Fin Convection Experiment Data Analysis with TNSolver

In the following set of instructions the following data set will be used for demonstration purposes. It is suggested that you organize your data in a similar format:

Forced Convection - Temperature (C)
Fin base TC1 TC2 TC3 TC4 TC5 TC6 ambient power (W)
Al_fin_FC 58.7 49.5 43.5 36.5 31.0 30.0 29.0 23.9 11.12
Cu_fin_FC 46.6 42.7 40.8 37.5 35.7 24.6 8.72
sqCu_fin_FC 39.8 38.2 36.5 34.2 32.0 30.0 30.0 24.3 8.64
SS_fin_FC 68.0 35.6 28.6 25.3 24.5 24.5 24.5 24.0 6.37

Flow Velocity (m/s)
Fin base 1 2 3 4 5 6
Al_fin_FC 1.87 2.80 3.11 3.00 2.37 2.25 1.98
Cu_fin_FC 1.85 2.95 3.27 3.21 2.82
sqCu_fin_FC 1.88 2.65 3.20 3.15 2.78 2.58 2.14
SS_fin_FC 1.56 2.63 3.08 3.15 2.95 2.64 2.24

Natural Convection - Temperature (C)
Fin base TC1 TC2 TC3 TC4 TC5 TC6 ambient power (W)
Al_fin_NC 90.7 83.5 77.9 70.4 63.1 60.9 59.0 24.2 11.12
Cu_fin_NC 80.6 78.3 77.1 74.3 72.9 24.7 8.72
sqCu_fin_NC 67.7 66.3 65.3 63.0 60.4 58.4 58.4 24.5 8.64
SS_fin_NC 86.5 58.2 45.5 33.2 26.6 25.0 25.0 24.1 6.37

1) Forced Convection Correlation Results

The input files which make use of the EFCcyl and EFCdiamond forced convection correlation conductors are:

TNSolver Input Files
Fin Forced Convection
Aluminum, 11.22” Al_fin_FC.inp
Round Copper, 6.77” Cu_fin_FC.inp
Square Copper, 11.22” sqCu_fin_FC.inp
Stainless Steel, 11.22” SS_fin_FC.inp

For each fin, open the input file in an editor and set the boundary temperatures Tc and Tr to ambient and base to base. Here is the Al_fin_FC.inp file in an editor, with the boundary condition values set to the values in the table shown above:

Editing Al_fin_FC.inp

You should verify that the flow velocities are set to the correct values. If not, edit the file and set them to the desired value. Make sure to save the changes you have made.

Now run the model with TNSolver in MATLAB/Octave:

Running Al_fin_FC with TNSolver in MATLAB/Octave
>> tnsolver('Al_fin_FC');

**********************************************************
*                                                        *
*          TNSolver - A Thermal Network Solver           *
*                                                        *
*             Version 0.9.2, August 9, 2017              *
*                                                        *
**********************************************************

Reading the input file: Al_fin_FC.inp

Initializing the thermal network model ...

Starting solution of a steady thermal network model ...

     Nonlinear Solve
  Iteration    Residual
  ---------  ------------
        1     54.6816
        2     0.337734
        3     0.000168644
        4     6.92131e-08
        5     3.05718e-11

Results have been written to: Al_fin_FC.out

Node results have been written to: Al_fin_FC_nd.csv

Conductor results have been written to: Al_fin_FC_cond.csv

All done ...

>> 

Now open the output file Al_fin_FC.out in your favorite editor in order to find the heat transfer coefficient data from the correlations:

Editing Al_fin_FC.out

Repeat this process for each of the four fins. These are the heat transfer coefficients, using the forced convection correlation, that you want to compare to your h from the least squares analysis with the analytical fin experiment.


2) Natural Convection Correlation Results

Natural Convection - Temperature (C)
Fin base TC1 TC2 TC3 TC4 TC5 TC6 ambient power (W)
Al_fin_NC 90.7 83.5 77.9 70.4 63.1 60.9 59.0 24.2 11.12
Cu_fin_NC 80.6 78.3 77.1 74.3 72.9 24.7 8.72
sqCu_fin_NC 67.7 66.3 65.3 63.0 60.4 58.4 58.4 24.5 8.64
SS_fin_NC 86.5 58.2 45.5 33.2 26.6 25.0 25.0 24.1 6.37

The input files which make use of the ENChcyl natural convection correlation conductors are:

TNSolver Input Files
Fin Natural Convection
Aluminum, 11.22” Al_fin_NC.inp
Round Copper, 6.77” Cu_fin_NC.inp
Square Copper, 11.22” sqCu_fin_NC.inp
Stainless Steel, 11.22” SS_fin_NC.inp

For each fin, open the input file in an editor and set the boundary temperatures Tc and Tr to ambient and base to base. Here is the Cu_fin_NC.inp file in an editor, with the boundary condition values set to the values in the table shown above:

Editing Cu_fin_NC.inp

Make sure to save the changes you have made.

Now run the model with TNSolver in MATLAB/Octave:

Running Cu_fin_NC with TNSolver in MATLAB/Octave
>> tnsolver('Cu_fin_NC');

**********************************************************
*                                                        *
*          TNSolver - A Thermal Network Solver           *
*                                                        *
*             Version 0.9.2, August 9, 2017              *
*                                                        *
**********************************************************

Reading the input file: Cu_fin_NC.inp

Initializing the thermal network model ...

Starting solution of a steady thermal network model ...

     Nonlinear Solve
  Iteration    Residual
  ---------  ------------
        1     58.3599
        2     1.20591
        3     0.00962502
        4     9.06156e-05
        5     9.66255e-07
        6     1.03889e-08
        7     1.11883e-10

Results have been written to: Cu_fin_NC.out

Node results have been written to: Cu_fin_NC_nd.csv

Conductor results have been written to: Cu_fin_NC_cond.csv

All done ...

>> 

Now open the output file Cu_fin_NC.out in your favorite editor in order to find the heat transfer coefficient data from the correlations:

Editing Cu_fin_NC.out

Repeat this process for each of the four fins. These are the heat transfer coefficients, using the natural convection correlation, that you want to compare to your h from the least squares analysis with the analytical fin experiment.


3) Using a Least-Squares Residual Approach, Find the Emissivity, ε, for the Forced Convection Experimental Data

Forced Convection - Temperature (C)
Fin base TC1 TC2 TC3 TC4 TC5 TC6 ambient power (W)
Al_fin_FC 58.7 49.5 43.5 36.5 31.0 30.0 29.0 23.9 11.12
Cu_fin_FC 46.6 42.7 40.8 37.5 35.7 24.6 8.72
sqCu_fin_FC 39.8 38.2 36.5 34.2 32.0 30.0 30.0 24.3 8.64
SS_fin_FC 68.0 35.6 28.6 25.3 24.5 24.5 24.5 24.0 6.37

For each of the experimental data sets, find the best emissivity that fits your experimental data, using the correlations for the heat transfer coefficient.

TNSolver Input Files
Fin Forced Convection
Aluminum, 11.22” Al_fin_FC.inp
Round Copper, 6.77” Cu_fin_FC.inp
Square Copper, 11.22” sqCu_fin_FC.inp
Stainless Steel, 11.22” SS_fin_FC.inp

For each fin, open the input file in an editor and set the boundary temperatures Tc and Tr to ambient and base to base. Here is the Al_fin_FC.inp file in an editor, with the boundary condition values set to the values in the table shown above:

Editing Al_fin_FC.inp

Note that if you did the first step above, 1) Forced Convection Correlation Results, then you have already set the correct boundary conditions in the file.

You should verify that the flow velocities are set to the correct values. If not, edit the file and set them to the desired value. Make sure to save the changes you have made.

Now run the model with ls_fin_emiss in MATLAB/Octave:

Running ls_fin_emiss with Al_fin_FC.inp in MATLAB/Octave
>>emiss = linspace(0.01,1.0,20);
>>expT = [ 49.5 43.5 36.5 31.0 30.0 29.0 ];
>>beste = ls_fin_emiss('Al_fin_FC', expT, emiss)

**********************************************************
*                                                        *
*          TNSolver - A Thermal Network Solver           *
*                                                        *
*  Modified Version for Least Squares Fit of Emissivity  *
*                                                        *
*             Version 0.9.2, August 9, 2017              *
*                                                        *
**********************************************************

Reading the input file: Al_fin_FC.inp

Initializing the thermal network model ...

Starting solution of a steady thermal network model ...

     Nonlinear Solve
  Iteration    Residual
  ---------  ------------
        1     53.5385
        2     0.00506803
        3     1.75073e-06
        4     8.28495e-10

***** intermediate screen output deleted *****

     Nonlinear Solve
  Iteration    Residual
  ---------  ------------
        1     0.0449049
        2     1.81694e-05
        3     7.53064e-09

Results have been written to: Al_fin_FC.out

Node results have been written to: Al_fin_FC_nd.csv

Conductor results have been written to: Al_fin_FC_cond.csv

All done ...


beste =

    0.4789

The best fit emissivity, beste, is printed to the screen at the end of the run. In addition, a plot of the residual vs. emissivity is provided. Make sure that you actually found the minimum with your chosen range:

Emissivity Residual Plot

Repeat this process for all four forced convection experimental data sets and record the best fit emissivity for each one. How does the emissivity compare to the table value (see Table A.8)? Is the emissivity within physical bounds (0 < ε < 1)?


4) Using a Least-Squares Residual Approach, Find the Emissivity, ε, for the Natural Convection Experimental Data

Natural Convection - Temperature (C)
Fin base TC1 TC2 TC3 TC4 TC5 TC6 ambient power (W)
Al_fin_NC 90.7 83.5 77.9 70.4 63.1 60.9 59.0 24.2 11.12
Cu_fin_NC 80.6 78.3 77.1 74.3 72.9 24.7 8.72
sqCu_fin_NC 67.7 66.3 65.3 63.0 60.4 58.4 58.4 24.5 8.64
SS_fin_NC 86.5 58.2 45.5 33.2 26.6 25.0 25.0 24.1 6.37

For each of the experimental data sets, find the best emissivity that fits your experimental data, using the correlations for the heat transfer coefficient.

TNSolver Input Files
Fin Natural Convection
Aluminum, 11.22” Al_fin_NC.inp
Round Copper, 6.77” Cu_fin_NC.inp
Square Copper, 11.22” sqCu_fin_NC.inp
Stainless Steel, 11.22” SS_fin_NC.inp

For each fin, open the input file in an editor and set the boundary temperatures Tc and Tr to ambient and base to base. Here is the Cu_fin_NC.inp file in an editor, with the boundary condition values set to the values in the table shown above:

Editing Cu_fin_NC.inp

Note that if you did the second step above, 1) Natural Convection Correlation Results, then you have already set the correct boundary conditions in the file.

Make sure to save the changes you have made.

Now run the model with ls_fin_emiss in MATLAB/Octave:

Running ls_fin_emiss with Cu_fin_NC.inp in MATLAB/Octave
>>emiss = linspace(0.01,1.0,20);
>>expT = [ 78.3 77.1 74.3 72.9 ];
>>beste = ls_fin_emiss('Cu_fin_NC', expT, emiss)

**********************************************************
*                                                        *
*          TNSolver - A Thermal Network Solver           *
*                                                        *
*  Modified Version for Least Squares Fit of Emissivity  *
*                                                        *
*             Version 0.9.2, August 9, 2017              *
*                                                        *
**********************************************************


Reading the input file: Cu_fin_NC.inp

Initializing the thermal network model ...

Starting solution of a steady thermal network model ...

     Nonlinear Solve
  Iteration    Residual
  ---------  ------------
        1     57.5138
        2     0.215554
        3     0.00248576
        4     3.29208e-05
        5     4.446e-07
        6     6.022e-09

***** intermediate screen output deleted *****

     Nonlinear Solve
  Iteration    Residual
  ---------  ------------
        1     0.139323
        2     0.00124206
        3     1.24777e-05
        4     1.27279e-07
        5     1.30168e-09

Results have been written to: Cu_fin_NC.out

Node results have been written to: Cu_fin_NC_nd.csv

Conductor results have been written to: Cu_fin_NC_cond.csv

All done ...


beste =

    0.0621

The best fit emissivity, beste, is printed to the screen at the end of the run. In addition, a plot of the residual vs. emissivity is provided. Make sure that you actually found the minimum with your chosen range:

Emissivity Residual Plot

Repeat this process for all four natural convection experimental data sets and record the best fit emissivity for each one. How does the emissivity compare to the table value (see Table A.8)? Is the emissivity within physical bounds (0 < ε < 1)?


5) Using a Least-Squares Residual Approach, Find the Heat Transfer Coefficient for the Forced Convection Experimental Data

Forced Convection - Temperature (C)
Fin base TC1 TC2 TC3 TC4 TC5 TC6 ambient power (W)
Al_fin_C 58.7 49.5 43.5 36.5 31.0 30.0 29.0 23.9 11.12
Cu_fin_C 46.6 42.7 40.8 37.5 35.7 24.6 8.72
sqCu_fin_C 39.8 38.2 36.5 34.2 32.0 30.0 30.0 24.3 8.64
SS_fin_C 68.0 35.6 28.6 25.3 24.5 24.5 24.5 24.0 6.37

For each of the experimental data sets, find the best fit heat transfer coefficient that fits your experimental data, using the emissivity you found in step 3) Using a Least-Squares Residual Approach, Find the Emissivity, ε, for the Forced Convection Experimental Data. The input files you will be using are the convection input files:

TNSolver Input Files
Fin Convection
Aluminum, 11.22” Al_fin_C.inp
Round Copper, 6.77” Cu_fin_C.inp
Square Copper, 11.22” sqCu_fin_C.inp
Stainless Steel, 11.22” SS_fin_C.inp

For each fin, open the input file in an editor and set the boundary temperatures Tc and Tr to ambient and base to base. Set the emissivity value on the surfrad conductors to the value you found in step 3). Here is the Al_fin_C.inp file in an editor, with the boundary condition values set to the values in the table shown above, as well as the emissivity:

Editing Al_fin_C.inp

Now run the model with ls_fin_h in MATLAB/Octave:

Running ls_fin_h with Al_fin_C.inp in MATLAB/Octave
>> h = linspace(30,60,20);
>> expT = [ 49.5 43.5 36.5 31.0 30.0 29.0 ];
>> besth = ls_fin_h('Al_fin_C',expT,h)

**********************************************************
*                                                        *
*          TNSolver - A Thermal Network Solver           *
*                                                        *
*       Modified Version for Least Squares Fit of h      *
*                                                        *
*             Version 0.9.2, August 9, 2017              *
*                                                        *
**********************************************************

Reading the input file: Al_fin_C.inp

Initializing the thermal network model ...

Starting solution of a steady thermal network model ...

     Nonlinear Solve
  Iteration    Residual
  ---------  ------------
        1     50.3294
        2     0.239163
        3     1.9008e-05
        4     8.43839e-13

***** intermediate screen output deleted *****

     Nonlinear Solve
  Iteration    Residual
  ---------  ------------
        1     0.190658
        2     3.79629e-06
        3     4.88472e-13

Results have been written to: Al_fin_C.out

Node results have been written to: Al_fin_C_nd.csv

Conductor results have been written to: Al_fin_C_cond.csv

All done ...


besth =

   44.2105

The best fit convection coefficient, besth, is printed to the screen at the end of the run. In addition, a plot of the residual vs. h is provided. Make sure that you actually found the minimum with your chosen range:

h Residual Plot

Repeat this process for all four forced convection experimental data sets and record the best fit h for each one.


6) Using a Least-Squares Residual Approach, Find the Heat Transfer Coefficient for the Natural Convection Experimental Data

Natural Convection - Temperature (C)
Fin base TC1 TC2 TC3 TC4 TC5 TC6 ambient power (W)
Al_fin_C 90.7 83.5 77.9 70.4 63.1 60.9 59.0 24.2 11.12
Cu_fin_C 80.6 78.3 77.1 74.3 72.9 24.7 8.72
sqCu_fin_C 67.7 66.3 65.3 63.0 60.4 58.4 58.4 24.5 8.64
SS_fin_C 86.5 58.2 45.5 33.2 26.6 25.0 25.0 24.1 6.37

For each of the natural convection experimental data sets, find the best fit heat transfer coefficient that fits your experimental data, using the emissivity you found in step 4) Using a Least-Squares Residual Approach, Find the Emissivity, ε, for the Natural Convection Experimental Data. The input files you will be using are the convection input files:

TNSolver Input Files
Fin Convection
Aluminum, 11.22” Al_fin_C.inp
Round Copper, 6.77” Cu_fin_C.inp
Square Copper, 11.22” sqCu_fin_C.inp
Stainless Steel, 11.22” SS_fin_C.inp

For each fin, open the input file in an editor and set the boundary temperatures Tc and Tr to ambient and base to base. Set the emissivity value on the surfrad conductors to the value you found in step 3). Here is the Cu_fin_C.inp file in an editor, with the boundary condition values set to the values in the table shown above, as well as the emissivity:

Editing Cu_fin_C.inp

Now run the model with ls_fin_h in MATLAB/Octave:

Running ls_fin_h with Cu_fin_C.inp in MATLAB/Octave
>> h = linspace(2,12,20);
>> expT = [ 78.3 77.1 74.3 72.9 ];
>> besth = ls_fin_h('Cu_fin_C',expT,h)

**********************************************************
*                                                        *
*          TNSolver - A Thermal Network Solver           *
*                                                        *
*       Modified Version for Least Squares Fit of h      *
*                                                        *
*             Version 0.9.2, August 9, 2017              *
*                                                        *
**********************************************************

Reading the input file: Cu_fin_C.inp

Initializing the thermal network model ...

Starting solution of a steady thermal network model ...

     Nonlinear Solve
  Iteration    Residual
  ---------  ------------
        1     132.444
        2     0.081304
        3     1.98662e-07
        4     1.81884e-12

***** intermediate screen output deleted *****

     Nonlinear Solve
  Iteration    Residual
  ---------  ------------
        1     0.186277
        2     8.20996e-07
        3     3.5291e-13

Results have been written to: Cu_fin_C.out

Node results have been written to: Cu_fin_C_nd.csv

Conductor results have been written to: Cu_fin_C_cond.csv

All done ...


besth =

   10.9474

The best fit convection coefficient, besth, is printed to the screen at the end of the run. In addition, a plot of the residual vs. h is provided. Make sure that you actually found the minimum with your chosen range:

h Residual Plot

Repeat this process for all four natural convection experimental data sets and record the best fit h for each one.


Last Modified by Bob Cochran, on September 29, 2017