Annular Laval Nozzle for Flexible, Lower-Pressure Atomization

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Solution Overview

Problem

Existing Laval nozzles with full-surface spray patterns are limited in application range and require high pressures for atomization, leading to inefficient and inflexible fluid atomization.

Innovation Solution

A Laval nozzle design with an annular minimum flow cross-section between a wall and a constriction element, allowing for a non-full-surface spray pattern and reduced pressure requirements, with the constriction element being movable to adjust spray characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a Laval nozzle with full-surface spray pattern is used, then atomization can be achieved, but high pressures are required and application range is limited

Engineering Contradiction:
Improveapplication rangeVSAvoidpressure requirements
Core Design Contradiction:
Adaptability or versatilityVSStress or pressure

Solution Approach 1:

The nozzle flow cross-section is segmented into multiple regions (annular minimum flow cross-section between wall and constriction element) to create a non-full-surface spray pattern. This segmentation allows the nozzle to achieve atomization at lower pressures while expanding application possibilities through flexible spray pattern control.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The constriction element is made movable relative to the wall, allowing dynamic adjustment of the minimum flow cross-section area and spray characteristics. This dynamic capability enables the nozzle to adapt to different application requirements without changing pressure conditions, resolving the contradiction between adaptability and pressure requirements.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If a Laval nozzle with full-surface spray pattern is used, then atomization can be achieved, but spray pattern flexibility is limited

Engineering Contradiction:
Improvespray pattern flexibilityVSAvoidnozzle structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

By making the constriction element movable relative to the wall, the nozzle structure enables flexible adjustment of spray patterns (full-surface, hollow cone, or directional sprays) without requiring multiple fixed nozzle designs. The dynamic adjustment mechanism provides spray pattern flexibility while maintaining relatively simple nozzle construction.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If the minimum flow cross-section is formed between wall and constriction element, then non-full-surface spray patterns are achieved, but nozzle structure becomes more complex

Engineering Contradiction:
Improvespray pattern varietyVSAvoidnozzle construction
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The nozzle interior is segmented into regions defined by the wall and movable constriction element, creating annular minimum flow cross-sections that produce non-full-surface spray patterns. This segmentation approach achieves spray pattern variety through geometric division rather than complex mechanical systems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The movable constriction element serves multiple functions: it defines the minimum flow cross-section area, controls spray pattern type (full-surface, hollow cone, directional), and adjusts spray characteristics. This multi-functionality reduces the need for multiple separate nozzle designs, offsetting the added structural complexity with operational versatility.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The nozzle achieves flexible and efficient fluid atomization with reduced pressure, enabling a variety of spray patterns and optimized flow behavior, suitable for applications like exhaust gas treatment in combustion plants.

Implementation Method 1

Laval nozzles are known in the prior art that have a flow cross-section that narrows to a minimum flow cross-section in one flow direction and then expands again. Using a Laval nozzle, it is possible to accelerate a fluid to supersonic speeds without causing severe compression shocks.

Methodology Applied
Scientific EffectLaval nozzle effect: De Laval Nozzle

Implementation Method 2

The flow cross-section of the nozzle according to the invention is annular. The nozzle according to the invention has a wall and, in addition, a constriction element spaced apart from the wall, wherein the minimum flow cross-section is formed between the wall and the constriction element. Preferably, a gap, in particular an annular one, is formed between the wall and the constriction element, which has or forms the minimum flow cross-section.

Methodology Applied
Scientific EffectAnnular flow constriction:

Implementation Method 3

The present invention relates to a nozzle for atomizing a fluid, wherein a flow cross-section of the nozzle narrows in a flow direction or main flow direction to a minimum flow cross-section and then expands again. The pressures required for atomizing a fluid using the Laval principle for the fluid to be atomized and/or compressed air mixed with the fluid are reduced compared to known Laval nozzles with a full-surface circular or elliptical cross-section.

Methodology Applied
Scientific EffectAtomization:

Data Source

PatentEP3812031B1Nozzle for atomizing a fluid and combustion system
Publication Date: 2025.08.27 RS RITTEL GMBH
  • EP3812031B1 patent drawingFigure 1
  • EP3812031B1 patent drawingFigure 2
  • EP3812031B1 patent drawingFigure 3

AI summary

Nozzle (1) for atomizing a fluid (F), wherein a flow cross-section of the nozzle (1) narrows in a main flow direction (R) to a minimum flow cross-section (QM) and then widens again, wherein the minimum flow cross-section (QM) is annular, and/or wherein the nozzle (1) has a wall (2) and additionally a constriction element (3) spaced apart from the wall (2), wherein the minimum flow cross-section (QM) is formed between the wall (2) and the constriction element (3).