What is the advantage of convergent-divergent nozzle?
In convergent-divergent type of nozzles we can increase the flow velocity much higher than sonic velocity that is why these type of nozzles have a wide applications such as propelling nozzles in jet engines or in air intake for engines working at high rpms.
What is the purpose of a converging diverging nozzle?
A converging diverging nozzle is generally intended to produce supersonic flow near the exit plane. If the back pressure is set at (vi), the flow will be isentropic throughout the nozzle, and supersonic at nozzle exit.
What is choked flow for a converging diverging nozzle?
Choked flow is a fluid dynamic condition associated with the venturi effect. When a flowing fluid at a given pressure and temperature passes through a constriction (such as the throat of a convergent-divergent nozzle or a valve in a pipe) into a lower pressure environment the fluid velocity increases.
What happens to the sound speed as the flow goes through the converging diverging nozzle with supersonic flow at the exit?
The general design of a converging-diverging nozzle is such that the initially low speed gas is accelerated as it is squeezed into the throat (with minimum diameter) at which it reaches the speed of sound. It is then accelerated further as it is now a supersonic flow moving through a diverging nozzle.
What is nozzle efficiency?
[′näz·əl i‚fish·ən·sē] (mechanical engineering) The efficiency with which a nozzle converts potential energy into kinetic energy, commonly expressed as the ratio of the actual change in kinetic energy to the ideal change at the given pressure ratio.
What is a converging nozzle?
Converging nozzles, as shown in Figure 1, are tubes with an area that decreases from the nozzle entry to the exit (or throat) of the nozzle. As the nozzle area decreases, the flow velocity increases, with the maximum flow velocity occurring at the nozzle throat.
How does Laval nozzle work?
The gas flow through a de Laval nozzle is isentropic (gas entropy is nearly constant). As the gas exits the throat the increase in area allows for it to undergo a Joule-Thompson expansion wherein the gas expands at supersonic speeds from high to low pressure pushing the velocity of the mass flow beyond sonic speed.
Why do converging nozzles become choked?
The flow accelerates out of the chamber through the converging section, reaching its maximum (subsonic) speed at the throat. Flow through the nozzle is now choked since further reductions in the back pressure can’t move the point of M=1 away from the throat.
Which among the following is an example of a converging diverging nozzle *?
De-Laval nozzle
Which among the following is an example of a converging-diverging nozzle? Explanation: De-Laval nozzle is an example of a converging diverging nozzle. It a tube that is pinched in the mid marking with a particular balance.
How is nozzle efficiency calculated?
The nozzle efficiency, ηn, is defined as the ratio of the actual enthalpy drop to the isentropic enthalpy drop.
How does a Laval nozzle work?
What are the applications of a converging diverging nozzle?
One of the most common application of a converging-diverging nozzle is in a supersonic wind tunnel. The inlet flow into the converging section is subsonic and as the cross sectional area of the converging section decreases, the flow velocity increases until it reaches sonic condition at the throat.
How does the Mach number of a nozzle increase?
In a steady internal flow (like a nozzle) the Mach number can only reach 1 at a minimum in the cross-sectional area. 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.
How to calculate the cross-sectional area of air flow through a nozzle?
Ahmed M Nagib Elmekawy, PhD, P.E. Problem Specification Consider air flowing at high-speed through a convergent-divergent nozzle having a circular cross-sectional area, A, that varies with axial distance from the throat, x, according to the formula A = 0.1 + x2; -0.5 < x < 0.5 where Ais in square meters and xis in meters.
When is the flow through the nozzle subsonic?
Figure 3a shows the flow through the nozzle when it is completely subsonic (i.e. the nozzle isn’t choked). The flow accelerates out of the chamber through the converging section, reaching its maximum (subsonic) speed at the throat.