과부하 4방향 합류맨홀에서의 손실계수 산정을 위한 실험 연구

류택희,김정수,윤세의 한국수자원학회 2016 한국수자원학회논문집 Vol.49 No.12

In general, manholes installed as urban drainage facilities are a variety forms such as straight path manholes, 90 degree bend manhole, three-way combining manhole, and four-way combining manhole. In particular, the surcharged flow at a four-way manholes installed in the downstream of urban sewer system is the main cause of the urban inundation caused by the energy loss. Therefore, it is necessary to analyze the flow characteristics and estimate the head loss coefficients at surcharged four-way combining manholes. The hydraulic experimental apparatus which can change the manhole shapes (square, circle) and flow ratios were installed to estimate the head loss coefficients. In the experiments, two inflows (Qm, Qlat) were varied from 0 to 4.8ℓ/sec and 24 combinations were tested in total. The flow ratios Qlat/Qout were varied from 0 to 1 for a total flow Qout (Qout=Qm+2Qlat) of 2, 3, 4, and 4.8ℓ/sec, respectively. The variation of head losses were strongly influenced by the lateral inflow because the head loss coefficient increases as the flow ratios Qlat/Qout increases. It was estimated head loss coefficients of the circular manhole is slightly lower than those of the square manhole. However, there was no significant difference of head loss as discharges change. The range of head loss coefficients at four-way combining manhole according to the change of the lateral inflow ratio was estimated to be 0.4 to 0.8. Also, the relation equations between the head loss coefficients (K) and the lateral inflow ratios (Qlat/Qout) were suggested in this paper. 일반적으로 도심지 배수시설로 설치되는 맨홀은 중간맨홀, 90° 접합맨홀, 3방향 합류맨홀 및 4방향 합류맨홀 등 다양한 접합 형태를 가지고 있다. 특히 도시유역의 중․하류부에 주로 설치되는 4방향 합류맨홀에서의 과부하흐름은 에너지 손실을 발생시켜 도심지의 침수피해를 가중시키는 주요 원인이다. 그러므로 과부하 4방향 합류맨홀에서의 흐름특성 분석 및 손실계수의 산정이 필요하다. 본 연구에서는 현황조사 결과를 고려하여 수리실험 장치를 제작하였으며, 맨홀 및 관경은 하수도 시설기준을 준용하여 1/5로 축소 제작하였다. 선정된 실험조건인 맨홀 형상 조건(사각형, 원형), 유출유량(Qout)에 대한 측면유입유량(Qlat)의 비(Qlat/Qout) 및 실험 유량(2.0, 3.0, 4.0, 4.8 ℓ/sec)을 변화시키면서 실험을 실시하였다. 실험결과 측면유량비가 증가할수록 손실계수는 증가하였으며, 사각형 맨홀보다 원형 맨홀에서의 손실계수가 다소 낮게 산정되었다. 그러나 유출유량 변화에 따른 손실계수의 변화는 미미하였다. 측면유량비에 따른 과부하 4방향 합류맨홀의 손실계수는 0.4~0.8로 산정되었다. 또한, 측면유량비 변화를 고려한 4방향 합류맨홀에서의 손실계수 산정식을 제시하였다.

과부하 맨홀의 손실계수를 고려한 도시지역 침수해석

이원,김정수,윤세익 한국수자원학회 2015 한국수자원학회논문집 Vol.48 No.2

일반적으로 XP-SWMM은 맨홀을 하나의 절점으로 간주하여 절점의 형상과 크기에 따른 국부손실의 영향을 고려하지 못하기 때문에 침수면적을 과소 산정한다. 그러므로 과부하 맨홀 내에서의 손실계수를 고려한 해석 방안 및 손실계수의 적용에 따른 침수해석에 관한 연구가 필요하다. 본 연구에서는 유량변화 및 맨홀 형상 변화에 따른 수리실험을 실시하여, 과부하 맨홀(원형, 사각형)에서의 손실계수를 각각 0.61과 0.68로 산정하였다. 또한 XP-SWMM을 이용하여 군자배수분구를 대상으로 산정된 손실계 수의 적용 유무에 따른 침수면적의 변화특성을 분석하였다. 분석 결과 손실계수를 적용하면 침수면적이 3.5ha 증가하는 것으로 나타났다. 이는 손실계수 적용에 따라서 맨홀에서의 월류량이 증가하기 때문이다. 대상유역에 손실계수를 적용하였을 경우 실제 침수면적과의 일치율은 약 58%로 나타났으며, 손실계수를 고려하지 않았을 경우의 일치율은 약 40%로 나타났다. 그러므로 과부하 맨홀에서의 손실계수를 고려한 2차원 침수해석의 결과는 도시지역의 침수 위험지역을 정확하게 파악하기 위한 기초적인 자료로 활용이 가능할 것으로 판단된다. In general, XP-SWMM regards manholes as nodes, so it can not consider local head loss in surcharged manhole depending on shape and size of the manhole. That might be a reason why XP-SWMM underestimates inundatedarea compared with reality. Therefore, it is necessary to study how we put the local head loss in surcharged manhole in order to simulate storm drain system with XP-SWMM. In this study, average head loss coefficients at circular and square manhole were estimated as 0.61 and 0.68 respectively through hydraulic experiments with various discharges. The estimated average head loss coefficients were put into XP-SWMM as inflow and outflow energy loss of nodes to simulate inundation area of Gunja basin. Simulated results show that not only overflow discharge amount but inundated-area increased considering the head loss coefficients. Also, inundation area with considering head loss coefficients was matched as much as 58% on real inundation area. That was more than simulated results without considering head loss coefficients as much as 18 %. Considering energy loss in surcharged manholes increases an accuracy of simulation. Therefore, the averaged head loss coefficients of this study could be used to simulate storm drain system. It was expected that the study results will be utilized as basic data for establishing the identification of the inundation risk area.

동조액주관댐퍼의 가진진폭별 오르피스감쇠특성에 대한 연구

유기표(You Ki-Pyo),유장열(You Jang-You),송창현(Song Chang-Hyun),김영문(Kim Young-Moon) 대한건축학회 2009 大韓建築學會論文集 : 構造系 Vol.25 No.6

With the production of light?weight and high?strength construction materials and the advance of structure design techniques, various forms of high?rise buildings are being constructed. These buildings cannot help considering the effect of wind load. Because wind velocity grows higher with the increase in height from the ground, high?rise buildings respond sensitively to the wind and make vibration. In order to reduce the vibration, many additional mass devices are being developed. Recently, supplementary dampers using tuned liquid column damper (TLCD) are being developed actively. This study purposed to measure the amplitude response and the head loss coefficient of TLCD for different sizes of excitation amplitude according to the aperture ratio of orifice. In addition, we obtained the head loss coefficient according to the length of the horizontal column at natural frequency determined by the length of the vertical column and the horizontal column of TLCD. Thus, this study analyzed for the amplitude response and head loss coefficient of tuned liquid column damper according to the porosity of orifice while vibrating amplitude and natural frequency change. In addition, as the natural frequency of TLCD is determined by the length of the vertical and the horizontal column, we examined the variation of the head loss coefficient of orifices in adjusting natural frequency according to the length of the horizontal column. In the results of experiment, the larger vibrating amplitude was, the lower the head loss coefficient was. Under the same porosity, the head loss coefficient decreased by up to 4 times by 1mm of vibrating amplitude and 20mm of vibrating amplitude. Porosity and vibrating amplitude had a considerable effect on the head loss coefficient. When the length of the horizontal pipe increased, the overall head loss coefficient decreased by around 1.5-2 times.

장치형 비점오염저감시설의 유입수로 분기각과 단면비율에 따른 수두손실계수 분석

송영석,이희섭,박민규,박무종 한국방재학회 2014 한국방재학회논문집 Vol.14 No.4

Various NPS (Non-Point Sources) pollutants flow into a stream after rainfall event that directly causes water quality deterioration. NPRE (Non-point Pollutants Removal Equipments) is necessarily emphasis for water quality improvement. Existing installed NPREonly consider conditions of location or digestion capacity that causes low removal efficiency. In this study, head loss coefficient areanalyzed by branch angle and ratio of channel flow area of inflow channel when polluted stream water flows in NPRE. Branch angleof inflow channel (30o, 45o, 60o, 75o, 90o) and entrance channel on ratio of channel flow area of inflow channel (20%, 30%, 40%) areanalyzed Using Two-dimensional hydraulic modeling. Result from decreasing branch angle of inlet and increasing entrance channelon ratio of channel flow area of inlet that showed decreasing head loss coefficient. 강우발생시 각종 비점오염물질은 우수유출수와 함께 하천으로 유입되는 수질저하의 직접적인 원인으로 비점오염원 저감시설의 필요성이 대두되고 있다. 기존에 설치된 장치형 비점오염저감시설의 경우 단순히 입지조건이나 처리용량만을 고려한 설계로서 처리효율이낮은 실정이다. 본 연구에서는 오염된 하천수가 장치형 비점오염저감시설로 유입시 유입수로 분기각과 단면비율에 따른 수두손실계수를 분석하고자 한다. 분석모형으로는 2차원 수치모델을 활용하였으며 유입부의 분기각(30o, 45o, 60o, 75o, 90o)과 본류수로에 대한 유입수로 단면비율(20%, 30%, 40%)에 대하여 분석을 진행하였다. 분석결과 유입수로의 분기각이 감소할수록, 본류수로에 대한 유입수로 단면비율이 증가할수록 수두손실계수는 감소하는 것으로 나타났다.

Analysis of Transient Flow in a Piping System

Hyuk Jae Kwon 대한토목학회 2007 KSCE journal of civil engineering Vol.11 No.4

Transient flow in a piping system was studied using both experimental and computer models. Two different computer models, the method of characteristics model and the axi-symmetrical model, are utilized and discussed. Experiments for transient flow in a piping system were conducted to verify the results of the computer models. It was found that the energy decay is underestimated if the Darcy-Weisbach friction coefficient/is used for the analysis of transient flow. Therefore, the equivalent head loss coefficient CL is introduced and experimentally determined as 0.3 which is several times larger than the Darcy-Weisbach friction coefficient?for the present experimental setup. The value of a parameter K in the axi-symmetrical model is calibrated using the results of experiments. The parameter κ is 0.22 for the present experimental setup and is smaller than the value used in previous studies.

동조액주관댐퍼의 고유진동수와 오러피스에 대한 감쇠 특성

유기표(You Ki-Pyo) 대한건축학회 2010 大韓建築學會論文集 : 構造系 Vol.26 No.4

Orifices are installed on the horizontal tube of a tuned liquid column damper in order to increase the coefficient of head loss of the damper. Because such orifices control the flow of the horizontal tube, there is a variation in the level of water in the vertical tube. In general, only one orifice is installed in the middle for controlling the flow of the horizontal tube. In this study, examined the damping characteristic of a tuned liquid column damper according to porosity, the number of orifices installed and natural frequency. Amplitude response was lower when orifices were not installed than when they were, and the lower amplitude response increased the head loss coefficient. Compared to when only one installed, when two orifices were installed amplitude response decreased by up to 7%.

수치모형을 이용한 과부하 사각형 맨홀에서의 손실계수 산정

김정수,임가희,임창수,윤세의 한국방재학회 2011 한국방재학회논문집 Vol.11 No.3

Energy loss at manholes, often exceeding friction loss of pipes under surcharged flow, is considered as one of the major causes of inundation in urban area. Therefore, it is important to analyze the head losses at manholes, especially in case of surcharged flow. The stream characteristics were analyzed and head loss coefficients were estimated by using the computational fluid dynamics(CFD) model, FLUENT 6.3, at surcharged square manhole in this study. The CFD model was carefully assessed by comparing simulated results with the experimental ones. The study results indicate that there was good agreement between simulation model and experiment. The CFD model was proved to be capable of estimating the head loss coefficients at surcharged manholes. The head loss coefficients with variation of the ratio of manhole width(B) to inflow pipe diameter(d) and variation of the drop height at surcharged square manhole with a straight-path through were calculated using FLUENT 6.3. As the ratio of B/d increases, head loss coefficient increases. The depth and head loss coefficient at manhole were gradually increased when the drop height was more than 5cm. Therefore, the CFD model(Fluent 6.3) might be used as a tool to simulate the water depth, energy losses, and velocity distribution at surcharged square manhole.

90도 각도를 갖는 분기수로에서 모형실험결과를 이용한 손실계수 경험식 산정

박인환,성호제,김형준,이동섭 대한토목학회 2017 대한토목학회논문집 Vol.37 No.6

본 연구에서는 분기수로에서 발생되는 에너지손실을 계산하기 위한 손실계수의 경험식을 산정하기 위해 수리모형실험을 수행했다. 수리모형은 유입수로와 90도의 각도를 갖는 두 유출수로로 구성되어 있으며, 유입수로과 유출수로에서 압력수두와 속도수두를 측정하여 분기수로에서 발생되는 에너지손실을 분석했다. 각 측선에서 동수경사선의 변화를 비교한 결과, 수로의 분기점에서 동수경사선이 급격히 하강하여 에너지손실이 분기점에서 발생되었으며, 유량비의 증가에 따라 속도수두의 감소폭이 증가했다. 유량비와 Froude수가 증가함에 따라 유출량이 더 큰 수로에서 수두손실량이 지수적으로 증가하는 결과를 보였으며, 손실계수 또한 증가했다. 반면에, 유출량이 작은 수로에서는 유량비와 Froude수의 증가에 따라 손실계수가 감소하는 결과가 나타났다. 손실계수 계산결과를 이용하여 두 유출수로에서 손실계수 경험식을 제안하였으며, 경험식의 계산오차가 각각 3.91%, 5.19%로 나타났다. 그리고 두 경험식을 이용하여 계산한 총 손실계수를 실험결과와 비교하여 3.62%의 오차가 발생했다. In this study, hydraulic experimental studies were conducted to estimate the empirical formulas of loss coefficient, which is necessary to calculate the energy loss occurred in the dividing channel junction of sewer system. The experimental apparatus was consisted of two outflow conduit with a 90° angle to the inlet conduit, and the pressure and velocity heads are measured to analyze the energy losses inthe branch. The measurements of the hydraulic grade line show that the hydraulic grade line was steeply descended at the dividing point due to the head loss, and the decreasing amount of velocity head increased with the increase of flowrate ratio. The head loss exponentially increased in the outlet with larger runoff as the increase of flowrate ratio and Froude number, and the head loss coefficientalso increased. On the other hands, the head loss coefficients decreased in the outlet with smaller runoff as the increase of the flowrate ratio and Froude number. Using the experimental results, the empirical formulas of loss coefficient was suggested for each outlet, and the error of empirical formula was 3.91 and 5.19%, respectively. Furthermore, the total head loss coefficient calculated by the two empirical formulas was compared with the experimental results, and the error was 3.62%.

Development of head loss coefficient formula at surcharged four-way combining square manhole with variation of inlet flow

Jo, Jun Beom,Kim, Jung Soo,Yoon, Sei Eui 한국수자원학회 2017 한국수자원학회논문집 Vol.50 No.12

도시유역의 중·하류부에 주로 설치되는 4방향 합류맨홀에서 과부하 흐름에 의한 에너지 손실은 도심지 침수피해를 가중시키는 주요 원인이다. 과부하 4방향 합류맨홀에는 유입관의 유입조건에 따라 흐름 양상이 크게 변화되며, 중간맨홀 뿐만 아니라 3방향(T형) 합류맨홀의 흐름조건을 구성한다. 그러므로 유입관의 유입유량 변화에 따른 과부하 4방향 합류맨홀의 에너지 손실 변화 분석 및 손실계수 산정이 필요하다. 본 연구에서는 하수도시설기준을 준용하여 맨홀직경 및 관경을 1/5로 축소 한 수리실험 장치를 제작하였다. 과부하 사각형 4방향 합류맨홀에서 유입관의 유입유 량비 변화에 따른 손실계수를 산정하기 위하여 유입관(주 유입관 및 양측면 유입관)의 유입유량비를 10% 간격으로 변화시켜 다양한 유량조건(40 case)을 선정하였다. 실험 결과 중간맨홀에서 0.40의 가장 낮은 손실계수가, 90° 접합맨홀에서 1.58의 가장 높은 손실계수가 산정되었다. 또한 합류맨홀(T형, 4방향)의 경우 측면 유입유량이 한쪽으로 편향될수록 보다 큰 손실계수를 나타냈다. 유입관의 유입유량 조건 변화에 따른 손실계수를 산정하여 손실계수 범위도를 작도하였으며, 과부하 사각형 4방향 합류맨홀에서 모든 흐름조건을 고려할 수 있는 손실계수 산정식을 제시하였다. 제시된 산정식은 유입관의 유입유량이 변화하는 배수시스템의 설계 및 검증에 적용이 가능할 것으로 판단된다. The energy losses due to surcharged flow at four-way combining manhole, which is mainly installed in the downstream of urban sewer system, is the main cause of inundation in urban area. Surcharged four-way combining manholes form various flow configuration such as straight through, T-type, and four-way manholes depending on variation of inflow discharge in inlet pipes. Therefore, it is necessary to analyze change of energy loss and estimate head loss coefficients at surcharged four-way combining manhole with variation of inflow discharge ratio. The hydraulic experimental apparatus which can change inflow ratios were installed to analyze the flow characteristics at four-way combining manhole. In this study, to calculate the head loss coefficient according to change of the inflow discharge ratios at the surcharged four-way combining square manhole, the discharge conditions of 40 cases which the inflow ratios of each inlet pipe were changed by 10% interval was selected. The head loss coefficient at surcharged square manhole showed the lowest value of 0.40 at the straight manhole and the highest value of 1.58 at the 90° junction manhole. In the combining manholes (T-type and four-way), the head loss coefficients were calculated more higher as the lateral flow rate was biased. The contour map of head loss coefficient range was constructed by using the estimated head loss coefficients and the empirical formula of head loss coefficients was derived to consider the variation of inflow discharge ratios at the surcharged square manhole. The empirical formula could be applied to the design and assessment of the urban drainage system.

도시침수해석을 위한 과부하 맨홀의 손실계수 적용성 분석

김채린,김정수,윤세의 대한토목학회 2018 대한토목학회논문집 Vol.38 No.3

The XP-SWMM model, widely used for inundation analysis of urban watersheds, underestimated the inundation area (range) because the manhole was regarded as a node and the influence of the local loss occurring in the surcharged manhole can not be considered. Therefore, it is necessary to analyze the applicability of the head loss coefficients considering the local loss in the surcharged manholes in inundation analysis using XP-SWMM. The Dorim 1 drainage section of the Dorim-river watershed, where frequent domestic flood damage occurred, was selected as the study watershed. The head loss coefficients of the surcharged manholes estimated from the previous experimental studies were applied to the inundation analysis, and the changes of the inundation area with and without the application of the head loss coefficients with manhole types were compared and analyzed. As a result of inundation simulation with the application of head loss coefficients, the matching rates were increased by 17% in comparison with the without application of them. In addition, the simulated inundation area applied only the head loss coefficients of straight path manholes and applied up to the head loss coefficients of combining manholes (90° bend, 3-way, and 4-way) were similar. Therefore, in order to accurately simulate the storm drain system in urban areas, it could be to carry out two-dimensional inundation analysis considering the head loss coefficients at the surcharged manholes. It was expected that the study results will be utilized as basic data for establishing the identification of theinundation risk area. 도시유역의 침수해석에 널리 사용되는 XP-SWMM 모형은 맨홀을 하나의 절점(node)으로 간주하여 과부하 맨홀에서 발생하는 국부 손실의 영향을 고려하지 못하기 때문에 침수 면적(범위)을 과소 산정한다. 그러므로 XP-SWMM을 이용한 침수해석 시 과부하 맨홀에서의 국부손실을 고려한 손실계수의 적용성 분석이 필요한 실정이다. 본 연구에서는 내수 침수피해가 빈번히 발생하는 도림천 유역의 도림1 배수분구를 활용하여 맨홀 형태 및 손실계수 적용 유무에 따른 침수면적의 변화를 비교·분석하였다. 침수모의 결과, 손실계수를 고려한 경우가 고려하지 않은 경우 보다 실제 침수면적과의 일치율이 약 17% 증가하였다. 또한 중간맨홀 및 합류맨홀(90°접합, 3방향 및 4방향 접합 맨홀)에 따른 각각의 손실계수를 적용하여 침수 해석한 결과 중간맨홀의 손실계수만을 적용한 것과 유사한 결과가 도출되었다. 그러므로 도시지역의 침수지역을 정확하게 모의하기 위해서는 과부하 맨홀에서의 손실계수를 고려한 2차원 침수해석을 수행하여야 할 것으로 판단된다. 본 연구의 연구결과는 도시지역의 침수 위험지역을 파악하기 위한 기초적인 자료로 활용이 가능할 것으로 판단된다.