The numerical analysis of two-dimensional transient flow around the obstacle with rotated square cross sections was carried out. The obtained velocity distributions for each time step and each rotation angle were imaged to provide data for CNN(convolutional neural network). Both classification and regression neural networks were used for prediction of rotation angle. As results The classification method incorrectly predicted the rotation angle in only 2 of the 470 images. The regression method predicted the rotation angle errors within except 2 out of 470 images. From these facts, it could be concluded that both methods can be sufficiently applicable to the flow analysis.

Recently, car industry trend is downsizing, a lean-burn engine, green car and cost cutting. A turbocharger is the key components to improve fuel efficiency and power. This research is to study on the flow analysis in the performance analysis for change rotating speed of turbocharger turbine with three different rotating speed in the turbine. After measuring real design features, modeling, velocity distribution, pressure distribution and temperature distribution are conducted numerically. Torque and power are compared with three different cases in order to analyze the performance for turbine. Finally, optimum power is determined with the sequence of case 1, case 2, and case 3.

본 연구에서는 원형실린더 후류 와류에 의한 진동을 제어를 위해 적용되는 나선형 뱃전판의 효율향상을 위해 다양한 회전각에 대해 모델실험을 실시하였다.실험은 회류수조에서 레이놀즈수 Re=4.0×10³,Re=5.5×10³ 및 Re=7.0×10³에서 균일유입유동에서 2-프레임 그레이레벨 상호상관 PIV기법을 이용하였다.실험결과 원형실린더와 뱃전판을 부착한 실린더와의 비교를 통해..

The paper concerns numerical study of fully developed laminar flow of a Newtonian water and non-Newtonian fluids, 0.2% aqueous of sodium carboxymethyl cellulose(CMC) solution in eccentric annuli with combined bulk axial flow and inner cylinder rotation. Pressure losses and skin friction coefficients have been measured when the inner cylinder rotates at the speed of 0～200 rpm. A numerical analysis considered mainly the effects of annular eccentricity and inner cylinder rotation. The present analysis has demonstrated the importance of the drill pipe rotation and eccentricity. In eccentricity of 0.7 of a Newtonian water, the flow field is recirculation dominated and unexpected behavior is observed. it generates a strong rotation directed layer, that two opposing effects act to create two local peaks of the axial velocity. The influences of rotation, radius ratio and working fluid on the annular flow field are investigated.

Numerical solutions are presented for compressible fluid flow past a rotating elliptic cylinder in a medium at rest at infinity. Flowfields and acoustic waves emitted from rotating elliptic cylinder are directly simulated by the Lattice boltzmann method formulated by the Arbitrary lagrangian eulerian scheme. The flowfield is almost periodic after the calculation fully developed and studied by means of streamlines and equi-vorticity lines and by means of drag, lift and moment coefficients. The positive and negative vorticity is alternately occurred at the edge by those large vortexes. The acoustic waves propagate synchronizing with the rotation and increase with M3.5 of rotational speed of elliptic cylinder.

버터플라이 밸브는 선박에서 냉각수와 유류 계통 등에 범용으로 널리 사용되고 있다. 이 연구에서는 유량조정에 따른 배관계통의 버터플라이밸브 후류 유동특성을 규명하기 위하여 입자영상 유속측정장치를 이용하여 밸브개도에 따른 유선과 속도벡터 분포에 관한 정량적인 데이터를 확보하였다. 또한 밸브 주위 유동장의 압력성분을 고찰하기 위하여 개폐각도를 6가지 경우로 변화시켜 정압을 측정하였다. 그 결과 실험관 벽면에서 측정된 압력의 분포는 디스크가 전개 상태인 0˚에서 45˚까지는 입구 압력은 일정한 상태로 거의 변화하지 않았으나 약 60˚ 이상에서부터 압력 상승과 점차 급격한 변동현상이 나타났다. 특히, 75˚ 부근에서는 상류에서 급격한 압력 상승 경향을 보인 반면 하류 측은 압력변동이 적게 나타났다.

Heat transfer and flow characteristics in a pipe in which the rotating cutting tool for boring a underground pipe without digging were considered in this study. The amount of heat generation due to the friction between the rotating cutter and pipe wall, mixing flow of air and water injected to cool down are the two important factors to design the boring machine. Computational fluid dynamics analysis using the Eulerian mixture model and the standard k-ε turbulence model was used to analyze the complex phenomena in a pipe during the process. Results show that pipe wall temperature decreased with increasing the cooling water inlet velocity. It is also shown that pipe wall temperature was lowered when the cutter rotation speed was increased until 600 rpm. There was no further cooling effect over 600 rpm.

This study was conducted to evaluate capability of dyeing wastewater treatment for 3 type reactors. These reactors were Packed Bed Reactor(PBR), Fluidized Bed reactor(FBR) and Moving Media Complete Mixing Activated Sludge reactor(MMCMAS). Experiments of PBR and FBR were performed by various packing ratios and organic loading rates, experiments of MMCMAS were performed by various organic loading rates In order to obtain SBOD_5 removal efficiencies of more than 90%, the F/Mv ratios of PBR, FBR, MMCMAS were 0.11 ㎏BOD/㎏MLVSS·d, 0.12 ㎏BOD/㎏MLVSS·d, and 0.37 ㎏BOD/㎏MLVSS·d, respectively. So MMCMAS system which has more active microorganisms showed better capability of organic removal and also stronger dynamic and shock loadings than those of PBR and FBR. In PBR and FBR, the media packing ratio of 20% showed better performance of organic matters removal effciencies than 10% and 30%, but sludge production rate at media packing ratio of 30% was relatively lower than that of 10% and 20%. When more than 90% organic matters removal efficiency was obtained, the ratios of attached biomass to total biomass at PBR, FBR, MMCMAS were 89∼99%, 87∼98%, and 54∼80%, respectvely. The ratio of attached biomass to total biomass was low in MMCMAS. This was formation of thin biofilm due to shear force between rotating disc and water. The average sludge production rates(㎏VSS/㎏BODrem.) of PBR, FBR and MMCMAS were 0.20, 0.29 and 0.54, respectively.