Optimization of Screw Mixer to Improve Drying Performance of Livestock Manure Dryer Using CFD Analysis
Round 1
Reviewer 1 Report
Review of the manuscript entitled: Optimization of screw mixer to improve drying performance of livestock manure dryer using CFD analysis
Dryers optimization is an interesting and relatively demanding case for modeling. On the other hand, CFD simulation, it's an up-to-date subject presented in a lot of papers. The same situation concern experimental comparing simulation results. However, the important difference is the experimental measurement to visualization. Generally, the manuscript is written on the average level. However, contains elements that need to extend and explain.
Below are the main elements:
1. If the authors declared in the title optimization, the objective function should be provided, explained and discussed. The same situation concern optimization criteria, their scales, etc. Generally, all optimization methodology elements are missed.
2. Details of the mesh quality testing (quality parameters) should be provided. Especially for the transient flow case.
3. Initial conditions and simplifications of the case should be detailed and (the most important) justified.
4. The authors consider the SST turbulence model. What are the advantages of adopting this approach over others in this case? How will this affect the results? The authors should provide more details on this also on the basis of literature research and justify their own choice in the view of the simulated case. The same remark concerned with the particle model approach.
5. Details about convergence testing should be provided.
6. The scale-up for this case to other similar dryers should be provided and discussed.
7. The most important element. What about comparing CFD and experimental results? Some discussion is necessary, especially in the main subject of simulation, like the motion behavior of dried material (in this case: livestock manure) as well as temperature distribution and moisture content (in general: important parameters of heat and mass transfer for drying process)
Also,
8. Fig 7 is too small and not clearly presented. If the authors present some contour plot some discussion is necessary also.
In summary: I recommend a major revision of the manuscript. I hope that the manuscript will be improved and published because the subject is concerned with the CFD approach. I hope, that the manuscript will interesting for potential readers.
Author Response
Thanks for the kindness favor.
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 2 Report
In my opinion, it would be better to take into account following recommendations:
1 it is necessary to compare calculation results with experimental data to validate the described CFD model;
2 it is interesting to include some parametric analysis of screw dryer by using obtained CFD model
At present time CFD models are widely used for a flow calculation inside of different units. It is one of the best tools to predict influences of different parameters on the object of the research. At same times, every CFD model has a lot of parameters which must be chosen before calculation and has high influence on obtained results’ accuracy. This paper is dedicated to the CFD model of the screw dryer. Therefore, this paper is interesting and quite clear. I think it can published in present form.
But the accuracy of calculation result should be checked by comparing with experimental data. It is necessary due to I pointed above. I think it was done, but was not included to the paper. In other hand, the CFD model is only tool for the calculations, which are used for the parametric analysis. Result of this analysis are more interesting in general, therefore my recommendation is to pay more attention to the discus of obtained results and parametric analysis.
Author Response
Thanks for the kindness favor.
Please see the attachment.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
Re-review of the manuscript entitled: Optimization of screw mixer to improve drying performance of livestock manure dryer using CFD analysis
The authors prepared answers, provide adequate corrections, and improve the manuscript. The re-reviewed paper has average novelty aspects. The paper has a practical aspect also.
In summary: in view of responses and prepared corrections, I recommend accepting the manuscript in the present form.
