Transient Heat Conduction in Cylindrical Geometry
- November 18, 2014
- 2 replies
- 9356 views
I tried converting a 7yr old MathCAD 11 spreadsheet to MathCAD 14 (then to 15) to solve a transient Heat Conduction Equation in Cylindrical Geometry.
I used the old spreadsheet (attached) to evaluate at heatup of electrical cables from an external fire source about 6-7 years ago. The standard tools (Pdesolve, CreteMesh,..) don't seem to work in later versions of MathCAD.
The current problem to be simulated is localized heat-up of a Tin foil via passing electrical current through a localized area with effective Radius Ro.
The problem involves just one function: Ttin(r,t) - temperature as a function of radius and time, one initial condition, boundary conditions near the origin and farther away, and a time varying heat input source concentrated within Ro.
The Pdesolve (....) block does not appear to generate an error message. I've tried all four of the curve-fitting solver options and cannot generate the mesh needed to generate solution plots. The Error Message is: "The number of functions must match the number of initial conditions." When I search in the MathCAD help -- there isn't much there of value.
The trace error option just refers me back to the Pdesolve block.
I also tried (in lieu of generating contour or patchplots), generating slices representing transient temperature distributions at different radial locations.
This gives the Error Messge: "All evaluations resulted in either an error or a complex result."
-- So before I dig out my old MathCAD 11 CD to get things working -- does anybody have a clue what is going on and why Pdesolve, CreateMesh seem to want more initial conditions and cannot process what should be a rather straight forward solution??
Thanks in advance!
John Bickel

