Evaluation of the Thermofluidic Performance of Climatic Chambers: Numerical and Experimental Studies

Round 1

Reviewer 1 Report

In this article, a numerical model is proposed to evaluate the thermofluidic performance of a climatic chamber. The model is validated against experimental data. Although the proposed model seems interesting, I regret that I would like to reject the article for publication due to the following reasons: 

1. A similar article has already been published by the authors in the Journal of Thermal Science and Engineering Applications (APRIL 2020, Vol. 12 / 021014-1). There is no fundamental difference between the current article with the previously published version. The modeling approach is almost the same and the results are also similar. What is the necessity to publish the same research twice just by bringing little change in the analysis or manuscript?
2. Secondly, the current article lacks novelty. Such climatic chambers are already well designed and commercially available. What's new in the design of the current climatic chamber compared to the already available ones? Therefore, this reviewer feels that the current article will be of little interest to readers from the perspective of academic novelty. 
3. And lastly, for a climatic chamber, besides airflow and temperature, another important criterion is to control the relative humidity inside the chamber. Very little is mentioned in the current article about relative humidity and it is not included in the CFD model at all. 
4. Also, the description regarding experimental methods lacks detailed information. The mechanism of how relative humidity and temperature are controlled in the real device,  what are the achievable ranges of relative humidity and temperature in this device are also missing.  

Author Response

The attached file is a revised version of the former manuscript ID fluids-1377938, entitled “Evaluation of the thermofluidic performance of climatic chambers: Numerical and experimental studies”, with the introduced changes highlighted. All the comments and suggestions raised by the reviewers have been addressed.

The authors deeply appreciate the reviewers’ comments, ideas, and suggestions, and acting on them has helped us to enhance the quality of the manuscript and improve its clarity. We would like to acknowledge the time they have spent, and the dedication shown.

Reviewer #1

1. In this article, a numerical model is proposed to evaluate the thermofluidic performance of a climatic chamber. The model is validated against experimental data. Although the proposed model seems interesting, I regret that I would like to reject the article for publication due to the following reasons: 

A similar article has already been published by the authors in the Journal of Thermal Science and Engineering Applications (APRIL 2020, Vol. 12 / 021014-1). There is no fundamental difference between the current article with the previously published version. The modeling approach is almost the same and the results are also similar. What is the necessity to publish the same research twice just by bringing little change in the analysis or manuscript?

Authors’ response: Following these comments, the abstract and introduction have been reviewed to better define the paper's main scientific findings, namely, regarding the simulation of the moisture diffusion and the relative humidity measurements.

2. Secondly, the current article lacks novelty. Such climatic chambers are already well designed and commercially available. What's new in the design of the current climatic chamber compared to the already available ones? Therefore, this reviewer feels that the current article will be of little interest to readers from the perspective of academic novelty. 

Authors’ response: Following the reviewer’s comment, a short discussion about the novelty of the climatic chamber is now included.

3. And lastly, for a climatic chamber, besides airflow and temperature, another important criterion is to control the relative humidity inside the chamber. Very little is mentioned in the current article about relative humidity and it is not included in the CFD model at all. 

Authors’ response: Following these comments, moisture diffusion has been included in the CFD model. The experiments and numerical simulations conducted on the climatic chamber have been repeated.

4. Also, the description regarding experimental methods lacks detailed information. The mechanism of how relative humidity and temperature are controlled in the real device, what are the achievable ranges of relative humidity and temperature in this device are also missing.  

Authors’ response: The manuscript now includes detailed information about the experimental methods. The mechanism of how relative humidity and temperature are controlled, and the achievable ranges of relative humidity and temperature in the climatic chamber are now given in the text.

Reviewer 2 Report

Thank you very much for the opportunity to review the submitted text.The study is not innovative. The same way to use the Fluent module in ANSYS also. The research object seems interesting.

               This is insufficient for the state of the art. It is worth noting that the vast number of references come from the last century. During this time, researchers interested in using Fluent modul in flows, electrical engineering increased significantly.

               Hence, authors may not know how much is going on in their discipline.Instrumentation not shown. Where and how was measured. There is no measurement scheme and devices used.               It is therefore necessary to reliably refer to the prevailing trends. Against their background, demonstrating the uniqueness of the study. It is also necessary to describe the experiment in detail. It seems necessary to organize the numbering of the formulas and improve the quality of the text.

Author Response

The attached file is a revised version of the former manuscript ID fluids-1377938, entitled “Evaluation of the thermofluidic performance of climatic chambers: Numerical and experimental studies”, with the introduced changes highlighted. All the comments and suggestions raised by the reviewers have been addressed.

The authors deeply appreciate the reviewers’ comments, ideas, and suggestions, and acting on them has helped us to enhance the quality of the manuscript and improve its clarity. We would like to acknowledge the time they have spent, and the dedication shown.

 Reviewer #2

1. Thank you very much for the opportunity to review the submitted text. The study is not innovative. The same way to use the Fluent module in ANSYS also. The research object seems interesting.

               This is insufficient for the state of the art. It is worth noting that the vast number of references come from the last century. During this time, researchers interested in using Fluent modul in flows, electrical engineering increased significantly.

               Hence, authors may not know how much is going on in their discipline. Instrumentation not shown. Where and how was measured. There is no measurement scheme and devices used.              It is therefore necessary to reliably refer to the prevailing trends. Against their background, demonstrating the uniqueness of the study. It is also necessary to describe the experiment in detail. It seems necessary to organize the numbering of the formulas and improve the quality of the text.

Authors’ response to the reviewer: Following the reviewer's comment, the abstract and introduction have been revised to better define the paper's main scientific findings. The simulation of the moisture diffusion is now included and the measurement scheme and the experiment are described in detail, indicating the devices used. The numbering of the formulas has been reviewed. In line with these comments, the paper has been worked on to improve the overall quality.

Reviewer 3 Report

The authors present a study of the thermohydraulic behaviour and performance of a specific climatic chamber. Although, the authors claim the study to be both numerical and experimental, the exploitation of experimental data is scarce. The study is simple and is not targeted towards innovation for climatic chambers, but it can be of interest for the scientific community.

The numerical simulations performed and their analysis are convincing.

Here are some comments to improve the quality of the papers, especially regarding its clarity:

* Figure 2 could be improved by adding the different components. The applications of each boundary condition could then refer to the Figure, in order to facilitate the reading.

* It was not clear to me that solid parts are meshed in order to solve the energy equation, before seeing the temperature contours on Section 5. The authors must clarify this point before.

* The authors should comment on the Richardson number for their study.

* The first sentence of Section 3.1 must be rephrased.

* The authors could comment on the friction factor used in Eq (11).

* There is mention of a thermocouple but no temperature obtained from experiments are shown!

* How is the moisture taken into account in the governing fluid equations ? Is the contribution of the evaporator taken into account ?

* From Section 5, all the references to the Figures number are missing or wrong.

* The authors should comment on the asymmetry obtained experimentally for the velocity on Figure 9 (top velocity from right and left column), which is not observed numerically.

Author Response

The attached file is a revised version of the former manuscript ID fluids-1377938, entitled “Evaluation of the thermofluidic performance of climatic chambers: Numerical and experimental studies”, with the introduced changes highlighted. All the comments and suggestions raised by the reviewers have been addressed.

The authors deeply appreciate the reviewers’ comments, ideas, and suggestions, and acting on them has helped us to enhance the quality of the manuscript and improve its clarity. We would like to acknowledge the time they have spent, and the dedication shown.

 Reviewer #3

The authors present a study of the thermohydraulic behaviour and performance of a specific climatic chamber. Although, the authors claim the study to be both numerical and experimental, the exploitation of experimental data is scarce. The study is simple and is not targeted towards innovation for climatic chambers, but it can be of interest for the scientific community.

The numerical simulations performed and their analysis are convincing.

Here are some comments to improve the quality of the papers, especially regarding its clarity:

1. * Figure 2 could be improved by adding the different components. The applications of each boundary condition could then refer to the Figure, in order to facilitate the reading.

Authors’ response: Following the reviewer’s comment, Figure 2 has been improved. The different components are now given.

2. * It was not clear to me that solid parts are meshed in order to solve the energy equation, before seeing the temperature contours on Section 5. The authors must clarify this point before.

Authors’ response: Following the reviewer’s comment, the mesh is now better described.

3. * The authors should comment on the Richardson number for their study.

Authors’ response: Following the reviewer’s comment, the paper now states that the natural thermal convection is considered for heat transfer through the external walls of the climatic chamber. Thus, the Richardson number is not applicable in our problem.

4. * The first sentence of Section 3.1 must be rephrased.

Authors’ response: The first sentence of Section 3.1 has been rephrased.

5. * The authors could comment on the friction factor used in Eq (11).

Authors’ response: Following the reviewer’s comment, the friction factor used is now included (now Eq (12)).

6. * There is mention of a thermocouple but no temperature obtained from experiments are shown!

Authors’ response: Following the reviewer’s comment, temperature profiles inside the climatic chamber have been included in the paper.

7. * How is the moisture taken into account in the governing fluid equations ? Is the contribution of the evaporator taken into account ?

Authors’ response: The paper now describes how the moisture is taken into account in the governing fluid equations and how the evaporator is taken into account.

8. * From Section 5, all the references to the Figures number are missing or wrong.

Authors’ response: All references to the Figures’ numbers have been revised.

9. * The authors should comment on the asymmetry obtained experimentally for the velocity on Figure 9 (top velocity from right and left column), which is not observed numerically.

Authors’ response: Following the reviewer’s comment, the results obtained are now better discussed.

Round 2

Reviewer 1 Report

Thank you for revising this manuscript and including the modeling of relative humidity. Also thanks for improving the introduction and other sections. I think the manuscript quality has been improved quite a lot compared to the previous version. However, I would like to suggest one minor revision before acceptance. 

On page 13, to explain the deviation between CFD and experimental air velocity in Fig. 9 it was mentioned that, "the difference in precision
of positioning the measuring devices relative to the monitoring points in the numerical model can make some differences."

However, I think this difference may also come from the Turbulence model used in the study. On page 6, the authors mentioned that k-ω SST model was used here. Can you please also try the following models and see if the deviation can be minimized or not? 

• Renormalization-group (RNG) -  model
• Realizable -  model
• Standard -  model

In addition, how did you calculate the turbulence intensity in your simulation?

After you confirm the above queries, I can accept this paper for publication.

Best regards.  

Author Response

Reviewer #1

1. Thank you for revising this manuscript and including the modeling of relative humidity. Also, thanks for improving the introduction and other sections. I think the manuscript quality has been improved quite a lot compared to the previous version. However, I would like to suggest one minor revision before acceptance.

On page 13, to explain the deviation between CFD and experimental air velocity in Fig. 9 it was mentioned that, "the difference in precision of positioning the measuring devices relative to the monitoring points in the numerical model can make some differences." However, I think this difference may also come from the Turbulence model used in the study. On page 6, the authors mentioned that k-ω SST model was used here. Can you please also try the following models and see if the deviation can be minimized or not?

Renormalization-group (RNG) -  model

Realizable -  model

Standard -  model

Authors’ response: The numerical modelling has been repeated for the mentioned turbulence models, and the results were evaluated and compared with the experimental data (Figure 9, Figure 10, Table 3). A very small difference was observed between the results. However, the results from the RNG model were found to have better agreement with the experimental data.

2. In addition, how did you calculate the turbulence intensity in your simulation?

Authors’ response: There is no inlet flow boundary condition for the model. The fluid velocity and the associated turbulence intensity were modelled based on the fans’ model input data. The obtained turbulence intensity as the model’s output is 25%.

Reviewer 2 Report

Once again, thank you very much for the material sent.

I would like to mention that very similar studies have already been carried out. The authors' material does not differ from them.

I also have doubts whether the presented model can help in the process of designing climate chambers.

The very methodology of proceeding in the Ansys Fluent model is also not innovative.

Despite the significant improvement of the publication, I suggest that you reject it.

If I have any suggestions, I suggest developing a model on an innovative research object, using the Fluent module itself in an innovative way. So that the material can help the reader in carrying out other interesting tasks.

Best regards.

Author Response

 Reviewer #2

1. Once again, thank you very much for the material sent. I would like to mention that very similar studies have already been carried out. The authors' material does not differ from them.

Authors’ response to the reviewer: As mentioned in the introduction, a few studies concentrate on the experimental and numerical evaluation of the climatic chambers. However, as far as the authors know, the chamber's moisture diffusion has not been modelled before.

2. I also have doubts whether the presented model can help in the process of designing climate chambers. The very methodology of proceeding in the Ansys Fluent model is also not innovative. Despite the significant improvement of the publication, I suggest that you reject it.

If I have any suggestions, I suggest developing a model on an innovative research object, using the Fluent module itself in an innovative way. So that the material can help the reader in carrying out other interesting tasks.

Authors’ response to the reviewer: The authors regret the apparent failure to convey what the original contributions of the work are. An attempt has been made to rectify this in the modified and corrected version of the manuscript.

The CFD modelling has now been performed using different turbulence models to evaluate them based on the differences between numerical and experimental results. Also, the paper investigated the effect of thermal insulation on the thermal performance of the chamber. The current insulation (rock wool) was replaced by polyurethane insulation and the results are compared in Figure 19. In addition, two strategies to modify the airflow pattern within the chamber were studied. The outcomes have been added in section 5.4. The presented numerical study, which aims to analyse the performance of a climatic chamber at different temperature and relative humidity set points, will give a useful insight to the manufacturer to determine the possible weak points of the chamber. This information will be helpful in finding measures to optimise the performance of the chamber, as is now clearly shown in the paper.