Investigation of Non Newtonian fluid effects in unsteady flow of pipe system

Authors

Abstract

Sudden change in discharge brings about significant pressure oscillations in a piping system which is known as waterhammer. Unsteady flow of a non-Newtonian fluid due to instantaneous valve closure is studied. The Cross model is used to model non-Newtonian effects. Firstly, the appropriate governing equations are derived and then, they are solved by a numerical approach. A fourth-order Runge Kutta scheme is used for time integration and a central difference scheme is employed for spatial derivatives discretization. To verify the proposed mathematical model and numerical solution, a comparison with corresponding experimental results are made. The results reveal a remarkable deviation in pressure history and velocity profile with respect to conventional waterhammer models in Newtonian fluids. The significance of the fluid behavior is manifested in drag reduction and line packing effect observed in the pressure history results. A detailed discussion regarding the fluid viscosity and its shear-stress diagrams are also included.

Keywords

Main Subjects


[1] Pinho, F.T., (2003) A GNF framework for turbulent flow models of drag reducing fluids and proposal for a k–ε type closure. J. Non-Newtonian Fluid Mech., 114(2–3): p. 149-184.
[2] Cruz, D.O.A. and F.T. Pinho, (2003) Turbulent pipe flow predictions with a low Reynolds number k–ε model for drag reducing fluids. J. Non-Newtonian Fluid Mech., 114(2–3): p. 109-148.
[3] Pinho, F.T. and J.H. Whitelaw, (1990) Flow of non-newtonian fluids in a pipe. J. Non-Newtonian Fluid Mech., 34(2): p. 129-144.
[4] Moyers-Gonzalez, M.A. and R.G. Owens, (2008) A non-homogeneous constitutive model for human blood: Part II. Asymptotic solution for large Péclet numbers. J. Non-Newtonian Fluid Mech., 155(3): p. 146-160.
[5] Moyers-Gonzalez, M.A., R.G. Owens, and J. Fang, (2008) A non-homogeneous constitutive model for human blood: Part III. Oscillatory flow. J. Non-Newtonian Fluid Mech., 155(3): p. 161-173.
[6] Moyers-Gonzalez, M.A., R.G. Owens, and J. Fang, (2009) On the high frequency oscillatory tube flow of healthy human blood. J. Non-Newtonian Fluid Mech., 163(1–3): p. 45-61.
[7] Vardy, A.E. and J.M.B. Brown, (2011) Laminar pipe flow with time-dependent viscosity. J HYDROINFORM, 13(4): p. 729–740.
[8] Riasi, A., A. Nourbakhsh, and M. Raisee, (2009) Unsteady Velocity Profiles in Laminar and Turbulent Water Hammer Flows. J. Fluids Eng, 131(12): p. 121202-121202.
[9] Toms, B.A. (1948) Some Observation on the Flow of Linear Polymer Solutions Through Straight Tubes at Large {R}eynolds Numbers. in Proc. 1st Intl. Congr. on Rheology. 1948.
[10] Oliveira, G.M., C.O.R. Negrão, and A.T. Franco, (2012) Pressure transmission in Bingham fluids compressed within a closed pipe. J. Non-Newtonian Fluid Mech., 169–170(0): p. 121-125.
[11] Lai, W.M., et al., (2010) Introduction to continuum mechanics. 4th ed Amsterdam ; Boston: Butterworth-Heinemann/Elsevier.
[12] Bird, R.B., R.C. Armstrong, and O. Hassager, (1987) Dynamics of polymeric liquids. 2 ed. Vol. 1.
[13] Tijsseling, A.S., (1993) Fluid – structure interaction in case of waterhammer with cavitation in Civil Engineering Department1993, Delft University of Technology: Netherlands.
[14] Ghidaoui, M.S., et al., (2005) A Review of Water Hammer Theory and Practice. Appl. Mech. Rev., 58(1): p. 49-76.
[15] Wylie, E.B., V.L.A. STREETER, and L. Suo, (1993) Fluid Transients in Systems: Prentice Hall PTR.
[16] Chhabra, R.P. and J.F. Richardson, (2011) Non-Newtonian Flow and Applied Rheology: Engineering Applications. 2nd ed: Elsevier Science.
[17] Oliveira, P.J. and F.T. Pinho, (1998) A qualitative assessment of the role of a viscosity depending on the third invariant of the rate-of-deformation tensor upon turbulent non-Newtonian flow. J. Non-Newtonian Fluid Mech., 78(1): p. 1-25.
[18] (1981) Numerical solution of the Euler equations by finite volume methods using Runge Kutta time stepping schemes. in AIAA, Fluid and Plasma Dynamics Conference, 14th, Palo Alto, CA, June 23-25, 1981. 15 p. 1981.
[19] Wahba, E.M., (2006) Runge–Kutta time-stepping schemes with TVD central differencing for the water hammer equations. Int. J. Numer. Meth. Fluids, 52(5): p. 571-590.
[20] Holmboe, E.L. and W.T. Rouleau, (1967) The Effect of Viscous Shear on Transients in Liquid Lines. J BASIC ENG., 89(1): p. 174-180.