Question

Explain the importance of Fanno and Rayleigh flows in the design of Nozzles for jet propulsion

Answer 1

Fanno Flows:-Fanno flow refers to adiabatic flow through a constant area duct where the effect of friction is considered.

Importance of Fanno Flow:-

1-Fanno flow model certainly applies to incompressible flow because in this  For this model, the duct area remains constant, the flow is assumed to be steady and one-dimensional, and no mass is added within the duct.

2-The Fanno flow model is often used in the design and analysis of nozzles.

3- In a nozzle, the converging or diverging area is modeled with isentropic flow, while the constant area section afterwards is modeled with Fanno flow.

4-The Fanno flow model is also used extensively with the Rayleigh flow model.

Rayleigh Flow:-Rayleigh flow refers to frictionless, non-Adiabatic flow through a constant area duct where the effect of heat addition or rejection is considered.

Importance of Rayleigh Flows:-

1-The Rayleigh flow model certainly also applies to incompressible flow because  this model, the duct area remains constant and no mass is added within the duct.

2-The Rayleigh flow model begins with a differential equation that relates the change in Mach number with the change in stagnation temperature, T₀.

3-These values are significant in the design of combustion systems.

4-The Rayleigh flow model has many analytical uses, most notably involving aircraft engines.

5-The Rayleigh flow model is also used extensively with the Fanno flow model.