Numerical Simulation of Flow Characteristics for Supercritical CO2-Sprayed Polyurethane Resin
Chichao Li1, Chengrui Zhang1, Minghua Xiang2
1College of Science, Nanjing Forestry University, Nanjing 210037, China.
Polymers
|April 13, 2024
Summary
Supercritical CO2 (scCO2) spraying reduces toxic VOC emissions in polyurethane coating applications. Simulations show higher scCO2 fractions improve spray distance, while increased pressure enhances droplet uniformity for better coating processes.
Area of Science:
- Materials Science and Engineering
- Chemical Engineering
- Environmental Science
Background:
- Conventional paint spraying releases harmful volatile organic compounds (VOCs).
- Supercritical CO2 (scCO2) spraying offers a greener alternative by reducing VOC emissions.
- The fluid dynamics of scCO2 coating processes require thorough investigation.
Purpose of the Study:
- To numerically simulate scCO2 spraying of polyurethane coatings.
- To investigate the effects of inlet pressure and scCO2 volume fraction on spray characteristics.
- To provide theoretical guidance for optimizing scCO2 polyurethane spraying.
Main Methods:
- Computational fluid dynamics (CFD) simulations were employed.
- The study modeled the scCO2 spraying process of polyurethane coatings.
- Parameters investigated included inlet pressure and scCO2 volume fraction.
Main Results:
- Higher scCO2 volume fractions led to lower fluid density and increased spray velocity and distance.
- Increased coating content and inlet pressure resulted in higher discrete phase model (DPM) concentrations.
- Optimized inlet pressure ensures uniform droplet distribution within the 30° spray range.
Conclusions:
- scCO2 spraying is a viable, low-VOC alternative for polyurethane coating.
- Fluid dynamics are significantly influenced by scCO2 concentration and inlet pressure.
- Simulation results offer practical insights for enhancing scCO2 coating technology.
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