http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
김종부,신명국,성낙환,최문정,김경주,이동석 강원대학교 산업기술연구소 2000 産業技術硏究 Vol.20 No.A
This experiment was done to investigate the leaching and adsorption properties of heavy metals on porphyry. The comparison with respect to the leachability of heavy metals from porphyry between the Korea Standard Leaching Test (KSLT) and the Toxicity Characteristic Leaching Procedure (TCLP) was carried out. The fractional composition of leachate and the total concentration of heavy metal of porphyry were studied through Sequential Extraction Procedure (SEP) and EPA Method 3050. Adsorption experiment of porphyry has pointed out that the optimum dosage of porphyry for 50ppm Pb was over 10g/L, the effective particle size for absorption was below 200 mesh and the optimum pH was about 7. From the Freundlich' adsorption equation, l/n was 1.0722, and k was 0.0041. After adsorption, the fractional composition of Pb was changed. The exchangeable, carbonate, reducible fractions were increased, and the organic fraction was not changed, and the residual fraction was decreased.
The influence of water level and flow rate on vortex occurrence in pump sump
Ming Guo,최영도 한국마린엔지니어링학회 2019 한국마린엔지니어링학회지 Vol.43 No.2
A pump sump is an indispensable facility in cargo ships, irrigation, drainage, agriculture and industrial processes. The water intake conditions around suction bell mouth significantly affect the performance of the whole pumping system. However, there are different types of undesirable vortices that occur in pump sump, such as submerged vortex and air entraining vortex. Accompanying with the variety of vortex, noise and vibration also appears. In this study, a scaled down model of a pump sump was designed and constructed. The occurrence of the vortex was the concentrated target which was investigated under various suction pipe inlet conditions. With different water levels, flow rates and a fixed distance from the bottom to suction pipe bell mouth, detailed experiments were conducted. Additionally, a computational fluid dynamics (CFD) analysis was performed, verifying the influence of water level and flow rate on visualization and formation of vortex obtained in the experiment. The CFD analysis results were compared with those of the experiment.
Ming Guo,최영도 한국유체기계학회 2019 한국유체기계학회 논문집 Vol.22 No.3
As it has been proven, the design of impeller meridional shape directly influences the performance of multistage centrifugal pump. In this study, the five parameters of the double-arc meridional shape design method were selected as the design variables. A multi-point hydraulic optimum design method of impeller meridional shape for multistage centrifugal pump performance improvement was presented. The maximum hydraulic efficiency and effective head were chosen as the objective functions. The design of experiment method was applied to generate different impeller meridional shapes and a total of 50 sampling models were generated using the Latin Hypercube Method. The Reynolds Average Navier Stokes equations were adopted to conduct the numerical calculations. To validate the performance improvement of the optimal design model, efficiencies of the optimal design model at flow rates of 0.8Qref, 1.0Qref, and 1.2Qref were compared with the original reference model. The optimal efficiencies under the three operation conditions increased by 1.9%, 1.6%, and 0.9%, respectively. In addition, the CFD analysis of a two-stage multistage pump assembled by impellers, continuous diffuser and return vanes was conducted. The cavitation performance was also validated.