The effects of Mach number and Nozzle pressure ratios (NPR) on Mass flow rate, Maximum pressure, and Maximum velocity and on Maximum force are studied using Fluent Analysis. The classical one dimensional inviscid theory does not reveal the complex flow features in a convergent divergent nozzle accurately. The code fluent has been used to compute flow using a coupled and axisymmetric Convergent Divergent nozzle for different nozzle ratios and for different Mach numbers.
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Flow Analysis in a Convergent-Divergent Nozzle Using CFD
1Gutti Rajeswara Rao,
2U.S. Ramakanth,
3A. Lakshman
1Assistant Professor, St. Marry Engineering College, India 2Associate Professor, VITAM Engineering College, India
3M.Tech CAD/CAM SMBS, VIT University, India
ABSTRACT
The effects of Mach number and Nozzle pressure ratios (NPR) on Mass flow rate, Maximum pressure,
and Maximum velocity and on Maximum force are studied using Fluent Analysis. The classical one
dimensional inviscid theory does not reveal the complex flow features in a convergent divergent
nozzle accurately. The code fluent has been used to compute flow using a coupled and axisymmetric
Convergent Divergent nozzle for different nozzle ratios and for different Mach numbers.
Keywords: Nozzle Pressure Ratio (NPR), Mach number, Convergent-Divergent Nozzle, CFD.
1. INTRODUCTION
In the present days there is a huge development in Aerospace Engineering for defense and civil
prospects. Extensive research is being carried out in these fields. This project tries to establish the
methods of developing the rocket nozzle of a solid propellant rocket. The test is virtualized at
different Mach numbers, where the flow conditions are derived.
The virtualization is one of the major developments in the field of research, which revolutionized
Aerospace engineering, along with all other branches. The computational techniques are used widely
for getting better results, close to experimental techniques.
The flow through a converging-diverging nozzle is one of the benchmark problems used for modeling
the compressible flow through computational fluid dynamics. Occurrence of shock in the flow field
displays one of the most prominent effects of compressibility over fluid flow. Accurate shock
predication is a challenge to the CFD fraternity. In order to resolve the high pressure gradients we
need to use some special numerical schemes along with fine grid. In some cases, local grid adaption
can be helpful. The one-dimensional inviscid isentropic flow in a convergent-divergent nozzle is a
classical text book problem ,which has different flow regimes depending upon the nozzle pressure
ratio(NPR).The inviscid theory predicts a simple shock structure consisting of a normal shock
followed by a smooth recovery to exit pressure in the divergence part of a chocked nozzle for the
nozzle pressure ratios corresponding to the over-expanded flow regimes. But ,in reality, multi
dimensionality and viscous effects like wall boundary layer and flow separation drastically alter the
flow in a CD nozzle. The over-expanded flow regime in CD nozzles of different shapes and sizes has
been a subject matter of numerous investigations because of their wide range of applications. One of
the more recent investigations in an experimental study of flow in rectangular over expanded
supersonic nozzles exploring the complexity nature of such flows. The prediction of such flows also
presents a great challenge to any CFD code.
2. LITERATURE
CONVERGENT-DIVERGENT nozzle is designed for attaining speeds that are greater than speed of sound.
the design of this nozzle came from the area-velocity relation (dA/dV)=-(A/V)(1-M^2) M is the Mach
number ( which means ratio of local speed of flow to the local speed of sound) A is area and V is velocity.
International Journal of Research in Mechanical Engineering