INTERNATIONAL JOURNAL OF PROFESSIONAL ENGINEERING STUDIES
Volume VI /Issue 4 / JULY 2016
COMPARATIVE DESIGN AND ANALYSIS OF TRINOZZLE WITH CONVERGENT-DIVERGENT NOZZLE 1
K NAGARJUNA REDDY, 2N SRINIVASA RAJNEESH DEPARTMENT OF MECHANICAL ENGINEERING MALLA REDDY ENGINEERING COLLEGE (AUTONOMOUS)
(An Autonomous Institution approved by UGC and affiliated to JNTUH, Approved by AICTE, Accredited by NAAC with ‘A’ Grade and NBA & Recipient of World Bank Assistance under TEQIP Phase- II S.C.1.1) Maisammaguda, Dhulapally (Post. Via.Kompally), Secunderabad – 500 100.
_____________________________________________________________________________ Abstract:
study is carried out by using SOLID
Nozzle is a device designed to
WORKS
PREMIUM
2014.The
nozzle
control the rate of flow, speed, direction,
geometry modeling and mesh generation has
mass, shape, and/or the pressure of the Fluid
been done using SOLID WORKS CFD
that
Convergent-
Software. Computational results are in good
divergent nozzle is the most commonly used
acceptance with the experimental results
nozzle since in using it the propellant can be
taken from the literature.
heated
Introduction To Nozzle
exhaust
from
them.
incombustion chamber.
In this
project we designed a new Tri-nozzle to increase the velocity of fluids flowing
Swedish engineer of French descent
through it. It is designed based on basic
who, in trying to develop a more efficient
convergent-Divergent nozzle to have same
steam engine, designed a turbine that was
throat area, length, convergent angle and
turned by jets of steam. The critical
divergent angle as single nozzle. But the
component – the one in which heat energy
design of Tri-nozzle is optimized to have
of the hot high-pressure steam from the
high expansion co-efficient than single
boiler was converted into kinetic energy –
nozzle without altering the divergent angle.
was the nozzle from which the jet blew onto
In the present paper, flow through theTri-
the wheel. De Laval found that the most
nozzle and convergent divergent nozzle
efficient conversion occurred when the
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INTERNATIONAL JOURNAL OF PROFESSIONAL ENGINEERING STUDIES
Volume VI /Issue 4 / JULY 2016
nozzle first narrowed, increasing the speed
nozzle came from the area-velocity relation
of the jet to the speed of sound, and then
(dA/dV) =-(A/V) (1-M^2) M is the Mach
expanded again.[1][5]Above the speed of
number (which means ratio of local speed of
sound (but not below it) this expansion
flow to the local speed of sound) A is area
caused a further increase in the speed of the
and V is velocity the following information
jet and led to a very efficient conversion of
can be derived from the area-velocity
heat energy to motion.The theory of air
relation.[5]
resistance[1] was first proposed by Sir Isaac Newton in 1726. According to him, an aerodynamic force depends on the density and velocity of the fluid, and the shape and the size of the displacing object. Newton’s theory
was
theoretical
soon solution
followed of
by
fluid
other motion
1. For incompressible flow limit, AV = constant. This is the famous volume conservation equation or continuity equation for incompressible flow.[5] 2. For M < 1, a decrease in area results in increase
of
velocity
and
vice
versa.
problems. All these were restricted to flow
Therefore, the velocity increases in a
under idealized conditions, i.e. air was
convergent
assumed to possess constant density and to
Divergent duct. [5]
move in response to pressure and inertia.
duct
and
decreases
in
a
3. For M > 1, an increase in area results in
A nozzle is a device designed to
increases of velocity and vice versa, i.e. the
control the direction or characteristics of a
velocity increases in a divergent duct and
fluid flow (especially to increase velocity) as
decreases in a convergent duct. This is
it exits (or enters) an enclosed chamber. A
directly opposite to the behavior of subsonic
nozzle is often a pipe or tube of varying
flow in divergent and convergent ducts.[5]
cross sectional area.
4. For M = 1, dA/A = 0, which implies that the location where the Mach number is
Literature Review Convergent-Divergent
nozzle
is
designed for attaining speeds that are greater than speed of sound. The design of this IJPRES
unity, the area of the passage is either minimum or maximum. We can easily show that the minimum in area is the only physically realistic solution. 61
INTERNATIONAL JOURNAL OF PROFESSIONAL ENGINEERING STUDIES
Volume VI /Issue 4 / JULY 2016
Functions Of Nozzle
while meetinglife and reliability goals.
The purpose of the exhaust nozzle is to increase the velocity of the exhaust gas
Introduction To Convergent And
before discharge from the nozzle and to
Divergent Nozzle
collect and straighten the gas flow. For large values of thrust, the kinetic energy of the exhaust gas must be high, which implies a high exhaust velocity. The pressure ratio across the nozzle controls the expansion process and the maximum uninstalled thrust for a given engine is obtained when the exit pressure (Pe) equals the ambient pressure (P0).The functions of the nozzle may be summarized by the following list:[2]
with
minimum
total
exit
and
atmospheric
3. Mix core and bypass streams of
nozzle) is a tube that is pinched in the middle,
making
a
carefully
balanced,
accelerate a hot, pressurized gas passing through it to a higher speed in the axial
thrust
energy of the flow into kinetic energy.[3][5]
some
types
turbines and rocketengine
turbofan if necessary. for
nozzle or con-di
Because of this, the nozzle is widely used in
pressure as closely as desired.
4. Allow
nozzle, CD
(thrust) direction, by converting the heat
pressure loss. 2. Match
divergent
asymmetric hourglass shape. It is used to
1. Accelerate the flow to a high velocity
A de Laval nozzle (or convergent-
reversing
if
desired.
of steam nozzles.It
also
sees use in supersonic jet engines. Conditions for operation
5. Suppress jet noise, radar reflection, and
infrared
radiation (IR)
if
desired. 6. Do all of the above with minimal cost, weight, and boat tail drag
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INTERNATIONAL JOURNAL OF PROFESSIONAL ENGINEERING STUDIES
Its operation relies on the different
Volume VI /Issue 4 / JULY 2016
I.
properties of gases flowing at subsonic and
The friction between the nozzle surface and steam
supersonic speeds. The speed of a subsonic
II.
flow of gas will increase if the pipe carrying
III.
Internal friction of steam itself and The shock losses
it narrows because the mass flow rate is
Most of these frictional losses occur
constant.[3] The gas flow through a de Laval
between the throat and exit in convergent
nozzle is isentropic (gas entropy is nearly
divergent nozzle.
constant). In a subsonic flow the gas is compressible,
and sound will
propagate
through it. At the "throat", where the crosssectional area is at its minimum, the gas velocity locally becomes sonic (Mach number = 1.0), a condition called choked flow. As the nozzle cross-sectional area
Steam Enters nozzle with high pressure and very low velocity (velocity is generally neglected).Leaves nozzle with high velocity &low pressure. All this is due to the reason that heat energy at steam is converted into K.E as it passes through nozzle[5].
increases, the gas begins to expand, and the gas flow increases to supersonic velocities.[3] THEORETICAL BACK GROUND Flowthrough Nozzles: The steam flow through the nozzles may be assumed as adiabatic flow. Since
Modeling of Tri-Nozzle: First of all convergent section of TriNozzle was designed for our convenience to view and modify the cross-section of Throat. Leaving thickness of nozzle Loft cut is performed three times.
during the expansion of steam in nozzle neither heat is supplied or rejected work[5]. As steam passes through the nozzle it loses its pressure as well as heat. When the steam flows through a nozzle the final velocity of steam for a given pressure drop is reduced due to following reasons[5]
Similarly after construction of convergent section we work on divergent section.
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INTERNATIONAL JOURNAL OF PROFESSIONAL ENGINEERING STUDIES
It was designed to have three different entrances in throat and one in
Volume VI /Issue 4 / JULY 2016
Solidworks Flow Simulation Introduction:
entrance of Nozzle.
Solid Works Flow Simulation 2010 is a fluid flow analysis add-in package that is available forSolidWorks in order to obtain solutions to the full Navier-Stokes equations that govern the motion of fluids. Flow Simulation involves a number of basic steps that are shown in the following flowchart in figure.
Modeling of single nozzle: First select a new file and front plane Draw sketch as follows
With the help of revolve option in solidworks taking the axis line as reference revolve the sketch around axis forms the single nozzle.
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Flowchart for fluid flow analysis using Solidworks Flow simulation setting up aSolid works
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INTERNATIONAL JOURNAL OF PROFESSIONAL ENGINEERING STUDIES
Flow simulation of tri nozzle: Simulation of Tri-Nozzle is done
Volume VI /Issue 4 / JULY 2016
And exit conditions of nozzles are selected as vaccum.
step by step with the help of simulation wizard of Solid Works flow simulation software, those involves selection of inlet, outlet from Nozzle geometry and type of fluid flowing inside the nozzle also to be selected and boundaries has to be assigned.
Results: At given input conditions and 5 bar pressure the exit velocity of fluid from nozzle reached to 1040 m/s. images showing velocity distribution along the length of nozzle and respective graph are shown below
After selection of boundaries and fluids we have to assign the boundary conditions like inlet mass flow rate, pressure, and exit
Graph showing velocity curve
conditions. Here Inlet mass flow rate is taken as 50kg/s with 5 bar and 10 bar pressure separately
At given input conditions and 5 bar pressure the exit velocity of fluid from IJPRES
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INTERNATIONAL JOURNAL OF PROFESSIONAL ENGINEERING STUDIES
nozzle reached to 1200 m/s. images showing
Volume VI /Issue 4 / JULY 2016
Vacuum pressure outlet
velocity distribution along the length of nozzle and respective graph are shown below
Results: At given input conditions and 5 bar pressure the exit velocity of fluid from Graph showing velocity curve
nozzle reached to 661.6 m/s. images showing velocity distribution along the length of nozzle and respective graph are shown below
For single nozzle Simulation of Single Nozzle is done similarly as Tri-Nozzle. All the boundary
Graph showing velocity curve
conditions are also same given to TriNozzle. Here also Inlet mass flow rate is taken as 50kg/s with 5 bar and 10 bar pressure separately At given input conditions and 10 bar pressure the exit velocity of fluid from nozzle reached to 740 m/s. images showing velocity distribution along the length of IJPRES
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INTERNATIONAL JOURNAL OF PROFESSIONAL ENGINEERING STUDIES
Volume VI /Issue 4 / JULY 2016
nozzle and respective graph are shown
below
Analysis is done on single nozzle at 5 bars and 10 bars and values are noted.
Velocity of both nozzles at 5 bar and 10barpressure are tabulated in results table.
Thus variations in velocities at certain given pressures of convergent and divergent nozzle are analyzed in
Graph showing velocity curve
this project.
Pressure
Conclusion and Results:
Modeling
and
Single Nozzle
Tri-Nozzle
5 bar
661.6
1040
10 bar
740
1200
From our experiment we can say that Trianalysis
of
Convergent and divergent nozzle is
nozzle is giving more exit velocity of fluid than single nozzle at same input conditions and vacuum exit conditions.
done in Solid works 2016
Velocity(m/s)
Tri-nozzle is first modeled and
Both the nozzles are designed to have
analyzed in Solid works then an
same throat area, length, same convergent
individual single nozzle is designed
angle and divergent angles.
with same throat area and done analysis
at
5bars
and
10bars
respectively.
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References: [1] Pardhasaradhi
Natta,
V.Ranjith
Analysis is done on Tri-nozzle at
Kumar,
5bars and 10 bars and values are
Rao”Flow
noted.
Nozzle Using Computational Fluid
Dr.Y.V.Hanumantha Analysis
of
Rocket
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INTERNATIONAL JOURNAL OF PROFESSIONAL ENGINEERING STUDIES
Volume VI /Issue 4 / JULY 2016
Dynamics (Cfd)” Vol. 2, Issue 5,
Micro
September- October 2012
Corporation.
[2] Jack
D.
Mattingly,
CFD Research
T.
[8] Kazuhiro Nakahashi, “Navier-Stokes
Washington),
Computations of two and three
Willium H. Heiser, U.S. Air Force
dimensional cascade flow fields”,
Acadamy.
Vol.5, No.3, May-June 1989.
Pratt(University
[3] C.J.
Clarke
of
and
David
channels”
B.
Carswell
[9] Romine,
G.
L.,
“Nozzle
Flow
(2007). Principles of Astrophysical
separation,” AIAA Journal, Vol. 36,
Fluid Dynamics (1st ed.). Cambridge
No.9, Sep. 1998. Pp 1618- 1625.
University Press. p. 226 [4] A.A.Khan “Viscous
and
[10]
T.R.Shembharkar,
flow
analysis
in
a
Convergent-Divergent
nozzle”.
Proceedings of the
international
Dutton,
J.C.,
“Swirling
Supersonic Nozzle Flow,” Journal of Propulsion and Power, vol.3, July 1987, pp. 342-349. [11]
Elements of Propulsion: Gas
conferece on Aero Space Science
Turbines and Rockets ---- Jack D.
and Technology, Bangalore, India,
Mattingly
June 26-28, 2008. [5] Gutti
Rajeswara
[12] Rao,
U.S.
Ramakanth, A Lakshman “Flow
Introduction To Cfd---- H K
Versteeg &W Malalasekera [13]
Rocket
and
Spacecraft
analysis in a Convergent-Divergent
Propulsion Principles, Practice and
Nozzle using CFD“Volume-1,Issue-
New
2,October-December, 2013.
Springer, 2005) ---- Turner M.
Developments
(2nd
ed.,
[6] H.K.Versteeg and W.MalalaSekhara, “An introduction to Computational fluid Dynamics”, British Library cataloguing pub, 4th edition, 1996. [7] M.M.Atha vale and H.Q. Yang, “Coupled field thermal structural simulations in Micro Valves and
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INTERNATIONAL JOURNAL OF PROFESSIONAL ENGINEERING STUDIES
1. K NAGARJUNA REDDY
Volume VI /Issue 4 / JULY 2016
2. N SRINIVASA RAJNEESH
Studying M.Tech in stream of Thermal Engineering ENGINEERING
from
MALLAREDDY
COLLEGE.
Completed
B.Tech in Mechanical Engineering in 2013 from QIS COLLEGE OF ENGINEERING AND TECHNOLOGY, Ongole. E-mail id:
[email protected]
Completed B.Tech. in Mechanical engineering in 2001 from V.N.R.VJIET Engineering College,Hyderabad Affiliated to JNTUH, and M.Tech in Energy Technology in 2005 from Pondicherry Engineering college Affiliated to Pondicherry University, Pondicherry. Working as Associate Professor at MALLA REDDY ENGINEERING COLLEGE(AUTONOMOUS) , Dulapally Rd, Maisammaguda,Hyderabad, Telangana, India. Area of interest includes: Engine,Biofuel,Energy.
I.C
E-mail id:
[email protected]
IJPRES 69