An experimental study for estimation of head loss coefficients at surcharged four-way combining manholes

Taek Hee Ryu; Jung Soo Kim; Sei Eui Yoon

doi:10.3741/JKWRA.2016.49.12.1015

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An experimental study for estimation of head loss coefficients at surcharged four-way combining manholes 과부하 4방향 합류맨홀에서의 손실계수 산정을 위한 실험 연구

31 December 2016. pp. 1015-1025

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Abstract

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, Q_lat) were varied from 0 to 4.8ℓ/sec and 24 combinations were tested in total. The flow ratios Q_lat/Q_out were varied from 0 to 1 for a total flow Q_out (Q_out=Qm+2Q_lat) 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 Q_lat/Q_out 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 (Q_lat/Q_out) were suggested in this paper.

Keywords

Four-Way Combining Manholes

Head Loss Coefficient

Surcharged Flow

Urban Sewer System

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(Q_out)에 대한 측면유입유량(Q_lat)의 비(Q_lat/Q_out) 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.

키워드

4방향 합류맨홀

손실계수

과부하 흐름

도시배수시스템

References

References

Arao, S., and Kusuda, T. (1998). “Manhole profiles for energy loss reduction.” Proceedings of HydraStorm 98, Third International Conference on Stormwater Management, pp. 235-240.

Archer, B., Bettes, F., and Cloyer, P. J. (1978). “Head losses and air entrainment at surcharged manhole.” Hydraulics Research Station, Report. No. IT185.

Choi, W. S., and Song, H. M. (2002). “A study on the hydraulic characteristics of sewer manhole.” Proceeding of Korean Society on Water Environment Conference 2002, Korean Society on Water Environment, pp. 13-16 (in Korean).

Hager, H. W. (2005). “Supercritical flow in sewer manholes.” Journal of Hydraulic Research, IAHR, Vol. 43, No. 6, pp. 660-667.10.1080/00221680509500385

Howarth, D. A., and Saul, A. J. (1984). “Energy loss coefficient at manholes.” Urban Storm Drainage, Proceeding 3rd, pp. 127-136.

Kim, J. S. (2010). “An experimental study for flow improvement at surcharged manholes.” Doctoral Dissertation of Kyonggi University (in Korean).

Kim, J. S., Song, J. I., and Yoon, S. E. (2008a). “An experimental study for estimation of head loss coefficients at surcharged circular manhole.” Journal of Korean Water Resources Association, Vol. 41, No. 3, pp. 305-314 (in Korean).10.3741/JKWRA.2008.41.3.305

Kim, J. S., Song, J. I., and Yoon, S. E. (2008b). “An experimental study for drainage capacity increment at surcharged square manholes.” Journal of Korean Society of Water and Wastewater, Vol. 22, No. 6, pp. 619-625 (in Korean).

Kim, J. S., Song, J. I., and Yoon, S. E. (2009). “An experimental study for drainage capacity increment at surcharged manholes with a 90° bend.” Journal of Korean Society of Water and Wastewater, Vol. 23, No. 4, pp. 447-458 (in Korean).

Lindvall, G. (1984). “Head loss at surcharged manholes with a main pipe and a 90° lateral.” Proceeding of 3rd International Conference on Urban Storm Drainage, pp. 137-146.

Marsalek, J., and Greek, B. J. (1988). “Head losses at manholes with a 90° bend.” Canadian Journal of Civil Engineering, Vol. 15, No. 5, pp. 851-858.10.1139/l88-110

Merlein, J. (2000). “Flow in submerged sewers with manholes.” Urban Watar, Vol. 2, No. 3, pp. 251-255.10.1016/s1462-0758(00)00063-7

Ministry of environment (2011). Design Criteria of Sewerage.

Sangster, W. M., Wood, H. W., Smerden, E. T., and Bossy, H. G. (1958). “Pressure changes at storm drain junction.” Bulletin No. 41, Engineering Experiment Station, Univ. of Missouri, Columbia.

Sangster, W. M., Wood, H. W., Smerden, E. T., and Bossy, H. G. (1959). “Pressure changes at open junction in conduits.” ASCE Journal of the Hydraulics Division, 85(HY6), pp. 13-41.

Wang, K. H., Cleveland, T. G., Towsley, C., and Umrigar, D. (1998). “Head loss at manholes in surcharged sewer systems.” Journal of the American Water Resource Association, AWRA, Vol. 34, No. 6, pp. 1391-1400.10.1111/j.1752-1688.1998.tb05439.x

Zhao, C. H., Zhu, D. Z., and Rajarattnam, N. (2006). “Experimental study of surcharged flow at combining sewer junction.” Journal of hydraulic Engineering, Vol. 132, No. 12, pp. 1259-1271.10.1061/(ASCE)0733-9429(2006)132:12(1259)

Information

Publisher :KOREA WATER RESOURECES ASSOCIATION
Publisher(Ko) :한국수자원학회
Journal Title :Journal of Korea Water Resources Association
Journal Title(Ko) :한국수자원학회 논문집
Volume : 49
No :12
Pages :1015-1025
Received Date : 2016-08-31
Revised Date : 2016-11-02
Accepted Date : 2016-11-18
DOI :https://doi.org/10.3741/JKWRA.2016.49.12.1015

Journal of Korea Water Resources Association ISSN:2799-8746(Print) 2799-8754(Online) 한국수자원학회 논문집

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