A new type of tidal unit-vertical shaft tubular turbine is designed with high efficiency, large flow rate and low water head ,which has large power under the 2~3 meters water head. According to the data of the being installed tidal units and principles of tubular turbine’s design, the high efficiency vertical shaft tubular turbine was designed under large discharge and low head, which was suitable for the tidal power station. The design also considered the requirements of turbine’s size and the details of flow through the whole flow passage were attained. The turbine’s property was predicted by the 3-d numerical simulation software on the whole flow passage. Moreover, the influences of vertical shaft’s sizes were analyzed. And the terminal of vertical shaft with or without transverse brace and longitudinal brace were analyzed to get the influence. Considering the hydraulic performance of various methods, the best guide vane opening was chosen. The results show that, the turbine unit has the best performance on efficiency, hydraulic loss, etc. with the guide vane opening 62°, meeting the power station’s design requirements. The results show that the optimal designed flow passage’s efficiency reaches up to 88.4%, the flow rate becomes much larger and the power reaches 174.63kW. Without partial vortex, the flow pattern is smooth through the whole passage also with lower hydraulic loss.
In the industrialized cultivation process of fungi, CO2 concentration control system is a nonlinear, time-delay and time-varying system, which is difficult to establish a precise mathematical model. Considering the situation, CO2 concentration prediction model that based on neural network was built, and a fuzzy controller was proposed further based on the prediction model. Finally, matlab/labview based online forecast model was finished, and it is verified that the prediction system has higher prediction accuracy with robust character. It also provides a new approach to control key environmental factors under more favorable conditions for mushroom growth.
A numerical method has been developed to analyze the solid-liquid two-phase flow with coarse particles in vertical pipes. Based on the numerical study, a concept of lifting efficiency has been suggested to describe the efficiency of lifting solid particles by the moving liquid. The lifting efficiency can be defined as, where vs is the average velocity of the solid particles and vl is the average speed of the liquid. It was found that when the liquid speed is lower than 3m/s, the lifting efficiency is increased when the liquid speed is increased. On the other hand if the liquid speed is more than 3m/s, the lifting efficiency will decrease if the liquid speed increases. It was also found that the speed of the particles will decrease if pipe vibration frequency is increased. However the lifting efficiency remains unchanged compared with the stationary pipes.
In order to effectively extract nonstationary and nonlinear fault signature of hydropower units’ signals, a new method, based on Hilbert–Huang transform (HHT), is proposed. This method is used to carry out EMD (Empirical Mode Decomposition) analysis and Hilbert transform of signals firstly and then extract Hilbert spectrum to provide a basis for signal feature extraction. The vibration signal of upper brackets in hydropower units has been put forward with experimental analysis. The results suggest that the EMD can decompose vibration components in different frequency domain, which has intuitive physical meaning. Moreover, Hilbert spectrum also has a good resolution in time domain and frequency domain. Thus, HHT can be used to depict the fault signals effectively and lay the foundation of the fault pattern recognition.
As a formal modeling and analysis method, colored petri nets (CPN) fits to construct formal model for software/hardware system with lots of communication and parallel/synchronous sharing behavior. Then behavior analysis of system function and performance based on the CPN model can be unfolded to verify the system feasibility. The CPN model of a kind of new CMP architecture shared multi-channel L2 Cache (AUMCC) is constructed in this article. Processing simulating of instruction set is deeply penetrated on the AUMCC CPN model, and analysis based on simulating results well verifies the feasibility of AUMCC architecture.
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