Phase-Doppler Interferometry Spray Flux Measurement

Solution Overview

Problem

Accurately determining spray flux using phase-Doppler interferometry is challenging due to the inability to accurately characterize the effective sampling area of the measurement volume, especially when droplet trajectories are not aligned parallel to the primary velocity component, leading to measurement errors and inaccuracies in flux calculations.

Innovation Solution

A system and method that corrects for measurement errors by determining the effective sampling area based on particle trajectory and primary marks, such as droplet diameter, and performs validation to adjust the sampling area, ensuring accurate calculation of spray flux by accounting for trajectory-dependent and saturation-related biases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If phase-Doppler interferometry is used to measure spray flux, then non-intrusive measurement capability is achieved, but measurement accuracy deteriorates when droplet trajectories are not aligned parallel to the primary velocity component

Engineering Contradiction:

Core Design Contradiction:

Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent transforms the measurement approach by changing the parameter used for flux calculation from assuming parallel trajectories to using the actual measured trajectory angle. By incorporating the trajectory angle θ as a variable parameter in the flux calculation formula, the system accurately computes flux regardless of droplet alignment, resolving the contradiction between non-intrusive measurement and accuracy.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If the effective sampling area is calculated assuming parallel droplet trajectories, then calculation simplicity is maintained, but measurement accuracy deteriorates due to trajectory-dependent sampling area variations

Engineering Contradiction:

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent modifies the effective sampling area calculation by introducing the trajectory angle θ as an additional parameter. The sampling area A(θ) is calculated as A₀·cos(θ), where A₀ is the nominal sampling area. This parameter change allows accurate representation of trajectory-dependent sampling effects while maintaining relatively simple computational implementation.

Inventive Principle:

Principle #35Parameter changes

3Difficulty of detecting and measuring

If mechanical patternation (sampling rakes and grids) is used to measure spray flux, then measurement capability is achieved, but intrusiveness increases and small droplet measurement accuracy deteriorates

Engineering Contradiction:

Core Design Contradiction:

Difficulty of detecting and measuringVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical sampling rake/grid system with an optical measurement system (phase-Doppler interferometry). This substitution eliminates physical intrusion into the spray flow while maintaining measurement capability. The optical system detects droplet parameters non-intrusively, avoiding the harmful effects of mechanical interference with the spray structure.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Measurement precision

If droplet trajectory alignment is enforced to improve flux measurement accuracy, then measurement precision improves, but device complexity and operational difficulty increase due to mechanical requirements

Engineering Contradiction:

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of forcing the spray to align with the measurement system (traditional approach), the patent inverts the approach by having the measurement system accommodate arbitrary spray orientations. The trajectory angle θ is measured and used to correct the flux calculation, allowing accurate measurements without mechanical alignment requirements.

Inventive Principle:

Principle #13The other way round (Inversion)

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

Enables accurate, real-time measurement of spray flux in various applications, including agricultural settings, by providing a live feedback mechanism for spray nozzle control, and improves the precision of flux-based particle characterization instruments by accounting for droplet trajectory and size-dependent sampling areas.

Implementation Method 1

phase-Doppler interferometry (PDI, PDA, PDPA)

Methodology Applied

Scientific EffectPhase-Doppler interferometry: Doppler Effect

Implementation Method 2

acquiring raw particle data for the particles passing through a measurement volume

Methodology Applied

Scientific EffectLight scattering: Scattering

Data Source

PatentUS11536638B2System for determining an ensemble characteristic of a particle-laden flow

Publication Date: 2022.12.27

AI summary

A system and method are described for rendering a characteristic for a set of particles passing through a measurement volume of a particle optical measurement system. The method includes acquiring raw particle data for the particles passing through the measurement volume. The raw particle data comprises a set of raw particle records. Each particle record comprises at least: a trajectory of at least one particle, and a second primary mark of the at least one particle whose value influences an effective sampling area corresponding to the measurement volume. The method includes generating and storing an effective sampling area based upon: the trajectory of the at least one particle, and the second primary mark. Thereafter, an ensemble characteristic is rendered for the set of particles by performing an operation on the sampling area-corrected set of particle records.