Applied Mechanics and Materials Vols. 291-294

Abstract: The chiller performance decrease with the system operating is inevitable, however, determining how to predict when it will happen, and how to identity the degree of performance decline, it is very important to solve these actual problems for chiller high efficiency operating and daily management. This paper developed a fault diagnosis model based on thermodynamic analysis of chiller’s refrigeration cycle and heat transfer analysis of its heat exchangers, taking three projects which involve different source sinks, namely, air source, ground source and reclaimed water source as cases study, described the fault diagnosis method and implementation steps through these engineering cases, the results show that the fault diagnosis model provides a newly simple and effective approach for chiller operation monitoring.

Abstract: As the air conditioning energy consumption of the date center has increasingly become the focus of attention, reformation for the energy consumption and exploration for the suitable combination model of the air conditioning system have significance in energy saving. This paper makes a program design for the air-conditioning system of a data center in Beijing, makes an analysis of the system operation mode and uses the concept of exergy efficiency to optimize the air conditioning system in order to achieve maximum efficiency.

Abstract: This paper adopts the Matlab language to program the SMER dehumidifier. Through simulation calculation, the effect of air, inlet air humidity and temperature on SMER was carried out, the relationship among the three factors was also gotten. The influence of humidity on the optimal air volume according to the maximum of the dehumidification is more than the temperature influence. The paper can provide certain basis for the optimal air volume setting.

Abstract: One of improving refrigeration performance of adsorption chiller methods is optimizing adsorption chiller structure. A new type of adsorption chiller was proposed in this paper, which obtained two adsorbers, evaporator, condenser and vapor valves between adsorber and evaporator and between adsorber and condenser. The vapor valve was the very important component of the adsorption chiller, which was controlled by pressure difference of both sides of vapor valve. Compared with normal adsorption chiller, the vapor valve replaced the tubes and vacuum valves between adsorber and evaporator and between adsorber and condenser. It can reduce the total equipment size, and decrease the pressure loss of refrigerant flowing in the refrigeration system. Working mechanism of vapor valve and working process of adsorption chiller were investigated, and the theoretical calculation of adsorption chiller was carried out. These works were important foundation for design of adsorption chiller.

Abstract: The running state of the fan has significant influence on the safety and economy of the power plant unit, so it is necessary to monitor the fan performance and running state in real time. According to the basic theory of the fan, there is a stable, good nonlinear mapping relation between the inlet pressure difference and flow, which can be utilized to monitor the flow of the fan. Thus, the fan differential pressure - flow curve model is established by the optimized BP neural network and the modified Support Vector Machine (SVM). The fitting error shows that the improved SVM model is better. Finally, the on-line fan monitoring system software is established by using Visual Basic (VB) language and Matlab programming based on the improved SVM fan differential pressure - flow curve model, which can accurately monitor the fan operation.

Abstract: A numerical model to improve the air-conditioning system of vehicle cabin taking into the cabin air moisture and its transport by the airflow within the enclosure cabin is described. An efficient computational fluid dynamics(CFD) technique is using the “realisable” model. The temperature and humidity fields in the passenger cabin are investigated individually under having or no body moisture. The temperature in the vehicle cabin taking into account human moisture is lower than no taking into account moisture 0.5 °C. The human dispersing moisture effect significantly on the humidity, which lead to the humidity is elevating and the humidity in vehicle cabin is corresponded hygienic standard.

Abstract: This paper briefly introduced the design and operation features of capillary air conditioning system, put forward multi-objective optimization problem in hydraulic calculation process, using genetic algorithm to solve multi-objective optimization problem and established a capillary air-conditioning system hydraulic calculation model. The problems of hydraulic calculation were transformed into the problems of multi-objective optimization Pareto optimal solution using genetic algorithm (GA). And GA was applied to illustrate corresponding to specific model. The optimal specific frictional resistance under the different flow conditions was described here.

Abstract: Urea-SCR catalytic converter can effectively reduce the NOx emission of diesel engines, but meanwhile catalytic converter will cause some pressure loss in the exhaust system, which has negative influences on the engine performances. In this paper, the method of theoretical analysis calculated the pressure loss of the SCR catalytic converter, and designing a new type of exhaust gas pipe. Through the test to meet the design requirements,the results can provide a reference for optimum design of SCR catalytic converters and assembling.

Abstract: Most of solving method for reliability growth model parameters is to structure maximum likelihood function and extremum on the likelihood function. When the maximum likelihood method is adopted for the evaluation and optimization of parameter, because of the effect of iterative initial value, the classical one is not easy to converge to the global optimal solution. Evolutionary programming (EP) algorithm used in this paper , its feature is to establish the fitness function, find great value point to determine optimization model of the parameters optimal solution, and it is not necessary to find extreme value and estimate initial value of the optimization variable to obtain global approximate optimal solution. In order to better ensure global optimal solution, to further ensure the accuracy of the equations, a parallel operation and retain the best individual and other methods are used in evolutionary programming algorithm. The new method for solving the optimization parameters can achieve a better balance in the solving efficiency and convergence performance and better combined optimization methods with maximum likelihood estimation method. The validity and correctness of the optimization method is verified in the last of the paper through the experimental data in the reliability growth process of a solid rocket motor.

Abstract: Review is made of research on LPG engine and hydrogen fueled or enriched engine. Based on the positive features of hydrogen and the current limitations associated with the LPG intake liquid injection engine, a hydrogen enriched LPG intake liquid injection engine was developed, and its performance and exhaust emission characteristics are investigated.