Engineering Nozzle
An engineering nozzle is a shaped duct or orifice designed to accelerate a fluid by converting pressure energy into kinetic energy, thereby increasing the fluid's velocity. Nozzles are critical components in rocket engines, gas turbines, steam turbines, and fluid spray systems. In a converging nozzle, the cross-sectional area decreases in the flow direction, while a converging-diverging (de Laval) nozzle is used to achieve supersonic flow.
Key Formula
V2 = sqrt(V1² + 2×(h1 - h2))
LaTeX: V_2 = \sqrt{V_1^2 + 2(h_1 - h_2)}
| Symbol | Meaning | Unit |
|---|---|---|
| V_1 | Inlet velocity | m/s |
| V_2 | Exit velocity | m/s |
| h_1 | Inlet specific enthalpy | J/kg |
| h_2 | Exit specific enthalpy | J/kg |
Worked Example
Problem
Steam enters a nozzle with negligible inlet velocity and an enthalpy of 3200 kJ/kg. It exits with an enthalpy of 2900 kJ/kg. Calculate the exit velocity.
Solution
Step 1: Inlet velocity V1 ≈ 0 m/s, h1 = 3200 kJ/kg = 3,200,000 J/kg, h2 = 2900 kJ/kg = 2,900,000 J/kg. Step 2: V2 = √(0 + 2 × (3,200,000 − 2,900,000)) = √(2 × 300,000) = √600,000. Step 3: V2 = 774.6 m/s.
Answer
V2 ≈ 775 m/s
Types of Nozzles and Their Flow Characteristics
| Nozzle Type | Geometry | Flow Regime | Application |
|---|---|---|---|
| Converging | Decreasing area | Subsonic | Steam turbines, spray nozzles |
| Converging-diverging | Throat + diverging | Supersonic | Rocket engines, jet engines |
| Sonic (critical) | At throat | Mach 1 | Flow metering |
| Annular | Ring-shaped exit | Subsonic/supersonic | Aerospike rockets |
Interactive Tools
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Related Terms
Diffuser (engineering)
An engineering diffuser is a component that decelerates a flowing fluid, converting kinetic energy back into pressure energy, thereby increasing the static pressure. Diffusers are used in compressors, wind tunnels, aircraft intakes, and HVAC systems to recover pressure with minimal losses. The performance of a diffuser is characterised by the pressure recovery coefficient, which compares actual pressure rise to the ideal isentropic value.
Compressor (engineering)
A compressor is a mechanical device that increases the pressure of a gas by reducing its volume, thereby increasing its energy content. Compressors are fundamental components in refrigeration systems, gas turbines, pneumatic tools, and industrial processes where pressurised gas is required. The work input to a compressor is governed by thermodynamic principles, and the efficiency of the compression process determines overall system performance.
Thermodynamic Cycle (engineering)
A thermodynamic cycle is a series of thermodynamic processes that return a system to its initial state, enabling continuous conversion of heat into work or vice versa. Engineering thermodynamic cycles such as the Rankine, Brayton, and Otto cycles form the basis of power plants, jet engines, and internal combustion engines respectively. The thermal efficiency of a cycle quantifies the fraction of heat input that is converted into net work output.
From Old French "nosel" or "nozzle", a diminutive of "nose", referring to a projecting spout. The term entered engineering vocabulary in the 17th century with the development of steam jets and bellows. The de Laval nozzle was invented by Swedish engineer Gustaf de Laval in 1888.