Swirling Flow of a Viscoelastic Fluid in a Cylindrical Casing

2005 ◽  
Vol 128 (1) ◽  
pp. 88-94 ◽  
Author(s):  
Motoyuki Itoh ◽  
Masahiro Suzuki ◽  
Takahiro Moroi
Keyword(s):  
Viscoelastic Fluid ◽  
Power Law ◽  
Velocity Component ◽  
Swirling Flow ◽  
Rotating Disk ◽  
Circumferential Velocity ◽  
Working Fluid ◽  
Velocity Measurements ◽  
Aspect Ratios ◽  
Cylindrical Casing

The swirling flow of a viscoelastic fluid in a cylindrical casing is investigated experimentally, using aqueous solutions of 0.05–1.0wt.% polyacrylamide as the working fluid. The velocity measurements are made using laser Doppler anemometer. The aspect ratios H∕R (H: axial length of cylindrical casing; R: radius of rotating disk) investigated are 2.0, 1.0, and 0.3. The Reynolds numbers Re0 based on the zero shear viscosity and the disk-tip velocity are between 0.36 and 50. The velocity measurements are mainly conducted for the circumferential velocity component. The experimental velocity data are compared to the velocity profiles obtained by numerical simulations using Giesekus model and power-law model. It is revealed that at any aspect ratios tested the dimensionless circumferential velocity component Vθ′ decreases with increasing Weissenberg number We. Both the Giesekus and power-law models could predict the retardation of circumferential velocity fairly well at small We. The extent of the inverse flow region, where the fluid rotates in the direction opposite to the rotating disk, is clarified in detail.

Swirling Flow of Viscoelastic Fluid in a Cylindrical Casing

2003 ◽  
Author(s):  
Motoyuki Itoh ◽  
Masahiro Suzuki ◽  
Takahiro Moroi
Keyword(s):  
Viscoelastic Fluid ◽  
Power Law ◽  
Velocity Component ◽  
Swirling Flow ◽  
Circumferential Velocity ◽  
Power Law Model ◽  
Velocity Measurements ◽  
Rotating Disc ◽  
Aspect Ratios ◽  
Cylindrical Casing

The swirling flow of viscoelastic fluid in a cylindrical casing is investigated experimentally, using aqueous solutions of 0.05–1.0 wt% polyacrylamide as the working fluid. The velocity measurements are made using laser Doppler anemometer. The aspect ratios H/R (H: axial length of cylindrical casing, R: radius of rotating disc) investigated are 2.0, 1.0 and 0.3. The Reynolds numbers Re0 based on the zero shear viscosity and the disc tip velocity are between 0.36 and 50. The velocity measurements are mainly conducted for the circumferential velocity component. The experimental velocity data are compared with the velocity profiles obtained by numerical simulations using Giesekus model and power-law model. It is revealed that at any aspect ratios tested the dimensionless circumferential velocity component Vθ’ decreases with increasing Weissenberg number We. The Giesekus model could predict this retardation of circumferential velocity fairly well at small We, but the power-law model could not. The extent of the inverse flow region where the fluid rotates in the direction opposite to the rotating disc is clarified in detail.

Effect of Diffuser Vane Solidity on Performance of a Multistage Bowl Pump

2019 ◽  
Author(s):  
Paul Cooper ◽  
Ashvin Hosangadi
Keyword(s):  
Velocity Component ◽  
Swirling Flow ◽  
Axial Direction ◽  
Circumferential Velocity ◽  
Large Field ◽  
Design Practice ◽  
Mixed Flow ◽  
Percentage Points ◽  
Specific Speed ◽  
Radical Approach

Abstract The performance of a mixed-flow three-stage pump having a stage specific speed Ns = 2630 (rpm, gpm, ft) or nq = 53 (rpm, m3/s, m) — commonly known as a “bowl” pump — was improved by nearly five (5) percentage points by substantially increasing the number of vanes in the bowl-type diffuser. analysis showed a large field of unintended swirling flow emerging from the exit of the original diffuser. The solidity of the improved diffuser was much greater than conventional design practice would indicate. Yet this was needed to eliminate separation of the radially inward diffusing flow from the vanes as they effectively guide the fluid into the axial direction, thereby enabling the following stage(s) to generate the intended head and so achieve the intended efficiency. This apparently radical approach appears to be necessary in order to overcome the tendency of the circumferential velocity component of the flow from the impeller to increase as it is transported to the smaller radii of this radial inflow diffuser configuration.

MHD Flow of Shear-Thinning Fluid over a Rotating Disk with Heat Transfer

2011 ◽  
Vol 130-134 ◽  
pp. 3599-3602
Author(s):  
Chun Ying Ming ◽  
Lian Cun Zheng ◽  
Xin Xin Zhang
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Power Law ◽  
Swirling Flow ◽  
Mhd Flow ◽  
Rotating Disk ◽  
Electrically Conducting ◽  
Flow And Heat Transfer ◽  
Power Law Index ◽  
Shear Thinning Fluid

This paper studied the Magneto hydrodynamic (MHD) flow and heat transfer of an electrically conducting non-Newtonian fluid over a rotating disk in the presence of a uniform magnetic field. The steady, laminar and axial-symmetric flow is driven solely by the rotating disk, and the incompressible fluid obeys the inelastic Ostwald de-Waele power-law model. The governing differential equations were reduced to a set of ordinary differential equations by utilizing the generalized Karman similarity transformation. The nonlinear two-point boundary value problem is solved by multi-shooting method. Numerical results show that the magnetic parameter and the power-law index have significant effects on the swirling flow and heat transfer.

The Effect of Suction on the Swirling Flow of Non-Newtonian Fluid

2014 ◽  
Vol 501-504 ◽  
pp. 2081-2084
Author(s):  
Chun Ying Ming ◽  
Lian Cun Zheng ◽  
Xin Xin Zhang
Keyword(s):  
Differential Equations ◽  
Power Law ◽  
Shooting Method ◽  
Numerical Solutions ◽  
Swirling Flow ◽  
Similarity Transformation ◽  
Rotating Disk ◽  
Shear Thinning Fluids ◽  
Suction Or Injection ◽  
Power Law Index

The flow of an incompressible viscous power-law fluid over an infinite rotating disk with uniform suction or injection is studied. The governing differential equations, which are partial and coupled, are simplified to a set of ordinary differential equations by generalized Karman similarity transformation. Numerical solutions of the non-linear two point boundary value problem are obtained by multi-shooting method. The effects of the power-law index and the porous parameter on the velocity fields are discussed for shear thinning fluids.

scholarly journals Analytical Velocity Study in a Conical Diffuser with Screw Tape Inserts

2018 ◽  
Vol 153 ◽  
pp. 06003
Author(s):  
Ehan Sabah Shukri
Keyword(s):  
Reynolds Number ◽  
Numerical Analysis ◽  
Boundary Conditions ◽  
Velocity Distribution ◽  
Numerical Simulations ◽  
Swirling Flow ◽  
Working Fluid ◽  
Aspect Ratios ◽  
Conical Diffuser ◽  
Better Than

A study is made to enhance the rate of velocity distribution in a conical diffuser. In this work, a numerical analysis on screw tape inserts in a conical diffuser is presented. In the numerical simulations, the swirling flow was introduced by using rectangular screw tape placed inside the inner test wall of the conical diffuser. Screw tape with different aspect ratios (AS) 2.5, 3.5, 4.5, 6.5 and 7.5 was analysed. The simulations were carried out with constant inlet condition considering the flow turbulent and incompressible with inlet Reynolds number 3.2 × 105. The simulations were performed using air as a working fluid. The results obtained from the conical diffuser with screw tape inserts are compared with those without screw tape (plain conical diffuser). On the basis of the same inlet boundary conditions for the screw tape in the conical diffuser and the plain conical diffuser, it was found that the velocity distribution performance of screw tape inserts with different AS is better than plain conical diffuser. It is also observed that the screw tape with AS 3.5 offered the best velocity distribution rate.

scholarly journals Sealing Flow Requirements for a Rotating Disk With External Swirling Flow

1994 ◽  
Author(s):  
Michael G. Izenson ◽  
Waiter L. Swift ◽  
Ronald H. Aungier
Keyword(s):  
Swirling Flow ◽  
Tangential Velocity ◽  
Rotating Disk ◽  
External Flow ◽  
Turbine Disk ◽  
Working Fluid ◽  
Published Data ◽  
Rotating Disks ◽  
Hot Gas ◽  
Process Gas

Experiments have been performed to investigate the sealing flow requirements for a shrouded, rotating disk with external swirling flow. In some gas turbine applications, it is desirable to provide sealing flow to prevent ingress of process gas into the cavity between the turbine disk and its stator. The tangential or swirl component in flow leaving the nozzles can significantly affect the amount of flow required to seal the turbine disk. The experimental flow model used water as a working fluid and was hydrodynamically scaled to match conditions typical of hot gas expander turbines used for energy recovery in the petrochemical industry. Flow in the seal gap was observed using a stream of dye injected on the stator face near the periphery. Differential pressures were measured on the stator face and related to the observed direction of flow on the stator face. The pressures and sealing flows were normalized by the disk and gap geometry and the applied flow conditions, then compared to published data for shrouded, rotating disks with no applied, external flow. For tests where the external tangential velocity was roughly equal to twice the rim speed of the disk, sealing flow requirements were found to be 1.5 to 2.0 times greater than for a disk without the applied, external flow.

scholarly journals Impact of autocatalytic chemical reaction in an Ostwald-de-Waele nanofluid flow past a rotating disk with heterogeneous catalysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bai Yu ◽  
Muhammad Ramzan ◽  
Saima Riasat ◽  
Seifedine Kadry ◽  
Yu-Ming Chu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Differential Equations ◽  
Chemical Reaction ◽  
Power Law ◽  
Variable Thickness ◽  
Rotating Disk ◽  
Thermal Profile ◽  
Nanofluid Flow ◽  
Power Law Index

AbstractThe nanofluids owing to their alluring attributes like enhanced thermal conductivity and better heat transfer characteristics have a vast variety of applications ranging from space technology to nuclear reactors etc. The present study highlights the Ostwald-de-Waele nanofluid flow past a rotating disk of variable thickness in a porous medium with a melting heat transfer phenomenon. The surface catalyzed reaction is added to the homogeneous-heterogeneous reaction that triggers the rate of the chemical reaction. The added feature of the variable thermal conductivity and the viscosity instead of their constant values also boosts the novelty of the undertaken problem. The modeled problem is erected in the form of a system of partial differential equations. Engaging similarity transformation, the set of ordinary differential equations are obtained. The coupled equations are numerically solved by using the bvp4c built-in MATLAB function. The drag coefficient and Nusselt number are plotted for arising parameters. The results revealed that increasing surface catalyzed parameter causes a decline in thermal profile more efficiently. Further, the power-law index is more influential than the variable thickness disk index. The numerical results show that variations in dimensionless thickness coefficient do not make any effect. However, increasing power-law index causing an upsurge in radial, axial, tangential, velocities, and thermal profile.

Velocity measurements made with a laser dopplermeter on the turbulent pipe flow of a dilute polymer solution

1972 ◽  
Vol 51 (4) ◽  
pp. 673-685 ◽  
Author(s):  
M. J. Rudd
Keyword(s):  
Polymer Solution ◽  
Velocity Component ◽  
Pipe Flow ◽  
Viscous Sublayer ◽  
Turbulent Pipe Flow ◽  
Velocity Measurements ◽  
Velocity Fluctuations ◽  
Conventional Models ◽  
Drag Reducing Polymer ◽  
Spanwise Velocity

This paper presents some new measurements which have been made on a drag-reducing polymer solution in pipe flow. A novel type of laser dopplermeter, which has been developed by the author, is briefly described and the measurements which have been obtained are given. These results and their implications are then discussed in terms of conventional models for turbulent flow in a pipe. These suggest that the polymer has very little effect upon the turbulent core of the flow, but thickens and stabilizes the viscous sublayer. The turbulent intensity inside the sublayer is unchanged but, owing to its thickening, the velocity fluctuations just outside are greater. There is not a general suppression of turbulence within the sublayer although well inside the sublayer the spanwise velocity component is found to be reduced.

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