Study on Comprehensive Performance of Three-Dimensional Tube Applied to Gas–Solid Two-Phase Flow Environment

Round 1

Reviewer 1 Report

The subject of the work is interesting, but the editing side of the manuscript is very poor.

As an example, I am giving a few comments:

1. It will be easier for the reader if the same symbols for the given tubes are used in all figures.
2. It seems that the charts will be more legible if the legends do not include additional "Fitting curve", the more so that some figures do not contain them (eg Figs. 5 and 8).
3. If the heat transfer parameters are determined only outside the tube, maybe it is not necessary to use the index "o"?
4. The Nusselt number for a smooth tube is referred to once as Nu_o-s and other times as Nu’_o, it might be worth standardizing that. The same goes for f_o-s and f’_o.
5. The dimensions are not visible in Fig. 2, maybe it is also worth adding a section on which the spacing of the tube bundles will be shown.
6. There is a list of symbols at work, but it would be easier to read the text if the new symbols had their description in the text.
7. There is no mention in the manuscript about tables 1 and 2.
8. Erroneous data are presented on the horizontal axis in Fig. 5.
9. What is v? Flow rate or flow velocity?
10. If V_o has a unit of m³/s, F_o – m² and v_o – m/s, why is there 3600 in formula 5?
11. In many cases, there are dimensional quantities on the figure axes but units are missing.
12. Line 71 – there is information that some dust was added to the air to simulate the working fluid of the waste power plant, but there is no information about the type of this dust and how much was delivered.
13. Line 264 – it is f_o-Nu_o but it should be Nu_o-f_o.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Compact heat exchangers have been used in industry for more than 60 years.
The manufacturers of this type of exchangers already provide the working parameters in detail.
The TEMA regulation also dictates the operating principles.
This work attempts to characterize the heat exchange, but does not provide significant novelties.

I think that error propagation analysis is very basic.

It is necessary, in addition to the general scientific content of the article, to improve the formal questions. Be careful to submit the manuscript, this requires a thorough review by the authors. For example, in line 75 -> Pressure transmitters, line 93 -> Processing, etc ...

On the other hand, for the measurement of transport properties, a suitable test bench is needed. Only a schematic figure is shown. Photographs of the equipment and sensors used would be needed.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

How the relative errors were determined in case of direct measurement, for example the value 0.077%?

Some minor mistakes and errors are:

line 75: should be 4. pressure transmitters  instead of 4. ressure Transmitters

Figure 2: dimensions are hard to read

line 104: "o" should be in subscript closer to alpha letter

line 120: should be Fanning

line 207 -this sentence seems incomplete

lines 271, 274, 275, 300, 303, 310, 321 - why FIG. not Fig.?

List of symbols: δ is listed twice in Nomenclature and Greek symbols sections.

References contain inconsistencies and should be carefully reviewed

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Many thanks to the authors. I think that with these modifications the article is more complete and understandable