Advanced Materials Research Vols. 605-607

Abstract: This article studies the flow pulsation of de-icing fluid pump station. First, find the factors affect the extent of flow pulsation through kinetics analysis. Then, base on the summary of the existing pulsation suspension methods (Include combining work of several pumps with an equal original phase differences, changing a single acting pump with a double acting pump), we put forward the method by optimizing the structure of the reciprocating pump to inhibit the flow pulsation. Use system simulation software AMESim to simulate the effect of these methods. Ultimately get the conclusion that the flow pulsation can be controlled at about 12% through these methods. All these works may provide a reference for the design of a de-icing fluid pumping station.

Abstract: A single-zone HCCI combustion model coupled with chemical reaction kinetics mechanisms was set up by AVL-BOOST and CHEMKIN module based on a variable lift and timing (VLT) gasoline. In order to achieve HCCI combustion, the negative valve overlap (NVO) strategy was used to raise the temperature of mixed air in the simulation. In this paper, the HCCI combustion was compared with the conventional SI combustion, then the feasibility of using single-zone model to simulate the HCCI combustion was verified and the HCCI operation region was predicted under specific speed, compression ratio, air-fuel ratio conditions by this model.

Abstract: In this paper, a new type of hydraulic test bed is developed which can be used for performance testing of hydraulic valves, hydraulic motor and hydraulic pump. The composition structure diagram of hydraulic system, power supply system, and the signal flow diagram of data acquisition system were designed. The characteristics of the LabWindows/CVI development tools and the usage of Prodave MPI/IE 6 network communication tools were introduced, also the database storage and access technology in LabWindows/CVI environment. It was proved through the practical application that the test bed is reliable and has the merit of higher precision and automation level, and simple operation.

Abstract: Control valves are generally present whenever fluid flow regulation is required. The control valve reliability is critical to the control quality and safety of a plant. An improved dynamic and static valve behaviour would have a major impact on the process output. In order to assess the dynamic performance of the control valve, a computer model of an electro-hydraulic control valve is developed. And the control valve characteristics are investigated through the use of mathematical simulations of the control valve dynamic performance. The results show that the electro-hydraulic driven control valve, which is developed to regulate the mixed-gas pressure in combined cycle power plant, can meet the challenge of the gas turbine.

Abstract: Convection heat transfer in a plate channel periodically fitted with sintered copper porous ribs attached to a copper plate was numerically studied. The local thermal equilibrium model was adopted in the energy equation to evaluate the temperature of fluid and solid. The effect of porosity, Reynolds number and heat flux applied to the copper plate on the heat transfer characteristic of the porous media was investigated respectively. The numerical results show that the heat transfer can be enhanced by increasing Reynolds number, decreasing the porosity and the heat transfer enhancement of the porous media took effect significantly when subjected to high heat flux. Detailed development of the porous media temperature field and the Nusselt number of the wall as a function of Reynolds number for different porosity and heat flux were also presented.

Abstract: The internal structure of magnetorheological fluid could change under external magnetic field, as well as its dielectric constant and magnetic conductance. A theoretical model of electromagnetic wave propagation in MRF was established and the basic formula of transmissivity was deduced. Theoretical simulation shows that the electromagnetic wave transmissivity decreases with the increasing of dielectric constant of magnetorheological fluid, and increases with the magnetic permeability. Theoretical analysis indicates that the change of its structure and dielectric magnetic properties of MR fluids is the main cause for the fact that the transmittance could be adjusted under external magnetic field.

Abstract: The doubly fed induction generator(DFIG) has been widely used in wind power generation system. It can alters speed of the rotor according to change of the wind speed, then contains the maximum tip speed ratio, in order to capture the maximum power from the wind energy. And the output frequency will not chang with the speed of generator. This paper studys the maximum wind energy capturing of DFIG. The theory analysis and simulation results based on MATLAB/Simulink demonstrate this control strategy is convenient and efficient.

Abstract: The fluid state of the straight conical draft tube is simulated by using Fluent software. The distributing condition of the axial pressure and flow speed inside the straight conical draft tube is analysed and the recovery coefficient of the corresponding running condition is calculated, when the diffused angle is changing.

Abstract: Gas velocity in cyclone separator is measured by testing with laser Doppler velocimeter in this paper. The measuring results indicates that tangential velocity, axial velocity, radial velocity of air distribute following some certain rules, reasonable selected structure parameters can improve separating efficiency

Abstract: To improve the impeller safety and reliability of extractable explosion-proof contra-rotating axial fan for mine local ventilation, Extractable Fan FBDC№9.0/2×30 was taken as the research object, and an approximate three-dimensional finite element computation model was built by using ANSYS software. The stress and displacement were calculated, too. By testing, the fan works stably. The air quantity is 655-978 m3/min, total pressure, 3443-412Pa, static pressure, 3314-118Pa. And the highest static pressure efficiency is up to 70.35%, A-weight Specific Sound Level is 17.5dB. Furthermore, the intension and stiffness of the impeller meet requirements. Sample test and field using show that the computation and the model of this impeller are right. Through reasonable design, the impeller of contra-rotating axial fan with equally-thick circular arc blade profile and ordinary hot-rolling low-carbon steel blades has the intension and the stiffness which meets demands, and the air performance reaches higher level.