 The chief use of nozzle is to produce a jet of steam (or gas) of high velocity to produce thrust for the propulsion of rocket motors and jet engines and to drive steam or gas turbines.  A DIFFUSER is a device that increases the pressure of a fluid by slowing it down. This hot air passes through a high speed nozzle, a propelling nozzle, which enormously increases its kinetic energy. Increasing exhaust velocity increases thrust for a given mass flow, but matching the exhaust velocity to the air speed provides the best energy efficiency.‎Types · ‎Jet · ‎High velocity · ‎Propelling. A steam nozzle is a duct or passage of smoothly varying cross sectional area .. is slightly greater than the theoretical discharge even though we consider the.


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40. Flow of gases and steam through nozzles

It means the outlet velocity should be in axial direction of the nozzle. This condition must also satisfy the streamlines at the wall of the nozzle: The cone nozzle has lower a mass flow coefficient than ideal contour nozzle see Formula These types of contours be can use for non-circular steam nozzle theory and blade passages.


State at exit of converging nozzle The free flow at the exit of the nozzle can have two states 3, 4: The outlet gas stream is deformed and gradually mixes with the surrounding steam nozzle theory.

The gas stream area be must increased according Hugoniot condition.


The divergent gas stream forms oblique shock waves on border between the stream and the surroundings gas. These shock waves are reflected to the core of gas stream and they are decreased an efficiency of expansion they cause pressure drop.

The expansion is ended when the pressure is equal the surroundings pressure and a steam nozzle theory process is similar the previous case gradually mixes with the surrounding gas.

Nozzle - Wikipedia

The oblique lines inside flow are oblique shock waves, which arise at the exit edge of the nozzle and are reflecting from the boundary of the stream. Frequent contours of de Laval nozzles Ideal contour steam nozzle theory the diverging section of de Laval nozzle is designed by the method of characteristics 5.

There are analytical methods of design of contour diverging nozzle, where the contour of the nozzle is approximated by a polynomial first-order, second-order and the like 6, 7.

The contour of the nozzle on interval t-e is calculated by the method of characteristics through construction expansion waves inside the nozzle. The length of the ideal contour of the nozzle is steam nozzle theory than the nozzle with linear contour, therefore has lower internal efficiency due to internal friction of the working gas.

NPTEL :: Mechanical Engineering - Fluid Machinery

Ideal contour of de Laval nozzle is used in supersonic wind tunels, where is requirement significant uniform velocity field at the outlet: The ideal contour of nozzle is designed for maximum momentum of flow in axis direction.

The expansion waves are shown on figure also. The de Laval nozzles with cone steam nozzle theory are used as a supersonic blade row of one stage turbine for cases where other losses of stage are very high and therefore production of complicated contour of nozzle does not economic.

  • Flow of gases and steam through nozzles

This simple contour is also used for small steam nozzle theory engines, for small nozzles, for nozzle of injectors and ejectors etc.

These two parameters are sufficient to a calculation of the length of the diverging section of de Laval nozzle: The field velocity at the exit is not uniform. This contour is steam nozzle theory by an equation Rao according Rao, G.

The Bell nozzle is shorter than the linear nozzle but has higher internal efficiency and the axial momentum of flow: The Allman-Hoffman equation is steam nozzle theory for quicker optimization calculations at wide combinations of the states at the exit.