Entropy Generation Results of Convenience But without Purposeful Analysis and Due Comprehension - Guidelines for Authors

There is a growing trend in recently-submitted manuscripts and publications to present calculated results of entropy generation, also known as entropy production, as field quantities in a system or device control volume, based on prior calculation of velocity and temperature fields, frequently using CFD numerical methods. On occasions, such results may appear to be very interesting and elaborate intellectual exercises, yet are without purposeful analysis and meaningful objectives, without some discovery or new method, and therefore without due comprehension. Often, such entropy generation results are presented separate from, and without due analysis and correlation with, the related flow and heat transfer results, the latter usually published before. The entropy generation results are often presented “as is”, with almost trivial analysis and conclusions, and with little, if any, purpose and objective. Stating the obvious, based on the calculated outcome, where and in what region the entropy generation is maximum and higher, and where it is lower and minimum, is a self-evident observation and does not provide any method for design optimization, and usually no parametric study and results are presented to generate useful data for future analysis and optimization. It appears that such work is performed as a matter of convenience, since the flow and heat transfer results were already performed in related prior work. Therefore, such manuscripts become more opportunistic than purposeful, and thus have little value if any at all. Such results may be easily performed by specialists in CFD, but non-experts in Thermodynamics, and without due comprehension of the meaning of entropy generation as a critical concept of the Second Law of Thermodynamics. It would be similar if CFD results are conveniently performed without due analysis by non-experts in fluid mechanics and heat transfer, just because of the opportunity and availability of powerful computational methods and software. In some cases, the energy equation used for entropy generation is simplified and does not contain all potentially relevant terms. For example, the energy dissipation term is often neglected for velocity field calculation, but it may be important for the proper entropy generation calculation. Such, and other, simplifications should be explicitly stated and valid justifications provided. Given that validation of the numerical methods is often limited in simpler geometry and prior flow and heat transfer result, and, usually, no specific validation were given for the entropy generation results, the former does not necessarily imply the latter. The validity of entropy generation results have to be justified in addition to, and independently from, the validity of the related flow and heat transfer results. Self-critical analysis of the simplifications and limitations of the methodology and calculation methods should be presented, along with proper uncertainty error analysis and validation of the obtained entropy generation results. Furthermore, the entropy generation results could and should be correlated with related flow and heat transfer results, and presented together to synergistically enhance the integral analysis, and not be separated and presented as independent and not correlated results. The check-and-balance of the