Advanced Materials Research Vols. 614-615

Abstract: Nanoparticles in nanofluids are in the form of nanoparticle clusters caused by aggregation. In order to calculate the thermal and electric conductivity of the nanofluids, the growth process and three-dimensional space structure of the nanoparticle cluster in the host fluid is simulated, and then the thermal and electric conductivity of the cluster are calculated with the resistance network method. The thermal and electric conductivity of the nanofluid are calculated based on the simulated thermal and electric conductivity of nanoparticle clusters, the volume fraction of nanoparticle clusters to the nanofluid as well as the liquid molecule adsorption layer of the nanoparticle. The simulation method is validated by experimental data.

Abstract: This paper is to simulate the internal flow field in the impeller and the volute of 9-19No.4A fan under different operating conditions. Based on CFD theory and standard two-equation turbulent model, the simulations of turbulent flow between the impeller and the volute under different operating conditions are performed by using the flow calculation software CFX. Numerical results are utilized to perform detailed flow visualization. The results indicate that the fan performance curve of the experiment agree with those of numerical simulations.

Abstract: This paper is based on the method of volume of fluid function (VOF) and founds numerical wave tank similar to real sea condition using business software CFD and its function of second development, proceeds numerical simulation of linear wave and second-order stokes and compares them with the theoretical value. The numerical result corresponds to the theoretical result, which lays the foundation for further research of interaction between wave and power generation device.

Abstract: The columnof the wave-power generating device is analysed through theoretical analysis using finite element software. The deformation and stress under maximum wave impact force is calculated by harmonic analysis, the result of which indicates that deformation and stress of the maincolumn, which under huge wave impact calculated by Morison theory, is very small. The stress of the column generated by wave load is less than its material yield strength, which indicates that the safety performance meets the requirements.

Abstract: Because the most of crude oil has the nature of "three-high" in China and the natural aging of crude oil in the part of oil field, the transmission of crude-oil has reduced, and the oil refining has increased in oil field, Thus the majority of pipelines laid in china are running at a low-flowrate. Analysis of the problems in the running of low-flowrate pipeline: with the temperature drops up, the viscosity increases; the accident of condensate tubes very easily occurs; the turnover point increases; the pressure load of pipeline increases; the supply of heat is shortage, the reliability of equipment is reduced; costs increases and so on. There is proposing the main operation mode to solve the pipeline in low-flowrate, including intermittent transportation, the transportation of mixing light oil, oil and gas batch transportation, the transportation with adding pour point depressant and so on, and has discussed the instability of the running of hot pipeline in the low-flowrate.

Abstract: By the ultrasonic preventing and removing fouling test-bed, study on the effect of velocity on ultrasonic propagation characteristics by experiment. Keep the liquid temperature, ultrasonic emission frequencies and power constant. In the heat exchange tube, measure the ultrasonic sound intensity at the inlet and outlet of the pipeline, when the liquid velocity changed. The results show that, at normal temperature (25°C), the input power and ultrasonic frequency keeping constant, the ultrasonic sound intensity decreased gradually firstly and then increased with the change of the liquid velocity changed from 0m/s to 2m/s. The ultrasonic sound intensity attain minimum when the liquid velocity about 0.45m/s.

Abstract: FEA(Finite Element Analysis) has been used in the stress analysis of two geometry sizes of opening and offset nozzle, corresponding standards has been included, and the results show that the strength of the cylinder is fit for safety requirement. The stress analysis also shows that the stress distribution principles are not dependent to the sizes of the opening, but closely to the positions. At the same time the magnitude of stress is relative to the size of the opening and the nozzle. So, stress analysis should be conducted to every offset opening and nozzle to ensure the safety of the cylinder.

Abstract: Maximal operation pressure, minimal allowed pressure, number of source points have greatest impact on flow and reliability of pipe network. The change of the three design parameters before and after conversion are analyzed. Through the analysis of problems on the artificial gas pipeline network in Changchun City, point out that removing extra loops is the main optimization means. The hydraulic calculations have been made for optimized pipe network, and compares the flow capacity and hydraulic condition of the pipe network before and after conversion.

Abstract: The role of mangrove trees in reducing the tsunami waves during the tragedy of Andaman tsunami occurred on December 26, 2004, has been credited and these indirectly raise awareness about the role of mangroves forest as a natural breakwater on the beach. This paper will focus on the mangrove trees from Avicennia and Rhizophora species in order to identify the methods of breaking wave energy that has been carried out by the mangrove roots and stems. Analysis of the mangrove roots coordination pattern had been conducted by gathering data at study site located at Kemaman, Terengganu and the data had been plotted in Gambit software for simulation purpose in Fluent Inc software. Hence, the simulation result showed that the ratio of wave height and velocity reduction may vary depending on factors such as the species of the mangrove trees and density of the roots that grow around the tree. Consequently, the study will be examining the waveform that is mitigated by the both species Avicennia and Rhizophora using turbulent flow and experiment will be conducted to validate the data obtained by the simulation.

Abstract: The measurement method of the power plant circulating water flow was investigated. When the characteristics of the circulating water system was calculated through characteristic curve intersection, circulating water pumps were generally assumed to be in parallel and the resistance of main pipes was ignored. In addition, the circulating water flow of each unit was considered equivalent. This method was accurate only when the distance of main pipe and circulating water pump is shorter. Therefore, the hydraulic computation method combining with pipe network has been proposed with the long distance condition. This method calculates accurately the circulating water flow of each unit. This research lays the foundation for the optimum vacuum calculation of the whole plant.