Advanced Materials Research Vols. 614-615

Abstract: Aiming at the problem of gas-steam combined cycle cold-end system, the system of the circulating water and condenser are considered as a whole. Based on the basic thermodynamics principles, and considering the coupling characteristics of the output load with gas turbine and steam turbine, providing an analytical method that is used to determine the optimal value of condenser vacuum pressure and circulation water flow rate, the optimum operation mode is obtained with the systematic view. And take a 9F-class circulation unit as an example, the operating mode has been verified by adopting this method. The results indicate that the economy of unit increased after optimization.

Abstract: A good deal of electricity consumption can be attributed to air-conditioning refrigeration systems. The percentage can be significantly higher if a cooling system is operating at low performance levels due to the presence of faults. The wavelet transform moves data from a time domain to a frequency domain with the wavelet as the basic function giving the localized features of the original signal in the fault detection. It is well known for its capability of treating the transient or time-related varying signals. The fault of heat load increase of the air-conditioning room can be predicted by wavelet transform through the test. Fault prediction in air-conditioning refrigeration system by wavelet transform can avoid defects of the conventional methods.

Abstract: The new large power hydraulic spring driver used in high voltage switch is integrated with hydraulic valve and cylinder. The hydraulic valve is put into cylinder in the rectified structure so as to change all the axial seal to radial seal. Advanced control principle and main configuration make the new hydraulic spring driver many characteristics such as excellent performances, complete functions, reliable operation, good technics and small cubage. Expecialy, the self-protection ability solves the important tecnnique problem.

Abstract: Based on Methanol and diesel special combustion mode, a control strategy of methanol/diesel dual fuel engine on turbocharged DI diesel engine was introduced according to different operation conditions. A method of judging engine load by measuring intake manifold pressure was put forward. Bicubic interpolation method was adopted to optimize the control MAP for ensuring the coincidence between look-up table data and actual conditions. The feasibility of the control strategy is verified by bench test. And the results of test show that the economic performance of this dual fuel engine got a considerable improvement.

Abstract: To study the flow characteristics of the electrically controlled injection device (abbreviate ECID), 3D static and transient numerical simulation were studied during the injection process of electrically controlled injection device using computational fluid dynamic software FLUENT. Simulation results revealed that the flow of ECID was influenced by the injection valve diameter, valve lift and the pressure difference; gaseous fuel was still left after inlet valve closed; mixing quality of gaseous fuel and air gradually improved along the intake manifold.

Abstract: The supercritical turbine, changed low pressure rotor’s blade in site, bear vibration over-proof seriously because of unbalance, reached rated speed after dynamic balance in site. The vibration of low pressure Ⅱshaft’s bear was still over-proof. And the bear vibration phase was anti-phase with the shaft vibration not only anti-phase but also in-phase. It was found that the bear vibration was highly related with the anti-phase component of shaft vibration after running date analysis. And the bear vibration was reduced obviously after the anti-phase component of shaft’s residual unbalanced mass reduced by dynamic balance in site.

Abstract: In the existing biomass briquette production market, the screw extrusion-type machines are applied at the earliest. However, the shortcoming of the easily-worn screw head limits their application and large-scale development. In this paper, the main reason of the impact on screw life can be identified by the force and motion analysis of molding biomass. Therefore, theoretical basis for the improvement and optimized design of the molding machine can be provided. Furthermore, new paths which can increase the machine efficiency, reduce production costs and increase biomass briquette production can be found.

Abstract: A new method for correlation test was presented to study the reliability of a heavy duty vehicle, and the method can combine the real customer usage with the enhancement test on proving ground, and avoid the test blindness. Aiming at the data that were tested on the typical pavements of the customer and enhancement roads of proving ground, the rain-flow counting method was used to obtain the load distribution matrixes , according to the correlation equation, the cumulative fatigue damage and loading spectrums of the 90% customer and proving ground were optimized and calculated. Through the correlation analysis, the pavements enhancement coefficient and the reliability test specifications were obtained. The test results indicate that the new specifications can predict the potential failures of the load carrying structures quickly, shorten the test cycles.

Abstract: By the research of expert system design method and rough set theory, an expert system of equipment fault diagnosis has been established. The paper focuses on the description of designs on knowledge database, inference engine and explanation facility of the expert system and taking the air compressor vibration fault diagnosis as an example to analyse and validate. It shows that expert system can improve the system’s performance, improve system’s capacity and efficiency of diagnosis when rough set theory is applied to fault diagnosis.

Abstract: Calculating navier-stokes equation to study oil film pressure characteristics of three oil wedge bearing by using CFD software. Studied how to the three oil wedge sliding bearing effect on rotor stability, and analyzing oil film pressure characteristics of three oil wedge sliding bearing and cylindrical bearing. The results showed that three oil wedge bearing is much more stable than the cylindrical bearing, it is more advantageous to the running rotor and unit at stable working than the cylindrical bearing in the same oil film thickness and inlet pressure.