# What is Nozzle: Definition and 168 Discussions

A nozzle is a device designed to control the direction or characteristics of a fluid flow (especially to increase velocity) as it exits (or enters) an enclosed chamber or pipe.
A nozzle is often a pipe or tube of varying cross sectional area, and it can be used to direct or modify the flow of a fluid (liquid or gas). Nozzles are frequently used to control the rate of flow, speed, direction, mass, shape, and/or the pressure of the stream that emerges from them. In a nozzle, the velocity of fluid increases at the expense of its pressure energy.

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1. ### Rocket thrust equation in under-expanded nozzle

Hello, so the thrust equation goes like: F = (m dot)*v_e + A_e*(p_e - p_a), where F ... thrust [N] m dot ... mass flow rate [kg/s] v_e ... velocity of exhaust [m/s] A_e ... area of the exit nozzle plane [m2] p_e ... pressure of the exhaust at the exit of the nozzle [Pa(a)] p_a ... ambient...
2. ### How to design an overexpanded nozzle

Suppose there is a steady source of compressed air/gas at 5 barA pressure, and that will be released through an overexpanded convergent-divergent nozzle. I want to know how to design such a nozzle and what would be the parameters for that. And also what would be the minimum pressure at the exit?
3. ### Thickness of normal shock zone (e.g. in nozzle)

Under certain conditions, a supersonic flow in a nozzle will result in a "normal shock", an abrupt change in pressure and velocity. In the videos I've looked at, they draw the P and v graphs with a vertical step at that point. But in practice, I assume there will be a non-zero transition zone...
4. ### Plasma thruster - plasma instability in magnetic nozzle

Plasma instability may be a solution for magnetic nozzle plasma thrusters https://phys.org/news/2022-12-plasma-instability-solution-magnetic-nozzle.html Kazunori Takahashi (Tohoku University), Christine Charles (ANU, Canberra, AU) & Rod W. Boswell (Tohoku University) Wave-driven electron...
5. ### De Laval nozzle exit pressure

In case of De Laval nozzle, the static pressure at the exit can be as low as 1/3rd of the ambient/release pressure. Kindly look at the conditions of operation part of the page. At present, I want to know any real life example (in as much detail as possible) of a De Laval nozzle where the exit...
6. ### Sonic velocity at the throat of a convergent-divergent nozzle

Sufficiently pressurised (difference between inlet and release pressure is enough to create supersonic flow) gaseous fluid is being released through a convergent-divergent nozzle. And it's a known fact that if pressure difference is sufficient, a convergent-divergent nozzle can release gaseous...
7. ### B Beam of air: Extending the range of a fan

If one Googles for "laminar flow nozzle", one finds many interesting tutorials on creating a nozzle for a laminar water jet; a stream of water that remains coherent over a long distance without breaking up. These typically consist of a large-diameter tube with regions inside (like sponges and...

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9. ### A What determines particle size in an atomizing spray nozzle?

Hi all Another random, kinda open-ended question here. Sorry for that. I found myself reading about atomizing nozzles in oil burners, and got curious about the physics of atomized sprays. I didn't have much luck researching this on my own, so I'm turning to you all. It was the kind of situation...
10. ### Nozzle loss coefficient that increases with Reynolds number?

Hi, I started to think about the drag coefficient of a sphere. At high Reynolds number Cd drops of suddenly when the boundary layer separates. If the Reynolds number is increased further, Cd increases with increasing Re. (I'm thinking about what is referred to as "post critical separated flow")...
11. ### Solving Chemical Equilibrium Concentrations Within a Rocket Nozzle

I would like to write a program to calculate the equilibrium concentrations of 10 or more chemical species at any axial location along a quasi 1D isentropic methane-liquid oxygen rocket nozzle. Is anyone aware of any good textbooks that cover this topic in depth, specifically dealing with large...
12. ### Momentum Thrust of an Over-Expanded Rocket Nozzle

Hi All, I'm trying to get a better understanding of the momentum thrust given by an over-expanded rocket nozzle (I realize this case voids the isentropic flow assumption used for the 1D isentropic gas expansion equations typically used for rocket engine design since the normal shock is not an...
13. ### 2D vs 3D Method of Characteristics for Rocket Nozzle Design

Hi all, I'm working on programming a simple 2D method of characteristics program to design the nozzle wall contour for a supersonic rocket nozzle. I'm wondering roughly what sort of difference I should expect from a 2D vs 3D method of characteristics program and where I could find a good...
14. ### Divergent nozzle for releasing pressurised gas

I have air/gas pressurised gas (pressure is 7 barG). I want to know what are the parameters of the divergent nozzle needed so that the pressurised gas can be released to atmospheric pressure level smoothly and necessary enthalpy conversion can be achieved i.e. the air/gas will accelerate to its...
15. ### The most efficient nozzle shape

We all know that a convergent nozzle can increase the velocity of a fluid at the throat/exit than the inlet. But there are different type of nozzles available in market now like parabolic nozzles, straight nozzles and elongated nozzles. I want to know which shape/geometry is the best to get the...
16. ### Flow of a Non Viscous Fluid Through this Nozzle

My first post here! I have calculated everything i need, except the thickness of the second layer dZ*, therefore i can't solve V3/V2=(R2ˇ2)/(R3ˇ2) Trying for days now, i would appreciate any help.
17. ### Cooling nozzle - convection power

Hi, when modeling convective cooling in FEA one needs to define film coefficient ##h## and ambient temperature ##T_{amb}##. The software calculates convective heat flux using this data and current surface temperature ##T_s##: $$q=h(T_{s}-T_{amb})$$ However, modeling of moving cooling nozzle may...
18. ### Water stream projection distance calculation for different nozzle shapes

Hello, I have built a device and i want to test different types of nozzles. Problem is; the size of the nozzles i need are hard to find in company stock. So i need to make sure before i make any order. I have no background or degree any related area so it is hard to understand the equations...
19. ### Position of the fan inside a convergent nozzle

I want to present two scenarios here. First, there is a convergent nozzle shaped structure having a fan/blower fitted inside. In this case, the fan/blower is fitted at the throat of the nozzle. The inlet to throat ratio isn't important here. And the second scenario, the same nozzle is used but...
20. ### Calculating the force from a pump + nozzle system

I am attempting to calculate the force (in KgF) of a water pump + nozzle system. I have the pump curve (head vs. flow rate) for the pump, the diameter of the connection hose (2 inches) and the nozzle diameter (1 inch). The connection hose between the pump and nozzle is very short (approx 10 cm)...
21. ### Fluid passing through a convergent-divergent nozzle

Suppose, there is a convergent-divergent nozzle where the inlet and the outlet both has 5 sq cm area while the throat has 1 sq cm area. A pressurised compressible fluid at 5 barA pressure having velocity 10 m/s entered the c/d nozzle. The back pressure i.e. the pressure at the outlet is 1 barA...
22. ### I Optimal Copper Pipe Size for Misting System

I am attaching a standard 5/8" garden hose with approximately 70psi pressure to a copper pipe that is capped on the opposite end with mist nozzles mounted periodically along its length. I want the pressure at each mister to be as similar as possible. The hose attaches at the base, a solid line...
23. ### What is the pressure change in this wash nozzle?

I have one question about the many wash nozzles. The pump has 20 GPM @ 1000 PSI , the pipe size is 1" and connect 20 nozzles. So the 1/4" nozzle may be 1GPM @ 1000 PSI. But the nozzle standard show the 1GPM is about 10 PSI. and 1000psi need 10 GPM. Can anyone know how to calculate the nozzle...
24. ### Sonic velocity inside a convergent nozzle

This time, i have a question that came to my mind a few days ago. There is an ideal nozzle having inlet to throat ratio of 8:1. Air will enter the nozzle at around 84 m/s velocity. it can be easily understood that the velocity will become sonic much ahead of the throat. And I am wondering what...
25. ### How to manufacture this nozzle?

Hi guys , Need help and suggestion in finding best way to manufacturing this nozzle. Thanks
26. ### Most efficient convergent nozzle

I want to know what's the most efficient type convergent nozzle available now at present. I means what's the shape that is most efficient for a convergent nozzle. By efficiency, I want to mean that the inlet velocity to throat velocity ratio will be as close as possible to the throat area to...
27. ### B Could steam be expanded through a nozzle to get 0°C gas?

Obviously expanding the gas cools it down. I'm interested if you could boil water and then expand the high pressure steam to cool it down to 0°C. Or are there subtler thermodynamics that would prevent this?
28. ### Water reach (Hose without and with a nozzle)

Homework Statement A hose of inside diameter ##1.5cm## can reach a distance of ##1.5m##. A nozzle is inserted in the hose and water can now reach ##24m##. What is the inside diameter of the nozzle? The height is the same in both cases. Homework Equations Use continuity equation...
29. ### Paradox of a convergent nozzle fed by an electric fan

Let us assume we have a cylindrical wind tunnel having a 0.5 m diameter fed by an electric fan. The cross-sectional area of the wind tunnel would be A1 = (PI/4) D1^2 = 0.196349541 m2. Let us suppose the motor driving the fan has a power rating of 1,500 W. At this stage, let us assume that the...
30. ### Blower fitted with a convergent nozzle

Recently I have some conversation with an electrical engineer and from him I cam to know about a peculiar information. We were talking about what will happen if we put a convergent nozzle before a electricity driven fan/blower. I have concentrated what will happen at the throat and other...
31. ### What is the difference between nozzle (or a ventury) and flow control valve?

In both the cases, the flow cross section area of the pipe is reduced.But in case of nozzles the velocity increases,pressure reduces and the flow rate is maintained.But in case of flow control valve, flow rate changes.(Assuming the fluid to be incompressible) Why is there a difference between...
32. ### Pressure on the Walls of a Rocket Motor Bell Nozzle

Is the pressure due to the hot gas exhaust stream on the inside walls of a rocket motor bell nozzle positive or negative? Does the rocket exhaust exert a outward pressure on the nozzle walls due to the sheer volume of the exhaust gases or is the pressure a negative one due to the exhaust stream...
33. ### Estimation and validation of water pressure at nozzle

ρ I am trying to estimate and validate the pressure of water exiting a nozzle. For an unknown reason, the validation is consistently twice as high as the estimation. Here the approach: Estimation: I am using the dynamic pressure equation for the estimation: q = 1/2 * ρ * u2 where, q = dynamic...
34. ### Why variable geometry nozzles are not used on rocket engines

Why is it that variable geometry nozzles, like those found on jet engine(iris nozzles), are not used as rocket nozzle to provide better altitude compensation?
35. ### The diameter of the exhaust nozzle of jet engines

Hello, Can anybody please tell me the typical diameter of the exhaust nozzle of a jet engine? I know, there are different types of engines and nozzle types also vary. For instance, I am interested to know the typical diameter of the nozzle of a turbofan engine. Thanks
36. ### Venturi nozzle, Bernoulli

Hello I`m working on a vacuum project, and I am trying to understand how the vacuum ejector I am using works. I understant the basic principle of how it works, but can anybody here try to explain the concept in detail, taking into consideration that I am using air? Most of the stuff i find...
37. ### Questions about Pressure and a nozzle

Good day everyone. I have a few question that I would like to confirm. Currently I am doing a project that rinses a plastic pallet. The type of nozzle I am looking at is a 65 degree full cone nozzle. Pressure = 0.7 MPa. Flowrate = 3.88 lpm. Pallet size is 1300mm x 1300mm x 100mm. Q1. Is it...
38. ### Blower fitted with De Laval Nozzle

I want to know whether we can create supersonic flow with a blower fitted with De Laval Nozzle. We all know that convergent-divergent i.e. De Laval Nozzles can create supersonic flow. Let's make it more clear. Suppose we have blower in our hand that can create an airlfow (air will be at STP) of...
39. ### Regression rate of fuel in rocket nozzle

So we have: stability for n < 1 instability for n > 1 I assume to get the time growth, I have to integrate the above first eqn. However I also get ln(δpc) at the LHS from the integrating. However the above equation for time growth removed that ln(δpc) and thus I can't...
40. ### Divergent Nozzle Homework: Integrating to Get 5

Homework Statement where the boldface type denotes a vector quantity. In general, the incremental surface dS may be expressed as r dψ R d∅. Examining Figure 1, we see that dS = R2 sin∅ dψ d∅ for this particular nozzle. Substituting Equations 3 and 4 in Equation 2 and integrating ∅ from zero...
41. ### Bernoulli's equation, Venturi effect, hydraulic head, nozzle

Hi, I have this problem: I have a vertical tube 1 meter D, in the bottom end there is a nozzle with 0,5 m D. The tube is full of water. the tube length is 10 meters and the nozzle length is 2 meters. I need to calculate the power of this by this equation: W = Q * g * h * p where W is watt, Q...
42. ### Control Volume of single expansion ramp nozzle (SERN)

Hi guys, I need to determine the performance of a single expansion ramp nozzle (SERN) from CFD results with different nozzle pressure ratios (NPR). For some NPR the nozzle is overexpanded and for some underexpanded. Now the impact of the control volume definition on especially the axial thrust...
43. M

### Nozzle Conservation of Momentum

Homework Statement I am happy to re-write the question, but I'm just leisurely working through a list of problems I found online, so here is the link (with picture). http://web.mit.edu/2.25/www/5_pdf/5_01.pdf Homework Equations Cons of Momentum Cons of Mass The Attempt at a Solution a) I...
44. ### Power drawn by a water pump to project water through nozzle

Homework Statement [/B] This is problem 10.27 in the Exercises for the Feynman Lectures on Physics, or Problem C-2 in Chapter 10 of Leighton and Vogt's Exercises in Introductory Physics. Homework Equations Using ##v_f^2 = v_i^2 + 2 a S## for the water in the vertical direction, we can find...
45. ### Rocket Nozzle with combined equilibrium/frozen flow

Homework Statement I am using the NASA CEA code to generate Isp and thrust data for the SSME. I solve the problem twice, once with a frozen flow condition and a second time with an equilibrium flow condition. However, there is a third request for solving the problem with equilibrium flow from...
46. ### Design a converging/diverging nozzle

I am intending to design a CD nozzle that produces 20mN thrust under atmospheric conditions. The reservoir pressure will be 1.4 bar, and the ambient pressure will be 1 bar. The other variables are adjustable. This will in the end be sent out for fabrication.My process is as follow, May I know...
47. ### I Nozzle Reaction Forces

I have been reading many examples of control volume calculations regarding nozzles They all end up with a reaction force on the nozzle in the direction of the flow. I can't understand this from a Conservation of momentum perspective. I would expect that the reaction force, by Newtons third...
48. ### Mass Flow Rate of Pressure Regulator

Hey, I have an air tank that is at a set pressure, say 3000psi, and I have attached a regulator to the end that regulates the pressure down to 800psi. As the valve on the tank is opened the pressure and the mass in the container will decrease. If there was no regulator the mass flow rate would...
49. ### How to change desired flow rate of the nozzle

Hello, We have a system with a 70 bar pump and 9 nozzles connected to the pump lines. Total flow rate is 2 l/m. Is there a way to change only one nozzle flow rate manually, with a pressure regulator valf just behind that nozzle? Thank you.
50. ### Air Tank Discharging Through A Nozzle - Unsteady Flow

Hey, So I have a system where there is an air tank (0.2Litres @ 3000psi, 293K) and I have a convergent-divergent nozzle attached directly to it. What I want to know is an expression for how the mass flow rate varies with time as the mass in the tank decreases causing the pressure to decrease...