Research on Flow Characteristics of Straight Line Conjugate Internal Meshing Gear Pump
Round 1
Reviewer 1 Report
- The research on which the content of article is based must have been carried out with a high degree of accuracy and must have been very time consuming.
-Also in view of this fact it is my opinion that the value for readers and/or applicators could be increased considerable by more emphazing on the possible claims of this research, such as:
* The improvement of the detemination of the theoreitcal sweptvolume (geometrical Volume).
*The improvement of the determination of the volumetric efficiency and the
hydo-mechanical efficiency, keeping and mind that internal gear pumps have basically a high till very high volumetric efficiency.
Author Response
Dear reviewer:
I am very grateful to your comments for the manuscript. We will seriously consider your views in future research. The purpose of our work is to provide reliable data for an accurate calculation of the theoretical flow rate and the geometric flow pulsation rate, provide theoretical foundation to increase the geometric displacement, decrease the flow pulsation to reduce the pressure shock noise, and improve the overall performance of gear pumps comprehensively.
Reviewer 2 Report
Please refer to the following issues regarding internal gear pump design.
The current trend in pump drives is to strive to minimize the weight of devices by introducing improved and high-strength materials, composites and thinning elements construction.
For internal gear pumps, the qv/V coefficient was introduced allowing to compare pumps in terms of theoretical flow rate in relation to their weight.
When designing internal gear pumps one should strive for the use of gear rings with the smallest possible difference in the number of teeth, which reduces the value of the geometric flow pulsation rate and improves the ratio of performance to weight of the pump.
Tests are carried out on internal gear pumps with tooth modification to reduce its weight in relation to flow rate and to decrease the value of the geometric flow pulsation rate.
Technical Notes:
– in diagram Fig.16 spill valve symbol 14 should be drawn inversely!
– in the designations of equations (14) - (16) are two Greek letters?
Author Response
Dear reviewer:
I am very grateful to your comments for the manuscript. According with your advice, we have changed the arrow direction of the electromagnetic spill valve (14) in design schematic figure 19. Another question from you have been answered below.
In the designations of equations (14) - (16) are two Greek letters?
Reply:
Yes, there are two Greek letters( and ), the single Greek letter means theoretical displacement. The combination of and (i.e.,) means oil-discharge volume of each pair of gears.
Reviewer 3 Report
Authors carried out a theoretical, computational and experimental analysis of straight-line conjugate internal meshing gear pump. The flow characteristics under no-load conditions from the theory, numerical simulations and experiments should be listed in one table.
The authors mentioned a previous analysis and article many times in the manuscript. What is that? Kindly cite the previous article [14].
The resolution of figures 5, 6, 17 and 19 are poor. Kindly improve it.
Combine Figures 7 and 8.
Merge Figures 9 and 10.
In Figure 12 caption, replace ‘4-oil-distribution area; 5-oil-distribution area.’ with ‘4-oil-distribution area on the absorption side; 5-oil-distribution area on the discharge side.’
What is the turbulence model used in the simulations
On page 16, what is the meaning of grid number and node number?. In general, the number of nodes or grid points and the number of elements in the various computational mesh are listed for a grid convergence study.
Correct spelling, grammatical errors in the manuscript. For example, correct ‘the gear and the gear surface on page 15’, gird interface technology on page 15, and ‘the change amplitude of the average flow’ on page 19,
Rewrite the statement on page 16, ‘After the calculation converging, the pressure cloud diagram on the symmetrical cross section and the rotor section, the oil distribution area when absolute pressure is lower than 3000 Pa, the velocity vector diagram, the instantaneous and average flow rates curves in the eighth cycle are extracted. The specific results are as follows.’
Author Response
Dear reviewer:
I am very grateful to your comments for the manuscript. According with your advice, we have added Table 6 to the 25 pages of the manuscript, which lists the flow characteristics under no-load conditions obtained by theoretical analysis, numerical simulations and experimental researches, and compared and analyzed them. We have improved appropriately the resolution of figures 5, 6, 17 and 19. We have Merged Figures 7 and 8, and Figures 9 and 10. We have replaced ‘4-oil-distribution area; 5-oil-distribution area.’ with ‘4-oil-distribution area on the absorption side; 5-oil-distribution area on the discharge side’ in Figure 12 caption. We have corrected spelling, grammatical errors in the manuscript. We have revised the statement on page 16.
‘After the calculation converging, the pressure cloud diagram on the symmetrical cross section and the rotor section, the oil distribution area when absolute pressure is lower than 3000 Pa, the velocity vector diagram, the instantaneous and average flow rates curves in the eighth cycle are extracted. The specific results are as follows’
To
‘After the numerical simulation converged, we obtain the calculation results in the eighth cycle, such as the pressure cloud diagram on the symmetrical cross section and the rotor section, the oil distribution area when absolute pressure is lower than 3000 Pa, the velocity vector diagram, the instantaneous and average flow rates curves, as shown below.’
Some of your questions have been answered below.
- The authors mentioned a previous analysis and article many times in the manuscript. What is that? Kindly cite the previous article [14].
Reply:
Thank you for pointing this out. There are two “previous analysis” and “previous article” in the manuscript, respectively. They exist in the following four sentences.
“From the previous analysis, we can know that when the meshing point coincides with the node…”
“According to the previous analysis, under the working conditions applied in this study…”
“According to the relevant settings of previous article, the simulation calculation of the flow channel model is performed…”
“From the previous article, the geometric flow pulsation rate is 1.76%, accounting for 19.9% of the total flow pulsation rate…”
Here, what we want to express is the aforementioned analysis and the aforementioned results in my research. We have not quoted the conclusions of others. The word previous was used incorrectly, and we have corrected it in the manuscript.
- What is the turbulence model used in the simulations
Reply:
The turbulence model in the manuscript selected the RNG model that can better handle high strain rates and greater degree of streamline bending.
- On page 16, what is the meaning of grid number and node number?. In general, the number of nodes or grid points and the number of elements in the various computational mesh are listed for a grid convergence study.
Reply:
Before the simulation calculation, the division of the computational grid is performed first. For the computational model in the manuscript, the hexahedral structured grid cells are used for meshing. In the entire computing domain, grids are connected by nodes, and different grid number correspond to different node number. Various physical units are transmitted through nodes. After the grid is divided, the grid independence verification is performed immediately, that is, when the grid is encrypted to a certain degree, the calculation result does not change with the number of grids. Finally, a grid model with good convergence and small grid number is selected.
