Investigation of Flow and Heat Transfer Performance of Double-Layer Pin-Fin Manifold Microchannel Heat Sinks

Round 1

Reviewer 1 Report

Ms. Ref. No.: Water- 1927126

Title: Investigation of Flow and Heat Transfer Performance of Double-Layer Pin-Fin Manifold Microchannel Heat Sinks

In this paper, the performance of the MMC, a double-layer pin-fin MMC structure was designed. Using deionized water as a working liquid, the flow and heat transfer characteristics were numerically investigated. Compared with the single-layer MMC, the temperature uniformity is better, the pressure drop is lower, and the comprehensive performance is improved at the cost of slightly larger thermal resistance for the double-layer MMC. The geometric effects on the flow and heat transfer characteristics were also analyzed. The results show that among the pin-fin structures with round, diamond-shaped and rectangular cross-sections, the round pin-fins demonstrate the best comprehensive performance and minimal thermal resistance. The analyses themselves are sound and I believe the results of their work. The data are well organized by the authors. I, therefore, recommend this paper be published in the Water Journal after the authors address the following comments.

·         Review English grammar as there are mistakes throughout the text. This article should be completely rewritten.

For example:

Abstract:

microchannel structure-> microchannel structures

as working liquid-> as a working liquid

the minimal thermal-> minimal thermal

Introduction:

circuit doubles-> circuit double

chip's performance->the chip's performance

the minimal pressure drop-> minimal pressure drop

the angle of-> an angle of

demonstrates the minimal pressure drop-> demonstrates a minimal pressure drop

compares with-> compared with

layers affects the flow-> layers affect the flow

perturbation structure-> the perturbation structure

Recently, MMC heat sink-> Recently, the MMC heat sink

the liquid turns direction-> the liquid turns in direction

·         The abstract must be revised.

·         The quality of figure 4 must be better. Also for other figures.

·         The physical explanation of figures 7 and 8 is limited. Please explain more.

·         Fig 8-a, 9-a, 10 a and c must be edited. The graphs are very close together.

·         More physical insight into the discussion section is needed.

·         What is time used for convergence?

·         What is the criterion of convergence?

·         Where is the mesh?!! The authors must show the mesh and quality of the mesh.

·         The literature section must be improved with more advanced articles and clearly why your present study is different, better to explain novelty.

·         The author must improve the introduction with more advanced applications. Also, the author could find new references for the literature review. For example:

AIChE Journal, 61(6), 1912-1924, Chemical Engineering Journal, 356, 492-505,  International Journal of Heat and Mass Transfer, 187, 122500,  Analytica chimica acta, 838, 64-75, Chemical Engineering Journal, 328, 1075-1086.

In conclusion, this paper might be made suitable for publication in this Journal if the as-mentioned comments are clarified. These constitute a major revision of it.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

A numerical work on a double-layer pin-fin MMC structure. The literature reviewed is relevant but not up to date. Limited attempt to critically discuss the literature reviewed and highlight the gaps in current literature. 

The methodology is aligned with objectives. The methodology and technique chosen are appropriate for the nature of the project.  Most of its components are described. There are some attempts at justification for decisions taken. There are some attempts at evaluating assumptions made. Any limitations to the methodology are mentioned.

Results are displayed using appropriate visuals. Analysis of results is consistent with objectives. There are some attempts to interpret and evaluate results using analysis of data and synthesis of information. Limitations of the results are discussed. Error analysis is not attempted.

Conclusion summarizes research findings, aligns with research objectives and outlines the significance of the work done in a range of contexts. Future work is not identified or not relevant. 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments

• Abstract

• Would be good to specify how the heat plates were “numerically investigated”; something like “numerically investigated using computational fluid dynamics” or “numerically investigated using ANSYS Fluent”

• Introduction

• How is “enhanced heat transfer coefficient” defined in the statement that “the enhanced heat transfer coefficient reaches 1.28” statement?

• Methodology

• Grid independence verification and simulation method validation section

• In Figure 4, how were the solid lines obtained? Are these based on theory?

• Need to provide more details on the validation comparison to the experiment work of Drummond

• Same geometry (single-layer MMC?, double-layer MMC?)?, same flow?

• Drummon was a two-phase cooling study, but the presented work appears to be only single-phase; Is the comparison only in the single-phase region of Drummonds work? At the high heat flux end of Drummond’s data, it appears that there might be boiling

• Simulation results and discussion

•  I would assume that the single-layer MMC lacks the upper microchannel layer. It would be good to state this explicitly; something like: “The single-layer MMC lacks the upper microchannel layer, as depicted in Figure 2.”

• Figure 6

• Plotting in terms of the inlet velocity (particularly for the overall thermal resistance) might not be the best way to compare the single- vs double-layer MMC since the additional layer significantly increases the flow area (as shown in the pressure drop data). The increased flow area provides the opportunity to increase the inlet flow velocity in such a heat sink. You might consider plotting thermal resistance against pressure drop instead. This might also help visually separate the curves more.

• It might be good to include pressure drop results in Figures 8 and 9 in addition to Figure 6 

• Figure 9

• Your results show increased performance as the pin diameter increases. It would be good to show the diameter at which performance starts to decrease to get a sense on the limits of diameter increase (if such a limit exists)

• Height ratio section

• Was alpha = 1 for previous studies? This should be explicitly stated (if so)

• I don’t think that “supposed” is the right work; maybe “theorized” or maybe “observed” would be better; it seems that you have results to back up this line of reasoning; “supposed” doesn’t really seem strong / confident enough

• Figure 10

•  It’s really hard to see anything in the thermal resistance plot since the thermal resistance is a much stronger function of the inlet velocity than alpha; again, maybe plotting thermal resistance vs pressure drop would work out better; similar issue for the comprehensive performance parameter

Typos

• Author list: “and” should be between second-to-last and last author

• Abstract: In “Using the deionized water as working fluid”, “the” should be moved to before “working”

• Introduction:

• First paragraph

• “a” should be inserted between “and” and “chip’s”

• Third paragraph

• “fins array” should be “fin arrays”

• Should be “it was found that the cylindrical…”

• Should be “compared” not “compares” in last sentence

• Fifth paragraph

• “MMC heat sink has” should be “MMC heat sinks have”

• Sixth paragraph

• “Combining instead of “combing”

• Methodology

• Conservation of mass if the “Continuity” equation, not the “Continuum” equation

• No “the” needed between “and” and “deionized”

• Grid independence section

• Probably best to refer to the grid number in terms of elements (or something similar): “as the grid number exceeds 594758 elements”

• Need a different words than “consists”; meaning isn’t clear; maybe “trends with” or “follows”

• Simulation results and discussion

• “This is because when comparing with” instead of “This is because that comparing with”

• Height ratio section

• Just “alpha changes” not “The alpha change”

• “Fig. (10)” is not consistent with how other figures are referenced; the style of these references should be consistent throughout the paper

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Accept