Twin-Screw Extruder Devolatilization Prediction via Flow Segmentation

Solution Overview

Problem

The Latinen's model formula fails to accurately predict devolatilization performance in twin-screw extruders due to its inability to consider the changing flow behavior of the nonvolatile mass solution containing volatile mass within the devolatilization region.

Innovation Solution

A devolatilization performance prediction method that computationally determines the flow state of the solution in the devolatilization region, incorporating the flow state on the screw channel surface, the gap between the screw and barrel, and the downstream channel surface, and uses this information to predict devolatilization performance by separating the flow path into three distinct profiles and accounting for surface update efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the Latinen's model formula is used for devolatilization performance prediction, then the prediction can be performed using a simple multiplication of boundary film area and diffusion rate, but the prediction accuracy deteriorates because the flow behavior of the nonvolatile mass solution is not considered

Engineering Contradiction:

Improveprediction method complexityVSAvoiddevolatilization performance prediction accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The devolatilization region is divided into three distinct flow path profiles: (1) solution flowing on the screw channel surface, (2) solution flowing in the gap between screw and barrel, and (3) solution flowing on the downstream screw channel surface. This segmentation allows each profile's unique flow characteristics to be analyzed separately, improving prediction accuracy while maintaining manageable computational complexity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention introduces dynamic surface update efficiency factors (K1, K2, K3) that account for the continuous changing flow behavior of the nonvolatile mass solution as it moves through the devolatilization region. These dynamic factors replace the static assumptions of traditional models, enabling accurate prediction of devolatilization performance under varying operational conditions

Inventive Principle:

Principle #15Dynamics

2Productivity

If the boundary film surface area and diffusion rate are multiplied to predict devolatilization, then the calculation is computationally simple, but the prediction fails to account for the incessantly changing flow profile and exposed surface layer in twin-screw extruders

Engineering Contradiction:

Improvecalculation efficiencyVSAvoidadaptability to dynamic flow conditions

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The invention introduces dynamic surface update efficiency factors (K1, K2, K3) that account for the continuous changing flow behavior of the nonvolatile mass solution as it moves through the devolatilization region. These dynamic factors replace the static assumptions of traditional models, enabling accurate prediction of devolatilization performance under varying operational conditions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The devolatilization region is divided into three distinct flow path profiles: (1) solution flowing on the screw channel surface, (2) solution flowing in the gap between screw and barrel, and (3) solution flowing on the downstream screw channel surface. This segmentation allows each profile's unique flow characteristics to be analyzed separately, improving prediction accuracy while maintaining manageable computational complexity

Inventive Principle:

Principle #1Segmentation

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

This method provides a highly adaptable and accurate prediction of devolatilization performance by considering the dynamic flow behavior and surface update efficiencies, improving the accuracy of concentration predictions post-devolatilization.

Implementation Method 1

Dd is the diffusion coefficient (m2/s) of the volatile mass contained in the nonvolatile mass solution

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 2

the nonvolatile mass solution containing volatile mass is incessantly flowing in the screw and hence both the profile of the solution formed in the barrel and the screw by the revolutions of the screw in the devolatilization region and the exposed surface layer are changing incessantly

Methodology Applied

Scientific EffectConvection: Convection

Data Source

PatentUS8306799B2Devolatilization performance prediction apparatus and devolatilization performance prediction method

Publication Date: 2012.11.06 THE JAPAN STEEL WORKS LTD

AI summary

A devolatilization performance prediction apparatus for a solution devolatilization process using a twin-screw extruder is described. The devolatilization performance prediction apparatus determines a flow state of the solution in the twin-screw extruder, simulates the solution devolatilization process based on the flow state, and predicts a performance of a devolatilization process conducted with the twin screw extruder based on the simulation.