Prediction and Optimization of Heat Transfer Performance of Premixed Methane Impinging Flame Jet Using the Kriging Model and Genetic Algorithm

Round 1

Reviewer 1 Report

The paper is well written and well organized. The topic is of interest for the scientific community. However, a number of shortcoming is present, namely:

- it is unclear to the reviewer if a grid dependence analysis has been performed

- it is unclear what the unique selling point of the paper is. Is it the reduced modeling effort? Is it the optimization procedure? The authors should explain better this point and how they advance the state of the art.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

The abstract necessitates additional elaboration on the genetic algorithm's (GA) significance, rationale for selection, and its practical implementation. A comprehensive overview of the methodologies employed is imperative for clarity and relevance.

The current introduction primarily focuses on the literature review, lacking discourse on motivations, contributions, and challenges faced in the field. Justification for methodological choices, notably GA, needs to be incorporated to elucidate their suitability and relevance.

Furthermore, recent articles such as "Evaluating the Performance of a Solar Distillation Technology in the Desalination of Brackish Waters" (Processes) should be integrated into the literature review to ensure comprehensive coverage.

A paragraph elucidating the paper's structure should be appended to the introduction, outlining subsequent sections' objectives and contents, thus enhancing the paper's coherence and navigational ease.

The resolution of Figure 1 requires enhancement to ensure optimal clarity and comprehension.

A meticulous definition of all notations, encompassing indices, parameters, and decision variables, is imperative to facilitate reader comprehension and interpretation of presented data.

There is no definition of the GA. Where is the chromosome definition? How did the authors do the mutation and crossover operators? Read some standard papers using the GA for optimization 

The conclusion should be extended to encompass a thorough discussion of the study's contributions, findings, limitations, and recommendations, including insights into potential future research avenues. This ensures a comprehensive understanding of the study's implications and significance.

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

This paper presents a study on the heat transfer performance of premixed methane impinging flame jets using computational fluid dynamics (CFD) coupled with a detailed chemical reaction mechanism for methane (GRI-Mech 3.0). The authors investigated the effects of equivalence ratio (ϕ), Reynolds number (Re) of the mixture, and normalized nozzle-to-plate distance (H/d) on the heat transfer characteristics. Kriging model and genetic algorithm were employed to analyze the simulation results, which significantly reduced the required number of CFD simulations and provided a reliable and accurate predictive model. Overall, this is a meaningful and well-conducted study. The main comments are as follows:

1. Relevance and Novelty: Premixed methane impinging flame jets are an important research topic in the field of combustion and heat transfer, with significant applications in various industrial sectors. By combining CFD simulations with surrogate model analysis, the authors systematically investigated the influence of several key parameters on the heat transfer performance, providing valuable guidance for engineering applications. The study is relevant to the field. The novelty lies in the integration of surrogate modeling and optimization algorithms to efficiently analyze a large number of CFD simulation results, thereby reducing computational costs.
2. Methodology: The authors employed the CFD method coupled with a detailed chemical reaction mechanism to simulate the premixed methane impinging flame jets. The accuracy of the simulations was validated against experimental results. Initial sampling points were designed using orthogonal arrays, and the Kriging model and genetic algorithm were utilized to analyze and optimize the heat transfer performance while significantly reducing the number of required CFD simulations. The overall methodology is reasonable and feasible.
3. Results and Discussion: The authors obtained response surfaces using the Kriging model and analyzed the influence of various parameters on the average Nusselt number. The mechanisms behind the impact of key parameters on heat transfer performance were further discussed using contour plots. The authors also identified the optimal parameter combination for achieving maximum heat transfer performance using a genetic algorithm. The results are adequately analyzed, and the discussion is reasonable.
4. Language and Other Aspects: The manuscript is well-written, with a clear structure and appropriate use of figures and tables. The references are comprehensive and relevant.

A few points to note:

1. Regarding the necessity and applicability of using the Kriging model, it is suggested that the authors provide additional discussion.
2. It would be helpful if the authors could further clarify the mesh independence verification in the CFD simulations.
3. In the future work outlook section, the authors are encouraged to discuss an optimization framework that considers both heat transfer enhancement and pollutant emissions in practical engineering design optimization.

In conclusion, this study makes important academic and engineering contributions to the understanding of heat transfer mechanisms and optimization in premixed methane impinging flame jets. The manuscript is likely to be suitable for publication after minor revisions.

The manuscript is generally well-written, but there are a few areas where the language and grammar could be improved. Here are a few examples of grammatical errors or areas for improvement in the manuscript:

1. In the abstract, the sentence "This method significantly reduces the simulated times of CFD and obtains a reliable and accurate prediction model." could be rephrased as "This method significantly reduces the number of CFD simulations required and provides a reliable and accurate prediction model."
2. In the introduction, the sentence "IFJ can provide local heating, have short start-up and cool-down times, and obtain greater heat flux than high-cost radiant heating technology." could be improved by adding a parallel structure: "IFJ can provide local heating, has short start-up and cool-down times, and obtains greater heat flux than high-cost radiant heating technology."
3. In the numerical simulation section, the sentence "Five layers of stainless steel mesh are installed in the burner to reduce the mixture's flow fluctuations, ensure uniform flow, and prevent flame flashback." could be rephrased as "Five layers of stainless steel mesh are installed in the burner to reduce flow fluctuations of the mixture, ensure uniform flow, and prevent flame flashback."
4. In the results and discussion section, the sentence "It is found that the influence of the equivalence ratio is more significant as the Reynolds number rises." could be improved by clarifying the meaning: "The influence of the equivalence ratio on heat transfer performance becomes more significant as the Reynolds number increases."
5. In the conclusion, the sentence "This study provides an efficient method framework for the heat transfer performance of PMIFJ in practical applications." could be rephrased as "This study presents an efficient framework for analyzing and optimizing the heat transfer performance of PMIFJ in practical applications."

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The authors have revised the paper.