How does a converging diverging nozzle work?
This nozzle configuration is called a convergent-divergent, or CD, nozzle. In a CD nozzle, the hot exhaust leaves the combustion chamber and converges down to the minimum area, or throat, of the nozzle. The throat size is chosen to choke the flow and set the mass flow rate through the system.
Where are converging diverging nozzles used?
Convergent-divergent type of nozzles are mostly used for supersonic flows because it is impossible to create supersonic flows (mach number more than one) in convergent type of nozzle and therefore it restricts us to a limited amount of mass flow through a particular nozzle.
Why are converging diverging nozzles used in rockets to generate high thrust?
Beyond that to further increase the speed, the nozzle needs to diverge. So the complete system works like this – First you converge the nozzle to increase its speed to Mach 1. Then diverge to increase the speed further.
What is the difference between convergent nozzle and divergent nozzle?
Nozzles can be described as convergent (narrowing down from a wide diameter to a smaller diameter in the direction of the flow) or divergent (expanding from a smaller diameter to a larger one).
What is the function of divergent nozzle?
Convergent – Divergent nozzles are used to increase the flow of gas to supersonic speeds (as in the case of rockets). Their cross-sectional area first decreases and then increases. The area where the diameter is minimum is called the throat.
What is the functions of divergent nozzle?
Why convergent-divergent nozzle is used in steam turbine?
convergent – divergent nozzle is widely used in steam turbines. The nozzle converges first to the smallest section and then diverges up to exit. The smallest section of the nozzle is called throat. The divergent portion of nozzle allows higher expansion ratio i.e., increases pressure drop.
What is converging nozzle?
The most basic type of nozzle, the converging nozzle, is essentially a tube with an area that gradually decreases from the entry to the exit, or throat. As the nozzle area decreases, the flow velocity increases, with the maximum velocity occurring at the throat.
What is critical pressure in convergent-divergent nozzle flow?
Choked flow is a limiting condition where the mass flow will not increase with a further decrease in the downstream pressure environment while upstream pressure is fixed. For chocked flow in convergent – divergent nozzle, Mach number at throat is equal to 1 and the pressure at throat is equal to the critical pressure.
What is a convergent nozzle?
A convergent nozzle is a nozzle that starts big and gets smaller-a decrease in cross-sectional area. As a fluid enters the smaller cross-section, it has to speed up due to the conservation of mass. To maintain a constant amount of fluid moving through the restricted portion of the nozzle, the fluid must move faster.
What is diverging nozzle?
A de Laval nozzle (or convergent-divergent nozzle, CD nozzle or con-di nozzle) is a tube which is pinched in the middle, making a carefully balanced, asymmetric hourglass shape.
What happens to the sound speed as the flow goes through the converging diverging nozzle with supersonic flow at the exit?
When the nozzle isn’t choked, the flow through it is entirely subsonic and, if you lower the back pressure a little, the flow goes faster and the flow rate increases. As you lower the back pressure further the flow speed at the throat eventually reaches the speed of sound (Mach 1).
What is the purpose of a convergent nozzle?
What is converging and diverging duct?
A duct that has a decreasing cross section in the direction of fluid flow is convergent, until a minimum area is reached. Thereafter, the cross section increases, or becomes divergent.
What happens to velocity in the diverging nozzle?
Apparently there’s a type of nozzle that is often used in rocket and jet engines, called a converging-diverging nozzle, that accelerates air by first converging so the air speeds up to the speed of sound, then diverging, accelerating it to supersonic speeds.