High-Efficient Micro Reacting Pipe with 3D Internal Structure: Design, Flow Simulation, and Metal Additive Manufacturing
Round 1
Reviewer 1 Report
The paper describes an experimental and simulation investigation of micropipe for mixing reacting. The pipe exploiting the advantages of laser powder bed fusion process.
The paper must be improved in several sections and therefore it needs major revisions before to be acceptable for publication.
First of all, the language needs extensive editing with the aim to correct grammatical error, typing errors (e.g. page 3 line 98 “mental” should be “metal”), improve the readability (some sentence is difficult to read) and the clarity.
The review section must include more details. Clarify what AM technology has been used to produce this kind of pipes in all reviewed previous work, what are the limitations. In the paper it seems like the design of the pipe to be fabricated was easy. A review section should be introduced on the design for L-PBF including a review of general methodology such as Crystals 2020, 10(3), 161; https://doi.org/10.3390/cryst10030161 or specific works also including other applications such as J. Turbomach. Feb 2018, https://doi.org/10.1115/1.4038180, J. Mech. Des. Nov 2015 https://doi.org/10.1115/1.4031071, https://doi.org/10.1016/j.ijheatmasstransfer.2018.11.126
The novelty of the paper, also respect to other works of the same authors, must be better highlighted.
The effect of the process features on the final performance of the pipe should be discussed, like presence of residual powder inside the pipe, roughness, incorrect shape due to design limitations. It looks like in Figure 13 the pipe on the bottom is not well formed. Is that accounted in the simulation?
Please refers to the AM process with the standard names: SLM is Laser powder bed fusion (L-PBF), SLA is sterilithography.
Please use international unit of measure. Litre is l (lower case letter).
The readability of the figure and their legend must be improved. E.g In Figure 13 the diameter of the different pipes is not indicated.
Why the investigation has been performed using Inconel and 316L?
Please add a brief description of the L-PBF.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This paper discussed the fabrication of micro reacting pipes with a 3D inner structure using selective laser melting additive manufacturing process. The SLM process has very unique features to build components that are very difficult to make by the traditional manufacturing processes, and this paper demonstrated the advantages of SLM in building micro reacting pipes. The paper investigated many aspects of these printed parts, such as corrosion resistance, mixing efficiency, and largely, CFD modeling. It is an interesting study, but the writing significantly damaged the smooth understanding of the paper. For example, there are many extremely long sentences in the manuscript. Such sentences didn’t improve the quality but make readers very difficult to understand. Considering using simple sentences as long as the information is revealed. The writing must be improved significantly to make most parts clear. The reviewer suggests a major revision of the manuscript. Please address the following issues.
(1) Line 20: many post-processing processes. In this..
(2) Line 44: do you mean R&D period?
(3) Line 44: …fields. For instance ….
(4) Line 44: Awkward and difficult to understand: …chemical and pharmaceutical fields, for instance, Luong Jim et al. who have effective management of extra-column effect and the capability to perform post-columm backflushing were achieved via 3D-printed two-stage microreactor and other electronically controlled pneumatic switching device.
(5) Line 51: Awkward and difficult to understand: The critical dimension of the micro reacting pipe is only in the order of micron to millimeter, which greatly increases the influence of the wall viscosity force on fluid, which makes the flow pattern in the channel of the micro reacting pipe mostly presented as laminar flow.
(6) Line 56: What does this mean: 1×10-10-1×10-9m2/s?
(7) Line 58: …improve the production efficiency and practical value of the micro reacting pipe.
(8) Line 59: One of the effective methods
(9) Line 60: directly. For instance…
(10) Line 67: Awkward and difficult to understand: For instance, using lithography, micro-molding and bonding techniques to build Polydimethylsiloxane micromixer [8]or using a standard wet etching technique to fabricate the designed channel and the low-temperature hot-pressing technique was utilized for glass–glass chip bonding to produce the designed micromixer, but which method can only make 2D shape [9].
(11) Line 71: manufacture
(12) Line 71: Too long and very difficult to understand: There are some other methods to manufact 3D shape micromixer, such as forming a three-dimensional (3-D) passive micromixer with propeller blades fabricated by two-photon polymerization (TPP)[10] which need a long time for that printed 3D object is fixed so the process is cumbersome and the high-precision equipment is expensive, creating 3D-microfluidic reactor in Low Temperature Cofiring Ceramic (LTCC)[11] whose thermal conductivity is poor and has difficulty in controlling sintering shrinkage, benting straight tubes of copper into coil considering the circularity as micromixer [12], which causes the internal structure too simple to produce turbulence to mixing solution efficiently.
(13) Line 90: change additive manufacturing to AM
(14) Line 97: there are research which is based on …
(15) Line 98: change mental to metal
(16) Line 99: [22]. Urvashi …
(17) Line 102: Awkward: and materials to improve the hydrogen production performance of microreactors[23], but which are also constrained by the shape of molding or need other part to make a laminated plate microreactor, has relatively complex processing steps.
(18) Line 108: Too long and difficult to understand: There are some scholars have applied CFD to estimate the insight of microreactor, such as Harrson S. et al. who have discussed computational methodology for the development of microdevices and microreactors with ANSYS CFX [24], Moreover, the chemical experiment used the Villermaux-Dushman parallel competition reaction system, which uses the concentration of I3 in the outflowed solution as a probe to evaluate mixing efficiency.
(19) Line 126: powders are shown in Fig. 1b-c.
(20) Line 127” is the chemical composition in “wt. %”?
(21) In Equipment and materials, briefly talk about the principle of SLM, one sentence is good.
(22) Line 134: pipe was obtained in this paper.
(23) Line 142: Design of micro reacting pipe
(24) Line 148: Awkward: At the same time, because of the process constraints of SLM, designer should pay attention to forming the micro reacting pipe in an axis vertical to the substrate, and the angle between the suspended structure and the wall in the channel should be greater than 45 ° for preventing from building support inside the channel which cannot be removed after forming [25]. So, the first design principle is obtained: the angle of inclination of the internal structure is more than or equal to 45 °.
(25) Line 167: cite references about the equations
(26) Line 177: Firstly, the mesh file of the model was constructed
(27) Line 230: for forming the micro reacting pipe
(28) Line 243: and the molding parameters obtained in the previous paper: please cite the paper
(29) Line 252: Awkward: The compression resistance test in this study was a boost test, and the test pressure was dynamic pressure, which the horizontal flow pump was used to inject water into the formed micro reacting pipe, and the output flow rate of the pump was continuously increased, so that the pressure was gradually increased.
(30) Line 314: cite reference for the equation
(31) Line 377: did you do experiments to validate the CFD simulation results?
(32) Line 383: depends
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The paper needs English editing that improves the grammar and the readability of the paper.
Some examples:
Line 98 "needs" and not "need"
line 101 "cannot" and not "can not"
line 186 "was" and not were
line 378 "designed" and not "de-signed"
Author Response
Dear Professor,
Thank you very much for your comments and suggestions.
We have improved the grammar and the readability of the paper.
Yours Sincerely
Dr. Di Wang
Reviewer 2 Report
Thanks.
Author Response
Dear Professor,
Thank you very much for your comments and suggestions.
We have improved the grammar and the readability of the paper again.
Yours Sincerely
Dr. Di Wang
