ECAR 131 Verification Problems
Overview
ECAR 131 is an INL internal report describing a set of simulations used to verify the quality of Abaqus solutions. The problems described here are taken from ECAR 131. The analytic solutions for these problems come from Incropera and DeWitt (2001).
An accuracy tolerance of 3% is used in ECAR 131.
Nomenclature
Table 1: Symbols and their meanings.
| Symbol | Definition |
|---|---|
| thermal conductivity | |
| specific heat | |
| density | |
| heat transfer coefficient | |
| length | |
| radius | |
| Cartesian coordinate | |
| radial coordinate | |
| temperature | |
| heat flux | |
| mass flow rate | |
| time | |
| emissivity | |
| Stefan-Boltzmann constant | |
| relative error | |
| thermal diffusivity | |
| Biot number | |
| Fourier number | |
| Stanton number |
Plane Wall with Convection (Problem #1)
This problem is a wall with one surface insulated and the other surface having a convection boundary condition. The insulated surface is at , and the surface with the convection boundary condition is at . The parameters for this problem are in Table 2.
Table 2: Parameters for plane wall problem.
| Symbol | Value |
|---|---|
| 0.45 W/in/K | |
| 4.2E5 J/kg/K | |
| 2.7E-5 kg/in | |
| 0.375 W/in/K | |
| 1.2 in | |
| 4 C (fluid temperature) | |
| 60 C | |
| 0.8603 rad | |
| 1.1191 |
The analytic solution is given as
At = 90 seconds, the temperature at the insulated wall is 13.997 C, and the temperature at the other wall is 10.52 C.
Table 3: Results for plane wall with convection.
| Wall | Analytic | Bison | Error |
|---|---|---|---|
| Insulated | 13.997 C | 14.151 C | 1.10% |
| Convection | 10.52 C | 10.620 C | 0.950% |
Plane Wall with Convection, 2D (Problem #2)
The problem is the same as the previous one but in 2D instead of 3D.
At = 90 seconds, the temperature at the insulated wall is 13.997 C, and the temperature at the other wall is 10.52 C.
Table 4: Results for 2D plane wall with convection.
| Wall | Analytic | Bison | Error |
|---|---|---|---|
| Insulated | 13.997 C | 14.151 C | 1.10% |
| Convection | 10.52 C | 10.620 C | 0.950% |
Cylinder with Convection (Problem #3)
This problem is a cylinder with a convection boundary condition on the radial surface.
The parameters are the same as for Plane Wall with Convection (Problem #1) except that is replaced with = 0.6 in.
The analytic solution is given as where is the Bessel function of the first kind, with = 0.
At = 18 seconds, the temperature at the wall is 12.521 C, and the temperature at the center of the cylinder is 14.777 C.
Table 5: Results for cylinder with convection.
| Location | Analytic | Bison | Error |
|---|---|---|---|
| Wall | 12.521 C | 12.753 C | 1.85% |
| Center | 14.777 C | 15.074 C | 2.01% |
Plane Wall with Internal Heat Generation (Problem #4)
This problem is similar to Plane Wall with Convection (Problem #1). However, instead of a convection boundary condition at one wall, the temperature at that wall is fixed, = 4 C. Also, the wall has internal heat generation = 6.1 W/in.
The analytic solution is given as
Table 6: Results for plane wall with heat generation.
| Coordinate | Analytic | Bison | Error |
|---|---|---|---|
| 0.0 | 13.76 C | 13.76 C | 0% |
| 0.3 | 13.15 C | 13.15 C | 0% |
| 0.6 | 11.32 C | 11.32 C | 0% |
| 0.9 | 8.27 C | 8.27 C | 0% |
| 1.2 | 4.00 C | 4.00 C | 0% |
Plane Wall with Internal Heat Generation, 2D (Problem #5)
This problem is the same as the previous one but in 2D instead of 3D.
The analytic solution is given as
Table 7: Results for plane wall with heat generation.
| Coordinate | Analytic | Bison | Error |
|---|---|---|---|
| 0.0 | 13.76 C | 13.76 C | 0% |
| 0.3 | 13.15 C | 13.15 C | 0% |
| 0.6 | 11.32 C | 11.32 C | 0% |
| 0.9 | 8.27 C | 8.27 C | 0% |
| 1.2 | 4.00 C | 4.00 C | 0% |
Semi-infinite Plate with Heat Flux (Problem #6)
The parameters are the same as for Plane Wall with Convection (Problem #1) except that the heat flux at the surface is given as = 7.3 W/m.
The analytic solution is given as
At = 90 seconds, the temperature at the surface is 94.593 C, and the temperature at a depth of 1 in is 80.764 C.
Table 8: Results for semi-infinite plate with heat flux.
| Location | Analytic | Bison | Error |
|---|---|---|---|
| Surface | 94.593 C | 94.497 C | -0.101% |
| Depth 1 in. | 80.764 C | 80.729 C | -0.0431% |
Radiation between Parallel Plates (Problem #7)
The problem as defined in ECAR 131 uses shell elements. We instead use 2D elements.
This problem is one of radiation heat transfer between parallel plates. The temperature at one boundary is 278 K, and at the other boundary the temperature is 333 K. The emissivities of the two boundaries are 0.8 and 0.9. The value of the Stefan-Boltzmann constant, , is 5.670374e-8 W/m/K.
The analytic solution for the flux is given as
Table 9: Radiation flux between parallel plates.
| Analytic | Bison | Error |
|---|---|---|
| -263.44 W/m | -261.25 W/m | -0.83% |
Radiation between Concentric Cylinders (Problem #8)
This problem is conceptually similar to the previous problem. We use 2D elements instead of shells, as were used in ECAR 131.
The inner radius, , is 0.5 in. The outer radius, , is 0.525 in.
The analytic solution for the flux is
The analytic solution for the flux is
Table 10: Radiation flux between concentric cylinders.
| Flux | Analytic | Bison | Error |
|---|---|---|---|
| -264.47 W/m | -264.37 W/m | -0.037% | |
| 251.87 W/m | 251.78 W/m | -0.036% |
Convective Heat Transfer to a Fluid Flowing in a Circular Tube (Problem #9)
This problem is heat transfer to a fluid in a circular tube. The temperature at the surface of the tube is fixed, = 50 C. The parameters for this problem are in Table 11.
Table 11: Parameters for convective heat transfer to a fluid.
| Symbol | Value |
|---|---|
| 189 W/in/K | |
| 4.2E5 J/kg/K | |
| 29 in | |
| 4.5E-4 kg/in/s | |
| 120 in | |
| 55.55 C | |
| 1.0 | |
| 2/ |
The analytic solution for the average fluid temperature is given as
Table 12: Results for convective heat transfer to a moving fluid.
| Position | Analytic | Bison | Error |
|---|---|---|---|
| 0.0 | 55.55 C | 55.55 C | 0.00% |
| 6.0 | 53.669 C | 54.085 C | 0.78% |
| 12.0 | 52.426 C | 52.815 C | 0.74% |
| 18.0 | 51.604 C | 51.848 C | 0.47% |
| 24.0 | 51.06 C | 51.172 C | 0.22% |
| 30.0 | 50.701 C | 50.730 C | 0.057% |
| 42.0 | 50.306 C | 50.275 C | 0.063% |
| 60.0 | 50.089 C | 50.062 C | 0.053% |
| 90.0 | 50.011 C | 50.005 C | 0.012% |
| 120.0 | 50.001 C | 50.001 C | 0.0011% |
Plane Wall with Radiative Boundary (Problem #10)
This problem is a wall with one surface insulated and the other surface with a radiative boundary condition. The insulated surface is at , and the surface with the convection boundary condition is at . The parameters for this problem are in Table 13.
Table 13: Parameters for plane wall problem with radiative boundary condition.
| Symbol | Value |
|---|---|
| 45 W/in/K | |
| 4.2E3 J/kg/K | |
| 2.7E-5 kg/in | |
| 1.0 | |
| 1.2 in | |
| 0 K (ambient temperature) | |
| 333.15 K | |
| 3.658E-11 W/in/K | |
| 1.1191 |
The analytic solution is given as
At = 90 seconds, the temperature at the wall with the radiative boundary condition is 215.713 K.
Table 14: Results for plane wall with radiative boundary condition.
| Analytic | Bison | Error |
|---|---|---|
| 215.713 K | 216.217 K | 0.234% |
Conduction between Parallel Plates (Problem #11)
The problem is conceptually similar to Problem #7 but involves conductive heat transfer between the plates.
The distance between the plates is 1 in. The thermal conductivity, , of the gap is 0.1 W/in/K. This gives W/in/K.
The analytic solution for the flux is
Table 15: Conduction across a Gap between Two Parallel Plates
| Analytic | Bison | Error |
|---|---|---|
| -8525 W/m | -8524.98 W/m | -0.00026% |
Plane Wall with Heat Generation and Phase Change (Problem #12)
This problem is a wall with both surfaces insulated. The wall has changing heat capacity due to phase change. The left surface is at , and the right surface . Also, the wall has internal heat generation = 37.8 W/in. The parameters for this problem are in Table 16.
Table 16: Parameters for plane wall problem with heat generation and phase change.
| Symbol | Value |
|---|---|
| 100 W/in/K | |
| 4.2E5 J/kg/K | |
| 2.7E-5 kg/in | |
| 3.78E7 J/kg (latent heat) | |
| 1.2 in | |
| 60 C | |
| 400 K (solidus temperature) | |
| 410 K (liquidus temperature) | |
| = 3.78E6 J/kg/K (latent heat capacity) |
The time to reach solidus temperature is
The time to reach liquidus temperature is
= 30 s, and = 60 s.
The temperature at the wall at = 50 s is
This gives = 406.667 K.
Table 17: Results for plane wall with heat generation and phase change.
| Analytic | Bison | Error |
|---|---|---|
| 406.667 K | 406.667 K | 0% |
References
- F. P. Incropera and D. P. DeWitt.
Fundamentals of Heat and Mass Transfer.
Wiley, New York, fifth edition, 2001.[BibTeX]