modelling of pumping unit cummins presentation · 2016-07-01 · introduction (contd.) the pumping...

1D Modelling of Pumping Unit of Liquid-Only Urea Dosing System using GT-SUITE

Abhishek Nerkar

Thomas Betz

Dr. Kay Schmidt

Dr. Brijesh Patel

7th December 2015

Outline

�Introduction

�Objective of the Work

�Work Flow

�Modelling of the Pumping Unit

�Validation of the Model

�Useful Information from the Model

�Conclusions

2

Introduction

3

� The future emission norms stringent

nitrogen oxide (NOx) coming out from

the engines

� A well-known trade-off between NOx

and PM is reported with in-cylinder

emission reduction techniques. Hence,

after-treatment reduction techniques are

also required to meet the upcoming

emission norms

� Selective catalytic reduction (SCR)

technique is generally used to reduce

NOx in N2 by reacting with ammonia

(NH3)

* Brijesh and Sreedhara, IJAT, Vol 14, 2013

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

PM

, g/k

m

NOx, g/km

EURO 1 (1994)

EURO 2 (1998)

EURO 3 (2000)

EURO 4 (2005)

EURO 5 (2009)EURO 6 (2014)

* Progression of European emission standards for

light commercial diesel vehicles

O6H4NO4NH4NO 2223 +→++

O12H7N8NH6NO 2232 +→+

O6H4N4NH2NO2NO 2232 +→++

Introduction (Contd.)� The pumping unit is an important

component of the urea dosing

system

� It makes sure a continuous supply of

the required quantity of urea, also

known as diesel exhaust fuel (DEF),

to the dosing unit

� Pumping unit is having a flexible

diaphragm type pump which creates

flow and desired pressure

� Hence, it is necessary to understand

the dynamic behaviour of the

pumping system

� The stiffness of the diaphragm

changes as a function of pump lift

and pressure on diaphragm which

makes it complex for modelling 4

Dosing unit of urea dosing system

Pumping unit of urea dosing system

Objective of the Work

�Modelling of the pumping unit of dosing systemusing 1D GT-Suite

�Validation of the model with the experimental data

�Study the effect of aeration in the system

�Study the dynamics of the pump valves

5

Work Flow

Flow Volumes (Extraction in GT-SpaceClaim)

Input Data

1D GT Model Validation

GT-Fuel-UL2-SU.mm

Experimental Test Rig

Flow Volumes (Discretization in GEM3D)

6

Su

cti

on

Pre

ssu

re (

ba

r)

Pump Diaphragm Position (degree)

Experimental_3

Simulation_3

Pu

mp

Ch

am

ber

Pre

ssu

re (

bar)


Experimental_3

Simulation_3

Modelling of the Pumping Unit

7

� Flow volumes have been extracted

using GT-SpaceClaim and modelled

using GEM3D

� Total change in volume inside the pump

chamber has been captured by

modelling stroke of diaphragm and

stiffness of diaphragm

� Pressure drop across suction-side filter

was modelled

� Co-efficient of discharge (Cd) at valves

were calculated from provided test data

� Main filter was modelled using variable

volume flowsplit

� Desired pressure in the pumping unit

was achieved with PID controller

� Air in system is modelled using Aeration

model

Validation of the Model

8

� Experimental test rig has a capability to

measure the pump chamber pressure

� Pump chamber pressure traces Vs pump

diaphragm position were generated to

understand the dynamic behavior of the

flexible diaphragm

� Suction pressure, outlet pressure and DEF

volume flow rate have also been

considered an important parameters for

validating the model

� Extensive test data for various operating

conditions (speed and pressure) have

been produced to validate the model Experimental Test Rig

Comparison of Pump Chamber Pressure

9

Pu

mp

Ch

am

ber

Pre

ssu

re (

ba

r)


Experimental_1

Simulation_1

Pu

mp

Ch

am

ber

Pre

ssu

re (

ba

r)


Experimental_2

Simulation_2

Pu

mp

Ch

am

ber

Pre

ssu

re (

ba

r)


Experimental_3

Simulation_3P

um

p C

ha

mb

er

Pre

ssu

re (

bar)


Experimental_4

Simulation_4

Pu

mp

Ch

am

ber

Pre

ssu

re (

ba

r)


Experimental_5

Simulation_5

� Simulation pressure trends are matching very well with experimental trends

� Peak pressure values are also predicting very close with the experimental values

10

Pu

mp

Ch

am

ber

Pre

ssu

re (

bar)


Experimental_6

Simulation_6

Pu

mp

Ch

am

ber

Pre

ssu

re (

bar)


Experimental_8

Simulation_8

Pu

mp

Ch

am

ber

Pre

ssu

re (

ba

r)


Experimental_9

Simulation_9

Pu

mp

Ch

mb

er P

ress

ure

(b

ar)


Experimental_7

Simulation_7

Comparison of Pump Chamber Pressure (Contd.)

� For higher RPM, simulation pressure trends are matching with one of the two

experimental pressure trends

Comparison of Suction Pressure

11

Su

ctio

n P

ress

ure

(b

ar)


Experimental_1

Simulation_1

Su

ctio

n P

ress

ure

(b

ar)


Experimental_2

Simulation_2

Su

cti

on

Pre

ssu

re (

ba

r)


Experimental_3

Simulation_3S

uct

ion

Pre

ssu

re (

ba

r)


Experimental_4

Simulation_4

Su

ctio

n P

ress

ure

(b

ar)


Experimental_5Simulation_5

� Simulation pressure trends are matching qualitatively with the experimental trends

Comparison of Suction Pressure (Contd.)

12

Su

ctio

n P

ress

ure

(b

ar)


Experimental_6

Simulation_6

Su

cio

n P

ress

ure

(b

ar)


Experimental_7

Simulation_7

Su

ctio

n P

ress

ure

(b

ar)


Experimental_8

Simulation_8

Su

ctio

n P

ress

ure

(b

ar)


Experimental_9

Simulation_9

� Similar to pump chamber pressure, suction pressure trends are predicting one of the

two experimental pressure trends

Ou

tlet

Pre

ssu

re (

bar)


Experimental_1

Simulation_1

Ou

tlet

Pre

ssu

re (

bar)


Experimental_2

Simulation_2

Ou

tlet

Pre

ssu

re (

bar)


Experimental_3

Simulation_3

Ou

tlet

Pre

ssu

re (

bar)


Experimental_4

Simulation_4O

utl

et P

ress

ure

(b

ar)


Experimental_5

Simulation_5

Ou

tlet

Pre

ssu

re (

bar)


Experimental_7

Simulation_7

Ou

tlet

Pre

ssu

re (

bar)


Experimental_8

Simulation_8

Ou

tlet

Pre

ssu

re (

bar)


Experimental_9

Simulation_9

Ou

tlet

Pre

ssu

re (

bar)


Experimental_6

Simulation_6

Comparison of Outlet Pressure

13

Less than 10%variation hasbeen observedbetweenexperimentaland simulationoutlet pressurevalues

14

Suction and Pressure Side Valve Lift

Useful Information from the Model

� Opening duration ofsuction valve isincreased with increasedpump speed

� On the other hand,pressure valve openingduration is decreasedwith increased speed

� It seems that both thevalves open withmaximum lift for alloperating speed

� Valves operation andchamber pressuretraces can be correlatedeasily

Va

lve

Lif

t (m

m)

Pu

mp

Ch

am

ber

Pre

ssu

re (

ba

r)


Pump chamber pressureValve lift_SuctionValve lift_Pressure

Case=1

Va

lve

Lif

t (m

m)

Pu

mp

Ch

am

ber

Pre

ssu

re (

ba

r)



Case=2

Va

lve

Lif

t (m

m)

Pu

mp

Ch

am

ber

Pre

ssu

re (

ba

r)



Case=3

Va

lve

Lif

t (m

m)

Pu

mp

Ch

am

ber

Pre

ssu

re (

ba

r)

Pump Chamber Position (degree)

Pump chamber pressure

Valve lift_Suction

Valve lift_Pressure

Case=4

15

Suction and Pressure Side Valve Lift (Contd.)

Useful Information from the Model (Contd.)

Va

lve

Lif

t (m

m)

Pu

mp

Ch

am

ber

Pre

ssu

re (

ba

r)



Valve lift_Suction

Valve lift_Pressure

Case=5

Va

lve

Lif

t (m

m)

Pu

mp

Ch

am

ber

Pre

ssu

re (

ba

r)



Valve lift_Suction

Valve lift_Pressure

Case=6

Va

lve

Lif

t (m

m)

Pu

mp

Ch

am

ber

Pre

ssu

re (

ba

r)



Valve lift_Suction

Valve lift_Pressure

Case=7

Va

lve

Lif

t (m

m)

Pu

mp

Ch

am

ber

Pre

ssu

re (

ba

r)



Valve lift_Suction

Valve lift_Pressure

Case=8

Va

lve

Lif

t (m

m)

Pu

mp

Ch

am

ber

Pre

ssu

re (

ba

r)



Valve lift_Suction

Valve lift_Pressure

Case=9

Conclusions

� 1D GT model of pumping unit predicts pump chamber pressure traces very

close with the experimental pressure traces. Hence, capture dynamic

behavior of the flexible diaphragm pump

� Outlet pressure and DEF volume flow rate are also predicted within 10%

variations

� Overall, it may be concluded that the 1D GT model has been validated well

with the experimental data

� Hence, the model quality can be considered to be acceptable and further

investigations will be performed based on this calibrated model

� Suction and pressure side valves dynamics can be easily understood with

the help of 1D GT model of pumping unit

16

Thank You

17

modelling of pumping unit cummins presentation · 2016-07-01 · introduction (contd.) the pumping...

Documents