An Overview of Aircraft Propelling Nozzles

Various nozzle designs act differently and each is used in its own unique application. To accommodate different engines, the internal structure of nozzles can be either convergent, divergent, or convergent-divergent (C-D) in shape. Operating off of the Venturi effect, propelling nozzles are designed to bring exhaust gasses to ambient pressure and form them into a jet. Venturi effect refers to the fall in fluid pressure caused by fluid moving through a restricted segment of a pipe. When the pressure is high enough, the flow will choke and the jet will become supersonic. The temperature and pressure of the gas provide the energy required to accelerate the stream. The gas expands adiabatically (without losing heat or mass) and hence efficiently. The gas then accelerates to a final exit velocity that is determined by the pressure and temperature at nozzle entry, the ambient pressure it exits, and the expansion efficiency.
 
During the combustion process within jet engines, exhaust gasses are produced by burning a mixture of air and jet fuel. As gasses are produced, they must then travel through the narrow passage of an engine's propelling nozzle, its shape aiding in providing enough force to drive the plane forward. Additionally, nozzles also play an active role in generating reverse thrust which occurs after the aircraft has landed to assist in rapid deceleration. This is done by reversing the flow of exhaust in the opposite direction required for propulsion.
 
Types of Propelling Nozzles
 
There are different types of propelling nozzles, those of which include fixed-area moving nozzles, low area ratio propelling nozzles, and ejector propelling nozzles. However, alternate nozzles also exist to suit various engine applications and their particular demands, including: afterburner nozzles, variable area nozzles, variable geometry nozzles, rocket nozzles, and others. In addition they are also characterized by different sizes and shapes. Although different propelling nozzles may vary in how they work, they are all still generally designed to pressurize the combustion gasses produced by jet engines.
 
The shape and design of a passageway making up a nozzle is critical because their propulsion output is dependent on such features. Anything other than smooth airflow will reduce engine efficiency and increase the risk of component failure due to excess vibrations induced by eddies or turbulence.
 
Conclusion

When maintenance requires the repair or overhaul of aircraft parts and components, Aerospace Purchasing is here to serve as your one-stop-shop for all your aerospace product needs. For propelling nozzles and other aviation items, we at Aerospace Purchasing can help you find exactly what you need through the submission of an Instant RFQ form. Upon submission of a completed RFQ form, a dedicated account representative will respond back to you in 15 minutes or less with a competitive quote for your comparisons, and we are always available to help customers via phone or email, 24/7x365.