Design of Draw Resistance of Pressure Drop Standards for Tobacco Products Based on the Flow Distribution

Abstract

Cigarette draw resistance and filter pressure drop are both critical physical indicators for the tobacco industry, which use testing equipment to measure the two parameters. Pressure drop standards are used as transfer standards to ensure the accuracy and reliability of the testing equipment. Pressure drop standards are generally cylindrical rods having a certain number of parallel capillaries. To address the issue of how to design and fabricate pressure drop standards quickly and conveniently, this paper proposes a design method for pressure drop standards based on structural parameters. The method uses a mathematical model of the internal airflow of the standard including the entrance effect into a circular capillary and uses an iterative calculation algorithm accordingly. By iterative calculation, the structural parameters of the pressure drop standard, namely, diameter and length of the capillaries, were obtained, along with the relationship between the draw resistance of the standard and the flow rate in each capillary. The accuracy of the mathematical model was validated by comparing and analyzing the experimental and theoretical draw resistance of standards with different structural parameters. The experimental results showed that the relative error between the measured draw resistance and the calculated draw resistance was below 8%, which proves the reliability and validity of the mathematical model, and provides theoretical support for the design and fabrication of pressure drop standards.

Keywords

• structural parameters
• pressure drop standard
• design
• capillaries size
• length