Analysis of engine cooling waterpump of car & significance of its

International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –
6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 3, May - June (2013) © IAEME
100
ANALYSIS OF ENGINE COOLING WATERPUMP OF CAR &
SIGNIFICANCE OF ITS GEOMETRY
Bhavik M.Patel1
, Ashish J. Modi2
, Prof. (Dr.) Pravin P. Rathod3
1
(PG Student, Mechanical Engineering Department, Government Engineering College, Bhuj)
2
(Assistant Professor, Mechanical Engineering Department, Government Engineering
College, Bhuj)
3
(Associate Professor, Mechanical Engineering Department, Government Engineering
College, Bhuj)
ABSTRACT
To study behaviour of flow in cooling water pumps, we done extensive search and
gone through numerous research paper and blogs.We found that many researchers carried out
their analysis on other cooling system components like radiator, cooling water jacket and
fans. But it is very difficult to find researchers worked on cooling water pumps. However
cooling system consists of centrifugal pump which is widely used in other industry. After
reviewing all research paper on centrifugal pumps we found that most of the problems are
related to cavitationand low efficiency.Some researchers give importance to improvement of
blade angle and blade design to reduce cavitation effect while some researches concentrates
on efficiency of the pump irrespective of cavitation effect mostly in the industry where
cavitation effect is negligible. After analyzing some old water pumps of various vehicles we
found that major problem that pump is facing is due to cavitation effect on blades at High
RPM. This research is aimed to analyze the role of centrifugal water pump in automobile
engine cooling system and to obtain relation between pump geometry and pump flow
characteristics.
Keywords: Water pump, Engine cooling system, simulation, CFD, ANSYS, Cooling water
pump Geometry, cavitation, coolant flow, flow characteristics
INTERNATIONAL JOURNAL OF MECHANICAL ENGINEERING
AND TECHNOLOGY (IJMET)
ISSN 0976 – 6340 (Print)
ISSN 0976 – 6359 (Online)
Volume 4, Issue 3, May - June (2013), pp. 100-107
© IAEME: www.iaeme.com/ijmet.asp
Journal Impact Factor (2013): 5.7731 (Calculated by GISI)
www.jifactor.com
IJMET
© I A E M E

101
INTRODUCTION
Automobile Cooling pump is the key part of the Automobile cooling system that keep
circulate the coolant throughout it and takes away excess heat from engine at different Engine
rpm and torque conditions. Also it's surrounding atmospheric conditions can vary coolant
characteristics. This research involves the investigations on the existing coolant pump of car
(Maruti SUZUKI Alto), to understand the flow characteristics. The research is carried out in
three approaches to understand the behavior of fluid. The first one is "Theoretical approach"
in which Empirical relations are used. It describes how the desired pump operating
parameters such as flow rate, specific speed of pump etc. can be derived. It also describes the
coolant characteristics & understanding of flow characteristics in the closed, pressurized
automobile cooling system. The another one is "Practical approach" in which flow rate and
fluid pressure of pump flow are measured on existing coolant pump of Maruti SUZUKI Alto
at different engine rpm. The third approach involvesthe “Computational Fluid Dynamics" of
pump flow, which itself provides graphical representation of the relations between flow
characteristics and pump geometry. The "Result discussion" section provides brief discussion
on the results which are derived after these three approaches.
THEORITICAL APPROACH
Below steps has been carried out to obtain desired coolant flow rate.
• Obtained heat rejection data for specific engine model and rating. This information is
available from the engine technical data sheet. Maximum heat rejection (nominal +
tolerance) values are used.
• Obtained density and specific heat values for coolant. Table 1 provides these values
for the specific coolant.
• Using these values in Empirical equations we can calculate coolant flow rate as
below.
Heat Rejection by Engine Calculation
Before a coolant flow rate can be calculated, we must calculate how much heat is
being rejected through the engine. The heat input to the engine equals the sum of the heat and
work outputs. From following equation, heat input values are derived with the use of Power -
Torque - Speed curve. As per SAE papers, the total heat output of engine is the sum of total
exhaust heat, heat loss to the surroundings, total heat dissipated by engine coolant and total
heat dissipated by engine oil. It is also assumed that approximately one third of total heat
output is equal to the total heat dissipated by the engine coolant. The total heat input can be
calculated as follows:
Heat input to engineሺKWሻ ൌ
Brake PowerሺBPሻ ൈ 100
Thermal Efϐiciencyሺ%ሻ

International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976
6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 3, May
Coolant Flow Calculation
The coolant flow required for different heat load from the engine
can be calculated using the following equation:
Power - Engine RPM - Torque Curve
SAE 2001 paper states that conventional coolant flow rate on smaller engines with
mechanically driven water pumps vary between 2.0 to 2.6 L/min/Kw. The flow rate derived
from the above equation falls under this criteria.
curve based on above equations.
Specific Speed
Specific speed is a number characterizing the type of impeller in a unique and coherent
manner. Specific speed are determined independent of pum
comparing different pump designs. The specific speed identifies the geometrically similarity
of pumps.
Typical values for specific speed
• radial flow - 500 < Ns< 4000
vanes - double and single suction. Francis vane impellers in the upper range
• mixed flow - 2000 < Ns< 8000
pumps
• axial flow - 7000 < Ns< 20000
By calculation, the specific speed value falls between 1000
condition. So it suggestsusing radial vane impeller pump and the
cars also proves true that the car coolant pumps are centrifugal pumps with radial
6359(Online) Volume 4, Issue 3, May - June (2013) © IAEME
102
The coolant flow required for different heat load from the engine components to the radiators
can be calculated using the following equation:
Torque CurveRequired Pump RPM - Pump Flow Rate Curve
under this criteria. Graph 1 represents Pump rpm v/s flow rate
manner. Specific speed are determined independent of pump size and can be useful
Typical values for specific speed - Ns - for different designs in US units (US gpm, ft)
< 4000 - typical for centrifugal impeller pumps with radial
double and single suction. Francis vane impellers in the upper range
< 8000 - more typical for mixed impeller single suction
< 20000 - typical for propellers and axial fans
peed value falls between 1000-2000 under different operating
radial vane impeller pump and the actual pump used in existing
car coolant pumps are centrifugal pumps with radial
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 2000
PumpFlowRate(Kg/s)
Pump RPM
June (2013) © IAEME
components to the radiators
Pump Flow Rate Curve
Pump rpm v/s flow rate
p size and can be useful
(US gpm, ft)
typical for centrifugal impeller pumps with radial
double and single suction. Francis vane impellers in the upper range
more typical for mixed impeller single suction
under different operating
actual pump used in existing
car coolant pumps are centrifugal pumps with radial vanes.
2000 4000
Pump RPM

103
Typical Coolant Characteristics
The engine’s cooling system is designed to meet specific guidelines. The proper
coolant/antifreeze will provide the following functions:
• Adequate heat transfer
• Compatibility with the cooling system’s components such as hoses, seals, and piping
• Protection from water pump cavitation
• Protection from other cavitation erosion
• Protection from freezing and from boiling
• Protection from the build-up ofcorrosion, sludge, and scale
Following graph represents the Engine coolant saturation pressure at different fluid
temperature. Though cavitation is the phenomenon of "constant temperature boiling due to
low pressure" that is due to sudden increase in the fluid velocity at pump inlet when impeller
suck the fluid so there is sudden pressure drop of fluid. Table 1 show the coolant properties
when the fluid temperature is 80 deg. C.
Engine Coolant Saturation Pressure in psi Table 1
Pump Flow Characteristics
Pump inlet pressure is higher compare to saturation pressure at different temperature to
reduce cavitation effect at inlet side.
The cooling system and its components must meet both criteria.
A) Maximum pressure design limits. At any point in the cooling system that exceed the
maximum pressure for the local components such as radiators etc. and
B) The minimum pressure at any location in the cooling system shall not fall below the vapor
pressure of the coolant to prevent low pressure boiling. A minimum pressure/head is also
required at the pump inlet to avoid cavitation, minimize metal erosion and noise.
Coolant Property Value with
UNIT
Molar Mass 0.07343 Kg/mol
Density 1.03 Kg/m^3
Specific Heat 3579.71 J/Kg*K
Thermal
Conductivity
0.4153 W/m*K
Dynamic Viscosity 2.8 Centipoise
0
5
10
15
0 20 40 60 80 100 120
SaturationPressure(psi)
Temp in deg. C

104
PRACTICAL APPROACH
After determining the required coolant flow rate, pump performance establishes the
maximum allowable external resistance. Piping and heat transfer equipment resist water flow,
causing an external pressure head which opposes the engine driven pump. The water flow is
reduced as the external pressure is increases. The total system resistance must be minimized
in order to ensure adequate flow. A cooling system with excessive external pressure heads
will require pumps with additional pressure capacity. With Practical approach, the pressure
drop in the fluid flow can be measured by totaling the pressure drop in each of the system's
components.
CFD ANALYSIS OF ENGINE COOLING WATER PUMP
Define Goals
From theoretical and practical approach, pump design parameter are obtained which affects
the pump flow characteristic. To study pump flow characteristic, Ansys CFX is used which
will provide results with graphical representation of flow characteristic like pressure,
velocity, mass flow rate etc. at different location of pump.
Flow Geometry and Mesh Creation
The pump model geometry is complex and asymmetric due to the blade and volute shape.
The 3D CAD software was usedto extractpump fluid profile geometry from pump modelThe
pump model specification is given bellow in table 3. An Optimized mesh is used for analysis.
The model is divided into twodomains i.e. rotating and stationary.

Mesh - Stationary and
Identify Domain and Boundary Condition
In steady state type analysis,
& Stationary. The rotating domain includes the fluid profile which
impeller while the rest of the fluid region is defined as
defined for the fluid flow at impeller inlet, impeller outlet, Inlet and outlet of pump with
General connection and conservat
mixture of Ethylene Glycol & water is defined with required properties for the solver
equation in material library. The ma
investigated for cavitation effect in pump
Impeller Specification
Hub Dia 19.35 mm
Impeller Outside Dia 56 mm
Suction Dia Impeller OD
Flow Type Radial Flow
Blade Type Circular 2D
No of Blade 7 (CCW)
Total Height 23.47 mm
105
Pump Geometry 1
tationary and Rotating domain of pump flow
Boundary Condition
In steady state type analysis, Non Buoyant, two fluid domains are defined
rotating domain includes the fluid profile which is in contact with the
est of the fluid region is defined as Stationary domain. Interfaces are
General connection and conservative interface flux in fluid flow.Engine coolant, a 50/50 %
The mass transfer model is set to cavitation and the results are
effect in pump at different pump rpm.
19.35 mm
56 mm
Impeller OD
Radial Flow
Circular 2D
7 (CCW)
23.47 mm
two fluid domains are defined - Rotating
in contact with the
Stationary domain. Interfaces are
Engine coolant, a 50/50 %
and the results are

RESULT
Above results shows contour plots of velocity and pressure on different planes. Below graph
shows flow rate vs. head at different engine RPM. By carefully studying each case, it can be
concluded that at very low RPM, flow is turbulent. Also
cavitation is achieved at medium engine speed.
SIGNIFICANCE OF PUMP GEOMETRY
A common misconception about cooling systems is that if the coolant flows too
quickly through the system, it will not have time to cool properly.
cooling systems are a closed loop, coolant allowed to stay in the radiator longer will also
stay in the engine block longer producing increased coolant temperatures. This can
easily lead to ‘hot spots’ and ultimately, engine failure.
increases velocity by reducing pressure with providing sudden reduction in cross se
at outlet of pump. Sudden reduction also result into turbulent flow at the outlet which
contradictory helps in maintaining engine block temperatures which we can
above results also.
However turbulent flow at inlet leads to less pump
below vapor pressure of coolant then it leads to pump cavitation. From above results we can
conclude that venturi effect at the inlet of the pump helps in avoiding cavitation by increasing
inlet fluid pressure above vapor pressure at normal speed
106
0
2
4
6
8
0 20 40
HEAD(ft)
FLOW RATE (GPM)
3000 RPM 2625 RPM
concluded that at very low RPM, flow is turbulent. Also best pump efficiency with less
cavitation is achieved at medium engine speed.
GEOMETRY
quickly through the system, it will not have time to cool properly. Because automotive
easily lead to ‘hot spots’ and ultimately, engine failure. To avoidthesecentrifugal pump
velocity by reducing pressure with providing sudden reduction in cross se
contradictory helps in maintaining engine block temperatures which we can
However turbulent flow at inlet leads to less pump efficiency and also if pressure falls
low vapor pressure of coolant then it leads to pump cavitation. From above results we can
effect at the inlet of the pump helps in avoiding cavitation by increasing
apor pressure at normal speed and decreasing velocity of fluid.
60
FLOW RATE (GPM)
2250 RPM
best pump efficiency with less
Because automotive
centrifugal pump
velocity by reducing pressure with providing sudden reduction in cross section area
contradictory helps in maintaining engine block temperatures which we can see through
efficiency and also if pressure falls
low vapor pressure of coolant then it leads to pump cavitation. From above results we can
effect at the inlet of the pump helps in avoiding cavitation by increasing
and decreasing velocity of fluid.

107
CONCLUSION
The summary of the present research paper as follows
1. By studying different design points carefully it can be concluded that the existing
pump of Alto car is designed for best performance at normal car speed. Pump
geometry at inlet (venturi effect) avoids cavitation phenomenon and increase pump
efficiency significantly.
2. However at low and high speed of car, pump is subject to more cavitation. So there is
scope to improve that.
3. Sudden reduction at pump outlet is observed in existing pump, which is generally to
be avoided while designing the pump. But it helps in avoiding hot zones by increasing
velocity and making flow turbulent.
REFERENCES
[1] Rodrigo Lima Kagami, Edson LuizZaparoli, Cláudia Regina de Andrad, “ Cfd Analysis
of An Automotive Centrifugal Pump”, 14th Brazilian Congress of Thermal Sciences
and Engineering, October18-22, 2012
[2] Munish Gupta, Satish Kumar, Ayush Kumar, “Numerical Study of Pressure and
Velocity Distribution Analysis of Centrifugal Pump”, International Journal of Thermal
Technologies, ISSN 2277 – 4114,Vol.1, No.1 (Dec. 2011) ,pp-118-121.
[3] R.Ragoth Singh, M.Nataraj “Parametric Study and Optimization of Centrifugal Pump
Impeller by Varying The Design Parameter Using Computational Fluid Dynamics: Part
I”, Journal of Mechanical and Production Engineering (JMPE) ISSN 2278-3512 Vol.2,
Issue 2, Sep 2012 ,pp-87-97
[4] E.C. Bacharoudis, A.E. Filios, M.D. Mentzos1 and D.P. Margaris,“Parametric Study of
a Centrifugal Pump Impeller by Varying the Outlet Blade Angle”, The Open
Mechanical Engineering Journal, 2008, 2, pp-75-83
[5] Mohammed Khudhair Abbas “Cavitation In Centrifugal Pumps”, Diyala Journal of
Engineering Sciences, ISSN 1999-8716, 22-23 December. 2010, pp. 170-180
[6] AbdulkadirAman, SileshiKore and Edessa Dribssa ,“Flow Simulation and Performance
Prediction of Centrifugal Pumps Using CFD-Tool”, Journal of EEA, Vol. 28, 2011,
pp-59-65.
[7] Weidong Zhou, Zhimei Zhao, T. S. Lee, and S. H.Winoto ,“Investigation of Flow
Through Centrifugal Pump Impellers Using Computational Fluid Dynamics”,
International Journal of Rotating Machinery, 9(1): 49–61, 2003,pp-49-61.
[8] S.Rajendran and Dr.K.Purushothaman,“Analysis of a Centrifugal Pump Impeller Using
ANSYS-CFX”, International Journal of Engineering Research & Technology (IJERT)
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[9] http://www.engineeringtoolbox.com/specific-speed-pump-fan-d_637.html
[10] Manish Dadhich, Dharmendra Hariyani and Tarun Singh, “Flow Simulation (Cfd) &
Fatigue Analysis (Fea) of a Centrifugal Pump”, International Journal of Mechanical
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0976 – 6340, ISSN Online: 0976 – 6359.
[11] Kapil Chopra, Dinesh Jain, Tushar Chandana and Anil Sharma, “Evaluation of Existing
Cooling Systems for Reducing Cooling Power Consumption”, International Journal of
Mechanical Engineering & Technology (IJMET), Volume 3, Issue 2, 2012,
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