Advanced Materials Research Vols. 655-657

Abstract: The modified Hiroyasu soot model is widely used to describe the soot emission from diesel engine, but diesel methanol dual fuel engine is different from diesel one. In order to obtain quantitative comparisons with experiments, a new soot emission model was presented, which was formulated to incorporate the effects of both chemical kinetics and turbulent mixing. The model was applied to simulate soot emission from diesel methanol dual fuel engine. The calculating results indicate that the predicted soot emission from the new model agrees well with the measured data.

Abstract: For matching various working condition of ship propulsion system, a modified mean value model of a large-scale low-speed directly reversible marine diesel engine is put forward. A starting and braking torque module is added to the conventional model. A new friction model which considers static friction is adopted. So, the new model can run smoothly across all propulsion working condition, such as starting, running, braking, reversing, etc. The dynamic simulation models of propeller running across four quadrants and ship longitudinal motion are given too. The 5S60MC marine diesel engine equipped on a 76000DWT bulk carrier is taken as an example. The simulation results show that steady data of diesel are in good accordance with test-bed data, and dynamic data match to ship sea trial data in crash stop condition. The best is to read these instructions and follow the outline of this text.

Abstract: The drag reduction characteristics of riblet structure on aerofoil blade of centrifugal fan were numerically simulated with Fluent. Riblet structure still has good drag reduction effect on the surface of aerofoil blade. The best drag reduction effect has been gotten with appropriate riblet structure size, with the greatest drag reduction efficiency of 9.65%. And under the design flow of the fan, the drag can be reduced by 2.96%. The mean velocity of near-wall region on riblet surface has a significant increase than smooth surface. Turbulent kinetic energy and turbulent intensity are lower than smooth surface obviously, the drag reduction effect of riblet structure on aerofoil blade is verified. The present results can be used to provide a valuable reference for optimization of centrifugal fan blade modification.

Abstract: Several influence for the soot and NOx emission of methanol and n-heptane dual fuel combustion is advised, using homogeneous charge compression ignition model in CHEMKIN-PRO. The calculating results indicate that methanol plays an important role in the course of soot formation, but the effect of methanol is smaller for NOx. With the increase of methanol quantities, the soot formation is reduced and the soot particle diameter is smaller; if the fuel equivalence ratio is small, the influence of methanol is obvious to NOx emission. If the fuel equivalence ratio ≥ 1.0 , the trend of NOx emission changed. With the increase of methanol, NOx emission early increased, and decreased late.

Abstract: The waterflooding development of Oilfield fringe area and scattered blocks are restricted by the existing pipe network design and pipeline transportation distance and so on. In order to improve the development effect of these blocks, by using advantages of ESP including high head, range capacity and mature technology, technology of exploiting and waterflooding in one well with ESP was discussed. Then, some key problems were settled such as sand prevention, sealing, downhole monitoring of process parameters, structure design and so on, and three process schemes were summarized including exploiting the upper layer and waterflooding the lower layer, exploiting the lower layer and waterflooding the upper layer and downhole pressurized injection. The technology proposed by this article has achieved good results proved by field applications. The success of the technology provides an economical and reliable energy supply technology for oilfield development, and has a broad market prospect.

Abstract: In order to reduce the energy consumption and the hydraulic noise, the paper modifies the hydraulic pump/motor and designs a novel high-speed filling valve for the system, which is normally open and large-diameter. The modified pump/motor and the valve constitute the power unit. In the ANSYS/FLUENT the paper simulates numerically the flow field in the high-speed filling valve. By the use of ANSYS/LS-DYNA the paper analyzes the impact stress of the valve core. According to the simulation results, the power unit is optimized. Tests show that the noise decreases significantly in the vehicle utilizing the valve.

Abstract: In order to solve the problem of the flow-induced vibration under high temperature and high pressure when opening or closing the steam trap, sleeve was designed and three-dimensional numerical simulation of the internal turbulent fluid field was performed by using Fluent of computational fluid dynamics software. When sleeve is installed ,the results show that flow-adjusting characteristic is equal percentage for different travels , meanwhile, meet the rules that low flow rate is at small opening and large flow is at maximum open degree. It is benefited to suppress the generation of pressure fluctuation and pipe-vibration. This paper will provide a reference for the design of more excellent performance steam trap.

Abstract: In the precondition of calculating the flow field around the blade with the singular distribution way, the hydraulic characteristic after cutting the mixed-flow blade is calculated by CFD software , the optimum value of output in HL240-WJ50 water turbine and the influence of the flow field are found out by using that way: when the cutting measure of the cutting tip is 9.4mm, the output of the rotating wheel is increased 5.7% and the characteristic of cavitations isn’t clearly worsened. The improved water turbine blade is applied to the capacity-increasing rebuild of the small electric station. The cutting measure is 5 percent of the average of the blade’s upper canopy and lower rim. The power of the rotating wheel is improved from 232KW to 253KW after cutting, and the output can reach the requirement of the electric station. So the lesser economy to the trailing-edge can get into the better goal of rebuilding, that is suitable to rebuild the small hydraulic power station’s wheel.

Abstract: Atomization characteristic has great impact about combustion efficiency, ignition performance, and outlet temperature field of combustor. Obtained atomization characteristic about spray particle size and spray cone angle using LDV/PDPA system and the relevant software. The results indicated: particle size decrease rapidly with increasing air and tends to stabilize, Spray cone angle does not change with the air pressure. These experimental data have provided reliable basis for the nozzle group design, development and operation.

Abstract: The shaft center of steam-turbine generator, showing relative position of shaft and bearing bush, would changed when jacking oil pump or turning gear started, raising speed and loading carrying. The change of bear carrying, oil film rigidity and clearance variation in flow passage of steam-turbine generator could be deduced through measuring shaft center position and analyzing its variation to working conditions, which would be helpful for treating vibration malfunction cased by deficiency of oil film rigidity, steam flow exciting and rubbing.