• Journal of Korean Society of Water and Wastewater
• /
• v.21 no.5
• /
• pp.581-587
• /
• 2007

In order to suggest the methodology for improving the equality of flow distribution in a distribution channel, wet tests were carried out for pilot plant which was scaled down to 1/8 of full scale distribution channel being operated in domestic K_water treatment plant. The correlation between various hydraulic variables and their effects on the equality of flow distribution was evaluated through wet tests using pilot plant. From the results of wet tests, the longitudinal baffle with orifices was installed in the distribution channel, the equality of flow distribution was improved on the condition that the Froude number in pilot plant was similar with that in the full scale channel. Also, the opening ratio of the orifices on the longitudinal baffled did not have influence on the performance of the equality of flow distribution when the average flow velocity and Froud number were relatively low (Froude number ${\fallingdotseq} 0.01$). In the other hand, the performance of the equality of flow distribution was improved with increasing the opening ration of on the longitudinal baffle under conditions of relatively high average flow velocity and high Froud number(${\gtrsim}0.1$)

• Journal of Korean Society of Water and Wastewater
• /
• v.20 no.5
• /
• pp.667-676
• /
• 2006

This study was conducted to evaluate the effect of longitudinal baffle on hydrodynamic behavior within a certain full-scale sedimentation basin (flow rate per basin; $1,000m^3/d$). Comparative experimental investigations have been carried out on the sediment removal efficiencies and the sludge deposit distribution in the baffled and un-baffled sedimentation basin, respectively. From the results derived in the baffled and un-baffled sedimentation, the turbidity removal rate in the baffled sedimentation basin is about 38% higher than that in un-baffled. Also, the height of sludge deposit in the baffled sedimentation basin is approximately 20% lower, and the sludge concentration is 10% higher than those in un-baffled sedimentation basin. In order to explain the experimental results and investigate the effect of longitudinal baffle in more detail, we conducted Computational Fluid Dynamics (CFD) simulation. From the results of CFD simulation, the flow, especially in the near of outlet orifice, was more stable in the case of longitudinal baffled sedimentation basin than that in un-baffled basin. Also, it could be concluded that the longitudinal baffle made a fully developed flow more effective for sedimentation.

• Journal of Korean Society of Water and Wastewater
• /
• v.21 no.6
• /
• pp.755-761
• /
• 2007

Disinfection performance in clearwell is generally measured by CT, which is expressed by $C{\times}T$. C is represented by disinfection concentration, and T is represented by $T_{10}$ which means 90% contact time in clearwell. In order to improve Disinfection performance, augmentation of $T_{10}$ is required. Guide wall has been generally used to improve $T_{10}$ because $T_{10}$ changes according to flow field. In this study, porous media is proposed instead of guide wall, and disinfection performance between guide wall and porous media wall are compared. Flow field and $T_{10}$ in each clearwell are investigated as well. Improved Disinfection performance appear in case of porous media wall compare to guide wall, and best performance occur in porosity factor ${\beta}$ 1e+4.

• Journal of Korean Society of Water and Wastewater
• /
• v.22 no.1
• /
• pp.113-120
• /
• 2008

A large majority of clearwell must be modified with maintaining the present baffles since they were underground built with the material like concrete. Therefore it is unreasonable to apply the previous research in clearwell modification which is studied with the assumption that distance between baffles is constant. In this study, internal short-circuiting estimation method (ISEM), which has the advantage of being applied at any condition, is applied to evaluate modification of A clearwell and modify B and C clerwell which have unusual characteristics. After analyzing the hydraulic efficiency at current state, modifications, where baffles, intra basins and diffuser walls are additionally installed, are considered and evaluate using ISEM. And the effect of intra basin and diffuser wall on $T_{10}/T$ is estimated and application feasibility of ISEM is evaluated. The improvement of intra basins is almost same with that of baffles. Also, short-circuiting in effluent zone can be reduced with the same level of channel zone if intra basin is added in effluent zone. However, effect range is restricted to the next channel zone. Diffuser wall can obtain the lower ISI than minimum ISI of cases where baffles and intra basins are installed. Therefore, additional improvement of $T_{10}/T$ value can be expected after $T_{10}/T$ value converges maximum only using baffles

• Journal of Korea Water Resources Association
• /
• v.38 no.3 s.152
• /
• pp.189-198
• /
• 2005

This study showed that numerical simulation can be effectively used to analyze discharge capacity according to the form and arrangement of the lock gate of a tidal power plant. For the numerical simulation, FLOW-3D with Reynolds-averaged Navier-Stokes equation as a governing equation was used. This study found that improvement of apron length and approach angle of guide wall of the lock gate causes differences in discharge capacity of $10\%$ or more. In addition, there was a difference of discharge capacity caused by the connecting structures of the drainage gate and hydraulic turbine structure and the side slope at the end of apron. This study also showed that hydraulic investigation to enhance a discharge capacity is needed when the lock gate is designed and that numerical model experiments can be a useful analysis tool to design the drainage structure, as well as the hydraulic model experiment.