Study on the Comparison of the Hydraulic Performance and Pressure Pulsation Characteristics of a Shaft Front-Positioned and a Shaft Rear-Positioned Tubular Pump Devices
Round 1
Reviewer 1 Report
The article studies the effect of the shaft position on the performance of a tubular pump device, the optimized shaft front-positioned and shaft rear-positioned pump device. The article has publishable material and my comments are as follows:
- Provide the origin of all tables.
- Why the authors have selected the proposed technique? Alternatively, can you compare your results with others for validation?.
- Minor glitches must be removed and insert full stop/ comma at the required place after each equation.
- Similarity index needs to be reduced.
- Describe the details about the computational software used to plot the graphs in the discussion section.
- For fortifying the introduction section with the new publications, old references should be replaced with new ones such as:
Thermodynamic entropy of a magnetized Ree-Eyring particle-fluid motion with irreversibility process: A mathematical paradigm
Accordingly, I advise that the manuscript is put under revision until the inquires addressed are responded to.
Author Response
Point 1: Provide the origin of all tables.
Response 1: Thanks for the reviewer's comment. Table 1 shows the physical parameters of TJ04-ZL-06 pump. Table 2 shows the boundary conditions of numerical computation domain and the total time and time step of the unsteady calculation. Table 3 shows the name and accuracy of the experimental instruments.
Point 2: Why the authors have selected the proposed technique? Alternatively, can you compare your results with others for validation?
Response 2: Thanks for the reviewer's comment. In this study, the numerical simulation employs the renormalization group (RNG) k-ε turbulence model. When water flows through the blade passage of the axial-flow pump impeller, a higher strain rate and large bending streamline are produced. The RNG k-ε model uses a statistical technique called renormalization grouping to correct the turbulence viscosity by considering the conditions of rotation and swirl. The RNG k-ε model performs better than other turbulence models in the internal flow field calculation process of axial-flow pumps. The results of reference [26-30] also can show that RNG k-ε model can be applied to the calculation of flow field of pump.
Point 3: Minor glitches must be removed and insert full stop/ comma at the required place after each equation.
Response 3: We are grateful to the reviewer for pointing out these glitches. We are sorry that this problem was caused by our negligence and this mistake have been corrected in revised manuscript. Please see in the Equations.
Point 4: Similarity index needs to be reduced.
Response 4: Thanks to reviewer for requirement on similarity index. We have modified it in the revised manuscript.
Point 5: Describe the details about the computational software used to plot the graphs in the discussion section.
Response 5: Thanks for the reviewer's comments to help us re-examine the parts ignored in the software introduction. The information about the software used to plot the graphs has been supplemented in the revised manuscript. Tecplot Software is used to draw the flow field diagram in this paper, and Origin Software is used to draw the curve diagram. Please see in the first paragraph in section 4.1 and the first paragraph in section 4.2.
Point 6: For fortifying the introduction section with the new publications, old references should be replaced with new ones such as: Thermodynamic entropy of a magnetized Ree-Eyring particle-fluid motion with irreversibility process: A mathematical paradigm
Response 6: Thanks for the reference provided by the reviewer. The reference has been referred in the revised manuscript. Please see in the reference [20].
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The article deals with very interesting analyzes of a tubular pumping device placed in front of the shaft and behind the shaft. The study investigated theoretically and experimentally the impact of the shaft position on pressure pulsations, hydraulic losses and the efficiency of a tubular pumping device. These types of analyzes provide practical guidance on the design and optimization of a tubular pumping device. The work is very interesting and suitable for publication in the Journal of Marine Science and Engineering, but needs some improvements:
- In my opinion, the introduction should be extended to include bibliographic analysis from other world (except Asian) research centers.
- Figure 1 shows 3D models of two analyzed pumps. These are ready-made design solutions that differ significantly in the dimensions of the pump inlet and outlet. In my opinion, the analysis would be more complete if numerical calculations were performed for different geometries of the pump inlet and outlet channels. Maybe the issues of efficiency and pressure pulsation would be different? These would also be design guidelines.
- The obtained results of numerical calculations show very good agreement (Fig. 6 and Fig. 7). I wonder how to physically explain the decrease in H (m) for Q / Qd ~ 0.5 and thus how it was taken into account in the numerical model.
- The summary lacks a clear emphasis on practical tips resulting from the numerical analyzes carried out.
- As I wrote before, I have no references in the bibliography to more global bibliographic items in this field of knowledge.
Author Response
Point 1: In my opinion, the introduction should be extended to include bibliographic analysis from other world (except Asian) research centers.
Response 1: Thanks for the reviewer's comment on the introduction. Relevant researches from other world (except Asian) research centers have been supplemented in the revised manuscript, please see in the introduction.
Point 2: Figure 1 shows 3D models of two analyzed pumps. These are ready-made design solutions that differ significantly in the dimensions of the pump inlet and outlet. In my opinion, the analysis would be more complete if numerical calculations were performed for different geometries of the pump inlet and outlet channels. Maybe the issues of efficiency and pressure pulsation would be different? These would also be design guidelines.
Response 2: Thanks for the reviewer's comment. According to Chinese standard, during the design of large and medium-sized pump stations, an axial-flow pump device consisting of an axial-flow pump and an inlet and outlet passage must be used. In this paper, both the shaft front-positioned and the shaft rear-positioned tubular pump device adopt TJ04-ZL-06 pump model. The inlet and outlet size of pumps are the same, the size of inlet and outlet passage were specifically optimized. We will write another paper on optimizing the size and shape of the flow channel. Thanks again for the comment of reviewer which provide guidance for our future work.
Point 3: The obtained results of numerical calculations show very good agreement (Fig. 6 and Fig. 7). I wonder how to physically explain the decrease in H (m) for Q/Qd ~ 0.5 and thus how it was taken into account in the numerical model.
Response 3: Thanks for the reviewer’s question about Q-H curve. This phenomenon proposed by reviewer is determined by the nature of the axial-flow pump itself. The impact angle of water flow and blade increases with the decreasing of flow rate. When the impact angle increases to a certain extent, the lift coefficient decreases and the head decreases, forming a saddle zone on the Q-H curve. Therefore, the reduction of H has nothing to do with the numerical model but only with the properties of the axial-flow pump itself.
Point 4: The summary lacks a clear emphasis on practical tips resulting from the numerical analyzes carried out.
Response 4: Thanks for the reviewer's comment. We have made supplements in the revised manuscript. Please see in the Conclusions.
Point 5: As I wrote before, I have no references in the bibliography to more global bibliographic items in this field of knowledge.
Response 5: Thanks for the reviewer's comment on the references. References from other world research centers have been supplemented in the revised manuscript, please see in the references [17-18], references [20-24], reference [26] and reference [31].
Author Response File: Author Response.pdf
