Water for irrigation, domestic and industrial supply as well for some power generation is normally drawn directly from rivers or from reservoir through sumps. The flow at the pump section sump may have large effects on the pump performances and the operating conditions. The flow patterns in the sump are mainly determined by the shape and scale of the sump. However, it’s not always possible to design a sump pump to provide uniform and stable flow to pumps, due to site constraints. For example in some cases air entraining (surface and subsurface vortex) occurs. These vortices may reduce pump performances and lead to increase plant operating costs. It becomes essential to investigate the pump sump to avoid these non uniformities inlet flow problems. Two approaches (experimental and numerical) are generally followed for such investigation. The numerical approach usually used solves the Reynolds averaged Navier-Stokes (RANS) equations with a near-wall turbulence model. In the validation of this numerical model, emphasis was placed on the prediction of the number, the location, the size and the strength of the various types of vortices. A previous study done by the same hauteur of this one [1], has shown the influence on a single type of mesh with different cell numbers, different intake pipe depths and different water levels, for two turbulence models closure. The present paper mainly focuses, first, on the effect of pump intake location in the sump and secondly on the effect of several inlet velocity gradients at inlet sump section

BAYEUL-LAINE, Annie-Claude

BOIS, Gérard

ISSA, Abir

English

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Abir ISSA, Annie-Claude BAYEUL-LAINE, Gérard BOIS - Numerical study of the influence of
Geometrical Parameters on flow in water Pump-Sump - In: Conference on Modelling Fluid Flow
(CMFF’09), Hungary, 2009-09-09 - Conference on Modelling Fluid Flow (CMFF’09) The 14th
International Conference on Fluid Flow Technologies - 2009
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Conference on Modelling Fluid Flow (CMFF’09) 
The 14th International Conference on Fluid Flow Technologies 
Budapest, Hungary, September 9-12, 2009 
NUMERICAL STUDY OF THE INFLUENCE OF GEOMETRICAL 
PARAMETERS ON FLOW IN WATER PUMP-SUMP 
Abir ISSA1, Annie-Claude BAYEUL-LAINẺ 2, Gérard BOIS3 
 
1 Arts et Métiers ParisTech, LML, UMR CNRS 8107, 8 Boulevard Louis XIV 59046 Lille Cedex, France Fax: +33 20 53 55 93. E-mail: 
issa@etudiants.ensam.fr 
2 Arts et Métiers ParisTech, LML,  E-mail: annie-claude.bayeul@ensam.eu 
3 Arts et Métiers ParisTech, LML,  E-mail: gerard.bois@ensam.eu 
 
ABSTRACT  
Water for irrigation, domestic and industrial 
supply as well for some power generation is 
normally drawn directly from rivers or from 
reservoir through sumps. 
      The flow at the pump section sump may have 
large effects on the pump performances and the 
operating conditions. The flow patterns in the sump 
are mainly determined by the shape and scale of the 
sump. However, it’s not always possible to design a 
sump pump to provide uniform and stable flow to 
pumps, due to site constraints. For example in some 
cases air entraining (surface and subsurface vortex) 
occurs. These vortices may reduce pump 
performances and lead to increase plant operating 
costs. 
        It becomes essential to investigate the pump 
sump to avoid these non uniformities inlet flow 
problems. Two approaches (experimental and 
numerical) are generally followed for such 
investigation. 
 The numerical approach usually used solves 
the Reynolds averaged Navier-Stokes (RANS) 
equations with a near-wall turbulence model. In the 
validation of this numerical model, emphasis was 
placed on the prediction of the number, the location, 
the size and the strength of the various types of 
vortices. 
A previous study done by the same hauteur of 
this one [1], has shown the influence on a single 
type of mesh with different cell numbers, different 
intake pipe depths and different water levels, for 
two turbulence models closure. 
 The present paper mainly focuses, first, on the 
effect of pump intake location in the sump and 
secondly on the effect of several inlet velocity 
gradients at inlet sump section. 
Keywords: CFD, free surface vortex, submerged 
vortex.  
NOMENCLATURE  
C [m] clearance distance from floor  
D [m] pipe intake diameter  
H [m] water level in the sump-pump 
L [m] the Pump-sump length 
S  [m] submergence depth for the pipe 
U [m/s] mean velocity in the sump 
V [m/s] mean velocity in the intake pipe  
W [m] pump-sump width 
g [m/s2] acceleration due to gravity 
k [m2/s2 ] turbulence kinetic energy 
ν [m2/s] kinematic viscosity 
ω [s-1] specific dissipation rate 
ρ [kg/m3] water density. 
σ [N/m] coefficient of surface tension  
Fr  Froude number for the pipe submergence  
Re Reynolds number in the pipe 
We Weber number 
1. INTRODUCTION  
It’s essential to design a sump pump that can 
provide fairly uniform and free vortices flow to the 
pumps. However, it’s not always possible, due to 
geometrical site specific constraints, which may 
cause a poor design of the intake. 
Low intake submerged depth could also results 
in the formation of the air entraining free surface 
vortices that could as well promote cavitation, [2]. 
Non uniform inlet flow field at sump entrance 
even far from pump intake section can also leads to 
accumulative effects due to 3D boundary layers 
development on the side-wall creating corners 
vortices that can be strength by local strong 
streamline curvature when approaching pump 
intake. 
All these non uniformities may create flow 
instabilities, vibrations and other undesirable 
phenomena that can cause operating difficulties and 
frequent maintenance of the whole pump 
arrangements. 
Melville et al. [2] have listed the main 
geometrical parameters that could influence the 
flow pattern in sump pump (Figure 1): submergence 
of the pump intake pipe(S), floor clearance(C), 
width clearance (l), back wall clearance(x1). As well 
non-dimensional cinematic parameters include: 
- Reynolds number in the intake pipe Eq. (1) 
 
ν
VDRe =  (1) 
 
- Froude number of the submerged Eq. (2) 
 
gS
UFr =  (2) 
 
- The Weber number, Eq. (3)  
 
σ
DVWe ρ
2
=  (3) 
 
Experimental investigations have been 
performed on physical scale model to reduce non 
uniformities of specific flow and geometrical 
conditions ([3] to [6]). More basic studies have been 
also conducted to establish empirical criteria for 
vortex formation and avoidance, ([7] to [9]). 
Over the past 15 years, modeling sumps by 
using CFD has remarkably developed to evaluate 
the flow around suction pipe intake in the sump, 
and contribute to the advancement of the knowledge 
about vortices formation, swirl, and pre-rotation. 
Tagomori and Gotoh [10] have used a finite volume 
method to solve the RANS equations with the (k-ε) 
turbulent model, in order to study the effects of non 
uniform inlet flow on vortex generation and the 
effects of additional devices to prevent vortical flow 
formation. Takata et al. [11] use large eddy 
simulations of pump intake flows at low Reynolds 
number (104). More recently, CFD benchmarks 
have been performed by Matsui et al. [12] in order 
to compare different software results with 
experiments. 
Constantinescu and Patel [13] have developed a 
CFD model to solve RANS equations and two 
turbulence model equations in order to simulate the 
flow in the sump; than they valued their results by 
experience.  
Both of laboratory experimental results and 
numerical data from sump pump modeling show 
that the vortices (size, form, location, and strength) 
depend on the pipe location in the sump and the 
pump sump geometry itself.   
2. BACKGROUND 
In a rectangular sump configuration, 
Constantinescu and Patel [13], reported that the 
strength of vortices increases with increase of 
vorticity in the approach flow; the intensity of the 
free surface and floor-attached vortices increases 
with asymmetry in the approach flow in the 
horizontal plane; the intensity of the side-wall 
attached vortices grows with asymmetry in the 
approach flow in the vertical plane; back-wall and 
corner vortices are due to secondary flows; the 
intensity of floor-attached vortices decreases while 
that of side-wall and back-wall vortices increases as 
the floor clearance is increased. 
 There is a general agreement among the 
various studies that free-surface vortices are 
observed as the submergence decreases and air-
entraining vortices appear at low submergence. This 
last aspect has been recently studied and reported 
by Shula and Kshirsagar [14]. 
J. Matsui and Kamemoto [12], have analyzed 
the simulation of the flow in a standard pump sump 
by 5 groups with various codes, grids, and methods. 
These results are compared with the experimental 
result by PIV measurement. The distribution of 
vorticity is different in each CFD results. Numerical 
method, turbulent model, grid numbers, and grid 
shape may change the vorticity largely. 
In previous paper [1] the study has been 
focused on the submergence effect with the intake 
pipe always located in the middle in the sump 
width. This study also demonstrated that, the 
vorticity level becomes greater when the 
submergence decreases. 
The aim of this paper is to complete 
numerically the previous study done ([1]), in order 
to evaluate the effect of: 
Firstly: asymmetric location of the pipe in the 
sump for uniform upstream condition (case I) 
Secondly: Two different non-uniform inlet flow 
conditions at the inlet horizontal plane, for 
symmetric location of the pipe. (cases II and III). 
3. SUMP GEOMETRY AND TEST CASES 
The intake geometry used for the calculations is 
sketched in Fig.1.  
 
in
let
pl
an
e 
ve
rti
ca
l
x
flowz
D
outlet plane
flow
S
C
H
in
let
 pl
an
e 
ho
riz
on
ta
l
x1 x2
l 
x
y
flow
l1
l2
+w
-w
 
 
Figure 1. Pump-sump shape and geometrical 
It is based on the Constantinescu and Patel’s 
one ([13]). It consists of a rectangular sump with an 
intake pipe of diameter D=0.1m. It’s to note that the 
intake pipe is placed at a fixed value from the back 
wall(x1=0.9D). The level of all water in the sump 
still constant (C=0.75D-S=2D) for all tests. As well 
the mean velocity in the pipe which is equal to 
V=0.286m/s. 
The channel inlet is situated (x2=6,5D) 
upstream the pipe axis, and the length of the intake 
pipe is equal to 8D 
As already said, two configurations have been 
chosen for the present study. For case I, the intake 
pipe is located asymmetrically in the sump pump 
according to x axis like l1=D, l2=1.6D, and the 
feeding at the inlet of sump is uniform (Fig. 1). 
For the two other cases, the intake pipe is 
located at the middle of the sump width (Fig. 2).  
 
 
 
Figure 2. Pump-sump shape feeding non-
uniform 
 
Modified inlet conditions create a non uniform 
inlet flow condition in y direction depending on Ф 
angle values as shown in Table 1. The velocity 
profile obtained for case III at x=3D, is shown in 
Fig. 3. 
Table 1. Cases studied for feeding asymmetrical 
Cases x3 L3 Ф 
II D D 45° 
III D 0.5D 26.6° 
 
‐0,15
‐0,1
‐0,05
0
0,05
0,1
0,15
0 0,01 0,02 0,03 0,04
W
 (m
)
Velocity (m/s)
Velocity
 
Figure 3. The inlet velocity at x=3D 
 
 
4. GRID AND CALCULATIONS 
The calculation domain is mainly divided into 3 
blocks, as illustrate in Fig. 4. The first block 
presents the part of sump which is below the intake 
pipe, the second one is the rest of sump which 
includes the submergence pipe intake, assuming an 
infinity thin pipe wall, and the last one contains the 
upper part of pipe up to the free surface. The 
resulting computational grid is a structured 
hexahedral grid with 592050 cells, for case I. 
For cases II and III, two blocks grid was added 
in order to modify the inlet of the sump as sketched 
in Fig. 5 as an example.  A total of 59800 cells for 
case II and 60500 cells for case III have been 
reached. 
For all cases tested, the values of non 
dimensional numbers are: Re= 28600, We=114 and 
Fr=0.023. The free surface is considered as a 
symmetrical condition. Hydrostatic pressure is 
assumed constant in the inlet plan, and the velocity 
is imposed in the outlet plane of the pipe. In this 
study, the flow field of pump sump is assumed to be 
steady state and is solved by using a commercial 
code FLUENT using the turbulent model (k-ω).  
 
 
 
     
 
Figure 4. Grid for case I  
                                                  
     
 
 
 
Figure 5. Grid for case II 
5. PRESENTATION OF RESULTS 
Two types of results are presented. First of all a 
global overview of streamlines issued from free 
surface sump are given in figures 6 to 8 for the three 
test cases I, II and III respectively. It has to be 
noticed that the streamline patterns obtained for 
case I looks like case II or II but on the opposite 
side. Secondly, the vorticity contours and tangential 
velocity component contours, for different 
increasing levels of z inside the inlet intake pipe, are 
presented in Figs. 9 to 16 for case I, Figs. 17 to 24 
for case II and in Figs. 17 to 24 for last case III. 
 
6. DISCUSSION  
For case I, the vorticity field has both negative 
and positive values at first z location as shown in fig 
9. Negative values extend more than the positive 
ones and only negative values remain for increasing 
z positions inside the pump inlet pipe (figs. 10 to 
12). The tangential velocity contours presented in 
figs. 13 to 16 show a clockwise tangential velocity 
evolution.  
For case II, and because of the opposite 
streamline structure already seen in figures 7 and 8 
compared to figure 6, the vorticity field still have 
both positive and negative values at first z location 
as shown in figure 17. Now, compare to case I, only 
positive values remain for increasing z positions 
inside the pump inlet pipe (figs 18 to 20). These 
evolutions can also be seen looking at tangential 
velocity contours on figs 21 to 24. 
Maximum tangential velocities reach a 
maximum value of about 30 per cent of mean 
velocity V inside the pipe. 
Except first z location where both positive and 
negative tangential velocities still remain, flow 
mainly got a counter clockwise rotation inside the 
pump inlet pipe with expected decreasing values of 
tangential velocities for increasing z locations due 
to wall friction. These results show that, among the 
two main swirls that can be observed from free 
surface, the strongest one corresponds to the swirl 
created because of inlet velocity gradient. This is 
confirm looking at figure 8 and figures 25 to 32 
corresponding to test case III for which the inlet 
velocity field creates a counter clockwise vortex 
similar to case II but stronger due to stronger 
velocity gradient as shown in figure 3. The more the 
inlet gradient is strong, the more tangential velocity 
remains inside the pipe. More detailed 
investigations show that the inlet pipe velocity field 
is more sensitive to inlet velocity field than 
asymmetric tube position in the sump such as case I 
configuration. 
 
 
         
Figure 6. Streamline at the free surface-case I 
 
 
 
Figure 7. Streamline at the free surface-case II 
 
 
 
Figure 8. Streamline at the free surface-case III 
 Figure 9. Vorticity-z=0.075D-case I  
 
Figure 10. Vorticity-z=0.125D-case I 
 
Figure 11 Vorticity-z=0.175D-case I  
 
Figure 12. Vorticity-z=0.25D-case I  
 
Figure 13. Tangential Velocity-z=0.075D-case I 
 
Figure 14. Tangential Velocity-z=0.125D-case I  
 
Figure 15. Tangential Velocity-z=0.175D-case I  
 
Figure 16. Tangential Velocity-z=0.25D-case I  
 
 Figure 17. Vorticity-z=0.075D-case II 
 
Figure 18. Vorticity at z=0.125D-case II 
 
Figure 19. Vorticity-z=0.175D-case II 
 
Figure 20. Vorticity-z=0.25D-case II 
 
Figure 21. Tangential Velocity-z=0.075D-case II 
 
Figure 22. Tangential Velocity-z=0.125D-case II 
 
Figure 23. Tangential Velocity-z=0.175D-case II 
 
Figure 24. Tangential Velocity-z=0.25D-case II 
 
 Figure 25. Vorticity-z=0.075D-case III 
 
Figure 26. Vorticity at z=0.125D-case III 
 
Figure 27. Vorticity-z=0.175D-case III 
 
Figure 28. Vorticity-z=0.25D-case III 
 
Figure 29. Tangential Velocity-z=0.075D-case III 
 
Figure 30. Tangential Velocity-z=0.125D-case III 
 
Figure 31. Tangential Velocity-z=0.175D-case III 
 
Figure 32. Tangential Velocity-z=0.25D-case III 
 
 
7. CONCLUSION 
3D flow calculations have been performed on a 
sump configuration in order to evaluate the 
sensitivity on both asymmetric geometrical and 
velocity field configuration on the inlet intake pipe. 
 This study complete a previous one already 
published for which other parameters have been 
studied for symmetrical configurations. Numerical 
results show that a slight modification on inlet flow 
conditions can have a relative strong effect on the 
incoming flow pattern inside the pump intake pipe. 
This may create tangential velocity inlet flow 
conditions that cannot be easily damped even with 
modified sump configuration that can be sometime 
seen. This also means that it will be very difficult to 
analyse such flows in research configuration if one 
wants to compare experiments and calculations for 
example for uniform inlet flow conditions which are 
difficult to obtain in an experimental set up. 
REFERENCES 
 
[1] Abir Issa, Annie-Claude Bayeul-Lainé, Gérard 
Bois , 2008, “Numerical Simulation of Flow 
Field Formed in Water Pump-Sump”, 24h 
Symposium Hydraulic Machinery Systems. 
Bresil. 
[2] Melville, B. W. Ettema, R., and Nakato, T. 
1994, “Review of flow problems at water intake 
Pump Sumps”, EPRI Res. Proj. PR3456-01 
Final Rep. Iowa Inst.of Hydr. THE Univ of 
Iowa. Iowa City. pp. II.61 - II.68. 
[3] Nakato, T. 1988, “Hydraulic-Labortatory 
Model  Studies of  the Circulation-Water 
Pump-Intake Structure, Florida Power 
Corporation, Crystal River. Units 4 and 5”, 
IIHR Rep. No.320,  Iowa Inst.of Hydr. THE 
Univ of Iowa. Iowa City.  
[4] Nakato, T. 1989, “A Hydraulic-Model  Study of  
the Circulation-Water Pump-Intake Structure”, 
Laguna Verde Nuclear Power Station, Unit. 1, 
Comision Federal De Electrcidad. IIHR Rep. 
No.330,  Iowa Inst.of Hydr. The Univ of Iowa. 
Iowa City 
[5] Nakato, T. 1990, “A Hydraulic-Model Study of  
the Proposed Pump-Intake and Discharge 
Flume Crystal River Cooling-Tower Project”, 
IIHR Rep.  No.339, Iowa Inst.of Hydr. THE 
Univ of Iowa. Iowa City  
[6] Ettema, R., and Nakato, T, 1990, “Hydraulic- 
Model  Study of  the Circulation-Water and 
Essential-Service-Water Pump-Intake 
structures:  Korea Electric Power Corporation 
Yonggwag Station, Units 3 and 4”, IIHR 
Limited Distribution Rep. No.339, Iowa Inst.of 
Hydr. THE Univ of Iowa. Iowa City. Iowa. 
[7] Anwar, H. O., 1966, “Formation of a Weak 
Vortex” J. Hydr. Res., 4(1), 1-16 
[8] Anwar, H. O., and Amphlett, M. B., 1980, 
“Vortices at Vertically in Verted Intake”, J. 
Hydr. Res., 18(2), 123-134 
[9] Daggett, L. L., and Keulegan, G. H., 1972, 
“Similitude Conditions in Free Surface Vortex 
Formation”, J. Hydr. Div., ASCE. 100(11), 
1565-1580 
[10] Tagamori, M.,and Gotoh, M., 1989, “ Flow  
Patterns and Vortices in pumps sumps” Proc., 
Int. Symp. Large Hydr. Machienry.China Press, 
Beijing. China, 13-22 
[11] Takata, I., Kawata, Y., Kobayashi, T., and 
Morinishi, Y., 1992, “Large-Eddy Simulation 
of Unsteady Turbulent Swirl Flow in a pump 
Intake”, 1 st Computational Fluid Dyn. Eur. 
Conf., Elsevier Applied Science, New York, 
255-261 
[12] Matsui, J., Kamemoto, K., and Okamura. T., 
2006,” CFD Benchmrak and a Model 
Experiment on the Flow in Pump Sump”. 23TH 
Symposuim. Yokohama. 1(10)-(16) 
[13] Constantineascu, G., and Patel, V. C., 1998, 
”Numerical Model for Simulation of Pump 
Intake Flow and Vortices”. Jounal of hydraulic 
Engineering. Div, ASCE, vol 124, 123-134. 
Iowa Inst of Hydr Res. The Univ of Iowa. Iowa 
City, Iowa. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 


Numerical study of the influence of Geometrical Parameters on flow in water Pump-Sump

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Numerical study of the influence of Geometrical Parameters on flow in water Pump-Sump

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