Advanced Materials Research Vols. 516-517

Abstract: Based on CFD software, Navier-Stokes equations, Sparlart-Allmaras turbulence model and the structure mesh method, the whole flow passage of Francis turbine were 3-D numerical simulated. By CFView, the distribution of velocity vector and static pressure in the flow passages through flow field were analyzed, which explained the shortcomings of design and its incidental problems of lower discharge capacity and lower efficiency. Consequently the improvement of the runner alone was promoted, and which could be proved to be good results.

Abstract: Through three-dimensional mechanical design software Pro/E to build a spur gear solid model, using ANSYS software for the gear mesh, as well as the constraints imposed by the most unfavorable load to determine the location of the discussion, in order to get accurate finite element analysis model. By analyzing, this shows that the effectiveness of the application of ANSYS in gear calculation.

Abstract: To slove the measurement disputes of the central heating system of Shengli Oilfield base, ensure the accuracy and impartiality of measurement, this paper presents the ways of using portable ultrasonic flowmeter for testing and verifying the flowmeter of heating systerm of Shengli Power Plant. By calculated that, the maximum error of the heating flowmeter reached -17.50%,resulting in the Power Plant loss of more than nine hundred thousands GJ in heating period of one year, not only caused huge economic losses to the Shengli Power Plant, but also greatly increased pollution of the living area of Shengli Power Plant. Therefore, we give some comments and suggestions to the insufficient of heat-metering in the Shengli Power Plant, it laid the foundation for the management reform and further standardization of heat-metering.

Abstract: The air-conditioning system is a source of energy consumption and consequently, it has a strong influence on the fuel consumption, the engine load and the pollutant emissions. The air-conditioning system has to be accounted for in the energy balance under the hood. This system is composed of a variable displacement compressor including an internal regulation valve. In this paper, we model a complete system step by step. We build the compressor system and gradually add components so as to end up with the complete system. The simulation results shows that when the suction pressure becomes at some point smaller than the regulation pressure, the valve controls the compressor displacement and tends to reduce it in order to maintain a certain level for the suction pressure. It will be easier to observe the influence of the regulation valve on the complete refrigerant loop system.

Abstract: Heavy-duty gas turbine is used widely in power generation industry for many advantages. Gas turbine exhaust system is an important component of the gas turbine. The work to study the exhaust system was less in the past. In fact, structure design of the exhaust system has important influence on performance and life of the gas turbine. In this paper, the three-dimensional structural model of gas turbine exhaust system is built, the thermal field and stress field for the exhaust system are analyzed by using finite element method (FEM). The maximum stress and distribution characteristics of stress field, the highest temperature and distribution characteristics of thermal field in the exhaust system are computed. These provide a reliable basis for reasonable design and safety evaluation of the exhaust system in gas turbine.

Abstract: Turbocharging technique has played a critical role not only for improving automotive engine performance, but also for reducing fuel consumption and exhaust emissions both in Spark Ignition and Compression Ignition engines. In the research described in this paper, a 1D centrifugal compressor model has been developed for simulating turbocharger flow and performance. The model takes into account energy conservation and transfer which includes the losses determined from the compressor geometry. The losses including incident loss, friction loss, clearance loss, backward loss and volute loss were simulated by the thermodynamics model, rather than from the characteristic performance curves obtained experimentally. The proposed model was validated against experimental data and it showed simulating and experimental results are in very good agreement at three different rotational speeds, in particular near the surge line, though the deviation begins to increase as mass flow rate goes up. With current results, it has suggested the proposal is suitable for predicting the compressor performance curves such as outlet pressure, efficiency and losses for any centrifugal compressor. In addition, surge line obtained from the simulation result can be used to define stable operation range.

Abstract: In order to obtain the vibration characteristics of the turbocharger rotor system, its natural frequencies and vibration modes are approached by the experimental method and the finite element method. The modal parameters are obtained by modal tests, and are calculated by the finite element method with the software ANSYS8.0 at the meantime. The influence is approached mainly for the oil film stiffness of the floating-ring bearings and the rotor’s rotating speed. The FEM result is certificate compared with the modal test result. The influence of the rotating speed is greater on the rotor natural frequency than that of the bearing stiffness. It provides the theoretical basis for turbocharger’s vibration control and structure improve.

Abstract: Exciting force's accurate measurement is crucial to the structure-born sound radiation. And the force sensor is calibrated by the dynamic force calibration equipment. Exciting force is accurately measured on the ribbed cylinder’s forced vibration and sound radiation. Based on the steady sine and random white noise exciting, the frequency response functions of the acceleration and sound pressure are obtained. Results obtained from the two methods are shown to be in good agreement with each other. According to the acceleration’s frequency response functions and sound pressure’s frequency response functions, it is obvious that the peak frequencies in the two frequency response functions are corresponding to each other. And the correspondence relationship could be used to help control the radiated noise.

Abstract: The gear is widely used in aviation engines to transmit power. The gear faults affect somwhat the safety of the engines and aircafts. The vibration signal of gear is a carrier of gear situation information, it contains a lot of information about normal gear or faulty gear, so an effective signal process way is the important method of diagnosis the gear in good situation or not.The hybrid method of Wigner-Viller distribution (WVD) and singularity value decompositio(SVD) was introduced and applied to diagnose the gear faults in this paper. The results show that the hybrid method investigated is successfully to ascertain the gear fault.

Abstract: Taking a type of ceramics for daily use horizontal high pressure grouting machine‘s main frame as the object of study, established its CAD model and in order to study the stress and strain, conducted finite element static analysis on it . The analysis results can provide a reference for design of the main frame, and have a large general engineering and practical value.