COP and Superheat - does is it help?

[desA]

desA
One sincerely doubts that your simulation would require the use of Eulerian flows modeled on a tetrahedral mesh. FE/FD methods are well known - as is Newton Raphson convergence techniques. (Not always the most stable, mind you - fairly dated by now). That is, unless you're attempting to accurately model two phase flow evaporation/condensation regimes. You may want to save some level of energy, by reading up varous legacy books on the topic (e.g Collier/Thome & Thomes' later works).

Chef
You asked me to reveal a lot more about the software platform - so I did.

In a coiled capillary tube one cannot use cubic meshes (they dont go around bends) and so tetrahedral is the best choice. For each mesh one solves the conservation of mass plus the momentum equations. Now add to that the energy equation and Oh gosh, bless my soul, it is called the Eulerian formulation.

And strangely enough as Eulerian maths involves derivatives the Newton Raphson is the recommended first approach to a solution. And this is exactly what I do in my cap tube and evaporator.

Come on DesA - any first year student would know that. That would of course be in an engineering discipline and not psychotic behaviour

So if you ask a question - read and respect the answer.

So now that you are done throwing your toys out of the pram maybe, as you say old boy, we can back to the task at hand.

Dear Chef,

Many cap tube simulators will tend to use a 1D model. Refer here to the Indian lecture notes you mentioned some years ago. With the length-to-diameter ratio for a cap tube being so large, the radial/centrifical effects would/could generally be neglected. The numeric scheme for such 1D model could use a number of discretisation approaches - some more stable than others - 1st order, 2nd order, etc. A description of one approach is offered on the Technisolve website - that program offers 3 different solutions to the cap tube length. Without being able to dissect your methodology, I would have to take your word that you have a new, novel approach to solving the matter.

The reference to Eulerian flows & tetrahedral meshes would, in most engineering academic circles, infer the use of a CFD approach to problem solution (FV/FEM/FD...). Given the current lack of theoretical knowledge in the two-phase area, using such an elaborate approach would have been both overkill, & in all likelihood, very inaccurate. Still a lot to be learned in this area. Packages like Elmer may be of use to you here. The name Euler has been attached to many, many areas of maths/science.

I will stand my ground academically against you, as I've been in the simulation & heat-transfer arena all my working career. I am prepared to argue all the way through defence of the Navier Stokes & Energy equation sets, if needs be. This is my stock-in-trade, if you will.

My preferred approach, however, is to engage in a healthy debate, via this forum & the wonderfully helpful contributors & colleagues. We can all stand to learn a huge amount from each other, even if we don't each, individually have each & every answer. The collective approach is both fun & informative - we all learn a huge amount. In many aspects of this business, much can be said about it being part art-form, experience-based, & academic.

On a public-domain web-forum, the 'shoot the messenger' approach, generally leads to tears & discomfort for the other forum members reading the 'kill-shots' & 'return-shots'. Perhaps you would, in future, be so kind as to take this kind of attack offline via PM? I'd certainly be most happy to discuss further with you off-line.

Should we agree to disagree & get back to the topic at hand? I'll bet that we are both spoiling the thread by our bison head-butting approach.

Take care,
desA