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All models start from simple schematic models. The simple model has as few nodes as possible in order to capture important features and gain insight. Complexity is added to the models until the desired refinement and accuracy is obtained. The final model may have only a dozen nodes or it may have, in the case of some finite element models, 100’s of thousands of nodes. The goal is to reach answers quickly in a cost-effective manner while having assurance of the validity of the results. A series of simple models gives one assurance that the answer is right. An analyst who plunges into a large model with all the incumbent complexity tends to become overwhelmed by the logistics and manipulations and lose sight of what are reasonable results. A legacy of simple models provides a reality check.

The level of complexity required for a particular model is determined by the desired results. If, for example, one needs to size a fan for an electronics box, modeling individual components on each board is unnecessary. Overall board temperatures and powers will suffice, however it maybe necessary to know component temperatures at a later stage in the design process. The analysis is taken to a level that provides an answer that is sufficient, this reduces time and cost.

Engineering judgment must be made in each case to decide what level of complexity is required at each step in the design process. In most cases modeling complexity and refinement proceeds as the design becomes finalized. A possible exception occurs when CAD geometry is used. Often the thermal analyst is handed finalized CAD geometry that is overly detailed for thermal analysis. One can simplify the geometry (this requires special skills) or one can create new geometry. However, it may be cost effective to take the geometry as is, mesh it, and perform the analysis. Simplification will almost always be required when radiation is involved. Current Monte Carlo radiation programs take unduly long when a large number of surfaces are involved.

Quality Assurance
All models undergo rigorous quality checking; each model is peer reviewed by one or more consultant using standard quality procedures.

Reports
Introduction - The report will contain an introduction explaining the nature of the devices and processes being modeled and the goals of the consulting project. It will also outline the analysis methods used.

Body - The body of the report will contain elaboration of devices and processes and modeling details. It will state assumptions, boundary conditions, materials, etc. Results will be stated here with any graphs and post-processing pictures. All assumptions are enumerated and caveats are discussed.

Conclusion and Recommendations - General conclusions from analysis results as well as recommendations for further analysis or design changes as required.

Appendices – material that is important but need not be included in the body of the report such as custom code used in the model or derivation of formulas.

References - References to textbooks, papers, other reports.



He completed thermal study of rugged compact PC for military applications. This involved computer models as well as thermal and fluid measurements to confirm computer models. This device involved radiative heat transfer, heat pipes, a fan, natural convection.He completed a thermal and cooling effectiveness assesment of compact avionics in a spy plane. This involved temperature and air flow measurements and heat budget HVAC calculations for the entire plane. He performed Finite Element Model for compact cross-flow heat exchanger that involved novel methods of applying fin equations. The analysis was transient and included pulsed air flow.