De Laval nozzle

Convergent/Divergent Nozzles (De Laval Nozzles) During frictionless adiabatic one-dimensional flow with changing cross-sectional area A the following relations are obeyed ... 

The high temperature gas generated in the combustion chamber of a rocket engine is expanded through a De Laval nozzle to convert a major portion of the enthalpy to mechanical thrust. The thrust F of a rocket engine is defined by the following conservation of momentum equation ... 

Near-equilibrium flow conditions generally yield the maximum thrust for rocket propulsion, because partial recombination of the dissociated atoms, as the temperature falls, releases additional kinetic energy. On the other hand, when the rocket engine is considered for high temperature chemical processing, it is invariably desirable to freeze the composition attained in the combustion chamber. From both theoretical and practical standpoints, it is not always possible to predetermine the flow conditions in the De Laval nozzle as the foregoing discussion indicates,... 

Figure 8.3 is a plot of AM versus Ji for steady, one-dimensional, frictionless, adiabatic flow of a perfect gas. It is, in effect, a design guide for a supersonic nozzle If we wish the Mach number to increase linearly with distance in steady, isentropic flow of a perfect gas, then the cross-sectional area-distance relation must be exactly the curve in Fig. 8.3, This is the diagram for a converging-diverging nozzle, a type of nozzle commonly referred to as a de Laval nozzle after its inventor, who used it in the first practical steam turbine [11]-...

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