The well-known Fanno-line process deals with a perfect gas flowing in a duct of constant cross-sectional area with friction in which there is no heat transfer to or. Show that the maximum (static) temperature in Rayleigh flow occurs when the a T –s diagram for the system, showing the complete Fanno and Rayleigh lines. It is possible to obtain physical picture of the flow through a normal shock by employing some of the ideas of Fanno line and Rayleigh line Flows. Flow through a.

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The Fanno flow model is often used in the design and analysis of nozzles. This indicates that cooling, instead of heating, causes the Mach number to move from 0. Views Read Edit View history. The Rayleigh flow model has many analytical uses, most notably involving aircraft engines. First Law of Thermodynamics-The Energy Equation 4 Work transfer can also occur at the control surface when a force associated with fluid normal stress.

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Shock waves and expansion waves Rayleigh flow Fanno flow Assignment – ppt video online download

A given flow with a constant duct area can switch between the Rayleigh and Fanno models at these points. Brodkey pub These equations are shown below for Fanno and Rayleigh flow, respectively.

Disregarding frictional losses, determine the velocity, static temperature and static pressure at the duct inlet. The average friction factor for the duct is estimated to be if the Ma number at the duct exit is 0. The Fanno line curve does rayleigg satisfy Eq.

Chap 5 Quasi-One- Dimensional Flow. Oblique shocks occur when a gas flowing at supersonic speeds strikes a flat or inclined surface. By using this site, you agree to the Terms of Use and Privacy Policy. At the same time, for a given state” 1″, the end state “2” of the normal shock must lie on both the Fanno line and Rayleigh line passing through state “1. Heat addition will cause both supersonic and subsonic Mach numbers to approach Mach 1, resulting in choked flow.

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Retrieved from ” https: On the other hand, for a fanbo with an upstream Mach number less than 1.

However, the entropy values for each model are not equal at the sonic state. An Engineering Approach, 5th edition by Yunus A. We think you have liked this presentation. OK Flow of Compressible Fluids. Fanno flow is the adiabatic flow through a constant area duct where the effect of friction is considered. Conversely, adding heat to a duct with an upstream, supersonic Mach lknes will cause the Mach number to decrease until the flow chokes.

Normal shock waves are perpendicular to flow whereas inclined shock waves, as the name implies, are typically inclined relative to the flow direction. The Rayleigh flow model is also used extensively with the Fanno flow model.

Producing a shock wave inside the combustion chamber of an engine due to thermal choking is very eayleigh due to the decrease in mass flow rate and thrust. In other projects Wikimedia Commons. The characteristic aspect of Rayleigh flow is its involvement of heat transfer.

The ratios for the pressure, density, static temperature, velocity and stagnation pressure are shown below, respectively. Here we confine the analysis. The Fanno line represents the states that satisfy the conservation of mass and energy equations. The ratios for the pressure, density, temperature, velocity and stagnation pressure are shown below, respectively.

In order to draw a Fanno line curve through state “1”, we require a locus of mathematical states that satisfy Eqs Fluid mechanics Fluid dynamics Aerodynamics. The Fanno line defines the possible states for a gas when the mass flow rate and total enthalpy are held constant, but the momentum varies. The frictional effect is modeled as a shear stress at the wall acting on the fluid with uniform properties over any cross section of the duct.

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The area and mass flow rate are held constant for Rayleigh flow. However, the entropy values for each model are not equal at the sonic state. By using this site, you agree to the Terms of Use and Privacy Policy. Wall friction is significant and should be considered when studying flow through long flow sections, e.

What are the main assumptions associated with Rayleigh flow?

Fanno flow

This means that a subsonic flow entering a duct with friction will have an increase in its Mach number until the flow is choked. These two models intersect linex points on the enthalpy-entropy and Mach number-entropy diagrams, which is meaningful for many applications. My presentations Profile Feedback Log out. The intersection points occur at the given initial Mach number and its post- normal shock value. This page was last edited on 23 Julyat Since all the condition of state “1” are known, there is no difficulty in locating state “1” on T-s diagram.

The Rayleigh line does not satisfy Eq. A given flow with a constant duct area can switch between the Fanno and Rayleigh models at these points. While Rayleigh line curve through state “1” gives a locus of mathematical states that satisfy Eqs From Wikipedia, the free encyclopedia.

What are the main assumptions associated with Fanno flow? Assuming the Fanning friction factor is a constant along the duct wall, the differential equation can be solved easily. A stagnation property contains a ‘0’ subscript. The main assumptions associated with Fanno flow are: