Effects of Orifice Sizes for Uncontrolled Filling Processes in Water Pipelines

Round 1

Reviewer 1 Report

Effects of orifice sizes for uncontrolled filling processes in water pipelines

ID: water-1618212

 

Comments and Suggestions for Authors

 

A brief summary

The article concerns the determination of the hydraulic characteristics in the conditions of water filling a pipeline with a pillow - an air pocket and an air valve. An air valve is installed at the highest point of the pipeline. There are also drain valves in piping systems, which the Authors of the article did not take into account. Laboratory tests of the conduit indicate that it is filling the left supply part of the pipeline. The right falling part is filled with water. Air collects in the upper part of the ascending section and in the pipe bend. There is an air valve at the highest point of the pipe knee. During filling, there is no water flow to the right descending section. The pipe knee is filled when the water level in the pipeline reaches the bottom edge of the pipe knee. The described hydraulic diagram is water filling the air cushion pipe. The air valve is open during filling.

 

Broad comments

There are also drain valves in piping systems, which the Authors of the article did not take into account. During pipeline repairs, water is drained from the section between the safety valves. In the analyzed scheme, there is no phase of filling the right descending part of the pipeline with water. The conducted analyzes can be the basis for developing the characteristics of air valves.

 

Specific comments

 

(R.12) 1. Introduction.

 

 

(R.71)  2. Experimental model

Comment.

Please describe the methodology of the experiment. Report the condition of the air valve. The modelled air pocket occurs in the section of the air valve. In the initial setting, the air valve is open. The left and right safety valves are closed. There is atmospheric pressure in the pocket. Filling the left pipeline with water begins with the sudden opening of the left valve. The pipeline is filled with water from the tank. The pressure in the tank is the sum of the water column pressure Hi (m.wc), atmospheric pressure Patm (m.wc) and pressure Pi (m.wc). The Reviewer does not see in the hydraulic diagram the Hi (m.wc) pressure of the water column in the tank above the water level in the left pipeline, graph in figures 1. Please explain it and correct it.

 

Figure 1. Conceptual scheme of the experimental facility.

It must be corrected.

Please mark the pressure in the hydro - pneumatic tank as Pi (m.wc). The height of the water column, Hi (m.wc), above the water level in the left pipeline at zero time should be determined.

 

 

(R.82-83). It must be corrected.

Three (3) experimental tests were conducted in this research, considering different initial hydro-pneumatic pressure heads Pi (m.wc), water head Hi (m.wc) and air pocket sizes Xo (m).

 

Table 1. Test characteristics

It must be corrected.

Should be Pi (m.wc), pressure dimension meter water column (m.wc).

Please add the row Hi (m.wc).

 

(R.85)  3. Numerical CFD Model

 

(R.86-87). It must be deleted.

Please remove the text from lines 86-87. With the proposed division of the text, there is no text after the header of a higher order.

 

(R.88).                                    3.1. Governing equations

(R.106).                       3.2. Turbulence model

(R.123).                       3.3. Assumptions, boundary conditions and mesh properties

 

(R.162). 4. Results and discussions

 

Figure 4. Comparison between measured and computed air pocket pressure patterns

It must be corrected

Vertical axis of the charts (a) Test 1; (b) Test 2; (c) Test3 should be (m.cw).

 

(R.145-155)     4. Discussion

 

Figure 5. Conceptualization of the uncontrolled filling process of the Experimental Test No. 1

Please describe briefly which filling steps have been defined (Stage 1,… ..Stage 2 …… Stage 3 ……, Stage 4 …….). Selected stage points are shown in Figure 5. The vertical axis of the graph should have the dimension (m.cw).

 

Figure 6. Air-water interface during Stage No. 1 to No. 4 ocurrences for Experimental Test No. 1

It must be corrected.

For each diagram, please provide the exact time for which the graphical presentation of the flow was made. As shown in figure 5.

 

Figure 7. Comparison of air pocket pressure patterns using the air valve S050 (diameter of 3.175 mm) and the Discharge Orifice of 7.0 mm

It must be corrected

The vertical axis of the graph should have the dimension (m.cw).

 

(R.208) 5. Conclusions

Author Response

Dear Reviewer:

Please, see enclosed file.

Author Response File: Author Response.pdf

Reviewer 2 Report

This paper deals with the impact of air valves on rapid filling processes in pipelines, comparing an experiment with a 2D numerical model. Overall I think the work is acceptable, with the introduction, experiment and model well explained. However I believe the authors could expand on their findings in the Results and discussions section. The authors focus mainly on the results of Test 1, with little or no discussion of tests 2 and 3, with no explanation of the differences seen in these tests and the consequences drawn. Also the authors do not explain the disparity between the measurements and CFD Model for tests 2 and 3 seen in figure 4b and 4c? These points should be expanded on in any re-submission.

Apart from these the following minor typos were spotted.

line 5, Abstract: change "studied for" to "studied by"

line 19: remove the word "demonstrate", not needed when word "exhibit" is used

line 20: remove word "an" at end of line

line 22: change "Air valve" to "Air valves"

line 23: change "capable" to "able"

line 25-26: sentence badly phrases, I believe it would be better stated something like this "Air valves can be classified by different types with air-release valves (ARVs) being the most common type to expel..."

line 49: add word "a" before "2D CFD"

line 54: change "by the" to just "by"

line 69: change "purpose" to "purposes"

line 73: change "composed by" to "composed of"

line 95: remove word "the" before word "Newton's"

line 104: add word "to" after word "correspond"

line 119: should "energy kinetic" not be "kinetic energy"

line 215: change word "recommendable" to "recommended"

 

Author Response

Dear Reviewer:

 

Please, see enclosed file.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

I am happy with the authors revision and now accept the article for publication.