Study of Cavitation on a Gerotor pump using GT-SUITE · Study of Cavitation on a Gerotor pump using GT-SUITE E. FROSINA, A. SENATORE , D. BUONO, F. P. BOVE DEPARTMENT OF INDUSTRIAL

Study of Cavitation on a Gerotor pump using GT-SUITE

E. FROSINA, A. SENATORE , D. BUONO, F. P. BOVE

DEPARTMENT OF INDUSTRIAL ENGINEERING, UNIVERSITY OF NAPLES FEDERICO II, VIA CLAUDIO 21, NAPLES 80125, ITALY

GT Conference 2017May 10 – 11

Prof. Ing. Adolfo SenatoreUniversity of Naples

Federico II

Dr. Dario BuonoPost Doc

University of Naples Federico II

Dr. Emma FrosinaPost Doc


Dr. Francesco Paolo BoveBorsista


Dr. Rosario IannuzziTesista


E. Frosina, Study of Cavitation on a Gerotor pump using GT-SUITEGT Conference 2017 - May 10 – 11

Dr. Francesco MeleBorsista


Dr. Fulvio Domenico Schiano di ColaTesista




E. Frosina, Study of Cavitation on a Gerotor pump with GT-SUITET Conference 2017 - May 10 – 11


Outlook

• Introduction

• Test Equipment and Measuring Method

• 1D Simulation Model

• Results

• Conclusions


Introduction

• Engine: 2 cylinder• Displacement: 875,4 cm3

• Max Power: 80 kW at 5500 rpm• Max Torque: 145 Nm at 1900 rpm

ENGINEDESCRIPTION


IntroductionPUMP

• Outer Gear: 10 Teeth• Inner Gear: 9 Teeth• Displacement: 5.2 cm3/rev


Introduction

NO CAV

CAV

NO CAV CAV


Test Equipment and Measuring Method

P1 = Mean Delivery Pressure Transducer

P2 = Mean Suction Pressure Transducer

P3 = Instantaneous Delivery Chamber Pressure

Transducer

P4 = Instantaneous Suction Chamber Pressure

Transducer

Q = Flow Meter

R1 = Suction Throttle Valve

R2 = Suction Calibrated Orifice

R3 = Delivery Calibrated Orifice

R4 = Delivery Throttle Valve





Suction

DeliveryCalibrated Orifices

E. Frosina, Study of Cavitation on a Gerotor pump with 1D Modelling ApproachT Conference 2017 - May 10 – 11



E. Frosina, Study of Cavitation on a Gerotor pump with 1D Modelling ApproachT Conference 2017 - May 10 – 11


Full Synthetic 5W40 Long Life Engine Oil

Viscosity (ASTM D445)80 cSt @ 40 °C / 13,7cSt @

100 °C

Viscosity Index 176

Sulphated Ash (ASTM D874) 1,3 wt %

Phosphorous 0,1

Flash Point (ASTM D92) 231 °C

Density (ASTM D4052) 0,85 g/ml @15,6 °C

Total Base Number (ASTM D2896) 11,8

MRV (ASTM D4684) 24,453 cP @ -35 °C

HTHS Viscosity (ASTM D4683) 3,9mPa · s @ 150 °C

Oil Properties



1D Simulation Model

Discretization of flow passages in the 1D model

The 1D pump flow model isdiscretized into many volumescomprised of pipes and flow splits(volumes), and pipe passages arefurther discretized into sub volumes.The 1D Navier-Stokes equations,namely conservation of mass,momentum and energy are solvedevery time step in every sub volume.Conservation of species is alsoconsidered to solve for speciestransport throughout the system. Inthe figure, the flow volumes used inthe model are shown by alternatingcolors. Both the inlet and outletports are divided into threesections for more accurate wavepropagation through the port.


161D Simulation Model

Since the pump has 10 outer teeth, there are 10 chamber volumes, and one cycle of the pump is represented asone revolution of the outer gear. The flow path from the oil pan to the chamber volumes is highlighted in blue,while the flow path from the chambers to the outlet is highlighted in red.

The leakage path between chambers is highlighted in green. The changing volume in each "Vol1", Vol2", etc…part pulls the oil from the pan into each chamber as its volume expands. Then when the volume in each chambercompresses, the oil is forced to the outlet side of the pump.

The internal leakage between each chamber is modeled with parts "gap1", "gap2", etc…



Three internal leakage paths are used in the model. The dominant path is highlighted green (leakage between teeth), the two minor paths are highlighted orange and pink.

1D Simulation Model

The 1D model was built directly from the CAD model of the pump using the GEM3D pre-processor of GT-SUITE.

1D Simulation Model


1D Simulation Model

The model has 133 total flow volumes, 110 of which are pipe sub-volumes

There are three distinct sections for both the inlet and outlet ports, to represent the flow area between the pumping chambers and these port sections.


Free/dissolved gas is included in the model, based on Henry’s Law

A time constant is used to control the rate at which air goes from dissolvedfree state andvice versa

The amount of gas that can be dissolved in a liquid at steady state is proportional to thepressure and dependent on the Bunsen coefficient, B

The Bunsen coefficient for oil/air mixtures is on the order of 0.08-0.09

The model assumes no free air at the oil pickup tube inlet, but 100% dissolved air in the oil

1D Simulation Model

atmliqssdgas P

PBVKbarV )273,1(,G

as d

isso

lved

Pressure

B

E. Frosina , Study of Cavitation on a Gerotor pump using GT-SUITEGT Conference 2017 - May 10 – 11

ResultsComparison between model results and experimental data with a Toil of 800C and a suction tube orifice diameter of 15mm


ResultsComparison with different suction tube orifice diameters, while holding outlet pressure at 3 bar and 800C

pout = 3 bar

MASSFLOW-RATE

NO CAV

CAV


ResultsComparison with different suction tube orifice diameters, while holding outlet pressure at 3 bar and 800C

pout = 3 bar

SUCTIONPRESSURE


0

1

2

3

4

5

6

0 60 120 180 240 300 360

PDELIVERY[bar]

Angle[deg]

3000rpm‐ TOIL=80°C

Results

NO CAV CAV

0

1

2

3

4

5

6

0 60 120 180 240 300 360

PDELIVERY[bar]

Angle[deg]

3000rpm‐ TOIL=80°C


Results

15mm

5mm

Pressure pulsation comparison at 3000 RPM and 800C

NO CAV

CAV


ResultsInfluence of oil type and suction tube diameter on pump mass flow

Toil = 200C Toil = 800C


Conclusions

• A numerical and experimental investigation on the cavitation in agerotor oil pump has been done.

• The pump has been forced to cavitate varying the suction pressure.

• An experimental investigation has been performed by theUniversity of Naples “Federico II” on a hydraulic test bench.


Conclusions

• The Pump performance in no-cavitating and cavitating conditionshas been measured; these data have been used to compare to the1D simulation model.

• The comparison between the model results and experimental datahas shown a good accuracy with a maximum gap of 7%.

• The model has demonstrated to correctly predict cavitation


Work in Progress• The model is able able to predict the power request of the pump

• Study of other Getoror pumps


Work in Progress• Gerotor pump cavitation Fault Diagnosis

• Study of other pumps like the vane pumps and the piston pumps


THANK YOU FOR YOUR ATTENTION

GT Conference 2017May 10 – 11

http://www.dii.unina.it/index.php/it/gruppi-di-ricerca

Emma [email protected]

Documents

Study of Cavitation on a Gerotor pump using GT-SUITE · Study of Cavitation on a Gerotor pump using GT-SUITE E. FROSINA, A. SENATORE , D. BUONO, F. P. BOVE DEPARTMENT OF INDUSTRIAL