# Waterwheel shaped turbine inside a pipe simulation problem

 Register Blogs Members List Search Today's Posts Mark Forums Read December 1, 2014, 10:57 Waterwheel shaped turbine inside a pipe simulation problem #1 New Member   Mohaimin Shahed Join Date: Nov 2014 Posts: 2 Rep Power: 0 Hello Everyone, I am very new to CFD and I have carried out a simulation for a undershot waterwheel placed inside a pipeline. Currently I have used a rigid body for my waterwheel, and have two domains, one for the region surrounding the rigid body and another for the remainder of the pipe. I have specified my rotor domain as a subdomain with the option of rigid body solution and have also used a wall boundary condition for the wheel walls with the option of rigid body solution. To calculate power, I use different external torques (on the opposite direction to rotation) on the rigid body and see what my final angular velocity and try to find the optimum torque for which I have max power (Torque times angular velocity). I have attached several images to help explain what I have done. I would greatly appreciate any suggestions to help improve the accuracy of my simulation since I am not sure I am doing it right. Best Regards, Mohaimin LIBRARY: COORDINATE FRAME DEFINITIONS:PlotData.png BackView.JPG IsoView.JPG Setupview.jpg WireframeView.JPG COORDINATE FRAME: Coord 1 Axis 3 Point = 0.0[m],0.0[m],1.0[m] Coord Frame Type = Cartesian Option = Axis Points Origin Point = 0.0[m],0.0[m],0.0[m] Plane 13 Point = 1.0[m],0.0[m],0.0[m] Reference Coord Frame = Coord 0 END END MATERIAL: Crude Oil Material Group = User Option = Pure Substance PROPERTIES: Option = General Material EQUATION OF STATE: Density = 870 [kg m^-3] Molar Mass = 154 [kg kmol^-1] Option = Value END DYNAMIC VISCOSITY: Dynamic Viscosity = 0.0105 [Pa s] Option = Value END END END END FLOW: Flow Analysis 1 SOLUTION UNITS: Angle Units = [rad] Length Units = [m] Mass Units = [kg] Solid Angle Units = [sr] Temperature Units = [K] Time Units = [s] END ANALYSIS TYPE: Option = Transient EXTERNAL SOLVER COUPLING: Option = None END INITIAL TIME: Option = Automatic with Value Time = 0 [s] END TIME DURATION: Option = Total Time Total Time = 3 [s] END TIME STEPS: Option = Timesteps Timesteps = 0.025 [s] END END DOMAIN: Rotor Coord Frame = Coord 1 Domain Type = Fluid Location = B763 BOUNDARY: Default Fluid Fluid Interface Side 1 Boundary Type = INTERFACE Location = F583.763 BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = Conservative Interface Flux END MESH MOTION: Option = Stationary END TURBULENCE: Option = Conservative Interface Flux END END END BOUNDARY: Domain Interface 1 Side 1 Boundary Type = INTERFACE Location = RotorInterface1 BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = Conservative Interface Flux END MESH MOTION: Option = Stationary END TURBULENCE: Option = Conservative Interface Flux END END END BOUNDARY: RotorWall Boundary Type = WALL Location = RotorWall BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = No Slip Wall Wall Velocity Relative To = Mesh Motion END MESH MOTION: Option = Rigid Body Solution Rigid Body = Rigid Body 1 END WALL ROUGHNESS: Option = Smooth Wall END END END BOUNDARY: Symmetry Boundary Type = SYMMETRY Location = F586.763 BOUNDARY CONDITIONS: MESH MOTION: Option = Unspecified END END END DOMAIN MODELS: BUOYANCY MODEL: Option = Non Buoyant END DOMAIN MOTION: Option = Stationary END MESH DEFORMATION: Displacement Relative To = Previous Mesh Option = Regions of Motion Specified MESH MOTION MODEL: Option = Displacement Diffusion MESH STIFFNESS: Option = Increase near Small Volumes Stiffness Model Exponent = 2.0 REFERENCE VOLUME: Option = Mean Control Volume END END END END REFERENCE PRESSURE: Reference Pressure = 1 [atm] END END FLUID DEFINITION: Fluid 1 Material = Crude Oil Option = Material Library MORPHOLOGY: Option = Continuous Fluid END END FLUID MODELS: COMBUSTION MODEL: Option = None END HEAT TRANSFER MODEL: Option = None END THERMAL RADIATION MODEL: Option = None END TURBULENCE MODEL: Option = k epsilon END TURBULENT WALL FUNCTIONS: Option = Scalable END END INITIALISATION: Option = Automatic INITIAL CONDITIONS: Velocity Type = Cartesian CARTESIAN VELOCITY COMPONENTS: Option = Automatic with Value U = 0 [m s^-1] V = 0 [m s^-1] W = 0 [m s^-1] END STATIC PRESSURE: Option = Automatic with Value Relative Pressure = 0 [Pa] END TURBULENCE INITIAL CONDITIONS: Option = Medium Intensity and Eddy Viscosity Ratio END END END SUBDOMAIN: Subdomain 1 Coord Frame = Coord 1 Location = B763 MESH MOTION: Option = Rigid Body Solution Rigid Body = Rigid Body 1 END END END DOMAIN: Stator Coord Frame = Coord 1 Domain Type = Fluid Location = B640 BOUNDARY: Default Fluid Fluid Interface Side 2 Boundary Type = INTERFACE Location = F493.640 BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = Conservative Interface Flux END TURBULENCE: Option = Conservative Interface Flux END END END BOUNDARY: Domain Interface 1 Side 2 Boundary Type = INTERFACE Location = StatorInterface1 BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = Conservative Interface Flux END TURBULENCE: Option = Conservative Interface Flux END END END BOUNDARY: Inlet Boundary Type = INLET Location = F486.640 BOUNDARY CONDITIONS: FLOW DIRECTION: Option = Normal to Boundary Condition END FLOW REGIME: Option = Subsonic END MASS AND MOMENTUM: Mass Flow Rate = 1100 [kg s^-1] Option = Mass Flow Rate END TURBULENCE: Option = Medium Intensity and Eddy Viscosity Ratio END END END BOUNDARY: Outlet Boundary Type = OUTLET Location = F485.640 BOUNDARY CONDITIONS: FLOW REGIME: Option = Subsonic END MASS AND MOMENTUM: Mass Flow Rate = 1100 [kg s^-1] Option = Mass Flow Rate END END END BOUNDARY: Symmetry2 Boundary Type = SYMMETRY Location = F491.640 END BOUNDARY: Wall Boundary Type = WALL Location = Wall BOUNDARY CONDITIONS: MASS AND MOMENTUM: Option = No Slip Wall END WALL ROUGHNESS: Option = Smooth Wall END END END DOMAIN MODELS: BUOYANCY MODEL: Option = Non Buoyant END DOMAIN MOTION: Option = Stationary END MESH DEFORMATION: Option = None END REFERENCE PRESSURE: Reference Pressure = 1 [atm] END END FLUID DEFINITION: Fluid 1 Material = Crude Oil Option = Material Library MORPHOLOGY: Option = Continuous Fluid END END FLUID MODELS: COMBUSTION MODEL: Option = None END HEAT TRANSFER MODEL: Option = None END THERMAL RADIATION MODEL: Option = None END TURBULENCE MODEL: Option = k epsilon END TURBULENT WALL FUNCTIONS: Option = Scalable END END INITIALISATION: Option = Automatic INITIAL CONDITIONS: Velocity Type = Cartesian CARTESIAN VELOCITY COMPONENTS: Option = Automatic with Value U = 0 [m s^-1] V = 0 [m s^-1] W = 0 [m s^-1] END STATIC PRESSURE: Option = Automatic with Value Relative Pressure = 0 [Pa] END TURBULENCE INITIAL CONDITIONS: Option = Medium Intensity and Eddy Viscosity Ratio END END END END DOMAIN INTERFACE: Default Fluid Fluid Interface Boundary List1 = Default Fluid Fluid Interface Side 1 Boundary List2 = Default Fluid Fluid Interface Side 2 Interface Type = Fluid Fluid INTERFACE MODELS: Option = General Connection FRAME CHANGE: Option = None END MASS AND MOMENTUM: Option = Conservative Interface Flux MOMENTUM INTERFACE MODEL: Option = None END END PITCH CHANGE: Option = None END END MESH CONNECTION: Option = GGI END END DOMAIN INTERFACE: Domain Interface 1 Boundary List1 = Domain Interface 1 Side 1 Boundary List2 = Domain Interface 1 Side 2 Interface Type = Fluid Fluid INTERFACE MODELS: Option = General Connection FRAME CHANGE: Option = None END MASS AND MOMENTUM: Option = Conservative Interface Flux MOMENTUM INTERFACE MODEL: Option = None END END PITCH CHANGE: Option = None END END MESH CONNECTION: Option = GGI END END OUTPUT CONTROL: MONITOR OBJECTS: MONITOR BALANCES: Option = Full END MONITOR FORCES: Option = Full END MONITOR PARTICLES: Option = Full END MONITOR POINT: Monitor Point 1 Coord Frame = Coord 1 Expression Value = torque_z@RotorWall Option = Expression END MONITOR RESIDUALS: Option = Full END MONITOR TOTALS: Option = Full END END RESULTS: File Compression Level = Default Option = Standard END TRANSIENT RESULTS: Transient Results 1 File Compression Level = Default Option = Standard OUTPUT FREQUENCY: Option = Time Interval Time Interval = 0.075 [s] END END END RIGID BODY: Rigid Body 1 Location = RotorWall Mass = 5.15 [kg] Rigid Body Coord Frame = Coord 1 DYNAMICS: DEGREES OF FREEDOM: ROTATIONAL DEGREES OF FREEDOM: Option = Z axis END TRANSLATIONAL DEGREES OF FREEDOM: Option = None END END GRAVITY: Gravity X Component = 0 [m s^-2] Gravity Y Component = -9.81 [m s^-2] Gravity Z Component = 0 [m s^-2] Option = Cartesian Components END END INITIAL CONDITIONS: ANGULAR VELOCITY: Option = Automatic with Value xValue = 0 [radian s^-1] yValue = 0 [radian s^-1] zValue = 0 [radian s^-1] END CENTRE OF MASS: Option = Automatic END LINEAR VELOCITY: Option = Automatic with Value xValue = 0 [m s^-1] yValue = 0 [m s^-1] zValue = 0 [m s^-1] END END MASS MOMENT OF INERTIA: xxValue = 0.048 [kg m^2] xyValue = 0 [kg m^2] xzValue = 0 [kg m^2] yyValue = 0.048 [kg m^2] yzValue = 0 [kg m^2] zzValue = 0.051 [kg m^2] END END SOLVER CONTROL: Turbulence Numerics = First Order ADVECTION SCHEME: Option = High Resolution END CONVERGENCE CONTROL: Maximum Number of Coefficient Loops = 10 Minimum Number of Coefficient Loops = 1 Timescale Control = Coefficient Loops END CONVERGENCE CRITERIA: Residual Target = 1.E-4 Residual Type = RMS END TRANSIENT SCHEME: Option = Second Order Backward Euler TIMESTEP INITIALISATION: Option = Automatic END END END END COMMAND FILE: Version = 15.0 Results Version = 15.0 END SIMULATION CONTROL: EXECUTION CONTROL: EXECUTABLE SELECTION: Double Precision = Off END INTERPOLATOR STEP CONTROL: Runtime Priority = Standard DOMAIN SEARCH CONTROL: Bounding Box Tolerance = 0.01 END INTERPOLATION MODEL CONTROL: Enforce Strict Name Mapping for Phases = Off Mesh Deformation Option = Automatic Particle Relocalisation Tolerance = 0.01 END MEMORY CONTROL: Memory Allocation Factor = 1.0 END END PARALLEL HOST LIBRARY: HOST DEFINITION: winserv5 Host Architecture String = winnt-amd64 Installation Root = C:\Program Files\ANSYS Inc\v%v\CFX END END PARTITIONER STEP CONTROL: Multidomain Option = Independent Partitioning Runtime Priority = Standard EXECUTABLE SELECTION: Use Large Problem Partitioner = Off END MEMORY CONTROL: Memory Allocation Factor = 1.0 END PARTITIONING TYPE: MeTiS Type = k-way Option = MeTiS Partition Size Rule = Automatic END END RUN DEFINITION: Run Mode = Full Solver Input File = No gap from turbine to wall but same dim.def END SOLVER STEP CONTROL: Runtime Priority = Standard MEMORY CONTROL: Memory Allocation Factor = 1.0 END PARALLEL ENVIRONMENT: Number of Processes = 1 Start Method = Serial END END END END   December 1, 2014, 16:11 #2 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,486 Rep Power: 140    Have you read the FAQ on accuracy? http://www.cfd-online.com/Wiki/Ansys..._inaccurate.3F   December 2, 2014, 17:38 #3 New Member   Mohaimin Shahed Join Date: Nov 2014 Posts: 2 Rep Power: 0 Hello Ghorrocks, Thanks for your reply. I had done some sensitivity analysis with regards to grid density, turbulence model and turbulence intensity. But so far I have used smooth walls for my rigid body. For some reason inflating the region around my rigid body has not changed my results much, so I am wondering if I am doing something wrong.   January 10, 2015, 11:19 #4 Member   Thomas Join Date: Dec 2014 Location: Poland Posts: 49 Rep Power: 10 Hi mshahed91 I have a problem, cause I try to simulate simply wind turbine to find angular velocity of rotor, but unfortunately it still fail. I created domain, subdomain, and rigid body to pattern from your CEL library.Probably the problem is cennected with mesh motion and setup with that. The question is: Could you send to me your file with this simulation of waterwheel? Also I can send to you my file with my wind turbine. Regards, Tomasz  Thread Tools Search this Thread Show Printable Version Email this Page Search this Thread: Advanced Search Display Modes Linear Mode Switch to Hybrid Mode Switch to Threaded Mode Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are Off Pingbacks are On Refbacks are On Forum Rules Similar Threads Thread Thread Starter Forum Replies Last Post PorscheGTIII OpenFOAM Running, Solving & CFD 1 November 3, 2013 10:54 John C. CFX 7 December 5, 2011 08:31 be_inspired FLUENT 2 March 7, 2011 23:46 Purushothama Main CFD Forum 0 November 7, 2010 20:12 ram Main CFD Forum 5 June 17, 2000 21:31

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