Chen, Zixiang

Eberle, Kelly

Grose, Jordan

Ijeomah, Cajetan

English

Texas A&amp;M Repository

Benefits of Installing Restrictive Orifice Plates on the Suction of Reciprocating Pumps:1D Pulsation and CFD StudiesPresenter: Kelly Eberle, PEng, Principal Consultant, Wood Presenter/author biosZixiang Chen, Wood Group (formerly BETA Machinery Analysis), PhD, EIT, Engineer – Zixiang has recently completed his doctoral work in the field of fluid dynamics. His academic research interest is on the sensor-based estimation of large-scale coherent structures in turbulent flows using optical flow diagnostics and numerical simulations. Prior to joining Wood Group in 2014, he worked on combustion modelling for the GT24/26 and compressor aerodynamics for the PT6.Cajetan Ijeomah, Wood Group (formerly BETA Machinery Analysis), MSc, PEng, Senior EngineerCajetan is a professional engineer with over 14 years of industry experience, the majority of which is in dynamic engineering and vibration design. His responsibilities include acoustical (pulsation), mechanical and thermal analysis of reciprocating compressor and pump systems, evaluation of piping systems and related dynamic studies. Cajetan manages complex design projects involvingmultiple vibration disciplines and is proficient in the use of various engineering analysis software tools.Jordan Grose, Wood Group (formerly BETA Machinery Analysis), PEng, MBA, Service Leader – AmericasJordan is a mechanical engineer with extensive domestic and international design, field, and monitoring experience with compressors, pumps, pipelines, and other production machinery. He has specialized skills in vibration, liquid transient analysis, performance, and troubleshooting in onshore and offshore production facilities. Jordan currently leads Wood Group’s vibration integrity group in addressing plant-wide vibration risks in piping and machinery systems. He has been with Wood Group (formerly BETA Machinery Analysis) for over 14 years, during which time he has authored and co-authored several papers. Jordan was formerly responsible for BETA’s Malaysia office in Kuala Lumpur. Kelly Eberle, Wood Group (formerly BETA Machinery Analysis), BSc, PEng, Principal Consultant Kelly is a principal consultant and has been with Wood Group (formerly BETA Machinery Analysis) since 1988. He has accumulated a wide range of design and field experience, particularly in the area of pressure pulsation analysis and mechanical analysis of reciprocating compressor and pump installations. The scope of his experience includes pulsation simulations, thermal flexibilitystudies, dynamic finite element analysis, structural analysis and foundation analysis.AbstractIt is well understood that static pressure at the inlet of reciprocating pumps, quantified typically by Net Positive Suction Head Available (NPSHA), must be sufficient to avoid cavitation in the pump suction manifold and chamber. In an effort to conserve NPSHA, pump designers generally rely on rules of thumb that resist the addition of pressure drop elements such as restrictive orifice plates, choke tubes and line-size reductions to the inlet piping of all pumps, including reciprocating pumps. Another design consideration of reciprocating pumps is the generation of pressure pulsations due to pump piston and valve motion. Uncontrolled pulsations can result in cavitation and vibration-related fatigue failures. In many cases, pressure drop elements are required to control pressure pulsations. Can there be a balance between the pulsation control benefits of pressure drop elements and the need to meet NPSHA? This paper is of interest to designers and engineers working with reciprocating pump installations. It aims at challenging industry resistance to using pressure drop elements in the suction piping of reciprocating pumps by, first, outlining the virtues achieved in terms of pulsation and vibration control, and second, presenting results from numerical simulations (one-dimensional pulsation and detailed CFD modelling). Recent field data from a quintuplex pump installation were used to validate the 1-D pulsation model.  The results show that well-designed orifice plates, and other pressure drop elements, are beneficial for reducing pulsations and cavitation risks; and can be used in the suction piping of reciprocating pumps.Objective• Demonstrate that proper use of orifice plates and other pressure drop elements (choke tubes and line-size reductions) in the suction piping of reciprocating pumps are beneficial for pulsation control and mitigation of cavitation risks.Analysis approach• Field-measured pulsations and numerical simulations (1-D pulsation model and CFD modelling). Contents1. Author bios2. Abstract3. Contents4. Objective5. Introduction6. 1-D model 7. CFD model8. Validation of 1-D model 9. 1-D model results10. Definition of pressure loss terms 11. Average pressure loss: 1-D vs CFD 12. Total pressure loss: 1-D vs CFD 13. CFD visualization: pressure recovery14. ConclusionsIntroduction• Reciprocating pumps:– Widespread use in industry– Generate pressure pulsations– Uncontrolled pulsations  vibrations, cavitation, failures• Orifice plates:– Reduced pressure under-spikes  lower cavitation risk – Pressure drop  reduced NPSHA  higher cavitation risk  Introduction, continued– Two 5-plunger propane pipeline pumps; 3.5” bore x 5” stroke – 160 – 400 RPM, 416 GPM/pump; Ps = 98 – 282 psig; Pd = 1100 psig– Elevated and inadequately supported piping– High pulsations, vibrations and indications of cavitation – Winter condition worse than summer due to higher liquid bulk modulus– NDT showed several cracks in piping after six months of operationCase study pump installation:1-D model• Applied method of characteristics to solve 1-D fluid dynamics equation • Used empirical loss factors to calculate irreversible pressure losses• Modelled from pump valves to known boundaries in piping0o144o216o72o288oPlunger phasingBC: Velocity profile at the pump valvesCrank cycles- Velocity peak from average flow rate.- CFD: sinusoidal wave-form. No valve delay.1-D model, continuedPump suction: original design(limited space)1-D model, continuedPump suction: modified design3.125” ID orifice plateValidation of 1-D model• Field: pulsations measured at Node 182• Field data vs 1-D model:– Field visit during summer– Frequency spectra at 300 RPM– Frequency spectra at 165 – 300 RPMValidation of 1-D model, continuedPulsations at node 180 (without orifice plate installed)Summer conditionSingle speedSpeed sweepPressure (psi pk)1-D model resultsKey result: Orifice plate will improve reliability. Operator concerned with pressure drop.Summer conditionWinter conditionPulsations at Node 145145Pulsations at Node 145Without orificeWith orificeWithout orificeWith orifice~ 40% reduction~ 20% reduction• Solved 3-D Navier-Stokes equation• Modelled from pump valves to small part of suction piping• Assumed ideal pump valve opening and closing (no valve delays)• BC: velocity profile at valves; constant pressure at suction pipe• Turbulence model: → Large-eddy simulation (LES) → Wall adapting local eddy-viscosity (WALE)• Used reduced 1-D model for comparisonswith CFD modelCFD modelConstant pressure (open end termination)Sinusoidal velocity profile at pump valves3.125” ID orifice plateDefinition of pressure loss terms• ∆Pavg : Average pressure loss• ∆Pmax : Maximum pressure loss• ∆Pcav : Pressure loss for cavitation• Po : Static pressure at pump inlet• Pavg       : Time-average static pressure (time: ~ 2 sec.)• Pv:      : Vapour pressure 𝑃𝑃PoPvPavg∆Pavg∆Pmax ∆PcavPressure without orifice platePressure with orifice plateAverage pressure loss: 1-D vs CFD model1D Model CFD modelCase 1: Without Orifice PlateCase 2: With Orifice Plate{Pressure recovered• The same geometry for 1-D and CFD models• Average pressure loss (recoverable + irreversible)→ Effect of pulsations not included→ Higher loss with orifice plate→ Pressure recovery with CFD modelTotal pressure loss: 1-D vs CFD modelCase 1: no orifice plate{Pressure recoveredCase 2: with orifice plate• Maximum pressure loss (pulsations + recoverable + irreversible)→ Mainly due to pulsations→ Higher with orifice plate→ Pressure recovery with CFD model→ Same trend in both models.  Increases towards closed endKey result: • Average pressure loss in 1D model is irreversible (no pressure recovery)→ more conservativeCFD visualization: pressure recovery               CFD animation with orificeCFD animation without orificeConclusions• 1D pulsation model validated with field data: good agreement• Predicted pressure losses consistent between 1-D and CFD models• CFD simulation provided more information, incl recovered pressure loss• Well-designed orifice plates and other pressure drop elements:→ Are beneficial for reducing pulsations, vibrations and cavitation risks→ Can be used in the suction piping of reciprocating pumps if properly sized for mean and dynamic pressure losses• Orifices not yet implemented - more validation needed (ongoing)

Benefits of Installing Restrictive Orifice Plates On the Suction of Reciprocating Pumps:1D Pulsation and CFD Studies

Texas A&M University

Benefits of Installing Restrictive Orifice Plates 
on the Suction of Reciprocating Pumps:
1D Pulsation and CFD Studies
Presenter: 
Kelly Eberle, PEng, Principal Consultant, 
Wood 
Presenter/author bios
Zixiang Chen, Wood Group (formerly BETA Machinery Analysis), PhD, EIT, Engineer – Zixiang has recently completed his doctoral 
work in the field of fluid dynamics. His academic research interest is on the sensor-based estimation of large-scale coherent 
structures in turbulent flows using optical flow diagnostics and numerical simulations. Prior to joining Wood Group in 2014, he 
worked on combustion modelling for the GT24/26 and compressor aerodynamics for the PT6.
Cajetan Ijeomah, Wood Group (formerly BETA Machinery Analysis), MSc, PEng, Senior Engineer
Cajetan is a professional engineer with over 14 years of industry experience, the majority of which is in dynamic engineering and 
vibration design. His responsibilities include acoustical (pulsation), mechanical and thermal analysis of reciprocating compressor 
and pump systems, evaluation of piping systems and related dynamic studies. Cajetan manages complex design projects involving
multiple vibration disciplines and is proficient in the use of various engineering analysis software tools.
Jordan Grose, Wood Group (formerly BETA Machinery Analysis), PEng, MBA, Service Leader – Americas
Jordan is a mechanical engineer with extensive domestic and international design, field, and monitoring experience with 
compressors, pumps, pipelines, and other production machinery. He has specialized skills in vibration, liquid transient analysis, 
performance, and troubleshooting in onshore and offshore production facilities. 
Jordan currently leads Wood Group’s vibration integrity group in addressing plant-wide vibration risks in piping and machinery 
systems. He has been with Wood Group (formerly BETA Machinery Analysis) for over 14 years, during which time he has authored 
and co-authored several papers. Jordan was formerly responsible for BETA’s Malaysia office in Kuala Lumpur. 
Kelly Eberle, Wood Group (formerly BETA Machinery Analysis), BSc, PEng, Principal Consultant 
Kelly is a principal consultant and has been with Wood Group (formerly BETA Machinery Analysis) since 1988. He has accumulated 
a wide range of design and field experience, particularly in the area of pressure pulsation analysis and mechanical analysis of 
reciprocating compressor and pump installations. The scope of his experience includes pulsation simulations, thermal flexibility
studies, dynamic finite element analysis, structural analysis and foundation analysis.
Abstract
It is well understood that static pressure at the inlet of reciprocating pumps, quantified typically by Net Positive Suction 
Head Available (NPSHA), must be sufficient to avoid cavitation in the pump suction manifold and chamber. In an effort to 
conserve NPSHA, pump designers generally rely on rules of thumb that resist the addition of pressure drop elements such 
as restrictive orifice plates, choke tubes and line-size reductions to the inlet piping of all pumps, including reciprocating 
pumps. 
Another design consideration of reciprocating pumps is the generation of pressure pulsations due to pump piston and valve 
motion. Uncontrolled pulsations can result in cavitation and vibration-related fatigue failures. In many cases, pressure drop 
elements are required to control pressure pulsations. Can there be a balance between the pulsation control benefits of 
pressure drop elements and the need to meet NPSHA? 
This paper is of interest to designers and engineers working with reciprocating pump installations. It aims at challenging 
industry resistance to using pressure drop elements in the suction piping of reciprocating pumps by, first, outlining the 
virtues achieved in terms of pulsation and vibration control, and second, presenting results from numerical simulations 
(one-dimensional pulsation and detailed CFD modelling). Recent field data from a quintuplex pump installation were used 
to validate the 1-D pulsation model.  The results show that well-designed orifice plates, and other pressure drop elements, 
are beneficial for reducing pulsations and cavitation risks; and can be used in the suction piping of reciprocating pumps.
Objective
• Demonstrate that proper use of orifice plates and other 
pressure drop elements (choke tubes and line-size reductions) 
in the suction piping of reciprocating pumps are beneficial for 
pulsation control and mitigation of cavitation risks.
Analysis approach
• Field-measured pulsations and numerical simulations (1-D 
pulsation model and CFD modelling). 
Contents
1. Author bios
2. Abstract
3. Contents
4. Objective
5. Introduction
6. 1-D model 
7. CFD model
8. Validation of 1-D model 
9. 1-D model results
10. Definition of pressure loss terms 
11. Average pressure loss: 1-D vs CFD 
12. Total pressure loss: 1-D vs CFD 
13. CFD visualization: pressure recovery
14. Conclusions
Introduction
• Reciprocating pumps:
– Widespread use in industry
– Generate pressure pulsations
– Uncontrolled pulsations 
 vibrations, cavitation, failures
• Orifice plates:
– Reduced pressure under-spikes  lower cavitation risk 
– Pressure drop  reduced NPSHA  higher cavitation 
risk  
Introduction, continued
– Two 5-plunger propane pipeline pumps; 3.5” bore x 5” stroke 
– 160 – 400 RPM, 416 GPM/pump; Ps = 98 – 282 psig; Pd = 1100 psig
– Elevated and inadequately supported piping
– High pulsations, vibrations and 
indications of cavitation 
– Winter condition worse than summer 
due to higher liquid bulk modulus
– NDT showed several cracks in piping 
after six months of operation
Case study pump installation:
1-D model
• Applied method of 
characteristics to solve 
1-D fluid dynamics 
equation 
• Used empirical loss 
factors to calculate 
irreversible pressure 
losses
• Modelled from pump 
valves to known 
boundaries in piping
0o
144o
216o
72o
288o
Plunger phasing
BC: Velocity profile at the pump valves
Crank cycles
- Velocity peak from average flow rate.
- CFD: sinusoidal wave-form. No valve delay.
1-D model, continued
Pump suction: original design
(limited space)
1-D model, continued
Pump suction: modified design
3.125” ID orifice plate
Validation of 1-D model
• Field: pulsations measured at Node 182
• Field data vs 1-D model:
– Field visit during summer
– Frequency spectra at 300 RPM
– Frequency spectra at 165 – 300 RPM
Validation of 1-D model, continued
Pulsations at node 180 (without orifice plate installed)
Summer condition
Single speed
Speed sweep
Pr
es
su
re
 (p
si 
pk
)
1-D model results
Key result: 
Orifice plate will improve reliability. 
Operator concerned with pressure drop.
Summer conditionWinter condition
Pulsations at 
Node 145
145
Pulsations at 
Node 145
Without orifice
With orifice
Without orifice
With orifice
~ 40% 
reduction
~ 20% 
reduction
• Solved 3-D Navier-Stokes equation
• Modelled from pump valves to small part of suction piping
• Assumed ideal pump valve opening and closing (no valve delays)
• BC: velocity profile at valves; constant pressure at suction pipe
• Turbulence model: 
→ Large-eddy simulation (LES) 
→ Wall adapting local eddy-viscosity (WALE)
• Used reduced 1-D model for comparisons
with CFD model
CFD model
Constant pressure 
(open end termination)
Sinusoidal velocity 
profile at pump valves
3.125” ID 
orifice plate
Definition of pressure loss terms
• ∆Pavg : Average pressure loss
• ∆Pmax : Maximum pressure loss
• ∆Pcav : Pressure loss for cavitation
• Po : Static pressure at pump inlet
• Pavg       : Time-average static pressure 
(time: ~ 2 sec.)
• Pv:      : Vapour pressure 𝑃𝑃Po
Pv
Pavg
∆Pavg
∆Pmax ∆Pcav
Pressure without orifice plate
Pressure with orifice plate
Average pressure loss: 1-D vs CFD model
1D Model CFD model
Case 1: Without Orifice 
Plate
Case 2: With Orifice 
Plate
{
Pressure recovered
• The same geometry for 1-D and CFD models
• Average pressure loss (recoverable + irreversible)
→ Effect of pulsations not included
→ Higher loss with orifice plate
→ Pressure recovery with CFD model
Total pressure loss: 1-D vs CFD model
Case 1: no orifice plate
{
Pressure recovered
Case 2: with orifice plate
• Maximum pressure loss 
(pulsations + recoverable + irreversible)
→ Mainly due to pulsations
→ Higher with orifice plate
→ Pressure recovery with CFD model
→ Same trend in both models. 
 Increases towards closed end
Key result: 
• Average pressure loss in 1D model is 
irreversible (no pressure recovery)
→ more conservative
CFD visualization: pressure recovery
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
CFD animation 
with orifice
CFD animation 
without orifice
Conclusions
• 1D pulsation model validated with field data: good agreement
• Predicted pressure losses consistent between 1-D and CFD models
• CFD simulation provided more information, incl recovered pressure loss
• Well-designed orifice plates and other pressure drop elements:
→ Are beneficial for reducing pulsations, vibrations and cavitation risks
→ Can be used in the suction piping of reciprocating pumps 
if properly sized for mean and dynamic pressure losses
• Orifices not yet implemented - more validation needed (ongoing)


https://oaktrust.library.tamu.edu/bitstream/1969.1/166760/1/06_Chen.pdf

Benefits of Installing Restrictive Orifice Plates On the Suction of Reciprocating Pumps:1D Pulsation and CFD Studies

Abstract

Similar works

Full text

Available Versions

Texas A&M Repository

Texas A&M University

Benefits of Installing Restrictive Orifice Plates On the Suction of Reciprocating Pumps:1D Pulsation and CFD Studies

Abstract

Similar works

Full text

Available Versions

Texas A&amp;M Repository

Texas A&M University

Texas A&M Repository