Gearbox sloshing effect

Objective:

  • To analyse the flow pattern of the fluid inside the gearbox, for two different clearances of the same geometry and each geometry flow is analyzed by two different fluids (Water and Oil) as lubricants.

Gearbox sloshing effect: 

  • Slosh refers to the movement of liquid inside another object (which is, typically, also undergoing motion), the liquid must have a free surface to constitute a slosh dynamics.
  • The dynamics of the liquid can interact with the gears in the gearbox to alter the system dynamics significantly.
  • Other examples are:

             1. Propellent slosh in spacecraft tanks and rockets (especially upper stages), and

             2. The free surface effect (cargo slosh) in ships and trucks transporting liquids (oil                     and gasoline).

             3. Liquid motion in a completely filled tank, i.e. without a free surface, as "fuel                         slosh".

User Defined Function (udf) used:
 
#include "udf.h"
 
DEFINE_CG_MOTION(right_motion, dt, vel, omega, time, dtime)
{
vel[0] = 0.0;
vel[1] = 0.0;
vel[2] = 0.0;
 
omega[0] = 0.0;
omega[1] = 0.0;
omega[2] = 2.0e2; /* [rad/s]*/
}
DEFINE_CG_MOTION(left_motion, dt, vel, omega, time, dtime)
{
vel[0] = 0.0;
vel[1] = 0.0;
vel[2] = 0.0;
 
omega[0] = 0.0;
omega[1] = 0.0;
omega[2] = -2.0e2; /* [rad/s]*/
}

Note: First install Visual C++ command prompt, Ansys workbench is opened through Visual C++ command prompt for all cases.

Case 1: GearBox with gears, engaged with small clearance (water is used as lubricant):

Geometry:

Gears engaged with small clearance(Distance between the centres of gears is 115 mm):

2D Gear:

2D Gear Mesh:

SIMULATION SETUP DETAILS:

I. SETUP PHYSICS

SOLVER

     Type --> pressure based

     velocity Formulation --> Absolute

     Time --> Transient

     2D space --> planar

     Gravity - Tick the check box

     Gravitational Acceleration 

            X (m/s2) = 0

            Y (m/s2) = -9.81

MODELS

 Viscous --> k-epsilon

 k-epsilon Model --> Reliazable

 Near-wall Treatment --> Enhanced wall treatment

 Multiphase

      Model --> volume of Fluid

      Formulation --> Implicit

MATERIALS

Create/Edit Materials

      Air: 

     Density = 1.225 kg/m^3

     Viscosity = 1.7894e-05 kg/m-s

     Water:

     Density = 998.2 kg/m^3

     Viscosity = 0.001003 kg/m-s

PHASES

List/show all phases

     air - Primary Phase

     water - Secondary Phase

II USER DEFINED

Functions --> compiled --> Add

select the udf file --> press ok

press Build

press Load

III SETUP DOMAIN

MESH MODELS

Dynamic Mesh - Tick Dynamic Mesh

click on create/Edit 

Zones Names --> left_gear

Motion UDF/profile --> left_motion

Centre of Gravity location

   x(m) = 0

   y(m) = 0

click on create

Zones Names --> right_gear

Motion UDF/profile --> right_motion

Centre of Gravity location

   x(m) = 0.115

   y(m) = 0

click on create

Mesh Methods - Tick smoothing, Layering, Remeshing

settings --> Remeshing-->Parameters

             Minimum Length scale (m) = 0.0001

             Maximum Length scale (m) = 0.002

click on ok.

Display zone motion

      select - Dynamic Face zones(left_gear and right gear)

      preview the motion of both gears 

      close

ADAPT

Refine/Coarse criteria --> cell registers -->New -->Region   

Name - hexahedron

Input Coordinates

            X min (m) = -0.05612

            X max (m) = 0.17112

            Y min (m) = -0.0675

            Y max (m) = -0.0375

click on save/Display

IV SOLUTION:

INITIALIZATION

Method --> Hybrid

Initialize at t = 0 

Patch 

Phase --> water

variable --> volume Fraction

Registers to patch -->select hexahedron

value -->1

click on Patch

close

V RESULTS

GRAPHICS

 Contour --> New 

     options --Filled

     contours of -->Phases

     phase - water

     surfaces - select all surfaces

     save/Display

     close

VI SOLUTION

ACTIVITIES 

Create --> solutions Animation

        Animation object --> contour-1

        click on preview

        Ok

RUN CALCULATON

Time step size = 0.0001

No. of Time Steps = 10000

Scaled Residuals:

Gearbox sloshing effect of lubricant(water) through gears with small clearance Animation:

Case 2: GearBox with gears, engaged with small clearance: (Gear oil is used as lubricant):

The Geometry, Mesh and simulation Details are same, but lubricant Materials is to be changed from water to Gear oil.

MATERIALS

Create/Edit Materials

      Air: 

     Density = 1.225 kg/m^3

     Viscosity = 1.7894e-05 kg/m-s

     Gear oil:

     Density = 871 kg/m^3

     Viscosity = 0.04006889 kg/m-s

PHASES

List/show all phases

     air - Primary Phase

     Gear oil - Secondary Phase

Scaled Residuals:

Gearbox sloshing effect of lubricant(Gear oil) through gears with small clearance Animation:

case 3: GearBox with gears, engaged with increased clearance: (water is used as lubricant):

Geometry

Gears engaged with increased clearance(Distance between the centres of gears is 117 mm:

Right Gear is 48.55151 mm from origin X0

Left Gear is -68.44848 mm from origin X0

2D Gear:

2D Gear Mesh:

SIMULATION SETUP DETAILS:

I. SETUP PHYSICS

SOLVER

     Type --> pressure based

     velocity Formulation --> Absolute

     Time --> Transient

     2D space --> planar

     Gravity - Tick the check box

     Gravitational Acceleration 

            X (m/s2) = 0

            Y (m/s2) = -9.81

MODELS

 Viscous --> k-epsilon

 k-epsilon Model --> Reliazable

 Near-wall Treatment --> Enhanced wall treatment

 Multiphase

      Model --> volume of Fluid

      Formulation --> Implicit

MATERIALS

Create/Edit Materials

      Air: 

     Density = 1.225 kg/m^3

     Viscosity = 1.7894e-05 kg/m-s

     Water:

     Density = 998.2 kg/m^3

     Viscosity = 0.001003 kg/m-s

PHASES

List/show all phases

     air - Primary Phase

     water - Secondary Phase

II USER DEFINED

Functions --> compiled --> Add

select the udf file --> press ok

press Build

press Load

III SETUP DOMAIN

MESH MODELS

Dynamic Mesh - Tick Dynamic Mesh

click on create/Edit 

Zones Names --> left_gear

Motion UDF/profile --> left_motion

Centre of Gravity location

   x(m) = -0.06844848

   y(m) = 0

click on create

Zones Names --> right_gear

Motion UDF/profile --> right_motion

Centre of Gravity location

   x(m) = 0.04855151

   y(m) = 0

click on create

Mesh Methods - Tick smoothing, Layering, Remeshing

settings --> Remeshing-->Parameters

             Minimum Length scale (m) = 0.0001

             Maximum Length scale (m) = 0.002

click on ok.

Display zone motion

      select - Dynamic Face zones(left_gear and right gear)

      preview the motion of both gears 

      close

ADAPT

Refine/Coarse criteria --> cell registers -->New -->Region   

Name - hexahedron

Input Coordinates

            X min (m) = -0.1257721

            X max (m) = 0.1058752

            Y min (m) = -0.0685

            Y max (m) = -0.0375

click on save/Display

IV SOLUTION:

INITIALIZATION

Method --> Hybrid

Initialize at t = 0 

Patch 

Phase --> water

variable --> volume Fraction

Registers to patch -->select hexahedron

value -->1

click on Patch

close

V RESULTS

GRAPHICS

 Contour --> New 

     options --Filled

     contours of -->Phases

     phase - water

     surfaces - select all surfaces

     save/Display

     close

VI SOLUTION

ACTIVITIES 

Create --> solutions Animation

        Animation object --> contour-1

        click on preview

        Ok

RUN CALCULATON

Time step size = 0.0001

No. of Time Steps = 10000

Scaled Residuals:

Gearbox sloshing effect of lubricant(water) through gears with increased clearance Animation:

Case 4: GearBox with gears, engaged with increased clearance: (Gear oil is used as lubricant):

The Geometry, Mesh and simulation Details are same, but lubricant Materials is to be changed from water to Gear oil.

MATERIALS

Create/Edit Materials

      Air: 

     Density = 1.225 kg/m^3

     Viscosity = 1.7894e-05 kg/m-s

     Gear oil:

     Density = 871 kg/m^3

     Viscosity = 0.04006889 kg/m-s

PHASES

List/show all phases

     air - Primary Phase

     Gear oil - Secondary Phase

Scaled Residuals:

 

Gearbox sloshing effect of lubricant(gear oil) through gears with increased clearance Animation:

Conclusion:

  • The viscosity of water is less than the viscosity of gear oil, sloshing effect is more in case of water as compared to gear-oil.
  • Most part of oil is stuck in between gear teeth, but in case of water it tries to settle down.
  • Gearbox with less amount of water does not allow to settle down.
  • Gearbox with more amount of gear-oil is filled, for effective functioning. 

Projects by Shravankumar Nagapuri

 

Objectives:

  • To import a 3D Geometry of elbow into CONVERGE studio.
  • To add boundaries and setup the case in CONVERGE and run the elbow flow simulation using Cygwin.
  • To post Process the results usi Read more

Objectives: To import a 3D Geometry of elbow into CONVERGE studio. To add boundaries and setup the case in CONVERGE and run the elbow flow simulation using Cygwin. To post Process the results using Paraview Importing the Geometry: Open the CONVERGE studi Read more

 Objectives: To create a 3D Geometry of Backward facing step using CONVERGE studio. To setup the case in CONVERGE and run the Backward facing step flow simulation for three different mesh sizes using Cygwin. To post Process the results using Paraview To compa Read more

Objectives: To setup the case in CONVERGE and run the channel flow simulation for three different mesh sizes using Cygwin. To post Process the results using Paraview To compare the results of three simulation Description:   The fluid which flows throu Read more

OBJECTIVE: To Mesh the Cylinder model using ANSA PROCEDURE: Import the stp model file into ANSA Graphical USer Interface. By Default the model is in wire frame model, for proper 3D visualization enable shadow mode. By Default the model is in entity mode, change it Read more

Objectives: To perform a parametric study on the gate valve simulation. To obtain the mass flow rates at the outlet for 5 design points. To show the cut section view for different design points, and also to show the gate disc lift and fluid volume extraction. To s Read more

Objectives: To Write a Matlab program that can generate the computational blockMesh file  automatically for a wedge angle of 3 degrees and compare the results obtained for Symmetry BC and Wedge BC. To Write a Matlab program that takes an angle as input and gene Read more

1Q. Briefly explain about the possible types of combustion simulations in FLUENT. A:  Combustion or burning is a high temperature exothermic chemical reaction between a fuel and an oxidant accompanied by the production of heat, light and unburnt gases in the fo Read more

Cyclone Separator: Principle and Working: A high speed rotating (air)flow is established within a cylindrical or conical container called a cyclone. Air flows in a spiral pattern, beginning at the top (wide end) of the cyclone and ending at the bottom (narrow) end bef Read more


Loading...

The End