gdjp1

ME 2351 GAS DYNAMICS & JET PROPULSIONObjectives: To understand the basic difference incompressible and compressible flow between

To gain knowledge about flow through variable area ducts (namely nozzles and diffusers ) and constant area ducts To study the phenomenon of shock waves and its effect on flow To gain basic knowledge about jet and rocket propulsion

Dr. S. Arivazhagan, Professor of Mech Engg , St Joseph's College of Engg

ME 2351 GAS DYNAMICS & JET PROPULSIONSyllabus


ME 2351 GAS DYNAMICS & JET PROPULSIONSyllabus


ME 2351 GAS DYNAMICS & JET PROPULSION


ME 2351 GAS DYNAMICS & JET PROPULSIONUnit I Compressible Flow Fundamentals Gas Dynamics: What is Gas Dynamics? Fluid dynamics of compressible flows Deals with dynamics and thermodynamics of compressible flows Takes into account compressibility (which Fluid Mechanics does not consider) Applications: Steam and Gas Turbines High Speed Turbocompressors High Speed Aerodynamics Rocket and Missile Propusion Properties considered:

Temperature, Pressure, Density, Internal Energy, Enthalpy, Entropy and viscosity


ME 2351 GAS DYNAMICS & JET PROPULSIONUnit I Compressible Flow Fundamentals What must be known? (Prerequisites): Laws: First Law of Thermodynamics (Energy Equation) Second Law of Thermodynamics (Entropy Relations) Law of Conservation of Mass (Continuity Equation) Newtons Second Law of Motion(Momentum Equation) Terms: Fluid System Control Volume State Process CycleDr. S. Arivazhagan, Professor of Mech Engg , St Joseph's College of Engg

ME 2351 GAS DYNAMICS & JET PROPULSIONUnit I Compressible Flow Fundamentals What must be known? (Prerequisites): Terms: Property Continuum Pure Substance Pressure Density Equillibrium Temperature Energy Work Heat Zeroth Law of Thermodynamics First Law of Thermodynamics Specific Heats Ideal and Real Gases and the equations applicable Dr. S. Arivazhagan, Professor of Mech Engg ,St Joseph's College of Engg

ME 2351 GAS DYNAMICS & JET PROPULSIONUnit I Compressible Flow Fundamentals What must be known? (Prerequisites): Terms: Second Law of Thermodynamics Reversible Flow, Irreversible Flow Adiabatic Process Change of Entropy Third Law of Thermodynamics Isentropic Process Bulk Modulus of Elasticity Coefficient of Compressibility Streamline Stream Tube Incompressible Flow Compressible Flow Steady FlowDr. S. Arivazhagan, Professor of Mech Engg , St Joseph's College of Engg

ME 2351 GAS DYNAMICS & JET PROPULSIONUnit I Compressible Flow Fundamentals What must be known? (Prerequisites): Terms: Unsteady Flow Flow and Non- Flow Processes Viscosity Reynolds Number Laminar and Turbulent Flow Coefficient of Skin Friction Mach Number Properties of Atmosphere:


ME 2351 GAS DYNAMICS & JET PROPULSIONUnit I Compressible Flow Fundamentals Energy Equation:The Energy Equation for the CV is:

1 2 h1 C1 gZ1 q ! 2h2

WS Q Z21 2

1 2

2 2

g

2

wS

Generally g(Z2-Z1) is negligible;

Z1

h1

2 1

q!

1 2 h2 C 2 2

S

Datum Z = 0Adiabatic Energy Equation for the CV is:

1 2 h1 C1 ! 2

1 2 h2 C2 2

S


ME 2351 GAS DYNAMICS & JET PROPULSIONUnit I Compressible Flow Fundamentals Energy Equation: Work in flow process when the changes in KE is negligible,2

wS ! h1 h2 ! dh1 2

wS ! c p dT1

wS ! c p (T1 T2 )Work in a reversible flow process, ws:

wS ! vdpDr. S. Arivazhagan, Professor of Mech Engg , St Joseph's College of Engg

ME 2351 GAS DYNAMICS & JET PROPULSIONUnit I Compressible Flow Fundamentals Energy Equation: Equation for Adiabatic Energy Transformation 1 2 h1 C1 ! 21 2 h2 C2 2decelerated to zero velocity at Z=0)

Stagnation Enthalpy h0( of a gas is its enthalpy when it is adiabatically

Flow

p0 T0 C=0 h0p,T, C

Large settling chamber

Using Adiabatic Energy Transformation Eqn,

1 h0 ! h C 2 2


ME 2351 GAS DYNAMICS & JET PROPULSIONUnit I Compressible Flow Fundamentals Energy Equation: Stagnation Temperature T0( of a gas is its temperature when it is adiabatically decelerated to zero velocity at Z=0):From Stagnation enthalpy equation,

1 c pT0 ! c pT C 2 2

C2 T0 ! T 2c pT0 C2 ! 1 2c pT T T0 C2 ! 1 2 KRT (K 1) T

Velocity temperature Tc


ME 2351 GAS DYNAMICS & JET PROPULSIONUnit I Compressible Flow Fundamentals Energy Equation: Stagnation Temperature T0:

c2 But, KRT ! a ; !M2 a22

Therefore,T0 K 1 2 ! 1 M T 2

Stagnation Velocity of Sound:

a0 ! KRT0Substituting,R! K 1 cp K

a0 ! (K 1)c pT0 a0 ! (K 1) h0Dr. S. Arivazhagan, Professor of Mech Engg , St Joseph's College of Engg

ME 2351 GAS DYNAMICS & JET PROPULSIONUnit I Compressible Flow Fundamentals Energy Equation: Stagnation Pressure (the pressure of a fluid which is attained when it is decelerated to zero velocity at zero elevation):p0 T0 ! p T K K 1

K 1 2 ! 1 M 2

K K 1

Stagnation density:V p0 ! V0 p T ! 0 T 1K

1 K 1

K 1 2 ! 1 M 2

1 K 1


ME 2351 GAS DYNAMICS & JET PROPULSIONUnit I Compressible Flow Fundamentals Energy Equation: Stagnation State(the state of a fluid attained by decelerating to zero velocity at zero elevation):

T T0 0

p0

p0

T sDr. S. Arivazhagan, Professor of Mech Engg , St Joseph's College of Engg

ME 2351 GAS DYNAMICS & JET PROPULSIONUnit I Compressible Flow Fundamentals





























































































































































































gdjp1

Documents

professor of mech engg

st josephs college of

unsteady flow flow

reversible flow process

adiabatic energy equation

c pt c

stagnation enthalpy

internal energy