complexity of the system and the method to utilize waste heat energy from engine. After a reviewing some of past research work, it was determined that Rankine cycle appears to be one of the best technology to recover waste heat from ICE. Improved design in Rankine cycle configuration and selection of the highest evaporation enthalpy working fluid are said to be necessary. This study finally proposed that future related research should focus on recovering waste heat from the engine waste heat (engine block) only. This is predicted to give an additional power output of approximately 10%.

Abstract: The aim of this paper is to find the energy distribution principle of open feedwater heaters under transient conditions. Taking a heater as the example and employing the first and second law of thermodynamics, thermodynamic models for vapor-liquid, mixture-liquid and liquid-liquid heaters were established and applied. And its energy distribution is obtained. The results indicate that that some error occurs when models for steady conditions are used at transient states. And the drain-cooler section has the largest error. The major factor is the exergy stored in exothermic fluid.

Abstract: The thermal diffusion similitude should be well considered during the numerical simulating of its distribution in power plants or nuclear power stations. The distribution near the waterspout is well related to the initial grid’s size. The bigger the initial grid is, the faster the thermal diffusion. Reasonable initial grid should be related to thermal discharge and flow velocity. Five different grid’s sizes are adopted to simulate the constant diffusion phenomenon in a rectangle water channel, the currents near the waterspout, the thermal diffusion near or away from the waterspout are discussed in this paper, and a rational size of initial grid is proposed to relative researchers.

Abstract: With the increasing depth of coal mining, problems of high temperature thermal damage in mine become more and more serious. A high heat tunnel thermal environment case is numerical simulated in the presented work, PMV (Predicted Mean Vote) indices are using to predict the thermal comfort of environment, velocity field, temperature field and PMV values field in high heat tunnel had been obtained. The simulation results indicated while the inlet air velocity is 0.7 m/s, the temperatures in most tunnel area are below 26 °C and the thermal environment conforms to the Coal Mine Safety Regulation in China.

Abstract: In recent years, with the rapid development of supercritical units also brings some serious problems, for example, due to the oxide skin exfoliation of boiler tube caused many boiler tube explosion accidents. Aiming at this problem, the paper first introduced commonly used steel and its resistance to steam oxidation, and then the metal oxide skin formation and exfoliation mechanism is studied. These findings have a certain reference value for the power plant safe and economy operation.

Abstract: The homogeneity test is the first stage to revise the climate records. Its accuracy will directly affect the follow-up work. The classic method SNHT (Standard Normal Homogeneity Test) can only be applied in climatic sequences obey normal distribution, but lots of non-normality climate sequences need to be examined. In this paper, the Smirnov Test was introduced to test the homogeneity of the temperature series, which is a classical method for distribution test, and it can apply for the temperature sequences obey any distribution. The homogeneity test results by testing Chongqing Municipality's temperature sequences show that: the Smirnov Test is better than SNHT

Abstract: A series of abnormal phenomena emerging in normal operation conditions of the medium speed pulverizers in a 600 MW unit are introduced. The effects of the primary air (PA) mass flow and nozzle ring passage area on the pulverizer rejects (PRs) discharge are analyzed. The results indicate that the root cause of all these abnormal phenomena is the lower nozzle PA velocity led by the narrowed nozzle passage area during the nozzle ring reformation. The problem is solved by changing the nozzle ring back to the original one. The experiences in this document can provide evidence and reference for pulverizer operation adjustment and PA nozzle ring reformation design.

Abstract: In conventional turbofan aero-engine designs, the effective way of improvement of engine efficiency is through the increasing of overall pressure ratio and improving of combustor inlet gas temperature, but the further incresement of compressor overall pressor ratio is constricted by high pressure compressor outlet allowed temperature. The improvement of combustor outlet temperature is limited by turbine allowed inlet temperature during take-off and climbing. An intercooled core can be designed with a significantly higher overall pressure ratio also with reduced cooling air requirements, providing a higher thermal efficiency compared with a conventional core. Through the basic analysis of performance of intercooler aeroengines. It indicated that the intercooled aero-engines can decrese the feul consume clearly and have a further potential in future civil aircraft application.

Abstract: Economic lot and scheduling problem is one of the focuses in the international engineering field. Aiming at several kinds of products and sets of production lines, this paper introduces a production model, which is based on the principles of artificial intelligence and introduces random factors as time changes, such as market demand and production line equipment. Besides, this paper puts forward a dynamic heuristic search production schedule method, and the simulation results show that the effectiveness and predictability of this method.