Effects of Reynolds Number on the Overall Characteristics of Flow and Heat Transfer in the Long Micro-Tube with Dimples
Round 1
Reviewer 1 Report
The following comments should be considered to revise the manuscript.
1. Please, rewrite the abstract as introduction, problem statement, methodology, results, and conclusion.?
2. The novelty of the work must be clearly addressed and discussed
3. compare your research with existing research findings and highlight novelty.
4. Please clarify how references were selected?
5. Introduction section must be written on more quality way, reference should be reviewed with the main results and contribution to the research gap.
6. More up-to-date references should be addressed to enrich the introduction section, such as: Thermodynamic characteristics of a novel combination of three-start twisted tube and oval dimples. Case Studies in Thermal Engineering, 2022(37) 102284, and so on.
7. Please provide more detailed information about the geometrical parameters, such as the parameters of the dimples, the arrangement of the dimples, ....
8. What’s the mean of p1, p2, ..., p5 in Figure 2?
9. Are there fins around the tube for the numerical model? There are fins for the experimental setup.
10. Please clearly indicate the fluid used for the study.
11. For Figure 8 about the pressure drop, the author stated that ‘The error is mainly caused by the wall temperature may be different between numerical simulation and experimental measurement.’ Please explain how the temperature affect the pressure drop.
12. Explain the ‘average Reynolds number’ in Figure 17.
13. Deep and detailed discussion about the results are needed.
14. English language should be carefully checked and carefully check paper for language typos.
15. The conclusion part should be concise with the major conclusions, and quantify the conclusion.
Author Response
The response to reviewer can be seen in the file.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The research is focused on a long micro-tube with dimples. A CFD model study on the influence of Reynolds number on the overall characteristics of flow and heat transfer was carried out.
The manuscript is well organized, fits the scope of the well-known high level journal Processes and the topic is very important. The quality of the conducted study is high. The presented results of the performed modeling work have scientific and practical meaning. The description of models, research background are solid. For the CFD work, model descriptions, boundary conditions, mesh sensitivity verifications, validation and results are presented in a reasonable way except the description of turbulence model. Overall it is a nice work.
My concerns and comments:
1. The two word validation and verification should be distinguished. Verification means ‘‘solve the equations right’’ and typically used for mesh independent tests. Validation means ‘‘solve the right equations’’ and typically used for comparison with experiment results. Ref from H.K. Versteeg and W. Malalasekera: An Introduction to Computational Fluid Dynamics: The Finite Volume Method, p. 307.
2. Could the low Reynolds number cases be laminar flow? Could k-w turbulence model be suitable for laminar flows? Besides the model description should be given.
3. The fluid properties (could be air?) may be given at different temperatures.
4. The authors should supply 1 reference where the FLUENT software is presented/validated. For example website, official user guide.
5. s is commonly used as surface tension of fluid. Please use some other symbol to represent the area ratio.
6. Figure 10,12, the bars for length scale of tube should be moved to the lower part of the corresponding figure.
7. References of recent years and high quality journals might be referred. The format of reference is not correct.
Author Response
The response to reviewer can be seen in the file.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
the revised manuscript can be considered for acceptance.
