0.0
MODEL 1: SINGLE HEATED ROD IN A FINITE POOL
0.1
General
The model provides the two dimensional results for a single heated rod in a stagnant pool. The
geometry is shown in Figure 0.1-1.
Figure 0.1-1: Geometry
0.2
Objective
Show that the heated rod creates a change in temperature and that the hot water rises due to
buoyancy effects caused by density change.
0.3
Mesh
The quality of the mesh plays a significant role in the accuracy and stability of the numerical
computation. Depending on the meshing options different meshes are created that have varying
effectiveness when determining the results for a given geometry. Three statistics that are
important when judging the effectiveness of a mesh type are orthogonal quality, aspect ratio and
skewness. Orthogonal quality of a cell is the minimum value that results from calculating the
normalized dot product of the area vector of a face and a vector from the centroid of the cell to
the centroid of that face and the normalized dot product of the area vector of a face and a vector
from the centroid of the cell to the centroid of the adjacent cell that shares that face. Therefore,
the worst cells will have an orthogonal quality closer to 0 and the best cells will have an
orthogonal quality closer to 1. Aspect ratio is a measure of the stretching of the cell. Skewness
is defined as the difference between the shape of the cell and the shape of an equilateral cell of
equivalent volume. Highly skewed cells can decrease accuracy and destabilize the solution.
To generate an effective mesh, the minimum orthogonal quality should be as large as possible
and the maximum aspect ratio and the maximum skewness should be as small as possible. (Text
taken from ANSYS User’s Manual, Section 6.2.2, “Mesh Quality”)
Figure 0.3-1: Automatic Method (Quadrilateral Dominant)
Figure 0.3-2: Triangle Method
Figure 0.3-3: Uniform Quadrilateral (Element Size: 5 mm)
Figure 0.3-4: Uniform Quadrilateral/Triangles (Element Size: 20 mm)
Figure 0.3-5: Uniform Quadrilateral/Triangles (Element Size: 5 mm)
Table 0.3-1: Mesh Type Characteristics
Mesh Type
Automatic Method
(Quadrilateral Dominant)
Triangle Method
Uniform Quadrilateral
(Element Size: 5 mm)
Uniform Quadrilateral/Triangles
(Element Size: 20 mm)
Uniform Quadrilateral/Triangles
(Element Size: 5 mm)
Orthogonal
Quality
0.8075
Aspect Ratio
Skewness
1.6278
0.5618
0.8091
0.8167
1.7710
1.7211
0.3280
0.4829
0.8763
1.4366
0.4317
0.8215
1.6570
0.4923
Comparing the three mesh statistics, the Uniform Quadrilateral/Triangles with and Element Size
of 5 mm is the best overall mesh. It has the greates Orthogonal Quality, the second lowest
Aspect Ratio and low Skewness. Therefore this mesh type is used for the analysis.
0.4
Active Models
All other models are turned off except the Energy Equation and the Viscous model is set to
laminar.
0.5
Material Properties
The fluid is liquid water provided by FLUENT (h2o<l>). The solid is aluminum provided by
FLUENT (al). The fluid properties (specific heat, thermal conductivity, viscosity and molecular
weight) are held constant and density is determined based on the incompressible, ideal gas
model. The solid properties (density, specific heat and thermal conductivity) are held constant.
0.6
Boundary Conditions
To make setting the mesh boundary conditions easier, each wall is distinctly named (shown
below).
Figure 0.6-1: Boundary Conditions
The boundary conditions for the above geometry are as follows. The top, bottom, left and right
boundaries are equivalent. They are treated as a “wall” with the momentum conditions of a
stationary wall with no slip shear. The thermal condition is a constant temperature of 300 K.
The inner_rod boundary is treated as a “wall” with the momentum conditions of a stationary wall
with no slip shear. The thermal condition is a constant temperature of 400 K. The interiorsurface_body boundary is treated as an “interior.”
0.7
Initial Conditions
Pressure: 101300 Pa
Temperature: 300 K
Gravity: -9.8 m/s2 in y-direction
0.8
Results
When the fluid density properties are held constant the following temperature profile is created.
Figure 0.8-1: Temperature
This example is very simple but the impact of mesh quality is noticeable when comparing the
static temperature image below to the one shown above. Notice that when a more coarse mesh
(Uniform Quadrilateral/Triangles with an Element Size of 20 mm) is used the temperature
gradient changes and becomes more rigid.
Figure 0.8-2: Temperature
The results of the working model are shown below (temperature, density and velocity plots). Get
image from well know reference showing similar results. Explain how results are similar and the
model is working as expected.
Figure 0.8-3: Temperature
Figure 0.8-4: Velocity
Figure 0.8-5: Density
0.9
Conclusion
Based on the modeling choices and boundary conditions, the model is working as expected. The
small difference in temperature between the heated rod and the bulk fluid caused just enough of a
heatup to create natural convection. The mesh type also played a crucial role. The results given
by the coarse mesh analysis proved to not be mesh independent. Therefor the mesh was refined
and new results were obtained. The new results are mesh independent and are correct.
1.0
MODEL 1: SINGLE HEATED ROD IN AN INFINITE POOL
1.1
General
The model provides the two dimensional results for a single heated rod in a stagnant pool. The
geometry is shown in Figure 1.1-1.
Figure 1.1-1: Geometry
1.2
Objective
Show that the heated rod creates a change in temperature and that the hot water rises due to
density change.
1.3
Mesh
Figure 1.3-1: Mesh
Mesh Method: Triangle
Orthogonal Quality: 0.75814
Aspect Ratio: 4.129
1.4
Active Models
All models are turned off except the Energy Equation and the Viscous model is set to laminar.
The active models are shown in Figure 1.4-1.
Figure 1.4-1: Active Models
1.5
Material Properties
The fluid is liquid water provided by FLUENT (h2o<l>). The solid is aluminum provided by
FLUENT (al). The fluid properties (specific heat, thermal conductivity, viscosity and molecular
weight) are held constant and density is determined based on a piecewise linear interpolation.
The solid properties (density, specific heat and thermal conductivity) are held constant.
Table 1.5-1: Fluid Density Properties
Temperature (°F)
273
308
348
373
Density (lbm/ft3)
999.9
994.1
974.9
958.4
Figure 1.5-1: Model Material Properties
1.6
Boundary Conditions
The boundary conditions for the geometry in Figure 1.1-1 are as follows:
Top: Pressure Outlet
Outlet Gauge Pressure: 0 psi
Backflow Temperature: 300 K
Bottom: Pressure Inlet
Inlet Gauge Pressure: -3.103407 psi
Backflow Temperature: 300 K
Left / Right: Wall
Specified Shear Stress: 0
Heat Flux: 0 W/ft2
Cylinder: Wall
No Slip
Temperature: 310 K
1.7
Initial Conditions
Pressure: 101325 Pa
Temperature: 300 K
Y Velocity: 0 m/s
Gravity: -9.8 m/s2 in y-direction
1.8
Solution Methods
Scheme: Piso
Gradient: Least Squares Cell Based
Pressure: PRESTO!
Momentum: Second Order Upwind
Energy: Second Order Upwind
Transient Formulation: Second Order Implicit
1.9
Results
1.9.1 Incorrect Modeling of Density
When the fluid density properties are held constant the following temperature profile is created.
Figure 1.9.1-1: Temperature for Constant Density Model
This example is very simple but the impact of mesh quality is noticeable when comparing the
static temperature image below to the one shown above. Notice that when a more coarse mesh
(Uniform Quadrilateral/Triangles with an Element Size of 20 mm) is used the temperature
gradient changes and becomes more rigid.
Figure 1.9.1-2: Temperature with Constant Density and Coarse Mesh
1.9.2 Correct Modeling of Density
The results of the working model are shown below (temperature, density and velocity plots). Get
image from well know reference showing similar results. Explain how results are similar and the
model is working as expected.
Figure 1.9.2-1: Density
Figure 1.9.2-2: Velocity
Figure 1.9.2-3: Velocity Vectors
Figure 1.9.2-4: Temperature
Figure 1.9.2-5: Isotherms
Figure 1.9.2-6: Isotherms around a Horizontal Tube in Free convection
Add Figure 93 p. 167 from Introduction to the Transfer of Heat and Mass
1.10
Conclusion
The modeling of a horizontal cylinder submerged in an infinite pool using ANSYS Fluent 14.0
shows good resemblance to experimental data. The isotherms shown in Figure 1.9.2-5 are very
similar in size and shape to those measured experimentally shown in Figure 1.9.2-6.
2.0
MODEL 2: NATURAL CONVECTION OVER A VERTICAL PLATE
2.1
General
This is a two-dimensional model showing natural convection of a heated vertical plate in an
infinite stagnant pool.
Figure 2.1-1: Geometry
2.2
Objective
Show that the vertical plate creates a change in temperature and that the hot water rises due to
density change along the plate. Compare to known experimental data and show that model
shows comparable results.
2.3
Mesh
Figure 2.3-1: Mesh
Mesh Method: Triangle
Orthogonal Quality: 0.69087
Aspect Ratio: 4.7072
2.4
Active Models
Energy equation and density change (user specified table), fluid flow is laminar. The active
models are shown in Figure 2.4-1.
Figure 2.4-1: Active Models
2.5
Material Properties
The fluid is liquid water provided by FLUENT (h2o<l>). The solid is aluminum provided by
FLUENT (al). The fluid properties (specific heat, thermal conductivity, viscosity and molecular
weight) are held constant and density is determined based on a piecewise linear interpolation.
The solid properties (density, specific heat and thermal conductivity) are held constant.
Table 2.5-1: Fluid Density Properties
Temperature (°F)
273
308
348
373
Density (lbm/ft3)
999.9
994.1
974.9
958.4
Figure 2.5-1: Material Properties
2.6
Boundary Conditions
The boundary conditions for the above geometry are as follows:
Top: Pressure Outlet
Outlet Gauge Pressure: 0 psi
Backflow Temperature: 300 K
Bottom: Pressure Inlet
Inlet Gauge Pressure: -2.216723 psi
Backflow Temperature: 300 K
Left / Right: Wall
Specified Shear Stress: 0
Heat Flux: 0 W/ft2
Heated Plate: Wall
No Slip
Temperature: 310 K
2.7
Initial Conditions
The initial conditions used in this analysis are as follows:
Pressure: 101300 Pa
Temperature: 300 K
X Velocity: 0 m/s
Y Velocity: 0 m/s
Gravity: -9.8 m/s2 in y-direction
2.8
Solution Methods
The solutions methods used in this analysis are shown in Figure 2.8-1.
Figure 2.8-1: Solution Methods
2.9
Results
Using the geometry, mesh, inputs and solutions methods discussed above, the results shown in
Figures 2.9-1 through 2.9-X were obtained. The mass conservation for the top and bottom
boundaries are as follows:
The results are mesh independent and mass is conserved within model volume. Therefore the
results are valid.
Figure 2.9-1: Static Pressure
Figure 2.9-2: Total Pressure
Figure 2.9-3: Density
Figure 2.9-4: Temperature
Figure 2.9-5: Isotherms
Figure 2.9-6: Velocity
Figure 2.9-7: Velocity Vectors
Figure 2.9-8: Momentum Boundary Layer
Figure 2.9-9: Thermal Boundary Layer
Figure 2.9-10: Density Plot
Figure 2.9-11: Temperature Plot
Figure 2.9-12: Velocity Plot
Figure 2.9-13: Experimental Isotherms
Add Figure 94 on p. 168 from Introduction to the Transfer of Mass and Energy
Figure 2.9-14: Thermal Boundary Layer
Add Figure 17-3 p. 371 from Convective Heat and Mass Transfer
Figure 2.9-15: Momentum Boundary Layer
Add Figure 17-2 p. 371 from Convective Heat and Mass Transfer
2.10
Conclusion
The modeling of a heated vertical plate submerged in an infinite pool using ANSYS Fluent 14.0
shows good resemblance to experimental data. The isotherms shown in Figure 2.9-5 are very
similar in size and shape to those measured experimentally shown in Figure 2.9-13. The plot of
temperature vs. distance from the plate shown in Figure 2.9-11 matches Figure 2.9-14 well. The
plot of velocity vs. distance from the plate shown in Figure 2.9-12 matches Figure 2.9-15 well.
3.0
MODEL 3: TURBULENCE IN A PIPE
3.1
General
This is a two-dimensional model showing turbulent flow in a circular pipe.
Figure 3.1-1: Geometry
3.2
Objective
Show that the flow within a circular pipe is turbulent and that the velocity profiles are
comparable to known experimental data.
3.3
Mesh
Figure 3.4-1: Mesh
Figure 3.4-2: Mesh Zoomed In
Mesh Method: Quadrilateral Dominant
Orthogonal Quality: 0.779464
Aspect Ratio: 5.07881
3.4
Active Models
Energy equation and density change (user specified table), fluid flow is laminar. The active
models report provided by FLUENT is shown in Figure 3.4-1.
Figure 3.4-1: Active Models
3.5
Material Properties
The fluid is liquid water provided by FLUENT (h2o<l>). The solid is aluminum provided by
FLUENT (al). The fluid properties (specific heat, thermal conductivity, density, viscosity and
molecular weight) are held constant. The solid properties (density, specific heat and thermal
conductivity) are also held constant. See Figure 3.5-1 for the FLUENT provided material
properties report.
Figure 3.5-1: Material Properties
3.6
Boundary Conditions
The boundary conditions for the geometry shown in Figure 3.1-1 are as follows:
Right: Pressure Outlet
Backflow Turbulent Intensity: 4.01604%
Backflow Hydraulic Diameter: 0.02 m
Left: Mass Flow Inlet
Mass Flow Rate: 1 kg/s
Turbulent Intensity: 4.01604%
Hydraulic Diameter: 0.02 m
Top: Wall – No Slip
Roughness Height: 0.01 m
Roughness Constant: 0.5
Bottom: Axis
3.7
Calculation of Turbulent Parameter Inputs
The following calculations were performed to determine the boundary condition and initial
condition inputs for the turbulence model.
Mass Flow Rate: 1 kg/s (randomly chosen flow rate that will give turbulent flow)
Pipe Diameter (D): 0.02 m
Viscosity (μ): 0.001003 kg/m-s
Density (ρ): 998.2 kg/m3
Turbulence Empirical Constant (Cμ) = 0.09 (recommendation from ANSYS Theory Guide)
Hydraulic Diameter (Dh):
𝐷ℎ =
𝐷 2
𝜋 ∗ (2)
4∗𝐴
=
= 𝐷 = 0.02 𝑚
𝑃
4∗𝜋∗𝐷
Flow Area (A):
𝐷 2
0.02 𝑚 2
𝐴 = 𝜋∗( ) =𝜋∗(
) = 0.00031416 𝑚2
2
2
Average Flow Velocity (uavg):
𝑢𝑎𝑣𝑔 =
𝑚̇
=
𝜌∗𝐴
1 𝑘𝑔/𝑠
998.2
𝑘𝑔
∗ 0.00031416 𝑚2
𝑚3
= 3.1889
𝑚
𝑠
Reynolds Number (ReDh):
𝑅𝑒𝐷ℎ
𝑚̇𝐷ℎ
=
=
𝜇𝐴
𝑘𝑔
1 𝑠 ∗ 0.02 m
= 63471.6
𝑘𝑔
0.001003 𝑚 − 𝑠 ∗ 0.00031415 𝑚2
Turbulence Length Scale (l):
𝑙 = 0.07 ∗ 𝐷ℎ = 0.07 ∗ 0.02 𝑚 = 0.0014 𝑚
Turbulent Intensity (I):
−
1
1
𝐼 = 0.16 ∗ 𝑅𝑒𝐷ℎ8 = 0.16 ∗ 63471.6−8 = 0.0401604
Turbulent Kinetic Energy (k):
2
3
3
𝑚
𝑚2
2
𝑘 = (𝑢𝑎𝑣𝑔 ∗ 𝐼) = (3.1889 ∗ 0.0401604) = 0.024601 2
2
2
𝑠
𝑠
Specific Dissipation Rate (ω):
𝝎=
3.8
𝒌𝟏/𝟐
𝟏/𝟒
𝑪𝝁
∗𝒍
=
𝟎. 𝟎𝟐𝟒𝟔𝟎𝟏𝟏/𝟐
𝟏
= 𝟐𝟎𝟒. 𝟓𝟒
𝟏/𝟒
𝒔
𝟎. 𝟎𝟗 ∗ 𝟎. 𝟎𝟎𝟏𝟒
Initial Conditions
The initial conditions used in this analysis and calculated in Section 3.8 are as follows:
Pressure: 101325 Pa
Axial Velocity: 3.1889 m/s
Radial Velocity: 0.0 m/s
Turbulent Kinetic Energy: 0.024601 m2/s2
Specific Dissipation Rate: 204.544 1/s
3.9
Solution Methods
The solutions methods used in this analysis are shown in Figure 3.9-1.
Figure 3.9-1: Solution Methods
3.10
Results
Using the geometry, mesh, inputs and solutions methods discussed above, the results shown in
Figures 3.10-1 through 3.10-9 were obtained. The mass conservation for the top and bottom
boundaries are as follows:
The results are mesh independent and mass is conserved within model volume. Therefore the
results are valid.
Figure 3.10-1: Static Pressure
Figure 3.10-2: Total Pressure
Figure 3.10-3: Velocity
Figure 3.10-4: Velocity Vectors
Figure 3.10-5: Turbulent Kinetic Energy
Figure 3.10-6: Production of Turbulent Kinetic Energy
Figure 3.10-7: Specific Dissipation Rate
Figure 3.10-8: Plot of Wall Shear Stress
Figure 3.10-9: Velocity vs. Position at Various Axial Heights
Figure 3.10-10: Experimental Data
Use the experimental data from Turbulence by Hinze. This book has a number of plots with
experimental data.
3.11
Conclusion
The modeling of a heated vertical plate submerged in an infinite pool using ANSYS Fluent 14.0
shows good resemblance to experimental data. The velocity profiles shown in Figure 3.10-9 are
very similar in size and shape to those measured experimentally shown in Figure 3.10-10.
4.0
MODEL 3: TURBULENT FLOW IN A PIPE WITH CONSTANT HEAT FLUX
4.1
General
This is a two-dimensional model showing turbulent flow in a circular pipe. Figure 4.1-1 shows
the geometry used.
Figure 4.1-1: Geometry
4.2
Objective
Show that the flow within a circular pipe is turbulent and that the velocity profiles are
comparable to known experimental data. Show that the results for constant heat flux heat
transfer is comparable to known experimental data.
4.3
Mesh
Figure 3.4-1: Mesh
Figure 3.4-2: Mesh Zoomed In
Mesh Method: Quadrilateral Dominant
Orthogonal Quality: 0.808863
Aspect Ratio: 4.86242
4.4
Active Models
Energy equation and density change (user specified table), fluid flow is laminar. The active
models report provided by FLUENT is shown in Figure 4.4-1.
Figure 4.4-1: Active Models
4.5
Material Properties
The fluid is liquid water provided by FLUENT (h2o<l>). The solid is aluminum provided by
FLUENT (al). The fluid properties (specific heat, thermal conductivity, density, viscosity and
molecular weight) are held constant. The solid properties (density, specific heat and thermal
conductivity) are also held constant. See Figure 4.5-1 for the FLUENT provided material
properties report.
Figure 3.5-1: Material Properties
4.6
Boundary Conditions
The boundary conditions for the geometry shown in Figure 3.1-1 are as follows:
Right: Pressure Outlet
Backflow Turbulent Intensity: 4.01604 %
Backflow Hydraulic Diameter: 0.02 m
Backflow Temperature: 300 K
Left: Mass Flow Inlet
Mass Flow Rate: 1 kg/s
Turbulent Intensity: 4.01604 %
Hydraulic Diameter: 0.02 m
Inlet Temperature: 300 K
Top: Wall – No Slip
Roughness Height: 0.01 m
Roughness Constant: 0.5
Heat Flux: 665586 W/m2
Bottom: Axis
4.7
Calculate Required Heat Flux
The following calculations were performed to determine the required heat flux to generate an
increase the average exit temperature by 5°C.
Mass Flow Rate: 1 kg/s (randomly chosen flow rate that will give turbulent flow)
Pipe Diameter (D): 0.02 m
Pipe Length (L): 0.5 m
Specific Heat (Cp): 4132 J/kg-K
Energy Input Required (Q):
𝑘𝑔
𝐽
𝑄̇ = 𝑚̇ ∗ 𝐶𝑝 ∗ ∆𝑇 = 1 𝑠 ∗ 4132 𝑘𝑔−𝐾 ∗ 5°𝐶 = 20910 𝑊
Surface Area (As):
𝐴𝑠 = 𝜋 ∗ 𝐷 ∗ 𝐿 = 𝜋 ∗ 0.02 𝑚 ∗ 0.5 𝑚 = 0.031415 𝑚2
Heat Flux (HF):
𝐻𝐹 =
𝑄̇
20910 𝑊
𝑊
=
= 665586 2
2
𝐴𝑠 0.031415 𝑚
𝑚
Therefore the heat flux used as the wall boundary conditions is 665586 W/m2.
4.8
Initial Conditions
The initial conditions used in this analysis and calculated in Section 3.8 are as follows:
Pressure: 101325 Pa
Axial Velocity: 3.1889 m/s
Radial Velocity: 0.0 m/s
Fluid Temperature: 300 K
Turbulent Kinetic Energy: 0.024601 m2/s2
Specific Dissipation Rate: 204.544 1/s
4.9
Solution Methods
The solutions methods used in this analysis are shown in Figure 4.9-1.
Figure 4.9-1: Solution Methods
4.10
Results
Using the geometry, mesh, inputs and solutions methods discussed above, the results shown in
Figures 3.10-1 through 3.10-9 were obtained. The mass conservation for the inlet and outlet
boundaries are as follows:
The results are mesh independent and mass is conserved within model volume. Therefore the
results are valid.
This model is an extension of Model 3 shown in Section 3.0. Model 4 extends the length of the
pipe to be 0.5 m and adds a surface heat flux. Therefore, only figures and plots applicable to
heat transfer are shown in Section 4.10. For figures and plots applicable to mass and momentum
transfer, see Section 3.10.
Figure 4.10-1: Temperature
Figure 4.10-2: Various Axial Temperatures
Figure 4.10-3: Radial Exit Temperatures
Figure 4.10-4: Surface Heat Transfer Coefficient
Figure 4.10-5: Experimental Data
Use the experimental data from Turbulence by Hinze. This book has a number of plots with
experimental data.
Figure 4.10-6 shows that the mass weighted average of the entire circular pipe is 302.66 K.
Figure 4.10-6: Weighted Average Temperature
Figure 4.10-7 shows that the minimum temperature in the circular pipes 300.00 K and the
maximum temperature in the circular pipe is 306.44 K.
Figure 4.10-7: Minimum / Maximum Temperature
Figure 4.10-8 shows the mass weighted average total temperature at different radial sections.
The inlet is the coolest section and the average temperature increases as the distance from the
entrance increases. The average outlet temperature at 50 cm is less than the average temperature
at 49.5 cm because small amounts fluid at a temperature of 300 K enters the control volume at
the outlet to conserve mass which reduces the average temperature.
Figure 4.10-8: Various Radial Average Temperatures
4.11
Conclusion
The modeling of a circular pipe with a constant heat flux and turbulent flow using ANSYS
Fluent 14.0 shows good resemblance to experimental data. The temperature profile shown in
Figure 4.10-1 is logical. The temperature profiles shown in Figures 4.10-2 and 4.10-3show
reasonable results. The average outlet temperature, at 49.5 cm from the entrance, is almost 5 K
warmer than the entrance which is expected and proves that energy is conserved.
Model 3: Multiple Heated Rods with Laminar Cross-Flow
General:
2-dimensional, low flow, four heated rods (show geometry image)
Objective:
Show that the heated rods create a change in temperature and that the hot water rises due to
density change. Hottest point should be above and to the right of the heated rods. Coldest point
should be where the flow enters the region.
Models:
Energy equation and density change (incompressible, ideal gas), fluid flow is laminar.
Mesh:
Show picture of mesh. Explain what was done and the named regions. Show the skewness and
oblique quality.
Material Properties:
FLUENT provided liquid water. All properties are constant except for density (incompressible,
ideal gas). Solid is FLUENT provided aluminum properties (all constant).
Input:
Energy model turned on. Fluid flow is laminar.
Boundary Conditions:
Show image of geometry and call out how each wall is treated.
The top and bottom external walls are treated as a “wall” with a temperature of 300 K. The
heated rods are a “wall” with a temperature of 400 K. The left wall is a mass-flux-inlet with a
flow of 0.05 lbm/s. The outlet is either a pressure-outlet or a flux outlet.
Initial Conditions:
Pressure: 101300 Pa
Temperature: 300 K
Gravity: -9.8 m/s^2 in y-direction
Results:
Show how the outlet boundary conditions change the temperature profile.
Show results of working model (temperature, density and velocity plots). Get image from well
know reference showing similar results. Explain how results are similar and the model is
working as expected.
Conclusion:
Model is working as expected. Explain how the outlet boundary condition changes the results.
Talk about what is more accurate based on experimental results.
Model 4: Single Heated Rods with Laminar Axial-Flow
General:
2-dimensional, low flow, single heated rods (show geometry image)
Objective:
Show that the heated rod creates a change in temperature and that the water heats up as it travels
along the rod. Hottest point should be at the top of the rod prior to the exit. Coldest point should
be at the bottom where the flow enters the region.
Models:
Energy equation and density change (incompressible, ideal gas), fluid flow is laminar.
Mesh:
Show picture of mesh. Explain what was done and the named regions. Show the skewness and
oblique quality.
Material Properties:
FLUENT provided liquid water. All properties are constant except for density (incompressible,
ideal gas). Solid (heated rod) is FLUENT provided aluminum properties (all constant).
Input:
Energy model turned on. Fluid flow is laminar.
Boundary Conditions:
Show image of geometry and call out how each wall is treated.
The left external wall is treated as a “wall” with a temperature of 300 K. The right wall is the
heated wall and is considered a “wall” with a temperature of 400 K. The bottom wall is a massflux-inlet with a flow of 0.05 lbm/s. The top wall is a pressure-outlet.
Initial Conditions:
Pressure: 101300 Pa
Temperature: 300 K
Gravity: -9.8 m/s^2 in y-direction
Results:
Show results of working model (temperature, density and velocity plots). Get image from well
know reference showing similar results. Explain how results are similar and the model is
working as expected.
Conclusion:
Model is working as expected.
Model X:
General:
Objective:
Models:
Mesh:
Material Properties:
Input:
Results:
Conclusion:
Hi Ernesto,
I know we haven't met in a while but I have been making progress on my thesis. I have
completed another model and begun documenting everything to date. Could you please take a
look at the attached document. It contains the explanation of my model development and results.
I want to know if I am including all the necessary points and what needs to be explained further.
There are some holes in the text that I still need to work on but I was hoping for some input from
you before I went too far.
The models I have documented are as follows:
1. Natural convection of a heated rod in a finite pool
2. Natural convection of a heated rod in an infinite pool
3. Natural convection of a heated vertical plate in an infinite pool
4. Turbulence in a circular pipe
5. Turbulent flow in a circular pipe with constant heat flux
I would concentrate most of your time on Models 3 and 4 as these have the most complete writeup. Let me know what you think and we can try to meet at some point next week.
In the meantime, I plan to begin developing my two-phase flow model.
Regards
Matt
5/11/12