Aerosol Pressure Reduction System for Particulate Sampling

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Solution Overview

Problem

Conventional pressure reduction systems for aerosol streams from high-pressure environments, such as gas turbine engines, fail to reduce pressure without significantly altering the non-volatile particulate matter concentration, making it challenging to obtain representative samples for measurement.

Innovation Solution

A pressure reduction system with two expansion orifices and a transition tube that gradually reduces the pressure of aerosol streams from high to intermediate and then to low pressure, maintaining a constant volumetric flow rate and using isentropic expansion and isobaric heating to prevent condensation and maintain particulate concentration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If conventional pressure reduction systems are used to reduce aerosol stream pressure to ambient pressure, then the pressure is successfully reduced, but the non-volatile particulate matter concentration is greatly altered

Engineering Contradiction:

Improveaerosol stream pressureVSAvoidnon-volatile particulate matter concentration

Core Design Contradiction:

Stress or pressureVSQuantity of substance

Solution Approach 1:

The pressure reduction process is divided into two distinct stages: first expansion orifice for initial pressure reduction, and second expansion orifice for final pressure reduction to ambient pressure. This segmentation allows each stage to be optimized independently, preventing excessive concentration changes that would occur in a single-stage system.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system changes physical parameters (pressure, temperature, flow rate) in a controlled sequence through the two expansion orifices and heating section. By adjusting these parameters gradually rather than abruptly, the particulate matter concentration is maintained more faithfully throughout the pressure reduction process.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If pressure is reduced to enable accurate particulate measurement, then measurement capability is improved, but the representativeness of the sample is degraded

Engineering Contradiction:

Improveparticulate matter measurement accuracyVSAvoidparticulate concentration representativeness

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The heating section positioned between the two expansion orifices performs preliminary action by warming the aerosol stream before the second pressure reduction. This prevents condensation and particulate formation that would alter concentration, thereby preserving sample representativeness while enabling subsequent accurate measurement at ambient pressure.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The heating section acts as an intermediary element between the two expansion orifices. It mediates the transition by controlling temperature and preventing unwanted phase changes or condensation, thus maintaining the integrity of the particulate matter concentration throughout the pressure reduction process.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 measurement of non-volatile particulate matter by maintaining the representative concentration of aerosol streams at high pressure, allowing for precise characterization and emission reduction verification.

Implementation Method 1

the first expansion orifice through which an aerosol stream comprised of non-volatile particulates is delivered to the first chamber from the high pressure environment, wherein the aerosol stream has a first pressure drop after passing through the first expansion orifice from a high pressure to an intermediate pressure

Methodology Applied

Scientific EffectIsentropic expansion: Adiabatic Cooling

Implementation Method 2

the second expansion orifice through which the aerosol stream is delivered to the second chamber from the first chamber, wherein the aerosol stream has a second pressure drop after passing through the second expansion from the intermediate pressure to a low pressure

Methodology Applied

Scientific EffectIsentropic expansion: Adiabatic Cooling

Implementation Method 3

using isentropic expansion and isobaric heating to prevent condensation and maintain particulate concentration

Methodology Applied

Scientific EffectIsobaric heating: Heating

Data Source

PatentUS11346754B2Pressure reduction system and method for reducing the pressure of high pressure aerosols

Publication Date: 2022.05.31 GENERAL ELECTRIC CO

AI summary

A pressure reduction system and methods therefore that include features for reducing the pressure of a high pressure aerosol to ambient pressure without significantly changing the characteristics of the aerosol are provided. In this manner, the non-volatile particulate matter concentration in a sample stream obtained from the aerosol stream at ambient pressure is representative of the non-volatile particulate matter concentration that was present in the aerosol stream at high pressure prior to the pressure reduction.