Modeling Air Entrainment Rate and Aeration Efficiency of Weirs Using ANN Approach

Yıl 2009, Cilt: 22 Sayı: 2, 107 - 116, 22.03.2010

Ahmet Baylar , Ozgur Kısı M. Emin Emıroglu

Öz

The concentration of dissolved oxygen is an important indicator of water quality because aquatic life lives on the dissolved oxygen in the water. A free overfall jet from a weir plunging into downstream water causes entrainment of the air bubbles if the free overfall jet velocity exceeds a certain critical value and hence aeration occurs. This paper investigates the free overfall jets from triangular sharp−crested weirs and their effect on the air entrainment rate and the aeration efficiency. The artificial neural network models, multi nonlinear and linear regression equations were obtained for the triangular sharp−crested weirs relating the air entrainment rate and the aeration efficiency to drop height, discharge, and angle in triangular sharp−crested weir. There were good agreements between the measured values and the values obtained using the artificial neural network and multi nonlinear regression models.

 

Key Words: Air entrainment rate, Aeration efficienc,; Dissolved oxygen; Weir, Neural networks.

Anahtar Kelimeler

Air entrainment rate, Aeration efficienc, , Dissolved oxygen, Weir, Neural networks

Kaynakça

• Wilhelms, S.C., Gulliver, J.S. , Parkhill, K., “Reaeration at Low-Head Hydraulic Structures”, Tech. Rep. Hl-91, US Army Engineer Waterways Experiment Station, Vicksburg, Miss, (1992). Chanson, H., “Predicting
• Downstream of Weirs”, Spillways and Waterways. Proc. Instn Civ. Engrs Wat., Marit. & Energy, , March, 20-30 (1995). Oxygen Content
• Ervine, D.A., “Air Entrainment in Hydraulic Structures: A Review”, Proc. Instn Civ. Engrs Wat., Marit. & Energy, 130, September, 142-153 (1998).
• Gulliver, J.S., Wilhelms, S.C., Parkhill, K.L., “Predictive Capabilities in Oxygen Transfer at Hydraulics Structures”, J. Hydr. Engrg., ASCE, (7): 664-671 (1998).
• Baylar, A., Bagatur, T., “Aeration Performance of Weirs”, Water SA, 26 (4): 521-526 (2000).
• Baylar, A., Bagatur, T., “Aeration Performance of Weirs”, Water Engineering & Management, Part , 148 (3): 33-36 (2001).
• Baylar, A., Bagatur, T., “Aeration Performance of Weirs”, Water Engineering & Management, Part , 148 (4): 14-16 (2001).
• Baylar, A., Bagatur, T., Tuna, A., “Aeration Performance of Triangular Notch Weirs at Recirculating System”, Water Quality Research Journal of Canada, 36 (1): 121-132. (2001).
• Baylar, A., Bagatur, T., Tuna, A., “Aeration Performance of Triangular-Notch Weirs”, Journal of the Chartered Institution of Water & Environmental Management, 15 (3): 203-206 (2001).
• Baylar, A., “Study on the Effect of Type Selection of Weir Aerators on Oxygen Transfer”, Ph.D. Thesis, Firat University, Elazig, Turkey, (In Turkish), (2002).
• Baylar, A., Emiroglu, M.E., “The Effect of Sharp- Crested Weir Shape on Air Entrainment”, Canadian Journal of Civil Engineering, 29 (3): 383 (2002).
• Baylar, A., Bagatur, T., “Experimental Studies on Air Entrainment and Oxygen Content Downstream of Sharp-Crested Weirs”, Water & Environment Journal, 20 (4): 210-216 (2006).
• Gameson, A.L.H., “Weirs and Aeration of Rivers”, Journal of the Institution of Water Engineers, 11 (5): 477-490 (1957).
• Ervine, D.A., McKeogh, E.J., Elsawy, E.M., “Effect of Turbulence Intensity on the Rate of Air Entrainment by Plunging Water Jets”, Proc. Instn Civ. Engrs., London, 69 (2): 425-445 (1980).
• Tsang, C.C., “Hydraulic and Aeration Performance of Labyrinth Weirs”, Ph.D. Thesis, University of London, London, (1987). Wormleaton, P.R., Tsang,
• Performance of Rectangular Planform Labyrinth Weirs”, J. Envir. Engrg., ASCE, 126 (5): 456-465 (2000). C.C., “Aeration
• Gameson, A.L.H., Vandyke, K.G., Ogden, C.G., “The Effect of Temperature on Aeration at Weirs”, Water & Water Engrg., 62, Nov., 489-492 (1958).
• Holler, A.G., “Reaeration of Discharge through Hydraulic Structures”, Ph.D. Thesis, University of Cincinnati, Cincinnati, Ohio, (1970).
• Gulliver, J.S., Thene, J.R., Rindels, A.J., “Indexing Gas Transfer in Self-Aerated Flows”, J. Envir. Engrg., ASCE, 116 (3): 503-523 (1990).
• Levich, V.G., “Physicochemical Hydrodynamics”, Prentice-Hall, Englewood Cliffs, N.J, (1962).
• Hinze, J.O., “Fundamentals of the Hydrodynamic Mechanism of Splitting in Dispersion Processes”, Am. Inst. of Chem. Eng., 1 (3): 289-295 (1955).
• Azbel, D., “Two Phase Flows in Chemical Engineering”, Cambridge Univ. Press, Cambridge, England, (1981).
• Lippman, R., “An Introduction to Computing with Neural Nets”, IEEE ASSP Mag., 4 (2): 4-22 (1987).
• Marquardt, D., “An Algorithm for Least Squares Estimation of Non-Linear Parameters”, J. Soc. Ind. Appl. Math., 11 (2): 431-441 (1963).
• Hagan, M.T., Menhaj, M., “Training Feedforward Networks with the Marquardt Algorithm”, IEEE Transactions on Neural Networks, 5 (6): 989-993 (1994).
• Hornik, K., Stinchcombe, M., White, H., “Multilayer Feedforward Networks are Universal Approximators”, Neural Networks, 2 (5): 359-366 (1989).