Session: Medical Devices and Pharmaceuticals

Paper Number: 158173

158173 - Validation Studies of an In-Silico Model to Predict Laminar Conduit Flushing With Specific Application to Fluid-Filled Medical Devices 

Abstract: 

Validation Studies of an In-silico Model to Predict Laminar Conduit Flushing with Specific Application to Fluid-Filled Medical Devices

Siva Balasubramanian^1*, Ulas Ayaz², Wesley Underwood³, Christopher A. Basciano¹

¹BD, Digital Engineering, BD Technologies, and Innovation, 21 Davis Drive, Durham, NC 27709

²BD, 1 Becton Drive, Franklin Lakes, New Jersey 07417

 ³BD, 120 S State College Blvd #100, Brea, CA 92821

 

Medical devices often contain flow conduits that require regular flushing to ensure medication dose accuracy and prevent medication interactions for patients. Computational models that use physics-based fluid simulations can be employed to assess the effectiveness of this flushing process. This study presents the validation efforts of the in-silico model, aimed at establishing a credible in-silico approach that can be used for device design evaluations.

The objective of flushing is to replace “old fluid” in a flow conduit with “new fluid”. The effectiveness of flushing is captured with two key metrics:  i) concentration of the fluid that is expelled from the conduit that is flushed, and ii) volume of the “old fluid” that remains inside the conduit.  Benchtop physical experiments predominantly emphasize the first metric; however, benchtop measurements of the second metric present significant challenges for multiple device designs. Computational models, on the other hand, can make predictions of both metrics and provide a more comprehensive flushing assessment than benchtop experiments alone.

This study aims to evaluate the in-silico model performance across different geometric configurations with a consistent inflow rate of “new fluid”. The flow conduits will feature three distinct geometries: i) a straight tube with a circular cross-section, ii) the first geometry with an expansion region in the middle, and iii) a H-shaped conduit with two closed-off ends to create intentional stagnant flow regions. Concentrations from the expelled fluid in the flow conduits will be analyzed using a microplate reader. The volume of “old fluid” remaining inside the conduit will be evaluated using images captured during and after the flushing experiments. Both outputs are evaluated against comparable results generated by the computational model. This in-silico model is a transient, laminar, single-phase computational fluid dynamics (CFD) simulation that will utilize ANSYS Fluent 2023R1. CFD simulations incorporate two distinct species to represent the "old fluid" and the "new fluid” within the conduit.

Preliminary comparisons between the benchtop experiments and CFD simulations for the straight tube with a circular cross-section indicate the "new fluid" fully replaces the "old fluid”. Initial simulation flush volume estimates fall within the range of experimental data obtained from three replicates under similar flow conditions. Similar comparisons will be conducted for other geometric configurations, with an increased number of replicates for each configuration.

 

 

Presenting Author: Siva Balasubramanian BD

Presenting Author Biography: Siva Balasubramanian is a Staff Engineer in the Digital Engineering Group at BD. He has fifteen years of experience using Computational Fluid Dynamics (CFD) to study multiphase and porous media flows in biomedical applications, supporting product development efforts at BD. Siva holds a Bachelor of Engineering (B.E.) in Mechanical Engineering from Anna University in India and a Master of Science (M.S.) in Mechanical Engineering from North Carolina State University.

Authors:

Siva Balasubramanian BD
Ulas Ayaz BD
Wesley Underwood BD
Christopher Basciano BD