analysis of negative pressure to increase the capacity of a pulsator

Analysis of Negative Pressure to Increase the Capacity of a Pulsator

Analysis of Negative Pressure to Increase the Capacity of a Pulsator

Final Presentation

By: Michael ManganC00173405Supervisors:Andrew KeppelCathal NolanJoe Dillane Patrick Buckley

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ContentsIntroductionObjectiveMaterials & MethodsResultsConclusionsRecommendations

Introduction Pearson PulsatorRegulates flow

Pearson PulsatoroPearson international from Athy brought this project to the college.oThey want to improve on their Pulsator. Regulates flowoThe Pulsator is a vital part of the milking process as it regulates the flow that is coming from the cows teat. This is important as it helps the animals health. This diagram shows the different components that make up the milking process.

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ObjectiveAnalyse vacuum through Pearson PulsatorChanging geometryFurther improvements

Analyse vacuum through Pearson PulsatoroThe main objective is to analyse the flow of air through a Pearson Pulsator.oAnd to increase the capacity by increasing the volume flowrate. Changing geometryoThis will be achieved by changing the geometry.Further improvementsoFrom this, further improvements will be made to the geometry.4

Materials & MethodsPulsator

oIn this picture we can see the areas of interest belonging to the Pulsator that will be examined, including the port, chamber, outlet, & plunger.5

Materials & MethodsPulsatorSpaceClaim

oThe geometry was then brought into an ANSYS application called SpaceClaim where the volume was extracted and the geometry cleaned up.oThe cut-off line demonstrates where the geometry was separated for a shorter solve time in Fluent.

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Materials & MethodsPulsatorSpaceClaim Named Selections

oHere we can see a 2d model containing named selections.oThis model was created from the volume extract in 6 different parts and each part was then assembled together.oDifferent areas were assigned names relevant to their purpose.oFor example, areas with zone as a suffix show that there may be fluid motion in this zone.oIts important in Fluent to label correctly as it tells the software how to behave relative to this.

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Materials & MethodsPulsatorSpaceClaim Named SelectionsMesh

oA 0.5mm mesh was applied to the model.8

Materials & MethodsFluent

SetupGeneralModelsDescriptionType Pressure BasedViscous k epsilon (2 eqn)2D Space Planar K epsilon model - RealizableNear wall treatment Enhanced wall functionEnergy On

oThis table shows the setup that was employed for analysis in Fluent.oA pressure based transient solve was used and a k-epsilon realizable enhanced wall function was chosen.oThe enhanced wall function was chosen as it acts in much the same way as an inflation layer.

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Materials & MethodsFluentBoundary Conditions

Boundary ConditionsTypePressure [Pa]Hydraulic [m]Inlet Pressure Inlet00.0105Outflow Pressure Outlet500000.014

oThe pressure at the inlet was set to 0Pa as this can be treated as gauge pressure with a hydraulic diameter of 10.5mm.oThe outflow pressure was set at 50000Pa as this was the value recorded by Pearsons with a hydraulic diameter of 14mm.

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Materials & MethodsFluentBoundary ConditionsProject Setup

oHere we can see the different types of mesh applied as well as the named selections.oAlso the parts that were assembled in the project setup in Fluent.oThere was a face mesh applied to the port and the left-lower-zone and set to triangles as there is motion in these zones.

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oAn edge sizing with 20 divisions was set at the port-entry as this is an area that will be explored. 12


oA body sizing of 0.5mm was then applied to the rest of the geometry and set to quadrilateral.13

Materials & MethodsFluentBoundary ConditionsProject SetupDynamic Mesh

oA layering method which is a type of dynamic mesh was applied.oThis allows the mesh to deform and reform in a linear movement.oA UDF was also created based on the size of the chamber and it moved at 100Hz based on information from Pearsons.

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Materials & MethodsPhysical models

oTesting would be completed on the original and modified models.oIn this picture, the area that was altered can be seen.oThe port-entry diameter was modified and increased.

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Materials & MethodsPhysical modelsAlterations

oThe length of the port is to be extended incrementally by 2 mm each time to 10 mm.oThe radius is to be altered by values of 0.5 mm or 1mm, by increasing or decreasing the radius.

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Materials & MethodsPhysical modelsAlterations

oThe port-entry diameter will be increased by 0.1mm each time.oThe reason for the different values being changed is that the company is not looking for a complete redesign.oThis means that the port-entry and the radius were limited by the amounts that they could be altered as it could affect the overall geometry and that would have a cost implication.

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Materials & MethodsPhysical modelsAlterations New design

oHowever, with this in mind, a modified geometry was created for comparison.oBased on the theory in the lit review, the geometry was altered accordingly.oThe radius was altered significantly for testing as the picture illustrates.

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ResultsPhysical Models

oTesting was undertaken at Pearsons in Athy. For the original model, values of 300l/min were recorded but for the modified model it failed. oThere was an issue with the printed model and ridges prevented the seal from sitting properly, so air escaped from the Pulsator.

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ResultsPhysical ModelsPort-EntryTurbulence Kundu et al

ResultsPhysical ModelsPort-EntryY.Cengel et.al

Port-Entry [mm]Calculated Q Total [l/min]Converted to Known ValueExpressed as a Percentage6.9252023.334300100%7806831.46960320%7.1202579.62624180%7.2312915.324372124%7.3535839.114638213%7.455018.03326522%

oFirstly, when the diameter was 7mm, a value of 320% increase was recorded which seems to be disproportionately high.oAfter this point the results appeared to behave in a way that is supported by literature from Cengel et.al that as the area increases the volume flowrate also increases.oAt 7.3mm a more realistic result of 213% is displayed.oThe graph provides a little more detail of this.

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ResultsPhysical ModelsPort-Entry

ResultsPort lengthOoi et.al

Change in Length [mm]Q Inlet [l/min]%0-60769.866100%2-61231.914101%4-61769.628102%6-62595.576103%8-63009.318104%10-63665.556105%

oAs the port length increased by 2mm each time it displayed a linear relationship and rose by 1% for each 2mm increment.oIt was tested to 10mm where it reached its max of 105%.oThis corresponds with studies done by Ooi et.al that by increasing the pipe length, the shear stress decreases and there is less turbulence.

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ResultsPort lengthPort radiusOwer et.al

Radius Change [mm]Inlet Q [l/min] % 0.92356185.96104%0.952456223.78108%0.982268252.96100%12296236.6101%1.52194780.6897%22204298.9697%2.52157235.0295%

oThe most significant result is when the radius was reduced to 0.95mm, this was the expected result as Ower et.al investigated the effects of bends and determined that the resistance coefficient reduces but only to a point where the effects then start to retard.24

ResultsModified

oIn this model it can be seen that the effect of turbulence is much lower than before and theres not as much in the port.oA 116% increase was achieved when tested.oThis rose to 465% when the port was extended to 10mm which does seem disproportionately high.

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ResultsModified

ParameterNew Q [m^3/s]% IncreasePort length Increase [mm]New Q [m^3/s]% IncreaseInlet-1.1411613%10-1.255525%Total-34.7228116%10-91.005465%

oIn this model it can be seen that the effect of turbulence is much lower than before and theres not as much in the port.oA 116% increase was achieved when tested.oThis rose to 465% when the port was extended to 10mm which does seem disproportionately high.

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Conclusions Success?Objectives met?

Positive resultsAnalyse vacuum through Pearson PulsatorFurther improvementsChanging geometry

oWas it a success?Objectives met?oOne way to measure if it is successful is to check whether the objectives were met.oAnalyse vacuum through Pearson Pulsator. This was done through recording values for the volume flowrate.oChanging geometry. The radius, port-entry, and port length were all altered.oFurther improvements. Improvements were either recorded or suggested based on this.Positive resultsoThe results agreed with the literature review somewhat which suggests positive results.

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Conclusions IssuesLarge Values

oThere were however some issues.Large valuesoThe values recorded were very large but compared in percentage, they behaved as expected.oA possible reason for these results is the excel file created.oAs you can see here, there is only 2Hz when it should be displaying 100Hz.

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Conclusions IssuesLarge Values

oThere were however some issues.Large valuesoThe values recorded were very large but compared in percentage, they behaved as expected.oA possible reason for these results is the excel file created.oAs you can see here, there is only 2Hz when it should be displaying 100Hz.

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Conclusions IssuesLarge ValuesResults

TypePoint of Max ValuePercentage ChangeRadius [mm]0.95108%Port Length [mm]10105%Port-entry Diameter [mm]7.3213%Port-entry Diameter [mm]7.0320%

oThis table shows the maximum results that were recorded for each change to the geometry.oHowever, it is felt that the port-entry diameter requires further analysis of a more in depth nature.

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Recommendations Future Work

oThere are a few recommendations for further analysis.oIt is felt that to get more accurate results, the whole model needs to be looked at in a 3-d solve.oAlso that parameters such as temperature may be taken into account.

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oFurther analysis could be undertaken on the modified 2-d model that achieved such large results.oA further in depth investigation could be carried out.

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oFurther analysis could be undertaken on the modified 2-d model that achieved such large results.oA further in depth investigation could be carried out.

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o3-d analysis to be run on the current model and compared to literature review.oA mathematical model could be created for comparison.

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Q & A

Thank you for Listening

Any Questions?

References

Y. Cengel; M. Boles. (2007). Thermodynamics, An Engineering Approach, 5th Edition. Ooi, K. L. J. P. M. M. S. C. and A. (2004). The Entrance Length for Fully Developed Turbulent Channel Flow. Kundu, P. K., Cohen, I. M., & Dowling, D. R. (2016). Fluid Mechanics. Fluid Mechanics. Elsevier.Mr. Andrew KeppelMr. Joe Dillane

analysis of negative pressure to increase the capacity of a pulsator

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